The Lancet Commission on pollution and health

Nanotechnology, the engineering and art of manipulating matter at the nanoscale (1-100 nm), offers the potential of novel nanomaterials for treatment of surface water, groundwater, and wastewater contaminated by toxic metal ions, organic and inorganic solutes, and microorganisms. Due to their unique activity toward recalcitrant contaminants and application flexibility, many nanomaterials are under active research and development. Accordingly, literature about current research on different nanomaterials (nanostructured catalytic membranes, nanosorbents, nanocatalysts, and bioactive nanoparticles) and their application in water treatment, purification and disinfection is reviewed in this article. Moreover, knowledge regarding toxicological effects of engineered nanomaterials on humans and the environment is presented.

Nanotechnology and Water Treatment: Applications and Emerging Opportunities

The rapidly increasing population, depleting water resources, and climate change resulting in prolonged droughts and floods have rendered drinking water a competitive resource in many parts of the world. The development of cost-effective and stable materials and methods for providing the fresh water in adequate amounts is the need of the water industry. Traditional water/wastewater treatment technologies remain ineffective for providing adequate safe water due to increasing demand of water coupled with stringent health guidelines and emerging contaminants. Nanotechnology-based multifunctional and highly efficient processes are providing affordable solutions to water/wastewater treatments that do not rely on large infrastructures or centralized systems. The aim of the present study is to review the possible applications of the nanoparticles/fibers for the removal of pollutants from water/wastewater. The paper will briefly overview the availability and practice of different nanomaterials (particles or fibers) for removal of viruses, inorganic solutes, heavy metals, metal ions, complex organic compounds, natural organic matter, nitrate, and other pollutants present in surface water, ground water, and/or industrial water. Finally, recommendations are made based on the current practices of nanotechnology applications in water industry for a stand-alone water purification unit for removing all types of contaminants from wastewater.

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A Review of Removal of Pollutants from Water/Wastewater Using Different Types of Nanomaterials

Monitoring of progress towards the Millennium Development Goal (MDG) drinking water target relies on classification of water sources as “improved” or “unimproved” as an indicator for water safety. We adjust the current Joint Monitoring Programme (JMP) estimate by accounting for microbial water quality and sanitary risk using the only-nationally representative water quality data currently available, that from the WHO and UNICEF “Rapid Assessment of Drinking Water Quality”. A principal components analysis (PCA) of national environmental and development indicators was used to create models that predicted, for most countries, the proportions of piped and of other-improved water supplies that are faecally contaminated; and of these sources, the proportions that lack basic sanitary protection against contamination. We estimate that 1.8 billion people (28% of the global population) used unsafe water in 2010. The 2010 JMP estimate is that 783 million people (11%) use unimproved sources. Our estimates revise the 1990 baseline from 23% to 37%, and the target from 12% to 18%, resulting in a shortfall of 10% of the global population towards the MDG target in 2010. In contrast, using the indicator “use of an improved source” suggests that the MDG target for drinking-water has already been achieved. We estimate that an additional 1.2 billion (18%) use water from sources or systems with significant sanitary risks. While our estimate is imprecise, the magnitude of the estimate and the health and development implications suggest that greater attention is needed to better understand and manage drinking water safety.

https://www.mdpi.com/1660-4601/9/3/880/pdf

Global Access to Safe Water: Accounting for Water Quality and the Resulting Impact on MDG Progress

The quality of drinking water in the United States is among the best in the world; however, waterborne disease outbreaks continue to occur, and many more cases of endemic illness are estimated. Documented waterborne disease outbreaks are primarily the result of technological failures or failure to treat the water (Craun et al. 2006). Current federal regulations require that all surface waters used for a drinking water supply be treated to reduce the level of pathogens so as to reduce the risk of infection to 1:10,000 per year (Regli et al. 1991). To achieve this goal, water treatment must, at a minimum, reduce infectious viruses by 99.99% and protozoan parasites by 99.9% (Regli et al. 2003). If Cryptosporidium concentrations exceed a certain level in the source water, additional reductions are required. This degree of treatment is usually achieved by a combination of physical processes (coagulation, sedimentation, and filtration) and disinfection (chlorination, ozonation). Filtration is essential for the removal of protozoan parasites due to their resistance to chlorination and ozonation at doses normally used in drinking water treatment (Barbeau et al. 2000; Korich et al. 1990; Rennecker et al. 1999). A variance from filtration is allowed in some cases if the watershed is protected and carefully monitored for protozoan pathogens.

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Risk of waterborne illness via drinking water in the United States.

Rapidly growing populations and migration to urban areas in developing countries has resulted in a vital need for the establishment of centralized water systems to disseminate potable water to residents. Protected source water and modern, well-maintained drinking water treatment plants can provide water adequate for human consumption. However, ageing, stressed or poorly maintained distribution systems can cause the quality of piped drinking water to deteriorate below acceptable levels and pose serious health risks. This review will outline distribution system deficiencies in developing countries caused by: the failure to disinfect water or maintain a proper disinfection residual; low pipeline water pressure; intermittent service; excessive network leakages; corrosion of parts; inadequate sewage disposal; and inequitable pricing and usage of water. Through improved research, monitoring and surveillance, increased understanding of distribution system deficiencies may focus limited resources on key areas in an effort to improve public health and decrease global disease burden.

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Ellen J. Lee

Papers

Deficiencies in drinking water distribution systems in developing countries.