A novel low-cost multi-barrier system for drinking water treatment in rural and suburban areas

2019 ◽  
Vol 15 (1) ◽  
pp. 48-65 ◽  
Author(s):  
Stephen Siwila ◽  
Isobel C. Brink
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Granular Media ◽  
Low Cost ◽  
Water System ◽  
Drinking Water Treatment ◽  
Fecal Coliforms ◽  
E Coli ◽  
Suburban Areas ◽  
Novel Concept

Abstract A low-cost multi-barrier drinking water system incorporating geotextile fabric for pre-filtration, silver-coated ceramic granular media (SCCGM) for filtration and disinfection, granular activated carbon (GAC) as an adsorption media and a safe storage compartment for treated water has been developed and tested. The developed system offers a novel concept of point-of-use drinking water treatment in rural and suburban areas of developing countries. The system is primarily aimed at bacterial and aesthetic improvement and has been optimised to produce >99.99% E. coli and fecal coliforms removal. Although particular emphasis was placed on the elimination of bacteria, improvement of the acceptability aspects of water was also given high priority so that users are not motivated to use more appealing but potentially unsafe sources. This paper discusses key system features and contaminant removal performance. A system using SCCGM only was also tested alongside the multi-barrier system. Strengths and weaknesses of the system are also presented. Both the developed and SCCGM-only systems consistently provided >99.99% E. coli and fecal coliforms removal at an optimum flow of 2 L/h. The developed system significantly recorded improvements of aesthetic aspects (turbidity, color, taste and odor). Average turbidity removals were 99.2% and 90.2% by the multi-barrier and SCCGM-only systems respectively.

Occurrence of pathogenic microorganisms in the Saint Lawrence River (Canada) and comparison of health risks for populations using it as their source of drinking water

2000 ◽  
Vol 46 (6) ◽  
pp. 565-576 ◽  
Author(s):  
Pierre Payment ◽  
Aminata Berte ◽  
Michèle Prévost ◽  
Bruno Ménard ◽  
Benoît Barbeau
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Drinking Water Treatment ◽  
Fecal Coliforms ◽  
Giardia Infection ◽  
Bacterial Indicators ◽  
Treatment Practices ◽  
Water Treatment Plants ◽  
Wide Range ◽  
Annual Risk

A 300-km portion of the Saint Lawrence hydrological basin in the province of Québec (Canada) and 45 water treatment plants were studied. River water used by drinking water treatment plants was analyzed (6-L sample volumes) to determine the level of occurrence of bacterial indicators (total coliforms, fecal coliforms, and Clostridium perfringens) and pathogens (Giardia lamblia, Cryptosporidium, human enteric viruses). Pathogens and bacterial indicators were found at all sites at a wide range of values. Logistic regression analysis revealed significant correlations between the bacterial indicators and the pathogens. Physicochemical and treatment practices data were collected from most water treatment plants and used to estimate the level of removal of pathogens achieved under cold (0°C-4°C) and warm (20°C-25°C) water temperature conditions. The calculated removal values were then used to estimate the annual risk of Giardia infection using mathematical models and to compare the sites. The estimated range of probability of infection ranged from 0.75 to less than 0.0001 for the populations exposed. Given the numerous assumptions made, the model probably overestimated the annual risk, but it provided comparative data of the efficacy of the water treatment plants and thereby contributes to the protection of public health.Key words: public health, drinking water, health risk, pathogen occurrence.

Orthophosphate removal from aqueous solutions using drinking-water treatment sludge

2013 ◽  
Vol 68 (8) ◽  
pp. 1757-1762 ◽  
Author(s):  
Krzysztof Piaskowski
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Low Cost ◽  
Drinking Water Treatment ◽  
Cost Effective ◽  
Underground Water ◽  
Iron Hydroxides ◽  
Water Treatment Sludge ◽  
Main Component ◽  
Static Conditions

Drinking-water treatment sludge (DWTS) is a by-product generated during the production of drinking water where iron hydroxides are the main component of the sludge. The aim of the study presented here was to determine the effectiveness of using ferric sludge from two underground water treatment stations to remove orthophosphates from a model solution. The analyses were performed in static conditions. The sludge was dosed in a dry and suspended form. Using sludge dried at room temperature and preparing the suspension again proved to be much less effective in orthophosphate removal than using a suspension brought directly from the station. An increase in process effectiveness with a decreasing pH was observed for all the analysed sludge. Due to the low cost and high capability, DWTS has the potential to be utilised for cost-effective removal of phosphate from wastewater.

Partial demineralisation of drinking water using carbon dioxide regenerated ion exchangers

2002 ◽  
Vol 2 (1) ◽  
pp. 57-62 ◽  
Author(s):  
W.H. Höll ◽  
K. Hagen
Keyword(s):  
Carbon Dioxide ◽  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Cation Exchanger ◽  
Low Cost ◽  
Exchange Process ◽  
Drinking Water Treatment ◽  
Acidic Cation Exchanger ◽  
Ion Exchange Process

CARIX is an ion exchange process which usually applies a mixed bed consisting of a weakly acidic and a strongly basic exchanger material. Carbon dioxide is applied as the only chemical for regeneration of the exchangers. As a consequence, the effluent contains only the amount of salt eliminated during the service cycle. CARIX allows a combined partial softening/dealkalisation/sulfate/nitrate of drinking water. A modification of the process uses exclusively a weakly acidic cation exchanger and allows a softening/dealkalisation. The process has been realised for drinking water treatment in five full-scale plants in Germany. Results of operation demonstrate that an excellent water quality is provided at fairly low cost.

scholarly journals A comparison of DNA repair and survival of Escherichia coli O157:H7 following exposure to both low- and medium-pressure UV irradiation

2007 ◽  
Vol 5 (3) ◽  
pp. 407-415 ◽  
Author(s):  
J. L. Zimmer-Thomas ◽  
R. M. Slawson ◽  
P. M. Huck
Keyword(s):  
Dna Repair ◽  
Drinking Water ◽  
Water Treatment ◽  
Uv Irradiation ◽  
Drinking Water Treatment ◽  
Uv Exposure ◽  
E Coli ◽  
Medium Pressure ◽  
Treatment Conditions ◽  
Low Levels

DNA repair and survival of pathogenic E. coli O157:H7 was investigated following exposure to ultraviolet (UV) radiation from both low-pressure (LP) and medium-pressure (MP) lamps. This study included irradiation at UV doses used in drinking water treatment and lower doses indicative of potential treatment problems. Immediately following UV exposure, an average log inactivation of 4.5 or greater was observed following all tested doses of LP (5, 8, 20 and 40 mJ/cm2) or MP UV (5 and 8 mJ/cm2) indicating the sensitivity of E. coli O157:H7 to UV irradiation. Following conditions conducive to repair, maximum photo repair occurred rapidly within 30 minutes after low doses (5 and 8 mJ/cm2) of LP UV. The rate of repair was much higher than reported previously in non-pathogenic E. coli (which occurred within 2 hours). In contrast to LP UV, limited photo repair of E. coli O157:H7 was observed following MP UV exposure at reduced doses (5 and 8 mJ/cm2). At these lower doses, low levels of light independant repair were observed following LP UV, but not following exposure of MP UV irradiation. This study indicates that MP UV may enhance UV disinfection of E. coli O157:H7 by reducing the ability to repair following non-ideal treatment conditions. Following doses used in drinking water treatment (20 and 40 mJ/cm2), low levels of photo repair following LP UV were evident.

scholarly journals Evaluation of high rate sedimentation lab-scale tank performance in drinking water treatment

2018 ◽  
pp. 9-15
Author(s):  
Claudia Patricia Vesga-Rodríguez ◽  
Leonardo David Donado-Garzón ◽  
Monroe Weber-Shirk
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Potable Water ◽  
Low Cost ◽  
Drinking Water Treatment ◽  
High Rate ◽  
Upward Flow ◽  
Cornell University ◽  
Energy Dependent ◽  
Potable Water Treatment

The Cornell University AguaClara program researches ways to improve the process of potable water treatment at low cost and no energy dependent. A High Rate  Sedimentation (HRS) process that uses upward flow and less area than traditional tanks was investigated. The objective was to analyze parameters affecting HRS tank performance including velocity, density of the floc blanket and location of plate settlers in a laboratory scale HRS tank. Different velocities were set during the experiment, and the resulting performance of the floc blanket was evaluated through continuous turbidity measurements. Results demonstrated that the lab-scale tank allows the creation of a floc blanket and is a versatile design with constraints of visibility and accessibility. In addition, performance of the sedimentation tank improves at lower up flow velocities; however, the study suggests that plate settlers at the top of the tank stabilized the floc blanket at higher velocities, as a consequence of denser floc blankets created by the plates.

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