A New Perspective on Sustainable Soil Remediation—Case Study Suggests Novel Fungal Genera Could Facilitate in situ Biodegradation of Hazardous Contaminants

Deciding upon a cost effective and sustainable method to address soil pollution is a challenge for many remedial project managers. High pressure to quickly achieve cleanup goals pushes for energy‐intensive remedies that rapidly address the contaminants of concern with established technologies, often leaving little room for research and development especially for slower treatment technologies, such as bioremediation, for the more heavily polluted sites. In this case study, new genomic approaches have been leveraged to assess fungal biostimulation potential in soils polluted with particularly persistent hydrophobic contaminants. This new approach provides insights into the genetic functions available at a given site in a way never before possible. In particular, this article presents a case study where next‐generation sequencing has been used to categorize fungi in soils from the Atlantic Wood Industries Superfund site in Portsmouth, Virginia. Data suggest that original attempts to harness fungi for bioremediation may have focused on fungal genera poorly suited to survive under heavily polluted site conditions, and that more targeted approaches relying on native indigenous fungi which are better equipped to survive under site‐specific conditions may be more appropriate. ©2016 Wiley Periodicals, Inc.     

Successful genetic bioaugmentation with Pseudomonas putida for toluene degradation in soil columns

There is a strong need for effective and sustainable treatment methods for remediating soils and waters contaminated by fossil fuel pollutants such as aromatic hydrocarbons. Remediation could be improved by genetic bioaugmentation that uses conjugation of catabolic plasmids between bacteria. Research on the conditions for success, effectiveness, and long-term impact of genetic bioaugmentation are therefore necessary. Here the effects of genetic bioaugmentation with Pseudomonas putida BBC 443 was studied in continuous-flow soil columns with or without glucose amendment. Results show that the highest transconjugant occurrence of 21.7 ± 2.1 %, and development of microbial communities with the highest overall toluene degradation potential of 0.0790 ± 0.0055 mg toluene/g soil/h, were achieved in soil columns that received a continuous addition of 1 g/L glucose. Plasmid transfer and toluene biodegradation did not depend on the survival of donor P. putida BBC443, suggesting that genetic bioaugmentation was successful. Furthermore, bacterial community structure analysis revealed that genetic bioaugmentation had limited long-term impact on the soil bacterial community structures, regardless of the specific treatment. Our findings show that genetic bioaugmentation was successful and resulted in limited long-term ecological impact, thus demonstrating that genetic bioaugmentation can provide an effective and sustainable method for in situ bioremediation.     

Impacts of organic carbon availability and recipient bacteria characteristics on the potential for TOL plasmid genetic bioaugmentation in soil slurries

The effectiveness of genetic bioaugmentation relies on efficient plasmid transfer between donor and recipient cells as well as the plasmid’s phenotype in the recipient cell. In the present study, the effects of varying organic carbon substrates, initial recipient-to-donor cell density ratios, and mixtures of known recipient bacterial strains on the conjugation and function of a TOL plasmid were tested in sterile soil slurry batch reactors. The presence of soil organic carbon was sufficient in ensuring TOL plasmid transconjugant occurrence (up to 2.1 ± 0.5%) for most recipient strains in soil slurry batch mating experiments. The addition of glucose had limited effects on transconjugant occurrence; however, glucose amendment increased the specific toluene degradation rates of some Enterobacteriaceae transconjugants in soil slurry. Initial cell density ratios and mixtures of recipient strains had smaller impacts on plasmid conjugation and resulting phenotype functionality. These observations suggest that genetic bioaugmentation may be improved by minimal altering of environmental conditions.     

Effects of selected pharmaceutically active compounds on the ammonia oxidizing bacterium Nitrosomonas europaea

Pharmaceutically active compounds (PhACs) are commonly found in wastewater influent. However, little research has focused on determining their impact on fundamental processes in wastewater treatment such as nitrogen removal. In this study, focus was placed on 4 commonly occurring PhACs (ketoprofen, naproxen, carbamazepine and gemfibrozil). Their effect was ascertained in the ammonia oxidizing bacterium (AOB), Nitrosomonaseuropaea in terms of membrane integrity and nitrite production. These PhACs were shown to inhibit nitrite production at concentrations of 1 and 10 μM while no effect was observed at 0.1 μM. The maximum observed nitrification inhibition was 25%, 29%, 22% and 26% for ketoprofen, naproxen, carbamazepine and gemfibrozil, respectively. A decrease in the live/dead ratio ranging from 10% to 16% suggests that these PhACs affect membrane integrity in N.europaea. The difference in nitrite production between PhACs treated cells and non PhAC treated controls was still significant following washing suggesting that inhibition is irreversible. Finally, nitrite production when adjusted to the live fraction of cells was also found to decrease suggesting that PhACs inhibited the activity of surviving cells. These results suggest that the presence of PhACs may affect AOB activity and may impact nitrogen removal, a key function in wastewater treatment. Follow up studies with additional AOB and in mixed culture are needed to further confirm these results.     

德国城镇水事管理法律的发展——供水保障和污水处理

关于饮用水供应和污水处理的法律规范,属于市政水管理的核心领域,是水管理法的重要组成部分。特别在国际和欧盟层面,以长期保障饮用水供应为核心内容的“涉水人权”成为关注热点。首先对德国水事管理法律的发展做一概览,《水法》确保一种公法上的监管秩序。尽管受到欧盟《水框架指令》影响,德国水事管理在向水环境质量达标转型,但饮用水供应与污水处理仍是《水法》的核心内容。在欧盟层面上,除了《水框架指令》外,《市政污水指令》和《饮用水指令》分别对供水保障和污水处理2个领域做了具体规定。在德国法律层面上,首先对供水保障和污水处理领域的组织体系,从集中式和分散式的发展趋势以及保障效率的私营化趋势加以评析;其次对《水法》在联邦制改革下的发展和作为水事监管核心的许可制度进行介绍;然后在污水监管领域,分别就污水排放许可的先进技术水准、直接与间接排放、污水收费和污泥处理进行分析;最后就饮用水供应领域,从水源地保护和饮用水供应2个方面加以介绍,指出了德国在水事监管领域的挑战。