Removal of ammonia in the sulfide-rich wastewater using Conventional Activated Sludge process

The objective of this research is to study the performance of conventional activated
sludge in removing ammonia for the treatment of high sulfide wastewater. The variables
in this project are Sludge Retention Time (SRT) and various concentration of sulfide in
the wastewater. The scope of this project is to study the effect ofSRT on activated sludge
process in removing ammonia under different sulfide concentration. The approach
involves using waste water from Sewage Treatment Plant (STP) in front of Village 2,
University Technology of Petronas. The MLSS of primary sludge had a range of 2500
mg/L to 4500 mg/L. Five reactors was used with each SRT was varied at 10, 20, 30, 40
and 50 days. The volume of each reactor was measured as 18 L each. Waste water was
filled into every reactor and an approximate of 90 L of wastewater was fed into each
reactor everyday in a 24 hours continuous operation. The feed flow rate was set at 6.5
ml/min. 5 containers was placed under the reactors to feed the effluent, which was used
for sampling later. Each reactor had varied sludge age with different amount of sludge
was wasted everyday. Gradually, synthetic hydrogen sulfide was added in the influent
and the concentration was increased from 200 mg/L to 300 mg/L and finally 900 mg/L.
Present results showed that activated sludge system can be used to nitrify waste water
containing high amount of ammonia concentration at SRT of 10 days. In term9 of
biomass growth, SRT of 10 days shows the highest biomass growth obtained, and thus
proving to be the most optimum SRT in the removal of ammonia in sulphide-rich waste
water. More over, the increase of sulphide concentration in the system did not affect the
efficiency of each reactor since all the microorganisms had already adapted well with the
sulphide-rich environment.