Study On Waste Water Treatment Modes Of Large-scale Pig Farms In Tianjin Area

Taking sewage treatment of large-scale pig farms in Tianjin for the study, with the combinationof questionaire survey，field investigation research method, and experimental testing analysis, thispaper analyzes current situation of sewage disposal, processing mode, management effectivenessand existing problems of large-scale pig farms whose live pig amount exceeds500heads in Tianjin,so as to provide reference and basis for sewage treatment of large-scale pig farms in Tianjin. Themain research results are as followed:First, according to the investigation into264large-scale pig farms whose live pig amountexceeds500heads, by the end of2009, among264large-scale pig farms whose live pig amountexceeds500heads, there are116ones equipped with sewage treatment facilities, whose owningrate is43.9%. Among them, facilities of93ones are under regular service, whose service ratereaches80.2%. There are246ones who have adopted technology of dry conservancy. whichoccupies93.2of the total. All of those have been above national mean level.Second, three models are included in currently processing levels of the sewage treatment inlarge-scale pig farms of Tianjin, which are precipitation, methane and the comprehensive control.There are7pig farms whose live pig amount exceeds5000heads,3of which have adoptedcomprehensive control technology in sewage treatment. The percentage is42.9%. There are15pigfarms whose live pig amount ranges from3000to5000heads.11of which have employedtechniques of methane usage in sewage treatment. The percentage is73.3%. There are94pigfarms whose live pig amount ranges from50to2999heads.57of which have employed techniquesof precipitation. The percentage is60.6%.Third, cncerning the harmlessness sewage treatment of large-scale pig farms. We have to optfor the treatment model and technology accordingly based on the breeding pattern and neighbouringecology environment.The pig farms whose live pig amount is under3000heads are suitable forprecipitation modal in sewage treatment, the pig farms whose live pig amount ranges from3000to5000heads had better employ techniques of methane usage in sewage treatment, and the pig farmswhose live pig amount exceeds5000heads are suitable for comprehensive control technology insewage treatment. However, the above-mentioned techniques need further improvement.Fourth, based on the actual situation of the large-scale pig farms in Tianjin, comprehensiveconsideration of the restricted factors, prospective and operability of administrated technology etc,with respect to area coverage, polices, technology, and administration, countermeasures andsuggestions are put forward to be aimed at sewage treatment of large-scale pig farms in Tianjin.