Study On Two-Phase Anaerobic Technology For High Concentration Organic Wastewater Treatment

A new technique of treating wastewater from slaughtering industry based on two-phase anaerobic-aerobic theory is presented in this paper, which is abbreviated to TPAD-O system. The system's capability of treating wastewater with high concentration and tinting strength, treatment efficiency, change in microorganism species and treatment characteristics have been studied.The experiment art is phased through controlling volumetric loading in combination with chemical method; i.e. according to the determined volumetric loading parameters and chemical method, a certain amount of CCl4 is added to limit the acid-producing reaction to acid-producing phase so that methane-producing bacteria can keep highly active.The fundamental conditions of rapidly starting the two-phase anaerobic reactor are studied. The experiment results show that when the value of pH is within 4.5～6.0, temperature 27℃±2℃ and organic loading 1kg/m3.d～10kg/m3.d, starting reactor is relatively easy.The experiment results of TPAD-O applied to treatment of slaughtering wastewater of high organic concentration with its loading at 7～19kgCOD/m3·d show that the removal efficiency of TPAD-O is generally staying at 90% and the concentration of COD contained in treated wastewater is below 600mg/l; so TPAD-O boasts an conspicuous high removal efficiency and stable performance compared with traditional anaerobic techniques.The optimum working conditions of acid-producing phase with two-phase anaerobic-aerobic technique is as such: temperature, 15～35℃; pH,4.5～6.5; organic loading, 4～20kgCOD/(m3·d). Generally speaking, the efficiency of removing COD of acid-producing reactor is kept within 25～35％.Study results show that the degradation of organic matters in acid-producing reactor is just a pre-treatment to some degree, organic matters are not completely degraded in the course of acid production, but their morphological properties are altered, matters made of big molecules are broken down into ones composed of small molecules, which, previously defying biochemical treatment, can be biochemically degraded. As a result, some organic materials, not easily detected with BOD5 because of their existing form of COD, can be decomposed into some matters subject to easier detection with BOD5 in the process of acidification, which will notably increase the ratio of BOD5 to COD.This technique was used to have treated wastewater discharged from a slaughtering processing factory with a good effect.