Simultaneous treatment of municipal wastewater and biodiesel production by cultivation of Chlorella vulgaris with indigenous wastewater bacteria

This study examined the use of Chlorella vulgaris for the simultaneous bioremediation of municipal wastewater and production of biodiesel. We tested the effect of wastewater dilution on C. vulgaris growth in filtered and sterilized wastewater, sterilized wastewater, and untreated wastewater. Growth was the greatest in untreated wastewater, suggesting that certain wastewater components, such as bacteria, may promote microalgal growth. We confirmed the presence of beneficial bacteria by denaturing gradient gel electrophoresis analysis and inoculation of wastewater bacteria into microalgal cultures in artificial medium. Furthermore, we employed a semi-continuous cultivation process that successfully combined the advantages of indigenous bacteria with a high level of inoculum. Finally, cells grown in wastewater contained high levels of useful fatty acids. Collectively, our data suggest that it may be feasible to use wastewater-grown C. vulgaris biomass for simultaneous bioremediation and biodiesel production.     

污水生物处理中的噬菌体及其功能研究进展

污水生物处理是一种利用微生物分解污水中的污染物、实现污水净化的方法。噬菌体是侵染细菌的病毒,在污水生物处理系统中广泛存在,它们能够特异性地控制微生物菌群,影响污水处理效果和调控污泥性状。因此,研究污水生物处理中噬菌体的分布及其功能具有重要意义。本文介绍了不同污水生物处理中噬菌体的分布,简要分析了噬菌体分离、培养与鉴定方法及其优缺点,详细总结了噬菌体在污水生物处理中的功能,包括:(1)调节微生物群落结构,影响污水处理效果;(2)作为环境监测的指示生物;(3)控制病原菌、污泥膨胀、污泥发泡和膜污染;(4)减少污泥产量,重点分析了影响噬菌体功能的因素,探讨了污水生物处理中噬菌体功能应用存在的问题及其解决方法,最后对噬菌体未来应用的发展方向进行了展望,以期为污水生物处理技术和工艺的开发与应用提供参考,促进污水处理健康发展。     

可持续的污水处理过程与展望

传统上,污水在处理过程中其所含有的能源和营养物质等也被消耗了。可持续的水处理不仅包括污水无害化处理,还包括能源和营养物的综合回收利用。综合论述了可持续的污水处理概念、理论、方法和污水处理过程中物质回收技术的发展。     

高盐条件下废水生物脱氮除磷及其工艺研究进展

高盐废水是指总含盐量至少为1%的废水,是目前很难处理的废水之一。国内外学者针对高盐废水做了很多研究,我们简要综述了高盐条件下废水的脱氮除磷及工艺进展,希望对高盐条件下废水的同步脱氮除磷研究提供有益的资料。     

Alginate beads provide a beneficial physical barrier against native microorganisms in wastewater treated with immobilized bacteria and microalgae

When the freshwater microalga Chlorella sorokiniana and the plant growth-promoting bacterium Azospirillum brasilense were deployed as free suspensions in unsterile, municipal wastewater for tertiary wastewater treatment, their population was significantly lower compared with their populations in sterile wastewater. At the same time, the numbers of natural microfauna and wastewater bacteria increased. Immobilization of C. sorokiniana and A. brasilense in small (2–4 mm in diameter), polymer Ca-alginate beads significantly enhanced their populations when these beads were suspended in normal wastewater. All microbial populations within and on the surface of the beads were evaluated by quantitative fluorescence in situ hybridization combined with scanning electron microscopy and direct measurements. Submerging immobilizing beads in wastewater created the following sequence of events: (a) a biofilm composed of wastewater bacteria and A. brasilense was created on the surface of the beads, (b) the bead inhibited penetration of outside organisms into the beads, (c) the bead inhibited liberation of the immobilized microorganisms into the wastewater, and (d) permitted an uninterrupted reduction of ammonium and phosphorus from the wastewater. This study demonstrated that wastewater microbial populations are responsible for decreasing populations of biological agents used for wastewater treatment and immobilization in alginate beads provided a protective environment for these agents to carry out uninterrupted tertiary wastewater treatment.     

污水处理和回用技术的应用：中水回用在沈阳的发展前景和存在的问题

为了解决水资源供应严重短缺,缓解污水排放对环境造成的破坏,沈阳市在今后5～10年内将建成中水回用系统,使城市中水回用率达到50％.文中回顾了污水处理和回用技术的发展现状,总结了中水回用的常规技术和新工艺(包括土壤渗滤法、膜生物反应器工艺法、周期循环延时曝气工艺法),并指出土壤渗滤法(SAT)和膜生物反应器(MBR)因其独特的技术优势,在中水回用领域的光明前景.通过列举一些污水回用项目的实际例子,分析了中水回用技术应用所带来的经济和生态效应,并探讨了沈阳市中水回用存在的问题和解决方法.     

Prevalence and fate of giardia cysts in wastewater treatment plants

The present study was conducted to review factors affecting the prevalence and concentration of Giardia in raw wastewater. The removal and inactivation efficiency of Giardia by wastewater treatment technologies was also reviewed. Data published for the prevalence of Giardia in wastewater and the removal by wastewater treatment plants was reviewed. Giardia cysts are highly prevalent in wastewater in various parts of the world, which may reflect the infection rate in the population. In 23 of 30 (76·6%) studies, all of the tested raw wastewater samples were positive for Giardia cysts at concentrations ranging from 0·23 to 100 000 cysts l^?1. The concentration of Giardia in raw wastewater was not affected by the geographical region or the socio‐economic status of the community. Discharge of raw wastewater or the application of raw wastewater for irrigation may result in Giardia transmission. Activated sludge treatment resulted in a one to two orders of magnitude reduction in Giardia, whereas a stabilization pond with a high retention time removed up to 100% of the cysts from wastewater. High‐rate sand filtration, ultrafiltration and UV disinfection were reported as the most efficient wastewater treatment methods for removal and disinfection of Giardia cysts. Wastewater treatment may not totally prevent the environmental transmission of Giardia cysts. The reviewed data show that a combination of wastewater treatment methods may results in efficient removal of Giardia cysts and prevent their environmental transmission.     

固定化微生物细胞技术在废水处理中的应用*

固定化微生物细胞技术是一门新兴的生物技术,中较为全面地介绍了其定义、分类及载体选择。该技术用于处理高浓度有机废水,含氨氮、难降解、重金属废水非常有效,在废水处理领域有着广阔的应用前景。     

Toxicity of high salinity tannery wastewater and effects on constructed wetland plants

The toxicity of high salinity tannery wastewater produced after an activated sludge secondary treatment on the germination and seedling growth of Trifolium pratense, a species used as indicator in toxicity tests, was evaluated. Growth was inhibited by wastewater concentrations >25% and undiluted effluent caused a complete germination inhibition. Constructed wetlands (CWs) with Arundo donax or Sarcocornia fruticosa were envisaged to further polish this wastewater. Selection of plant species to use in CWs for industrial wastewater treatment is an important issue, since for a successful establishment they have to tolerate the often harsh wastewater composition. For that, the effects of this wastewater on the growth of Arundo and Sarcocornia were assessed in pot assays. Plants were subject to different wastewater contents (0/50/100%), and both were resilient to the imposed conditions. Arundo had higher growth rates and biomass than Sarcocornia and may therefore be the preferred species for use in CWs treating tannery wastewater. CWs planted with the above mentioned plants significantly decreased the toxicity of the wastewater, as effluent from the CWs outlet stimulated the growth of Trifolium at concentrations <50%, and seed germination and growth even occurred in undiluted effluent.     

Biodegradability evaluation of dairy effluents originated in selected sections of dairy production

Main goal of the study was present the results of some respirometric measurements of activated sludge biodegrading the substrate in the wastewater originated in selected sections of the dairy processing line. The following dairy production effluents were analyzed in the research: the pumping station wastewater (combined wastewater from all the sections of the dairy factory), the apparatus room wastewater, the butter section wastewater, the milk reception point wastewater, the cheese section wastewater and the cottage cheese section wastewater. Apart from that, sweet and sour whey, which are secondary products of hard cheese and cottage cheese production, respectively, was the subject of the research. The amount of organic matter being oxidized during a 5-day measurement session was calculated on 1g of the activated sludge biomass. The research was conducted at the temperature of 20 degrees C and 35 degrees C at the applied sludge loading rate of A'=0.2 g BOD g(-1) dry mass d(-1), which ensured complete biodegradation. The results indicated a correlation between a technological process of dairy processing, an ultimate outcome of which was the wastewater analyzed, and dairy wastewater biodegradability. The results confirmed that all dairy processing effluents can be treated together, with the exception of whey, whose complex biodegradation demands may cause too much burden to any wastewater treatment technological system and thus should be managed within a separate installation.     

人工污水对秋茄幼苗形态及解剖构造的影响

在温室中建立模拟的秋茄湿地系统, 对照组用人工海水, 其余组分别用3 种不同浓度的人工污水定时定量对模拟系统进行灌溉, 持续1 年。结果表明污水影响植物根系的发育, 胚轴、茎和叶片的形态结构相应发生变化, 这些变化应该是秋茄幼苗为适应污染物而主动产生的, 因此其抗污性较强。     

Geohelminthic infections associated with raw wastewater reuse for agricultural purposes in Beni-Mellal, Morocco

This study was undertaken to determine the possible risk associated with raw wastewater use for agricultural purposes, particularly, the transmission of geohelminthic infections among children of five regions in Beni-Mellal, Morocco. In a randomly selected sample of 1343 children, 740 of them were from five communities using raw wastewater for agriculture, and 603 were from four control communities that do not practice wastewater irrigation. A questionnaire-interview with children and parents was used to collect data on possible demographic, hygiene and behavioral-contact risk factors such as sex, age, family size, parental education, parental occupation, source of water, toilet in house, hand-washing, contact with wastewater and contact with wastewater irrigated land. Ascariasis prevalence was found to be approximately five times higher among children in wastewater-impacted regions compared to control regions. Contact with wastewater and wastewater irrigated land and public water supply were found to be associated with higher infection rates. Trichuris rates did not show a statistically significant difference between the wastewater-impacted and the control regions. In conclusion, raw wastewater use in Beni-Mellal can lead to a high risk of geohelminthic infections. Adequate treatment of wastewater and public health education are highly recommended.     

Biological treatment and toxicity of low concentrations of oily wastewater (bilgewater)

The biodegradability and toxicity of low concentrations of oily wastewater (bilgewater) were tested under simulated sanitary wastewater treatment conditions. This was done to establish the feasibility of a combined shipboard oily and nonoily wastewater treatment system. The biodegradability of oily wastewater was determined by proxy; 14C-labeled dodecane, toluene, and phenanthrene (representing alkane, aromatic, and polyaromatic compounds, respectively) were mineralized in petroleum fuels and lubricants. We found that low concentrations of oily wastewater components were mineralized, even in the presence of more abundant substrates (such as synthetic graywater, containing vegetable oil, detergent, gelatin, and starch). The toxic effects of diesel fuel and several other components of oily wastewater (such as surfactants and a synthetic lubricant) on a na?ve wastewater assemblage was also tested. In concentrations much higher than would be expected under normal shipboard conditions, we found no evidence of toxic effects of the bilgewater compounds tested. Thus, a combined shipboard bilgewater and sanitary wastewater system might be feasible.     

造纸废水对芦苇实生苗生长特性及根系活力的影响

以室内水培的芦苇实生苗为材料,研究6种不同化学需氧量(CODcr)浓度造纸废水处理对芦苇生长指标和根系活力的影响,为利用造纸废水修复自然环境中芦苇实生苗种群提供理论依据。结果表明:(1)不同浓度造纸废水对芦苇各器官鲜(干)重有显著的促进作用,并以中等浓度(300mg.L-1)最为明显;随着造纸废水浓度的增加,废水对芦苇各器官鲜(干)重的促进作用有所减弱,这种减弱幅度在芦苇不同器官上存在差异。(2)高浓度造纸废水导致芦苇根生物量比、根状茎生物量比降低,但影响二者降低的废水浓度存在差异;低浓度造纸废水导致芦苇茎生物量比下降,并使叶生物量比增加。(3)随着造纸废水浓度的增加,芦苇的根系活力呈先上升后下降的趋势,并以CODcr浓度为300mg.L-1时的芦苇的根系活力最强,CODcr浓度为900mg.L-1时最弱。可见,低浓度造纸废水促进了芦苇的生长和根系活力,高浓度废水促进作用减弱甚至会抑制根系活力,并以CODcr浓度为300mg.L-1时芦苇实生苗生长最好。     

Phycoremediation of dairy and winery wastewater using <Emphasis Type="Italic">Diplosphaera</Emphasis> sp. MM1

A new green microalgal species was isolated, identified and investigated for its biomass production and nutrient removal efficiency in dairy and winery wastewater in this study. The 18S rRNA-based phylogenetic analysis revealed that this new strain is a Diplosphaera sp. and was designated strain MM1. The growth of this strain was evaluated in different diluted dairy and winery wastewaters. The highest algal biomass production (up to 2.3 g L^?1) was obtained in dairy wastewater (D3; dairy wastewater 1:2 deionised water) after 14 days of culture. However, for winery wastewater, the highest algal biomass production (up to 1.46 g L^?1) was obtained in wastewater combination W2 (winery wastewater 1:1 deionised water) after 14 days of culture. Turbid dairy wastewater with high concentration of nitrogen and phosphorous slowed down the initial growth of the alga. However, at the end of day 14, biomass production was nearly twofold higher than that of winery wastewater. The findings from both types of wastewater suggest that Diplosphaera sp. MM1 has potential for its application in generating biomass with simultaneous remediation of nutrient-rich wastewater.     

造纸废水活性污泥的微生物群落结构及多样性分析

为探究造纸废水活性污泥中微生物群落结构多样性以及对造纸废水处理效果的影响，利用Illumina MiSeq 高通量测序方法，分析在处理造纸废水过程中，同一运行阶段两个并联氧化沟内活性污泥的微生物群落与多样性组成。结果表明，系统中处理造纸废水的活性污泥在同一废水条件下微生物群落结构总体稳定，优势细菌为绿弯菌门(Chloroflexi)、拟杆菌门（Bacteroidota）、变形菌门（Proteobacteria）、Myxococcota、放线菌门(Actinobacteria）、厚壁菌门(Firmicutes）等。最重要的优势细菌类群为Chloroflexi，相对丰度占比为47.67%~48.22%，远远高于其他废水中Chloroflexi的占比，其中厌氧绳菌纲（Anaerolineae）是其主要成员，占比84.39%~88.34%，可针对性地去除造纸废水中的污染物。造纸废水活性污泥样品中存在大量特殊功能菌群，其在废水中污染物尤其是木质素的去除中发挥着重要作用。     

Removal of natural and xeno-estrogens during conventional wastewater treatment

The ecological impacts of natural estrogens and xenoestrogens in treated wastewater include altered sexual development and sex ratios among continuously exposed organisms. The primary sources of estrogenic activity in wastewater are natural estrogens such as estrone, 17β-estradiol and estriol and synthetic compounds like 17α-ethinylestradiol, alkylphenols and alklphenol ethoxylates. Precursors in raw wastewater can yield estrogenic intermediates during wastewater treatment. All these compounds can be destroyed by biochemical processes, albeit at significantly different rates or under different conditions. That is, estrogenic compounds can be, but are not always, destroyed by conventional wastewater treatment processes, suggesting that conventional processes can be optimized for removal of estrogenic activity from wastewater. Sorption to sludges derived from wastewater treatment affects the fates of hydrophobic xenoestrogens such as nonylphenol, in part because the biodegradability of sorbed contaminants is limited. It may also be possible to tailor sludge stabilization processes to remove trace contaminants, including estrogens. For example, there are significant differences in the efficiencies of aerobic and anaerobic digestion for destruction of alkylphenols and probably other estrogenic compounds with aromatic moieties. Because advanced wastewater treatment is not economically feasible for most communities, there is ample incentive to develop accurate relationships between operational parameters and removal of estrogenic compounds during secondary wastewater treatment.     

Cutting the Wastewater Peaks for Cyclic Batch Production Plants

This paper proposes systematic approaches for cutting the wastewater peaks generated in cyclic batch production plants in which wastewater generation rates and concentration are varied with time. To reduce the investment for the wastewater treatment unit or not to violate the discharge limits, the fluctuations of both flow rate and concentration of the wastewater generated need to be controlled or equalized. Buffer tanks (or basin) are commonly used to regulate the wastewater flow and concentration before the wastewater is sent to treatment units or discharge. The size of the buffer tank needs to be designed properly so that its size is minimized and still has enough capacity to handle various operating conditions. In this paper, conceptual approaches are presented to minimize the size of the buffer tank for either controlling wastewater flow rate or concentration. Mathematical models are proposed for controlling both flow rate and concentration.     

A feasibility study of a Salix viminalis gravel hydroponic system to renovate primary settled wastewater

A Salix viminalis/gravel system based on hydroponics was developed for wastewater renovation in order to avoid the problems of soil damage and pollution associated with long-term application of wastewater to soil. For such a system to work the mineral elements applied must match closely the requirements of the tree species. To examine this the growth and nutrient uptake of S. viminalis in wastewater was compared with that in Long Ashton nutrient solution (1/4 strength). S. viminalis grew more slowly in wastewater than in Long Ashton solution, but exhibited no obvious deficiency or toxicity symptoms. Since industrial wastewaters often contain metals, the extent to which copper might inhibit wastewater treatment in this system was also examined. S. viminalis was grown in wastewater amended with 10 and 100 ppm copper. Trees were unaffected by wastewater with 10 ppm copper when compared to trees grown in wastewater alone. Wastewater containing with 100 ppm copper was too toxic for the trees to thrive and wastewater treatment was reduced. Treatment efficiencies for unamended wastewater were 57.7% for nitrogen, 90.6% for phosphorus and 24.9% for potassium. These efficiencies are much greater than those quoted for a Salix/soil system, and thus Salix/gravel systems may have potential for wastewater treatment in environmentally sensitive areas or situations.