EFFECT OF AMMONIA AND COD TO SULFATE RATIO ONTREATMENT PERFORMANCE OF CONCENTRATED LATEXPROCESSING WASTEWATERSIRIUMA JAWJIT AND WARIT JAWJIT
The objective of this study is to investigate the effects of ammonia nitrogen (NH3-N) and COD to sulfate ratio on the treatment performance of concentrated latex processing wastewater (CLPW). In a batch experiment, the CLPW influent COD, % granular sludge and pH were controlled at about1,200 mg/l, 10% and 7, respectively. The influent NH3-N concentrations varied at 100, 500, 1000 and3000 mg/l, whereas COD/sulfate ratio varied at 0.3, 0.6, 1 and 1.3. Treatment performance was determined by methane generation rate and COD removal efficiency at different NH3-N and COD to sulfate ratio. The NH3-N concentration at 100 and 500 mg/l (which were presented in the real CLPW), did not result in inhibition on methane producing bacteria (MPB), since methane generation was detected. Inhibition on MPB was observed at 1,000 mg/l NH3-N. Strong inhibition occurred at 3,000 mg/l NH3-N, since % COD removal was relatively reduced to 7.98 % and nomethane generation. The COD/sulfate ratio at lower than 0.6 resulted in inhibition of MPB, but in the real CLPW the ratio is normally higher than 0.6. Ammonia concentration higher than 1000 mg/l and COD to Sulfate at lower than 0.6 resulted in inhibition of methane producing bacteria in the treatment of CLPW.