Do Contaminants Originating from State-of-the-Art Treated Wastewater Impact the Ecological Quality of Surface Waters?

Since the 1980s, advances in wastewater treatment technology have led to considerably improved surface water quality in the urban areas of many high income countries. However, trace concentrations of organic wastewater-associated contaminants may still pose a key environmental hazard impairing the ecological quality of surface waters. To identify key impact factors, we analyzed the effects of a wide range of anthropogenic and environmental variables on the aquatic macroinvertebrate community. We assessed ecological water quality at 26 sampling sites in four urban German lowland river systems with a 0–100% load of state-of-the-art biological activated sludge treated wastewater. The chemical analysis suite comprised 12 organic contaminants (five phosphor organic flame retardants, two musk fragrances, bisphenol A, nonylphenol, octylphenol, diethyltoluamide, terbutryn), 16 polycyclic aromatic hydrocarbons, and 12 heavy metals. Non-metric multidimensional scaling identified organic contaminants that are mainly wastewater-associated (i.e., phosphor organic flame retardants, musk fragrances, and diethyltoluamide) as a major impact variable on macroinvertebrate species composition. The structural degradation of streams was also identified as a significant factor. Multiple linear regression models revealed a significant impact of organic contaminants on invertebrate populations, in particular on Ephemeroptera, Plecoptera, and Trichoptera species. Spearman rank correlation analyses confirmed wastewater-associated organic contaminants as the most significant variable negatively impacting the biodiversity of sensitive macroinvertebrate species. In addition to increased aquatic pollution with organic contaminants, a greater wastewater fraction was accompanied by a slight decrease in oxygen concentration and an increase in salinity. This study highlights the importance of reducing the wastewater-associated impact on surface waters. For aquatic ecosystems in urban areas this would lead to: (i) improvement of the ecological integrity, (ii) reduction of biodiversity loss, and (iii) faster achievement of objectives of legislative requirements, e.g., the European Water Framework Directive.     

Sorption of hydrophobic organic contaminants and trace metals on phytoplankton and implications for toxicity assessment

The partitioning of trace metals and hydrophobic organic contaminants to phytoplankton determines their toxicity as well as their fate and transport in aquatic ecosystems. Accurate impact assessments, therefore, depend on a good understanding of the factors regulating the sorption of these compounds to biotic particles. The accumulation of chlorinated organic compounds in phytoplankton is generally considered as being due solely to physical sorption, described by reversible equilibrium models based on Langmuir or Freundlich isotherms. On the other hand, the uptake of trace metals is a two phase process: a fast sorption component viewed as an ionexchange or a covalent bonding process with cell surface ligands, followed by an intracellular transport phase that is dependent on cellular metabolic activity. The uptake of inorganic and hydrophobic organic pollutants and their bioaccumulation are influenced in a complex manner by duration of exposure and cell density, by environmental factors such as pH, the concentration of cations and of dissolved and colloidal organic matter, as well as by phytoplankton physiological condition. High concentrations of H⁺, Ca²⁺, and Mg²⁺ ions will reduce trace metal sorption by directly competing for uptake sites on the cell's surface, whereas the presence of dissolved organic carbon such as natural and synthetic chelators and phytoplankton exudates will reduce the bioavailability of both trace metals and hydrophobic organic contaminants. Thus, the impact of toxic contaminants on phytoplankton may be determined as much by the factors influencing uptake and partitioning as by the potency of the toxicants and interspecies differences in sensitivity. Recommendations for improving toxicity assessments are presented.     

A novel magnetic biochar efficiently sorbs organic pollutants and phosphate

Biochar derived from agricultural biomass waste is increasingly recognized as a multifunctional material for agricultural and environmental applications. Three novel magnetic biochars (MOP250, MOP400, MOP700) were prepared by chemical co-precipitation of Fe³⁺/Fe²⁺ on orange peel powder and subsequently pyrolyzing under different temperatures (250, 400 and 700 °C), which resulted in iron oxide magnetite formation and biochar preparation in one-step. The MOP400 was comprised of nano-size magnetite particles and amorphous biochar, and thus exhibited hybrid sorption capability to efficiently remove organic pollutants and phosphate from water. For organic pollutants, MOP400 demonstrated the highest sorption capability, and even much larger than the companion non-magnetic biochar (OP400). For phosphate, magnetic biochars, especially MOP250, demonstrated much higher sorption capability than the companion non-magnetic biochars. No significantly competitive effect between organic pollutant and phosphate was observed. These suggest that the magnetic biochar is a potential sorbent to remove organic contaminants and phosphate simultaneously from wastewater.     

An analysis of the bacterial community in a membrane bioreactor fed with photo-Fenton pre-treated toxic water

A photo-Fenton-membrane bioreactor (MBR) coupled system is an innovative tool for the treatment of wastewater containing high quantities of contaminants. In this paper, wastewater with 200 mg l^?1 of dissolved organic carbon (DOC) of a selected mixture of five commercial pesticides: Vydate^®, Metomur^®, Couraze^®, Ditimur-40^®, and Scala^® was treated by combining photo-Fenton and MBR. The effect of photo-treated pollutants on MBR operation was investigated by studying the population changes that occurred with time in the activated sludge of the biological system. Pre-treatment with photo-Fenton was carried out (only up to 34% of mineralization of DOC) and, after MBR treatment, 98% of biodegradation efficiency was obtained. During the biological treatment, little changes in the activated sludge population were detected by DGGE analysis, maintaining acceptable biodegradation efficiency, which points out the robustness of the MBR treatment versus changes in feed composition.     

Evaluation of “Classic” and Emerging Contaminants Resulting from the Application of Biosolids to Agricultural Lands: A Review

The presence of detectable amounts of contaminants in treated sewage sludge (concentrations μg/kg – mg/kg) has led to concerns that land applications of biosolids may result in an accumulation of contaminants in the soil and their subsequent translocation through the food chain. Despite advances in wastewater management (e.g., anaerobic, thermophilic, and mesophilic digestion), many compounds and their metabolites remain intact following treatment. This review looks at the main risk factors relating to the occurrence of “classic” (persistent organic pollutants [POPs]) and emerging pollutants (pharmaceuticals and personal care products) in biosolids. Relevant EU legislation and risk assessment strategies for the control of emerging contaminants are also considered. Organic pollutants regulated under the Stockholm Convention on POPs along with PPCPs were identified as contaminants of concern based on the risk factors: persistence, bioaccumulation, and toxicity (PBT). PPCPs were recognized as being of particular concern as their high transformation/removal rates are compensated by their continuous introduction into the environment. This study highlights the growing concern in relation to emerging contaminants in biosolids and highlights risk assessment strategies that can be used to characterize potential human/environmental risks.     

Cobalt sorption onto anaerobic granular sludge: isotherm and spatial localization analysis

This study investigated the effect of different feeding regimes on the cobalt sorption capacity of anaerobic granular sludge from a full-scale bioreactor treating paper mill wastewater. Adsorption experiments were done with non-fed granules in monometal (only Co) and competitive conditions (Co and Ni in equimolar concentrations). In order to modify the extracellular polymeric substances and sulfides content of the granules, the sludge was fed for 30 days with glucose (pH 7, 30 degrees C, organic loading rate=1.2 g glucose l(-1) day-1) in the presence (COD/SO4(2-)=1) or absence of sulfate. The partitioning of the sorbed cobalt between the exchangeable, carbonates, organic matter/sulfides and residual fractions was determined using a sequential extraction procedure (modified Tessier). Experimental equilibrium sorption data for cobalt were analysed by the Langmuir, Freundlich and Redlich-Peterson isotherm equations. The total Langmuir maximal sorption capacity of the sludge fed with glucose and sulfate loaded with cobalt alone displayed a significantly higher maximal cobalt sorption (Qmax =18.76 mg g-1 TSS) than the sludge fed with glucose alone (Qmax =13.21 mg g-1 TSS), essentially due to an increased sorption capacity of the exchangeable (30-107%) and organic/sulfides fractions (70-30%). Environmental scanning electron microscopy coupled with an energy dispersive X-ray analysis of granular cross-sections showed that mainly iron minerals (i.e. iron sulfides) were involved in the cobalt accumulation. Moreover, the sorbed cobalt was mainly located at the edge of the granules. The sorption characteristics of the exchangeable and carbonates fractions fitted well to the Redlich-Peterson model (intermediate multi-layer sorption behaviour), whereas the sorption characteristics of the organic matter/sulfides and residual fractions fitted well to the Langmuir model (monolayer sorption behaviour). The organic matter/sulfides fraction displayed the highest affinity for cobalt for the three sludge types investigated.     

再生(污)水灌溉生态风险与可持续利用

作为一个农业大国,水资源贫乏及地域分布不均匀造成了我国严重的农业用水危机。为缓解我国农业用水危机,污水灌溉及再生水灌溉已成为解决农业灌溉水源不足的一项重要措施。在总结污水灌溉及再生水灌溉生态风险的基础上,针对国内研究现状,分析了我国再生水灌溉利用的可行性。研究发现,再生水灌溉的污染风险远小于污水灌溉,且再生水灌溉还具有回用成本低、减少农作物生产成本等经济效益,以及减少污染物向水环境中排放、改善土壤质量等环境效益。与污水灌溉相比再生水在农业灌溉上具有较大的应用前景,应加大其推广与应用的力度。最后,根据国内外的研究现状,提出了一些再生水灌溉可持续管理措施及其安全利用的相关建议。     

Effects of plants and microorganisms in constructed wetlands for wastewater treatment

Constructed wetlands are a natural alternative to technical methods of wastewater treatment. However, our understanding of the complex processes caused by the plants, microorganisms, soil matrix and substances in the wastewater, and how they all interact with each other, is still rather incomplete. In this article, a closer look will be taken at the mechanisms of both plants in constructed wetlands and the microorganisms in the root zone which come into play when they remove contaminants from wastewater. The supply of oxygen plays a crucial role in the activity and type of metabolism performed by microorganisms in the root zone. Plants' involvement in the input of oxygen into the root zone, in the uptake of nutrients and in the direct degradation of pollutants as well as the role of microorganisms are all examined in more detail. The ways in which these processes act to treat wastewater are dealt with in the following order: Technological aspects; The effect of root growth on the soil matrix; Gas transport in helophytes and the release of oxygen into the rhizosphere; The uptake of inorganic compounds by plants; The uptake of organic pollutants by plants and their metabolism; The release of carbon compounds by plants; Factors affecting the elimination of pathogenic germs.     

沙蚕耐污染的特征及机理研究进展

沙蚕（Nereis diversicolor）是一种栖息于海陆交错带、具有重要生态学意义的无脊椎动物.近年来发现,沙蚕体内能够蓄积大量的重金属等有毒有害污染物,且表现出较强的污染耐性.文中就沙蚕对重金属和有机污染物具有的污染耐性特征和最新国内外研究进展进行了概述,并就其污染耐性形成的机理进行了分析.沙蚕的污染耐性机制可能是通过多种生态化学过程实现的,包括通过大量粘液的分泌,在沙蚕体表形成一层保护膜;与有效态以及溶解于水中的污染物离子结合,从而降低污染物的生物可利用性;加快排泄速率等.更多的研究认为,沙蚕将吸收进入体内的重金属等有毒有害污染物以无毒的形式存贮,达到解毒的目的.这些无毒形式主要包括:与金属结合蛋白MTs和MTLP的结合物,热稳定硫醇化合物（CHSTC）,或者与重金属相互结合形成不溶性的溶酶体/微粒和结石等颗粒物或沉淀物.最后,对沙蚕生态毒理学研究以及耐性机制研究的工作重点进行了展望.     

Characterisation of dissolved organic matter in Parisian urban aquatic systems: predominance of hydrophilic and proteinaceous structures

Understanding the nature of organic matter is a necessary first step in assessing contaminant bioavailability and allowing water supply managers to optimise the treatment train in the aim of providing safe and inexpensive drinking water. This study provides further insight into the composition, structure and functional groups of dissolved organic matter (DOM) (both hydrophobic and hydrophilic) from urban aquatic systems by means of various analytical techniques (DAX-8/XAD-4 fractionation, elemental analysis, UV and FTIR spectroscopies, ¹³C and ¹⁵N isotopic analysis, size exclusion chromatography and Pyrolysis-GC-MS). The analytical range chosen for this study constitutes a powerful tool in the characterisation of DOM in urban water. The inclusion of information from one technique to the next might not only serve as a support to each one, but also as a complement. The DOM fraction from treated effluent and, more generally, DOM from urban water (i.e. receiving treated effluent) display a strong hydrophilic characteristic [i.e. low humic substance (HS) content, low SUVA], along with a high distribution in molecular weights observed by SEC and low average molecular weight. Due to the origin of this DOM, proteinaceous structures constitute the main compounds, as observed by FTIR and Py-GC-MS. Such characteristics (i.e. heterogeneity, low average molecular weight and diverse functional groups, which make up a total of N) could explain that DOM from treated effluent displayed a strong reactive potential metals pollutants as previously demonstrated.     

Current research trends on microplastic pollution from wastewater systems: a critical review

Microplastics have been widely considered as contaminants for the environment and biota. Till now, most previous studies have focused on the identification and characterization of microplastics in freshwater, sea water, and the terrestrial environment. Although microplastics have been extensively detected in the wastewater, research in this area is still lacking and not thoroughly understood. To fill this knowledge gap, the current review article covers the analytical methods of microplastics originating from wastewater streams and describes their sources and occurrences in wastewater treatment plants (WWTPs). Studies indicated that microplastic pollution caused by domestic washing of synthetic fibers could be detected in the effluent; however, most microplastics from personal care and cosmetic products (PCCPs) can be efficiently removed during wastewater treatment. Moreover, various techniques for sampling and analyzing microplastics from wastewater systems are reviewed; while, the implementation of standardized protocols for microplastics is required. Finally, the fate of microplastics during wastewater treatments and the environmental contamination of effluent to environment are presented. Previous studies reported that the advanced wastewater treatment (e.g., membrane bioreactor) is needed for improving the removal efficiency of small-sized microplastics (<?100 µm). Although the role of microplastics as transport vectors for persistent organic pollutants (POPs) is still under debate, they have demonstrated abilities to absorb harmful agents like pharmaceuticals.

     

Bacterial diversity, organic pollutants and their metabolites in two aeration lagoons of common effluent treatment plant (CETP) during the degradation and detoxification of tannery wastewater

In this study, PCR-RFLP and GC-MS approaches were used to characterize the bacterial diversity, organic pollutants and metabolites during the tannery wastewater treatment process at common effluent treatment plant (CETP). Results revealed that the bacterial communities growing in aeration lagoon-I were dominated with Escherichia sp., Stenotrophomonas sp., Bacillus sp. and Cronobacter sp. while that of aeration lagoon-II prevailed with Stenotrophomonas sp., and Burkholderiales bacterium, respectively. The HPLC and GC-MS analysis revealed that most of the organic pollutants detected in untreated tannery wastewater samples were diminished from bacterial treated tannery wastewater samples. Only two pollutants i.e. L-(+)-lactic acid and acetic acid could not be degraded by bacteria whereas benzene and 2-hydroxy-3-methyl-butanoic acid was produced as new metabolites during the bacterial treatment of tannery wastewater in aeration lagoon II of CETP. Further, it was observed that after bacterial treatment, the toxicity of tannery effluent was reduced significantly allowing 90% seed germination.     

Application of zero valent iron coupling with biological process for wastewater treatment: a review

As a promising technology, zero valent iron (ZVI) coupling with microorganisms has attracted extensive attention for contaminants removal from wastewater. The current paper provides a comprehensive review on recent developments in: (1) the chemical behavior of ZVI and potential mechanisms of integrated bio-ZVI technology in contaminants removal; (2) synergistic effects of bio-ZVI towards various common environmental pollutants in wastewater, including inorganic oxyanions, organic compounds, heavy metals and dyes; (3) promotion effects of ZVI on the biologically anaerobic digestion of waste sludge; (4) operating factors affecting the effectiveness of bio-ZVI process; (5) measures developed to enhance the long-term performance of the bio-ZVI technology. The chemical behavior and stimulating roles of ZVI playing in the growth and diversity of microorganisms is reasonable for the synergistic effects of the combined system. It was demonstrated that combined bio-ZVI system showed appreciable removal efficiencies for several types of contaminants. Additionally, the formation of passive layer on the ZVI surface can be avoided by the means of electrochemical and microbial method. Lastly, this review highlighted the research gaps to improve the sustainability of this technology. Based on these understandings, further efforts should be made to expand the applications of this combined technology and establish some feasible strategies to provide opportunities for the engineering applications.     

Organic matter,anion, and metal wastewater treatment in Damyang surface-flow constructed wetlands in Korea

Surface-flow wetlands constructed with Acorus and Typha plants, connected to a wastewater treatment plant, were investigated with respect to organics (dissolved organic matter), anions (nitrate, sulfate, and phosphate), metals (Cu, Ni, Zn, Fe, and Mn), and metalloids (As). The results of the research indicated: (1) effluent organic matter (EfOM), based on dissolved organic carbon (DOC), was not efficiently removed by the wetlands. However, the hydrophobic, transphilic, and hydrophilic EfOM fractions varied throughout the wetlands, as identified by XAD-8/4 resins. (2) Nitrate, as compared to sulfate and phosphate, was efficiently removed, especially in the Typha wetland pond that had long retention time, under anoxic condition. (3) Most of the heavy metals were ineffectively removed via the wetland ponds. However, the iron concentration increased in the Typha wetland pond, which was probably due to its reduction under anoxic condition.     

Anaerobic fluidised bed for the purification of effluents from chemical and mechanical pulping

Anaerobic treatment has seldom been used for wastewaters from the pulp and paper industry and other branches of the chemical industry. Escape of volatile pollutants to the atmosphere, which always occurs during aerobic treatment, is avoided, and much less sludge is being produced than in an aerobic process. The greatest obstacle for using anaerobic treatment in the pulp and paper industry is the large wastewater volume, which necessitates short hydraulic detention times, because the treatment is to occur in an enclosed space. We used solid carrier particles to prevent wash-out of biomass from the reactor at high hydraulic loading, and an up-flow system in order to be able to use very small carrier particles, maximizing the surface area for biomass attachment. In this paper we describe and discuss the results obtained with this type of anaerobic reactor (fluidised bed) at bench and semitechnical scale for wastewaters from pressurized ground wood pulping and paper manufacture, sulphite pulp evaporator condensate and bleach waste. Earlier work with Kraft pulp bleaching effluent and thermomechanical pulping wastewater and evaporator condensates using anaerobic reactors is also discussed. The results obtained thus far show that there are several wastewater streams from the pulping industry, where 60 to 90% of the dissolved organic pollutants (measured as COD_Cr or TOC) was biodegraded within 4 to 24 h. The high strength waste streams (COD_Cr 2000 mg O₂ 1⁻¹) allowed organic space load of 4 to 10 kg COD_Cr m⁻³ reactor volume d⁻¹. With low strength wastes the hydraulic loading was the limiting factor.     

Effect of yeast extract on speciation and bioavailability of nickel and cobalt in anaerobic bioreactors

The speciation of metals plays an important role in their bioavailability. In the case of anaerobic reactors for the treatment of wastewaters, the ubiquitous presence of sulfide leads to extensive precipitation of metals like nickel and cobalt, which are essential for the metabolism of the anaerobic microorganisms that carry out the mineralization of the pollutants present in the wastewater. In practice, nickel, cobalt, and iron are added in excessive amounts to full-scale installations. This study is concerned with the complexation of nickel and cobalt with yeast extract and its effect on the biogas production by methanogenic biomass. Adsorptive stripping voltammetry (AdSV) was used to get information about the stability and complexing capacity of the metal-yeast extract complexes formed. Nickel and cobalt form relatively strong organic complexes with yeast extract. The bioavailability of these essential metals in anaerobic batch reactors was dramatically increased by the addition of yeast extract. This is due to the formation of dissolved bioavailable complexes, which favors the dissolution of metals from their sulfides. Trace doses of yeast extract may be effective in keeping additions of essential metals to anaerobic reactors at a minimum.     

Release of treated effluent into streams: A global review of ecological impacts with a consideration of its potential use for environmental flows

1. Worldwide, the addition of treated wastewater (i.e. effluent) to streams is becoming more common as urban populations grow and developing countries increase their use of wastewater treatment plants. Release of treated effluent can impair water quality and ecological communities, but also could help restore flow and maintain aquatic habitat in water-stressed regions. To assess this range of potential outcomes, we conducted a global review of studies from effluent-fed streams to examine the impacts of effluent on water quality and aquatic and riparian biota.
2. We identified 147 quantitative studies of effluent-fed streams, most of which were from the U.S.A. and Europe. Over 85% of the studies identified water quality as a primary study focus, including basic physical and chemical parameters, as well as trace organic contaminants. Nearly 60% of the studies had at least some focus on aquatic or riparian biota, primarily fish, aquatic invertebrates, and basal resources (e.g. algae).
3. Effluent inputs generally impaired water quality near discharge points, mainly through increased water temperature, nutrients, and concentrations of trace organic contaminants, but also via decreased dissolved oxygen levels. The majority of ecological studies found that basal resources, aquatic invertebrates, and fish were negatively affected in a variety of ways (e.g. biodiversity losses, replacement of sensitive with tolerant species). However, several studies showed the importance of effluent in providing environmental flows to streams that had been dewatered by anthropogenic water withdrawals, especially in semi-arid and arid regions.
4. Knowledge gaps identified include the abiotic impacts of effluent, such as changes in channel morphology and hydrology (e.g. how nutrient-rich and warmer effluent affects infiltration rates or interactions with groundwater), the effects of effluent on plants and vertebrates (e.g. amphibians, birds), and the impact of effluent-induced perennialisation on naturally intermittent or ephemeral streams.
5. Although effluent-fed streams often exhibit signs of ecological impairment, there is great potential for these systems to serve as refuges of aquatic biodiversity and corridors of ecological connectivity when wastewater treatment standards are high, especially in semi-arid and arid regions where natural streams have been dewatered.

     

落叶松林土壤可溶性碳、氮和官能团特征的时空变化及与土壤理化性质的关系

土壤可溶性有机碳(DOC)、可溶性有机氮(DON)及其官能团特征在土壤碳、氮循环中作用非常重要。对25个不同年龄落叶松林样地、4个深度(0-20、20-40、40-60和60-80 cm)土壤DOC、DON、有机物官能团(芳香性、分子量和疏水性)特征指标(254、260、272 nm和280 nm的单位吸光度值SUVA:吸光度值/DOC含量)和土壤理化指标(土壤全碳SOC、全氮SON、pH值、电导率、容重)进行测定,旨在探究它们的时、空变化特征及与土壤理化指标相关关系。在空间尺度上,与SOC、SON一致,表层土壤DOC、DON多显著高于深层(P<0.05),但是4个单位吸光度值SUVA₂₅₄、SUVA₂₆₀、SUVA₂₇₂和 SUVA₂₈₀均不存在差异(P>0.05);在时间尺度上,仅表层土壤DOC、SOC 和SON随落叶松年龄显著线性增长(P<0.05),而深层DOC、SOC、SON、不同层土壤DON及各官能团指标均没有显著变化(P>0.05)。可见,土壤可溶性有机物内碳的累积(7 mg kg^-1 a^-1)是SOC累积的一部分(762 mg kg^-1 a^-1),但其DON及可溶性有机物芳香性比例、分子量大小及疏水性容量等官能团特征并未受落叶松生长时间以及土壤深度的显著影响。进一步回归分析表明这些官能团指标随土壤DOC含量增加而指数下降,深层土壤同时受DON显著影响。表层土壤DOC、DON与土壤SOC、SON、土壤电导率显著正相关(P<0.05),深层相关不显著(P>0.05),而官能团指标与土壤理化性质的相关性在各个土层均不显著,显示出表层土壤可溶性有机物的量,而不是官能团组成对土壤理化性质影响显著,而深层土壤可溶性有机物量对土壤理化性质不构成显著影响。对于从可溶性组分、官能团角度,分析落叶松人工林成长过程中土壤碳、氮时空变化具有科学意义。     

合成生物学在环境修复中的应用

环境问题是21世纪人类面临的最严重的挑战。随着现代工农业飞速发展,生态环境日益恶化,难降解污染物如新兴污染物逐渐显现,已成为制约社会经济可持续发展的重要因素。微生物具有强大的环境修复能力,但是其进化速度远不及新兴污染物出现的速度,亟需应用合成生物学的技术来解决这一难题。在充分认识难降解有机污染物微生物降解(途径)特性的基础上,利用我国丰富的微生物与基因资源,运用合成生物学的手段,定向设计和改造现有降解菌株,构建能够降解一种或多种污染物的工程菌株;同时针对复合型污染,如废水等,在建立典型有机污染物代谢、调控和抗逆相关基因元件的模块库基础上,引入人工菌群等策略,对生物系统进行理性设计和组装,构建典型环境污染物的高效降解菌群,可有效促进我国新兴污染物微生物分解代谢的研究,为环境修复的工程应用提供技术支持。     

Sphaerotilus natans,a Neutrophilic Iron-Related Sheath-Forming Bacterium: Perspectives for Metal Remediation Strategies

Sphaerotilus natans is a neutrophilic sheath-forming microorganism from the Sphaerotilus-Leptothrix group of iron-related bacteria, known to form bacteriogenic iron oxides (BIOS) frequently deposited on cell surfaces as well as on sheaths and extracellular polymeric substances. S. natans has been reported to be an excellent sorbent for inorganic pollutants, either due to direct sorption onto biological surfaces or due to sorption onto BIOS. However, its filaments can cause bulking problems in wastewater treatment plants. This article promotes the potential applications of Sphaerotilus natans in bioremediation by reviewing its physiology and the fundamental understanding of sheath-forming mechanisms as well as iron biomineralization processes.