Study On Livestock Wastewater Treatment In Sequencing Batch Biofilm Reactor

As livestock and poultry breeding developing rapidly on a large scale, the pollution of the livestock and poultry breeding wastewater becomes the most important pollutant source besides industrial wastes and domestic sewage. Nowadays the confliction between livestock and poultry breeding and invironmental pollution became marked, which is incompatible with the sustainable development of the former. The livestock and poultry breeding wastewater consists of excreta, scraps and feathers, as well as the cleaning water from the livestock production factories, having a high concentration of organisms, large proportion of ammonia and foul smell. This paper is probing the feasibility of treating the livestock wastewater by an independently developed type of sequencing batch biofilm reactor (SBBR). Focusing on the effects of organisms and nitrogen removal at the startup step in this new type of SBBR. The mechanism of the nitrogen-removal at the startup step with different modes was analyzed. And the influences of modification on the mechanism and the removal effect on the nitrogen were investigated. During this experiment, the formation of biofilm and the change of the aquatic organisms were studied. The stability of this new type of SBBR and the effects on treating livestock and poultry breeding wastewater when operating experiment were also explored. The appearance of sludge bulking in this new type of SBBR was also investigated. Results are summarized as follows:(1) In the continuous aeration startup mode, the average influent concentration of COD and total nitrogen were 2200mg/L and 130mg/L respectively. COD was 177.5mg/L in the effluent. The removal rates of COD and total nitrogen were 91.74% and 80.24% respectively. Showed this new type of SBBR has an excellent ability to buffer shock loading.(2) In the start-up experiment with the expectation mode, the removal rates of COD and total nitrogen were 91.15% and 73.4% respectively. By improving the expectation mode, the reactor kept a high removal rate of COD and increased the removal effect of nitrogen. The removal rates of COD and total nitrogen reached 91.65% and 81.44% respectively. By investigating the mechanism of the nitrogen removal in the different modes, results showed that there were traditional nitrification and denitrification, shortcut nitrification and denitrification and also simultaneous nitrification denitrification. And there were even better removal effect of total nitrogen in the improved mode.(3) By operating this experiment, this new type of SBBR was steady in performence. With the improved mode, this new type of SBBR was able to remove organisms and nitrogen, and the efflunt was clean and without malodor. These results showed that this new type of SBBR could be used in treating the livestock and poultry breeding wastewater.(4) By analyzing the biofacies in the reactor, results showed that the biofilm grew up gradually during the start-up experiment process. Ecosystem in this reactor was composed of bacteria and various aquatic organisms. They helped to keep the steability of the ecosystem in this new type of SBBR. And this stabilization was good for improving the removal effect.(5) By investigating the sludge bulking in this new type of SBBR, results showed that the low temperature was the most important factor resulting in sludge bulking in this new type of SBBR. This paper offered some methods to estimate and prevent the sludge bulking, It also provided some methods to recover the system destroyed by the sludge bulking.These results can provide some scientific guidelines for the future study on the livestock and poultry breeding wastewater treatment by using this new type of SBBR.