Odour Management Plan

Shotover Wastewater Treatment Plant

DRAFT FINAL

Odour Management Plan March 2012

Shotover Oxidation Ponds Odour Management Plan

DOCUMENT CONTROL SHEET

Project

Shotover Oxidation Ponds (Resource Consent 2008.239 Condition 2)

Report


Date

March 2012

GL/A-Code: Version

Author

Draft v1

M. Heather/ S. Pile

Draft v2

M. Heather/ S. Pile

Working Version 10/11 Working Version 15 March 2012 Rev Working Version 15 March 2012 Rev2

Document Reference: Reviewed

D14761 Signature

Date

Distribution

R. Potts, S. Smith (CPG), R. Cudmore (Golder) & M. O’Malley (QLDC) ORC and SPL, RPL

08/11/10

CPG, Golder Associates, QLDC and United Water

10/11/10

M. Heather/ S. Pile

N/A

25/01/11

Otago Regional Council, SPL and RPL QLDC and Otago Regional Council

S. Smith (CPG)

R. Potts (CPG), M O’ Malley

15/3/2012

SPL/ RPL

M. Heather (QLDC)

-

21/5/2012

Otago Regional Council


TABLE OF CONTENTS 1.

2.

3.

Purpose of the Odour Management Plan ........................................................................................ 1 1.1

Consent Details ....................................................................................................................... 1

1.2

Plan Objectives ........................................................................................................................ 2

1.3

Review Provisions ................................................................................................................... 2

Description of the System ............................................................................................................... 3 2.1

General .................................................................................................................................... 3

2.2

Process Details ........................................................................................................................ 4

Key Personnel................................................................................................................................. 5 3.1

3.1.1

QLDC Staff ...................................................................................................................... 5

3.1.2

Otago Regional Council ................................................................................................... 5

3.2

4.

Specific Responsibilities .......................................................................................................... 6

3.2.1

QLDC Management ......................................................................................................... 6

3.2.2

3-Waters Operations and Maintenance Contractor (VW)................................................. 6

Odour Sources ................................................................................................................................ 7 4.1

Wet Well & Milliscreen ............................................................................................................. 7

4.1.1

Process Details ................................................................................................................ 7

4.1.2

Odour Sources................................................................................................................. 7

4.2

Treatment Ponds ..................................................................................................................... 8

4.2.1

Process Details ................................................................................................................ 8

4.2.2

Odour Sources................................................................................................................. 8

4.3

5.

Contact Details ........................................................................................................................ 5

Septage Reception Pond ......................................................................................................... 9

4.3.1

Process Details ................................................................................................................ 9

4.3.2

Odour Discharge............................................................................................................ 10

Odour Prevention & Minimisation Measures ................................................................................. 11 5.1

Personnel .............................................................................................................................. 11

5.2

Milliscreens ........................................................................................................................... 11

5.2.1

House Keeping Measures ............................................................................................. 11

5.2.2

Screen Cleaning & Maintenance ................................................................................... 11

5.2.3

Milliscreen Failure and Response .................................................................................. 12

5.3

Wet Well & Milliscreen Room................................................................................................. 12

5.3.1

Odour Extraction System Specification .......................................................................... 12

Shotover Oxidation Ponds Odour Management Plan 5.3.3

Milliscreen Biofilter ......................................................................................................... 13

5.3.4

Biofilter Checks .............................................................................................................. 14

5.4

5.4.1

Operating procedures .................................................................................................... 15

5.4.2

Causes of Dissolve Oxygen Depletion ........................................................................... 15

5.4.3

Pond Turning Anaerobic ................................................................................................ 17

5.4.4

High Rainfall Events ...................................................................................................... 17

5.5

7.

8.

Septage Reception Pond ....................................................................................................... 19

5.5.1

Sub-surface Discharge of Tanker Loads........................................................................ 19

5.5.2

Aeration ......................................................................................................................... 19

5.5.3

Operating Procedures .................................................................................................... 20

5.5.4

Unpermitted Deposit of Waste in Septage Reception Pond........................................... 20

5.5.5

Discharge to River Delta ................................................................................................ 20

5.6 6.

Oxidation Ponds .................................................................................................................... 15

Site Power Outages ............................................................................................................... 21

Ambient Odour Monitoring ............................................................................................................ 22 6.1

Boundary Assessments ......................................................................................................... 22

6.2

Compliance Assessments ..................................................................................................... 22

Odour Complaints, Logging and Response Procedures ............................................................... 22 7.1

Complaint Logging ................................................................................................................. 22

7.2

Information provided by Complainant .................................................................................... 23

7.3

Assessments/Investigations by QLDC ................................................................................... 23

7.3.1

Plant Odour Surveys (boundary investigations) ............................................................. 23

7.3.2

Optional Compliance Assessment ................................................................................. 24

7.4

QLDC Actions ........................................................................................................................ 24

7.5

Recording and Incident Reporting ......................................................................................... 24

7.6

Odour Reporting and Follow-up ............................................................................................. 25

System Review and Reporting Procedures................................................................................... 26

Glossary of Terms ................................................................................................................................. 27 References ............................................................................................................................................ 28 Appendix A Resource Consents ............................................................................................................ 29 Appendix B Operations and Maintenance Procedures .......................................................................... 40 Appendix C Process and Instrument Diagram ....................................................................................... 44 Appendix D Odour Complaint Form ....................................................................................................... 45 Appendix E Odour Survey Form ............................................................................................................ 46 Appendix G Technical Details and MSDS for the Conhur Odour Spray ................................................ 47 Appendix G Remarkables Park Ltd/ Shotover Park Ltd Review ............................................................ 48


List of Tables and Figures Figure 2-1 : Legal Boundaries of the WWTP ........................................................................................... 3 Figure 2-2 : Aerial photograph of the Shotover Oxidation Ponds ............................................................. 4 Table 1-1: Discharge Permits .................................................................................................................. 1 Table 3-1: Relevant QLDC Staff Contact List .......................................................................................... 5 Table 3-2: Relevant ORC Contact Details ............................................................................................... 5 Table 5-1: Cause and Prevention of Pond DO Depletion ...................................................................... 16


1. Purpose of the Odour Management Plan 1.1

Consent Details

Queenstown Lakes District Council (QLDC) was granted two discharge permits by the Otago Regional Council (ORC) for the continued operation of the Shotover Oxidation Ponds in May 2010. The discharge permits are as follows: (a) Discharge permit 2008.239 permits the discharge of contaminants to air, and (b) Discharge permit 2008.240 permits the discharge of treated wastewater to water. A summary of relevant details of both permits is shown in Table 1-1. Table 1-1: Discharge Permits Consent No.

Description

Issue Date

Expiry Date

Conditions

2008.239

To discharge odour to air associated with the ongoing operation of the Queenstown wastewater treatment and disposal system

13 May 2010

18 March 2044

Refer to Appendix A

2008.240

To discharge treated wastewater to the Shotover River for the purpose of operating the Queenstown wastewater treatment and disposal system

13 May 2010

22 April 2014

Refer to Appendix A

Copies of both permits are included in Appendix A. Condition 2 of Discharge Permit 2008.239.required QLDC to prepare an Odour Management Plan (OMP). Condition 2 states the following: “The consent holder shall adopt the best practicable option (BPO) to prevent or minimise odour discharges from the site. The best practicable options shall be set out in an odour management plan that is to be peer reviewed by a suitably qualified odour expert approved by the consent authority prior to being submitted to the consent authority within 4 months of the commencement of this consent. The plan and associated peer review shall be submitted to Remarkables Park Limited (RPL) and Shotover Park Limited (SPL) for review and comment in accordance with condition 8. The consent holder shall ensure that the consent authority has the most recent copy of the plan at all times. The plan shall provide for the best practicable option(s) to prevent or minimise odour discharge from the site to be in place within 12 months of the commencement of this consent. The plan shall be to the satisfaction of the consent authority and shall include, but not limited to: (a) a description of the potential sources of discharge of odour to air on site; (b) the methods adopted to minimise odour including, but not limited to, the operation and ventilation of the wastewater treatment system, and the storage and management of screenings and sludge; (c) the method for complying with condition 15 within 12 months of the commencement of this Status –

Draft Final

1

-1-

March 2012 Ref  Drft Final Shotover Ponds OMP Working Doc 15 March 2012 Rev2.docx

Shotover Oxidation Ponds Odour Management Plan consent; (d) management and operational procedures and contingency plans to prevent or minimise odour and ensure ongoing compliance with condition 14; (e) a method for recording and responding to complaints from the public in accordance with condition 13; (f) a description of the monitoring required to comply with condition 10 of this consent; (g) assignment of responsibility for implementation and updating the plan; (h) a survey plan showing the legal boundary of the Queenstown wastewater treatment and disposal site.” Roger Cudmore from Golder Associates was confirmed by the ORC as a suitably qualified odour expert to peer review the OMP.

1.2

Plan Objectives

The objectives of this OMP are: 

To ensure that the requirements of Condition 14 of discharge to air permit 2008.239 are met and adhered to. Condition 14 states that: “There shall be no discharge of odour, as a result of the exercise of this consent, that is noxious, dangerous, offensive or objectionable to the extent that it causes an adverse effect beyond the designation boundary of the site, in the opinion of an authorised officer of the consent authority”.



To set out the physical and procedural measures that must be implemented to mitigate odour to acceptable levels.



To enable the Shotover WWTP to be operated and maintained in a manner which employs best practicable options to prevent the discharge of objectionable or offensive odours.

1.3

Review Provisions

QLDC will review the OMP once each year in October, as per Condition 3 of Resource Consent 2008.239. There will be continued consultation with Remarkables Park Limited (RPL) and Shotover Park Limited (SPL) regarding the annual OMP review. Refer to Appendix F for the initial RPL/ SPL review of the Shotover Odour Management Plan.

Status –

Draft Final

2

-2-



2. Description of the System 2.1

General

The Shotover Oxidation Ponds Wastewater Treatment Plant (WWTP) provides wastewater servicing for wastewater generated within Queenstown (including Frankton), Arrowtown and Arthurs Point. The WWTP is located at Frankton Ladies Mile Highway, Queenstown. Access to the WWTP is off Tucker Beach Road on the northern side of Frankton Ladies Mile Highway. A survey plan showing the legal boundary of the wastewater treatment and disposal site (in accordance with Condition 2 (h)) is in Figure 2-1 and an aerial photo showing the site is shown in Figure 2-2. The Shotover Ponds are due to be upgraded to an advanced mechanical treatment plant and land disposal system within four years. The new treatment plant will be developed on the same site as is currently being used. Figure 2-1 : Legal Boundaries of the WWTP

Status –

Draft Final

3


Shotover Oxidation Ponds Odour Management Plan Figure 2-2 : Aerial photograph of the Shotover Oxidation Ponds

2.2

Process Details

Veolia Water (VW) currently manages and operates the WWTP under Contract QLDC 11-113. The WWTP consists of an inlet milliscreen, a septage reception pond, two partially aerated ponds (Pond 1 and Pond 2), and a maturation pond (Pond 3). The method of treatment employed at the WWTP, after the screening of solids via the Milliscreens, is via partially aerated, facultative ponds. Both Ponds have additional mechanical aeration capacity present. Pond 1 and Pond 2 are operated in parallel with the wastewater flow from the Milliscreens split between the ponds. Pond 3 acts as a tertiary "maturation" pond accepting secondary treated wastewater from both Pond 1 and Pond 2.

Status –

Draft Final

4



3. Key Personnel 3.1

Contact Details

3.1.1 QLDC Staff The contact details of key personnel responsible for implementing this plan and their responsibilities are listed in Table 3-1: Table 3-1: Relevant QLDC Staff Contact List Organisation QLDC – 3-Waters Manager QLDC – Resource Consent Manager VW – Contract Manager VW – O&M Engineer SJ Allen Queenstown Engineering Pumptech

Name Gerry Essenberg Melanie Heather

Email [email protected]

Phone (03) 441 0475

Cell 027 224 6597

Fax (03) 450 2223

[email protected]

(03) 450 1719

N/A

(03) 450 2223

Jason Climo

[email protected]

(03) 450 9241

027 555 9011

(03) 443 1395

Currently vacant position

(03) 450 9245

027 338 8998

(03) 443 1395

[email protected] [email protected]

(03) 688 5669 (03) 442 3036

027 437 7087

(03) 684 4880 (03) 442 3023

Simon Spark Steve Columbus

027 250 7874

3.1.2 Otago Regional Council Contact details for the ORC are shown in Table 3-2. Table 3-2: Relevant ORC Contact Details Organisation Otago Regional Council

Status –

Name Address Haines Battrick, 70 Stafford Street, Consents Officer Dunedin 9016

Draft Final

5

Phone (03) 474 0827 After hours phone (pollution incidents): 0800 800 033



3.2

Specific Responsibilities

3.2.1 QLDC Management The QLDC is the sole asset owner of the WWTP and has overall responsibility for ensuring staff are available, appropriately trained and funded. The QLDC’s Resource Consent Manager is responsible for the following:   

Ensuring that Resource Consent conditions are adhered to; Ensuring that the Odour Management Plan is reviewed annually and that RPL, SPL and the ORC are consulted and provided with copies of any updates to the OMP, as required; and Notification to the ORC of any consent condition breaches of Resource Consent 2008.239.

3.2.2 3-Waters Operations and Maintenance Contractor (VW) The 3-Waters Operations and Maintenance Contractor (currently VW) is responsible for the following:  

Status –

Day to day responsibility for the management of the plant, and Response to complaints.

Draft Final

6



4. Odour Sources The following section describes the main sources odour emission from the WWTP site.

4.1

Wet Well & Milliscreen

Towards the end of last financial year a project to upgrade the existing screens and odour control at this structure revealed that the concrete was extensively corroded and the recommendation from the Structural Engineer engaged to review the life expectancy was that the cost to remediate the existing structure would likely equal the cost of a new structure. This view was supported by a representative from a supplier of material that is used in lining such old structures. Based on this and the fact that a new inlet works would need to be constructed as part of a new plant, it was recommended to go ahead with the construction of the inlet works now and funding for this is included in the current Annual Plan. The building has been removed from the screens area and the skips are being monitored to ensure they are removed in a timely manner. There are a number of complex pipe realignments involved in the design on the incoming sewer lines that need detailed planning and this is currently on-going. The new structure is currently being designed and will be going to tender by the end of March. It is hoped to have the facility complete before the end of August 2012 in order to mitigate the odours from this area. This OMP will be revised again once the design of the inlet works is finalised.

4.1.1 Process Details Incoming sewage to the plant can be anoxic or anaerobic on arrival. When exposed to air and turbulence, sulphides and other odorous compounds can be released. Odour generation cannot be directly controlled by any measures taken at the WWTP. Odour emissions are entirely due to the nature of the incoming sewage, so measures to contain and treat these odour emissions are necessary. Factors influencing odour generation include:  

Total residence time and temperature of wastewater in the sewerage reticulation system; and Turbulence at the inlet structure, which creates conditions suitable for odours to escape.

4.1.2 Odour Sources Odour generation occurs from two locations in this area: 

Status –

The Milliscreens Wet Well: This is where the inlet sewage is delivered to the two milliscreens. The wet well has significant turbulence (with associated odour release) so it needs to be covered and the air from its headspace extracted and treated. Draft Final

7


Shotover Oxidation Ponds Odour Management Plan 

The Milliscreens: Due to the exposure of sewage to the air during the screening process or during cleaning/maintenance, odorous compounds can be released from the sewage flow.

The two Milliscreens sit over a grease trap. Both screens are Triobex rotating drums, horizontal mesh type with 1 mm slots. One screen is currently operational, with the second screen on site ready for installation at the new structure.. Recent refurbishment has included the removal of the existing building due to its deteriorating condition. The screens are automatically controlled and only operate when flow is sensed through either of the flow meters on the Arrowtown line or Frankton/Queenstown line. Screenings of greater than 1 mm size roll down the screen drum and discharge into a transportable skip. The skip containing the screenings is collected by a contractor once a week. The screenings are disposed of at the QLDC municipal landfill. This is being monitored closely and if necessary, the screenings will be removed more often. A brief inspection of the working screen is undertaken at the same time as the screenings are collected. The contractor cleans and hoses down any debris caught in the screen and that may have been deposited on the Milliscreen Room floor. The screen is turned off during maintenance, which reduces odour generation potential. A cover is placed over the full skip that is then removed from the premises and taken to landfill.

4.2

Treatment Ponds

4.2.1 Process Details Screened wastewater discharges into two facultative oxidation ponds (8.3 ha total area), operated in parallel. Mechanical aeration is provided for via nine aspirating aerators in Pond 1 and 2 and four brush-cage type aerators in Pond 1 and three in Pond 2. Pond 1 has a surface area of 5.5 ha and a depth of 1.35 m. The nominal volume of Pond 1 is 73,200 m3 and sludge build-up is currently estimated to be approximately 460 mm. Therefore, with the sludge volume, the effective volume of Pond 1 for wastewater treatment is about 47,960 m3. Pond 2 has a surface area of 3.9 ha, and depth of 1.35 m. The sludge depth is estimated to be 470 mm. The total volume of Pond 2 is 53,420 m3. Therefore, less the sludge volume, the effective volume of Pond 2 is about 34,720 m3. Wastewater from Ponds 1 and 2 pass into Pond 3, a maturation pond. Pond 3 has a surface area of 6.5 ha, and depth of 1.5 m. This equates to a volume of 90,070 m3. The discharge from the maturation pond is via a constructed channel to the Shotover River.

4.2.2 Odour Sources Odour emissions can be generated from the ponds via the following: Status –

Draft Final

8



Mechanical Aeration The physical process of aeration can generate aerosols, which have odours associated with them. “Turn-over” Event A “turn-over” event occurs when excessive sludge build up within the ponds coincides with warmer air temperatures (which occur during late spring/summer), which encourages increased microbial activity. Anaerobic gas production within the sludge layer encourages it to float to the surface, which results in odorous sludge being directly exposed to air. The most recent “turn-over” event recorded for the WWTP pond system was in 2003. With the current desludging of the ponds this risk will be eliminated in the short to medium term. Biological Process Upsets Biological process upsets within the ponds can be brought on by:    

Overloading of the ponds’ organic capacity. Overloads lead to excessive oxygen demand, which result in anoxic pond conditions; Algal population die-off due to a parasitic fungal attack; Following an algal bloom event; and A slowdown in algal activity, due to lack of sunlight and oxygen in the pond.

It is worth noting that turn-over of the ponds does not necessarily mean they are at capacity, but is rather an indication that they may need to be de-sludged. From experience elsewhere, it is found that the most likely turn-over time is in late spring/summer, when temperatures increase. This results in the increase in microbial activity and gas generation within the sludge layer. Pond Desludging A recent sludge survey reports indicate an estimated 2,535 dry tonnes (tDS) of accumulated sludge needs to be removed from the three Shotover WWTP ponds. To reduce the risk of pond turn-over and to optimise the treatment capability of the ponds, it is proposed to desludge the two facultative ponds and maturation pond in 2012. Desludging, depending on the method and management, has the potential to cause short-term odours.

4.3

Septage Reception Pond

4.3.1 Process Details A 2,000 m3 capacity concrete lined basin serves as a reception facility for septic tank, grease trap and high strength industrial wastewater disposal (such as winery wastewater). This facility is separate to the Status –

Draft Final

9


Shotover Oxidation Ponds Odour Management Plan other treatment processes on the WWTP site. Treated effluent from the septage reception pond is discharged into Pond 1. The wastewater disposed of into the basin has the following characteristics:   

A higher proportion of fats and grease; Generally more anoxic in nature; and A high solids concentration.

Therefore, the septage reception pond can be a particularly significant odour source, if not treated appropriately.

4.3.2 Odour Discharge Discharging wastewater and septage from vacuum tankers into the septage reception pond has previously involved contractors dumping collected septage from above the surface of stored wastewater in the basin. As the tanks were emptied, aerosols (and associated odours) were generated. In response to concerns raised during the consenting phase of Project Shotover, VW installed a system that allows the tankers to dispose of their load via a pipe that has an outlet underneath the surface of the disposal basin. The tankers now fix a hose to a Cam-Lock fitting and are able to empty their load without generating unnecessary odours. The new vacuum tanker discharge method has been successful at reducing aerosol and odour generation from this process.

Status –

Draft Final

10



5. Odour Prevention & Minimisation Measures The operating & preventative measures to be implemented at the WWTP to minimise odour generation are detailed in this section. Several assets and odour mitigation equipment are used on the WWTP site, these are listed in Section 4 of the Shotover Ponds O&M Manual (VW, 2010).

5.1

Personnel

Ensure appropriately trained staff:   

5.2

Are available 24 hours per day, 7 days per week to respond to plant malfunctions and odour complaints; Are competent and knowledgeable about all aspects of the operation and maintenance of the treatment plant and processes; and Continually review the performance of the wastewater treatment plant and understand how to respond to changes in the sampling results, effluent quality and/or levels of odour generated from the site.

Milliscreens

This section will be updated when the design of the new inlet works is complete.

5.2.1 House Keeping Measures To minimise fugitive odour sources from around the site:   

Keep the plant and surrounding area clean and free from rubbish. Collected screenings and grease shall be stored in an appropriate, covered container and removed to the QLDC municipal landfill once a week. Checking of the Milliscreens for any damage.

5.2.2 Screen Cleaning & Maintenance        Status –

Ensure the screen is cleaned periodically with high pressure water to remove accumulated solids and debris. Refer to Section 7 of the Shotover Ponds O&M Manual (VW, 2010) for details on cleaning the interior and exterior of each screen. A high pressure pump is housed in a shed next to the Milliscreen Room, to supply washwater for cleaning the Milliscreen drums. Isolate the interior and exterior sparge isolation valves, to prevent any high pressure water spray occurring whilst cleaning the screens. Use a step ladder to access the drum interior by the two front doors. Using a soft edge spade or paddle scrape or cut through rag build up and scoop to the discharge hopper. Use a stiff bristled plastic yard broom to broom the screen clean. Do not use hard metal implements that could become stuck or damage the screen webs. Draft Final

11


Shotover Oxidation Ponds Odour Management Plan     

After exiting the drum, close all doors and reopen all switches and valves in reverse order. Operate screen for several revolutions and manually activate a sparge cleaning cycle. Carry out Programmed Maintenance (PM) as per the Shotover Ponds O&M Manual (VW, 2010), and summarised in Appendix B, with monthly inspections and maintenance on the rotary mill screen, valves and screen chain. The current monthly Preventative Maintenance checks are undertaken once per month by Queenstown Engineering – Tel: 03 442 3036. All screenings (accumulated material) are to be removed into a container (trailer) for removal by the contractor to the QLDC municipal landfill.

5.2.3 Milliscreen Failure and Response Should a fault occur that prevents the operation of the Milliscreens, then the following measure will be implemented: 

5.3

Identify the cause of the fault (electrical, mechanical, system). This can be done by running through the regular maintenance checks for the Milliscreens, so that each component is assessed for its working order.

Wet Well & Milliscreen Room

5.3.1 Odour Extraction System Specification Odour emissions from the wet well and operating screen are to be drawn by a draft fan that discharges odorous air to a soil bark bed biofilter system. This requires the wet well to be covered and the screens to be operated with their covers closed so that the air space within both systems operates under a slight negative pressure (vacuum). The minimum vacuum recommended for the head space of air within the wet well and within the covered screens is - 10 Pascal gauge pressure (Pa) and an ideal operating target of 20 Pa (gauge). The level of enclosure of the wet well and sealing of the base of the screen will dictate the ventilation flow rate necessary to achieve these nominal vacuums within the screen and wet well head space and therefore ensuring containment of odorous air that is directed to the biofilter system.

5.3.2 Breakdown of Extractor Fan to Biofilter The contractor will use a local electrical contractor specialising in industrial power and control work to service and maintain electrical and mechanical items at the WWTP. Daily visits from Operators include checks on all treatment processes and odour control mechanisms. Any technical breakdown of equipment will be either repaired in situ as soon as practicably possible, or (as in some cases) sent away for repair. The extractor fan fitted inside the Milliscreen Room is powered by a 0.75 kW motor which could be replaced at short notice if necessary. VW have an on-call roster ensuring that a first call and back up Operator are available 24 hours a day, 365 days a year. The mechanical and electrical contractor employed by VW also have their own on-call roster ensuring specialised technical support is available Status –

Draft Final

12


Shotover Oxidation Ponds Odour Management Plan at any time, should major breakdowns or malfunctions occur with any critical plant and/or machinery within the treatment plant. Daily Fan Checks  Check controls for the blower fan are in the “off” condition.  Check the belt drive is running normally without undue slack or over tension by hand turning.  Check controls in the main switch board room for the blower fan are in the “on” condition.  Check resilient duct fixings are tight and have no sign of leakage.  Check the fan housing for hotspots and excessive vibration.

5.3.3 Milliscreen Biofilter A biofilter is used to treat odorous air ventilated by the Milliscreen and wet well air extraction fan. The biofilter consists of a narrow 0.5 metre deep trench within which perforated corrugated drainage-coil pipe has been laid which runs out of the western side of the Milliscreens. The trench runs for approximately 5 m, is 1 m wide and is filled with bark mulch and soil. The fan discharges the extracted air stream into the base of the biofilter bed and is forced to transfer up through the soil bark media. This media absorbs odorous compounds and contains naturally occurring microbes that metabolise these to non-odourous by-products including ammonia, carbon dioxide and water. The media substrate used in the biofilter bed is currently a bark-mulch mixture. The bed is contained below ground surface and requires frequent irrigation so to be maintained in a moist condition to facilitate the bacterial processes that assist in the removal of the odour. Biofilter operation requires the maintenance of biological processes that are relatively robust, however effective on going operation requires routine maintenance of the bed media and appropriate hydraulic loading rates that ensure odour breakthrough does not occur. Design Criteria The important design criteria for the biofilters includes hydraulic loading of the bed (m3/hr per m3 media) and bed pressure drop (mm-H2O). The recommended maximum loading rate for a soil bark or graded bark bed treating ambient air extracted from the Milliscreens are 45 and 20 m 3 air/hr per m3 media respectively. Therefore the use of a bark mulch media requires the lower media loading rate of 20 m 3 air/hr per m3 media for efficient odour removal. The maximum recommended media pressure drop is 50 mm water-gauge for soil bark biofilters and 20 mm for bark bed biofilters, and the maximum fan discharge pressure is 150 mm water-gauge. The latter includes the air distribution manifolds and laterals and can therefore be measured downstream of the Milliscreens’ fans. Biofilter Operating Criteria Key operating parameters for biofilter beds normally include inlet air temperature, bed moisture content, and bed pH. However, because ambient air is only extracted from the Milliscreen tanks, then the inlet temperature does not require control. Instead the high sulfide content of the extracted air is likely to require management of the bed pH to avoid the bed pH dropping below the design targets specified below. The media moisture content should be maintained at 30/wt% to 60/wt% dry weight basis throughout the media depth for bark bed systems and 40 wt% - 60 wt% for soil bed media designs. Status –

Draft Final

13



Mean pH is recommended to be a minimum of 6 within the upper two-thirds layer of the bed. A lower pH limit of 5 applies to the lower third layer of the bed. Biofilter Monitoring The following monitoring is to be undertaken to ensure effective odour performance from the Milliscreens biofilter.   

   

Annual monitoring of media size distribution and composition is required to monitor the gradual degradation of media in each bed. This enables their respective replacement programmes to be planned well ahead of bed failure. Pressure gauges to be installed to measure fan discharge pressure and pressure drop across the media. Annual testing of the media size distribution using a standard sieve tray analysis of media down to 2-mm size via a mass-size distribution of total mixture. Bark is deemed to be any particle above 2-mm size, whereas material < 2-mm is deemed to be the compost fraction. Samples are oven dried then sieved using a Fritsch Analysette 3 at 2 mm amplitude. Annual sieve results combined with carbon and nitrogen data indicate the extent and rate of media mineralisation. Media moisture content and pH within the upper two-thirds layer of the bed be monitored and recorded at least once per month. Monthly inspection and recording of biofilter condition, i.e. weeds, compaction, channelling etc. Documentation for recording regular inspections, measurements, design operating levels of temperature, bed back-pressure, pH and moisture content. Annual flow and pressure testing to confirm Milliscreen tank ventilation rates and biofilter loading rate.

5.3.4 Biofilter Checks      

Status –

Check outside at the end of the Biofilter bed that the duct end cap is either buried or on tight. Check the moisture content of the Biofilter bed medium (i.e. soil, shell and bark material) is moist and not dry. If moisture content is low (less than 40 wt%) use irrigation or hand held hose to moisten the medium until satisfactory measurement is achieved. Check the Manometer reading has positive pressure in the downstream duct to the biofilter and this does not exceed 150 mm water gauge. On a weekly basis ensure the irrigation system for the biofilter is timed to operate. During dry periods the bed should be kept moist. The moisture content should be similar to a watered vegetable garden. Till bed by hand or rotary hoe. Check the pH level, add lime or alkaline substrate if pH is < 6 within the top layers of the bed.

Draft Final

14



5.4

Oxidation Ponds

5.4.1 Operating procedures The aeration of the ponds is undertaken with mechanical surface or sub-surface aeration equipment. Minimum aeration capacity is indicated by electrical power inputs for aeration within the order of 3 Watts/m3. Maintaining the ongoing and continuous aeration within this range is necessary to assist the natural algal population to maintain adequate DO within the water column in the order of 2 mg/litre as normal day time operating level. This level reduces close to zero at night time when the algae expire CO2 and consume oxygen. Therefore monitoring of DO levels within the pond discharge should be at similar times of the late morning or early afternoon. To ensure routine reliable operation the following measures are required:         

Ensure the aerators are operating correctly on a daily basis and remedy if there is a fault. On a weekly basis check the aerators for excessive cavitations, vibration and damage, and remedy as per the Shotover Ponds O&M Manual (VW, 2010) and Appendix B. Carry out monthly planned maintenance on the aerators. During the winter months, inspect the caged rotor aerators for ice build-up that may sink, jam or off balance them. Undertake weekly monitoring of DO that discharges to the maturation pond and daily during peak summer months of November to February. Inspect ponds on a weekly basis for any floating scum and debris and remove any that is found. Scum accumulation can interrupt sunlight penetration which the algae need to produce oxygen. Also check for pest damage or erosion to banks. Analyse effluent from final Maturation pond as per the Resource Consent conditions. Monitor pond levels closely during high rainfall events. The stop logs controlling the flow of water between ponds and at the outlet to Pond 3 often have to be altered in order to drop the levels of the ponds when high rainfall events can increase the potential for ponds overflowing. Check effluent quality results are within ranges specified within WWTP operating configuration, and if not, the operations and maintenance contractor will investigate why not and instigate remedial actions to return the plant performance to normal operating ranges.

5.4.2 Causes of Dissolve Oxygen Depletion When working under aerobic conditions within the water-column of each pond, the oxidation ponds would have a relatively low odour potential. The scenarios that lead to depleted oxygen levels for a number of days or more are those that lead to significant odours being released and therefore management of the ponds to avoid and mitigate these scenarios is the key to successful odour management of the WWTP site. There are a number of typical and not so typical causes of the dissolved oxygen levels being depleted in the ponds. These are listed in Table 5-1 alongside the measures to avoid or mitigate these scenarios.

Status –

Draft Final

15


Shotover Oxidation Ponds Odour Management Plan Table 5-1: Cause and Prevention of Pond DO Depletion Cause of oxygen levels in Pond to deplete Pond “Turn-over”

Mitigation Measures/Responses

High benthic loading of BOD (Biological Oxygen Demand)

Inadequate aeration capacity for peak BOD loads to the system Inadequate aeration capacity during normal BOD loads to the system Algal population changes/instability

Operation problems/aerator failure preventing aeration of pond

All up-set scenarios

Status –

Draft Final

16

Maintain sludge levels below 1/3rd pond depth is a key contingency measure to avoid pond “turn over” scenarios. Break up floating sludge layer with intense agitation e.g. jet boat, running an out board motor on fixed structure within the pond. Leave broken up sludge layer to settle and re-establish normal aeration gradually as sludge layer is re-established. Detect during summer months by more frequent DO monitoring of discharge. Increase aeration if max daily DO levels fall below 2 mg/litre. This can be avoided by monitoring BOD loadings and DO levels within the water column and ensuring sufficient aeration is provided to the ponds to maintain positive oxygen content within the water column. Note: Monitoring DO within Pond 1 or 2 or the discharge from Pond 3 is undertaken at set times of the day to avoid variation in DO results due to the diurnal variations in algal activity. Often a summer time issue with increased tourist population and higher temperature that also increase benthic BOD inputs. Same actions as per above. Detected during normal routine monitoring of pond outlet and assessing trends in daily Maximum DO. Pond nominal aeration capacity needs to be increased in response. It is hard to avoid these, and can algal blooms and population changes cause sudden losses of natural aeration and high BOD burden due to dead algal mass. Similar required as for Pond “turn over” scenarios – that is intense agitation to break up the mats as they begin to occur. The use of mechanical aerators with spare capacity can break up algae mats as they begin to form. Other agitation methods, such as boats, can be used as necessary.  Identify root cause of fault (i.e. electrical, mechanical)  Electrical fault: Check condition of the main catenary wire carrying the aerator power cable to the appropriate post mounted junction box.  Electrical: Check condition of socket junction box and that PDL plug is firmly fitted into socket.  Mechanical: Disconnect the aerator motor by pulling the plug from the socket and proceed to tow the aerator to the shore for maintenance. Note that the fault relay disables the aerator on a motor overload of earth leakage fault.  Technical problems relating to aerator operation should be referred to Pumptech –Tel: 027 250 7874.  For all of the above upset conditions, monitoring of operational parameters such as BOD loading, discharge quality and DO levels is important to avoid such events occurring. Furthermore, ensuring adequate management of the sludge layer depth can be important to avoid this building up excessively.



5.4.3 Pond Turning Anaerobic Anaerobic conditions occurring within any of the ponds will result in significant odour emissions if not rectified within one to two days. When monitoring during normal daytimes of sampling return zero DO readings (that is anoxic) then the pond maybe only hours to one day away from becoming anaerobic if not already. Undertake actions as for operation problems/aerator failure in Table 5-1 as well as the following steps:          

Check all aerators are functioning. Remedy any faults. Re-test the DO level in all ponds and record. Measure inflow temperatures at each pond and record. Record daily high and low temperature from Met office or site station and record. Check the surface grease condition, if heavy add a surface degreasing agent. If one pond is still aerobic (good positive DO levels), then transfer waste as a seed liquor to the anaerobic pond. A temporary pump is a preferred method as liquor can be discharged to the warmest location. Reconfigure pontoon aerator directions to allow early sunlit water to move to cooler shaded water. If insufficient aeration continues use of a jet boat or circulating pump discharging aerially can be considered. Noise and odour discharge may cause nuisance; advise Regional Authority. Worst case scenario may dictate increasing the out flow discharge and dropping the depth level of the pond to allow sunlight penetration and aeration depth to come closer to anaerobic sludge. Alternatively check the algal state to ensure the right type of algal growth is occurring. It should not be Blue Green alga which will show a high DO level. If Sulphur levels are too high addition of Sodium Nitrate to Pond 1 & Pond 2 will encourage good algae growth and better oxidation.

5.4.4 High Rainfall Events High inflow volumes into oxidation ponds (due to high rainfall events) increases the wastewater levels as result of infiltration into the sewer network. This is a significant problem and can increase the levels of wastewater entering the treatment plant by over 5000 m3 volume. In such cases the following actions are to be taken:     

Status –

Check that the set up and status of stop logs and sluice valves for all overflow points and outlets are correctly configured. Under high flow levels, the Milliscreen may become overloaded and it may therefore be necessary to bypass this part of the treatment process. To bypass Milliscreen, lift the weir gate at V5 and ensure V6 is open to ensure flow enters Milliscreen bypass line and direct into the ponds via the splitter chamber. Refer to Appendix C. Check V3 on Arrowtown sewer line and ensure it is closed. Monitor pond levels and if high levels persist, stop logs on the following outlets may be removed;  OC1 (outlet from Pond 1 to Pond 3),  OC2 (outlet from Pond 1 to Pond 2),  OC3 (outlet from Pond 1 to Pond 2),  OC4 (outlet from Pond 2 to Pond 3),  OF3 (overflow from Pond 1 to Pond 3) Draft Final

17


Shotover Oxidation Ponds Odour Management Plan 

OC5 (discharge outlet).

5.4.5 Pond Desludging Conhur (a specialised sludge removal contractor) proposes to utilize a purpose built auger fed sludge dredge to uplift and transport the sludge for further processing. The dredge will be controlled by an onboard operator. The dredge is fitted with four individual winch ropes that help the dredge move within the pond. A welded HDPE dredging pipeline will be set up with floats attached to support it in the water. Conhur will work with the WWTP operator to coordinate any movement of the aerators or associated equipment. The dredge will traverse the pond along the predetermined gridlines and systematically uplift the sludge from the pond. The dredging runs are about three (3) metres apart, providing about one (1) metre overlap. As the process proceeds, the areas dredged are checked for residual sludge and a dredging plan is maintained. The auger head of the dredge is fitted with a plate foot on each side of the auger which prevents the auger from contacting the pond base. The auger is located nominally 50 mm above the base of the pond. The dredged sludge will be preconditioned prior to dewatering in the centrifuges. Preconditioning will be carried out in purpose built conditioning containers located adjacent to the centrifuges. The sludge is pumped from the conditioning containers and dosed with polymer prior to entry into the centrifuges. Polymer trials carried out on the sludge indicate that efficient dewatering can be achieved with the addition of approximately 5 kg/tDS of polymer. Two Z53 Flottweg high speed centrifuges will dewater the sludge. Both machines are rated to process sludge at 1.3 tDS / machine / hour. The machines are housed in containers, are trailer mounted and are set up complete with sludge pumps, macerators, polymer pumps, polymer mixing tanks and discharge conveyors. Conhur will set up the centrifuges in the flat area between Ponds 2 & 3. One centrifuge will be powered by QLDC’s 150 kVA genset to be located next to the centrifuge container. The other machine will run off a 300 kVA transformer to be installed by QLDC. The centrate from the centrifuges will be discharged via polyethylene pipes back to the oxidation ponds via gravity. Conhur will use six or eight-wheel tipping trucks to transport the sludge from the dewatering area to the temporary storage site. The internal haul route will be entirely off public roads. The trucks will have sealed tailgates with multiple locking devices to ensure no spillage of sludge. It is not proposed to cover the trucks. The treated sludge will be placed in a constructed temporary storage area to the south of the Shotover WWTP site. The storage area land is owned by QLDC and is within the Wastewater Treatment designation. A disposal area of 2 ha will be required to contain the 13,000 m3 of dewatered sludge to ensure a maximum deposited sludge height of 0.65 m is not exceeded. Hand sowing of the stored sludge with a deep rooted plant (such as lucerne) will be carried out at sufficient time intervals to allow establishment prior to winter. All stored material will be sown to allow establishment prior to the end of the growing season. On completion of the works, all surfaces will be restored to the same condition as at the time of an initial walkover survey with QLDC. Status –

Draft Final

18


Shotover Oxidation Ponds Odour Management Plan The contractor who will undertake the dewatering of the three ponds at the Shotover WWTP (Conhur) has extensive experience in the dredging and on-site dewatering of oxidation pond sludges. Their previous experience suggests that odour caused by the equipment and process they intend to operate is negligible, compared to the existing ambient site odour conditions. Conhur have prepared an Operational Management Plan (OMP) for the proposed desludging works. Their OMP contains measures to minimise and reduce odour emissions from the proposed works. If odour is found to be produced as a result of desludging operations, then the OMP indicates that the following actions will be taken: 

The contractor (Conhur) has a trailer mounted odour suppression sprayer available which will be on site in the sludge storage area for deployment if required;



All sludge transfer is by means of welded pipelines or enclosed screw conveyors; Conhur’s experience with this equipment has shown that this system greatly reduces odour to no more than the ambient conditions of the operating existing WWTP. They state (in their Operational Management Plan for the proposed desludging works) that they have never previously received any odour complaints from dewatering operations; and



Before ceasing of the contract works, Conhur will ensure that all dredged material is processed and committed to land, and remediated with lucerne or a similar deep rooted plant to minimize the occurrence of odour.

Conhur have indicated that, should the above measures become ineffective, then additional odour mitigation measures can also be deployed if required (e.g. odour suppression sprays (refer to Appendix G), capping the sludge stockpile, etc). It is suggested that SPL/RPL attend site when the desludging process has been underway for a number of weeks to help determine if there are any odours that cause them concern. This will be arranged directly between QLDC staff and SPL/RPL.

5.5

Septage Reception Pond

5.5.1 Sub-surface Discharge of Tanker Loads Septage vacuum trucks discharge wastewater loads via a connection and pipeline that discharges below the surface of the septage reception pond. This minimises the potential for odour releases from incoming loads due contact with atmosphere and the creation of turbulence. This new discharge system is designed to minimise spray and the creation of aerosols and odours. It is also a significantly safer practice for those contractors operating sucker trucks and should reduce their contact with wastewater and the potential harm this may cause.

5.5.2 Aeration The septage reception pond is aerated by two aerators to promote aerobic conditions within the septage, or else to ensure anoxic conditions do not become anaerobic and odorous. This mechanical aeration is further enhanced by the pumping of approximately 2 l/s of wastewater from Pond 1 into the basin which injects mechanically aerated wastewater from the pond system. Status –

Draft Final

19



Lime is dosed into this basin as a specific odour management control mechanism. An additional product called an 'Odour Control LLMO Activator' may also be added to the mix to further assist in neutralisation of the sulphide compounds commonly associated with odours from this facility. Both the lime and this nutrient activator are manually added by Operators as and when necessary.

5.5.3 Operating Procedures The following operating procedures and checks are specified for the septage reception pond:     

  

Dose pond with lime if Programmed Maintenance (PM) checks determine odours emanating from pond need to be neutralised. Ensure adequate supply of lime is available and is stored on site in a suitable manner. Note: Lime is ordered in bulk from Upper Clutha Transport. Ensure grill on outlet from septage reception pond is unblocked and free from debris. All contractors disposing of septage into the septage reception pond have been made aware of the new process of tank emptying. Lime and an Odour Control Activator are added to the septage reception pond in order to control the odours generated from this part of the treatment plant. Both chemicals are stored in secure compounds within the treatment plant site and are readily available for use when deemed necessary. Lime is predominately used in instances whereby operators wish to control odours from the septage reception pond. This may be in response to the planned dumping of septage by waste management contractors. Operators manually add chemicals when wearing full PPE and adhering with chemical handling guidelines. Material Safety Data Sheets are included within Appendix F of the Operations & Maintenance Manual.

5.5.4 Unpermitted Deposit of Waste in Septage Reception Pond Occasionally vacuum tankers have discharged toxic wastes that are not permitted. These discharges can severely inhibit the biological processes that partially treat the septage. A new permit system has been instigated to reduce the risk of dumping of unsatisfactory or unknown wastes. However should these occasions occur, then the Operator should:  

Dose the septage reception pond with both lime and the odour control Activator used to neutralise the odours emanating from the disposal pond. Pump wastewater from Pond 1 into the septage reception pond to restore the aerobic biological processes necessary to breakdown the wastes in this facility.

5.5.5 Discharge to River Delta 

Status –

Check if path or location has changed due to river forces weekly. If the effluent flow is not discharging into an active braid of the Shotover River, then VW will arrange to excavate an alternative channel to a new braid, or to divert a braid to the channel outfall.

Draft Final

20



5.6

Site Power Outages

A number of external factors can affect the operation of the WWTP. These factors have the potential to disrupt the odour control mechanisms currently in place. The loss of power for more than a few hours in Queenstown is a rare event and recent electricity infrastructure projects implemented by Transpower have served to provide a more reliable and robust supply to the Wakatipu basin. Loss of power will affect the primary mechanical treatment processes at the treatment plant which are the Milliscreens and aerators in the ponds. The extractor fan used to draw air into the biofilter would also cease to work. There is no standby generator at the WWTP. Risk Assessments undertaken at the site deem that it is an acceptable risk for these primary treatment processes to stop working until a standby generator can be installed.

Status –

Draft Final

21



6. Ambient Odour Monitoring 6.1

Boundary Assessments

Boundary assessments (i.e. Plant Odour Surveys, Appendix D) are used to confirm the presence of odour from the site and the likely source. They require less intensive and formal procedure compared to compliance assessments that are usually undertaken at the location of complainants residential dwellings or place of work that are aimed to establish whether the odour is objectionable and/or offensive. These types of survey are appropriate as Plant Odour Survey’s that aim to confirm the likely source of an odour complaint and the measures that may be necessary to eliminate this source. These types of assessment are the primary self monitoring tool that is used by the QDLC site operators.

6.2

Compliance Assessments

Compliance assessments, are more formal and under taken in accordance with the Ministry for the Environment’s Good Practice for Assessing & Managing Odour in New Zealand (June, 2003). These assessments are too time consuming for diagnostic type assessments at the site in response to odour complaints. They are most relevant when the aim is to assess the extent to which an odour incident represents a breach of the objectionable/offensive threshold, rather than to assist with day to day management and mitigation of odour emissions from the site.

6.3

Other Assessments

During the desludging process, the contractor (Conhur) has indicated that weekly site safety and environmental inspections will be undertaken by the site supervisor and recorded on the Safety Inspection Checklist sheet in accordance with Conhur Health and Safety Management Plan procedures.

7. Odour Complaints, Logging and Response Procedures 7.1

Complaint Logging

Resource Consent 2008.239 Condition 13 requires QLDC to keep a record of any complaints received regarding discharges of odour from the WWTP. Complaints may reach QLDC from complainants via a number of channels:     Status –

Otago Regional Council compliance staff. Direct complaints made to QLDC customer service which is logged in the Request for Service system. Directly to WWTP operators (VW). QLDC Staff who are known to complainants.

Draft Final

22


Shotover Oxidation Ponds Odour Management Plan All complainants should be encouraged to use the QLDC customer service number, 03 4410499, as this activates the appropriate response within QLDC and directs a response from the appropriate contractor.

7.2

Information provided by Complainant

Where possible/practical, the following information should be obtained from the complaint and recorded in the complaint form (Appendix D). Information to record includes:   

 

7.3

the date, time and place at which the complaint was generated; address of complainant if they are prepared to provide details; the description of the odour incident provided by the complaint including;  frequency of odour incidents (e.g. continuous, fluctuating, infrequent etc)  duration (mins, hours, days etc)  strength (very weak, weak, distinct, strong, very strong or extremely strong)  character (e.g. sewage, sewer, sulphury, pond smell, musty, acrid etc); and weather conditions at the time of the complaint (e.g. fine, wet, windy, still and cold, snowing); wind direction (N, NE, E, SE, S, SW, W, NW).

Assessments/Investigations by QLDC

7.3.1 Plant Odour Surveys (boundary investigations) Once a complaint is received, VW are to be notified and requested to carry out a Plant Odour Survey as soon as practical (Appendix E) at the following frequency, in accordance with Condition 10 of Resource Consent 2008.239:   

at least once per day for 30 days following the completion of any upgrade works that may result in discharge of odour; at least once per day for 3 days following any external complaints received and confirmed as coming from the site; and at least once per day for 3 days following any off-site odour identification as coming from the site during the odour walkover survey.

The Plant Odour Survey should be conducted by driving to different sections of the site’s boundaries and walking along these in an attempt to detect odour coming from the plant. Having assessed the wind direction, boundary locations downwind of the septage reception pond, Milliscreens and ponds would be the first to assess. The surveys are to be recorded in accordance with Resource Consent 2008.239 Condition 12 and kept for a minimum of six years:    Status –

the date, start and finish times of the survey; the wind direction and strength, and weather conditions throughout the survey period; the location and strength/intensity, character and duration of any odours observed;

Draft Final

23


Shotover Oxidation Ponds Odour Management Plan  

investigations into the source of any odour identified, whether from the site or elsewhere; and plant operating conditions at the time of the survey.

7.3.2 Optional Compliance Assessment Having obtained information from the complainant, then QLDC staff or contractors may on occasion undertake a full FIDOL (Frequency, Intensity, Duration, Offensiveness, Location) assessment of odour from the complainants’ location or nearby to assess the ambient odour and record the following:  

    

the date, time and place of assessment; the description of the ambient odour including;  frequency of odour incidents (minutes/hr, hours/day, days/month etc);  duration (mins, hours, days etc);  strength (very weak, weak, distinct, strong, very strong or extremely strong);  character (sewage, pond smell, musty, acrid etc); weather conditions during the assessment (fine, wet, windy, still and cold, etc); wind direction (N, NE, E, SE, S, SW, W, NW); Undertake a 360o assessment of the WWTP site to confirm is any other sources of ambient odour can be identified. This requires and upwind and downwind assessment of the WWTP site; Provide an opinion whether the odour was considered to be objectionable and/or offensive; and Plant operating conditions at the time of the assessment.

Note: this type of formal 360o assessment of the odour beyond the boundary is not required by the Resource Consent 2008.239, but this more formal assessment can be used at the discretion of the QDLC to confirm whether or not odour discharges from the QLDC WWTP is likely to be causing objectionable and/or offensive effects.

7.4

QLDC Actions

QDLC through VW will take any remedial actions necessary to mitigate odour emissions that complaints and/or site investigations indicate to be causing discernable and nuisance WWTP type odours to be experienced off-site. If necessary, VW will update any relevant procedures that have been modified to further minimise the chance of reoccurring odour problems.

7.5

Recording and Incident Reporting

QLDC/ VW staff are to fill out a complaint form (Appendix D) which will add to the Record of Complaints Register as well as the Plant Odour Survey (Appendix E).   Status –

Information collected from complaint (Section 7.2); Information collected by QLDC and contractors (Section 7.3);

Draft Final

24


Shotover Oxidation Ponds Odour Management Plan   

Operating conditions at the time of the complaint, including any malfunctioning or breakdown of control equipment; Corrective action taken by the consent holder to minimise the risk and extent of the recurrence of the causes of the complaint; and Any feedback from the complainant following corrective actions.

The complaint may have been received via the ORC and all this information above may not be provided to QLDC, but QLDC will try and gather as much information from the ORC as possible and update the Record of Complaints Register.

7.6

Odour Reporting and Follow-up

File complaint on Records of Complaints Register. If QLDC or VW receive a complaint directly, QLDC shall forward to the ORC a record of that complaint and corrective action within two weeks of receiving the complaint in accordance with Condition 13 of Resource Consent 2008.239. Once an odour complaint has been investigated and action agreed between QLDC and VW, QLDC will contact the complainant and advise them of the action to be taken and when that action has been completed.

Status –

Draft Final

25



8. System Review and Reporting Procedures This OMP is a “living document”, and is to be reviewed on an annual basis as per Resource Consent 2008.239 condition 3, or as required. The objectives of the OMP is to enable the WWTP to be operated and maintained in a manner which employs best practicable options to prevent or minimise the discharge of objectionable or offensive odours. QLDC will also consult RPL and SPL during the annual review process. The annual review, which will be undertaken by QLDC, will take into account the following: (a) The implications of any actual anticipated increases in flow, organic load and sludge generation (such as due to new industry or increases in population) on the performance of the treatment plant over the next 12 months, having particular regard to preventing generation of any offensive or objectionable odours; (b) The recommendations of any odour performance reviews undertaken; and (c) The recommendations of any decommissioning and construction odour management plan. The updated OMP (when amended annually, or as required) will be submitted to the ORC and RPL/ SPL.

Status –

Draft Final

26



Glossary of Terms Effluent

Discharge from the WWTP (in this case, treated effluent).

g/m3

grams per cubic meter, equivalent to milligrams per litre (mg/L). In water this is also equivalent to parts per million (ppm).

Influent

Raw wastewater stream coming into the WWTP.

Resource Consent

refers to Section 87 of the RMA. Resource consents include land use consents, coastal permits, water permits and discharge permits.

RMA

Resource Management Act 1991 and subsequent amendments.

Sludge

is a generic term for solids separated from suspension in a liquid. Commonly sludge refers to the residual, semi-solid material left from industrial wastewater, or sewage treatment processes.

WWTP

Wastewater Treatment Plant (WWTP) is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants. Its objective is to produce a waste stream (or treated effluent) and a solid waste or sludge suitable for discharge or reuse back into the environment.

Status –

Draft Final

27



References Conhur, 2012: Contract No. CT 12-008 Shotover Ponds Desludging 2012 OPERATIONAL MANAGEMENT PLAN, February 2012. MFE, 2003: Good Practice Guide for Assessing and Managing Odour in New Zealand, Ministry for the Environment, 2003. VW, 2010: Shotover Ponds Operations and Maintenance Manual, August 2010.

Status –

Draft Final

28



Appendix A Resource Consents












Appendix B Operations and Maintenance Procedures (refer to Shotover Ponds Operations and Maintenance Manual, August 2010) Location

Daily

General Operation

Record Keeping – refer Record Keeping Activities Table Resource Consent Sampling Check effluent quality results are within ranges specified within WWTP Operating Configuration. Inspection of oxidation ponds (Pond 1, Pond 2 and Pond 3) and pond wave bands. Ensure correct operation of screens and aerators. Remedy any aerators in fault. Note that neither screens nor aerators are connected to SCADA and must be manually checked to verify correct operation.

Screens and Aerators

Screenings

Remove screenings and grease to landfill. Note: All Milliscreen maintenance is undertaken by QLDC contractors – S.J Allen.

Biofilter

Irrigation system for biofilter is timed to operate.

Weekly

Enzyme dosing of aeration tank (bioaugmentation)

Weekly dosing of aeration pond with 3 varying forms of enzymes which act as sludge digesters and emulsifiers. Operators follow instruction sheet in enzyme dosing cabinet.

Electrical

Log the indicated total on each running hour meter. Investigate the cause of any unusually high or low readings. Generally survey all electrical equipment for any signs of malfunction or deterioration, noting particularly any chattering relays, too-frequent starting motors, or unusual sounds, odours, blown fuses, burnt out indicating lamps. Investigate any trouble signs promptly and remedy as necessary. Log the amperage readings from the switchboard and note the increase (if any) in current drawn in comparison with that when new. In the case of pumps and aerators, investigate impeller conditions when increase approaches 10% from new. Check each automatically controlled item of equipment through one control cycle to verify correct operation. Check line voltage to neutral. Check light fittings for burnt out tubes and bulbs and replace as necessary. Simulate each alarm condition and ensure that the respective alarm signals are properly displayed at the switchboard and by telemetry to the base station.

Electric motors

Record the hours run on task sheets

Monthly

Quarterly

Annual

Shotover Oxidation Ponds Odour Management Plan Location Milliscreen

Daily

Weekly

Monthly

Check the milliscreen for any damage.

Undertaken Monthly PM checks as follows; [note: this is currently undertaken by Queenstown Engineering].

Rotary Mill Screen 1: Check for bearing noise, vibration and security of motor and gearbox.

Grease nipples on board provided with SKF LGMT 2. Check all bolts and fittings for tightness. Fill chain oiler with Mobil Viscolite and adjust drip if necessary. Grease the chain on the milliscreen as part of the weekly PM schedule. Grease is supplied by Queenstown engineering.

Isolate drive motor and wash down pump power supply. Check internal and external of screen for fatigue cracks & breaks in structure. Check security of covers, doors, panels and guards. Check oil level in greabox. Replace @ 5000 hours or every 6 months of continuous operation. Top up to full, mark on the dip stick if necessary, with Mobil gear oil 630. Lift screen clear of support wheels. Turn wheels to check bearing condition. Check grease lines are operating and are secure. Check security of wiring to controls, electric motor and conduit in wet area around screen drive. Screen chain: Record sprocket / chain wear & check alignment. If chain sprockets are not in line or shafts are not parallel, excessive wear and early failure result. Wear on inside of chain, side walls and sides of sprocket teeth are signs of misalignment. To check alignment remove chain and place a straight edge against sides of sprocket teeth. The correct amount of slack is essential to the proper operation of chain drives. Chain should never be excessively tight around the sprockets nor so slack that whipping occurs. A properly installed chain has slight sag (approx 25mm for 1m span) on the return run. Milliscreen valves: Check valves on inlet and outlet lines into screens for leaks at gland packing and flanges. Check the operating cylinder fitted to V13 (pneumatic operated knife gate valve). Lubricate the sliding gate with a thin coat of grease to maintain function.

Quarterly

Annual To clean chains, soak and wash them in kerosene. To re-oil, soak the chains in approved chain oil then hand to drain off excess. To regrease chains in contact with water, heat an approved chain grease until it becomes a thick fluid. Soak the chains then hang them up to drain off excess (use Mobil Viscolite). Chains and their associated sprockets should always be replaced together. The chain should be replaced when it has stretched more than 2% of its original length.

Shotover Oxidation Ponds Odour Management Plan Location

Daily

Weekly

Odour control

Check the fan housing for hotspots and excessive vibration, if these are present stop the fan and correct the causes. Check the pipe connections and seals for air leaks. Check all bolts and fittings for tightness. Grease bearings through the holes provided in the housing.

Ponds

Inspect ponds for any floating scum and debris and remove any that is found. Scum accumulation can interrupt sunlight penetration which the algae need to produce oxygen. Check any pest damage or erosion to banks and repair. Check stop logs and sluice valve at discharge point from Pond 3 (OC5). Check aerators for excessive cavitation and vibration. If these are present stop the aerator and correct the cause. Remove all debris from around aerators. Inspect floats and mooring lines. Check all bolts and fittings.

Aerators

Paddle Aerators

Check rotor bearing seals for tears and damage. Check bearing grease is still clean and show no rust on bearing.

Inlet and surge chambers Discharge to river delta Electric motors

Wash down pump

Monthly

Quarterly

Annual During dry periods the bed should be kept moist. The moisture content should be similar to a watered vegetable garden. Till bed by hand or rotary hoe. Check the pH level, add lime or alkaline substrate if pH is < 6 or replace bark/soil material at 3 to 5 year intervals.

Lubricate motor with recommended grease.

Check oil level and top up gear oil. Use Mobil gear 630 mineral oil. Check for water ingress into oil. If there is stop until and arrange for removal of drive unit and seal replacement undertaken.

Direct or remote grease bearings. Snow and ice. Ensure this does not sink, jam or off balance the aerators. Check for any build up of grit, sludge or rag. Clean out if excessive. Rag build up can cause blockages. Remove the cause of rag build up. Leave the site clean and tidy. Check if path or location has changed due to river forces; order Resource consent effluent tests within 3 days if it has. Wipe the outside of the electric motors, clean to ensure adequate cooling is maintained. Check for vibration, excessive heat from bearings or windings and unusual noises. If any of these are present, stop the motor and correct the cause. While the motor is dismantled check the insulation for deterioration. If in doubt about the condition of the wiring check with an electrician. Check motor for excessive noise, heat and vibration. Check pump gland for leaks. Check valves and flanges for leaks. Check security of cabling and wiring to pump motor. Check water tank for leaks and security of pipes, fittings and covers. Check ball valve operation.

Check motor amp draw Lubricate Aerator Inspect coupling and tighten bolts Inspect propeller Inspect seals and bearings. Change lubricant oil every 12 months or 10,000 hours If operating seasonally change every 2 years.

Shotover Oxidation Ponds Odour Management Plan Location Air compressor

Mixer

Ball valves

Discharge outlet

Flow meters

Daily

Weekly

Monthly

Quarterly

Annual

Check oil level in air compressor and replace bi monthly. Drain water from the air tank. Check v belt tension and conditions. Check motor for excessive noise, heat and vibration. Check air lines to cylinder on valve. When tank is drained, hose down, inspect for damage and wear. Check all bolts and fittings for tightness. Inspect oil levels as per supplier's manuals. Check the valve for leakage at the gland, the seat and the connections. If necessary tighten or replace the gland packing, regrind the metal disks and seats or replace the composition disks, tighten connections. Loosen the gland and lubricate the packing. Tighten the gland and operate the valve. Check for leakage. Operate in-active valve through range to prevent sticking. Inspect the discharge outlet to the Shotover River Delta. If the waste flow is not entering a sufficient volume of flowing water to dilute, then arrange with plant overseer to excavate an alternative channel to a new braid. NB: resource consent may be required to work in the river. Inspect inside of the manhole and pipework for leaks. Check all bolts and fittings for tightness. Contact the supplier for adjustment or alterations. Use supplier (Streat Group, Christchurch) manual for reference.

Calibration of magnetic flow meters by contractor.


Appendix C Process and Instrument Diagram


Appendix D Odour Complaint Form


Appendix E Odour Survey Form


Appendix G Technical Details and MSDS for the Conhur Odour Spray


Appendix G Remarkables Park Ltd/ Shotover Park Ltd Review

PRODUCT SHEET “AIR REPAIR” 7D-A

OVERVIEW “AIR REPAIR” 7D-A was developed to neutralise the alkaline odorous compounds of Ammonia, Butylamine, Trimethylamine, other Amines, Skatole, VOC’s and all other compounds of a similar nature. These types of odours are associated with chemical and industrial processing and their wastes (solid and liquid), putrecible waste (household garbage), sewage treatment plants and the extended reticulation system, all animal breeding and processing facilities, and most types of industrial waste. By spraying on a timed programmed basis all odours can be eliminated. The alkaline odorous compounds react with “Air Repair” 7D-A and are neutralised of their toxic and offensive potential. A typical reaction can be shown in the following equation: NH3 (AMMONIA) + “AIR REPAIR” 7D-A = CH3COONH4 (AMINE SALT) or RCH2COONH4. This is a non-volatile Amine, therefore has no odour and is readily absorbed. “Air Repair”© products are different than nearly all other odour neutralisers or masking agents. The difference lies in the product makeup: nearly every product in the market is a blend of essential oils or plant extracts combined with a standard surfactant while “Air Repair”© products are made of food and cosmetic grade compounds and contain only 1% essential oils or plant extracts (by total volume of concentrate). Basic chemistry proves all essential oil and plant extract based products cannot truly neutralise odours; they can only mask them or encapsulate them for a period befolre releasing them again.. Essential oils and plant extracts cannot bind to, and react with, a compound such as NH3 and change the structure of that volitile compound into a non-volitile compound.

METHODS OF APPLICATION “AIR REPAIR” 7D-A can be applied by using one of the following methods to control odour.

1)Fogging System 2)Vapour Phase System 3)Direct Dosing into liquid. It is worth explaining, that, unlike masking agents, "AIR REPAIR" does not blow away in the wind. Being positively charged, it will seek out target molecules and bond to them resulting in a chemical reaction forming a non-volitile organic salt. If an “AIR REPAIR” molecule does not find a target, it will attach itself to a negatively charged surface and wait for an odorous molecule. As with all gases, the odorous molecules are constantly moving and, given time, will come into contact with an “AIR REPAIR” molecule and be destroyed.

P.O. Box 39-608, Howick, Auckland, New Zealand Telephone: +649 27 11 054 Facsimile:+649 27 11 053 www.odourcontrol.co.nz

Fogging System Fogging systems spraying “Air Repair” 7D-A are used when odour is from open-air sources. “Air Repair” products are sprayed on an interval basis depending on odour type and strength. An example of this is running the system for 30 seconds ON and 2 minutes OFF. Some examples of facilities where fogging systems can be used: -Landfills -Refuse transfer stations -Waste water / sewage treatment plants -Composting facilities -Pig farms -Sludge lagoons Fogging systems spraying “Air Repair” 7D-A are also used in indoor facilities. Some examples are: -Sewage pumping stations -Slurry pits -Refuse transfer stations Vapour Phase Systems Vapour phase systems delivering “Air Repair” 7D-A are used when odour is from ducted, or confined, air sources. This type of application is designed to inject the vapour into a continuous flow air stream that is part of an exhaust or extraction process. These types of systems are delivering vapour into the air stream continuously. Some examples of these types of problems are: -Manufacturing process exhaust airflow -Sewage plant air extraction -Sewage pumping stations -ANY air emissions vented to the atmosphere Direct Dosing “Air Repair” is exceptionally effective in capturing its target in a liquid solution. Liquid solutions only produce odours when they reach a point where cavitation occurs, say at the end of the pipe or weir. Odour is produced as a result of the reduction in water pressure and the odorous gases are stripped out of solution. This method of application is ideal for waste treatment plants, animal and fish processing plants, and pig and chicken farms, which have wash down systems where waste water is collected and stored in a settlement pond system or holding tanks. “Air Repair” molecules will attach to the odorous compounds to remove toxins from the water and, over about seven days, will spread through the whole anaerobic/facultative/aerobic pond system to remove odours. This action chemically bonds (valency bond) to the odorous compound to form a non-toxic, nonodorous organic salt. Bacteria will then break down this salt. As a result, there is no increase in BOD, and no regeneration of foul odours. “Air Repair” can best be thought of as a detoxifying catalyst that beneficially affects the pond ecology. It is extremely powerful. Any “Air Repair” product, which is not required to destroy toxic odorous compounds, will continue in the stream and neutralise any air that is stripped from the stream due to water turbulence at the treatment station or ponds.


TEST RESULTS Using 20m1 of an odorous substance to 1 ml of “Air Repair” 7D-A mixed and shaken for 10 & 30 minutes, the results are as follows: ODOROUS GAS

PPM

AFTER 10 MINUTES AFTER 30 MINUTES

HDROGEN SULPHIDE

1200

22 (70)

10 (60)

METHYL MERCAPTAN

600

9 (60)

2 (25)

AMMONIA

600

5 (30)

ZERO (20)

TRIMETHYLAMINE

250

15 (15)

10 (10)

Competitors figures in (brackets). DILUTION RATES We recommend diluting “Air Repair” 7D-A with clean water at a ratio of 1:100 (1%).


MATERIAL SAFETY DATA SHEET DATE OF ISSUE: March 2005 Not classified as hazardous. ”Air Repair” 7D-A 1. CHEMICAL PRODUCT AND COMPANY IDENTIFICATION Odour Control Systems International Limited Unit B 6 Kerwyn Ave East Tamaki Auckland New Zealand Tel: +649 27 11 054 Fax: +649 27 11 053 Product Name: “Air Repair” 7D-A Manufacturer's Product Code(s): 7D-A Use: For the control of odours in industry, wastewater, animal breeding and processing facilities and refuse handling, through chemical neutralisation. Safe for use in confined airspaces such as refuse transfer stations and material recovery facilities. UN Number: None allocated Proper Shipping Name: “Air Repair” 7D-A Dangerous Goods Class: Not classified as a Dangerous Good according to the UN, DOT (US), IACO (IATA) or IMO (IMDG). Subsidiary risk: None allocated Packing Group: None allocated Hazchem Code: None allocated 2. COMPOSITION / INFORMATION ON INGREDIENTS Product Name: “Air Repair” 7D-A SUBSTANCE NAME Proportion

Air Repair contains no harmful substances above the required approval limits as defined by the relevant authorities, in the countries in which it is marketed. The specific chemical identities of the ingredients of this mixture are considered, by Odour Control Systems ODOUR CONTROL SYSTEMS INTERNATIONAL LIMITED Page 1 of 5

CAS Number

International Limited, to be TRADE SECRETS and are withheld in Accordance with the provisions of paragraph 1910.1200 of Title 29 of the Code of Federal Regulations. NOTE: “AIR REPAIR” 7D-A super concentrate is diluted with fresh clean water before use. See Manual for dilution rates. 3. HAZARD IDENTIFICATION Not classified as hazardous. Hazard Category: None allocated. ACUTE HEALTH EFFECTS Swallowed: Harmless, however may cause some irrigation Eye: May cause irritation to the eyes, with effects including: tearing and blurred vision. These effects are regarded to be of a transient (temporary) nature and no long-term injury is anticipated. Skin: Patch tests undertaken for dermal sensitivity showed no sign of irritation Inhaled: No known effects and is considered non toxic Chronic: Not known to be harmful 5. FIRST AID MEASURES Swallowed: If swallowed, DO NOT induce vomiting. If victim is conscious give water. If sickness persists transport to hospital or doctor. Eye: If material is splashed into eyes, immediately, flush with plenty of water for 15 minutes, ensuring eyelids are held open. If irritation persists transport to hospital or doctor. Skin: If material is splashed onto the skin, remove any contaminated clothing and wash skin thoroughly with water and soap if available. If irritation persists transport to hospital or doctor. ODOUR CONTROL SYSTEMS INTERNATIONAL LIMITED Page 2 of 5

Inhaled: Move victim to fresh air. Apply resuscitation if victim is not breathing - If trained personnel available administer oxygen if breathing is difficult. First Aid Facilities: Eye wash fountain, safety shower and normal washroom facilities. Advice to Doctor: Treat symptomatically. 5. FIRE FIGHTING MEASURES Fire/Explosion Hazard: None Hazardous Decomposition Products: None Fighting Procedures: Fire fighters to wear Self-contained breathing apparatus (SCBA) in confined spaces, in oxygen deficient atmospheres. Full protective clothing is also recommended. Extinguishing Media: Use extinguishing media suitable for surrounding fire situation. Flammability This material is not a flammable or combustible liquid. 6. ACCIDENTAL RELEASE MEASURES Material may be slippery when spilt. Walk cautiously. Ventilate area. Wear protective equipment to prevent skin and eye contact, as outlined under personal protection in this MSDS. Bund area using sand or soil - to prevent run off into drains and waterways. Use absorbent (soil, sand, vermiculite or other inert material). Collect and seal in properly labelled containers for disposal. Remainder of material can be washed to drain with plenty of water. 7. STORAGE AND HANDLING Store in a cool place and out of direct sunlight. Keep containers closed, when not using the product. Store in original packages as approved by manufacturer. 8. EXPOSURE STANDARDS / PERSONAL PROTECTION Exposure Standards *************************** No exposure standards have been adopted for this product. Engineering Controls Maintain adequate ventilation at all times. In most circumstances natural ventilation systems are adequate unless the material is heated, reacted or otherwise changed in some type of chemical reaction, then the use of a local exhaust ventilation system is recommended. Personal Protection Equipment ODOUR CONTROL SYSTEMS INTERNATIONAL LIMITED Page 3 of 5

CLOTHING: No special protection. GLOVES: PVC, natural rubber or neoprene. EYES: Chemical goggles or face shield to protect eyes. RESPIRATORY PROTECTION: None required 9. PHYSICAL AND CHEMICAL PROPERTIES Appearance: Liquid, light straw in colour. Perfumed to suit. Boiling Point: 1000 Celsius. Vapour Pressure: Essentially zero. Specific Gravity: 1.154 PH: 5.5 – 6.8 Stability: Stable Incompatibilities: Incompatible with most acids Flash Point: Above 62 degrees Celsius (open cup). Flammability Limits: Not Flammable. Solubility in Water: Miscible.

10. STABILITY AND REACTIVITY STABILITY: Stable under normal conditions of use. HAZARDOUS DECOMPOSITION PRODUCTS: None HAZARDOUS POLYMERIZATION: Will not occur. INCOMPATIBILITIES: Strong acids. CONDITIONS TO AVOID: Incompatibles. 11. TOXICOLOGICAL INFORMATION

RISK PHRASES None allocated. SAFETY PHRASES None allocated. ODOUR CONTROL SYSTEMS INTERNATIONAL LIMITED Page 4 of 5

12. ECOLOGICAL INFORMATION Biodegradable and Non-persistent. 13. DISPOSAL CONSIDERATIONS Dispose of container and unused contents in accordance with federal, state and local requirements. 14. TRANSPORT INFORMATION UN Number: None allocated Proper Shipping Name: “Air Repair” 7D-A Dangerous Goods Class: Not classified as a Dangerous Good according to the UN, DOT (US), IACO (IATA) or IMO (IMDG). Subsidiary risk: None allocated Packing Group: None allocated Hazchem Code: None allocated Not classified as a Dangerous Good according to the UN, DOT (US), IACO (IATA) or IMO (IMDG). 15. REGULATORY INFORMATION Poison Schedule: None allocated 16. OTHER INFORMATION Contact Point: Technical Manager Tel: +649 27 11 054 Information for this material safety data sheet was obtained from sources considered technically accurate and reliable. While every effort has been made to ensure full disclosure of product hazards, in some cases data is not available and is so stated. Since conditions of actual product use are beyond control of the supplier, it is assumed that users of this material have been fully trained according to the mandatory requirements of Worksafe. No warranty, expressed or implied, is made and supplier will not be liable for losses, injuries or consequential damages that may result from the use of or reliance on any information contained in this form End of MATERIAL SAFETY DATA SHEET

ODOUR CONTROL SYSTEMS INTERNATIONAL LIMITED Page 5 of 5

Odour Management Plan

Odour Management Plan

Suggest Documents

Odour Management Plan - MAFIADOC.COM

H4 Odour Management - WAMITAB

H4 Odour Management - WAMITAB

H4 Odour Management

H4 Odour Management - Sinia

H4 Odour Management - Organics Recycling Group

Impaired odour discrimination on desynchronization of odour ...

Change Management Plan Change Management Plan Workbook ...

H4 Odour Management - how to comply with your ... - Gov.uk

12objective odour measurements

Odour of Chrysanthemums

Wound odour: principles of management and the ... - CliniMed, Ltd.

Management Plan - Stadt Regensburg

Network Maintenance Management Plan

Project Management Plan Example

ChemiCals management Plan

MY PAIN MANAGEMENT PLAN

Odour air demopages

Management Plan

CM--Classroom Management Plan

Music Classroom Management Plan

management plan

Management Plan - KZN Wildlife

5310 State Management Plan