highlight some such treatment processes which enable sewage water to be used as Boiler .... Source: National Academy of .Sciences ..... Garg. S. K. 'Sewage Disposal and Air Pollution Engineering', Ninth Edition, Khanna. Publishers. 4.
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RECYCUNG SEWAGE WATER FOR BOILER FEED PURPOSES Dr. R. K. Singh
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Lecturer, DepartmenAbstract : Department of Civil Engineering R I. T. S. Pilani, Rajasthan - 333 031
P.V. S. Syarn Undergraduate Student Civil Engineering RI.T.S. Pilani Rajasthan - 333 031
Abstract Recyded Sewage water has many applications. Using it as boiler feed water is one such application. Boiler feedwater quality requirements are stringent. To meet these, sewage water needs very thorough advanced treatment. In this paper, an attempt has been made to highlight some such treatment processes which enable sewage water to be used as Boiler feedwater. The treatments are broadly classified as external and internal depending on their location of treatment (inside or outside the boiler). The treatment is meant for scale and q)rrosion control, respectively achieved chiefly by water softening thrugh H-Na cation exchange process and dissolved gas removal by physical and chemical means.
Keywords: Sewage water, Boiler feedwater, HNa cation exchange softening, Silica removal, Oxygen Scavengers.
disposingintoriversstreams etc. This sewagewater upon further treatment
or recyclingcan be used to serve
many other purposes. One such vista where (recycled) Introduction sewagewater can be used beneficially In most of the medium and large sized is in Boilers, as Boiler feedwatef. Boilers are devices used for cities in India, Sewage water is given secondary level treatment before transfromingliquidwater to steam by 19 Journa] of the IPRE, India, V0] 1997, No 2
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--- ---heating the water. The sewagewater which will be usedasboiler feedwater shouldbetreatedconsiderablysothat it has the lowest harness., alkalinity, sulphates,silicaand suspendedsolids, to avoid scaling and corrosion in boilers.".. The boiler water
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insidebyadditionbychemicalswhich react inside and prevent scaling, corrosion and foaming. 2. EXTERNAL TREATMENT
Thethreebasictypesof processes, that can be carried out in external treatment of sewagewaterare: requirements are listed in table 1. 1. Suspended solids removal Treatment (recycling) of sewage 2. Dissolvedgas removal water can be classified as . 3. Water softening External Treatment :- Sewage 4. Silicaremoval water composition is altered before Table 2 showstypical constituents it enters the boiler. . and their concentrations in Municipal Internal Treatment:- Water treated wastes after secondary treatment.
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20 Journal of the IPRE, India, Vol 1997, No 2
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'(';(BLE f: BlOLER WATER RECOMMEN~A TlO~S AT INCREASING PRESSURES . ".....'".....""'-'...... . PH u..."n ." C Cln .L'.J
'-
99 20 99
-99 >99 55 94 99
99 68 43 99 96
4-6 2 Not Available
Formaldehyde, Hydrogen Peroxide Sodium Hypochlorite >99
32 Journal ofthe IPHE, India, Vol 1997, No 2
Not Available
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CONCLUSIONS
alsohelp controlpollutioncauseddue to sewage water disposal into the he recycledsewage water after the water streams. xternal and internal treatment >fOcesseswill be fit to be used as The treatment processes discussed ~edwater for boilers to produce in the paper are some of the possible team. These methods exploit the processes for treating water. Since otential of sewage. to the maximum this is a new vista to explored, more xtent, conservingenergy in form of work shouldbe done in thisdirection. :wing precious raw water used in Better treatment processes shouldbe oilers. This water can now be used determined and their applications Jr other purposes. Moreover it may established. .
~eferences : 1.
Water and Treatment: A Hand Book of Public Water Supplies", Prepared by the American Water Works Association, Inc., Third Edition, Mc Graw Hill Book Company.
2.
James. C. Lamb., 'Water Quality and Its Control', John Wiley and Sons.
3.
Garg. S. K. 'Sewage Disposal and Air Pollution Engineering', Ninth Edition, Khanna Publishers.
4.
Nikoladze. G., D. Mints, A. Kastalsky, 'Water Treatment for Public and Industrial Supply', Mir Publishers, Moscow.
5. Charles. C. Patton. ' AppliedWater Technology',FirstEdition,CampbellPetroleum Series.
mmal of the IPHE, India, Vol 1997, No' 2
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