A thesis submitted in partial fulfillment of the requirement for the degree of Master of science

Thesis (M.Sc.) - Asian Institute of Technology, 1992

A medium scale mun g bean starch factory was taken in this s tudy in order to assess t h e pollution caused by various streams in a starch/noodle factory and pr ovide basic information for wast e water management in s tarch/noodle factories. To compare the characteristics of waste water from different facto ries, other two s mall sca le noodle factories were a lso taken into consideration . The medium scale factory u ses mun g bean as raw material and produces approximately 18 ton starch a nd 11 ton protein out of about 50 ton mun g b ean ea c h day with 6-10 ton of raw material getting into waste stream. The results of t his research s how that t h e water con s umption for processing one ton mun g bean in the factory is 16-25 m3 hig he r tha n theoretically required, t ha t everyday 30 - 140 kg out of 3-6 ton starch used for v ermicelli production is wasted, which also goes into waste water, a nd that the characteristics of total waste water from t his factory are as s uch: COD = 3000-5050 mg/l, SS = 1100-1600 mg/l, TKN = 100-250 mg/l and TP = 30-50 mg/l. The same kinds of infor mation about t h e other two small scale factories were also given in t he study and the comparison with the medium o ne have been made. Based on t he research, methods have been proposed for minimizin g the wast e water produced by t h ese factories so as to r edu ce t h e pollution. One of t he alternatives is to use wate r in a con trolled way b y ma rkin g optimum flow rates on t he tab valves, in whic h water con s umption can be b roug ht down from 16-25 m3 to 12 m3 for processin g on e ton mung bean.