Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure: The effect of ammonia inhibition

The effect of ammonia inhibition was evaluated during the enhanced anaerobic treatment of digested effluent from a 700 m³ chicken-manure continuous stirred tank reactor (CSTR). A 12.3 L internal circulation (IC) reactor inoculated with an anaerobic granular sludge and operated at 35 ± 1 °C was employed for the investigation. With a corresponding organic loading rate of 1.5-3.5 kg-COD/m³ d over a hydraulic retention time of 1.5 d, a maximum volumetric biogas production rate of 1.2 m³/m³ d and TCOD (total COD) removal efficiency ranging from 70% to 80% was achieved. However, the continual increase in the influent TAN content led to ammonia inhibition in the methanogenesis system. The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was presented to be the key controlling factor for the anaerobic treatment of semi-digested chicken manure, and further validation through shock loading and ammonia inhibition experiments was conducted. The threshold value of the SCOD/TAN ratio was determined to be 2.4 (corresponding to a TAN of 1250 mg/L) at an influent pH of 8.5-9.     

改进型石灰混凝法去除城市污水二级出水中有机物的研究

将石灰混凝处理后的沉淀泥渣进行回流，对石灰混凝法进行改进，研究改进后的石灰混凝法对城市污水二级出水中有机物的去除效果。结果表明，活性泥渣回流有利于提高石灰混凝法对城市污水二级出水中有机物的去除。回流位置在石灰投加前、复合絮凝剂投加后，最佳回流量为新泥渣产生量的100％～200％，活性泥渣回流的最佳pH为11．0～11．5；活性泥渣中CaCO3、Mg(OH)2、Fe(OH)3等沉淀物以及有机高分子絮体均有助于提高其对有机物的去除效果，其中Mg(OH)2沉淀物起主导作用；含循环泥渣的活性污泥回流，对有机物的去除效果无明显影响。     

羟基乙叉二膦酸镀铜废液的处理及Cu~(2+)的高附加值资源化回收

采用Na BH4还原法将羟基乙叉二膦酸(HEDP)镀铜废液中的Cu~(2+)制备成纳米铜粉,并采用聚丙烯酰胺(PAM)对还原反应后的废液进行絮凝处理。研究了n(Cu~(2+))∶n(Na BH4)、还原反应温度、还原反应时间及PAM添加量对废液中剩余Cu~(2+)质量浓度的影响,并对回收的纳米铜粉进行了XRD和TEM表征。实验结果表明:当n(Cu~(2+))∶n(Na BH4)=4∶6、还原反应温度为50℃、还原反应时间为2 h时,废液中剩余Cu~(2+)质量浓度降低至1.1 mg/L,Cu~(2+)还原率达99.99%;可获得粒径为20~45 nm的近球型、高纯度、由多晶组成的纳米铜粉;当PAM添加量为10 mg/L时,废液中剩余Cu~(2+)质量浓度降至0.35 mg/L以下,达到GB 21900—2008《电镀污染物排放标准》(小于0.5 mg/L)的要求。     

EGSB出水回流对EGSB—SBR工艺处理果汁废水的影响

采用EGSB—SBR工艺处理实际果汁废水(COD 2 608~6 500 mg/L,p H 5.0~7.0)。在EGSB反应器成功启动及驯化完成的情况下,连续运行49 d。实验结果表明:第25天起,控制EGSB回流比为3.00∶1,EGSB反应器可在无须添加Na HCO3的条件下稳定运行,从而降低了废水处理成本;第25天起,平均进水COD,BOD5,SS分别为5 968,2 130,1 020 mg/L,平均出水COD,BOD5,SS分别降至131,11,50 mg/L,平均COD,BOD5,SS去除率分别为98%,99%,95%;组合工艺对该实际果汁废水具有良好的处理效果。     

EFFLUENT FEES,AN ALTERNATIVE SYSTEM FOR ACHIEVING WATER QUALITY: A CASE STUDY1

This paper reports the findings of a case study of the relative costs of a uniform standards system and an effluent fee system of water quality control. A 30-mile stretch of the Black Warrior River in Alabama is considered. The analysis demonstrates that the dischargers could reduce total pollution abatement costs by 33 percent under the suggested effluent fee system.     

EFFECTS OF MUNICIPAL WASTEWATER DISCHARGES ON AQUATIC COMMUNITIES,BOISE RWER,IDAHO1

ABSTRACT: Aquatic communities in the Boise River were examined from October 1987 to March 1988 to determine whether they were adversely affected by trace elements in effluents from two Boise wastewater treatment facilities. Trace-element concentrations in the Boise River were less than or near analytical-detection levels and were less than chronic toxicity criteria when detectable. Insect communities colonizing artificial substrates upstream and downstream from the wastewater treatment facilities were strongly associated, and coefficients of community loss indicated that effluents had benign enriching effects. The distributions of trace-element-intolerant mayflies indicated that trace-element concentrations in effluents did not adversely affect intolerant organisms in the Boise River. Condition factor of whitefish was significantly increased downstream from the Lander Street wastewater treatment facility and was significantly decreased downstream from the West Boise wastewater treatment facility.     

Bacterial pretreatment enhances removal of heavy metals during treatment of post-methanated distillery effluent by Typha angustata L

A combination of bacterial pretreatment followed by free water surface flow through wetland plants was investigated to determine its effect on removal of heavy metals in bioremediation of post-methanated distillery effluent (PMDE). The bacterial pretreatment was intended to transform the metal complexes and organic pollutants into simpler, biologically assimilable molecules. The 10% and 30% v/v concentrations of PMDE favored luxuriant bacterial growth; the 50% concentration supported less growth, whereas the undiluted effluent (i.e., 100%) supported very little bacterial growth. The use of bacterial pretreatment combined with the constructed wetland system greatly increase the overall bioaccumulation of all heavy metals by the plants compared with the control treatment. However, the integration of bacterial pretreatment of PMDE with the Typha angustata resulted in enhanced removal of Cd (34.02–61.50% increase), Cr (35.90–57.60% increase), Cu (32.88–54.22% increase), Fe (32.50–51.26% increase), Mn (35.99–82.85% increase), Ni (35.85–59.24% increase), Pb (33.45–59.51% increase) and Zn (31.95–53.70% increase) compared with a control that lacked this pretreatment. In addition to the bioaccumulation of these heavy metals, several physico-chemical parameters also improved at the 30% effluent concentration: color, BOD, COD, phenol and total nitrogen decreased by 98.33%, 98.89%, 98.50%, 93.75% and 82.39%, respectively, after 7 days of free water surface flow treatment. The results suggest that bacterial pretreatment of PMDE, integrated with phytoremediation will improve the treatment process of PMDE and promote safer disposal of this waste.     

基于机制设计理论的环境政策初探

机制设计理论是研究在市场失灵的情况下,如何设计一套机制达到既定社会目标的理论。而环境问题的特殊性质使得单纯依靠市场无法合理有效的解决环境问题,这就需要机制设计这一理论的指导。基于机制设计理论的原理,已探索出很多环境政策,有效的预防并解决了污染问题,使公众利益与社会的总体利益达到了“激励相容”。本文在以排污税、排污权交易等环境政策的设计为例,探讨了机制设计理论在环境政策制定中的应用,同时分析了机制设计理论存在的问题,指出在经济全球化的背景下,依靠机制设计理论解决环境问题遇到的瓶颈,提出了利用机制设计理论制定环境政策未来的可能方向和着力点。