A new modified activated sludge process for treating carbohydrate wastes deficient in nitrogen

AuthorKong, Chan Long
Call NumberAIT Thesis no. 821
Subject(s)Sewage disposal
Sewage--Purification--Activated sludge process
Factory and trade waste
NoteA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand.
PublisherAsian Institute of Technology
AbstractAcid hydrolytic assist was applied to oxidative assimilation process in order to improve the COD removal efficiency and to eliminate the excess sludge disposal problem. From batch studies, it was seen that this modification was feasible. Hydrolyzed sludge did not exhibit any bad effect on the regeneration of sludge in the regenerating phase. A continuous-flow pilot plant of oxidative assimilation process was set up to observe whether the biological solids in the system could be controlled to a desirable level by the hydrolytic assist. The pilot plant was operated with Pepsi Cola waste as the source of carbon, and with a detention time of 4 hours in the feeding aerator. COD removal efficiency was always above 94% in the period of operation. It was observed that the biological solids concentration in the system could be controlled to a desirable range for operation. The excess sludge could be totally oxidized in the system with the aid of hydrolytic assist. The hydrolyzed sludge could be used as nitrogen source for the regeneration of sludge in the regeneration aerator. No bulking sludge and rising sludge had been observed in the period of operation. Sludge settling characteristic was good, average SVI was only 90. The effluent quality was excellent, Filtrate COD was always below 60 mg/l, Ammonia Nitrogen was undetectable in the effluent. The modified activated sludge process was found to be resistant to quantitative shock loading. It could be operated with a wide range of organic loadings from 0.9 to 3.1 mg COD/mg MLSS/day successfully. Even when it was operated at an organic loading of 5 mg COD/mg MLSS/day, a COD removal efficiency of 88% was obtained. The modified activated sludge process was superior comparing to different activated sludge processes studied by TSUI (1974) to treat the same kind of wastewater, The modified activated sludge process was eliminate bulking sludge, rising sludge, and sludge disposal problem. It does save a lot of nitrogen in the treatment of nitrogen-deficient waste waters.
Year1975
TypeThesis
SchoolStudent Research Before 1980
DepartmentOther Field of Studies (No Department)
Academic Program/FoSThesis (Year <=1979)
Chairperson(s)Yang, Yi Ping
Examination Committee(s)Pescod, M.B. ;Nguyen Cong Thanh
Scholarship Donor(s)Shell International Company
DegreeThesis (M. Eng.) - Asian Institute of Technology, 1975


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