Optimization Of Efficient Anaerobic Reactor For Pre-Treatment Of Rural Domestic Sewage At Normal Temperature

Compared with the aerobic process, the investment and running cost of treating rural domestic sewage is lower. With the emergence of a large number of highly efficient anaerobic reactors, anaerobic technology treating low concentration wastewater has a good future. This experiment adopts the anaerobic baffle reactor (HABR) and anaerobic biological filter (AF) to have a study of comparing, both of the reactors have the improved structure optimization. The temperature changes with the seasons, HRT is for 18 h-4 days, the COD of influent is about 350 mg/L. The research mainly focus on the contrast of the startup and normal operation of the reactors. The results show that the improved HABR can adapt to the change of the environmental conditions better. The main conclusions are briefly as follows:(1)The reactors start at the temperature of 23?, the volume load is 0.495 KgCOD/(m3·d), the HABR can successfully start after less than two months, the COD removal rate of AF reactor can achieve 78% after 63 days, the two staged series AF reactors can successfully start more than two months.(2)During the suitable temperature, we study the effect of different HRT on the COD removal rate, the COD removal rate of three anaerobic reactors both rise unsteadily when the HRT reduce from 4 days to 1 day gradually. Among the raactors, the COD removal rate of HABR is the highest which can reach 94.39%. The COD removal rate of AF reactors is higher than the HABR when the HRT reduce from 1 day to 18h, and the COD removal rate of both the reactors will decline when the HRT continue to reduce.(3)The COD removal rate of the three reactors both decline with the reduce of the temperature, but the low temperature effect of HABR is not obvious. The COD removal rate of HABR can still maintain 65% in the winter low temperature, but the COD removal rate of AF reactor and the two-stage AF filter is only 50% and 45%, so heat preservation measures should be taken in winter.(4)Both of the reactors have a certain buffering capacity, the variation of pH along the way is not obvious, the VFA concentration is less than 280mg/L, no acidification phenomenon happens across the study. The SS removal rate of HABR is over 80%, which is higher than the two reactors.(5)The remove of nitrogen and phosphorus are not very well in the three anaerobic reactors, the research adopts the "anaerobic-artificial wetland" ecological combination process, the COD concentration is lower than 50 mg/L, the ammonia nitrogen concentration generally maintains between 0.92-7.8 mg/L, the TP concentration of effluent is between 0.39-0.92 mg/L, both of the index meet the A discharge standards of the "urban sewage treatment plant pollutant discharge standard "(GB18918-2002).