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Indigenous microbes play crucial roles in arsenic mobilization in high arsenic groundwater systems. Databases concerning the presence and the activity of microbial communities are very useful in evaluating the potential of microbe-mediated arsenic mobilization in shallow aquifers hosting high arsenic groundwater. This study characterized microbial communities in groundwaters at different depths with different arsenic concentrations by DGGE and one sediment by 16S rRNA gene clone library, and evaluated arsenic mobilization in microcosm batches with the presence of indigenous bacteria. DGGE fingerprints revealed that the community structure changed substantially with depth at the same location. It indicated that a relatively higher bacterial diversity was present in the groundwater sample with lower arsenic concentration. Sequence analysis of 16S rRNA gene demonstrated that the sediment bacteria mainly belonged to Pseudomonas, Dietzia and Rhodococcus, which have been widely found in aquifer systems. Additionally, NO3 −-reducing bacteria Pseudomonas sp. was the largest group, followed by Fe(III)-reducing, SO4 2−-reducing and As(V)-reducing bacteria in the sediment sample. These anaerobic bacteria used the specific oxyanions as electron acceptor and played a significant role in reductive dissolution of Fe oxide minerals, reduction of As(V), and release of arsenic from sediments into groundwater. Microcosm experiments, using intact aquifer sediments, showed that arsenic release and Fe(III) reduction were microbially mediated in the presence of indigenous bacteria. High arsenic concentration was also observed in the batch without amendment of organic carbon, demonstrating that the natural organic matter in sediments was the potential electron donor for microbially mediated arsenic release from these aquifer sediments.

In this study, pyrite-based denitrification using untreated pyrite (UP) and acid-pretreated pyrite (AP) was evaluated as an alternative to elemental sulfur based denitrification. Pyrite-based denitrification resulted in a favorable nitrate removal rate constant (0.95 d(-1)), sulfate production of 388.00 mg/L, and a stable pH. The pretreatment of pyrite with acid led to a further increase in the nitrate removal rate constant (1.03 d(-1)) and reduction in initial sulfate concentration (224.25±7.50 mg/L). By analyzing the microbial community structure using Denaturing Gradient Gel Electrophoresis, it was confirmed that Sulfurimonas denitrificans (S. denitrificans) could utilize pyrite as an electron donor. A stable pH was observed over the entire experimental period, indicating that the use of a pH buffer reagent would not be necessary for pyrite-based denitrification. Therefore, pyrite could effectively replace elemental sulfur as an electron donor in autotrophic denitrification for nitrate-contaminated groundwater remediation.

A heterotrophic/biofilm-electrode autotrophic denitrification reactor (HAD-BER) was developed to improve denitrification efficiency and reduce the consumption of organic carbon source. Maximum nitrate removal efficiency of 99.9% was gained under the optimum current density of 200 mA/m(2). The number of heterotrophic denitrification bacteria (HDB) 2.0 × 10(5) and hydrogen autotrophic denitrification bacteria (ADB) 2.0 × 10(3) in per milliliter biofilm solution were observed by the most probable number (MPN) culture, demonstrating that HDB and ADB coexist in the HAD-BER. The inorganic carbon source for autotrophic denitrification was supplied by the dissolved carbon dioxide (CO2) evolved from the heterotrophic denitrification process, indicating that there was synergistic interaction between the HDB and ADB, i.e., the organic carbon source used for denitrification could be decreased in the HAD-BER. Therefore, the developed HAD-BER would be a promising approach for nitrate removal from groundwater.

We characterized eukaryotic community structure and the relationship between the community structure and environmental factors in acidic mine drainage (AMD) lake of a sulfide mine in Anhui Province, China.The 18S rRNA gene clone libraries were constructed by using molecular biology techniques to analyze the eukaryotic phylogenetic relationships, and the canonical correspondence analysis (CCA) was used to analyze the relationship between the community structure and environmental factors.The phylogenetic analysis shows that Ascomycota is widespread in the four samples and dominated in the AMD-1 and AMD-3 clone libraries, whereas Chlorophyta and Basidiomycota are the predominant in AMD-2 and AMD-4 samples, respectively. Moreover, many sequences in libraries were closely related to those of acid-resisting and metal-resisting eukaryotic microbes, such as Sarcinomyces petricola, Penicillium janthinellum, Coniochaeta velutina, Trichoderma viride, Chlorella protothecoides var. acidicola, Ochromonas sp., and there are high content of known human pathogens, such as Lecythophora hoffmannii, Cryptococcus neoformans. CCA analysis revealed that the critical factors influencing the eukaryotic community structure include TN, SO4(2-), Fe2+ and Eh.Difference of eukaryotic community structure in time and spare may be related with physico-chemical properties of acidic mine drainage. High content of human pathogens was detected in the acidic ecosystem. The ecological study of eukaryotes under the acidic conditions can help to find efficient methods to process acid mine drainage.

In this study, we have investigated the effect of pollutants removal of a vertical multilevel soil infiltration (VMSI) system on municipal wastewater treatment. The VMSI was of 30cm*20cm*50cm column, in which combined stuffing consisted of soil, quartz sand, active carbon and scrap irons were packed. As a result, VMSI system exhibited excellent removal efficiency with 91.7% of COD, 98.4% of NH4+-N, 81.0% of TN and 97.3% of TP. Moreover, the proportion of biological and abiological effects in pollutants removal was also investigated through different reactor, and abiological effect against organic removal was 53-62%. In a long-term performance, the VMSI system exhibited excellent ability and stability in pollutants removal.

To understand the composition and structure of microbial communities in acid (pH 3.0) mine drainage (AMD) associated with pyrite mine tailings in Anhui Province, China, molecular diversities of 16S rRNA and 18S rRNA genes were examined using a PCR-based cloning approach. Bacterial, archaeal and microeukaryotic clone libraries were constructed. In contrast to typical dominance of autotrophic acidophiles, genus Acidiphilium, which consists of mixotrophic acidophiles capable of chemoorganotrophic and photosynthetic metabolisms, was the largest group in the bacterial clone library. These mixotrophic organisms may be advantageous in the oligotrophic AMD environment of the study site (certain amounts of dissolved organic carbon and light) by switching between two modes of metabolisms. Unexpectedly, a large fraction of bacterial clones (12.7%) were related to the neutrophilic genus Legionella, which can cause Legionnaires’ disease, a potentially lethal pneumonia. The eukaryotic 18S rRNA gene sequences were mostly related to Oxytricha, Nuclearia, and Penicillium. In the archaeal clone library, all the sequences were affiliated to the phylum Crenarchaeota, while the Euryarchaeota was not present.

Soil infiltration treatment was proved to be an effective and low-cost treatment technique for municipal wastewater in many areas. This system was intensified by combined stuffing (with zeolite, active carbon, sawdust and scrap iron) set for multilevel and named Vertical Multilevels Soil infiltration system (VMSI). Bench-scale soil column experiments were performed in laboratory to investigate effects for this kind of system. From the start-up to the 4th month, VMSI exhibited effective pollutants removals after maturation, with the highest removal efficiency 88% of chemical oxygen demand (COD), the highest removal efficiency 94% of total nitrogen (TN). Bench-scale soil column experiments were performed in parallel to compare aeration with non-aeration effects of this system, and found that removal efficiency of nitrate nitrogen(NO3 - -N) of the aeration columns were higher than the columns with non-aeration, it was also found that removal efficiency of nitrate nitrogen had direct relations with soil content. The objective of this paper was concentrate on pollutants removal by a VMSI system for the treatment of municipal wastewater.

Waste ore samples (pH 3.0) were collected at an acid mine drainage (AMD) site in Anhui, China. The present acidophilic microbial community in the waste ore was studied with 16S rRNA gene clone library and denaturing gradient gel electrophoresis (DGGE). Eighteen different clones were identified and affiliated with Actinobacteria, low G + C Gram-positives, Thermomicrobia, Acidobacteria, Proteobacteria, candidate division TM7, and Planctomycetes. Phylogenetic analysis of 16S rRNA gene sequences revealed a diversity of acidophiles in the samples that were mostly novel. It is unexpected that the moderately thermophilic acidophiles were abundant in the acidic ecosystem and may play a great role in the generation of AMD. The result of DGGE was consistent with that of clone library analysis. These findings help in the better understanding of the generation mechanism of AMD and in developing a more efficient method to control AMD.

A sediment sample (pH 2.5) was collected at an acid mine drainage site in Anhui, China. The present acidophilic microbial community in the sediment was studied with a 16S rRNA gene clone library. Small-subunit rRNA genes were PCR amplified, cloned and screened by amplified rDNA restriction analysis (ARDRA). Subsequently, 10 different clones were identified and they were affiliated with Acidobacteria, β/γ-Proteobacteria, δ-Proteobacteria, Nitrospira, Candidate division TM7, and Low G + C Gram-positives. Phylogenetic analysis of 16S rRNA gene sequences revealed a diversity of acidophiles in the sediment that were mostly novel. Unexpectedly, 16S rRNA gene sequences affiliated with δ-Proteobacteria were found to constitute more than 60% of clone library. To our knowledge, this is the first occasion that bacteria of δ-Proteobacteria have been found dominant in the acidic habitat. Anaerobic sulfate- or metal reduction is the predominant physiological trait of bacteria of this subdivision. The high sulfate, ferric iron and the presence of bioavailable carbon in the anaerobic microenvironment may result in the dominance of bacteria of δ-Proteobacteria.

Degradation kinetics of the purified terephthalic acid (PTA) petrochemical wastewater with the functional strain Fhhh was conducted in this research. Inputting the values of the 6 kinetics parameters obtained from the test, the values of the natural parameter and the values of the standard parameters for discharging wastewater into the environmental biotechnological informatics software (Ebis), the minimum reactor volume (Vmin) required and the specific degradation rate (qA) were calculated based on the activated sludge process. The minimum value of Vmin was 1309 m3 as well as the highest value of qA was 0.0136 h-1 among the Fhhh preparations kept in three different methods. The highest value of Fhhh qA was 4 fold of that of the native bacterium YZ1, and higher than that of the data published by 4 researchers and lower than that of by 2 researchers. The results show that Fhhh has the obvious potential for the degradation of PTA wastewater.