Effects Uncoupler (TCS) For Sludge Reduction And Water Quality

Activated sludge treatment is the biological treatment technology extensively applied in municipal wastewater treatment plant in the worldwide. However, a large quantity of excess sludge is generated as a byproduct, which is the main drawback of activated sludge treatment. Since there are many different organic pollutants, metals and pathogenic bacteria in excess sludge, it causes new environmental pollution without proper disposal. Excess sludge treatment and final disposal require highly capital and operating cost and the process is not easy to proceed. The best solution is to reduce excess sludge production from activated sludge treatment process through advanced technology.Adding metabolic uncoupler to activated sludge to modify metabolism of microorganism in sludge. Make anabolism and catabolism uncouple and energy reveal, result in biomass growth decrease. Then excess sludge generation is also decrease.This study focused on3,3’,4’,5-tetrachlorosalicylanilide (TCS) which is environmental friendly metabolic uncoupler, added into activated sludge to testify its influence on sludge production. The changes on oxygen requirement, settling property and COD removal were also studied. The results show:when the concentration of TCS was10mg/l, initial sludge is1000mg/l, sludge yield could be reduced35.0%; however, when the concentration of TCS was kept at10mg/l, initial sludge decrease at800mg/l, sludge yield reducing radio could be reach as high as78.0%. In other words, the radio of metabolic uncoupler concentration to initial sludge concentration is inversely proportional to sludge production. At the first test condition, COD removal rate was not effected; at the second test condition, COD removal rate was negative effected lightly.Adding metabolic uncoupler TCS could also extremely increase specific oxygen uptake rate (SOUR), from143.53mgO2/g VSS h in control test to233.82mgO2/g VSS h in dosage test. It means TCS could make microorganism in sludge require much more oxygen, and could activate microorganism at some extent. As a result, sludge generation was reduced.Metabolic uncoupler technology will reach a better reduced sludge production if combined with other technologies, such as heavy metal and OSA technologes. Moreover, sludge settlement characteristics will be improved through metabolic uncoupler combined with OSA technology.Although metabolic uncoupler has effective impact on reducing sludge production, it requires more oxygen, and has negative impact on nutrient removal, settling property etc. Besides, microorganism may resistant to metabolic uncoupler and the biodegradability, the impact on nature environment is little known right now.