Characteristics of Activated Sludge in. Municipal Wastewater Treatment. Plants, China. Hui Lil, Zhijian Zhangl*, Hang Wang, Xin Xul, Yuan Lin', Jianying Zhang', ...
Biological Phosphorus Removal Performance and Relevant Microorganism Characteristics of Activated Sludge in Municipal Wastewater Treatment Plants, China 2 Hui Lil, Zhijian Zhangl*, Hang Wang, Xin Xul, Yuan Lin', Jianying Zhang', Zhu Jun
ABSTRACT: Municipal wastewater discharge is threatening the ecological security of the local water environment. This study investigated the field process performance and microorganism characteristics of enhanced biological phosphorus removal (EBPR) in municipal wastewater treatment plants (WWTPs) in China. The results showed that three WWTPs met the required criteria of phosphorus for discharge (:51 mg1L), but with a low level of Accumulibacter (6.4 to 3.8%, on average) and a relatively high level of Competibacter (3.2 to 9.1%) in sludge. The phosphorus release and uptake rates were varied from 0.224 to 7.770 mg/gVSS.h and 0.386 to 7.901 mg/gVSS.h, respectively. Denitrifying polyphosphate-accumulating organisms were estimated to be 28.2% of the polyphosphate-accumulating organisms. Sludge characteristics (phosphorus release and uptake rates) were positively correlated with the abundance of Accumulibacter and negatively correlated with the proportion of Competibacter.Moreover, the lower the ratio of anaerobic phosphorus/acetate (e.g., 0.496) is, the more abundant the Competibacter would be. Further discussion on an improvement strategy for these WWTPs for EBPR should be comprehensively based on the data of periodic investigations on field operation, sludge activities, and microbial populations. Water Environ. Res., 83, 594 (2011). KEYWORDS: enhanced biological phosphorus removal, batch tests, Accumudibacter, Compelibacter, influent composition, denitrifying polyphosphate-accumulating organisms. doi: 10.2175/10614301OX12851009156682
Introduction Taihu Lake, located in the Yangtze River delta, is being threatened by excessive total phosphorus (TP) concentrations up to 0. 1 to 0.2 mg/L (Ye et al., 2007), resulting from complex sources of pollution because of the fast development in agriculture, industry, and urban construction. The exports of
SInstitute of Environmental Sciences, Zhehiang University, HangZhou, China. 2 University of Minnesota, Department of Biosystems and Agricultural Engineering, Southern Research and Outreach Center. Waseca, Minnesota. * Institute of Environmental Sciences, Zhehiang University, 2 6 8gh KuanXian Avenue, HangZhou, China. 310029; e-mail: zhangzhijian@ zju.edu.cn. 594
nutrients (e.g., nitrogen and phosphorus) and organic materials into the Qiantang River directly cause deterioration in downstream water quality (i.e., Qiantang bay and the associated region of the East China Sea). East Tiaoxi is located between the Taihu Lake and Qiantang River, belonging to the Pan-Taihu Lake basin, which is an important water source for the cities of Huzhou and Hangzhou. The discharge of municipal wastewater, containing a considerable amount of nutrients and organic matter without adequate treatment, into the surface waters could accelerate water eutrophication. Therefore, it is urgent for the regional municipal wastewater treatment plants (WWTPs) to meet the criteria of effluent discharge from level B (e.g., chemical oxygen demand [COD] -
202
1.5
% 201
0Z
1.3
E 200
S199 S198 O
E
197 196 195
1.0
CA 0.
0.8
0.
0.5 0
15
65
85
105
125
145
205
265
Time (min)
WWTP-SS
65 C2 63
0.8 CIO 0.7 en C)b 0.6
-A- Acetate -Phosphorus
5€>60
0.5 0.4 0.3
-- 58 S55 .
53
50
0
0.2
&
< 48 45
0.1.
0
0
0
15
30
65
85
105
145
175
265
Time (min)
Figure 1-Profile of soluble phosphorus (diamond) and acetate (triangle) in reaction solution during the anaerobic tests. Units in the y-axis are defined as mg acetate or phosphorus in solution per g VSS in mixed liquor. Fluorescence In Situ Hybridization Analysis.
For quantifi-
cation of PAOs and GAOs among the microbial communities, fluorescence in situ hybridization (FISH) analyses were performed as described by Manz et al. (1995). Approximately 0.1 mL sludge for each slide was fixed in 4% paraformaldehyde-phosphatebuffered-saline (PBS) solution (137 mM NaCI, 8.1 mM Na 2HPO 4 , 2.68 mM KCI, and 1.47 mM KH 2 PO4 , at pH 7.2) for 2 hours at 4'C. The fixed sludge samples were washed twice in PBS, resuspended in PBS-ethanol solution (1:1, vol/vol), and stored at -20'C. The FISH probes used in this study were Cy5-labelled EUBMIX (comprising equal amounts of probe EUB338, EUB338-cx, and EUB338-P3) for all bacteria; 6-FAM-labelled PAOMIX (comprising equal amounts of probe PA0462, PA065 1, Water Environment Research, Volume 83, Number 7
Li et al, and PAO846) for BetaproteobacteriaAccuinulibacter spp.; and Cy3-labelled GAOMIX (comprising equal amounts of probe GA043 1, GA0989, and GB-G2) for Gaminaproteobacleria Competibacterspp. (Takara, Japan) (Carvalho et aL., 2007). The hybridization process was performed at 46°C for 2.5 hours in a hybridization oven. The FISH preparations were visualized with a confocal scanning laser microscope (Leica TCS SP5, Solms, Germany). Quantifications of population distributions were carried out using the MATLAB image processing toolbox (The Mathworks, Natick, Massachusetts) using the method of L6pezVfi-zquez et al. (2007). Eight-bit images for each of the color channels (red for EUB, green for PAO, and blue for GAO) were converted into binary format using direct thresholding at a graylevel determined, where pixels with value below the threshold level represented the background. Image coverage was computed by dividing the number of pixels corresponding to the object with the total number of pixels of the image. The area containing the Cy3- and 6-FAM labeled cells were quantified as a percentage of the area of Cy5-labeled cells within each image. The final quantification result was expressed as a mean percentage obtained from 10 images analyzed. The results reflect the average fractions of Accuinulibacter and Competibacierof all biomass. Results and Discussion Status of Wastewater Treatment Plant Operation. The selected parameters of process configurations of the three treatment plants in this survey are shown in Table 1. Despite the different configurations (WWTP-QG operating A/A/O-Phoredox process, and WWTP-XC and WWTP-SS adopting the modified UCT process [Table 1]), the investigated plants were designed with the functional EBPR process by sequentiaLly exposing liquid to cyclic anaerobic, anoxic, and aerobic stages in order. The implementation of a separate predenitrification tank was found in WWTP-QG only, so that intrusions of oxygen, nitrate, or nitrite in anaerobic tanks were effectively prevented. That special design could reduce the consumption of VFAs by ordinary heterotrophs during the anaerobic stage (L6pez-VAizquez et al., 2008) and preserve adequate carbon source for the following aerobic stage. The ratio of indtustrial wastewater to total influent varied from 25 to 55%, which was larger than those of developed countries, such as the Netherlands (no more than 25%) (L6pez-V,Azquez et al., 2008). The pH in the anaerobic tank varied from 6.5 to 7.3, and the ratio of MLSSIVSS was highest (1-.92) in WWTP-SS and lowest in WWTP-XC (.52). The ratios differed slightly among the three WWTPs, but the MLSS concentration varied from 1280 to 6240 mg/L. During the investigation, a certain amount of sludge in the anaerobic zone of WWTP-XC and WWTP-SS was floating without activity-thus non-functioning. The summary of the compiled data of each operation for the period of study is shown in Table 2 and included the following: (1) Mean CODINF and BOD5INF concentrations were 306 mg/L and 85.8 mg/L, and the ratio of CODINF/BOD51NF was in the range 2.79 to 3.00, which was slightly higher than the results form the developed countries (2.64 ± 0.56); (2) Average FlPr[Nr to VFAINr ratio was 0.t13±0.151; (3) TPINF of inflow was 3.089 rng/L. TPINI was significantly lower than found in developed countries, which were reported to be approximately 10 mg/L in the United Kingdom and Netherlands municipal wastewater (L6pez-VAzquez et al., July 2011
WWTP-QG
16 14 12 crJ 10 09 >8 0 6 4 24 Ci 2 0 0 0
10
20
30
50
-.--
Anoxic Phosphorus
90
120 150
180 270
Time (min) 14
cj3
1.2 1.0 0,8 0.6
0 0
0
0.4 0.2 0.0 0
15
30
45
65
85
105
125
145
175
205
265
Time (min)
bi)
0
4-
WWTP-SS
1.7 1.6 1.5 1.4 1.3 1.2 1.1 1
"---AerobicPhosphorus -.---
Anoxic Phosphorus
..
i-.-
0.9 0.8 0
15 30
45
65
85 105 125 145 175 205 265
Time (min) Figure 2-Profile of soluble phosphorus in reaction solution during the aerobic (triangle) and anoxic (square) tests. Unit in the y-axis is defined as mg P in solution per g VSS in mixed liquor. 2008; Manyumba et al., 2009), and approximately 5 mg/L in Korea (Kim et al., 2009); and (4) Mean TPINF/VFAINF was 0.462 ± 0.618. There are two possible reasons for the low concentration of TPINF and biodegradable organic materials in influent. First, overloading of industrial wastewater (approximately 25 to 55% of the total) (for the sake of reducing treatment costs) to the local municipal wastewater system deteriorated the performances of WWTPs, as a result of the involvement of poor biodegradable organic matters in chemical industrial wastewater (e.g., printing and dyeing) and some toxic compounds, such as heavy metals in rnetallurgic industrial wastewater, which could impair the activity 597
Li et al.
Table 2-Selected physical-chemical properties of influent and effluent of the investigated WWTPs.* Parameters Influent parameters BOD5 (mg/L) CODcr (mg/L) CODcr/BOD 5
VFA (mg/L) HAc (mg/L) HPr (mg/L) Total phosphorus (mg/L) PO 4 3 -- P (mg/L) TP/VFA (mg/mg) Effluent parameters BOD 5 (mg/L) CODer (mg/L)
Total phosphorus (rmg/L) PO43 -_P (mg/L)
WWTP-QG 102 290 2.84
25.3 22.9 2.4 3.866 3.613 0.153 10.8 140
0.302 0.234
WWTP-XC (91±32.2) 253 (246±44.2) 2.79
2.6 2.6 Not determined 3.054 (2.17±0.47) 2.631 1.175 13.2 (15.0±2.9) 120 (35.8±9)
0.489 (0.26±0.08) 0.441
WWTP-SS (125±63.5) 375 (406±98.5) 3.00
38.2 26.9 11.3 2.345 (1.661±0.489) 2.056 0.061 15.7 (3.5±0.6) 90 (38±8)
0.953 (0.804±0.108) 0M897
HBr and HVr were below detection limitations in this paper. Data in brackets were collected from WVVTPs representing the properties during investigation month. of microorganisms in sludge (Saunders et al., 2003). Second, it may have something to do with the local diet and living patterns, because Chinese eat more vegetables than meat, resulting in low phosphorus content in influent. Overall, the inflow of WWTP-QG was relatively stable, as the industrial source accounted for 25% of the total. However, the economic prosperity of Changxing and Deqing depends on the rapid development of the printing, dyeing, and chemical industries, which contributed a high fraction of nonbiodegradable organic materials to total COD and low content of total phosphorus (Table 2). The concentrations of COD in effluent reached the range 90 to 140 mg/L, which highly exceeded the discharge limits, posing a great threat to the regional water quality. This may be attributed to the high fraction of industrial wastewater input, leading to a low availability of carbon source for the EBPR microorganisms. The highest phosphorus removal efficiency (92.2%) was found in WWTP-QG, where the concentration of TPEFF reached 0.302 mg/ L; however, WWTP-SS showed the poorest running phosphorus removal efficiency (59.4%), accompanied by a TPEFF concentration of 0.953 mg/L. Therefore, both WWTP-QG and WWTP-XC met level I (A) for discharge, in terms of phosphorus, and made positive contributions to the control of eutrophication in the Qiantang River and southwest of Taihu Lake. The TPEFF concentration of WWTP-SS met the present standard of level I (3), but was far beyond the standard of level I (A). It is worth noting that, even though all TPEFF concentrations were below 1.0 mg/L, the phosphorus removal efficiencies were lower than those reported in developed countries (mostly beyond 90%) (Kuba et al., 1997; L6pez-Vizquez et al., 2008; Manyumba et al., 2009), indicating that the low TPIrN concentration might be insufficient for PAOs to perform, and/or some Competibacterswere probably dominant in those tested WWTPs. Laboratory Investigation on Enhanced Biological Phosphorus Removal Activity. Anaerobic Acetate Uptake and Phosphorus Release. All three WWTPs showed HAc uptake and phosphorus release simultaneously in the anaerobic batch tests (Figure 1). With the hydrolysis of polyphosphate, inorganic phosphate was released to provide the energy for acetate spiking, resulting in the increase of P043--P concentration and decrease of 598
HAc concentration in water, The HAc was transformed into PHA to maintain the growth of cells and metabolic activity (Smolders et al., 1995). However, there was a clear difference in the time required for WWTP-QG, WWTP-XC, and WWTP-SS to finish the anaerobic metabolic process. The WWTP-QG and WWTP-XC stopped HAc uptake at 180 and 205 minutes, respectively, while WWTP-SS showed anaerobic metabolic trends until 270 minutes and had the least amount of HAc uptake and phosphorus release. Compared with the data in Table L, the anaerobic HRTs in the three WWTPs were too short to ensure full assimilation of HAc and phosphorus release, which could impair the following anoxic and aerobic phosphorus uptake. The corresponding parameters of the kinetic and stoichiometry process reaction are summarized in Table 3. The HAc uptake rates of WWTP-GQ and WWTP-SS were 21.84 and 15.25 mg/gVSS.h, in the range 14.0 to 48 mg/gVSS.h according to the reported data (L6pez-VAzquez et al., 2008); however, the data of WWTP-XC was much lower (6.25 mg/gVSS.h), as a result of the lowest concentration of HAc in the influent, which could limit the growth of PAOs. The phosphorus release rate has been used to compare the activity of EBPR (Stephens and Stensel, 1.998; Zilles et al., 2002). Table 3 shows that WWTP-QG achieved the best performance for activated sludge, as the highest level of phosphorus release rate was observed (7.770 mgP/gVSS.h), while samples from WWTP-XC and WWTP-SS showed poor performance regarding phosphorus release (1.932 and 0.224 mgP/ gVSS-h, respectively)., Nevertheless, the investigated values of anaerobic phosphorus release rates were lower than those of similar reports in the leading countries (Table 3). A previous study concluded that the anaerobic phase required at least 25 mg/L of readily biodegradable organic material (e.g., VFAs) to initiate phosphorus release (Henze et al., 1996). Thus, it could be conclutded that VFAs in WWTP-XC were too low to stimulate PAO to function, while WWTP-SS belonged to a phosphoruslimited system, because the COD/phosphorus and BOD/phosphorus ratios were more than 40 and 20, according to Manyumba et al. (2009). Therefore, phosphorus is not subsequently available for PAOs to replenish their intracellular polyphosphate pools (one of the main energy sources) after the phosphorus-release process, Water Environment Research, Volume 83, Number 7
Li et al.
Table 3-Summary of the anaerobic-anoxic-aerobic activity tests results carried out with activated sludge from the different WWTPs.
WWTPs
WWTP-QG WWTP-XC WWTP-SS Reported data Hardenberg (L6pezV6zquez et al., 2008) Waarde (L6pez-Wzquez et al., 2008) Hotten (Kuba et al., 1997) El (He et al., 2008)
HAc uptake rate (mg/gVSS.h)
21.84 6,25 15.25
Phosphorus release rate (mg/gVSS.h)
Anaerobic P/HAc (mg/mg)
7.770 1,932 0.224
7.901 0.626 0.386
21.9
17.4
0.38
19.2
14.0 48.0 N,R,
13.6 13.0 11.1
0.45 0.50 0.48
6.3 13.0 1.1
inhibiting the biological phosphorus removal process for WWTPSS. According to the proposed stoichiometry of EBPR, at pH 7, the theoretical anaerobic P/HAc ratio should be in range 0.4 to 0.6 (Filipe et al., 200.1; Smolders et al., 1994). The samples, except WWTP-QG, exhibited lower ratios than the reported, especially for WWTP-SS, indicating the activity of GAOs that were able to assimilate acetate anaerobically, but without polyphosphate transformation, leading to a decreased P/HAc ratio. Aerobic and Anoxic Phosphorus Uptake Batch Tests. Figure 2 shows the profile of phosphorus uptake in the aerobic and anoxic batch tests. In the following aerobic period, the concentration of phosphate in water decreased with time, indicating that PAO used 02 as an elector acceptor to take up inorganic phosphorus and store it in the form of intracellular polyphosphate. The obvious difference here is the time when WWTP-QG, WWTP-XC, and WWTP-SS stopped the aerobic phosphorus uptake process, which was at 120, 145, and 170 minutes, respectively, showing the disadvantageous trends similar to the phosphorus release rates during the anaerobic process (Table 1). Consistent with anaerobic performance, WWTP-QG sludge displayed relatively better phosphorus uptake activity than those of the other two plants, with the aerobic phosphorus uptake rate of 7.9 mgP/gVSS-h (Table 3). Meanwhile, the aerobic phosphorus uptake rates of the WWTP-XC and WWTP-SS sludge were lower than 1.0 mgP/gVSS'h, indicating that very few PAOs were present in the two plants. The results concerning the phosphorus uptake rate were worse than those of reported studies (Table 3), showing poorer EBPR activity in our region. By summarizing the kinetic and stoichiometry parameters (at stages of anaerobic, anoxic, and aerobic) in Table 3, it is worth noting that the anaerobic HAc uptake and phosphorus-release rate had a significant correlation with the aerobic phosphorus uptake rate, because good anaerobic performance provided enough PHA and energy for the following anoxic and aerobic phosphorus uptake (Li et al., 2008). Anoxic phosphorus uptake was observed in WWTP-QG sludge only, illustrating the presence of DNPAOs in the biomass. The WWTP-XC and WWTP-SS displayed no anoxic phosphorus uptake, which meant that DNPAOs barely occurred in the plants or at least the amount of DNPAOs activity was far below the detection limits. On the other hand, the anoxie phosphorus uptake rate of samples from WWTP-QG was 2.23 mgP/gVSS.h, which was smaller than the rates of reported WWTPs displaying anoxic July 2011
0.500 0.204 0.034
Aerobic phosphorusuptake rate (mg/gVSS.h)
Anoxic phosphorus-uptake rate (mg/ gVSS.h)
Anoxic/aerobic phosphorusuptake rate (%)
2.231 0 0
28.2 0 0
5.9
31
0 6 Not reported
0 50 Not reported
phosphorus uptake activity (3.3 to 6.0 mgP/gVSS.h, Table 3). From the comparison of phosphorus uptake rates between the aerobic and anoxic conditions, the relative proportion of DNPAOs to PAOs was estimated (Kuba et al., 1997) to be approximately 28.2%. It might be the relatively long anoxic HRT that provided more chances of stimulating the formation of denitrification enzymes in PAO (Zeng et al., 2003), which resulted in WWTPQG displaying the feature of anoxic phosphorus uptake. Quantification of Microbial Populations. Quantification of the different microbial populations (Accumulibacter and Competibacter) for the three different WWTPs is presented in Figure 3, and these two group of microbes were visualized in a FISH map in Figure 4. Accumulibacter, on average, comprised approximately 4.7% of the total biomass and Competibacterapproximately 5.9% (both as EUB). Regarding the Accumulibacter and Competibacter fractions in sludge, two different trends were observed. In WWTP-QG, Accumulibacter (6.4%) obviously surpassed Comptibacter (3.2%). However, in WWTP-XC and WWTP-SS, Competibacter overtook Accumulibacter, especially in WWTP-SS, where Coanpetibacter accounted for 9.1% of the total biomass. Lower fractions of Accunutlibacter were found compared with the previous full-scale reports-5 to 22% by Kong et al. (2004), 7 to 17% by Chua et al. (2006), 5 to 20% by Gu et al. (2008), and 9 to 24% by He et al. (2008), demonstrating once again that WWTP-XC and WWTP-SS possessed marginal phosphorus removal efficiency by EBPR. Competibacter, on the other hand, was in the range of previous data (0 to 20%)-0 to 6% by Tykesson et al. (2006), 1 to 12% by Kong et al. (2004), 0 to 20% by Gu et al. (2008), and 0.4 to 2.9% by L6pez-V6zquez et al. (2008). By integrating the data in Tables 2 and 3, it can be inferred that the conventional biological phosphorus process was prevalent in WWTP-XC and WWTP-SS. Moreover, the rates of anaerobic phosphorus release and aerobic and anoxic phosphorus Uptake obtained from the batch tests of EBPR activity correlated positively with the abundance ratio of AccunulibacterIEUB and negatively with the abundance ratio of CompetibacterlEUB in this study, demonstrating that Accumulibacter are functional microorganisms in EBPR, while Competibacterwould deteriorate the system. A liquid temperature below 20"C appears to be more favorable for PAOs than GAOs (L6pez-V:izquez et al., 2009). The high 599
Li et al.
I0 w
"-
•' 8
]0 Accumulibacter 0 Competibacter
=a 7 a' 6 (05 E ,O 4
D
E
Cc,
WVVTP-QG
WWTP-XC
WWTP-SS
Figure 3-Fractions of PAOs (Accumulibacter) and GAOs (Competibacter) populations in the WWTPs of the batch tests related to total biomass (as EUB).
temperature (approximately 30'C) during the summer season investigation might be one essential factor inducing GAO growth in WWTP-SS, while the low temperature (approximately 18*C) in early spring possibly enhanced the activity of PAOs for WWTPQG. On the other hand, an appropriate phosphorus/HAc ratio (0.40 mgP/mgHAc) led to a low GAO fraction (0.4 ± 0.1%) (L6pez-Vdzquez et al., 2008). A ratio of phosphorus/HAc that was too high or too low (e.g., WWTP-XC = 1. 175 mgP/mgHAc and WWTP-SS = 0.061 mgP/mgHAc) would negatively affect the phosphorus removal efficiency of EBPR, because either limited carbon reduced PAOs metabolism or excessive carbon favored GAO growth, which caused Accumulibacter to account for 3.9% of total biomass in WWTP-XC and the highest fraction (9.1%) of Competibacter to EUB in WWTP-SS. Implications for Enhanced Biological Phosphorus Removal Improvement. Based on the present conditions, three operational strategies are recommended for the improvement of EBPR performances in our municipal WWTPs. First, decreasing the amount of industrial wastewater to the municipal WWTPs is especially important for the growth of functional microorganisms in the activated sludge system, which can improve the availability of readily biodegradable organic matter. In addition, the application of separate pre-denitrification is required to separate PAOs/non-PAOs from nitrifiers (Kuba et al., 1997). In the predenitrification system, the sludge entering the anoxic tank had a maximum PHA content allowing for denitrifying and phosphorus uptake. This favors the prime use of PHA-COD for DPAOs and minimizes aerobic PHA oxidation. Finally, special attention to the influent composition and pH control is recommended, especially in the summer season, because temperature has a significant effect on the competition between PAOs and GAOs for growth. Obviously, the efficiency and effectiveness of EBPR for fullscale WWTPs are greatly influenced by the multi-factor process and the associated parameter-interaction bio-course. Therefore, the improvement strategy for these WWTPs for EBPR should be further discussed comprehensively, based on the data of periodic investigations on field operation, sludge activities, and microbial populations. 600
Figure 4-In situ hybridization of activated sludge samples from (a) WWTP-QG and (b) WWTP-SS with probes.
Conclusions The investigation of EBPR in municipal WWTPs in the Northern part of Zhejiang province was conducted based on sludge characterization and microbial population distribution. The following conclusions have been drawn from the performance tests and the quantification of microbial communities. The TPEFF in WWTP-QG, -XC met the required national discharge standard of level I (A) (--0.5mg/L). However, it was a great challenge for WWTP-SS to meet this standard, as a result of the poor performance of the phosphorus release (0.224 mg/ gVSS.h) and uptake (0.034 mg/gVSS-h) rates in batch tests, Water Environment Research, Volume 83, Number 7
Li et at. showing poor EBPR activity. In the meantime, the anaerobic phosphorus/HAc ratio (0.204 and 0.034 for WWTP-XC and WWTP-SS) below the theoretical value (0.4 to 0.6) indicated the presence of GAOs competing for a carbon source. The number of Accumulibacter was the highest in WWTP-QG (6.4%) and the lowest in WWTP-SS (3.8%), and the number of Competibacter accounted for 9.1% of the total biomass in WWTP-SS and 3.2% in WWTP-QG. Therefore, the anaerobic phosphorus release and aerobic phosphorus uptake rates were positively correlated with the fraction of Accumulibacter to the total biomass and negatively
correlated with the proportion of Competibacter. Further exploration on an improvement strategy for these WWTPs for enhanced removal of biological phosphorus is needed by periodic data collecting of field running, sludge activities, and microbial populations, in addition to reducing the proportion of industrial wastewater in influent and applying a separate predenilrification tank. Credits The authors thank the Natural Science Foundation of China (Beijing) (40701162NY506215), Zheijiang Science and Technology Program (Hangzhou, China) (project 2009C33060/ 20091633F06), and the Fundamental Research Funds for the Central Universities (Beijing, China) (2009QNA6013) for funding this project. Submitted for publication September 21, 2009; revised manu,scrilt submitted October 9, 20.10; accepted for publication December 8, 2010.
References American Public Health Association; American Water Works Association; Water Environment Federation (1998) Standards Methods for the b.ramination of Water and Wastewater, 20th ed.; American Public Health Association: Washington, D.C. Brdjanovic, D.; Van Loosdrecht, M. C. M.; Versteeg, P.; Hooijmans, C. M.: Heijnen, J. J. (2000) Modeling COD, N and P Removal in a FullScale WWTP Haarlem Waarderpolder. Water Res., 34, 846-858. Burow, L. C.: Kong, Y. H.; Nielsen, J. L.; Blackall, L. L.; Nielsen, P. H. (2007) Abundance and Ecophysiology of Defluviicoccus spp. Glycogen Accumulating Organisms in Full-Scale Wastewater Treatment Processes. Microbiol-SGM, 153, 178-185. Carvalho, G.; Lemos, P. C.: Oehmen, A.; Reis. M. A. M. (2007) Denitrifying Phosphorus Removal: Linking the Process Performance with the Microbial Community Structure. Water Res,, 41, 4383-4396. Chen, Y. G.; Randall, A. A.; McCue. T. (2004) The Efficiency of Enhanced Biological Phosphorus Removal from Real Wastewater Affected by Different Ratios of Acetic to Propionic Acid. Water Res., 38, 27-36. Chua, A. S. M.; Omuki, M.; Satoh, H.; Mine, T. (2006) Examining Substrate Uptake Patterns of Rhodocyclus-Related PAO.in Full-Scale EBPR Plants by Using the MAR-FISH Technique. Water Sci. TechnoL, 54, 63-70. Filipe, C. D. M.; Daigger, G. T.; Grady, C. P. L. (2001) Stoichiometry and Kinetics of Acetate Uptake Under Anaerobic Conditions by an Enriched Culture of Phosphorus-Accumulating Organisms at Different pHs. Biotechnol. Bioeng., 76, 32-43. Gu, A. Z.; Saunders, A.; Neething, J. B.; Stensel, H. D.; Blackall, L. L. (2008) Functionally Relevant Microorganisms to Enhanced Biological Phosphorus Removal Performance at Full-Scale Wastewater Treatment Plants in the United States. Water Environ. Res., 88, 688-698. Haygarth, P. M.. Jarvis, S. C. (1997) Soil Derived Phosphorus in Surface Runoff from Grazed Grassland Lysimeters. Water Res., 31, 140-148. He, L. J. (2008) Technological Options on Improving Nutrients Removal of Municipal Wastewater Treatment Plants in TaiHu Lake Basin. Construction Sci. Technol., 7, 110--It. July 2011
He, S. M.; Gu. A. Z.; McMahon. K. D. (2008) Progress toward Understanding the Distribution of Accumulibacter Among Full-scale Enhanced Biological Phosphorus Removal System. Microb. EcoL, 55, 229-236. Henze. M.; Harremo6s, P.; Arvin, E.; Jansen, J. I. C. (1996) Chapter 8: Plants for Biological Phosphorus Removal. In Wastewater TreatmentBiological and Chemical Processes, 2nd ed.; Springer Verlag: Berlin, Germany. Kim, D.; Kim, K. Y.; Ryu, H. D.; Min, K. K.; Lee, S. 1. (2009) Long Tenr Operation of Pilot Scale Biological Nutrient Removal Process in Treating Municipal Wastewatec. Bioresour. Technol., 100, 31803184. Kishida. N.; Kim, J.; Tsuneda, S.; Sudo, R. (2006) Anaerobic/Oxic/Anoxic Granular Sludge Process as an Effective Nutrient Removal Process Utilizing Denitrifying Polyphosphate-Accumulating Organisms. Water Res., 40, 2303-2310. Kong, Y. H.: Nielsen, J. L.; Nielsen, P. H. (2004) Microautoradiographic Study of Rhodocyclus-Related Polyphosphate Accumulating Bacteria in Full-Scale Enhanced Biological Phosphorus Removal Plants. Appl. Environ. Microbial., 70, 5383-5390. Kong. Y. H.: Xia, Y.; Nielsen, J. L.; Nielsen, P. H. (2006) Ecophysiology of a Group of Uncultured Gammnaproteobacterial Glycogen-Accumulating Organisms in Full-Scale Enhanced Biological Phosphorus Removal Wastewater Treatment Plants. Entviron. Microbiol., 8, 479489. Kuba, T.; Van Loosdrecht, M. C. M.; Brandse. F. A.; Heijnen, J. J. (1997) Occurrence of Denitrifying Phosphorus Removing Bacteria in Modified UCT-Type Wastewater Treatment Plants. Water Res., 31, 777-786. Li, H. J.; Chen, Y. G.; Gu, G. W. (2008) The Effect of Propionic to Acetic Acid Ratio on Anaerobic-Aerobic (Low Dissolved Oxygen) Biological Phosphorus and Nitrogen Removal. Bioresour. Technol., 99, 4400-4407. L6pez-V6zquez, C. M.; Hooijmans, C. M; Brdjanovic, D.; Gijzen, H. J.; van Loosdrecht, M. M. C. (2008) Factors Affecting the Microbial Populations at Full-Scale Enhanced Biological Phosphorus Removal (EBPR) Wastewater Treatment Plants in the Netherlands. Water Res.. 42, 2349-2360. L6pez-Vgzquez, C. M.; Hooijmans, C. M.; Brdjanovic, D.; Gijzen, H. J.; van Loosdrecht, M. M. C. (2009) Temperature Effects on Glycogen Accumulating Organisms. Water Res., 43, 2852-2864. L6pez-Vszquez, C. M.; Song, Y. I.; Hooijmans, C. M.; Brdjanovic, D.; Moussa, M. S.: Gijzen, H. J.; van Loosdrecht, M. M. C. (2007) Short-Term Temperature Effects on the Anaerobic Metabolism of Glycogen Accumulating Organisms. Biotech. Bioeng., 97, 483495. Manyumba, F., Wood, E.; Horan, N. (2009) Meeting the Phosphorus Consent with Biological Nutrient Removal Under UK Winter Conditions. Water Environ. J., 23, 83-90. Manz, W.; Amann, R.; Szewzyk, R.; Szewzyk, U.; Stenstrom, T. A.; Hutzler, P.; Schleifer, K. H. (1995) In-Situ Identification of Legionellaceae Using 16s Ribosomal-RNA-Targeted Oligonucleotide Probes and Confocal Laser-Scanning Microscopy. MicrobiologySGM, 141, 29-39. Mino, T.; van Loosdrecht, M. C. M.; Heijnen, 1. J. (1998) Microbiology and Biochemistry of the Enhanced Biological Phosphorus Removal Process. Water Res., 32, 3193-3207. Oehmnen, A.; Lemos, P. C.; Carvalho, G.; Yuan, Z. G.; KelUer, J.; Blackall, L. L.; Reis, M. A. M. (2007) Review: Advances in Enhanced Biological Phosphorus Removal: From Micro to Macro Scale. Water Res., 41, 2271-2300. Oehmen, A.; Saunders, A. M.; Vives, M. T.; Yuan, Z. G.; Keller, H. (2006) Competition Between Polyphosphate and Glycogen Accumulating Organisms in Enhanced Biological Phosphorus Removal Systems with Acetate and Propionate as Carbon Sources. J. Biotechnol., 123, 22-32.' 601
Li at al. Ochmen, A.; Yuan, Z. G.; Blackall, L. L. (2005) Comparison of Acetate and Propionate Uptake by Polyphosphate Accumulating Organisms and Glycogen Accumulating Organisms. Biotech. Bioeng., 91, 162168. Saunders, A. M.; Oehmen, A.; Blackall, L. L.; Yuan, Z.; Keller, J. (2003) The Effect of GAOs (Glycogen Accumulating Organisms) on Anaerobic Carbon Requirements in Full-Scale Australian EBPR (Enhanced Biological Phosphorus Removal) Plants. Water Sci. Technol., 47, 37-43. Smolders, G. J. F.; van der Meij, J.: van Loosdrecht, M. C. M.; Heijnen, J. .1. (1994) Model of the Anaerobic Metabolism of the Biological Phosphorus Removal Process: Stoichiometry and pH Influence. Biotechnol. Bioeng., 43, 461-470. Smolders, G. J. F.; van der Meij, J.; van Loosdrecht, M. C. M.; Heijnen, J. J. (1995) A Structured Metabolic Model for Anaerobic and Aerobic Stoichiometry and Kinetics of the Biological Phosphorus Removal Process. Biotechnol. Bioeng., 47, 277-287. Stephens, H. L.; Stensel. H. D. (1998) Effect of Operating Conditions on Biological Phosphorus Removal. Water Environ. Res., 70, 362369.
602
Tykesson, E.; Blackall, L. L.; Kong, Y.; Nielsen, P. H.; Jansen, J. L. (2006) Applicability of Experience from Laboratory Reactors with Biological Phosphorus Removal in Full-Scale Plants. Water Sci. Technol., 54, 267-275. Whang, L. M.; Filipes, C. D. M.; Park, J. K. (2007) Model-Based Evaluation of Competition Between Polyphosphate-and GlycogenAccumulating Organisms. Water Res., 41, 1312-1324. Ye, C.; Xu, Q. J.; Kong, H. N.; Shen. Z. M.; Yan. C. Z. (2007) Eutrophication Conditions and Ecological Status in Typical Bays of Lake Taihu in China. Environ. Monit. Assess., 315, 217-225. Zeng, R. J.; Yuan, Z. G.; Keller, J. (2003) Enrichment of Denitrifying Glycogen-Accumulating Organisms in Anaerobic/Anoxic Activated Sludge System. Biotechnol. Bioeng., 81, 397-404. Zhang, C.; Chen, Y.; Liu, Y. (2007) The Long-Term Effect of Initial pH Control on the Enrichment Culture of Phosphorus- and GlycogenAccumulating Organisms with a Mixture of Propionic and Acetic Acids as Carbon Sources. Chemosphere, 69, 1713-1721. Zilles, J. L.; Peccia, J.; Kim, M. W. (2002) Involvement of RhodocyclusRelated Organisms in Phosphorus Removal in Full-Scale Wastewater Treatment Plants. Appl. Environ. Microbiol., 68, 2763-2769.
Water Environment Research, Volume 83, Number 7
COPYRIGHT INFORMATION
Author: Li, Hui; Zhang, Zhijian; Wang, Hang Title: Biological Phosphorus Removal Performance and Relevant Microorganism Characteristics of Activated Sludge in Municipal Wastewater Treatment Plants, China Source: Water Environ Res 83 no7 Jl 2011 p. 594-602 ISSN: 1061-4303 DOI:10.2175/10614301OX12851009156682 Publisher: Water Environment Federation 601 Wythe Street, Alexandria, Va 22314-1994
The magazine publisher is the copyright holder of this article and it is reproduced with permission. Further reproduction of this article in violation of the copyright is prohibited.
This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sublicensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
