Comparative study of disinfectants for use in low-cost gravity driven household water purifiers (original) (raw)
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International Journal for Service Learning in Engineering, Humanitarian Engineering and Social Entrepreneurship
Point of Use (POU) drinking water treatment shows potential to save the lives of thousands who die every day from preventable waterborne illnesses. Most POU treatment focuses on either household scale filtration or community-level disinfection, but there remains a need for a low-cost batch treatment system incorporating both filtration and disinfection. Consequently, a drinking water treatment system including sand filtration and locally-generated chemical disinfection was constructed from inexpensive and accessible materials. The prototype consisted of two barrels and a circulation pump, with water cycling through a gravity sand filter before being injected with chlorine produced through saline electrolysis. The treatment efficacy of the prototype was determined by turbidity reduction and disinfection effectiveness. Ninety gallons of surface water displayed a 70% reduction in turbidity after ninety minutes of operation, and no coliform bacteria were detected in the system upon completion of treatment. The purchase cost of the system components was less than 900(2017)andthetotalprojectdisplaysanestimatednetpresentvalueof(900 (2017) and the total project displays an estimated net present value of (900(2017)andthetotalprojectdisplaysanestimatednetpresentvalueof(4,100) over 10 years. The system is safe, simple, and reliable, and could be foundational to the development and implementation of chemical disinfection in batch filtration processes for POU water treatment.
Development and evaluation of a small scale water disinfection system
Journal of Water, Sanitation and Hygiene for Development, 2016
Provision of microbiologically safe drinking water for people living in the rural areas of developing countries remains a major challenge to date. A simple gravity-driven membrane point of use system was developed based on woven fabric microfiltration (WFMF) membranes. The WFMF is a loose type of membrane (0.45 μm). However, complete disinfection is not achieved with the WFMF, hence it was incorporated with two disinfectants. This study aimed to combine the WFMF with two disinfectants (WaterGuard and bromochlor tablets) to bring the water to the accepted quality for drinking. Four different types of water were sourced, considering two factors: E. coli and turbidity content. The WFMF demonstrated excellent filtration performance by producing permeates with turbidity less than 1 NTU for feed turbidity ranging between 10 and 200 NTU. There was 95–99.8% E. coli removal for raw feeds with influent E. coli ranging between 500 and 44,500 CFU/100 mL. Total disinfection was achieved with both...
BROWNELL 2008 Assessment of a low cost water disinfection technology.doc
2008
We describe a point-of-use (POU) ultraviolet (UV) disinfection technology, the UV Tube, which can be made with locally available resources around the world for under $50 US. Laboratory and field studies were conducted to characterize the UV Tube’s performance when treating a flowrate of 5 L/min. Based on biological assays with MS2 coliphage, the UV Tube delivered an average fluence of 900 ^ 80 J/m2 (95% CI) in water with an absorption coefficient of 0.01 cm21 . The residence time distribution in the UV Tube was characterized as plug flow with dispersion (Peclet Number ¼ 19.7) and a mean hydraulic residence time of 36 s. Undesirable compounds were leached or produced from UV Tubes constructed with unlined ABS, PVC, or a galvanized steel liner. Lining the PVC pipe with stainless steel, however, prevented production of regulated halogenated organics. A small field study in two rural communities in Baja California Sur demonstrated that the UV Tube reduced E. coli concentrations to less than 1/100 ml in 65 out of 70 samples. Based on these results, we conclude that the UV Tube is a promising technology for treating household drinking water at the point of use.
Disinfection of Water: Review on Research towards Effective and Economical Alternatives
http://ijshr.com/IJSHR\_Vol.2\_Issue.1\_Jan2017/IJSHR001.pdf, 2017
The water consumption in chemical, pharmaceutical and construction activities constitutes sizeable amount out of total water consumption. The reuse and recycle of industrial wastewater needs to be effectively carried out. Disinfection of water used for domestic and potable purposes is still a challenge for developing and under developed countries. Disinfection of water can be done physical, chemical and biological methods. Recycle and reuse of wastewater can be carried out by treating the wastewater and further using advanced treatment methods like membrane separation, electro-dialysis and pervaporation. Maintaining water quality in water distribution system is one of the major problems in developing countries.
Efficiency of Water-Purifying devices used in homes and industries
The use of water-purifying devices are gaining popularity, as many homes and industries are using them to treat water for dinking. However, most of the users do not know much about the performance/efficiency of these devices, hence this investigation. Efficiency of water-purifying devices were evaluated to determine their efficiencies in treating water consumed by people. Raw water samples from groundwater source, borehole (a major source of drinking water) in Owerri, Nigeria were treated using commonly used water treatment devices: resin ion-exchanger, sand-bed filter, activated carbon filter, micron filter, reverse osmosis membrane filter, ozonator, and UV-sterilizer. The resulting purified water samples were labeled, and each were subjected to physical, chemical and bacteriological analyses using APHA (2006) water analysis method. Raw water (control) sample had pH value of 6.7 while the pH values of treated water samples fell within 6.9 – 7.1. Turbidity value of control sample was 6.0 NTU with other samples recording 4.0 NTU and below. Total heterotophic bacteria count and total coliforms counts of the raw water sample were 4.0 x 10 2 CFU/ml and 2.2 x 10 2 CFU/100ml respectively, but were below 2.5 x 10 2 CFU/ml and 1.9 x 10 2 CFU/100ml respectively in some of the treated samples, and nil in others. The overall efficiency of the treatment devices were of the order: Reverse osmosis membrane filter (76.25%) > UV-sterilizer (72.24%) > micron filter (65.85%) > Ozonator (62.97%) > Activated carbon filter (51.86%) > Resin ion-exchanger (46.67%) > Sand-bed filter (43.55%). This implies that not all water treatment devices used in homes and indutries are efficient enough to yield qualitative drinking water for unsuspecting users.
Controlling Assessment of Disinfection by Products in Drinking Water – A Review
2015
The treatment and distribution of drinking water for a safe use is one of the greatest achievements of our twentieth century. Drinking water disinfection and treatment is the most successful measurement to reduce water born and bacteria that cause many disease and it is the most effective way to protect health. Before the beginning of drinking water treatment and disinfection history, many diseases had been killed thousands of people around the world and until now many people around the world have no appropriate access to clean drinking water. According to World Health Organization (WHO), in 2012, 748 million people still relied on unimproved drinking water source. It is known that water disinfection is very important and inescapable step in water treatment process to ensure safe drinking water that is leads to the formation of disinfection-by products (DBPs). Many disinfections by products are detected in drinking water, and they are usually grouped into the following categories: Trihalomethans (THMs), Haloacetic acid (HAAS) Inorganic disinfections by-products (bromate and chlorite).
Household Scale Clean Water Disinfection Technique with Chlorination Method
Abstract- Disinfection is preventive efforts against the entry of pathogenic bacteria to the human body. Chlorination is one effort to give prevention with chlorine. The research objective was to determine of diffusion and mass transfer coefficients and then to develop of a chlorinated tool model. Effect of water flow rate on chlorine transport and granule size was studied to develop their relationship. The flow rates discharge used were 8 liters/minute, 14 liters/minute, and 20 liters/minute, whereas the granule sizes were 2.36 – 4.75 ml, 4.75-9.5 ml, and 9.5 - 16 ml. Diffusion coefficients and mass transfer determined by least summed of square of error. Diffusion coefficient and mass transfer used for disinfection technique was 0.4371 cm2 minute-1 and 0.0039-minute-1, as well as flow rate and granule size used was 9.5 ml - 16 ml and 8 liters/minute. Experiment testing of chlorination performed to ensure of them was potentially for chlorination. Raw water chlorinated then was found of free chlorine residual and the total coliform met the quality standards based on regulation the Ministry of Health of Republic of Indonesia’s number 416 of 1990 about the terms of supervision and the quality of water.
Water Research, 1997
Abstraet-A point-of-use (POU) water treatment system (WTS), comprised of a pressed activated carbon block filter followed by an ultraviolet (UV) light reactor, was evaluated for microbial disinfection efficacy following the general guidelines of the United States Environmental Protection Agency Guide Standard and Protocol for Testing Microbiological Water Purifiers. The POU WTS was challenged against bacterial, viral and protozoan waterborne pathogens including Vibrio cholerae, Shigella dysenteriae serotype 2, Escherichia coli 0157:H7, Salmonella typhi, hepatitis A virus strain HM 175, poliovirus type i strain Lsc2ab, simian rotavirus SAIl, Cryptosporidium parvum oocysts, Giardia lamblia cysts and coliphage MS2. The POU WTS was tested for the removal/inactivation of each challenge organism in separate 16-to 20-day test periods under various conditions of water quality, at the system's maximum recommended flow rate and at 70% of the lamps normal UV intensity. For each organism tested, microbial challenges were conducted over the course of the test period at 0, 50, 100 and 150% of the system manufacturer's rated water treatment capacity. Each microbial challenge consisted of 30 L of influent water containing approximately 105 bacterial cfu/mL, 104 viral pfu/mL or 103 protozoan cysts/mL. Influent and effluent water samples were taken during the challenges and assayed for the particular pathogen and the percent reduction calculated. Effluent water samples were also taken and assayed for the possible presence of the pathogens following two 60-h stagnation periods. The POU WTS was found to effectively remove and/or inactivate greater than 99.9999% of the bacterial pathogens, greater than 99.99% of the viruses and greater than 99.9% of the protozoan cysts and oocysts tested to 150% of the water treatment capacity of the POU WTS. These findings suggest that a properly designed and operated POU WTS may be a practical approach to removing microbiological waterborne pathogens from drinking water.
Sachet-type point-of-use (POU) water treatment product comparison for emergencies
2013
Point-of-use (POU) water treatment and safe storage techniques are effective in improving microbial water quality and decreasing diarrhoeal disease incidence and have potential to be effective interventions in humanitarian emergency contexts. Coagulant/disinfection products (CDPs) can provide microbial quality improvement, turbidity reductions, and a protective post-treatment free chlorine residual. The objective of this study was to compare the treatment performance of 4 commercially-available CDPs with regards to humanitarian water treatment objectives. This is the first comparison of its kind it was demonstrated the (at times significant) inter- and intra-variability of CDP treatment performance between products and with regards to varying water quality, respectively. It is recommended that implementing agencies should conduct field testing for context specific assessments of product performance and acceptability by beneficiaries. Knowledge of product formulation can also help in...
A compact point-of-use water purification cartridge for household use in developing countries
Simple, low-cost household interventions are known to be effective in lowering the incidence of waterborne diseases in developing countries. However, high costs along with operational and maintenance issues have prevented the successful adoption of these interventions among the affected communities. To address these limitations, a cost-effective, gravity-driven water purification cartridge has been developed by employing the synergistic disinfection action of low concentrations of silver and chlorine on bacteria and viruses. The silver and chlorine treatment components within the cartridge have been developed using inexpensive materials and integrated with a life indicator and auto-shut-off-mechanism within a compact form factor. The antibacterial as well as antiviral performance of the cartridge was tested by using ground water spiked with Escherichia coli and MS2 bacteriophage. The results show that, although individually, the silver and chlorine treatment systems were unable to inactivate the test strains, the integrated cartridge inactivates both bacteria as well as viruses up to the log reduction requirement of the USEPA guide standard for microbiological water purifiers over its designated life of 2,000 liters.