The Integrated System of Phytodepuration of Sile River Natural Park

The water conservation topic is likely to become increasingly important and alternative water resources employment should be considered as one possible response to the challenges of fresh water demand and environmental protection; among alternative water sources, municipal wastewaters represent one of the most profitable source but in order to reuse them they need adequate and advanced depuration techniques, such as the use of Integrated System of Phytodepuration (ISP). Across a 3-year sampling period, the performances of an ISP within the Natural Park of the Sile River in the Northern Italy were evaluated, analyzing raw wastewater and final effluent characteristics according to the recommendations of European and Italian legislation. The investigated ISP represents one of the first attempts designed in Italy to improve the efficiency of an existing wastewater treatment plant, able to serve 8000 equivalent inhabitants. The results obtained during the 3 years of analysis show that the designed ISP is characterized by a general efficiency value higher than 87% for TSS removal, 79% for TN, 91% for BOD₅ and 86% for COD; moreover the ISP final effluent is characterized by a quality not only suited for release into surface waters but also for irrigation.     

Reclamation of municipal domestic wastewater by aquaponics of tomato plants

In search of low-cost eco-tech for the reclamation of municipal domestic wastewater, tomato plants (Lycopersicum esculentum) were cultivated on the floating bed of pulp-free coconut fiber over four different concentrations of wastewater (25%, 50%, 75% and 100%) and groundwater as control, in 10 L plastic bucket for two months. The study revealed that PO₄-P was removed by 58.14-74.83% with maximum removal at 50% wastewater. More than 75% removal of NO₃-N was observed in all treatments. Both COD and BOD were reclaimed highest at 100% wastewater by 61.38% and 72.03%, respectively. Ammonium-N concentration was subsided below the toxic level in all the treatments. The population of coliform bacteria (Escherichia coli) was reduced to 91.10-92.18% with maximum efficiency at 100% wastewater. Growth performance was observed relatively better at 100% wastewater. Crop production as the value addition of this technology was also recorded maximum at 100% wastewater. The bioaccumulation of Cd and Ni in tomato crop was far below the threshold level, but the bioaccumulation of Pb and Cr was above the safe level by 80 times and 660 times, respectively. The aquaponically reclaimed water can be reused in agriculture, aquaculture and industries.     

Environmental assessment of municipal wastewater discharges: a comparative study of evaluation methods

Purpose

Wastewater treatment plants produce high environmental impacts on receiving water bodies and pose economic burdens on municipalities or industrial facilities. Their overall operational costs and achieved effluent quality depend very much on the influent type, presence of priority pollutants, treatment technology and required effluent quality (for discharge or for recycle/reuse). Life cycle assessment (LCA), environmental impact quantification (EIQ) and water footprint (WF) are important instruments for sustainability assessments applied for products, production and consumption evaluations in connection with natural resources depletion and pollution threats. This study focuses on the environmental assessment of a municipal wastewater treatment plant (MWWTP) discharges by means of these three evaluation methods with the purpose to understand their (methodological) weak and strong points in capturing the impacts. Such a comparative analysis is necessary to understand how the (individual) advantages provided by each of these instruments can be complimentarily used to improve an assessment framework for various stakeholders concerned with water use cycle management (regional water operators, water management authority, public authorities, research entities, societal organizations, etc.).

Methods

The three assessment methodologies (LCA, EIQ, WF) are presented, implemented and critically analysed based on a unitary set of data concerning the MWWTP of Iasi city (a municipality of approx. 300,000 inhabitants situated in the North Eastern region of Romania), the wastewater and river water quality indicators as well as all the other relevant data being collected for the year 2012.

Results and discussion

Although the three methodologies have different principles for environmental impact quantification, the results have shown that most impacts induced to surface waters due to Iasi MWWTP effluents are given by the nutrients (nitrogen and phosphorous compounds), which could induce an eutrophication impact, and to a lesser extent by pollutants responsible for toxicity impacts (such as heavy metals).

Conclusions

Based on the results of this comparative study, a critical analysis of these three methods was realized by considering the data requirements, their development and integration status. Furthermore, the strong and weak points that are relevant for each method implementation and their subsequent use by decision-makers and Water Authorities are discussed, in the context of legislative requirements (including the Water Framework Directive), actual development of regional water operators and stakeholders' interests.

     

城市污水土地处理专家系统研究

在进行污水土地处理适宜性调查和研究基础上,应用ＴｕｒｂｏＰｒｏｌｏｇ和Ｃ程序语言建立了污水土地处理专家系统（ＬＴＥＳ）．通过测试表明,该系统能对土地处理系统的进水水质、场地适宜性、出水目标等指标进行快速准确的判断和预测,解决了污水土地处理的选址、处理工艺类型选择等问题,是科学设置污水生态工程的重要工具．     

Enteroviruses in sludge: multiyear experience with four wastewater treatment plants.

We describe our experience with the isolation of viruses from four treatment plants located in different geographic areas. Over a period of 3 years, 297 enteroviruses were isolated from 307 sludge samples. The highest frequency of viral isolation (92%), including multiple isolates from single samples, was obtained from a treatment plant serving the smallest population. Excluding the polioviruses, 22 different enterovirus serotypes were isolated. The methods used to isolate the viruses were relatively simple and included an elution procedure in which beef extract was used and a disinfection step. No concentration procedure was used. Of three cell culture systems used, the RD line of human rhabdomyosarcoma cells was by far the most useful for the isolation of echoviruses; BGM and HeLa cells were particularly useful for the isolation of group B coxsackieviruses. A seasonal effect on viral isolation rates from sludge was observed.     

Agricultural reclamation of disturbed soils in a lignite mining area using municipal and coal wastes: the humus situation at the beginning of reclamation

Soils disturbed by long-term opencast mining were treated with organic waste materials for reclamation. Humic substances were extracted from waste and soil samples and analysed using pyrolysis-gas chromatography/mass spectrometry and electrofocusing. Furthermore, analytical pyrolysis permits to study all starting materials in situ. According to structural similarities, the statistical evaluation of the pyrolysis results clearly indicates three sample groups. The first group, called compost, implies the waste materials compost and composted sewage sludge. Moreover, pyrolysis revealed that coal humic substances are predominant in brown coal sludge, pure mine soils and mine soils treated with the different organic waste materials. They constitute the second group. The sewage sludge contains a high nitrogen potential, as expected, and represents the third group. Finally, pyrolysis generally showed the specific structural characteristics of humic and fulvic acids, respectively. Electrofocusing yielded for all samples a signal pattern that is typical of humic substances. However, number and ratio of the signals differ according to the special structural features of the samples. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date.     

Reuse of effluent water from a municipal wastewater treatment plant in microalgae cultivation for biofuel production

This study assessed the usability of effluent water discharged from a secondary municipal wastewater treatment plant for mass cultivation of microalgae for biofuel production. It was observed that bacteria and protozoa in the effluent water exerted a negative impact on the growth of Chlorella sp. 227. To reduce the effect, filtration or UV-radiation were applied on the effluent water as pre-treatment methods. Of all the pretreatment options tested, the filtration (by 0.2 μm) resulted in the highest biomass and lipid productivity. To be comparable with the growth in the autoclaved effluent water, the filtration with a proper pore size filter (less than 0.45 μm) or UV-B radiation of a proper dose (over 1620 mJ cm⁻²) are proposed. These findings led us to conclude that the utilization can be realized only when bacteria and other microorganisms are greatly reduced or eliminated from the effluent prior to its use.     

城市污水处理厂活性污泥生物泡沫研究进展

城市污水处理厂运行过程中一旦发生活性污泥生物泡沫,就会影响污泥沉降和处理厂运行效能,对出水水质、作业安全和公共健康带来一系列挑战。生物泡沫是自活性污泥法诞生以来长期困扰污水处理厂运行的难题。生物泡沫的形成需要气泡、表面活性物质和疏水物质等3点基本的要素,在其中主要富集了诺卡氏型丝状细菌(Nocardioformfilamentousbacteria)和微丝菌(Candidatus Microthrix parvicella)这两种类型微生物。多种环境和运行因素包括温度、溶解氧、pH、污泥龄、特别是营养物质种类和浓度等均会对这些丝状微生物的生长产生影响。抑制丝状细菌生长的常用控制策略包括选择器、生长动力学控制、投加化学药剂以及噬菌体等方法,通过降低两类丝状细菌在生化池中的浓度以期消除生物泡沫现象。本文总结了生物泡沫的类型、成因、表征生物泡沫程度的指标、影响生物泡沫的环境因素以及常用的调控策略的原理及优缺点等,尽可能全面地介绍活性污泥生物泡沫的研究现状,并探讨未来研究方向和控制策略,期望能够为今后研究活性污泥微生物和污水处理厂运行调控提供有价值的参考。     

A comparison of municipal wastewater treatment plants for big centres of population in Galicia (Spain)

Background, Aims and Scope  

It is clear that a wastewater treatment plant brings about an enhanced quality of wastewater; however, it also implies such environmental side effects as material and energy consumption as well as involving the generation of waste. This study is maintained within the boundaries of a research project that aims at the evaluation, from an environmental perspective, of the most common technical options focused on the removal of the organic matter present in urban wastewater. In particular, the paper presents the results for four centres of population with more than 50,000 inhabitants. The differences present among the facilities on their configurations will allow their comparison and the definition of the less environmentally damaging scheme for the treatment of this type of wastewater.     

Comparison of Salmonella enterica serovar distribution and antibiotic resistance patterns in wastewater at municipal water treatment plants in two California cities

AIM: To determine Salmonella enterica serovars and antibiotic resistance (ABR) in the human waste stream. METHODS AND RESULTS: Sampling of influent wastewater at municipal treatment plants in two California cities was performed by collecting composite samples, over a 24-h period, from the treatment plants on five to six occasions. Serial water quantities were filtered and cultured with a Salmonella selective method and an oxytetracycline-supplemented Salmonella selective method. Antibiotic susceptibilities to 12 antibiotics were determined and the isolates were grouped based on ABR patterns. From 983 S. enterica isolated, 102 represented unique sampling-serovar-ABR patterns. Thirty-five different serovars were identified to be distributed over 17 different ABR patterns. The serovar distribution differed between the sampling sites, whereas there was no significant trend in levels of multiple ABR. CONCLUSIONS: Salmonella enterica was recovered with ease from small sample volumes of wastewater received by municipal water treatment plants. A large variety of serovars and ABR profiles were represented in the recovered Salmonella. SIGNIFICANCE AND IMPACT OF THE STUDY: The ease of sampling and recovery of Salmonella from municipal wastewater from treatment plants makes it a valuable sampling approach for monitoring the presence of Salmonella in the human population.     

Viral composition and context in metagenomes from biofilm and suspended growth municipal wastewater treatment plants

Wastewater treatment plants (WWTPs) contain high density and diversity of viruses which can significantly impact microbial communities in aquatic systems. While previous studies have investigated viruses in WWTP samples that have been specifically concentrated for viruses and filtered to exclude bacteria, little is known about viral communities associated with bacterial communities throughout wastewater treatment systems. Additionally, differences in viral composition between attached and suspended growth wastewater treatment bioprocesses are not well characterized. Here, shotgun metagenomics was used to analyse wastewater and biomass from transects through two full-scale WWTPs for viral composition and associations with bacterial hosts. One WWTP used a suspended growth activated sludge bioreactor and the other used a biofilm reactor (trickling filter). Myoviridae, Podoviridae and Siphoviridae were the dominant viral families throughout both WWTPs, which are all from the order Caudovirales. Beta diversity analysis of viral sequences showed that samples clustered significantly both by plant and by specific sampling location. For each WWTP, the overall bacterial community structure was significantly different than community structure of bacterial taxa associated with viral sequences. These findings highlight viral community composition in transects through different WWTPs and provide context for dsDNA viral sequences in bacterial communities from these systems.     

京津冀区域市政污水厂活性污泥种群结构的多样性及差异

【背景】活性污泥中微生物的种群结构影响着污水生物处理的高效性及稳定性,是有效保证污水处理效果的关键。【目的】研究活性污泥中细菌的群落结构组成及多样性,并分析相应菌群的主要功能,旨在更好地发挥细菌的净化作用、保持污水处理过程的稳定及提高污水的处理效率。【方法】以京津冀区域内典型市政污水厂活性污泥为研究对象,通过IlluminaMiSeq高通量测序及实时定量PCR技术,对5个污水厂活性污泥的微生物种群结构特征进行了详细解析,研究不同工艺参数下活性污泥中优势种群及脱氮菌群丰度的差异。【结果】5个污水厂活性污泥种群结构具有一定差异,其中Hengshui (HS)厂污泥的群落结构受温度的影响最大,而Shahe (SH)、Daoxianghu (DXH)、Nangong(NG)厂活性污泥群落结构则受总氮、总磷与氨氮的共同影响,氨氮对SH厂活性污泥种群结构影响最大。DXH、NG和HS厂污泥中优势菌均为Anaerolineaceae,而SH和Hejian (HJ)厂的优势菌则为Saprospiraceae与Lactobacillus。活性污泥中反硝化菌丰度最高的为HJ厂,丰度最低的为HS厂,反硝化功能基因nirS比nirK分布更为广泛。【结论】对于不同污水厂,影响其活性污泥群落结构组成的环境因素也是不同的,并且特殊的进水水质也会对污泥菌群组成和生物多样性产生影响。     

A comparative study of four systems for tertiary wastewater treatment by Scenedesmus bicellularis: New technology for immobilization

Immobilization appears to be one of the best techniques to separate physically micro-algal cells from their culture medium for the purpose of algal tertiary wastewater treatment. High operation costs and other drawbacks of large-scale physico-chemical methods of harvest led to a comparative study of biotreatment systems. Before treatment began, Scenedesmus bicellularis cells were conditioned (starved) under four different sets of conditions: 1) non-immobilized cells with air bubbling (NCA); 2) cells immobilized in alginate beads (CBW) and 3) cells immobilized on alginate screens (CSW), all conditioned in synthetic culture medium depleted in N and P; 4) cells immobilized on alginate screens but conditioned in air at 100% relative humidity (CSA). Starvation was started under a light:dark photoperiod of 16:8 h. Starved cells were then used to treat wastewater for a 2-h period. The performance of each system was evaluated by determination of residual NH₄-N and phosphate ions and by growth (dry weight, total chlorophyll, cell count, protein content). We then tested the capacity of microalgae immobilized on screens to eliminate N and P from a secondary municipal wastewater effluent and examined the influence of temperature and starvation. The quality of treated effluents was improved considerably with the system using CSA or CSW model. For CSA model, the protein content was 22.4 pg cell^-1 compared to 12.9, 9.5, 9.1 pg cell^-1 for NCA, CBW and CSW models, respectively. The CBW and CSW models were efficient for chlorophyll synthesis. The residual ammonium content in natural wastewater after 2 h of treatment with CSA model was 39% at 6±2 °C and reached 100% removal at 18±2 °C. With the first 2 h, the removal of orthophosphate was inferior (53%) at 6±2 °C, but 88 to 100% at 18±2 °C depending on starvation times. Long starvation times (72 or 96 h) caused damage to cells and uptake of nutrients was lower than with 54 h starvation. This work demonstrates that by using immobilization on screens, removal of nutrients from wastewater was higher than with conventional biological tertiary wastewater treatments (free cells or bead-shaped alginate particles).     

Critical evaluation of municipal solid waste composting and potential compost markets

Mechanical biological treatment (MBT) of mixed waste streams is becoming increasingly popular as a method for treating municipal solid waste (MSW). Whilst this process can separate many recyclates from mixed waste, the resultant organic residue can contain high levels of heavy metals and physical and biological contaminants. This review assesses the potential end uses and sustainable markets for this organic residue. Critical evaluation reveals that the best option for using this organic resource is in land remediation and restoration schemes. For example, application of MSW-derived composts at acidic heavy metal contaminated sites has ameliorated soil pollution with minimal risk. We conclude that although MSW-derived composts are of low value, they still represent a valuable resource particularly for use in post-industrial environments. A holistic view should be taken when regulating the use of such composts, taking into account the specific situation of application and the environmental pitfalls of alternative disposal routes.     

Microbial community analysis of three municipal wastewater treatment plants in winter and spring using culture-dependent and culture-independent methods

Low temperatures can result in start-up and operational problems in wastewater treatment plants. The microbial community structures of three full-scale biological processes for municipal wastewater treatment, namely, anoxic-oxic activated sludge (A/O) process, oxidation ditch, and sequencing batch reactor, in winter and spring were investigated. The performances of the three biological processes were all stable during winter and spring. Comparing all three plants, the NH(4) (+)-N removal efficiency using the A/O process was found to be the highest during both winter and spring. According to the similarity coefficient of the polymerase chain reaction and denaturing gradient gel electrophoresis analysis determined via the culture-independent method, the microbial community structure is the most stable using the A/O process at different temperatures. The dominant members primarily belonged to Proteobacteria, Nitrospira, and Bacteroidetes. In addition, Proteobacteria was the dominant member in the activated sludge utilizing peptone, glucose, and fatty acid. Compared with other biological processes, the A/O process was superior at low temperatures based on its pollution removal performance and stable microbial community sturcture.     

Abundance and population structure of ammonia-oxidizing bacteria that inhabit canal sediments receiving effluents from municipal wastewater treatment plants

A polyphasic, culture-independent study was conducted to investigate the abundance and population structure of ammonia-oxidizing bacteria (AOB) in canal sediments receiving wastewater discharge. The abundance of AOB ranged from 0.2 to 1.9% and 1.6 to 5.7% of the total bacterial fraction by real-time PCR and immunofluorescence staining, respectively. Clone analysis and restriction endonuclease analysis revealed that the AOB communities influenced by the wastewater discharge were dominated by Nitrosomonas, were similar to each other, and were less diverse than the communities outside of the immediate discharge zone.     

城市供水系统摇蚊污染发生与防治研究

近年来 ,国内已有 1 0余个省区城市供水系统中先后发生了摇蚊幼虫 (红虫 )污染事件。文章介绍了国内外供水系统摇蚊发生概况 ;分析了供水系统中摇蚊发生的 3个主要原因 :原水环境污染 ,水处理过程摇蚊污染和二次供水污染。简要回顾了国外供水系统摇蚊污染防除的历史和进展 ;重点介绍了目前国内供水行业所采用物理、化学以及生物的方法在水厂净水处理及二次供水过程防除摇蚊污染的研究 ;同时指出了当前有关研究和实践中存在的主要问题是对摇蚊生物学和生态学等知识的缺乏。对该问题开展进一步研究提出了建议     

4种沉水植物对富营养化水体氮磷的去除能力

沉水植物常用于水质净化与生态修复工程.本实验通过室内模拟与测定,分析比较4种常见沉水植物在6个种植密度梯度(0.5g·L^-1～3g·L^-1)下对世博后滩公园生态水系氮、磷污染物的去除率.30d模拟实验结果表明,4种沉水植物对水体中过量氮、磷均有较高的去除率,在种植密度为3g·L^-1时,轮叶黑藻(HydriHa verticillata)对TN去除率最高达到6%,马来眼子菜(Potamogeton malaianus)对TP的去除率最高为88%.在种植密度为0.5g·L^-1～3g·L^-1的范围内时,各沉水植物实验组随种植密度的增大,对氮、磷的去除率升高.     

Genotoxicity biomonitoring of sewage in two municipal wastewater treatment plants using the Tradescantia pallida var. purpurea bioassay

The genotoxicity of untreated and treated sewage from two municipal wastewater treatment plants (WTP BN and WTP SJN) in the municipality of Porto Alegre, in the southern Brazilian state of Rio Grande do Sul, was evaluated over a one-year period using the Tradescantia pallida var. purpurea (Trad-MCN) bioassay. Inflorescences of T. pallida var. purpurea were exposed to sewage samples in February (summer), April (autumn), July (winter) and October (spring) 2009, and the micronuclei (MCN) frequencies were estimated in each period. The high genotoxicity of untreated sewage from WTP BN in February and April was not observed in treated sewage, indicating the efficiency of treatment at this WTP. However, untreated and treated sewage samples from WTP SJN had high MCN frequencies, except in October, when rainfall may have been responsible for reducing these frequencies at both WTPs. Physicochemical analyses of sewage from both WTPs indicated elevated concentrations of organic matter that were higher at WTP SJN than at WTP BN. Chromium was detected in untreated and treated sewage from WTP SJN, but not in treated sewage from WTP BN. Lead was found in all untreated sewage samples from WTP SJN, but only in the summer and autumn at WTP BN. These results indicate that the short-term Trad-MCN genotoxicity assay may be useful for regular monitoring of municipal WTPs.