Research On Flow Pattern Of Different Inflow Ways Of Sequencing Batch Rcactor

SBR process is a kind of sewage biological treatment technique which is popular studiedrecently both domestic and foreign. The process has the advantages like small footprint,flexible operation mode and so on. However, the recent study on SBR process mainlyconcentrate on process deformation and nitrogen and phosphorus removal without payattention to water flow regime study in SBR pool. By doing experiments which differentwater feeding pattern influence the water flow regime in SBR pool to find out the optimumwater feeding pattern.This article bases on tracer experiment and we first look for the optimum tracer. Thenclear water experiment is conducted, the clear water experiment includes3parts: how inflowinfluence effluent under different water feeding layouts; how inflow influence effluent underdifferent rate of inflow; how inflow influence effluent under different temperature differencebetween inflow and inside of the SBR pool. At the same time, we conduct flow regimesimulation of the SBR under different water feeding pattern using Fluent software. Thedetailed research results are as follows:(1) The inlet layout of SBR will produce different effects on the outflow. There are fourdifferent inlet layouts, such as inlet located away from the fixed weir is A water inflow way,the position of the inlet in the middle of the SBR pool of central is B water inflow way, theposition of the inlet in the middle of the SBR pool of low is C water inflow way, and theposition of the intake is close to the fixed weir of the pool of central is D water inflow way.By doing experiments, inlet layout located away from the fixed weir is a best water inflowway.(2) Based on above experiments, the water feeding pattern adopts inlet layout located farfrom fixed weir. The rate of inflow which has the smallest influence on effluent is1.1m3/hunder different rate of inflow for0.5m3/h，0.7m3/h，0.9m3/h，1.0m3/h，1.1m3/h，1.3m3/h，1.5m3/h and1.7m3/h.(3) Downward gravity flow may occur because of the density contrast resulted frominflow temperature being lower than Inside of the SBR pool. Upward gravity flow may occurwhen there exits density contrast resulted from inflow temperature being higher than inside ofthe SBR pool。The influence of inflow upon effluent will be small when downward gravityflow resulted from inflow temperature being lower than that inside of the SBR pool occurswhen analyzing from synchronous inflow and effluent SBR process structure.(4)Simulating from Fluent software we get that though in different rate of inflow, Theflow field is nearly the same when water flow regime get stable and there will always formbackflow whatever the flow rate is. What’s more, effluent moves along the direction of poolwall and speed gets smaller as time passes by. There will be a dead zone at the corner close tofixed weir underneath in the middle of the pool.(5) Temperature influences physiological activity of activated sludge when cultivatingactivated sludge. The activated sludge gets mature in the condition of indoor averagetemperature being about14.8℃and after20days of cultivation and the COD removal ratecan reach more than86%.(6) Basing on the COD measurement of24hours a day, the COD value per hour from municipal sewage pipeline get biggest during16:0019：00and smallest during0:005：00.