A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 2000

Factory A is a concentrated latex processing industry with the average field latex production of 56 tons/day and consumes water of average 0.5 m3/ton field latex. As the results of high organic of rubber composition and chemical use in processing, pollutant load in wastewater is very high. 658.46 kg BOD/d, 1108.75 kg COD/d, 86.19 kg N/d, 5.36 kg P /d, and 44.60 kg SS/d were generated from concentrated latex and skim rubber block processing. This high pollutant loading entered the existing effluent treatment system which comprised of anaerobic ponds, aerobic pond, and facultative pond in series. The efficiency of the system was 99.78% BOD and 98.58% COD removal. However, anaerobic condition generated odor problem in anaerobic pond. That was unacceptable by community and leaded to protest. Ammonia use in processing also attributed to atmospheric pollution in workplace. Modification was urgently needed, and it was done by operating only aerobicfacultative at the existing system and providing some modification. After operating for a while, in one hand, odor problem can be attenuated into the satisfied level, in the other hand, the quality of effluent was receded. The effluent from modified system contained BOD 43 mg/L and COD 203 mg/L that was not satisfied the standard. The efficiency of overall system decreased to 98.27 and 96.94% removal of BOD and COD. In order to meet the highest reduction in all problems, waste minimization was introduced as the most effective solution. Changing behavior in housekeeping can reduce water usage. Secondary preservative should be applied to reduce ammonia concentration in latex that can couple with reduction of ammonia vapor in atmosphere.