Effect of a high strength chemical industry wastewater on microbial community dynamics and mesophilic methane generation

A high strength chemical industry wastewater was assessed for its impact on anaerobic microbial com- munity dynamics and consequently mesophilic methane generation. Cumulative methane production was 251 mL/g total chemical oxygen demand removed at standard temperature and pressure at the end of 30 days experimental period with a highest recorded methane percentage of 80.6% of total biogas volume. Volatile fatty acids （VFAs） analysis revealed that acetic acid was the major intermediate VFAs produced with propionic acid accumulating over the experimental period. Quantitative analysis of microbial communities in the test and control groups with quantitative real time polymerase chain reaction highlighted that in the test group, Eubacteria （96.3%） was dominant in comparison with methanogens （3.7%）. The latter were dominated by Methanomicrobiales and Methanobacteriales while in test groups increased over the experimental period, reaching a maximum on day 30. Denaturing gradient gel electrophoresis profile was performed, targeting the 16S rRNA gene of Eubacteria and Archaea, with the DNA samples extracted at 3 different time points from the test groups. A phylogenetic tree was constructed for the sequences using the neighborhood joining method. The analysis revealed that the presence of organisms resembling Syntrophomonadaceae could have contributed to increased production of acetic and propionic acid intermediates while decrease of organisms resembling Pelotomaculum sp. could have most likely contributed to accumulation of propionic acid. This study suggested that the degradation of organic components within the high strength industrial wastewater is closely linked with the activity of certain niche microbial communities within eubacteria and methanogens.     

Nitrogen mass balance in a constructed wetland treating piggery wastewater effluent

The nitrogen changes and the nitrogen mass balance in a free water surface flow constructed wetland （CW） using the four-year monitoring data from 2008 to 2012 were estimated. The CW was composed of six cells in series that include the first settling basin （Cell 1）, aeration pond （Cell 2）, deep marsh （Cell 3）, shallow marsh （Cell 4）, deep marsh （Cell 5） and final settling basin （Cell 6）. Analysis revealed that the NH4＋-N concentration decreased because of ammonification which was then followed by nitrification. The NO4＋-N and NO4＋-N were also further reduced by means of microbial activities and plant uptake during photosynthesis. The average nitrogen concentration at the influent was 37,819 kg/year and approximately 45% of that amount exited the CW in the effluent. The denitrification amounted to 34% of the net nitrogen input, whereas the accretion of sediment was only 7%. The biomass uptake of plants was able to retain only 1% of total nitrogen load. In order to improve the nutrient removal by plant uptake, plant coverage in four cells （i.e., Cells 1, 3, 4 and 5） could be increased.     

低碳氮比条件下膜生物反应器处理高氨氮废水时稳定亚硝化过程的建立

以人工配制高氨氮低碳氮比(C/N)废水为进水,采用膜生物工艺,通过控制亚硝化池内温度为28~30℃,溶解氧浓度为0.5 mg/L,水力停留时间为12 h,pH为7.8~8.0,进水氨氮浓度为200 mg/L、CODCr为40 mg/L,在亚硝化池中成功实现了C/N为1∶5条件下废水的亚硝化。经过14 d的运行时间,污泥龄控制在100 d,在膜生物反应器(MBR反应器)中得到了稳定的亚硝酸盐氮积累。将氨氮浓度分别提高至400和800 mg/L的情况下,其亚硝化菌的耐受浓度负荷冲击能力均较强。     

铁碳微电解法预处理聚氯乙烯(PVC)离心母液废水

采用铁碳微电解法对聚氯乙烯(PVC)离心母液废水进行预处理。分别考察反应时间、铁粉投加量、Fe/C(质量比)、pH值及曝气速率对母液废水中的COD和聚乙烯醇(PVA)去除率的影响,并在此基础上通过正交实验确定了废水COD的最佳处理条件。结果表明,最佳处理条件为:反应时间为4 h、铁粉投加量为30 g/L、Fe/C为1:2、pH值为2、曝气速率为0.8 L/min。在该条件下,废水中COD、PVA和TOC的平均去除率分别为(67%±2)%、(98%±1)%和(55%±3)%,废水的BOD/COD值从0.3提高到0.5,可生化性得到了显著提高。同时,废水中的NH3-N、浊度也在很大程度上得到了去除,出水中总铁含量也很低。     

萃取结晶法回收高盐废水中的石油磺酸盐

采用萃取结晶法回收石油磺酸盐工业生产中高盐废水中的石油磺酸盐,根据溶解度筛选萃取剂,研究各萃取剂的回收效果。采用平衡法测定各溶剂对石油磺酸盐和硫酸铵的溶解度,优选乙醇、异丙醇和正丁醇为萃取剂回收石油磺酸盐并脱除硫酸铵。室温下,一定溶剂比的正丁醇对硫酸铵的结晶率远小于乙醇和异丙醇,而正丁醇回收的石油磺酸盐的纯度远大于乙醇和异丙醇,高达98%;各萃取剂对石油磺酸盐的回收率顺序:乙醇>异丙醇>正丁醇。因此,根据产品需求选择合适的萃取剂及溶剂比处理废水,从而达到脱盐和回收石油磺酸盐的双重目的。     

新型IC反应器在山梨醇废水处理中的工程应用

将布水装置优化后的新型内循环(IC)反应器应用于某山梨醇生产企业实际废水的二级厌氧生化处理,获得了较好的处理效果。调试阶段的结果表明:经过IC反应器的处理后,废水COD浓度由处理前的2 374~4 967 mg/L降至301~823 mg/L,COD去除率达81.4%~91.2%,COD容积负荷达8.1~13.7 kg/(m3·d);总体来说,当水力负荷增大时,COD容积负荷也相应增大;IC反应器的出水挥发性脂肪酸(VFA)基本控制在200 mg/L以下;厌氧出水再依次经过接触氧化池和絮凝沉淀池等配套工艺的处理后,COD降至80 mg/L以下,实现达标排放。     

氯化铵处理含钒废水的研究

钒是一种非常重要的金属元素,被广泛用于钢铁与机械制造等行业以提高金属的抗拉强度。在钒的冶炼过程中,大量的含钒废水会排放出来,其中钒的含量也远超过《钒工业污染物排放标准》(GB 26452-2011)中规定的排放标准。如果不对含钒废水加以处理,不仅仅是钒资源的浪费,排入环境的钒会对生态系统造成巨大的危害。文章针对湿法提钒工艺排放的含钒废水,提出了用铵盐处理含钒废水的处理工艺。酸性含钒废水中,钒的主要形态为六聚钒酸盐的形态存在(V6O162-),当含废水为50 mL时(含钒207.7 mg/L),5 g/L的NH4Cl用量为25 mL,待反应60 min后,铵离子和六聚钒酸盐生成六聚钒酸铵(APV)沉淀,再通过离心除去沉淀物。该方法操作简单可行,废水中钒的去除率可达96%以上,可为含钒废水的后续达标处理奠定基础。     

膜曝气生物反应器处理模拟啤酒废水的研究

以聚偏氟乙烯中空纤维膜构建无泡曝气膜生物反应器(MABR)处理模拟啤酒废水,在保持进水COD∶TN∶TP=100∶5∶1条件下,通过正交实验确定反应器的最佳运行条件,并在此条件下考察了反应器对啤酒废水中COD、氨氮和总磷的去除能力。研究表明,反应器对啤酒废水中的COD、氨氮有着良好的去除效果,系统稳定时COD与氨氮的平均去除率分别为88.6%和92.4%,此外MABR工艺具有较强的抗有机负荷冲击能力。但反应器对总磷的去除效果不够理想,平均去除率在30%左右。     

肉鸡屠宰废水综合处理技术应用研究

湖北同星农业有限公司是国家农业产业化重点龙头企业、湖北省畜牧十强企业、省高新技术企业,也是湖北省唯一一家形成肉鸡一条龙完整产业链的企业。2010年6月,同星农业有限公司启动"湖北省‘亿只鸡’产业化示范工程食品加工园"项目,该项目属于一次立项,分批次建设,故投资备案证的项目名称为"湖北省‘亿只鸡’产业化示范工程食品加工园项目"。该文研究的内容仅限于"亿只鸡"产业化示范工程一期子项目即新建年处理3 000万只肉鸡生产线项目屠宰废水综合处理。     

NF90纳滤膜除硼性能研究

压力、回收率、p H值、温度对NF90纳滤膜去除酸性模拟含硼废水中的硼有较大影响。结果表明,在压力一定时,除硼率随回收率的升高而降低,回收率一定时,除硼率随压力的升高而升高;p H在3~5时,除硼率随p H值升高而降低;温度的升高将使除硼率下降。在本实验条件下,NF90纳滤膜除硼率为20%~40%,采用NF90纳滤膜方法除硼还需进行更进一步的研究处理。