沼气工程沼液高值的利用研究

Research of the High Value Use of Biogas Slurry from Biogas Projects

为了解决沼气工程中沼液产量大、处理成本高、储存运输困难和营养物质含量偏低等问题,提出采用高耐污反渗透技术对沼液进行浓缩,以实现沼液高值利用。实验分析了沼液膜浓缩技术的可行性,并对浓缩后水质做了简单介绍;同时通过浓缩液种植大白菜实验,对浓缩液作为追肥对大白菜的产量、品质的影响做了分析。结果表明:通过对膜通量及其影响因素的分析,采用反渗透技术浓缩沼液可行,最佳压力运行范围为4～5.5MPa,进水电导率和温度符合反渗透膜技术的要求,沼液通过膜浓缩后清水能够回用于调浆,浓缩液中营养元素更加集中可以用于农业种植,沼液浓缩液中氮素能满足大白菜生长要求,最佳施入量为1100kg/hm2氮,在此条件下既能维持大白菜的高产,又能协调周边环境效应,利用沼液种植能提高大白菜品质,硝酸盐含量能较好的维持在600mg/kg以下。

In order to solve problems in biogas slurry of biogas project, such as its large amount, difficulties in disposal, storage, transport and low nutrients, high resistant contaminated reverse osmosis used to concentrate biogas slurry were put forward accordingly so as to achieve the high-value use of the biogas slurry. The feasibility of concentrating biogas slurry technology by membrane was analyzed, then the water quality of biogas slurry concentrated by membrane was introduced in brief. At the same time, by planting cabbage test used concentrated slurry as fertilizer, yield and quality of cabbage was studied. The results showed that the reverse osmosis technology concentrating the biogas slurry was feasible according to the analysis of the membrane flux and its influencing factors, the best operating pressure range was 4-5.5 MPa, reverse osmosis technology requirements were met by input water conductivity and temperature of the biogas slurry. The permeate water of RO system could met the standard of slurry mixing. Besides, the concentrated water could be widely used for agriculture due to its richer nutriments. Concentrating sully could met the Chinese cabbage＇s demand of N nutriment, and the best fertilized concentrating biogas slurry whose N＇ s content was 1100 kg/hm^2, at this case it not only could harmonized the high yield of cabbage of the season but also the environmental effect, moreover, using biogas slurry planting could improved the quality of cabbage, its content of nitrate of cabbage could be controlled below 600 mg/kg.