生物快滤池深度处理污水厂二级出水性能研究

采用生物快滤池对城市污水厂二级出水进行了深度处理试验,并对滤池的运行参数进行了探讨。结果表明,生物快滤池对进水水质有良好适应性,除卫生学指标外,其出水绝大部分时间可满足《城市污水再生利用城市杂用水水质标准》(GB/T18920-2002)。生物快滤池法宜采用下列参数:逐渐增加进水流量的自然启动:2～3mm的陶粒滤料;滤层厚度2 000 mm;上向流过滤:滤速3．2～6．4m／h;过滤周期24～120h,平均为72 h;气水比控制在(1—2):1之间;气水联合反冲洗。     

利用反应热处理制备纳米晶WC-10Co复合粉末

对反应热处理技术(即高能球磨+热处理)合成纳米晶WC 10Co复合粉末的工艺进行了研究.DTA和X ray衍射分析结果表明:以W,Co粉和碳黑为原料的混合物经过一定的活化处理后,碳化钨可在572℃左右形成;当温度为800～1100℃,热处理时间为15～35min时,合成的纳米碳化钨晶粒尺寸为9～42nm.反应热处理技术是合成纳米晶WC Co复合粉末的一种可行的方法.     

Landfill leachate treatment by MBR： Performance and molecular weight distribution of organic contaminant

A membrane bioreactor (MBR) with an air-lift bioreactor and gravity flow is applied to treating landfill leachate. More than 99% of BOD5 (biochemical oxygen demand for five days) removal effi-ciency is achieved with less than 35 mg/L of BOD_5 in the effluent at less than 1.71 kg BOD5/m~3·d of BOD_5 loading rate. When DO (dissolved oxygen) is maintained at the range of 2.3―2.8 mg/L and the loading rate of NH_4~ -N (ammonium nitrogen) is kept at 0.16― 0.24 kg NH_4~ -N/m~3·d, the NH_4~ -N in the effluent is less than 15 mg/L. However, compared with high removal rates of BOD_5 and NH_4~ -N, the removal effi-ciency of soluble chemical oxygen demand (SCOD) varies between 70% and 96%. The investigation of molecular weight (MW) distribution has been carried out by the gel permeation chromatography (GPC) so as to understand the fate of organic matters in the MBR treating of landfill leachate. Results indicate that organic matters of the landfill leachate are composed of a high MW fraction (MW of the peak, MWp = 11480―13182 Da) and a low MW fraction (MWp = 158―275 Da). The high MW fraction is not biode-gradable, but can be decreased with microfiltration membrane. The most of the low MW fraction is bio-degradable, but the residue of the low MW fraction is able to permeate through the membrane, thus re-sulting in high SCOD in the effluent of the MBR.