Effect of solids retention time and temperature on waste activated sludge hydrolysis and short-chain fatty acids accumulation under alkaline conditions in continuous-flow reactors.
The effects of solids retention time (SRT) and temperature on waste activated sludge (WAS) hydrolysis and short-chain fatty acids (SCFAs) accumulation were investigated in a series of continuous-flow reactors at pH 10. The experimental results showed that the increase of either SRT or temperature benefited the hydrolysis of WAS and the production of SCFAs. The changes in SRT gave also impact on the percentage of acetic and propionic acids in the fermentative SCFAs, but little influence on that of the slightly long-chain SCFAs, such as n-butyric, iso-butyric, n-valeric and iso-valeric acids. Compared with the control (pH unadjusted) experiment, at SRT of 12d and temperature of 20 degrees C the concentration of SCFAs produced at pH 10 increased from 261.2 to 933.5mg COD/L, and the propionic acid percentage improved from 11.7 to 16.0%. It can be concluded from this investigation that the efficient continuous production of SCFAs at pH 10 is feasible.
Feng
Leiyu
L
State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, China.
Wang
Hua
H
Chen
Yinguang
Y
Wang
Qin
Q
D000468:Alkalies / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007220:Industrial Waste / Q000517:prevention & control*; D010758:Phosphorus / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D013696:Temperature
D000468:Alkalies; D005232:Fatty Acids, Volatile; D007220:Industrial Waste; D000644:Quaternary Ammonium Compounds; D012722:Sewage; D010758:Phosphorus