Study On The Efficiency Of ASBR-SBR Process For The Dairy Manure Wastewater Treatment At Ambient Temperature

Now the human being is facing the pressure of development and environment. The sharpincreases of energy consumption, the increasingly extrude of conflict of supply and need, theaggravating of polluting of environment, has been the biggest restrict of the China's economicsustained development. It is the direct threat of National Economic Security. So it is a veryimportant subject to develop the new energy and its transformation in the state economicconstruction. Anaerobic fermentation of animal waste as a reliable energy resource is a promisingtechnology to deal with these problems. Anaerobic sequencing batch reactors (ASBR) can getshorter hydraulic retention time (HRT) which means smaller reactor needed and better economiceffect, and keep longer solid retention time (SRT). As other anaerobic treatment technology, ASBRcan not remove nitrogen, so sequencing batch reactor (SBR) is added. In this thesis the starting ofASBR reactor and the factor that affect it in low temperature are studied. Finally, the treatmenteffect and the nitrogen removing of ASBR-SBR system were experimented. The major contentsand results included the following aspects:1. The ASBR reactor can be started successfully at 25℃in a relatively short time. When thereactor's temperature was decreased to the laboratory ambient time, turn off the heating equipment.The temperature in anaerobic digester changed with the ambient temperature. The reactor showedgood buffering capacity during the experiment, and functioned well. When the temperaturechanged within 17℃～20℃, the change of removal of COD is not significant. The effect oftemperature changing on the treatment efficiency of ASBR can be ignored. We can conclude thatthe ASBR could achieve satisfactory result in the condition that the temperature is not maintainingconstant, and with some economic benefits.2. Study on the different organic loading rate (OLR) with ASBR at ambient temperature. Theresults indicate that optimal effects are achieved when the OLR is 5 gVS/(L·d), the volume gasproductivity is 1.09 L/(L·d), VS gas productivity is 0.22L/gVS, the removal of COD and SCOD are35.4% and 50.3%, the removal of TS and VS are. 15.8% and 19.1%, the content of CH₄ in biogas is77.76%.3. Under the condition of the experiment, the effect of treatment of dairy wastewater with ASBR at different period was studied, the period is 12 hours, 24 hours. We can see from the biogassproduction, the period of 12 hours is superior to the 24 hours on biogass yield, the volume gasproductivity, and VS gas productivity. If considered the removal rate only, the period of 24 hours isslightly higher than the 12 hours. But if take account of economic benefits and treatment results, wewill still choose the period of 12 hours.4. Study on the three different agitating time with ASBR at the OLR of 5 gVS/(L·d), 3 min/h,5 min/h and 2.5 min/30min. Because of the low temperature, the viscosity of the fluid in the ASBRis high, the longtime gas agitation is advantaged to the contact of ground substance with the fluid.The result indicated that when intermittent agitation is 5 min/h, the removal rate of COD is higher.5. Finally, the organic removal rate and nitrogen removement of ASBR-SBR system werestudied. The OLR of ASBR is 5 gVS/(L·d), the period is 12 hours and the ASBR and SBR areexposed to ambient environment. The results show that ASBR is quite suit to the removal oforganic, and SBR can achieve obvious effect of biological denitrification. The two combinedcrafts can remedy their disadvantages. ASBR-SBR technics can get high removal rate ofcontamination, the removal of COD is 50%. The removal rate of NH₃-N achieves 92.8%.