Tea polyphenols can be developed into new types of disinfectants for drinking water. The antibacterial effect of epigallocatechin gallate (EGCG) on Escherichia coli (E. coli) in the presence of Ca2+ is affected by the Ca2+ concentration. The oxidative damage mechanism and oxidative damage process of EGCG in E. coli under the presence of Ca2+ were deeply analyzed under three aspects: reactive oxygen species (ROS), antioxidant system, and oxidative stress response in E. coli to provide a theoretical basis for the use of EGCG as a disinfectant in drinking water disinfection. EGCG leads to excessive production of superoxide anion in E. coli and the presence of Ca2+ promotes further imbalance of superoxide anion in E. coli; Ca2+ has little effect on EGCG hindering the scavenging of hydroxyl radicals in bacteria; EGCG can hinder the effect of antioxidant enzymes in E. coli, and Ca2+ has a particular regulatory effect on antioxidant enzymes, thus hindering the oxidative damage of EGCG to E. coli; Ca2+ can cause the expression of the oxyR and DPS genes, protect bacterial DNA, and prevent EGCG from damaging bacterial DNA. In the presence of a high concentration of Ca2+, it may activate the cell efflux pump through the soxS gene, resulting in E. coli resistance to EGCG.
{"title":"Mechanism of oxidative damage in Escherichia coli caused by epigallocatechin gallate (EGCG) in the presence of calcium ions","authors":"Cuimin Feng, Jiaohua Luo, Xuan-qi Liu, Lu-meng Huang, Hongri Yu, Chang-zheng Wang, Jin-shuang Zhang","doi":"10.2166/aqua.2023.190","DOIUrl":"https://doi.org/10.2166/aqua.2023.190","url":null,"abstract":"\u0000 Tea polyphenols can be developed into new types of disinfectants for drinking water. The antibacterial effect of epigallocatechin gallate (EGCG) on Escherichia coli (E. coli) in the presence of Ca2+ is affected by the Ca2+ concentration. The oxidative damage mechanism and oxidative damage process of EGCG in E. coli under the presence of Ca2+ were deeply analyzed under three aspects: reactive oxygen species (ROS), antioxidant system, and oxidative stress response in E. coli to provide a theoretical basis for the use of EGCG as a disinfectant in drinking water disinfection. EGCG leads to excessive production of superoxide anion in E. coli and the presence of Ca2+ promotes further imbalance of superoxide anion in E. coli; Ca2+ has little effect on EGCG hindering the scavenging of hydroxyl radicals in bacteria; EGCG can hinder the effect of antioxidant enzymes in E. coli, and Ca2+ has a particular regulatory effect on antioxidant enzymes, thus hindering the oxidative damage of EGCG to E. coli; Ca2+ can cause the expression of the oxyR and DPS genes, protect bacterial DNA, and prevent EGCG from damaging bacterial DNA. In the presence of a high concentration of Ca2+, it may activate the cell efflux pump through the soxS gene, resulting in E. coli resistance to EGCG.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82754803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. V., P. R. Priya, Tharkeshwari K., Bineta Mazumder, P. Gayatri, Jackline Neha
In this work, an attempt is made to predict the future water demand of a hilly region. The study area is selected based on the population and the water demand. For this work, Namunaghar and Wandoor Panchayats of Andaman and Nicobar Islands are selected. Initially, preliminary studies such as the current population and future growth and their water demand were analyzed. Also, using a geographical information system (GIS), the study area is located to identify the surface and groundwater sources. From the GIS data, a detailed map is prepared to conduct the physical verification and collect the water quality measurement. From the population forecast, it was identified that 435,000 and 480,300 l of water are required to meet the water demand in the year 2031 Namunaghar and Wander Panchayat, respectively. It also assessed the GIS data and found out potential water sources of 157 (67 wells, 58 ponds, and other minor sources) and 485 (215 wells, 229 ponds, and other minor sources) at Namunaghar and Wandoor Panchayats, respectively. Finally, all the potential water sources were checked for quality for drinking purposes.
{"title":"Assessment of water demand and potential water sources to face future water scarcity of hilly regions","authors":"K. V., P. R. Priya, Tharkeshwari K., Bineta Mazumder, P. Gayatri, Jackline Neha","doi":"10.2166/aqua.2023.212","DOIUrl":"https://doi.org/10.2166/aqua.2023.212","url":null,"abstract":"\u0000 In this work, an attempt is made to predict the future water demand of a hilly region. The study area is selected based on the population and the water demand. For this work, Namunaghar and Wandoor Panchayats of Andaman and Nicobar Islands are selected. Initially, preliminary studies such as the current population and future growth and their water demand were analyzed. Also, using a geographical information system (GIS), the study area is located to identify the surface and groundwater sources. From the GIS data, a detailed map is prepared to conduct the physical verification and collect the water quality measurement. From the population forecast, it was identified that 435,000 and 480,300 l of water are required to meet the water demand in the year 2031 Namunaghar and Wander Panchayat, respectively. It also assessed the GIS data and found out potential water sources of 157 (67 wells, 58 ponds, and other minor sources) and 485 (215 wells, 229 ponds, and other minor sources) at Namunaghar and Wandoor Panchayats, respectively. Finally, all the potential water sources were checked for quality for drinking purposes.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91143802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anita Singh, Monika Mahajan, R. Kothari, Navinderdeep Singh, R. Singh
Population detonation and inflated demand for agricultural products have resulted in the rampant use of pesticides in recent years. These pesticides are used to reduce the number of pesticides by different mechanisms. They have been utilized in agriculture to expand agrarian profit, crop yield, quality, and storage life. The incessant and extensive use of resistant pesticides has contaminated the water bodies, fields, crops, and aquatic biota as well as poses a threat to human health. As a result, stringent regulations and limits are established to monitor the pesticide matrix. The current review focuses on pesticide contamination in the food chain, particularly from the aquatic bodies to fishes and humans. It also discusses strict regulations and limits including maximum residual limits for food items, acceptable daily intake, theoretical maximum daily intake, and estimated carcinogenicity/non-carcinogenicity for fishes and human health risks. In addition to conferring the negative effects of pesticides, this article discusses cost-effective remediation techniques such as phytoremediation, adsorption, the Fenton oxidation method, microalgal/high-rate algal ponds, and nanotechnology with the comparison of their remediation cost.
{"title":"Mechanistic action of pesticides on pests and their consequent effect on fishes and human health with remediation strategies","authors":"Anita Singh, Monika Mahajan, R. Kothari, Navinderdeep Singh, R. Singh","doi":"10.2166/aqua.2023.233","DOIUrl":"https://doi.org/10.2166/aqua.2023.233","url":null,"abstract":"\u0000 Population detonation and inflated demand for agricultural products have resulted in the rampant use of pesticides in recent years. These pesticides are used to reduce the number of pesticides by different mechanisms. They have been utilized in agriculture to expand agrarian profit, crop yield, quality, and storage life. The incessant and extensive use of resistant pesticides has contaminated the water bodies, fields, crops, and aquatic biota as well as poses a threat to human health. As a result, stringent regulations and limits are established to monitor the pesticide matrix. The current review focuses on pesticide contamination in the food chain, particularly from the aquatic bodies to fishes and humans. It also discusses strict regulations and limits including maximum residual limits for food items, acceptable daily intake, theoretical maximum daily intake, and estimated carcinogenicity/non-carcinogenicity for fishes and human health risks. In addition to conferring the negative effects of pesticides, this article discusses cost-effective remediation techniques such as phytoremediation, adsorption, the Fenton oxidation method, microalgal/high-rate algal ponds, and nanotechnology with the comparison of their remediation cost.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78611128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shweta Kalia, Saurabh Samuchiwal, Vidushi Dhaka, A. Malik
The textile industry generates enormous starch effluent from the desizing process that can be utilized as a nutrient source for fungal growth and simultaneous dye decolorization. In the present study, Trichoderma reesei was used as a potential fungal isolate for the decolorization of reactive dyes using a minimal salt media for growth. The dye removal of Reactive blue 13, Reactive red 198, Reactive yellow 176, and Reactive black 5 were 95.35, 88.17, 86.01, and 94.84 mg L−1, respectively, by fungal biomass at 100 mg L−1 of initial dye concentration in 48 h was achieved. T. reesei showed decolorization of dyes at initial concentrations upto 500 mg L−1 with high dye uptake capacity. The glucose (5 g L−1) and yeast extracts (2.5 g L−1) were optimal for maximum dye decolorization. The utilization of starch effluent as an alternative nutrient source supplemented with 3.5 g L−1 glucose as growth media by T. reesei showed >85% of decolorization of Reactive blue 13 (100–200 mg L−1). Thus, starch effluent could be partially supplemented with glucose to support fungal growth and dye decolorization, eliminating the requirement of minimal salts for dye decolorization that follows a sustainable approach.
纺织工业在退浆过程中产生大量的淀粉废水，这些废水可以用作真菌生长的营养源，同时也可以用于染料脱色。在本研究中，里氏木霉被用作一种潜在的分离真菌，用于活性染料的脱色，使用最低盐培养基进行生长。在初始染料浓度为100 mg L−1的条件下，真菌生物量对活性蓝13、活性红198、活性黄176和活性黑5的去除率分别为95.35、88.17、86.01和94.84 mg L−1。T. reesei显示，在初始浓度高达500 mg L−1时，染料脱色能力强，染料吸收能力强。葡萄糖(5 g L−1)和酵母提取物(2.5 g L−1)对染料脱色效果最佳。利用淀粉废水作为替代营养源，并添加3.5 g L−1葡萄糖作为生长培养基，T. reesei对活性蓝13 (100-200 mg L−1)的脱色率>85%。因此，淀粉废水可以部分补充葡萄糖，以支持真菌生长和染料脱色，消除了对染料脱色的最低盐的要求，这是一种可持续的方法。
{"title":"Development and optimization of the dye removal process by Trichoderma reesei using starch effluent as a growth supplement","authors":"Shweta Kalia, Saurabh Samuchiwal, Vidushi Dhaka, A. Malik","doi":"10.2166/aqua.2023.003","DOIUrl":"https://doi.org/10.2166/aqua.2023.003","url":null,"abstract":"The textile industry generates enormous starch effluent from the desizing process that can be utilized as a nutrient source for fungal growth and simultaneous dye decolorization. In the present study, Trichoderma reesei was used as a potential fungal isolate for the decolorization of reactive dyes using a minimal salt media for growth. The dye removal of Reactive blue 13, Reactive red 198, Reactive yellow 176, and Reactive black 5 were 95.35, 88.17, 86.01, and 94.84 mg L−1, respectively, by fungal biomass at 100 mg L−1 of initial dye concentration in 48 h was achieved. T. reesei showed decolorization of dyes at initial concentrations upto 500 mg L−1 with high dye uptake capacity. The glucose (5 g L−1) and yeast extracts (2.5 g L−1) were optimal for maximum dye decolorization. The utilization of starch effluent as an alternative nutrient source supplemented with 3.5 g L−1 glucose as growth media by T. reesei showed >85% of decolorization of Reactive blue 13 (100–200 mg L−1). Thus, starch effluent could be partially supplemented with glucose to support fungal growth and dye decolorization, eliminating the requirement of minimal salts for dye decolorization that follows a sustainable approach.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89610811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Killian Gleeson, S. Husband, John W. Gaffney, J. Boxall
The derivation of information from monitoring drinking water quality at high spatiotemporal resolution as it passes through complex, ageing distribution systems is limited by the variable data quality from the sensitive scientific instruments necessary. A framework is developed to overcome this. Application to three extensive real-world datasets, consisting of 92 multi-parameter water quality time series of data taken from different hardware configurations, shows how the algorithms can provide quality-assured data and actionable insight. Focussing on turbidity and chlorine, the framework consists of three steps to bridge the gap between data and information; firstly, an automated rule-based data quality assessment is developed and applied to each water quality sensor, then, cross-correlation is used to determine spatiotemporal relationships and finally, spatiotemporal information enables multi-sensor data quality validation. The framework provides a method to achieve automated data quality assurance, applicable to both historic and online datasets, such that insight and actionable insight can be gained to help ensure the supply of safe, clean drinking water to protect public health.
{"title":"A data quality assessment framework for drinking water distribution system water quality time series datasets","authors":"Killian Gleeson, S. Husband, John W. Gaffney, J. Boxall","doi":"10.2166/aqua.2023.228","DOIUrl":"https://doi.org/10.2166/aqua.2023.228","url":null,"abstract":"\u0000 The derivation of information from monitoring drinking water quality at high spatiotemporal resolution as it passes through complex, ageing distribution systems is limited by the variable data quality from the sensitive scientific instruments necessary. A framework is developed to overcome this. Application to three extensive real-world datasets, consisting of 92 multi-parameter water quality time series of data taken from different hardware configurations, shows how the algorithms can provide quality-assured data and actionable insight. Focussing on turbidity and chlorine, the framework consists of three steps to bridge the gap between data and information; firstly, an automated rule-based data quality assessment is developed and applied to each water quality sensor, then, cross-correlation is used to determine spatiotemporal relationships and finally, spatiotemporal information enables multi-sensor data quality validation. The framework provides a method to achieve automated data quality assurance, applicable to both historic and online datasets, such that insight and actionable insight can be gained to help ensure the supply of safe, clean drinking water to protect public health.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74159281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Danandeh Mehr, H. Marttila, Ali Torabi Haghighi, Danny Croghan, Nasrin Fathollahzadeh Attar
This article explores the forecasting capabilities of three classic linear and nonlinear autoregressive modeling techniques and proposes a new ensemble evolutionary time series approach to model and forecast daily dynamics in stream dissolved organic carbon (DOC). The model used data from the Oulankajoki River basin, a boreal catchment in Northern Finland. The models that were evolved used both accuracy and parsimony measures including autoregressive (AR), vector autoregressive (VAR), and self-exciting threshold autoregressive (SETAR). The new method, called genetic-based SETAR (GTAR), evolved through the integration of state-of-the-art genetic programming with SETAR. To develop the models, high-resolution DOC concentration and daily streamflow (as the external input for VAR) were measured at the same gauging station throughout the ice free season. The results showed that all the models characterize the DOC dynamics with an acceptable 1-day-ahead forecasting accuracy. Use of the streamflow time series as an exogenous variable did not increase the predictive accuracy of AR models. Moreover, the hybrid GTAR provided the best accuracy for the holdout testing data and proved to be a suitable approach for predicting DOC in boreal conditions.
{"title":"GTAR: a new ensemble evolutionary autoregressive approach to model dissolved organic carbon","authors":"A. Danandeh Mehr, H. Marttila, Ali Torabi Haghighi, Danny Croghan, Nasrin Fathollahzadeh Attar","doi":"10.2166/aqua.2023.235","DOIUrl":"https://doi.org/10.2166/aqua.2023.235","url":null,"abstract":"\u0000 This article explores the forecasting capabilities of three classic linear and nonlinear autoregressive modeling techniques and proposes a new ensemble evolutionary time series approach to model and forecast daily dynamics in stream dissolved organic carbon (DOC). The model used data from the Oulankajoki River basin, a boreal catchment in Northern Finland. The models that were evolved used both accuracy and parsimony measures including autoregressive (AR), vector autoregressive (VAR), and self-exciting threshold autoregressive (SETAR). The new method, called genetic-based SETAR (GTAR), evolved through the integration of state-of-the-art genetic programming with SETAR. To develop the models, high-resolution DOC concentration and daily streamflow (as the external input for VAR) were measured at the same gauging station throughout the ice free season. The results showed that all the models characterize the DOC dynamics with an acceptable 1-day-ahead forecasting accuracy. Use of the streamflow time series as an exogenous variable did not increase the predictive accuracy of AR models. Moreover, the hybrid GTAR provided the best accuracy for the holdout testing data and proved to be a suitable approach for predicting DOC in boreal conditions.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91049284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohit Kumar, R. K. Tiwari, K. Kumar, K. S. Rautela
In the remote and challenging terrain of the Himalayan region, accurate measurement of cyclic snow accumulation and depletion is a significant challenge. To overcome this, an attempt has been made in the present study by applying a statistical analysis of MODIS snow time series data with the Seasonal Autoregressive Integrated Moving Average (SARIMA) model from 2003 to 2018 over the Beas river basin. The Box–Jenkins methodology of forecasting is based on the identification using seasonality, stationarity, ACF, and PACF plots; and estimation based on maximum likelihood techniques; and the last diagnostic checking based on the residual and error values have been used. Later, forecasting models have been proposed separately for the snow accumulation period (October–February) as (1,1,1) (0,1,3)19 and for the snow depletion period (March–September) as (1,1,1) (1,1,2)27 after calibration of the data (2003–2015) and the same were then validated using data (2016–2018). The accuracy assessment of the models has been checked using performance criteria like AIC, MSE, and RSS. The comparison of the forecasting models with the observed data showed a good agreement with R2 of 0.83 and 0.89 for snow accumulation and snow depletion, respectively. This research highlights the potential of utilizing satellite data and statistical modeling to address the challenges of monitoring snow cover in remote and inaccessible regions.
{"title":"Statistical evaluation of snow accumulation and depletion from remotely sensed MODIS snow time series data using the SARIMA model","authors":"Mohit Kumar, R. K. Tiwari, K. Kumar, K. S. Rautela","doi":"10.2166/aqua.2023.231","DOIUrl":"https://doi.org/10.2166/aqua.2023.231","url":null,"abstract":"\u0000 In the remote and challenging terrain of the Himalayan region, accurate measurement of cyclic snow accumulation and depletion is a significant challenge. To overcome this, an attempt has been made in the present study by applying a statistical analysis of MODIS snow time series data with the Seasonal Autoregressive Integrated Moving Average (SARIMA) model from 2003 to 2018 over the Beas river basin. The Box–Jenkins methodology of forecasting is based on the identification using seasonality, stationarity, ACF, and PACF plots; and estimation based on maximum likelihood techniques; and the last diagnostic checking based on the residual and error values have been used. Later, forecasting models have been proposed separately for the snow accumulation period (October–February) as (1,1,1) (0,1,3)19 and for the snow depletion period (March–September) as (1,1,1) (1,1,2)27 after calibration of the data (2003–2015) and the same were then validated using data (2016–2018). The accuracy assessment of the models has been checked using performance criteria like AIC, MSE, and RSS. The comparison of the forecasting models with the observed data showed a good agreement with R2 of 0.83 and 0.89 for snow accumulation and snow depletion, respectively. This research highlights the potential of utilizing satellite data and statistical modeling to address the challenges of monitoring snow cover in remote and inaccessible regions.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91250307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tajikistan is a country in Central Asia with rich water resources. However, drinking water is used for agriculture and other non-drinking purposes owing to the fixed tariff system. Consequently, the overall level of water services has deteriorated and generated revenue is insufficient for operation and maintenance costs. Therefore, this study aimed to improve the quality of water supply services by providing hardware support, such as the construction of wells and the renewal of water distribution pipes. However, because hardware improvement alone cannot sufficiently enhance water supply services, software support to improve the capacity of the Vodokanal (utility) staff, including the preparation of a metered tariff system, was implemented through a technical cooperation project. The project successfully raised customer awareness of water conservation and the water consumption rate was reduced to two-thirds of that before the implementation of the project. Additionally, the water quantity, quality, pressure, and supply hours in the targeted area were significantly improved. Despite the resulting increase in financial burden, customer satisfaction regarding the water supply was enhanced from 51% before the project to 100% in the second half of the project. Simultaneously, the water supply revenue increased by 24% and this increase contributed to sustainable water supply management.
{"title":"Improvement of water utility management in Tajikistan: reduction in water wastage using a metered tariff system","authors":"Ryuji Ogata, Kazumi Matsuda, Tabarzoda Jamshed Avzal, Kimio Abe","doi":"10.2166/aqua.2023.078","DOIUrl":"https://doi.org/10.2166/aqua.2023.078","url":null,"abstract":"\u0000 Tajikistan is a country in Central Asia with rich water resources. However, drinking water is used for agriculture and other non-drinking purposes owing to the fixed tariff system. Consequently, the overall level of water services has deteriorated and generated revenue is insufficient for operation and maintenance costs. Therefore, this study aimed to improve the quality of water supply services by providing hardware support, such as the construction of wells and the renewal of water distribution pipes. However, because hardware improvement alone cannot sufficiently enhance water supply services, software support to improve the capacity of the Vodokanal (utility) staff, including the preparation of a metered tariff system, was implemented through a technical cooperation project. The project successfully raised customer awareness of water conservation and the water consumption rate was reduced to two-thirds of that before the implementation of the project. Additionally, the water quantity, quality, pressure, and supply hours in the targeted area were significantly improved. Despite the resulting increase in financial burden, customer satisfaction regarding the water supply was enhanced from 51% before the project to 100% in the second half of the project. Simultaneously, the water supply revenue increased by 24% and this increase contributed to sustainable water supply management.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78452306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luiz H. Da-Silva-Correa, Kirsten Aasen, Nicole E. Gamm, Rafaela Godoy, Negar Rahmati, H. Buckley
Biofouling is one of the most challenging obstacles faced by reverse osmosis (RO) membrane systems to supply potable water. Currently, biofouling is imperfectly handled by RO feed water pre-chlorination, which is associated with the production of carcinogenic disinfection by-products. To propose a safer alternative to control biofouling in RO drinking water applications, this study investigates the efficacy of five biocides to prevent and remove Pseudomonas aeruginosa biofilms from RO membranes: (1) 2-methyl-4-isothiazolin-3-one (MIT); (2) 2,2-dibromo-3-nitrilopropionamide (DBNPA); (3) sodium bisulfite (SBS); (4) sodium benzoate (SB), and (5) ethyl lauroyl arginate (LAE). Experiments were conducted on the Center for Disease Control (CDC) Biofilm Reactor (CBR) with biocidal dosing estimated on 96-well microtiter plates. Confocal Scanning Laser Microscopy (CLSM) and Scanning Electron Microscopy (SEM) were used to analyze the biocides' anti-biofilm efficacies under dynamic conditions relative to minimum biofilm inhibitory and eradication concentrations. The results in this study indicated that LAE presented the best anti-biofilm efficacies in treating P. aeruginosa biofilms when compared to all studied biocides; it not only prevented biofilm formation (>98%) but also it effectively removed pre-established biofilms (>99%) from RO membrane coupons. Therefore, due to safety and efficacy, LAE is an excellent candidate for controlling biofouling in drinking water RO membrane systems.
{"title":"Efficacy testing of non-oxidizing biocides for polyamide membrane biofouling prevention using a modified CDC biofilm reactor","authors":"Luiz H. Da-Silva-Correa, Kirsten Aasen, Nicole E. Gamm, Rafaela Godoy, Negar Rahmati, H. Buckley","doi":"10.2166/aqua.2023.217","DOIUrl":"https://doi.org/10.2166/aqua.2023.217","url":null,"abstract":"\u0000 Biofouling is one of the most challenging obstacles faced by reverse osmosis (RO) membrane systems to supply potable water. Currently, biofouling is imperfectly handled by RO feed water pre-chlorination, which is associated with the production of carcinogenic disinfection by-products. To propose a safer alternative to control biofouling in RO drinking water applications, this study investigates the efficacy of five biocides to prevent and remove Pseudomonas aeruginosa biofilms from RO membranes: (1) 2-methyl-4-isothiazolin-3-one (MIT); (2) 2,2-dibromo-3-nitrilopropionamide (DBNPA); (3) sodium bisulfite (SBS); (4) sodium benzoate (SB), and (5) ethyl lauroyl arginate (LAE). Experiments were conducted on the Center for Disease Control (CDC) Biofilm Reactor (CBR) with biocidal dosing estimated on 96-well microtiter plates. Confocal Scanning Laser Microscopy (CLSM) and Scanning Electron Microscopy (SEM) were used to analyze the biocides' anti-biofilm efficacies under dynamic conditions relative to minimum biofilm inhibitory and eradication concentrations. The results in this study indicated that LAE presented the best anti-biofilm efficacies in treating P. aeruginosa biofilms when compared to all studied biocides; it not only prevented biofilm formation (>98%) but also it effectively removed pre-established biofilms (>99%) from RO membrane coupons. Therefore, due to safety and efficacy, LAE is an excellent candidate for controlling biofouling in drinking water RO membrane systems.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82855382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xingqi Ding, Zhenxun Yu, Huaqiang Chu, D. Wang, Kun Liu, Buyun Wang, Caihuan Tong, B. Dong
In this study, a dual membrane process (DMP) that combines seven-hole ultrafiltration and nanofiltration was designed and compared to O3-biological activated carbon (O3-BAC) for high-quality drinking water production. The pollutant removal, membrane fouling, long-term operational characteristics, and technical economy were systematically investigated using raw water from Tai Lake, which has a high algae content. The results elucidate that the DMP has superb decontamination. This method has much better removal of turbidity, CODMn, UV254, and algae than O3-BAC. Its removal of ammonia nitrogen and fluorescent substances is slightly lower than that of O3-BAC, but the effluent still satisfies the drinking water standard. The DMP is also much more capable of dealing with high algae-laden raw water. Compared to O3-BAC, the cost of the DMP is 46.4% higher per ton without consuming chemicals, so it is more environmentally friendly. In summary, the DMP offers a promising and effective technology to treat high algae-laden water with the advantages of high stability, reliable effluent, and zero emissions.
{"title":"A pilot study on the dual membrane process of ultrafiltration and nanofiltration to treat algae-laden raw water compared to O3-BAC","authors":"Xingqi Ding, Zhenxun Yu, Huaqiang Chu, D. Wang, Kun Liu, Buyun Wang, Caihuan Tong, B. Dong","doi":"10.2166/aqua.2023.191","DOIUrl":"https://doi.org/10.2166/aqua.2023.191","url":null,"abstract":"\u0000 In this study, a dual membrane process (DMP) that combines seven-hole ultrafiltration and nanofiltration was designed and compared to O3-biological activated carbon (O3-BAC) for high-quality drinking water production. The pollutant removal, membrane fouling, long-term operational characteristics, and technical economy were systematically investigated using raw water from Tai Lake, which has a high algae content. The results elucidate that the DMP has superb decontamination. This method has much better removal of turbidity, CODMn, UV254, and algae than O3-BAC. Its removal of ammonia nitrogen and fluorescent substances is slightly lower than that of O3-BAC, but the effluent still satisfies the drinking water standard. The DMP is also much more capable of dealing with high algae-laden raw water. Compared to O3-BAC, the cost of the DMP is 46.4% higher per ton without consuming chemicals, so it is more environmentally friendly. In summary, the DMP offers a promising and effective technology to treat high algae-laden water with the advantages of high stability, reliable effluent, and zero emissions.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78763504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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