Biofilm formation and microbial community analysis of the simulated river bioreactor for contaminated source water remediation

Background, aim, and scope

The start-up pattern of biofilm remediation system affects the biofilm characteristics and operating performances. The objective of this study was to evaluate the performances of the contaminated source water remediation systems with different start-up patterns in view of the pollutants removal performances and microbial community succession.

Methods

The operating performances of four lab-scale simulated river biofilm reactors were examined which employed different start-up methods (natural enrichment and artificial enhancement viadischarging sediment with influent velocity gradient increase) and different bio-fillers (Elastic filler and AquaMats? ecobase). At the same time, the microbial communities of the bioreactors in different phases were analyzed by polymerase chain reaction, denaturing gradient gel electrophoresis, and sequencing.

Results and discussion

The pollutants removal performances became stable in the four reactors after 2 months?? operation, with ammonia nitrogen and permanganate index (COD_Mn) removal efficiencies of 84.41?C94.21% and 69.66?C76.60%, respectively. The biomass of mature biofilm was higher in the bioreactors by artificial enhancement than that by natural enrichment. Microbial community analysis indicated that elastic filler could enrich mature biofilm faster than AquaMats?. The heterotrophic bacteria diversity of biofilm decreased by artificial enhancement, which favored the ammonia-oxidizing bacteria (AOB) developing on the bio-fillers. Furthermore, Nitrosomonas- and Nitrosospira-like AOB coexisted in the biofilm, and Pseudomonas sp., Sphaerotilus sp., Janthinobacterium sp., Corynebacterium aurimucosum were dominant in the oligotrophic niche.

Conclusion

Artificial enhancement via the combination of sediment discharging and influent velocity gradient increasing could enhance the biofilm formation and autotrophic AOB enrichment in oligotrophic niche.     

Environmental lead pollution threatens the children living in the Pearl River Delta region, China

Introduction and purpose

The objective of this study is to determine children??s blood lead levels and identify sources of lead exposure. Childhood lead exposure constitutes a major pediatric health problem today in China. A blood lead screening survey program for children in the age group of 2?C12?years residing in Pearl River Delta region, south of China, was carried out from Dec 2007 to Jan 2008.

Methods

Blood lead levels and lead isotope ratios of a total of 761 participants were assessed by inductively coupled plasma mass spectroscopy. Measurements of urban environmental samples for source identification of children lead exposure were also performed.

Results and conclusions

The geometric mean value of the children??s blood lead levels was 57.05???g/L, and 9.6% of them were higher than 100???g/L. The blood lead levels were still much higher than those in developed countries. Based on the data of environmental lead source inventories, lead isotopic tracing revealed that there is about 6.7% past used gasoline Pb embedded in Shenzhen residential dust and about 15.6% in Guangzhou dust, respectively.     

不同粒径零价铁（ZVI）对污水污泥H_2S和CH_4释放速率的影响

考察了不同粒径零价铁（ZVI）,包括200目普通铁粉（200m-ZVI）、800目超细铁粉（800m-ZVI）和纳米铁粉（nZVI,粒径=20 nm）,对污水污泥的硫化氢和甲烷释放速率的影响。研究发现：（1）在22 d内,添加0.1%的200m-ZVI使污泥的硫化氢释放速率提高48.0%,而添加0.1%的800-ZVI和nZVI,则使污泥的硫化氢释放速率分别降低33.1%和77.1%;（2）不同粒径ZVI均可以提高污泥沼气中的甲烷浓度,且依次为nZVI〉800m-ZVI〉200m-ZVI;（3）在23 d内,添加0.1%的200m-ZVI和nZVI使污泥的甲烷累计产生量分别提高了15.5%和40.6%,而添加0.1%800m-ZVI则使甲烷产生量降低了12.5%。nZVI可以有效控制污泥的硫化氢释放,并显著提升污泥在厌氧发酵过程的产甲烷速率。     

曝气和pH对城市污染河道底泥氮形态的影响

以城市重污染河道表层沉积物为研究对象,采用模拟实验方法,探讨了不同曝气方式(水曝气和泥曝气)、上覆水初始pH(自然状态pH=7和pH=11)对城市污染河道底泥氮形态的影响。结果表明:采用水曝气+pH11方式对城市重污染河道上覆水、间隙水中总氮去除率分别为70.03%和44.66%;泥曝气+pH7方式对上覆水、间隙水、底泥中氨氮去除率分别为94.31%、84.07%和68.29%;底泥pH与上覆水总氮浓度呈正相关(p<0.05);泥曝气+pH11方式使底泥含水率、烧失率明显升高,继而影响各形态氮在泥水系统中的赋存,其中底泥吸附态氨氮含量与底泥含水率呈显著负相关(p<0.01),间隙水可溶态氨氮浓度与底泥烧失率显著正相关(p<0.01)。     

液相色谱-质谱法测定水中氨基甲酸酯类农药及其代谢物

建立了直接测定水中10种氨基甲酸酯类农药及其代谢物的超高效液相色谱-质谱分析方法。该方法对水样无需进行富集处理,水样过滤后就可以直接测定。实验结果表明:测定液中各氨基甲酸酯类农药及其代谢物的质量浓度与离子对峰面积在质量浓度0.5～1 000.0μg/L内具有良好的线性关系;方法检出限为0.1～5.0μg/L;加标回收率91%～103%;相对标准偏差为2%～5%。该方法具有简便快捷、灵敏度高的特点。     

Cost-Effectiveness of Payments for Ecosystem Services with Dual Goals of Environment and Poverty Alleviation

The goal of this article is to understand strategies by which both the environmental and poverty alleviation objectives of PES programs can be achieved cost effectively. To meet this goal, we first create a conceptual framework to understand the implications of alternative targeting when policy makers have both environmental and poverty alleviation goals. We then use the Grain for Green program in China, the largest PES program in the developing world, as a case study. We also use a data set from a survey that we designed and implemented to evaluate the program. Using the data set we first evaluate what factors determined selection of program areas for the Grain for Green program. We then demonstrate the heterogeneity of parcels and households and examine the correlations across households and their parcels in terms of their potential environmental benefits, opportunity costs of participating, and the asset levels of households as an indicator of poverty. Finally, we compare five alternative targeting criteria and simulate their performance in terms of cost effectiveness in meeting both the environmental and poverty alleviation goals when given a fixed budget. Based on our simulations, we find that there is a substantial gain in the cost effectiveness of the program by targeting parcels based on the “gold standard,” i.e., targeting parcels with low opportunity cost and high environmental benefit managed by poorer households.     

层燃螺旋炉排焚烧技术处理含油污泥研究

通过对几种含油污泥无害化处理技术的比选,分析不同处理技术物耗、能耗情况,优选出经济有效的含油污泥焚烧技术,结合新疆油田含油污泥的特点,采用层燃螺旋炉排焚烧技术,利用其燃烧热能生产蒸汽用于原油生产,采用余热吸收急冷与碱液半干法除酸技术,有效控制了二次污染;采用布袋除尘与烟尘固化技术确保了烟气达标排放。年节省成本支出3095.88万元。     

Carbon/nitrogen ratio as a major factor for predicting the effects of organic wastes on soil bacterial communities assessed by DNA-based molecular techniques

Background, aim, and scope  

Current Australian legislation permits the beneficial application of grease trap waste (GTW) to agricultural soil, viewing it as a beneficial source of organic matter and soil conditioner containing no/low amounts of metals or pathogenic organisms. However, little is known about the influence of GTW on soil bacterial community. A field experiment was established at Menangle in south western Sydney in Australia to quantitatively assess the impacts of different types (GTW CO and GTW CL) and amounts of GTW application on the soil bacterial community and diversity. Furthermore, a municipal solid waste (MSW) compost was simultaneously examined to compare against the other organic wastes. Knowledge about the shifts in microbial community structure and diversity following the applications of organic wastes could help to evaluate the ecological consequences on the soil and thus to develop sound regulatory guidelines for the beneficial reuse of organic wastes in agricultural lands.     

Comprehensive evaluation of municipal garbage disposal in Changchun City by the strategic environmental assessment

Purpose

The environmental issues caused by the municipal solid waste disposal are becoming a worldwide concern.

Methods

We studied the situations both domestically and abroad by the strategic environmental assessment (SEA) approach and also conducted comprehensive evaluations of garbage disposal in Changchun City.

Results

On the basis of this study, we found that SEA is of great importance in the municipal solid waste disposal. Moreover, with the rapid socioeconomic development of Changchun City, municipal solid waste production increases on an annual basis, and thus, good waste management planning is of great significance.

Conclusions

Considering the situation of the economic development of Changchun City, garbage disposal was handled mainly in the major sanitary landfills with appropriate use of incineration technology. This plan is environmentally friendly at a relatively high degree and has met the requirements of minimum investment. It also takes into account the requirements of the development of incineration technology. Regarding environmental pollution in terms of groundwater pollution and atmospheric pollution, this plan is a feasible one by meeting various requirements with low environmental impact among the three plans discussed in this study.     

Carbon dioxide and methane fluxes in the littoral zones of two lakes,east Antarctica

During the summertime of 2007/2008, carbon dioxide (CO₂) and methane (CH₄) fluxes across air–water interface were investigated in the littoral zones of Lake Mochou and Lake Tuanjie, east Antarctica, using a static chamber technique. The mean fluxes of CO₂ and CH₄ were ?70.8 mgCO₂ m^?2 h^?1 and 144.6 μgCH₄ m^?2 h^?1, respectively, in the littoral zone of Lake Mochou; The mean fluxes were ?36.9 mgCO₂ m^?2 h^?1 and 109.8 μgCH₄ m^?2 h^?1, respectively, in the littoral zone of Lake Tuanjie. Their fluxes showed large temporal and spatial dynamics. The CO₂ fluxes showed a significantly negative correlation with daily total radiation (DTR) and a weakly negative correlation with air temperature and water temperature, indicating that sunlight intensity controlled the magnitude of CO₂ fluxes from the open lakes. The CH₄ fluxes significantly correlated with local air temperature, water table and total dissolved solids (TDS), indicating that they were the predominant factors influencing CH₄ fluxes. Summertime CO₂ budgets in the littoral zones of Lake Mochou and Lake Tuanjie were estimated to be ?152.9 gCO₂ m^?2 and ?79.7 gCO₂ m^?2, respectively, and net CH₄ emissions were estimated to be 312.3 mgCH₄ m^?2 and 237.2 mgCH₄ m^?2, respectively. Our results show that shallow, open, alga-rich lakes might be strong summertime CO₂ absorbers and small CH₄ emitters during the open water in coastal Antarctica.