Gravity-driven multifunctional microporous membranes for household water treatment: Simultaneous pathogenic disinfection, metal recycling, and biofouling mitigation

2021 ◽  
Vol 410 ◽  
pp. 128289
Author(s):  
Shu Xu ◽  
Dongwei Lu ◽  
Jingyao Qi ◽  
Panpan Wang ◽  
Yumeng Zhao ◽  
...  
2020 ◽  
Vol 20 (3) ◽  
pp. 837-850
Author(s):  
Jonghun Lee ◽  
Kwang Pyo Son ◽  
Pyung-Kyu Park ◽  
Soo Hong Noh

Abstract Various types of gravity-driven membrane (GDM) systems have been developed to solve household water treatment problems. A gravity-driven free-end membrane (E-GDM) system was developed to mitigate the deposition of cake on the membrane more effectively than other commercialized GDM systems. The E-GDM system was manually operated with permeability of 12.94 and 1.75 L/m2/h/kPa for a kaolin suspension and a wastewater treatment plant influent sample, respectively, showing the highest average permeability and flow rate among all GDM systems. The GDM systems tested in this study met the daily minimum water requirement of a five-person family, except for a case in which wastewater treatment plant influent is filtered using a commercialized GDM system. According to permeability data from an accelerated cleaning test, the E-GDM system can be expected to guarantee 79,858 L of safe drinking water during its lifetime. The annual cost of the E-GDM system was assessed to be US$5.71 per household, which allows household water treatment in low- and middle-income countries.


2013 ◽  
Vol 14 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Z. P. Bhathena ◽  
S. Shrivastava ◽  
Poonam Londhe ◽  
Joe Brown

Commercial innovation of household-scale water treatment (HWT) devices is rapid in India, where unsafe drinking water contributes to the high burden of disease and death associated with diarrhoeal diseases. Performance testing data for novel devices are not publicly available and there has been no systematic attempt to independently verify manufacturer effectiveness claims. We purchased three gravity-driven HWT devices available on the Indian market to evaluate their performance in reducing bacteria, viruses, and protozoan surrogates in the laboratory according to World Health Organization testing protocols. Results indicated that technologies were moderately effective in reducing Escherichia coli (1.6–2.9 log10) and MS2 (1.4–2.8 log10), and less effective against Bacillus subtilis spores (0.73–2.2 log10) and 3 μm microspheres (0.33–0.56 log10), as means over the testing period (750–4,000 l). Effectiveness declined sharply over the duration of testing for each device, suggesting that the manufacturer-specified effective lifespans were overestimated for all devices. Moderate variability was observed across challenge conditions intended to represent actual use conditions, but performance was not significantly different between challenge waters or ambient testing temperature. Our results suggest that these novel devices do not meet international minimum performance recommendations and that manufacturer effectiveness claims are misleading. Further technological innovation and regulation in this sector may serve to protect public health.


2007 ◽  
Vol 5 (3) ◽  
pp. 385-394 ◽  
Author(s):  
Anyana Banerjee ◽  
Deborah A. McFarland ◽  
Ritu Singh ◽  
Robert Quick

Providing safe water to >1 billion people in need is a major challenge. To address this need, the Safe Water System (SWS) - household water treatment with dilute bleach, safe water storage, and behavior change - has been implemented in >20 countries. To assess the potential sustainability of the SWS, we analyzed costs in Zambia of “Clorin” brand product sold in bottles sufficient for a month of water treatment at a price of $0.09. We analyzed production, marketing, distribution, and overhead costs of Clorin before and after sales reached nationwide scale, and analyzed Clorin sales revenue. The average cost per bottle of Clorin production, marketing and distribution at start-up in 1999 was $1.88 but decreased by 82% to $0.33 in 2003, when >1.7 million bottles were sold. The financial loss per bottle decreased from $1.72 in 1999 to $0.24 in 2003. Net program costs in 2003 were $428,984, or only $0.04 per person-month of protection. A sensitivity analysis showed that if the bottle price increased to $0.18, the project would be self-sustaining at maximum capacity. This analysis demonstrated that efficiencies in the SWS supply chain can be achieved through social marketing. Even with a subsidy, overall program costs per beneficiary are low.


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