生物聚沉氧化法快速处理奶牛场粪污废水的研究

A novel approach of dairy cattle slurry treatment by using biological coagulation removal of suspended solids followed by sequencing batch reactor process

[目的]生物聚沉氧化法是一种利用产絮凝剂的微生物对粪污进行处理,然后固液分离去除粪污中的悬浮固体(SS),继而采用常规的生化方法处理固液分离后清澈废水的方法。[方法]针对奶牛场固液分离所产生的"浓浆水"高含固率、高化学需氧量(COD)和高氨氮的特点,通过摇瓶培养试验、中试试验和序批式活性污泥法(SBR)处理试验,研究不同处理下生物聚沉氧化法对奶牛场粪污除渣和生物净化的效果。[结果]奶牛场粪污经生物聚沉处理后脱水效果得到了提高,比阻大幅度降低:粪污比阻从初始9.8×1013m·kg^(-1)下降到24 h时的0.73×10^(12)m·kg^(-1),降低了99.26%。在最佳处理条件下进行多批次中试研究,并采用隔膜厢式压滤机进行压滤脱水。经生物聚沉反应后,压滤机粪污处理量大幅度提高,其压滤粪饼含水率在60.90%左右,比原始稀释粪污压滤粪饼体积减少了近87.09%,达到了粪污明显减量化的目的,且粪饼干基有机质含量几乎不损失,有利于后续资源化利用。此外,压滤出水中COD、SS、总氮(TN)、氨氮(NH_3-N)和总磷(TP)含量分别从原始粪污的91 470、69 500、5 125、957和129 mg·L^(-1)一步降低到1 776、<10、262、236和1.89 mg·L^(-1),去除率分别达到98.06%、99.98%、94.89%、75.34%和98.53%。压滤水再经SBR工艺处理,出水水质基本达到国家标准《畜禽养殖业污染物排放标准:GB 18596—2001》,出水可用于奶牛场自身牛舍冲洗用水和绿化用水等,生物聚沉氧化法系统处理时间不足48 h,比传统工艺时间大幅缩短。[结论]采用生物聚沉氧化法处理处置奶牛场粪污具有较高的潜在应用价值。

[ Objectives ] Biological coagulation and oxidation of dairy cattle slurry was a process by which suspended solid（SS） in the slurry was removed by using flocculant-producing microorganisms followed by diaphragm pressure filter to separate solid and liquid, then the filtrate was biologically purified by sequencing batch reactor（SBR） model. [ Methods] Dairy cattle slurry is characterized by high concentration of suspended solid, chemical oxygen demand（ COD）, and ammonia nitrogen. In this study, dewaterability of dairy cattle slurry facilitated by biological coagulation process was investigated through batch flask experiments, pilot scale testes and SBR experiments. [Results]Results showed that dewaterahifity of dairy cattle slurry was improved after biological coagulation,exhibiting a significant reduction for specific resistance to fihration（SRF） of the slurry. SRF value decreased from initial 9.8×10^13m·kg^-1 to final 0.73×10^13m·kg^-1 after 24 hours of biological coagulation reaction with the reduction of 99.26% compared to the control. The bio-coagulated slurry was dewatered by chamber filter press to produce a clear filtrate without SS and a semi-drying cake with the moisture content of about 60.90%. As a result, sludge volume was reduced by 87.09% compared with the control. Moreover, the semi-drying dewatered slurry cake contained similar levels of organic matter to original dairy cattle slurry on dry basis, indicating that it was conducive to its consequent reutilization. At the same time, the concentration of COD, SS, total nitrogen （TN）, NH3-N, and total phosphate（TP）in the filtrate decreased to 1 776,〈10,262,236 and 1.89 mg·L-1 from initial 91 470,69 500,5 125,957 and 129 mg. L-l with removal efficiencies of 98.06% ,99.98% ,94.89% ,75.34% and 99.85%, respectively. Furthermore, the filtrate was purified by SBR model, the effluent quality almost met the Discharge Standard of Pollutants for Livestock and Poultry Breeding： GB 18596-2001, implying that the effluent could be acted as reclaimed water. The overall disposal time was less than 48 hours which was much shorter than the traditional process. [ Conclusions] Biological coagulation and oxidation process has better potential for the treatment and disposal of dairy cattle slurry.