Household Water Treatment Systems Research Articles

Evaluation of household water treatment systems in terms of physicochemical and microbiological parameters, Adana Province (Turkey) example

Evaluation of household water treatment systems in terms of physicochemical and microbiological parameters, Adana Province (Turkey) example

Diversity and metallo-β-lactamase-producing genes in Pseudomonas aeruginosa strains isolated from filters of household water treatment systems

The microbiological quality of drinking water has long been a critical element in public health. Considering the high clinical relevance of Pseudomonas aeruginosa, we examined the filters of household water treatment systems for its presence and characteristics to determine the systems' efficiency in eliminating the bacteria. In total, filters of 50 household water treatment systems were examined. Microbiological and molecular methods were used for the detection and confirmation of P. aeruginosa isolates. Random Amplification of Polymorphic DNA-polymerase chain reaction (RAPD-PCR) was performed to detect similarities and differences among P. aeruginosa isolates. Combined disk (CD) method and double disk synergy test (DDST) were performed to detect metallo-beta-lactamase (MBL)-producing P. aeruginosa isolates. Finally, PCR was performed to detect MBL genes in MBL-producing strains. From the 50 analyzed systems, 76 colonies of P. aeruginosa were identified. In some systems, isolated bacteria from different filters harbored similar genetic profiles, indicating that these isolates may be able to pass through the filter and reach higher filters of the system. Phenotypic tests revealed 7 (9.2%) MBL-producing strains. Two isolates were positive for blaVIM-1, whereas one isolate was positive for blaNDM and blaIMP-1. The wide distribution of resistant phenotypes and genetic plasticity of these bacteria in household water treatment systems indicate that resistance mechanisms circulate among P. aeruginosa isolates in the environment of the filtration systems. The presence of MBL-producing genes in these systems and P. aeruginosa as a potential reservoir of these resistance genes can be a major concern for public health.

Solar disinfection potentials of aqua lens, photovoltaic and glass bottle subsequent to plant-based coagulant: for low-cost household water treatment systems

Unaffordable construction cost of conventional water treatment plant and distribution system in most developing countries makes difficult to provide safe and adequate water for all households, especially for the rural setup. Water treatment at the source can be the best alternative. Solar disinfection is one alternative among point of use treatments. In this study, aqua lens, photovoltaic box and glass bottle were used subsequent to plant coagulants to evaluate microbial reduction potentials. Laboratory- and field-based experiments were conducted from May to August 2016. The Escherichia coli, total coliforms and heterotrophic plate counts were used as indicator organisms. The result indicated that aqua lens (AL), photovoltaic box (PV) and glass bottle (GB) have high inactivation rate subsequently almost for all indicator organisms in short solar exposure time. Total coliforms were inactivated in AL (SD = 15.8 °C, R2 = 0.92) followed by PV inactivation temperature association (SD = 11.6 C, R2 = 0.90), and the GB concentrator was inactivated (SD = 10.9 °C, R2 = 0.70) at turbidity level of 3.41 NTU. As the study indicated, aqua lens coupled with Moringa oleifera coagulant can be an effective with minimum cost for household water treatment system. The study also concludes heterotrophic bacteria were more resistant than other types of bacteria in SODIS with similar exposure time.

Effects of a behavior change campaign on household drinking water disinfection in the Lake Chad basin using the RANAS approach

Worldwide, an estimated 700 million people rely on unimproved drinking water sources; even more consume water that is not safe to drink. Inadequate drinking water quality constitutes a major risk factor for cholera and other diarrheal diseases around the globe, especially for young children in developing countries. Household water treatment and safe storage systems represent an intermediate solution for settings that lack infrastructure supplying safe drinking water. However, the correct and consistent usage of such treatment technologies rely almost exclusively on the consumer's behavior.This study targeted at evaluating effects of a behavior change campaign promoting the uptake of household drinking water chlorination in communities along the Chari and Logone rivers in Chad. The campaign was based on formative research using health psychological theory and targeted several behavioral factors identified as relevant. A total of 220 primary caregivers were interviewed concerning their household water treatment practices and mindset related to water treatment six months after the campaign. The Risks, Attitudes, Norms, Abilities, and Self-regulation (RANAS) model was used to structure the interviews as the RANAS approach had been used for designing the campaign.Results show significantly higher self-reported drinking water chlorination among participants of the intervention. Significant differences from a control group were identified regarding several behavioral factors. Mediation analysis revealed that the intervention positively affected participants' individual risk estimation for diarrheal disease, health knowledge, perceived efforts and benefits of water treatment, social support strategies, knowledge of how to perform chlorination, and perceived ability to do so. The campaign's effect on water treatment was mainly mediated through differences in health knowledge, changes in norms, and self-efficacy convictions.The findings imply that water treatment behavior can be successfully promoted using health psychological theory. However, they also indicate opportunities for improvement in the campaign design and implementation.

Performance evaluation of household water treatment systems used in Kerman for removal of cations and anions from drinking water

Increased awareness in society of the consequences of contaminants in drinking water has created a demand for household water treatment systems, which provide higher quality water, to spread. The aim of this study was to evaluate the performance of household water treatment systems used in Kerman for the removal of cations and anions. Various brands of home water treatment devices commonly used in Kerman were selected, with one device chosen from each brand for study. In cases in which the devices were used extensively, samples were selected with filters that had been changed in proper time, based on the device’s operational instructions. The samples were selected from homes in the center and four geographical directions of Kerman. Then, sampling was conducted in three stages of input and output water of each device. For each of the samples, parameters were measured, such as chloride, sulfate, bicarbonate, calcium, magnesium, hardness, sodium, nitrate and nitrite (mg/L), temperature (°C), and pH. The average removal efficiency of different parameters by 14 brands in Kerman, which include chloride ions, sulfate, bicarbonate, calcium, magnesium, sodium, nitrites, nitrates, and total hardness, was obtained at 68.48, 85, 67, 61.21, 78.97, 80.24, 32.59, 66.83, and 69.38%, respectively. The amount of sulfate, bicarbonate, chloride, calcium, magnesium, hardness, sodium, and nitrate in the output water of household water treatment systems was less than the input water of these devices, but nitrite concentration in the output of some devices was more than the input water and showed a significant difference (p > 0.05).

User preferences and willingness to pay for safe drinking water: Experimental evidence from rural Tanzania

Almost half of all deaths from drinking microbiologically unsafe water occur in Sub-Saharan Africa. Household water treatment and safe storage (HWTS) systems, when consistently used, can provide safer drinking water and improve health. Social marketing to increase adoption and use of HWTS depends both on the prices of and preferences for these systems. This study included 556 households from rural Tanzania across two low-income districts with low-quality water sources. Over 9 months in 2012 and 2013, we experimentally evaluated consumer preferences for six “low-cost” HWTS options, including boiling, through an ordinal ranking protocol. We estimated consumers’ willingness to pay (WTP) for these options, using a modified auction. We allowed respondents to pay for the durable HWTS systems with cash, chickens or mobile money; a significant minority chose chickens as payment. Overall, our participants favored boiling, the ceramic pot filter and, where water was turbid, PuR™ (a combined flocculant-disinfectant). The revealed WTP for all products was far below retail prices, indicating that significant scale-up may need significant subsidies. Our work will inform programs and policies aimed at scaling up HWTS to improve the health of resource-constrained communities that must rely on poor-quality, and sometimes turbid, drinking water sources.

Household water treatment and safe storage – effectiveness and economics

Abstract. Household Water Treatment and safe Storage (HWTS) systems aim to provide safe drinking water in an affordable manner to users where safe piped water supply is either not feasible or not reliable. In this study the effectiveness, economic parameters and costs of three selected HWTS systems were identified. The selected systems are SODIS, ceramic filter and biosand filter. These options were selected based on their accessibility, affordability and available scientific data. Data was obtained through peer-reviewed literature, reports, web-pages and informal sources. The findings show a wide dispersion for log removal of effectiveness of the HWTS systems. For bacteria (E. coli), log removals of 1–9 (SODIS), 0.5–7.2 (ceramic) and 0–3 (biosand) were reported. In the case of viruses (mostly echovirus and bacteriophages), log removals of 0–4.3 (SODIS), 0.09–2.4 (ceramic) and 0–7 (biosand) were found. The dispersions of log removals for both bacteria and viruses range from non-protective to highly protective according to WHO performance targets. The reported costs of HWTS systems show a wide range as well. The price per cubic meter water is found to be EUR 0–8 (SODIS), EUR 0.37–6.4 (ceramic) and EUR 0.08–12.3 (biosand). The retail prices found are: negligible (SODIS), USD 1.9–30 (ceramic) and USD 7–100 (biosand). No relationship was observed between removal efficiency and economics of the three systems.

Field efficacy evaluation and post-treatment contamination risk assessment of an ultraviolet disinfection and safe storage system

Inconsistent use of household water treatment and safe storage (HWTS) systems reduces their potential health benefits. Ultraviolet (UV) disinfection is more convenient than some existing HWTS systems, but it does not provide post-treatment residual disinfectant, which could leave drinking water vulnerable to recontamination. In this paper, using as-treated analyses, we report on the field efficacy of a UV disinfection system at improving household drinking water quality in rural Mexico. We further assess the risk of post-treatment contamination from the UV system, and develop a process-based model to better understand household risk factors for recontamination. This study was part of a larger cluster-randomized stepped wedge trial, and the results complement previously published population-level results of the intervention on diarrheal prevalence and water quality. Based on the presence of Escherichia coli (proportion of households with ≥1 E. coli/100 mL), we estimated a risk difference of −28.0% (95% confidence interval (CI): −33.9%, −22.1%) when comparing intervention to control households; −38.6% (CI: −48.9%, −28.2%) when comparing post- and pre-intervention results; and −37.1% (CI: −45.2%, −28.9%) when comparing UV disinfected water to alternatives within the household. We found substantial increases in post-treatment E. coli contamination when comparing samples from the UV system effluent (5.0%) to samples taken from the storage container (21.1%) and drinking glasses (26.0%). We found that improved household infrastructure, additional extractions from the storage container, additional time from when the storage container was filled, and increased experience of the UV system operator were associated with reductions in post-treatment contamination. Our results suggest that the UV system is efficacious at improving household water quality when used as intended. Promoting safe storage habits is essential for an effective UV system dissemination. The drinking glass appears to represent a small but significant source of recontamination that is likely to impact all HWTS systems.

Assessment of the impact of water parameters on the flow rate of ceramic pot filters in a long-term experiment

Poor water quality is a major contributing factor to disease in developing countries. Silver-coated ceramic pot filters (CPFs) are a relatively common form of household water treatment system (HWTS) representing an effective and sustainable technology for poor communities. Water production seems to be the major limiting factor of the CPF's lifetime and sustainability since low flow rates do not produce an adequate daily volume of treated water. This paper describes a long-term study of CPF flow rates under controlled conditions using three different water sources. The relationship between water characteristics and flow rate was assessed with the intent of identifying the principal parameters that impact CPF water production. The study concluded that turbidity seems to be the principal indicator in determining CPF lifetime in terms of quantity of treated water. There is no evidence that biological activity also contributes to premature failure of CPFs and the data did not indicate that chemical precipitation is responsible for the filter clogging. Manufacturers commonly conduct initial flow rate tests using clear water as a measure of quality assurance. However, the relationship between initial flow rate and average flow rate during the lifetime of the CPF should be further studied.

Removal of microbes to World Health Organization requirements using a locally developed, low cost, micro-porous, ceramic water filter

The quality of drinking water can no longer be taken for granted and has been the subject of tremendous attention from pressure groups and the media due to poor service delivery in South Africa. Furthermore, many of the older water treatment plants are incapable of effectively reducing microbes to safe levels. Unfortunately there are various definitions of ‘safe’. The South African government considers 10 or less viable Cryptosporidium oocysts an infective dose, while the USA and UK governments believe that one viable Cryptosporidium oocyst is an infective dose. To add to the confusion the World Health Organization recommends above 99.99% microbial reduction as safe. In Africa it really depends on how compromised your immune system is and age and nutritional level at the time of consumption of contaminated water. How can anyone protect themselves from consuming water contaminated with pathogenic microorganisms? The ceramic filter offers the poor a simple, effective and economical way of producing potable water. We report on the successful testing of a low-cost, locally produced ceramic filter (OUTBAC) with removal efficiencies in excess of 99.99% that therefore meets the World Health Organization household water treatment system criterion for safe water for a family of five at an affordable cost per year.

Efficiency of locally available filter media on fluoride and phosphate removal for household water treatment system

Since conventional water treatment is not affordable in developing countries, looking for locally available and alternative treatment options is mandatory. Removal of fluoride and phosphate can be achieved by designing appropriate filtration media from different materials such as sand, calcined clay, pumice, scoria and bone char. This study was designed to determine the removal efficiency of these locally available filter media with respect to detention time and pH. The filtration apparatuses (tank) were filled separately with stone, gravel with grain size 0.6–4.75 mm and 40 cm deep, sand (ES = 0.15–0.35 mm and UC = 1.5–3), calcined clay, pumice, scoria and bone char with grain size 0.25–0.5 inch. Water samples were prepared using glass bottles with fluoride concentrations of 6 and 8 mg/l and phosphate concentration of 4 mg/l. Laboratory analysis was carried out before and after filtration to determine the removal efficiency of each medium. It was found that the highest removal of fluoride was achieved by...

Factors involved in sustained use of point-of-use water disinfection methods: a field study from Flores Island, Indonesia.

Many scientific studies have suggested that point-of-use water treatment can improve water quality and reduce the risk of infectious diseases. Despite the ease of use and relatively low cost of such methods, experience shows the potential benefits derived from provision of such systems depend on recipients' acceptance of the technology and its sustained use. To date, few contributions have addressed the problem of user experience in the post-implementation phase. This can diagnose challenges, which undermine system longevity and its sustained use. A qualitative evaluation of two household water treatment systems, solar disinfection (SODIS) and chlorine tablets (Aquatabs), in three villages was conducted by using a diagnostic tool focusing on technology performance and experience. Cross-sectional surveys and in-depth interviews were used to investigate perceptions of involved stakeholders (users, implementers and local government). Results prove that economic and functional factors were significant in using SODIS, whilst perceptions of economic, taste and odour components were important in Aquatabs use. Conclusions relate to closing the gap between factors that technology implementers and users perceive as key to the sustained deployment of point-of-use disinfection technologies.

Bacteria and virus removal effectiveness of ceramic pot filters with different silver applications in a long term experiment

In 2012 more than 4 million people used a ceramic pot filter (CPF) as household water treatment system for their daily drinking water needs. In the normal production protocol most low cost filters are impregnated with a silver solution to enhance the microbial removal efficiency. The aim of this study was to determine the role of silver during the filtration and subsequent storage. Twenty-two CPFs with three different silver applications (non, only outside and both sides) were compared in a long-term loading experiment with Escherichia coli (K12 and WR1) and MS2 bacteriophages in natural challenge water under highly controlled laboratory circumstances. No significant difference in Log Removal Values were found between the filters with different silver applications. The results show that the storage time in the receptacle is the dominant parameter to reach E. coli inactivation by silver, and not the contact time during the filtration phase. The hypothesis that the absence of silver would enhance the virus removal, due to biofilm formation on the ceramic filter element, could not be confirmed. The removal effectiveness for viruses is still of major concern for the CPF. This study suggests that the ceramic pot filter characteristics, such as burnt material content, do not determine E. coli removal efficacies, but rather the contact time with silver during storage is the dominant parameter to reach E. coli inactivation.

Household survey of installation and treatment efficiency of point-of-use water treatment systems in Hanoi, Vietnam

Since urban water supply is not yet available for every inhabitant in Hanoi City, numerous residents look for alternative sources such as groundwater and rainwater to compensate the supply shortage. However, in parts of Hanoi, it was reported that groundwater is polluted by various contaminants including arsenic (As) and ammonia (NH 4 -N). Therefore, numerous types of point-of-use (POU) water treatment systems have been used in households, but treatment efficiency has not been well documented. Hence, this study aims to investigate the proliferation and efficiency of household treatment systems. One hundred and seventy households from three communes were selected for a survey of questionnaires and face-to-face interviews. Twenty-four household water treatment systems from six communes were monitored for water sample collection and analysis. The results indicate that sand filter (SF), ceramic filter (CF), microfiltration (MF), anion exchange (AX) and reverse osmosis (RO) were popular POU water treatment systems, but removal efficiency varied among different treatment processes. Groundwater quality shows an average As concentration of 71 μg/L (max. 305 μg/L) and 81% of these samples had As concentration higher than the World Health Organization guideline value of 10 μg/L. An integration of SF and RO can guarantee water with As concentration below 10 μg/L, whereas AX, MF and CF did not remove As at all.

Rainwater and greywater harvesting for urban food security in La Soukra, Tunisia

This paper presents the findings of an integrated household water treatment and reuse system for agriculture in La Soukra, Tunisia. The researchers found that the system has an internal rate of return of 17% and a net present value range from USD 26,000 (at a 5% discount rate) to USD 11,000 (for a 10% discount rate). Benefits included more water for irrigation, reduced costs to service providers, increased agricultural production from greenhouses and expanded agricultural options. These results suggest that investments in rainwater harvesting and greywater treatment at the farm level can increase the financial feasibility of peri-urban farms, which are often faced with pressure from urban growth. The systems can also help build household resilience to broader environmental change by lowering the exposure of farmers to burdens associated with infrequent access to water and poor-quality soil.

Removal of selected microorganisms using silver-impregnated and coated, low-cost, micro-porous, ceramic water filters

There is great need to purify the contaminated water which the poor people in Africa have access to, and make it safe for drinking in a way that is affordable and effective. A particular challenge is the removal of pathogenic bacteria and viruses, which traditionally are eliminated by expensive nano-filtration or reverse osmosis. An added requirement is satisfying the recent recommendation of the WHO for household water-treatment systems to eliminate 99.99% of microbial contamination, which is proving exceptionally difficult to achieve in poor countries at a cost they can afford. We report on the successful testing of a low-cost, locally produced ceramic filter that has the potential to meet the WHO criterion at a cost of US$10 per year. In one version the filter consisted of a silver-impregnated, highly porous ceramic; in another modification silver nano particles were incorporated on the ceramic surface. The silver-impregnated filter was tested on water samples contaminated with selected Gram negative bacteria: Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa, for its oligodynamic effect and for its effective reduction of bacteriophages. The ceramic filters reduced the viral count by 94–99% and we believe that, with further development, our prototype is easily capable of achieving the WHO criterion.

Removal of waterborne bacteria from surface water and groundwater by cost-effective household water treatment systems (HWTS): A sustainable solution for improving water quality in rural communities of Africa

In this study 5 household water-treatment devices/systems (HWTS) were constructed using inexpensive local materials (sand, gravel, zeolites and clays). They included the silver-impregnated porous pot filter (SIPP), the ceramic candle filter (CCF), the conventional biosand filter (BSF-S), a modified biosand filter with zeolites (BSF-Z), and a bucket filter (BF).Their ability to remove turbidity and pathogenic bacteria (Vibrio cholerae, Salmonella typhimurium and Shigella dysenteriae) from synthetic sterile water, groundwater and surface-water sources was evaluated. The flow rates ranged from 0.05 ℓ·h-1 to 2.49 ℓ·h-1 for SIPP; 1 ℓ·h-1 to 4 ℓ·h-1 for CCF; 0.81 ℓ·h-1 to 6.84 ℓ·h-1 for BSF-S; 1.74 ℓ·h-1 to 19.2 ℓ·h-1 for BSF-Z; and from 106.5 ℓ·h-1 to 160.5 ℓ·h-1 for BF. The highest (64% to 98% (0.74 to 1.08 NTU)) and lowest (14% to 76% (2.91 to 7.19 NTU)) average percentage turbidity removals were noted for SIPP and BF, respectively. The SIPP was the only device that consistently removed 100% of all target pathogens throughout the study. Its performance was found to be significantly superior (p<0.05) compared to that of the other four devices. Sixty (60%) to 100% bacterial removals were observed for BSF-S; 90% to 100% for BSF-Z; 90% to 100% for CCF; and 40% to 99.9% for BF. Based on the findings of this study the SIPP can be recommended for use by rural communities as it consistently produced high-quality water that complied with the SANS 241 turbidity and microbiological limits for drinking water.Keywords: safe drinking water, household water treatment, waterborne pathogens

Achieving long-term use of solar water disinfection in Zimbabwe

To use a psychological theory of behavioural change to measure and interpret the effectiveness of different promotional strategies for achieving long-term usage of a household water treatment and safe storage (HWTS) system in peri-urban Zimbabwe. Solar disinfection (SODIS) was introduced into five peri-urban communities near Harare, Zimbabwe. Six different interventions were developed and were applied in four communities in different combinations, with the fifth remaining as a control area where no interventions were implemented. Throughout the 26 months of the study nine longitudinal panel surveys were conducted in which SODIS usage was estimated using three separate metrics: reported, calculated, and observed. A total of 1551 people were interviewed. The three indicators of SODIS usage broadly agreed with one another. By any measure, the most effective intervention was household visits by trained promoters in combination with persuasion. Households which received household visits maintained SODIS usage rates of 65% or more, even six months after the cessation of all promotional activities. Households receiving other interventions were significantly less effective. Interventions like prompts or public commitment after the application of household visits were effective at maintaining good practices once these were established. Household promotion in combination with persuasion appears more effective than other approaches, especially when followed with interventions targeting the maintenance of the new behaviour. With this intervention it is possible that around 65% of the households continue to use solar water disinfection (SODIS) more than two years after the initial promotion, and six months after the end of all interventions.

The Low Cost High Value Ceramic Colloidal Silver Filter: Household Water Treatment System

No AbstractDOI: http://dx.doi.org/10.3126/hn.v9i0.7078 Hydro Nepal Vol.9 July 2011 71

Risk reduction assessment of waterborne Salmonella and Vibrio by a chlorine contact disinfectant point-of-use device

Unsafe drinking water continues to burden developing countries despite improvements in clean water delivery and sanitation, in response to Millennium Development Goal 7. Salmonella serotype Typhi and Vibrio cholerae bacteria can contaminate drinking water, causing waterborne typhoid fever and cholera, respectively. Household water treatment (HWT) systems are widely promoted to consumers in developing countries but it is difficult to establish their benefits to the population for specific disease reduction. This research uses a laboratory assessment of halogenated chlorine beads treating contaminated water to inform a quantitative microbial risk assessment (QMRA) of S. Typhi and V. cholerae disease in a developing country community of 1000 people. Laboratory challenges using seeded well water resulted in log10 reductions of 5.44 (± 0.98 standard error (SE)) and 6.07 (± 0.09 SE) for Salmonella serotype Typhimurium and V. cholerae, respectively. In well water with 10% sewage and seeded bacteria, the log10 reductions were 6.06 (± 0.62 SE) and 7.78 (± 0.11 SE) for S. Typhimurium and V. cholerae, respectively. When one infected individual was contributing to the water contamination through fecal material leaking into the water source, the risk of disease associated with drinking untreated water was high according to a Monte Carlo analysis: a median of 0.20 (interquartile range [IQR] 0.017-0.54) for typhoid fever and a median of 0.11 (IQR 0.039-0.20) for cholera. If water was treated, risk greatly decreased, to a median of 4.1 × 10(-7) (IQR 1.6 × 10(-8) to 1.1 × 10(-5)) for typhoid fever and a median of 3.5 × 10(-9) (IQR 8.0 × 10(-10) to 1.3 × 10(-8)) for cholera. Insights on risk management policies and strategies for public health workers were gained using a simple QMRA scenario informed by laboratory assessment of HWT.