污泥生物沥滤工艺优化和重金属分配研究

为了得到嗜酸硫细菌沥滤污泥中重金属的最佳工艺参数,对沥滤过程进行3因素4水平的正交实验研究。3种影响因素的水平设置分别为:污泥浓度35、25、15和5 g/L,单质硫投加量15、10、5和1 g/L,接种量15、10、5和3 g/L。对沥滤过程污泥中7种重金属(As、Cd、Cr、Cu、Ni、Pb和Zn)的去除率进行极差分析,提出了因素影响程度依次为单质硫投加量污泥浓度接种量,且最佳工艺条件为:污泥浓度25 g/L,单质硫投加量10 g/L,接种量为5%。采用超声波-离心方法,分步提取污泥胞外聚合物(EPS)的2种形态:松散结合态(LB)和紧密结合态(TB)。分析其中的重金属浓度,提出沥滤后重金属在污泥EPS的赋存以LB为主。     

磷酸铵镁法去除垃圾渗滤液中高浓度氨氮的研究

采用磷酸铵镁(MAP)法去除垃圾渗滤液中的高浓度氨氮,对影响氨氮去除率的各个因素进行了研究.结果表明,MgC12与K2 HPO4的组合对氨氮去除效果最好,各因素对氨氮去除率的影响为磷氮比(以摩尔比计,镁氮比同)＞初始pH＞搅拌时间＞搅拌速率＞镁氮比.通过单因素试验得到MAP法的适宜条件:磷氮比1.2,初始pH 9.50,搅拌时间4 min,搅拌速率100r/min,镁氮比1.1,此时氨氮的去除率可达90％左右.在此条件下,获得的MgNH4PO4·6H2O(即鸟粪石)沉淀具有良好的沉降性能和脱水性能,出水pH在7.2～7.4.对经MAP法预处理的垃圾渗滤液出水进行一段时间的生物处理,工艺运行稳定,不存在曝气孔堵塞问题.     

连续在线滤袋式淤泥脱水技术

以太湖淤泥为研究对象,研究了絮凝剂和滤袋性质对淤泥脱水性能的影响,并进行了滤袋脱水中试研究。结果表明,淤泥的含水率为90％时,在PAM和PAC最佳添加量55mg／L和1000mg／L条件下,淤泥比阻从8．7×10^7S2／g降低到2．0×10^7S2／g,Zeta电位从-28．77mV变成-4．68mV,滤袋平均过滤速度提高了137．9％,脱水性能显著提升。不同含水率下的实验得出了淤泥的最佳絮凝剂添加曲线;特殊材料滤袋相比于普通材料滤袋,滤袋的脱水综合能力大幅度提升,平均过滤速度达到0．479m^3／（m^2·h）,淤泥回收率为98．7％,泥饼含水率为71．6％;中试实验表明,淤泥经过4h过滤后,淤泥的含水率降到较低的65％,最终回收率可达到98．6％,滤液中污染物浓度满足国家排放标准。与传统技术相比,本技术具有脱水周期短、成本低、操作简单、安全性强等优点。     

废柴油再生工艺废弃物的固化实验

废弃油基钻井液中废柴油再生工艺产生的废渣废液具有高COD和高色度等特点,直接外排对环境危害严重。通过单因素实验和正交实验确定了该废弃物的最佳固化配方为:水泥∶粉煤灰为3∶2,水泥和粉煤灰加量30%,石膏加量1.5%,硫酸铝加量1.5%,石灰加量1%。在最佳固化配方下,废弃物浸出液的COD由10 062 mg/L降至62 mg/L,色度由500倍降至8倍,各主要污染指标都符合《污水综合排放标准》(GB 8978-1996)一级标准,固化成本约120元/m3。通过固化体的宏观照片和微观SEM照片对固化机理进行了分析,结果表明,废弃物被稳固地包裹在固化体之中。     

Residents' willingness to pay for improved liquid waste treatment in urban Ethiopia: results of choice experiment in Addis Ababa

This paper discusses residents’ willingness to pay (WTP) for improved liquid waste treatment in Addis Ababa based on data collected in 2011 using random parameter logit model. Findings indicate that respondents are willing to contribute for improved liquid waste treatment with higher quantity and quality. Their mean WTP for the medium improvement scenario is found to be 15.53 ETB (0.93 USD) per month. The compensation surplus tends to increase from the status quo to the alternative scenarios with aggressive improvement. Finally, the paper concludes by indicating the socioeconomic difference across households, and sub-cities need to be considered in designing environmental protection plans for the city.     

Knowledge Production and Learning for Sustainable Landscapes: Forewords by the Researchers and Stakeholders

This special issue of AMBIO presents a new approach to sustainability science that goes beyond interdisciplinary research. Using coupled natural and human systems, or landscapes, as multiple case studies in Europe’s East and West knowledge production and learning toward transdisciplinary research was applied in Sweden, countries in Central and Eastern Europe, and Russia. First, the research group Forest-Landscape-Society summarizes the research program (2005–2012) behind this special issue of AMBIO and its development to participate in transdisciplinary research. Second, stakeholders at multiple levels provide their views on the new approach presented and reported.     

Long-term dynamics of the atrazine mineralization potential in surface and subsurface soil in an agricultural field as a response to atrazine applications

The dynamics of the atrazine mineralization potential in agricultural soil was studied in two soil layers (topsoil and at 35-45 cm depth) in a 3 years field trial to examine the long term response of atrazine mineralizing soil populations to atrazine application and intermittent periods without atrazine and the effect of manure treatment on those processes. In topsoil samples, ¹⁴C-atrazine mineralization lag times decreased after atrazine application and increased with increasing time after atrazine application, suggesting that atrazine application resulted into the proliferation of atrazine mineralizing microbial populations which decayed when atrazine application stopped. Decay rates appeared however much slower than growth rates. Atrazine application also resulted into the increase of the atrazine mineralization potential in deeper layers which was explained by the growth on leached atrazine as measured in soil leachates recovered from that depth. However, no decay was observed during intermittent periods without atrazine application in the deeper soil layer. atzA and trzN gene quantification confirmed partly the growth and decay of the atrazine degrading populations in the soil and suggested that especially trzN bearing populations are the dominant atrazine degrading populations in both topsoil and deeper soil. Manure treatment only improved the atrazine mineralization rate in deeper soil layers. Our results point to the importance of the atrazine application history on a field and suggests that the long term survival of atrazine degrading populations after atrazine application enables them to rapidly proliferate once atrazine is again applied.     

石灰岩和砂岩地区豆科类植物紫花光叶苕(Vicia villosa)中铁和锰的不同分配模式

豆科类植物生物量的减少主要与氮和磷之间的平衡受到影响而有紧密的相关性。然而,其他营养元素之间的不平衡也能响应生物量的减少,比如铁和锰营养元素。选择了贵州茂兰相邻的石灰岩和砂岩地区土壤进行了野外种植实验。实验结果表明:生长着的豆科类植物铁(Fe)和锰(Mn)出现互为相反的分配模式:在砂岩地区生长的豆科类植物根部对铁的吸收相对高于石灰岩地区;而对锰的吸收,石灰岩地区高于砂岩地区。因此,植物根部的Fe∶Mn,砂岩地区高于石灰岩地区。这个结果说明豆科类植物根部对Fe和Mn的吸收存在不同模式。然而,在叶片中的Fe∶Mn砂岩地区和石灰岩地区之间基本没有区别,这说明铁和锰从根部到叶片的迁移具有不同模式。当叶片的Fe∶Mn(质量之比)低于2.9时,有可能响应豆科类植物生物量的减少。我们在研究植物与土壤的营养元素含量之间相关性时,越过环境因素,必须考虑植物内部随生长过程而发生变化的营养元素的化学计量,比如,生长着的植物中Fe∶Mn比值的变化等。     

多维电极法处理高色度活性染料模拟废水影响因素分析

以活性嫩黄K 4G染料模拟废水为处理对象 ,采用多维电极法 ,考查了各种因素对多维电极系统处理活性染料时的脱色率、CODCr降解率的影响 ,结果表明 ,增多活性炭量、增大电流密度、延长电解时间和加入铁屑 ,都能使脱色率和CODCr降解率得到提高 ,电导率的变化对脱色率和CODCr降解率有一定影响。利用正交实验比较了各因素的相对影响大小     

生物质气化发电厂洗焦废水生物处理的中试研究

为使生物质气化发电厂的洗涤废水得到有效的循环使用,在以废陶瓷片作为填料的生物膜反应器中,接种优势菌,对经过物化预处理的生物质气化洗涤废水进行处理,着重考察了不同工艺条件下,生物膜反应器对废水的处理效果.采用缺氧20h,好氧10h的处理工艺,可有效降低该废水的COD,当进水COD为584～923mg·L-1时,出水COD达到118 5～230 2mg L-1,COD的平均下降率为78 6%.