Discover insights from thousands of peer-reviewed papers on microbial electrochemical systems
P. K. Mutiyar, A. Mittal
Desalination and Water Treatment · 2013
Abstract In recent years, pharmaceutical and personal care products (PPCPs) have been detected in various environmental matrices, including ground water, surface water, and municipal wastewater. In order to evaluate the impact of PPCPs on environment, their distribution must be accurately established in these matrices first, as very limited studies have been carried out especially in the Indian subcontinent. In this study, the occurrence and removal of an antibiotic, Amoxicillin, at a sewage treatment plant (STP) located in Delhi has been studied. Amoxicillin was selected for its widespread use as a prescribed over the counter drug. Sampling exercises were carried out over a period of six months so as to cover seasonal variations. Sewage samples were collected from the influents and effluents of STP to determine the occurrences and removal of the amoxicillin. Concentration of amoxicillin in the untreated raw sewage at the STP varied from “not detected” (ND) to 172.6 ng L−1. After treatment, it varied from...
A. Ijaz, Z. Iqbal, M. Afzal
Water Science and Technology · 2016
This investigation reports the quantitative assessment of endophyte-assisted floating treatment wetlands (FTWs) for the remediation of sewage and industrial wastewater. Typha domingensis was used to vegetate FTWs that were subsequently inoculated with a consortium of pollutant-degrading and plant growth-promoting endophytic bacteria. T. domingensis, being an aquatic species, holds excellent potential to remediate polluted water. Nonetheless, investigation conducted on Madhuana drain carrying industrial and sewage water from Faisalabad City revealed the percentage reduction in chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) to be 87% and 87.5%, respectively, within 96 h on coupling the plant species with a consortium of bacterial endophytes. With the endophytes surviving in plant tissue, maximal reduction was obtained in not only the aforementioned pollution parameters but for other major environmental quality parameters including nutrients (N and P), ions (Na+ and K+), Cl-, and SO42- as well, which showed percentage reductions up to 90%, 39%, 77%, 91.8%, 40%, and 60%, respectively. This significant improvement in polluted wastewater quality treated with the proposed method render it safe to be discharged freely in larger water bodies as per the National Environmental Quality Standards (NEQS) of Pakistan or to be reused safely for irrigation purposes; thus, FTWs provide a sustainable and affordable approach for in situ remediation of sewage and industrial wastewater.
Z. A.W., Ularisam
Asian Journal of Chemistry · 2014
Sewage is the main point-source pollutant on a global scale. Sewage, on the one hand, normally contained of biological, chemical and physical composition which is usually high in biochemical oxygen demand, chemical oxygen demand and suspended solid. So, direct discharge of raw or improper treated sewage into the water body is one of the main sources of pollution on a global scale. There are two main objectives of wastewater treatment, one is protecting the environment and the other one is conserving fresh water resources. These days, various physiochemical and biological technique have been employed to treat sewage water such as aerobic and anaerobic biological treatment, membrane filtration, adsorption, chemical coagulation and many others methods. Although the treatment techniques that mentioned above can be applied as the efficient methods, either they took a long period of time or needed a large amount of chemical substance, both ways are less effective in treating sewage water where it requires a short time treatment and an environmental compatibility with free chemical effect. Simple, affordable and efficient sewage wastewater treatment systems are urgently needed in developing countries because most of the conventional technologies currently in use in industrialized nations are too expensive and complex. Electrocoagulation is one of the simple methods to treat wastewater efficiently. This electrochemical treatment seems to be a promising treatment method due to its high effecEffect of High Current Density in Electrocoagulation Process for Sewage Treatment
A. Tsybina, Christoph Wuensch
Detritus · 2018
As of now, the most common applications of sewage sludge treatment and disposal methods globally are in agriculture and deposition in landfills. In particular, landfill disposal causes problems associated with environmental pollution, as well as problems caused by the loss of the chance to recover energy and nutrients out of the sewage sludge. The critical content of hazardous substances in the sewage sludge makes its use in agriculture as fertilizer questionable. Thermal treatment methods offer a solution to these problems because energy can be recovered and used, some hazardous materials can be destroyed or removed, and valuable nutrients such as phosphorus can be utilized in the generated products or recovered from these products. In a first step, the objective and scope of the study and especially the important characteristics of the circular economy when considering sewage sludge treatment possibilities is described. Based on these characteristics for the three investigated thermal treatment methods – incineration, gasification and pyrolysis – a comparative analysis on the basis of a suggested set of criteria (1. cost, 2. energy efficiency, 3. nutrient recovery, 4. product market value and 5. flexibility) was carried out. In the result, incineration of sewage sludge performs best in terms of treatment costs, energy efficiency, nutrient recovery, and flexibility concerning feedstock dry matter content. Pyrolysis performs best in terms of market value of the generated products and flexibility regarding plant size.
Haiyan Wang, Yutong Gong, Y. Wang
RSC Adv. · 2014
Carbon aerogels have attracted considerable attention in fundamental investigation and potential applications in a myriad of fields. We present a novel approach for the synthesis of cellulose-based carbon aerogels by dissolution, gelation, regeneration, freeze-drying and carbonization of cellulose. The carbon aerogels obtained here possess the characteristics of high surface area (500 m2 g−1), hydrophobicity, and fire-resistance. In addition, the carbon aerogels show excellent adsorption capacity and selectivity for removal of oils, organic solvents, a variety of dyes, and heavy ions, so they could be used as promising adsorbents for sewage treatment. Especially for malachite green and Cu(II), the adsorption capacities can reach up to 1947 mg g−1 and 801 mg g−1, respectively, which far surpass other aerogels previous reported.
F. Wang, Jianrong Chen, H. Hong et al.
Water Science and Technology · 2014
Real sewage was continuously treated by a laboratory-scale anaerobic submerged membrane bioreactor (AnSMBR) for over 160 days. Results showed that around 90% of chemical oxygen demand, and 99% of turbidity and total suspended solids in the sewage could be removed by the AnSMBR system. Membrane flux sustained at 11 L/(m(2) h) was realized with biogas sparging. Small flocs from sludge deflocculation in the early operational period caused a high membrane fouling rate, and the high specific filtration resistance of the cake layer appeared mostly attributable to the osmotic pressure effect. The performance results were also compared with those in the literature for upflow anaerobic sludge blanket reactors and aerobic membrane bioreactors for sewage treatment, demonstrating that AnSMBR could provide a desirable alternative for sewage treatment.
J. Burgess, B. Pletschke
Water SA · 2018
Biological wastewater treatment processes can be classified as either aerobic or anaerobic. These two biological treatment processes are each characterised by groups of micro-organisms and their associated enzymes. Hydrolytic enzymes secreted by these micro-organisms are vital for the rate-limiting step of hydrolysis in the treatment of highly polymeric substrates present in sewage sludge. In this mini-review, the effects of mass transfer limitation, metabolic intermediates, extracellular polymeric substances (EPS), electron acceptor conditions and pH and temperature on the activity of these enzymes are summarised. The most salient and current perspectives of the significance and the role that hydrolytic enzymes play in sewage sludge treatment are highlighted.
Feng Gao, Zhao-hui Yang, Chen Li et al.
Desalination and Water Treatment · 2015
AbstractA series of investigations was conducted to treat saline domestic sewage using constructed wetlands. Twelve emergent plant species were planted in experimental units and fed with saline domestic sewage. All species were classified into three clusters using cluster analysis based on the average values of relative growth rate, nutrient uptake, root biomass and activity. The species of Cluster I, including Canna indica, Phragmites australis and Scirpus validus, had strong potential for the purification. The above plants were employed again to treat saline domestic sewage under different influent salinities concentrations. For the influent salinity of 0.5, 1.0 and 1.5%, average treatment performances of planted units were found to be 61.5–70.5% for COD, 59.3–68.4% for –N, 61.9–70.4% for TN and 40.4–47.3% for TP. With increasing influent salinity to 2.0%, the removal efficiencies were dropped significantly. It was similar to the change of the soil enzyme activity in the experiment units. Activities of ...
R. Ferrentino, M. Langone, L. Fiori et al.
Water · 2023
In recent years, increasing attention has been paid to the problem of sewage sludge management and the relevant energy consumption, which represent the main cost items in wastewater treatment plants. Therefore, implementation of technologies that can reduce sludge production and ensure a positive impact on the energy of the entire sewage treatment plant has gained considerable importance in the scientific and technical community. The objective of this study was thus to screen full-scale sludge reduction technologies integrated into both the water line and the sludge line of a municipal sewage treatment plant with a sustainable impact on the overall balance of the plant. The results showed that, within the water line, ultrasound in the recirculation line of the activated sludge allowed for greater reductions in sludge production than the Cannibal and UTN systems, despite the higher energy consumption. CAMBITM, BioThelysTM, ExelysTM and TurboTec® enabled the greatest reductions in sludge production among the technologies integrated into the sludge line, and although they required a large amount of energy, this was partially offset by energy recovery in terms of additional biogas production.
F. Hanum, L. Yuan, H. Kamahara et al.
Frontiers in Energy Research · 2019
Anaerobic digestion is widely considered as an environmentally friendly technology for various organic waste including sewage sludge. Although the implementation of anaerobic digestion as an alternative treatment method for sewage sludge can be seen in many countries, its status in Malaysia is not clear. This study reviewed the current state of sewage sludge treatment in Malaysia and discussed the challenges to promote anaerobic digestion in sewage sludge treatment. Other than the common constraints faced, namely technical, political and economic, the characteristics of sewage sludge in Malaysia is considered to be a factor regarding feasibility. Anaerobic co-digestion is the simultaneous anaerobic digestion of two or more substrates which is a promising possible option to overcome the disadvantages of mono-digestion, and improve the economic viability due to higher methane production. There are a variety of biomass as co-substrate in Malaysia. However, the anaerobic co-digestion of food waste and sewage sludge might be the most feasibility method to overcome such constraints. Adding food waste as co-substrate is suggested as the possible approach to not only improve the process’s performance but also help to handle the increasing volume of food waste in Malaysia. This study aimed to highlight the potential as well as to provide a starting point for further studies regarding the treatment of sewage sludge using anaerobic digestion in Malaysia.
Dinko Đurđević, Maja Trstenjak, Ivona Hulenić
Water · 2020
Sewage sludge management has gained significance in the last several years, due to its nutrient and energy content. However, technology selection is one of the greater challenges because it is not possible to implement a technology that covers all the requirements of the considered environments. Consequently, this paper shows an example of the utilization of an analytical hierarchy process, as a decision-making tool in terms of technology selection, for sewage sludge management in Rijeka, Croatia. The criteria structuring and evaluation process with the description of several possible alternatives for thermal treatment technologies are defined within this research. For the case of Rijeka, the best and most suitable technology for sewage sludge treatment is gasification, which coincides with the results obtained from the analysis of the literature review. According to the results in this paper, the possibilities of the use of this scientific method on the national level for the selection of sewage sludge treatment technology should be considered, due to the simplicity of its use and capability of its adaptation to various situations and areas.
K. Stamatelatou, K. Tsagarakis
IWA Publishing eBooks · 2015
Sewage Treatment Plants: Economic Evaluation of Innovative Technologies for Energy Efficiency aims to show how cost saving can be achieved in sewage treatment plants through implementation of novel, energy efficient technologies or modification of the conventional, energy demanding treatment facilities towards the concept of energy streamlining. The book brings together knowledge from Engineering, Economics, Utility Management and Practice and helps to provide a better understanding of the real economic value with methodologies and practices about innovative energy technologies and policies in sewage treatment plants. This title belongs to Integrated Environmental Technology Series ISBN: 9781780405025 (eBook) ISBN: 9781780405018 (Print)
Malgorzata Siwek, T. Edgecock
Environmental Science and Pollution Research · 2020
A review of the applicability of electron beam water radiolysis for sewage sludge treatment is presented. Electron beam treatment has been proven to be a successful approach to the disinfection of both wastewater and sewage sludge. Nevertheless, before 2000, there were concerns about the perceived high capital costs of the accelerator and with public acceptance of the usage of radiation for water treatment purposes. Nowadays, with increased knowledge and technological development, it may be not only possible but also desirable to use electron beam technology for risk-free sewage sludge treatment, disposal and bio-friendly fertiliser production. Despite the developing interest in this method, there has been no attempt to perform a review of the pertinent literature relating to this technology. It appears that understanding of the mechanism and primary parameters of disinfection is key to optimising the process. This paper aims to reliably characterise the sewage sludge electron beam treatment process to elucidate its major issues and make recommendations for further development and research. Graphical abstract Graphical abstract
M. Tytła
International Journal of Environmental Research and Public Health · 2019
This study aimed to assess the pollution and potential ecological risk of seven heavy metals (Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in the sewage sludge collected from a wastewater treatment plant (WWTP), located in the most industrialized region of Poland (Silesian Voivodeship). The concentrations of heavy metals were determined using inductively coupled plasma optical spectrometry (ICP-OES) and cold vapor atomic absorption spectrometry (CVAAS). The chemical forms (chemical speciation) of heavy metals were determined using the three-step chemical sequential extraction procedure, developed by the Community Bureau of Reference (BCR). To assess the pollution level and potential ecological risk, the following indices were used: Geoaccumulation Index (Igeo), Potential Ecological Risk Factor (ER), Individual Contamination Factor (ICF), modified Risk Assessment Code (RACm), and Ecological Risk Factor (ERF)—the author’s index. Sludge samples were collected at successive stages of processing. The results revealed that the activated sludge process and sludge thickening have a significant impact on heavy metal distribution, while anaerobic digestion and dehydration decrease their mobility. The most dominant metals in the sludge samples were Zn and Cu. However, the content of heavy metals in sewage sludge did not exceed the permissible standards for agricultural purposes. The concentrations of heavy metals bound to the immobile fractions exhibited higher concentrations, compared to those bound to mobile fractions (except Zn). The values of the total indices indicated that sludge samples were moderately to highly contaminated with Zn, Hg, Cd, Cu, and Pb, of which only Hg, Cd, and Cu posed a potential ecological risk, while according to the speciation indices, sludge samples were moderately to very highly polluted with Zn, Cu, Cd, Cr, and Ni, of which Zn, Ni, and Cd were environmentally hazardous. The obtained results proved that assessment of the pollution level and potential ecological risk of heavy metals in sewage sludge requires knowledge on both their total concentrations and their chemical forms. Such an approach will help prevent secondary pollution of soils with heavy metals, which may influence the reduction of health risks associated with the consumption of plants characterized by a high metal content.
Xin Lu, Xu-xiang Zhang, Zhu Wang et al.
PLOS ONE · 2015
This study used 454 pyrosequencing, Illumina high-throughput sequencing and metagenomic analysis to investigate bacterial pathogens and their potential virulence in a sewage treatment plant (STP) applying both conventional and advanced treatment processes. Pyrosequencing and Illumina sequencing consistently demonstrated that Arcobacter genus occupied over 43.42% of total abundance of potential pathogens in the STP. At species level, potential pathogens Arcobacter butzleri, Aeromonas hydrophila and Klebsiella pneumonia dominated in raw sewage, which was also confirmed by quantitative real time PCR. Illumina sequencing also revealed prevalence of various types of pathogenicity islands and virulence proteins in the STP. Most of the potential pathogens and virulence factors were eliminated in the STP, and the removal efficiency mainly depended on oxidation ditch. Compared with sand filtration, magnetic resin seemed to have higher removals in most of the potential pathogens and virulence factors. However, presence of the residual A. butzleri in the final effluent still deserves more concerns. The findings indicate that sewage acts as an important source of environmental pathogens, but STPs can effectively control their spread in the environment. Joint use of the high-throughput sequencing technologies is considered a reliable method for deep and comprehensive overview of environmental bacterial virulence.
Bing Li, F. Ju, Lin Cai et al.
Environmental Science & Technology · 2015
The broad-spectrum profile of bacterial pathogens and their fate in sewage treatment plants (STPs) were investigated using high-throughput sequencing based metagenomic approach. This novel approach could provide a united platform to standardize bacterial pathogen detection and realize direct comparison among different samples. Totally, 113 bacterial pathogen species were detected in eight samples including influent, effluent, activated sludge (AS), biofilm, and anaerobic digestion sludge with the abundances ranging from 0.000095% to 4.89%. Among these 113 bacterial pathogens, 79 species were reported in STPs for the first time. Specially, compared to AS in bulk mixed liquor, more pathogen species and higher total abundance were detected in upper foaming layer of AS. This suggests that the foaming layer of AS might impose more threat to onsite workers and citizens in the surrounding areas of STPs because pathogens in foaming layer are easily transferred into air and cause possible infections. The high removal efficiency (98.0%) of total bacterial pathogens suggests that AS treatment process is effective to remove most bacterial pathogens. Remarkable similarities of bacterial pathogen compositions between influent and human gut indicated that bacterial pathogen profiles in influents could well reflect the average bacterial pathogen communities of urban resident guts within the STP catchment area.
A. M. Mahon, B. O'Connell, M. Healy et al.
Environmental Science & Technology · 2017
Waste water treatment plants (WWTPs) are receptors for the cumulative loading of microplastics (MPs) derived from industry, landfill, domestic wastewater and stormwater. The partitioning of MPs through the settlement processes of wastewater treatment results in the majority becoming entrained in the sewage sludge. This study characterized MPs in sludge samples from seven WWTPs in Ireland which use anaerobic digestion (AD), thermal drying (TD), or lime stabilization (LS) treatment processes. Abundances ranged from 4196 to 15 385 particles kg-1 (dry weight). Results of a general linear mixed model (GLMM) showed significantly higher abundances of MPs in smaller size classes in the LS samples, suggesting that the treatment process of LS shears MP particles. In contrast, lower abundances of MPs found in the AD samples suggests that this process may reduce MP abundances. Surface morphologies examined using scanning electron microscopy (SEM) showed characteristics of melting and blistering of TD MPs and shredding and flaking of LS MPs. This study highlights the potential for sewage sludge treatment processes to affect the risk of MP pollution prior to land spreading and may have implications for legislation governing the application of biosolids to agricultural land.
K. Magnusson, H. Jörundsdóttir, F. Norén et al.
TemaNord · 2016
The report presents results from a study on the role municipal sewage treatment plants (STPs) have as entrance routes for microplastics and other microlitter particles to the marine environment. Microlitter concentrations were analysed in waste water before and after treatment in the STPs, and in the recipient waters where the treated waste water is discharged. Municipal waste water was found to contain a substantial amount of microlitter, but in STPs equipped with chemical and biological treatment most of the litter particles were retained in the sewage sludge. This reduces the impact on the recipient water, but if the sludge is used as fertilizer on farm land the microlitter will still reach the environment. Efforts to reduce the microlitter concentrations should therefore preferably be done in households and other locations where the waste water is originally being formed.
G. Ghosh, S. Hanamoto, N. Yamashita et al.
Polymer Journal · 2016
This study investigated the occurrence and removal of 12 antibiotics (ciprofloxacin, enrofloxacin, levofloxacin, norfloxacin, nalidixic acid, azithromycin, clarithromycin, roxithromycin, lincomycin, novobiocin, sulfamethoxazole, trimethoprim) at four sewage treatment plants (STPs): two STPs in Kyoto, Japan and two STPs in Beijing, China. The STPs differed in design and operation conditions, utilized a variety of secondary treatment processes. The antibiotics were frequently detected in influents and effluents, and ranged from ng/L up to lower μg/L. In influent, clarithromycin (1.1–1.6 μg/L) and levofloxacin (3.6–6.8 μg/L) were detected in the highest concentration in Japanese and Chinese STPs, respectively. The overall elimination of the antibiotics were differed between STPs and ranged from negative to >90%. These data demonstrate that there are detectable levels of antibiotics are discharging from STPs, and only some of these antibiotics are being removed in a significant proportion by STPs. It was also observed that biological nutrient removal based sewage treatment processes (anaerobic–anoxic–oxic: A2O; and anoxic–oxic: AO) have relatively higher antibiotics removal efficiencies than oxidation ditch (OD) processes.
Qilin Wang
ACS Sustainable Chemistry & Engineering · 2017
This letter proposes an innovative roadmap for achieving energy-positive sewage treatment based on sludge treatment using free ammonia (FA i.e. NH3). This FA technology is able to enhance anaerobic energy recovery in the form of methane via pre-treatment of primary sludge and/or secondary sludge. It can also achieve stable mainstream nitrogen removal via nitrite instead of nitrate, thereby increasing organics availability for energy recovery. Energy evaluation suggests that the FA technology could transform sewage treatment plants from energy consumers (energy consumption at 0.27 kWh/m3 sewage treated) to energy exporters (energy export at 0.14 kWh/m3 sewage treated). Economic and environmental evaluations indicate that the FA technology would reduce sewage treatment cost and CO2 emission by $0.056/m3 sewage treated and 0.40 kg CO2/m3 sewage treated, respectively. This FA technology is a sustainable and closed-loop technology, which requires negligible chemical/energy input with FA being a by-product of s...
M. A. Agoro, A. Adeniji, Martins A. Adefisoye et al.
Water · 2020
This study assessed the distribution of five heavy metals (Cd, Pb, Cu, Zn, and Fe) across the various stages of treatment in three selected sewage treatment facilities and their receiving waterbodies in the Eastern Cape Province, South Africa. Aqueous and solid (sludge) samples were collected monthly from September 2015 to February 2016. Quantitation was achieved by atomic absorption spectrometry after necessary sample preparations. Concentrations of heavy metal cations in the sludge generally varied from <DL (below detection limit) to 1.17 mg kg−1, <DL to 0.14 mg kg−1, 27.588 to 69.789 mg kg−1, and <DL to 0.099 mg kg−1 for Cu, Cd, Fe and Pb; while Zn was below detection all through. Similarly, the levels of Cu, Cd, and Fe in the influents, effluents, upstream and downstream across the three plants ranged from <DL–6.588 mg L−1, <DL–0.636 mg L−1, <DL–0.878 mg L−1 and <DL–0.711 mg L−1, respectively; Zn and Pb were less than DL in all the matrices and study locations. All the contaminants were below hazardous levels in all the sludge and aqueous samples except Cd which was higher in effluents and surface waters across the board. Wastewater Treatment Plant (WWTP)-A exhibited better removal capacity for Fe (86.6%), compared to WWTP-B (34.7%) and WWTP-C (56.9%). However, the removal of Cu and Zn was very poor in all the treatment facilities studied. Carcinogenic and non-carcinogenic risks evaluated were sufficiently low. This suggests that the levels of contamination, even with respect to Cd, was minimal. Nevertheless, efforts should be made to keep the concentrations of these contaminants at levels safe for humans and aquatic organisms. Furthermore, the use of the effluents from these facilities for irrigation should be discouraged to prevent unnecessary build-up of metals in the soil and plants grown with such, as well as subsequent bioaccumulation and biomagnification in the food chain.
R. Rajagopal, M. Choudhury, N. Anwar et al.
Water · 2019
The up-flow anaerobic sludge blanket (UASB) process has emerged as a promising high-rate anaerobic digestion technology for the treatment of low- to high-strength soluble and complex wastewaters. Sewage, a complex wastewater, contains 30–70% particulate chemical oxygen demand (CODP). These particulate organics degrade at a slower rate than the soluble organics found in sewage. Accumulation of non-degraded suspended solids can lead to a reduction of active biomass in the reactor and hence a deterioration in its performance in terms of acid accumulation and poor biogas production. Hydrolysis of the CODP in sewage prior to UASB reactor will ensure an increased organic loading rate and better UASB performance. While single-stage UASB reactors have been studied extensively, the two-phase full-scale treatment approach (i.e., a hydrolysis unit followed by an UASB reactor) has still not yet been commercialized worldwide. The concept of treating sewage containing particulate organics via a two-phase approach involves first hydrolyzing and acidifying the volatile suspended solids without losing carbon (as methane) in the first reactor and then treating the soluble sewage in the UASB reactor. This work reviews the available literature to outline critical findings related to the treatment of sewage with and without hydrolysis before the UASB reactor.
Peizhen Chen, Wenjie Zhao, Dongkai Chen et al.
Water · 2022
The improvement of rural living standards in developing countries and the continuous upgrading of the rural industrial economy have prompted the diversification of rural areas and residential forms. Thus, an integrated rural sewage treatment process has gradually become the mainstream technology for rural sewage treatment. Numerous studies have reported the effects of ecological wastewater treatment. Meanwhile, the relevant process technologies, evaluations, and operating models of the integrated rural sewage treatment process have yet to be thoroughly summarized. This review aims to fill these gaps. First, the applicability of artificial wetland, soil infiltration, stabilization pond, and integrated rural sewage treatment process technology in rural sewage treatment are outlined and compared. Second, the process flow, technical characteristics, and economic indicators of typical integrated sewage treatment processes (i.e., Anoxic/Oxic (A/O) process, Membrane Bio-Reactor (MBR) process, biological contact oxidation process, Sequencing Batch Reactor Activated Sludge (SBR) process) are introduced. The engineering application effects of the integrated rural sewage treatment process in different countries are also described. Third, the practical and effective evaluation methods of the integrated rural sewage treatment process are introduced. Bearing in mind the current operation and maintenance management modes of the integrated rural sewage treatment process in developed and developing countries, combined with the national conditions of developing countries, the prospect section provides development proposals for further optimization and improvement of the integrated rural sewage treatment process in developing countries.
H. Kang, Hee-Jin Park, Oh-Kyung Kwon et al.
Environmental Health and Toxicology · 2018
Municipal sewage treatment plants (STPs) are thought to be important point sources of microplastics in freshwater systems and many peer-reviewed articles have been published on this issue since mid-2010s. In this review, we summarize existing literature on the occurrence of microplastics in STPs and experimental methods used for isolation and identification of microplastics. The number concentrations of microplastics in STP influents were 15.1-640 L-1, whereas those in the STP effluents were highly variable and ranged from not detectable to 65 L-1. For most of cases, conventional STPs are removing microplastics very effectively. Fragments and fibers are dominant shapes of microplastics. Thermoplastics (polyethylene and polypropylene) and polyester are the predominant materials recovered. Although further research is needed, size distribution of microplastics in STPs is likely to follow a power law, implying that different studies using different size cutoffs may be compared after establishing a power law relationship.
G. Xue, Mingji Jiang, Hong Chen et al.
Critical Reviews in Environmental Science and Technology · 2019
Abstract It is becoming clear that the wastewater treatment plants (WWTPs) is a key repository for antibiotic resistance genes (ARGs), and WWTPs also represent an important node for limiting ARGs spreading via altering the magnitude and distribution of ARGs in environment. This review provides an overview of the ARGs degradation performance both in sewage sludge and wastewater in WWTPs. The ARGs reduction behaviors during sludge treatment processes including anaerobic digestion (AD), composting, aerobic digestion, bio-drying and air-drying were reviewed, and parameters affecting ARGs reducing efficiency and the probable mechanisms were concluded. In particular, pretreatment approaches such as microwave, thermal hydrolysis and ozone before sludge AD are found to provide the extra benefits for ARGs removal. Additionally, ARGs fates and reduction mechanisms during sewage biological treatments such as anaerobic, aerobic, anaerobic combined with aerobic process and physical-chemical treatment including coagulation, advanced oxidation and disinfection processes were appraised. Furthermore, problems or doubts of previous study are proposed, and some in-depth mechanism researches are anticipated to elucidate the ARGs decay in sewage and sludge treatment process. This can help further enhance the ARGs removal efficiency in WWTPs.
Yeshi Cao, M. Loosdrecht, G. Daigger
Water Practice and Technology · 2020
Since about the 1990s China has achieved remarkable progress in urban sanitation. The country has built very extensive infrastructure for wastewater treatment, with 94.5% treatment coverage in urban areas and legally mandated nation-wide full nutrient removal implemented. However, municipal wastewater treatment plants (WWTPs) in China are still confronted with issues rooted in the unique sewage characteristics. This study compares energy recovery, cost of nutrient removal and sludge production between Chinese municipal WWTPs and those in countries with longer wastewater treatment traditions, and highlights the cause-effect relationships between Chinese sewage characteristics – high inorganic suspended solids (ISS) loads, and low COD and C/N ratio, and municipal WWTP process performance in China. Integrated design and operation guidelines for municipal WWTPs are imperative in relation to the unique sewage characteristics in China. Cost-effective measures and solutions are proposed in the paper, and the potential benefits of improving the sustainability of municipal WWTPs in China are estimated.
Michael F. Meyer, S. Powers, S. Hampton
Environmental Science & Technology · 2019
Pharmaceuticals and personal care products (PPCPs) garner increasing attention globally for both their usefulness as indicators of human waste and their potency as emerging organic toxicants. Three decades of rapid increase in PPCP study combined with an increasing number of PPCPs on the global market have created opportunity (1) to review trends in diversity of compounds, sewage treatment techniques (STTs), and ecosystems investigated as well as (2) to identify knowledge gaps in the literature. We conducted a quantitative evidence synthesis of 6,517 abstracts from primary articles in the environmental PPCP literature by examining relative abundance of specific PPCP classes, STTs, and ecosystem types. Our results demonstrate that non-prescription drugs and antibiotics dominated PPCP abstracts, appearing in 51% and 39% of reviewed abstracts respectively, in comparison to hormones (18%), prescription drugs (18%), fragrances (0.3%), and antioxidants (0.0%), which can all elicit physiological and ecological responses even at low concentrations. References to centralized STTs (e.g., activated sludge - 37%) were more frequent than decentralized STTs (e.g., septic - 2%), despite decentralized STTs being common and frequently high impact sources of sewage pollution worldwide. Freshwater lotic systems (63%) were more prevalent than freshwater lentic (24%) and terrestrial (20%) systems. This discrepancy is notable because the longer residence times of lentic and terrestrial systems may enable PPCPs to concentrate and thus increase risk of biological consequences. These results highlight distinct opportunities to address knowledge gaps in the environmental PPCP literature, including underrepresented compounds (e.g., fragrances), sewage treatment techniques (e.g., septic systems), and ecosystem types (e.g., lakes).
Junxue Zhang, Lin Ma
Water · 2020
Due to excessive resource consumption and pressing environmental issues of the sewage treatment industry, there is extensive attention in China. Given the unique craft production process in the sewage treatment system, a series of integral emergy indicators have been used to evaluate the environmental sustainability based on infrastructure construction and operation stage emergy analysis. Taking a new typical sewage treatment plant as an example, this paper performed a case study. The results illustrate that (1) the infrastructure construction process emergy (approximate 92.6%) is more critical than sewage treatment process emergy; (2) nonrenewable resource is the primary factor for the emergy analysis, followed by energy (23.5%) and purchased supply (7%); (3) cement, steel, and gravel have dominant impacts on the nonrenewable resource emergy; (4) the emergy sustainability index is 0.001101, which displays weak environmental sustainability; (5) the unit emergy value (UEV) of the new sewage treatment plant is 3.40 × 1012 sej/m3; (6) sensitivity analysis results of the hypothesis demonstrate that nonrenewable resources have significant fluctuations (6.903%) while, for the indicators, emergy sustainability index (ESI) (4.8072%) has the most significant impact; and (7) wastewater is a major contributor. In light of comprehensive discussions, two positive measures are proposed in order to ameliorate the environmental sustainability.
Rui Zhang, Huawei Zheng, Hui Zhang et al.
International Journal of Environmental Research and Public Health · 2020
Rural domestic sewage treatment is not only an important part of the renovation of rural human settlements, but also a major measure to revitalize those areas. In the absence of extensive participation by farmers, it is difficult to achieve desired results. From the theoretical analysis of the influence of social capital on farmers’ participation, and based on the survey data of farmers in Nanjing, Jiangsu Province, this study used a logistic model to analyze the influence of social capital and personal, family, and awareness characteristics of farmers on their participation levels. Social capital plays a significant role in promoting farmers’ participation, and the contribution of its core variables is in the following order: social norms > social trust > social networks. Among the control variables, the need for domestic sewage treatment, participation in environmental training, educational level, and participation in a village cadre significantly enhance farmers’ participation levels. Consequently, promotion of rural domestic sewage treatment should include improvement of farmers’ social trust, social norms, and social networks, to enhance social capital. Publicity and education should be reinforced, and environmental training should be carried out to improve farmers’ awareness and sense of responsibility, leading them to active participation.
Tae-Jin Park, Seung-Hyun Lee, Myung-Sung Lee et al.
Water · 2020
Microplastics are ubiquitously found in freshwater and marine environments worldwide. In particular, wastewater treatment plants (WWTPs) or sewage treatment plants (STPs) have been recognized as a main source of microplastics in the receiving freshwater. However, only a few studies have been conducted to examine the impact of these facilities on receiving waters. In this study, we investigated the distribution of microplastics in surface water, fish, and sediment near a sewage treatment plant (STP) in the Tanchon stream, one of the main tributaries flowing into the Han River, Korea. The concentration of microplastics in water varied spatially and temporarily, ranging between 5.3 and 87.3 particles/m3 (31.4 ± 28.5 particles/m3). In fish, the concentration in upstream and downstream sites was 7.3 ± 7.3 and 12.4 ± 17.9 particles/fish, respectively. Spatially, the downstream site was the most polluted with microplastics in water and fish. The concentration of microplastics was positively correlated with fish body length and weight. In sediment, microplastic concentration in upstream and downstream sites was 493.1 ± 136.0 and 380.0 ± 144.2 particles/kg, respectively. The contribution of upstream to the microplastic load in downstream was 15.8% in dry season (April), which was higher than that of STP effluent and Yangjaechon creek. Meanwhile, the highest load was observed in STP effluent (5.1%) in rainy season (August). Microplastics were more abundant in water in the rainy season (37.4 ± 37.0 particles/m3) than in the dry season (28.2 ± 22.2 particles/m3). Polyethylene (49%) and polypropylene (18%) were the most abundant polymer types in water, fish, and sediment. Regarding shape of microplastics, fragments were dominant (95%) over fiber and film in water, fish, and sediment.
Justyna Szulc, Małgorzata Okrasa, K. Majchrzycka et al.
Toxins · 2021
Despite the awareness that work in the sewage treatment plant is associated with biological hazards, they have not been fully recognised so far. The research aims to comprehensively evaluate microbiological and toxicological hazards in the air and settled dust in workstations in a sewage treatment plant. The number of microorganisms in the air and settled dust was determined using the culture method and the diversity was evaluated using high-throughput sequencing. Endotoxin concentration was assessed with GC-MS (gas chromatography-mass spectrometry) while secondary metabolites with LC-MS/MS (liquid chromatography coupled to tandem mass spectrometry). Moreover, cytotoxicity of settled dust against a human lung epithelial lung cell line was determined with the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and UHPLC-Q-ToF-UHRMS (ultra-high-performance liquid chromatography-quadrupole time-of-flight ultrahigh-resolution mass spectrometry) analysis was performed to determine the source of cytotoxicity. The total dust concentration in the sewage treatment plant was low and ranged from 0.030 mg m−3 to 0.044 mg m−3. The highest microbiological contamination was observed in sludge thickening building and screenings storage. Three secondary metabolites were detected in the air and sixteen in the settled dust. They were dominated by compounds typical of lichen and plants and Aspergillus, Penicillium and Fusarium genera mould. The settled dust from the sludge thickening building revealed high cytotoxicity to human lung epithelial cells A-549 (IC50 = 6.98 after 72 h). This effect can be attributed to a biocidal compound—didecyldimethylammonium chloride (DDAC-C10) and seven toxic compounds: 4-hydroxynonenal, carbofuran, cerulenin, diethylphosphate, fenpropimorph, naphthalene and onchidal. The presence of DDAC-C10 and other biocidal substances in the sewage treatment plant environment may bring negative results for biological sewage treatment and the natural environment in the future and contribute to microorganisms’ increasing antibiotics resistance. Therefore, the concentration of antibiotics, pesticides and disinfectants in sewage treatment plant workstations should be monitored.
Jiaheng Zhao, Bing Li, Pin Lv et al.
Frontiers of Environmental Science & Engineering · 2021
The distribution of antibiotic resistance genes (ARGs) has been intensively studied in large-scale wastewater treatment plants and livestock sources. However, small-scale decentralized sewage treatment facilities must also be explored due to their possible direct exposure to residents. In this study, six wastewater treatment facilities in developed rural areas in eastern China were investigated to understand their risks of spreading ARGs. Using metagenomics and network analysis tools, ARGs and bacterial and viral communities were identified in the influent (INF) and effluent (EFF) samples. The dominant ARGs belonged to the bacitracin class, which are different from most of municipal wastewater treatment plants (WWTPs). The dominant hosts of ARGs are Acidovorax in bacterial communities and Prymnesiovirus in viral communities. Furthermore, a positive relationship was found between ARGs and phages. The ARGs significantly correlated with phages were all hosted by specific genera of bacteria, indicating that phages had contributed to the ARG’s proliferation in sewage treatment facilities. Paying significant concern on the possible enhanced risks caused by bacteria, viruses and their related ARGs in decentralized sewage treatment facilities is necessary.
Lu Lu, Hui Zheng, Jing Jie et al.
Complex & Intelligent Systems · 2021
To solve the problem of high-energy consumption in activated sludge wastewater treatment, a reinforcement learning-based particle swarm optimization (RLPSO) was proposed to optimize the control setting in the sewage process. This algorithm tries to take advantage of the valid history information to guide the behavior of particles through a reinforcement learning strategy. First, an elite network is constructed by selecting elite particles and recording their successful search behavior. Then the network is trained and evaluated to effectively predict the particle velocity. In the periodic wastewater treatment process, the RLPSO runs repeatedly according to the optimized cycle. Finally, RLPSO was tested based on Benchmark Simulation Model 1 (BSM1) of sewage treatment, and the simulation results showed that it could effectively reduce the energy consumption on the premise of ensuring qualified water quality. Furthermore, the performance of RLPSO was analyzed using the benchmarks with higher dimension, which verifies the effectiveness of the algorithm and provides the possibility for RLPSO to be applied to a wider range of problems.
Zhiwei Guo, Yu Shen, A. Bashir et al.
International Journal of Intelligent Systems · 2021
Intelligent algorithms‐driven industrial decision systems have been a general demand for modeling complex sewage treatment processes (STP). Existing researches modeled complex STP with the use of various neural network models, yet neglecting the fact that latent and occasional relations exist inside complex STP. To deal with the challenge, this paper proposes graph embedding‐based intelligent industrial decision for complex STP (GE‐STP). The graph embedding (GE) scheme is employed to enhance feature extraction and neural computing structure is utilized to simulate uncertain biochemical transformation inside STP. The introduction of GE can not only improves the fineness of feature spaces, but also improves the representative ability of models towards complex industrial processes. On this basis, the GE‐STP is evaluated on a real‐world data set collected from a realistic sewage treatment plant equipped with a set of Internet of Things devices. And some typical neural network models that have been utilized for modeling complex STP, are selected as baseline methods. Three groups of experiments show that efficiency of the GE‐STP exceeds baselines about 6%–12%, and that the GE‐STP is not susceptible to parameter changing.
Wei Zheng, Yan Ming Yang, Yun Long Li et al.
Advanced Materials Research · 2014
The process technique and design parameters of project of Solar Ozonic Ecological Sewage Treatment Plant (short for SOESTP) which consists of anaerobic reactor, horizontal subsurface flow (HSSF) constructed wetlands(CWs) and the combination of solar power and ozone disinfection are described, the paper further examines the removal efficiency for treating rural domestic sewage, running expense and recycling ability of product water. The results show that the average percentage removal values of CODcr，BOD 5 ，SS，TN，NH 3 -N，TP range from 95.6% to 98.0%, 96.0% to 98.7%, 93.1% to 96.1%, 97.0% to 98.9%, 96.9% to 99.5%, 98.2% to 99.6%, respectively, the reduction of fecal coliform (FC) reaches 99.9%, the effluent quality meets the first level A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant（GB18918-2002）. The running cost of SOESTP is 0.063yuan/ m 3 , saves much more than traditional sewage treatment, and the ozone water obtained from the reservoir will be an ideal choice for disinfection .The system has characteristics of easy manipulation, low operating cost, achieving advanced water, energy conservation and environment protection, is thought to be very suitable for use as the promotion of rural small - scale sewage treatment.
Heena Tabassum, Allika Sailaja, Huda Afreen et al.
Sustainable Development · 2023
This chapter provides a brief overview of nanomaterials, including classification, shape and structure, nanomaterial types, and applications in the degradation of recalcitrant organic contaminants. With the rapid advancement of nanotechnology science, the use of nanomaterials in environmental applications, particularly water treatment, has piqued the scientific community’s interest in recent decades. Nanomaterials have unique properties such as surface-to-volume ratio, quantum effect, low band-gap energy, and so on, which enhance catalytic performance. Wastewater treatment is a critical task of the twenty-first century since it protects the health of our environment and living beings. Because of its ability to affect both living and nonliving organisms, wastewater is always viewed as a serious source of environmental contamination. Many physical, biological, and chemical modes of treatment are implied to comply with wastewater discharge standards set by competent national agencies for environmental protection.
Ernest Mbamalu Ezeh, Peter Chinedu Agu, Epere Aworabhi
Sewage - Management and Treatment Techniques · 2024
Sewage treatment is crucial to safeguard public health and the environment. Various techniques are available for treating wastewater, and the selection of one often depends on factors like the wastewater composition, environmental conditions, and treatment objectives. One of the most widely used methods of biological treatment for sewage is activated sludge, which employs aerobic bacteria to degrade organic matter. This process involves blending wastewater with a mixture of bacteria and flocs, with the bacteria consuming the organic matter to produce clear water while the flocs settle. Another commonly employed method is anaerobic digestion, which employs anaerobic bacteria to decompose organic matter in the absence of oxygen. These methods generate biogas, containing methane and carbon dioxide, and digestate, a nutrient-rich sludge suitable as soil amendment or fertilizer. This chapter explores the mechanisms and applications of activated sludge and anaerobic digestion in biological sewage treatment, highlighting their advantages and downsides, the factors that influence their performance, such as pH, temperature, and substrate concentration. It covers the latest improvements in biological sewage treatment, including the use of new microbial strains and hybrid treatment systems.
Zvezdimira Tsvetanova, Rosen Boshnakov
Water · 2024
Waste water treatment plants (WWTP) are considered as a hotspot for the acquisition and dissemination of antimicrobial resistance (AMR). The present study aimed to assess the AMR rate of the waste water microbiome in a selected WWTP and the treatment efficiency. Culture-dependent and PCR methods were used in the AMR study of raw and treated waste water (TWW) microbiomes. The population proportion of heterotrophic plate count (HPC) bacteria resistant to five antibiotic classes was assessed, as well as the AMR phenotype of a total of 238 Enterobacteriaceae and 259 Enterococcus spp. strains. Waste water treatment increased tetracycline- and ciprofloxacin-resistant bacteria by 67% and 61%, as well as the incidence of Enterobacteriaceae resistant to ciprofloxacin, co-trimoxazole, and cephalosporins. Multiple resistance increased, and 8.8% of TWW isolates exhibited an ESBL-producing phenotype, most often encoded by blaTEM and blaCTX-M genes. The most common resistance among Enterococcus spp. was to erythromycin and tetracycline, and despite the increased AMR rate among TWW isolates, only the increase in tetracycline resistance and the decrease in high-level gentamicin resistance were significant. All parameters analysed demonstrated limited removal of resistant HPC or faecal indicator bacteria in the studied WWTP and a positive selective effect towards some of them, most often to ciprofloxacin.
Xinhui Xia, Fengyi Zhu, Jianju Li et al.
Frontiers in Chemistry · 2020
High levels of toxic organic pollutants commonly detected during domestic/industrial wastewater treatment have been attracting research attention globally because they seriously threaten human health. Sulfate-radical-based advanced oxidation processes (SR-AOPs) have been successfully used in wastewater treatment, such as that containing antibiotics, pesticides, and persistent organic pollutants, for refractory contaminant degradation. This review summarizes activation methods, including physical, chemical, and other coupling approaches, for efficient generation of sulfate radicals and evaluates their applications and economic feasibility. The degradation behavior as well as the efficiency of the generated sulfate radicals of typical domestic and industrial wastewater treatment is investigated. The categories and characteristics of the intermediates are also evaluated. The role of sulfate radicals, their kinetic characteristics, and possible mechanisms for organic elimination are assessed. In the last section, current difficulties and future perspectives of SR-AOPs for wastewater treatment are summarized.
S. Kurniawan, S. R. Abdullah, M. Imron et al.
International Journal of Environmental Research and Public Health · 2020
The utilization of metal-based conventional coagulants/flocculants to remove suspended solids from drinking water and wastewater is currently leading to new concerns. Alarming issues related to the prolonged effects on human health and further pollution to aquatic environments from the generated nonbiodegradable sludge are becoming trending topics. The utilization of biocoagulants/bioflocculants does not produce chemical residue in the effluent and creates nonharmful, biodegradable sludge. The conventional coagulation–flocculation processes in drinking water and wastewater treatment, including the health and environmental issues related to the utilization of metal-based coagulants/flocculants during the processes, are discussed in this paper. As a counterpoint, the development of biocoagulants/bioflocculants for drinking water and wastewater treatment is intensively reviewed. The characterization, origin, potential sources, and application of this green technology are critically reviewed. This review paper also provides a thorough discussion on the challenges and opportunities regarding the further utilization and application of biocoagulants/bioflocculants in water and wastewater treatment, including the importance of the selection of raw materials, the simplification of extraction processes, the application to different water and wastewater characteristics, the scaling up of this technology to a real industrial scale, and also the potential for sludge recovery by utilizing biocoagulants/bioflocculants in water/wastewater treatment.