Metal distribution characteristic of MSWI bottom ash in view of metal recovery

Bottom ash is the major by-product of municipal solid waste incineration(MSWI), and is often reused as an engineering material, such as road-base aggregate. However, some metals(especially aluminum) in bottom ash can react with water and generate gas that could cause expansion and failure of products containing the ash; these metals must be removed before the ash is utilized. The size distribution and the chemical speciation of metals in the bottom ash from two Chinese MSWI plants were examined in this study, and the recovery potential of metals from the ash was evaluated. The metal concentrations in these bottom ashes were lower than that generated in other developed countries. Specifically, the contents of Al,Fe, Cu and Zn were 18.9–29.2, 25.5–32.3, 0.7–1.0 and 1.6–2.5 g/kg, respectively. Moreover,44.9–57.0 wt.% of Al and 55.6–75.4 wt.% of Fe were distributed in bottom ash particles smaller than 5 mm. Similarly, 46.6–79.7 wt.% of Cu and 42.9–74.2 wt.% of Zn were concentrated in particles smaller than 3 mm. The Fe in the bottom ash mainly existed as hematite, and its chemical speciation was considered to limit the recovery efficiency of magnetic separation.     

Performance and microbial community of a membrane bioreactor system——Treating wastewater from ethanol fermentation of food waste

In this study, a lab-scale biological anaerobic/anaerobic/anoxic/membrane bioreactor(A_-~3MBR) was designed to treat wastewater from the ethanol fermentation of food waste,a promising way for the disposal of food waste and reclamation of resources. The 454 pyrosequencing technique was used to investigate the composition of the microbial community in the treatment system. The system yielded a stable effluent concentration of chemical oxygen demand(202 ± 23 mg/L), total nitrogen(62.1 ± 7.1 mg/L), ammonia(0.3 ±0.13 mg/L) and total phosphorus(8.3 ± 0.9 mg/L), and the reactors played different roles in specific pollutant removal. The exploration of the microbial community in the system revealed that:(1) the microbial diversity of anaerobic reactors A_1 and A_2, in which organic pollutants were massively degraded, was much higher than that in anoxic A_3 and aerobic MBR;(2) although the community composition in each reactor was quite different, bacteria assigned to the classes Clostridia, Bacteroidia, and Synergistia were important and common microorganisms for organic pollutant degradation in the anaerobic units, and bacteria from Alphaproteobacteria and Betaproteobacteria were the dominant microbial population in A_3 and MBR;(3) the taxon identification indicated that Arcobacter in the anaerobic reactors and Thauera in the anoxic reactor were two representative genera in the biological process. Our results proved that the biological A_-~3MBR process is an alternative technique for treating wastewater from food waste.     

添加动物源氨基酸水解液研制生物有机肥

为改善生物有机肥性质,提高生物有机肥质量,采取在生物有机肥中添加外源氨基酸水解液以提升生物有机肥中功能微生物的数量.以病死猪酸解制得氨基酸水解液为生物有机肥外加原料,研究了氨基酸水解液添加量、有机肥种类（鸡粪、牛粪、中药渣）、发酵时间对功能菌株SQR9数量的影响.结果表明:当氨基酸水解液添加量为20%时固体发酵效果优于其他接种量,预发酵3 d后接种SQR9的功能菌数量明显高于未预发酵直接接菌,预发酵中肥料（以干质量计,下同）的最高功能菌数量可达4×108 CFU/g,而第0天接菌时肥料的最高功能菌数量仅为1.2×108 CFU/g.以腐熟鸡粪、牛粪、中药渣堆肥为载体,添加酸解氨基酸研制生物有机肥的最优接菌量分别为10.0%、7.5%、10.0%;SQR9菌株生长的最佳含水量为40%.此外,氨基酸水解液的添加可提高生物有机肥的w（TN）.研究显示,氨基酸水解液的添加能有效促进固态发酵过程中功能菌株数量的增加.      

我国工业危险废物的来源、处理及监管对策与建议

通过大量环境统计数据的分析,对我国工业危险废物的产生、综合利用、处置和贮存,从行业来源、区域分布进行了分析和总结。结合我国工业危险废物企业自建设施和政府集中处理设施处理情况,对我国工业危险废物的处理和环保监管对策提出了若干建议。     

我国工业危险废物的来源、处理及监管对策与建议

通过大量环境统计数据的分析,对我国工业危险废物的产生、综合利用、处置和贮存,从行业来源、区域分布进行了分析和总结。结合我国工业危险废物企业自建设施和政府集中处理设施处理情况,对我国工业危险废物的处理和环保监管对策提出了若干建议。     

危险废物焚烧厂环境污染控制与风险管理水平评价指标体系研究与应用

采用德尔菲法、层次分析法和五分制综合评分法,构建了危险废物焚烧厂环境污染控制与风险管理水平评价指标体系。从选址、技术和管理的角度,制定了31个评价指标,并归纳为8个准则层指标群,通过计算权重和对评价指标的赋分,实现对危险废物焚烧厂环境污染控制与风险管理水平的量化评价。应用结果表明:华南某市两家危险废物焚烧厂的环境污染控制与风险管理水平分值分别为3.34和4.38,分别处于良好和先进的水平。     

中国村镇生活垃圾的养分与重金属含量特征及其农用潜力分析

对全国12个省份72个典型村镇进行了生活垃圾采样调查,系统分析了我国农村生活垃圾的基本理化特性、养分含量与重金属特征及其农用潜力。研究表明:我国典型村镇生活垃圾含水率为(53.68±8.84)%,p H为7.11±0.56,有机质含量为(49.04±10.49)%,C/N约为43∶1,C/P约为144∶1。除C/N略高外,其余特性均适合进行堆肥化处置。我国典型村镇生活垃圾中重金属As、Hg、Pb、Cd、Cr,Cu和Zn含量分别为(7.645±8.729),(0.737±0.480),(21.798±17.606),(3.356±11.012),(108.632±84.011),(36.834±10.905),(80.093±42.237)mg/kg。与国内相关标准相比,只有Hg、Cd超标,最大超标率分别为29.17%、43.75%;与欧美相关标准相比,仅有Cd、Cr超标,最大超标率分别为25.69%、37.50%。     

西安市建筑垃圾渣土资源再利用研究

建筑垃圾渣土作为"建筑副产品",已造成严重的城市环境问题。通过对西安市建筑垃圾渣土的现场调查及工程再利用,借鉴发达国家及国内省市建筑垃圾渣土的成功管理经验和资源再利用的成功范例,提出了西安建筑垃圾资源再利用的对策建议,对"十三五"期间减少已有建筑垃圾的存量并遏制增量和建设西安森林城市具有参考意义。     

小城镇产业集群主要污染源筛查与影响分析

以郫县安德镇川菜产业园为研究对象,采用等标污染负荷法对污染影响进行了标准化评价。结果发现:川菜产业园主要的工业污染行业为豆制品加工行业,排污量为2 919.94 t/a,占总排污量的96.46%,等标污染负荷为9.83,占总污染负荷的92.83%,其中有6家企业为主要控制对象。对比分析发现,环境污染受企业规模、末端处理方式、废水排放量等多方面因素共同影响。所有污染因子中,BOD对环境的实质污染影响较大。该研究成果将为优化小城镇产业集群的规划、管理和污染物总量控制提供有价值的参考。     

餐厨垃圾厌氧消化运行试验研究

采用猪粪厌氧消化的消化污泥为接种物,在中温(37℃)条件下,以连续进料的方式对餐厨垃圾的湿式厌氧消化进行了启动以及运行试验,监测整个实验过程中产气量、pH、VFA、碱度等能够反映厌氧消化的系统指标。结果表明:本实验中系统最佳有机负荷为2.8 kg/(m~3·d)(以VS计),超过此负荷后,依靠系统自身恢复和人工调节,pH很难恢复正常运行状态。正常运行过程中,pH稳定在7.5~8.0,VFA稳定在2 000 mg/L左右,碱度在6 000~9 000 mg/L,氨氮在1 500~2 000 mg/L,底物含水率为96%~98%。系统超负荷运行后,产气量和pH下降,VFA浓度上升,碱度、氨氮、含水率基本保持稳定。