Study On Pollution Controlling Strategies Of Large-scale Pig Farms

In present study, waste pollution of large-scale pig farms in Fujian province was investigated by documentation retrieving, scenario surveying and case studies, combined with quantitative and qualitative analysis, empirical and normative analysis. The waste pollution status, causes controlling measures, management effectiveness, remained problems, together with investment returns of "biogas, biogas slurry and biogas dreg" utilization were analysed. This aim to enhance the level of pollution controlling, improve the quality of environmental water in "five rivers and two streams" in Fjian province. Main results are described as follow.First, according to data released by the Pollution Survey Office of Fujian province in 2010, Pig breeding stock of Fujian province reached 13.1712 million in 2007, and 82.65% of total pigs were breeding in the scale more than 50 pigs each farm. It implied that pig farming in Fujian province had staged from the scatter into the phase of large-scale farming, and pig farming pollution had also gradually evolved into point source pollution from surface source pollution. There were three major causes of pollution, including industry planning delay, lack of effective government regulation and outstanding irregularities.Second, the surveys and data based on fifty large-scale pig farms investigation indicated that biogas engineering and its supporting technology are the main controlling measures currently, including controlling model of the agricultural circular economic model of courtyard, ecological process of energy and environmental engineering of pig farm, energy process of environmental engineering of pig farms, etc. In recent years some achievements have been made in Fujian Province. There still existed many problems, such as structural imbalance of livestock, inadequate management systems and mechanisms, weak awareness of environmental protection, low level of standard farming, low rate of biogas utilization, hardness of faeces resource utilization and so on.Third, technical and economic evaluation of biogas power generation and centralized gas supply in large-scale pig farm indicated that, it was to be profitable based on higher comparison with the full utilization and higher return rate of biogas. Compared to biogas power generation, centralized gas supply has more complex in management, lower charging standard, lower investment burden and lower economic benefits as well. But, it was the difficulty to achieve biogas power generation network for the use of biogas which was limited to meet their production requirements in large-scale pig farms, resulting in low utilization efficiency of biogas.Forth, based on the practical conditions of large-scale pig farms in Fujian Province, such as constraint factor, control technology and operational feasibility,. some constructive proposal were put forward in this paper, including pollution controlling measures and policy recommendations...