Greenhouse gas emissions from a constructed wetland for municipal sewage treatment

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苎麻(B.nivea(L).Gaud)对土壤Cd的吸收及其生物净化效应

通过４年微区定位试验，研究了苎麻对土壤Ｃｄ的吸收及其净化效应。结果发现，苎麻地上部分年生物产量（ＹＢ）与土壤Ｃｄ含量）（Ｓｃ）的关系可用对数函数模型ＬｏｇＹＢ＝３．３８７４－０．０７５３（ＬｏｇＳｃ）＾２描述；     

降低城市生活垃圾焚烧发电设施建设与运行费用的本土化方法研究

城市生活垃圾焚烧发电技术是比较完善的城市生活垃圾处理与资源综合利用方法 ,其推广应用的困难在于建设与运行费用较高。本文分析费用较高的原因 ,提出设备本土化是最好的降低费用方法 ,并分析了城市生活垃圾焚烧发电设备本土化的基础、必要性、可行方案、成功实例以及现行政策及发展趋向 ,可供城市生活垃圾焚烧发电设施建设、运行方案及相关政策决策人员参考     

交联菌丝体吸附剂的制备及其对Cr3+的吸附特性

深入研究了交联菌丝体吸附剂的制备工艺及其对Cr3+的吸附特性.交联菌丝体吸附剂制备工艺简单,但在制备过程中,活化剂NaOH和交联剂的用量对吸附特性影响较大.与纯菌丝体吸附剂相比,交联菌丝体吸附剂表观吸附容量提高48%,达到49.83 mg/g(pH=2.53,水溶液中的Cr3+浓度为600mg/L),同时其机械强度明显增强.交联菌丝体吸附剂对Cr3+的吸附特点是将沉淀法与吸附法相结合,将沉淀与吸附两过程合二为一,从而简化了处理工艺,降低了处理成本.     

Effects of disinfection efficiency on microbial communities and corrosion processes in drinking water distribution systems simulated with actual running conditions

The effects of disinfection efficiency on microbial communities and the corrosion of cast iron pipes in drinking water distribution systems (DWDSs) were studied. Two annular reactors (ARs) that simulated actual running conditions with UV/Cl₂ disinfection and chlorination alone were used. High chlorine consumption and corrosion rate were found in the AR with UV/Cl₂. According to functional genes and pyrosequencing tests, a high percentage of iron recycling bacteria was detected within the biofilm of the AR with Cl₂ at early running stage, whereas siderophore-producing bacteria were dominant in the biofilm of the AR with UV/Cl_2. At the early running stage, the sequential use of UV light and an initial high chlorine dosage suppressed the biomass and iron-recycling bacteria in both bulk water and biofilms, thereby forming less protective scales against further corrosion, which enhanced chlorine consumption. Non-metric multidimensional scaling analysis showed that the bacterial communities in the ARs shaped from within rather than being imported by influents. These results indicate that the initial high disinfection efficiency within the distribution system had not contributed to the accumulation of iron-recycling bacteria at the early running stages. This study offer certain implications for controlling corrosion and water quality in DWDSs.     

Controlled synthesis of Zeolite adsorbent from low-grade diatomite: A case study of self-assembled sodalite microspheres

Highly efficient and sustainable conversion technologies to generate uniform sodalite(Na_8(AlSiO_4)_6(OH)_2) zeolite micro spheres with low-grade waste natural diatomite as raw materials via a solution-mediated crystallization route were developed in the present study.The synthesis process can be considered as an in-situ zeolitization of diatomite precursor without involving any me so scale template and any post-synthetic modification.The mass ratios of diatomite and AlCl_3·6 H_2 O have remarkable effect on the morphology,crystal structure and porosity of sodalite zeolite product.The preferred sodalite microspheres with uniform mesoporous of size 3.5-5.5 nm and large surface area of 162.5 m2/g exhibit well removal performance for heavy metal ions(Pb(II),Cd(II),Zn(II),and Cu(II)),with the highest adsorption abilities for Pb(II) ions of 365 mg/g.In addition,the effect of contact time,initial ion concentration,competitive adsorption and solution pH were evaluated.The removal performance results from synergistic effects of dominating cation-exchange and additional surface chemisorption.The study may broadly help unveil chemical control reactions of the zeolitization processes of diatomite,and thus facilitates the development of promising zeolite materials for the use in natural and engineered aquatic environments by recvcling waste diatomite resources.     

Combined zero valent iron and hydrogen peroxide conditioning significantly enhances the dewaterability of anaerobic digestate

The importance of enhancing sludge dewaterability is increasing due to the considerable impact of excess sludge volume on disposal costs and on overall sludge management. This study presents an innovative approach to enhance dewaterability of anaerobic digestate(AD) harvested from a wastewater treatment plant. The combination of zero valent iron(ZVI, 0–4.0 g/g total solids(TS)) and hydrogen peroxide(HP, 0–90 mg/g TS) under pH 3.0 significantly enhanced the AD dewaterability. The largest enhancement of AD dewaterability was achieved at 18 mg HP/g TS and 2.0 g ZVI/g TS, with the capillary suction time reduced by up to 90%. Economic analysis suggested that the proposed HP and ZVI treatment has more economic benefits in comparison with the classical Fenton reaction process. The destruction of extracellular polymeric substances and cells as well as the decrease of particle size were supposed to contribute to the enhanced AD dewaterability by HP + ZVI conditioning.     

一株降解乐果的高效菌的分离和鉴定

从乐果合成废水生化处理的活性污泥中分离出27株具有不同程度的降解乐果能力的好氧菌株。经降解功能测定试验,获得一株降解能力高的菌株(编号5724),24小时内,对乐果降解率达57％—58％。其主要特征为;细胞杆状,革兰氏阴性,直径0.7—1.2×1.4—4.2μm,具一根极生鞭毛,能运动,胞内有聚—β—羟基丁酸颗粒,葡萄糖的O/F测定产碱、氧化酶、接触酶均为阳性,甜菜碱不利用,明胶不液化,硝酸盐还原阳性,最适生长温度为30—35℃,3℃和41℃时生长极弱。48—52℃不生长,最适生长pH6.5—7,pH4以下不生长。按照上述特征,根据《伯杰氏细菌学鉴定手册》鉴定表,该菌株属类产碱假单胞菌(Pseudomonaspseudoalcaliges)。     

海泡石在废水处理中的应用研究

海泡石是一种纤维状含水的镁硅酸盐矿石 ,具有良好的吸附性能。纺织印染废水的组分异常复杂 ,是较难处理的废水之一。利用江西乐平产的海泡石对纺织印染废水进行了试验研究 ,实验结果表明 ,脱色率 >90 % ,CODCr去除率为70 %— 80 % ,其吸附容量为 30 7%。     

Dissolution and removal of PAHs from a contaminated soil using sunflower oil

This study reports on the feasibility of remediation of polycyclic aromatic hydrocarbon (PAH) contaminated soils using sunflower oil, an environmentally-friendly solvent. Batch experiments were performed to test the influence of oil/soil ratio on the remediation of PAH contaminated soil, and to test the mass transfer behaviors of PAHs from soil to oil. An empirical model was employed to describe the kinetics of PAH dissolution and to predict equilibrium concentrations of PAHs in oil. PAH containing oil was regenerated using active carbon. Results show that dissolution of PAHs from a Manufactured Gas Plant (MGP) soil at oil/soil ratios of one or two were almost the same. Nearly all PAHs (81-100%) could be removed by sunflower oil dissolution. Mass transfer coefficients for low molecular PAHs namely fluoranthene, phenanthrene and anthracene were one or two orders of magnitude higher than those for high molecular PAHs with 4-6 rings. Ninety milliliters of PAH containing oil could be regenerated by 10 g active carbon in a batch reactor. Such a remediation procedure indicates that sunflower oil is a promising agent for the removal of PAHs from MGP soils. However, further research is required before the method can be used for in situ remediation of contaminated sites.