上海地区畜禽场大、中型沼气工程沼渣液后处理技术调查研究

An Investigation on the Post-treatment of Biogas Residue and Water on Medium- and Large-scale Animal Farm in Shanghai District

提高沼渣液分离率的工程工艺技术在减轻后处理的工作量上起重要作用;沼渣液的后处理工程技术与发酵原料有极密切关系。猪鸡食谷类,谷物的比重>1,在水中发生沉淀,可采取沉降分离、离心分离法;而牛主食草料,因草的比重<1比水轻,在水中产生悬浮与上浮现象,故对牛粪沼渣液的分离只能采取筛滤分离方法。其后,对分离的猪鸡牛粪沼液均可采取氧化沟塘;农田漫流由土壤、生物、藻类、水生植物逐级降解;在有条件的地方可采用种植蔬菜等旱作物,应用沼液地下渗灌施肥兼污水处理,经土壤吸附利用后可做到达标排放,有效地防治了水质污染。

To raise the rate of separation of the water from biogas residues is very important in reducing the amount work which will be done in post-treatment of biogas engineering.The separation technology is close related to the kind of raw material to be used in producing the biogas. For instance, if the raw material is the dung of pig or chicken,the water can be separated from the residue by sedimentation or centrifugal force. The reason is that the feed for pig and chicken contains a large proportion of grains. The specific gravity of grain is larger than one,so the solid residue will be precipitated to the bottom and the water will be floated on the top. While the raw material is cow's dung,the only way to draw the water from residues is with sieve. As the cow's main feed is grasses, which makes the specific gravity of its dung less than one,so the residue and water mixture is in a colloidal state.Then all the water from biogas residues may be drained into the trench or the pit to let the water to be oxidized by the air in order to make the water under the aerobic fermentation. The last step is to drain the water into the field to let the soil,microorganisms,algae,aquatic plants to decompose all the organic matters within the biogas water to be purified step by step to form a noncontaminated liquid fertilizer. If the condition is permitted, the best way is to use the underground permeated irrigation technology for vegetables or other dry crops to purify the biogas water by the adhesion function of soil particles.