江苏省大型沼气工程沼液理化特性分析

Physical and chemical characteristics of anaerobically digested slurry from large-scale biogas project in Jiangsu Province

集约化畜禽养殖场沼气工程是一项提供清洁能源、减轻环境污染、潜力巨大的生物质能源工程。该研究采集了江苏省21个规模化养猪场和奶牛场内大型沼气工程的沼液样本,进行了氮磷钾等理化特性分析。结果表明,由厌氧反应罐排出的沼液呈中性至微碱性,还原能力较强。猪场和奶牛场沼液中总氮分别集中在400～900mg/L和200～400mg/L范围内,其中铵态氮占总氮量的70%以上;总磷分别集中在30～100mg/L和300mg/L以上,可溶性磷含量变异较大;总钾分别集中在100～500mg/L和500mg/L以上。沼气工程运行时间对沼液理化性状影响显著,运行时间越长系统稳定性越好。氧化塘对沼液中颗粒物、氮素和磷素有显著的削减作用,多级氧化塘处理效果更明显。

Biogas plant in the intensive livestock and poultry farm is a large potential biomass energy project,which could provide clean energy and reduce the stress on environment. However,studies about nutrient management of biogas by-product （i.e. anaerobically digested slurry （DS）） were few. Characteristics and nitrogen （N）,phosphorus （P） and potassium （K） contents in DS from 21 large-scale biogas projects were investigated in intensive piggery and dairy farms in Jiangsu Province. The results showed that the investigated DS from digested reactors was reductive and pH values were neutral and weak alkaline. Total N of DS in piggery farms and dairy farms were concentrated on 400 to 900 mg/L and 200 to 400 mg/L,respectively,and 30 to 100 mg/L and 300 mg/L for total P,100 to 500 mg/L and 500 mg/L for total K. More than 70% of N was ammonium N. Total and dissolved P varied greatly among the investigated sites. Anaerobic reactor became more steady with running time,which significantly influenced on the physical and chemical properties and nutrient characteristics of DS. Oxidation pond （OP） could significantly cripple the suspended solid,N and P in DS. Compared with the primary OP,multi-stage of OP had better crippling effect.