scholarly journals Application of solar disinfection for treatment of contaminated public water supply in a developing country: field observations

2012 ◽  
Vol 11 (1) ◽  
pp. 135-145 ◽  
Author(s):  
Atif Mustafa ◽  
Miklas Scholz ◽  
Sadia Khan ◽  
Abdul Ghaffar
Keyword(s):  
Drinking Water ◽  
Field Experiments ◽  
Low Cost ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Batch Reactors ◽  
Treated Water ◽  
Solar Disinfection ◽  
Point Of Use ◽  
Guideline Value

A sustainable and low-cost point-of-use household drinking water solar disinfection (SODIS) technology was successfully applied to treat microbiologically contaminated water. Field experiments were conducted to determine the efficiency of SODIS and evaluate the potential benefits and limitations of SODIS under local climatic conditions in Karachi, Pakistan. In order to enhance the efficiency of SODIS, the application of physical interventions were also investigated. Twenty per cent of the total samples met drinking water guidelines under strong sunlight weather conditions, showing that SODIS is effective for complete disinfection under specific conditions. Physical interventions, including black-backed and reflecting rear surfaces in the batch reactors, enhanced SODIS performance. Microbial regrowth was also investigated and found to be more controlled in reactors with reflective and black-backed surfaces. The transfer of plasticizer di(2-ethylhexyl)phthalate (DEHP) released from the bottle material polyethylene terephthalate (PET) under SODIS conditions was also investigated. The maximum DEHP concentration in SODIS-treated water was 0.38 μg/L less than the value of 0.71 μg/L reported in a previous study and well below the WHO drinking-quality guideline value. Thus SODIS-treated water can successfully be used by the people living in squatter settlements of mega-cities, such as Karachi, with some limitations.

scholarly journals Speeding up solar disinfection (SODIS): effects of hydrogen peroxide, temperature, pH, and copper plus ascorbate on the photoinactivation of E. coli

2007 ◽  
Vol 6 (1) ◽  
pp. 35-51 ◽  
Author(s):  
Michael B. Fisher ◽  
Christina R. Keenan ◽  
Kara L. Nelson ◽  
Bettina M. Voelker
Keyword(s):  
Hydrogen Peroxide ◽  
Field Experiments ◽  
Elevated Temperatures ◽  
Low Cost ◽  
Drinking Water Treatment ◽  
Copper Metal ◽  
Solar Disinfection ◽  
E Coli ◽  
Point Of Use ◽  
Cloudy Weather

Solar disinfection, or SODIS, shows tremendous promise for point-of-use drinking water treatment in developing countries, but can require 48 h or more for adequate disinfection in cloudy weather. In this research, we show that a number of low-cost additives are capable of accelerating SODIS. These additives included 100-1000 μM hydrogen peroxide, both at room temperature and at elevated temperatures, 0.5 – 1% lemon and lime juice, and copper metal or aqueous copper plus ascorbate, with or without hydrogen peroxide. Laboratory and field experiments indicated that additives might make SODIS more rapid and effective in both sunny and cloudy weather, developments that could help make the technology more effective and acceptable to users.

scholarly journals Effectiveness of solar disinfection for household water treatment: an experimental and modeling study

2021 ◽  
Author(s):  
Md. Rezaul Karim ◽  
Md. Habibur Rahman Bejoy Khan ◽  
Md. Abu-Sa-Ad Akash ◽  
Shahriar Shams
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Low Cost ◽  
Weibull Model ◽  
Bacterial Inactivation ◽  
Household Water Treatment ◽  
Treated Water ◽  
Solar Disinfection ◽  
Pet Bottles ◽  
Household Water

Abstract Solar disinfection (SODIS) is a simple and low-cost household water treatment (HWT) option used for disinfection of drinking water. In this study, the bacterial inactivation potential of SODIS was evaluated under the solar irradiance observed in different seasons in Bangladesh according to WHO evaluation protocol of HWT, and the SODIS experiments were conducted for both transmissive and reflective reactors using PET bottles and plastic bags. In summer, log reduction value (LRV) more than 5 was observed for the transmissive PET reactors for 6 to 8 hr exposure to sunlight and the treated water complied with the microbial standard of zero colony forming units/100 mL in drinking water. In monsoon and winter, LRV > 4 can be achieved for 16 hr and 8 hr exposure to sunlight, respectively, using reflective reactors. The plastic bag was found to be more effective than PET. A safe exposure time was estimated from the Weibull model to be maintained for SODIS application to achieve 4.0 LRV and also to prevent the re-growth of microorganisms in the treated water. A significant re-growth of microorganisms was observed in the treated water, thus SODIS with other HWT processes can be recommended for use in communities with an unsafe drinking water supply.

scholarly journals Efficiency of Arsenic and Iron Removal Plants (AIRPs) for Groundwater Treatment in Rural Areas of Southwest Bangladesh

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 354
Author(s):  
Md. Aminur Rahman ◽  
Sazal Kumar ◽  
A. S. M. Fazle Bari ◽  
Abhishek Sharma ◽  
Mohammad Mahmudur Rahman
Keyword(s):  
Drinking Water ◽  
Cancer Risk ◽  
Monsoon Season ◽  
Cancer Risk Assessment ◽  
Future Research ◽  
Treated Water ◽  
Post Monsoon ◽  
Drinking Water Standard ◽  
Guideline Value ◽  
Removal Efficiencies

Arsenic (As) removal plants were installed in As-endemic areas of Bangladesh to remove As from well water. In many cases, these removal plants did not perform satisfactorily. This study evaluated the efficiency of 20 As and iron (Fe) removal plants (AIRPs) during pre- and post-monsoon conditions in rural Bangladesh. Results revealed that As removal efficiencies ranged from 67% to 98% and 74 to 93% during the pre- and post-monsoons periods, respectively. In the post-monsoon season As removal at individual AIRP sites was on average (4.01%) greater than in the pre-monsoon season. However, two removal plants were unable to remove As below 50 µg L−1 (Bangladesh drinking water standard) during pre-monsoon, while 11 samples out of 20 were unable to remove As below the WHO provisional guideline value of 10 µg L−1. During post-monsoon, none of the samples exceeded 50 µg L−1, but eight of them exceeded 10 µg L−1. The Fe removal efficiencies of AIRPs were evident in more than 80% samples. Although As removal efficiency was found to be substantial, a cancer risk assessment indicates that hazard quotient (HQ) and carcinogenic risk (CR) of As in treated water for adults and children are above the threshold limits. Thus, additional reductions of As concentrations in treated water are needed to further reduce the excess cancer risk due to As in drinking water. Since 55% and 40% of the AIRPs were unable to remove As < 10 µg L−1 during pre-monsoon and post-monsoon, further improvement including changes in AIRP design, regular cleaning of sludge, and periodic monitoring of water quality are suggested. Future research is needed to determine whether these modifications improve the performance of AIRPs.

scholarly journals Influence of the growth regulator “Regoplant” and microfertilizer “Ultramag Kombi” on photosynthetic activity of potatoes in the forest-steppe zone Republic of North Ossetia-Alania

2021 ◽  
Vol 210 (07) ◽  
pp. 55-65
Author(s):  
Larisa Ikoeva ◽  
Oksana Haeva
Keyword(s):  
Growth Regulator ◽  
Field Experiments ◽  
Photosynthetic Activity ◽  
Low Cost ◽  
Weather Conditions ◽  
Steppe Zone ◽  
Practical Significance ◽  
Forest Steppe ◽  
Photosynthetic Productivity ◽  
North Ossetia

Abstract. The purpose of the work is to study the influence of the growth regulator “Regoplant” and microfertilizer “Ultramag Kombi” on the photosynthetic productivity of the potatoes of the Barna variety based on the results of field experiments in the forest-steppe zone Republic of North Ossetia-Alania. Methods. Studies on the tasks were carried out in 2018–2020. at the experimental site of the NCRIMFA branch of the VSC of RAS in the conditions of the forest-steppe zone Republic of North Ossetia-Alania according to generally accepted methods. The soil of the experimental plot is medium-power heavy loamy leached chernozem, lined with pebbles. Results. It is established, that biological products under identical soil and weather conditions assisted different progress of plants and approach of phases of vegetation. For all variants of the experiment, the number of stems increased by 0,3–0,7 pcs., the height of the stems of potato plants – by 3,8–4,9 cm in comparison with the control. An intense increase in the mass of tops occurred when using a tank mixture (growth regulator “Regoplant” (25 ml/ha) + microfertilizer “Ultramag Combi” (0,75 l/ha)) – by 74 g/bush, or 15.5 % compared with the control variant. During the growing season, the sum of the photosynthetic potential (FP) was 1,070 thousand m2 •days/ha in the control, and on average 1198–1406 thousand m2•days/ha in the experimental variants. The greatest accumulation of dry matter was noted when using a tank mixture – 917 g/m2. The maximum pure photosynthetic productivity was observed in experimental variant IV – 6,52 g/m2•day compared to the control option. Scientific novelty. For the first time in the forest-steppe zone Republic of North Ossetia-Alania the effect of the growth regulator “Regoplant” and microfertilizer “Ultramag Kombi” on photosynthetic activity of potatoes was studied. Practical significance. The studies carried out make it possible to recommend in potato production the use of a tank mixture of an effective growth regulator “Regoplant” at a dose of 25 ml/ha and microfertilizer “Ultramag Combi” at a dose of 0,75 l/ha, as an ecologically safe and low-cost agricultural method when processing vegetative plants, providing an increase in yield and quality of tubers.

scholarly journals Impact of pretreatment on defluoridation of drinking water by bone char adsorption

2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Adam Teusner ◽  
Rhett Butler ◽  
Pierre Le Clech
Keyword(s):  
Drinking Water ◽  
Low Cost ◽  
Feed Solution ◽  
Hollow Fibre ◽  
Human Consumption ◽  
Bone Char ◽  
Subsequent Removal ◽  
Filter Performance ◽  
Point Of Use ◽  
Gravity Driven

Fluoride concentrations in drinking water in excess of 1.5 mg L-1 are unsafe for human consumption. To reduce excess fluoride intake, developing countries must use low-cost, point-of-use defluoridation techniques. Although previous work has extensively assessed defluoridation using bone char (BC), most of the advanced studies have been based on the use of fluoridated distilled water as a feed solution. In the present study, BC columns were challenged with a range of model solutions, mimicking various pretreatment options. As a result, the relative impact of dissolved organic carbon (DOC) and suspended solids (SS) on the performance of BC filters was assessed. In addition, the performance of a gravity-driven, hollow fibre ultrafiltration (UF) module was examined with regards to the potential for use as a pretreatment option. SS were observed to severely clog the columns and cause the complete cessation of flow. The subsequent removal of SS by UF improved the general filter performance as well as increasing the BC lifetime by 50 %. The UF module achieved a reduction in DOC of 34 ± 6 %, resulting in an additional 30 % increase in the lifetime of the BC column.

scholarly journals Socioeconomic Impacts of LCD-Treated Drinking Water Distribution in an Urban Community of the Kathmandu Valley, Nepal

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1323
Author(s):  
Shrestha ◽  
Kamei ◽  
Shrestha ◽  
Aihara ◽  
Bhattarai ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Distribution ◽  
Low Cost ◽  
Water Security ◽  
Control Site ◽  
Socioeconomic Impact ◽  
Kathmandu Valley ◽  
Socioeconomic Impacts ◽  
Treated Water ◽  
Treated Drinking Water

Groundwater available in the Kathmandu Valley is not suitable for drinking due to chemical and microbial contamination. We installed a treatment system, which was made with locally available materials and was low-cost, and supplied drinking water to the intervention site where groundwater contains high amounts of ammonia, iron, and turbidity. This research aims to evaluate the socioeconomic impact of treated water distribution. One hundred households were randomly selected and asked to use treated water for drinking, and another 100 households in the nearby community were taken randomly as a control. We conducted questionnaire surveys with the enrolled households before and five months after starting water distribution to assess the water use patterns and quality perceptions. The socioeconomic impact of the intervention was evaluated by a prepost comparison and by the difference-in-difference method. The intervention significantly enhanced most of the parameters of water quality perception, reduced the in-house water treatment, and improved the perceived water stress and quality of life. For the control site, these parameters generally became worse in the post-survey, which suggests that the survey might have affected people’s mindset regarding water security. The system is an option for sustainable management of drinking water in the water-scarce, hard-hit areas in the developing countries.

scholarly journals Photocatalytic Enhancement for Solar Disinfection of Water: A Review

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
J. Anthony Byrne ◽  
Pilar A. Fernandez-Ibañez ◽  
Patrick S. M. Dunlop ◽  
Dheaya M. A. Alrousan ◽  
Jeremy W. J. Hamilton
Keyword(s):  
Drinking Water ◽  
Low Cost ◽  
Waterborne Diseases ◽  
Safe Drinking Water ◽  
Developing Regions ◽  
Water Supplies ◽  
Semiconductor Photocatalysis ◽  
Solar Disinfection ◽  
Clean Drinking Water

It is estimated that 884 million people lack access to improved water supplies. Many more are forced to rely on supplies that are microbiologically unsafe, resulting in a higher risk of waterborne diseases, including typhoid, hepatitis, polio, and cholera. Due to poor sanitation and lack of clean drinking water, there are around 4 billion cases of diarrhea each year resulting in 2.2 million deaths, most of these are children under five. While conventional interventions to improve water supplies are effective, there is increasing interest in household-based interventions to produce safe drinking water at an affordable cost for developing regions. Solar disinfection (SODIS) is a simple and low cost technique used to disinfect drinking water, where water is placed in transparent containers and exposed to sunlight for 6 hours. There are a number of parameters which affect the efficacy of SODIS, including the solar irradiance, the quality of the water, and the nature of the contamination. One approach to SODIS enhancement is the use of semiconductor photocatalysis to produce highly reactive species that can destroy organic pollutants and inactivate water pathogens. This paper presents a critical review concerning semiconductor photocatalysis as a potential enhancement technology for solar disinfection of water.

scholarly journals Fabrication of potable and eco-friendly solar disinfection (sodis) unit and its performance analysis

2021 ◽  
Vol 8 (1) ◽  
pp. 41-50
Author(s):  
Malavika J P ◽  
Shobana C
Keyword(s):  
Drinking Water ◽  
Solar Energy ◽  
Water Samples ◽  
Polluted Water ◽  
Contaminated Water ◽  
Treated Water ◽  
Solar Disinfection ◽  
E Coli ◽  
Pet Bottles ◽  
Disinfection Unit

Solar disinfection (SODIS) is a technique, which involves utilization of solar energy to make safe drinking water from biologically contaminated water. In the conventional SODIS method, the PET bottles are filled with polluted water and exposed to the sunlight for a certain period depending upon the local weather conditions. However much more effective disinfection system is needed to overcome the problems of inefficient utilization of available solar energy and the health risk posed by treating the water using chemicals during the purification process.  Hence, the present work aims in designing a portable solar disinfection unit that can efficiently use solar energy by manually adjusting the unit according to sunlight availability. Along with it, incorporation of the additional eco-friendly unit with water purifying plants Vetiveria zizanioides (Vetiver) and Hemidesmus indicus (Nannari) is done to achieve high efficiency in producing potable water from biologically contaminated water. The contaminated water samples treated in the solar disinfection unit and eco-friendly water purifying unit are analyzed for the presence of total coliforms and E-coli by using the Most probable Number method and P/A analysis, respectively. A reduction in 99.74% of total coliform count and absence of E-coli was observed in the treated water samples.  The physicochemical analysis was carried out to ensure the suitability of treated water for consumption and the results revealed a notable reduction in the parameters, and all the parameters came under the permissible range of IS drinking water characteristics. The designed system can be used to disinfect the contaminated water sample most efficiently, thereby making the water suitable for consumption.

Effectiveness of solar disinfection (SODIS) in rural coastal Bangladesh

2015 ◽  
Vol 13 (4) ◽  
pp. 1113-1122 ◽  
Author(s):  
Md. Atikul Islam ◽  
Abul Kalam Azad ◽  
Md. Ali Akber ◽  
Masudur Rahman ◽  
Indrojit Sadhu
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Coastal Area ◽  
Rainwater Harvesting ◽  
Low Cost ◽  
Treatment Technology ◽  
Solar Disinfection ◽  
E Coli ◽  
Alternative Water ◽  
Alternative Water Supply

Scarcity of drinking water in the coastal area of Bangladesh compels the inhabitants to be highly dependent on alternative water supply options like rainwater harvesting system (RWHS), pond sand filter (PSF), and rain-feed ponds. Susceptibility of these alternative water supply options to microbial contamination demands a low-cost water treatment technology. This study evaluates the effectiveness of solar disinfection (SODIS) to treat drinking water from available sources in the southwest coastal area of Bangladesh. A total of 50 households from Dacope upazila in Khulna district were selected to investigate the performance of SODIS. Data were collected in two rounds to examine fecal coliform (FC) and Escherichia coli (E. coli) contamination of drinking water at the household water storage containers and SODIS bottles, and thereby determined the effectiveness of SODIS in reducing fecal contamination. All water samples were analyzed for pH, electrical conductivity, turbidity and salinity. SODIS significantly reduced FC and E. coli contamination under household conditions. The median health risk reduction by SODIS was more than 96 and 90% for pond and RWHS, respectively. Besides, turbidity of the treated water was found to be less than 5 NTU, except pond water. Only 34% of the participating households routinely adopted SODIS during the study.

scholarly journals Reduction of trihalomethane formation and detoxification of microcystins in tap water by ozonation

2008 ◽  
Vol 6 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Orapin Thapsingkaew ◽  
Vilailuck Kijjanapanich ◽  
Werawan Ruangyuttikarn
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Tap Water ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Residual Chlorine ◽  
Treated Water ◽  
Guideline Value ◽  
Phosphatase 2A ◽  
The Mean

The efficiency of ozonation in comparison to chlorination for removal of microcystins and production of trihalomethanes (THMs) in water was investigated. One hundred and ninety water samples of ozone and chlorine treated water were collected at a water treatment plant between August 2004 and March 2005. The level of THMs, total organic carbon and residual chlorine were determined. Protein phosphatase 2A inhibition assay was used to detect microcystins and the presence of microcystins was confirmed by HPLC. The results show that 91.5% of the THM species in treated water was chloroform and 8.5% was bromodichloromethane. The mean THM level± standard error of mean in chlorinated water (CW) (45.1±3.0 μg/L) was higher than the mean of THM level in ozonated water (OW) (18.6±2.2 μg/L). In addition, no OW sample exceeded the first stage U.S. EPA maximum THM contaminant level for drinking water (80 μg/L) and only 8% of these samples exceeded the second stage level (40 μg/L). On the other hand, 3% of CW samples exceeded 80 μg/L and 68% exceeded the 40 μg/L level. The microcystin level in all water samples was below the WHO guideline value (1 μg/L) for drinking water.

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