猪场废水厌氧消化过程中的除磷效果

采用序批式半连续厌氧消化试验方法,研究猪场废水厌氧消化过程中磷的去除情况。结果表明,水力停留时间（HRT）为1、3、6和9 d的厌氧反应器平均除磷率分别为65.0%、81.1%、82.7%和83.0%,而COD平均去除率分别为54.5%、82.3%、87.0%和85.9%。厌氧反应器除磷能力随沼气产量的增加而增加,说明厌氧反应器中磷的去除与产甲烷过程密切相关。对厌氧消化前后的污泥进行浸提后发现,厌氧消化过程中,化学反应生成磷酸盐沉淀的除磷作用十分显著,污泥中正磷酸盐,与铁结合的磷化合物（Fe-RP）,还原可溶性磷,与钙、镁离子结合的磷化合物（Ca-RP、Mg-RP）以及无机或有机聚合磷增加量分别为0.027 8～0.101 5、0.013 5～0.081 0、0.2165～0.430 5、23.4～54.8和7.2～21.5 mg.g-1;且总体而言,HRT越长,污泥中与不同金属结合的磷增加量就越大。从HRT、磷和有机物的去除效果以及沼气产气速率3个方面综合考虑,猪场废水厌氧消化反应器的HRT控制在3 d为宜。

Phosphorus Removal From Swine Wastewater Through Anaerobic Digestion

A sequencing batch semi-continuous anaerobic digestion experiment was carried out to study effect of anaerobic digestion on phosphorus removal from swine wastewater.Results show that the phosphorus removal rate of an anaerobic digester with hydraulic retention time（HRT） being 1,3,6 and 9 d was 65.0%,81.1%,82.7%,and 83.0%,respectively,and its COD removal rate was 54.5%,82.3%,87.0% and 85.9%,respectively.The phosphorus removing capacity of the digester increased with the increasing of its biogas yield,which suggests that phosphorus removal is closely related to methane production in the digester.Extractions of the sludge before and after anaerobic digestion revealed that precipitation of phosphate formed through chemical reaction during the process of anaerobic digestion played a critical role in removal of phosphorus.Orthophosphate,iron-bound P,reductant soluble P,calcium-bound P and magnesium-bound P,inorganic or organic polymer phosphorus increased by 0.027 8-0.101 5,0.013 5-0.081 0,0.216 5-0.430 5,23.4-54.8 and 7.2-21.5 mg·g-1,respectively.Generally speaking,the longer the HRT,the greater the increment of phosphorus bound with various metals in the sludge.Taking into comprehensive consideration of HRT,efficiency of phosphorus and organic compounds removal,and biogas production rate,it is advisable to retain swine wastewater in the digester for 3 days.