Treatment of domestic sewage with two stage system using humicola sp.

Abstract

$\underline{Humicola}$ sp. was known to have several good characteristics in wastewater treatment such as rapid growth rate, good settlability, broad spectrum of utiliazble substrate, and broad pH range to grow. An activated sludge process in conjunction with an Humicola sp. cultivation reactor was tried to treat rapidly with high feed rate artificial sewage and rice-washed water as main domestic sewage which are high TOC, nitrogen and phosphorus concentration using mean cell residence time (MCRT) as a control parameter. Dilution rate of the first reactor with Humicola sp. as 0.18/hour and of the second reactor with activated sludge 1.13/hours which are three or four times higher than that of conventional system. With artificial sewage MCRT``s of the system to achieve maximum treatment of TOC, nitrogen and phosphorus was found to be 8 days in the first stage and 10 days in the second stage and treatment efficiency were 80%, 69% and 82%, respectively. With rice-washed water at the above MCRT``s of the system TOC, nitrogen and phosphorus removal efficiency were 90%, 65%, and 70%. Settling characteristic was relatively acceptable above 6.5 days of MCRT of each reactor and was good above 10 days of MCRT with artificial sewage. In treatment of rice-washed water settlability of each reactor was very good any bulking phenomenon was not appeared during experiment. In conclusion, high starcheous wastewater may be treated by this system further efficiently without any undesirable phemonena.