WASH Technology

Vashi, A. N. and Shah, N. C. (2008). Impacts of a participatory approach to assess sustainable sewage treatment technologies for urban fringe of Surat city in India
Water science & technology-WST ; vol. 57, no. 12 ; p. 1957-1962. doi:10.2166/wst.2008.331

Abstract

This paper describes the assessment of the sustainability of a number of different sewage treatment technologies by means of a multi-criteria, participatory method for a scattered settlement of urban fringe of Surat. The special efforts have been made for the broad participation to achieve stronger democracy, better quality of the end product, and a more effective process. The mere participation of technocrats and bureaucrats certainly lead to the greater efficiency in working methods. However, the ultimate goal of sustainable developments of such technologies could not be reached in absence of democratic participation and social learning. Keeping this important aspect in view for assessment of sustainability, the detailed study was conducted in the presence of policy makers and stakeholders, academicians, technical experts, finance managers and NGO, to find out sustainability criteria and indicators for three different sewage treatment technologies: (A) Conventional Activated Sludge Process (B) Extended Aeration System, and (C) Upflow Anaerobic Sludge Blanket (UASB) Reactor followed by Aerated Lagoon and Polishing Pond. Technologies were compared according to four criteria subdivided into twenty operational indicators. Criteria and indicators were evaluated as in a weighted-scale matrix. In India, sustainability criteria used in this type of comparisons are often restricted to a limited set of environmental impacts and financial costs but in this study additional criteria were evaluated including economic, social, and technical aspects. Based on the values assigned by the panel, the Sustainability Index (SI) was calculated for each technology. According to the SI and a predefined scale, sustainability was medium for options A and B, whereas high for option C. The purpose of this study is to provide a basis for the selection of a particular technology based on a rational and democratic assessment of its contribution to sustainability in the local and global context.

Is it really possible to stop rain, invoke lightning from the heavens or otherwise manipulate the weather? Jane Qiu and Daniel Cressey report on the once-scorned notion of weather modification.

[...]

China has one of the largest programmes for weather modification in the world. It spends between 400 million yuan (US$60 million) and 700 million yuan a year on it, and employs 32,000 people to operate 35 specially equipped planes, 7,000 anti-aircraft cannons and 5,000 rocket launchers. Official figures from the China Meteorological Administration say that the country created 250 billion tonnes of rain between 1999 and 2006, an annual production of more than 30 billion tonnes. This is enough to meet the needs of more than 500 million of its 1.3 billion people, but the country aims to generate 50 billion tonnes a year by 2010.

Many researchers, both in and outside China, doubt that sufficient evidence has been accumulated to support this claimed success. “In fact, China is very much behind in this area,” says Zhang Hong-fa, an atmospheric scientist at the Cold and Arid Regions Environmental and Engineering Research Institute in Lanzhou. “A false sense of achievement would impede genuine progress.”

Read more: Nature, 453, 970-974 (200 - doi:10.1038/453970a - Published online 18 June 2008

A genetic tool used by medical researchers may also be used in a novel approach to remove harmful microbes and viruses from drinking water.

Duke University engineers have demonstrated that short strands of genetic material could successfully target a matching portion of a gene in a common fungus found in water and make it stop working. If this new approach can be perfected, the researchers believe that it could serve as the basis for a point-of-use device to help solve the problem of safe drinking water in Third World countries without water treatment facilities.

The relatively new technology, known as RNA interference (RNAi), makes use of short snippets of genetic material that match — like a lock and key — a corresponding segment of a gene in the target. When these snippets enter a cell and attach to the corresponding segment, they can inhibit or block the action of the target gene. This approach is increasingly being used as a tool in biomedical research, but has not previously been applied to environmental issues.

[...]

In addition to helping solve drinking water issues in underdeveloped countries, this new approach could also address some of the drawbacks (costs, smell/taste, harmful by-products) associated with chlorination and ultraviolet (UV) treatment of drinking water in more developed nations.

Sara Morey, a Ph.D. candidate in the lab of Claudia Gunsch, assistant professor of civil engineering at Duke’s Pratt School of Engineering, who carried out the experiments, presented the results of her experiments [1] on 3 June 2008, during the annual meeting of the American Society of Microbiology in Boston.

Sara Morey, Student, sara.morey [at] duke.edu

Dr. Claudia Gunsch, , Environmental Molecular Biotechnology Laboratory, Duke University Pratt School of Engineering, ckgunsch [at] @duke.edu

[1] S. Morey, S. and Gunsch, C. (2008). Gene silencing of Catechol-2,3-Dioxygenase in Pichia pastoris and Pseudomonas putida. Abstract

See also: Duke University Pratt School of Engineering - Environmental Molecular Biotechnology Laboratory - Antisense RNA and RNA Interference

Source: Richard Merritt, Duke University Pratt School of Engineering, 5 June 2008

Anaerobic digestion represents nowadays one of the most cost-effective alternatives for waste (water) treatment, which has experienced a fast development during the last three decades. This Latin-American Workshop and Symposium will offer a selected program including the latest research findings and technological applications on anaerobic wastewater treatment, solids stabilization and biogas production as a renewal energy source.

This event is addressed to researchers, waste managers, consultants, representatives of both public and private sectors, environmental engineers and other related professionals.

Organised by the International Water Association (IWA).

For more information go to the conference web site

Pioneering work to develop the world’s largest water purification plant for groundwater recharge has earned the Orange County Water District and the Orange County Sanitation District, California, USA, the 2008 Stockholm Industry Water Award. The prestigious distinction will be presented on August 21 during the 2008 World Water Week in Stockholm.

People expect water to be there when they turn on the faucet. But in growing arid regions like Orange County in Southern California, sufficient water is not naturally guaranteed. Fortunately for the 2.3 million residents living there, the Orange County Water District and the Orange County Sanitation District jointly developed the Groundwater Replenishment (GWR) system, a water purification system which will provide enough water to meet the needs of an additional 500 000 people without diminishing groundwater resources for current or future generations.

The GWR System diverts highly treated sewer water that is currently discharged into the ocean and purifies it through a series of advanced techniques: microfiltration, reverse osmosis, ultraviolet disinfection and hydrogen peroxide. The cleaned water is returned to the groundwater basin to increase both water supply and quality. The GWR system has established a blueprint for large-scale wastewater purification that is already being emulated in dry regions and nations, such as Singapore.

Read more: SIWI, 28 May 2008

A pioneering water harvesting system inspired by the Namib Desert Beetle is one the biomimicry innovations that will feature in the first annual edition of Nature’s 100 Best© book. The book is an initiative of ZERI, Biomimicry Guild and the Biomimmicry Institute, in cooperation with IUCN, and UNEP.

The Namib Desert beetle lives in a location that receives a mere half an inch of rain a year yet can harvest water from fogs that blow in gales across the land several mornings each month. A team from the University of Oxford and the UK defense research firm QinetiQ, have designed a surface that mimics the water-attracting bumps and water-shedding valleys on the beetle’s wing scales that allows the insect to collect and funnel droplets thinner than a human hair.

The patchwork surface hinges on small, poppy-seed sized glass spheres in a layer of warm wax that tests show work like the beetle’s wing scales.

Trials have now been carried out to use the beetle film to capture water vapour from cooling towers. Initial tests have shown that the invention can return 10 per cent of lost water and lead to cuts in energy bills for nearby buildings by reducing a city’s heat sink effect.

An estimated 50,000 new water-cooling towers are erected annually and each large system evaporates and loses over 500 million litres.

Other researchers, some with funding from the US Defense Advanced Research Agency, are mimicking the beetle water collection system to develop tents that collect their own water up to surfaces that will ‘mix’ reagents for ‘lab-on-a-chip’ applications.

Source: UNEP, 28 May 2008

A gum membrane made from the seeds of the local konkoli plant - often used as a food thickener - can help remove heavy metals from water. Chemists from Nigeria’s Federal University of Technology say this could be used to clean industrial waste from ore smelting and metal refining.

Osemeahon, S. A., Barminas, J. T, Aliyu, B. A and Nkafamiya, I. I. (2008). Application of grafted membranes for sorption of Cd2+, Fe2+ and Zn2+ ions in aqueous solution. African journal of pure and applied chemistry ; vol. 2, no. 3 ; p. 032-036. Full text

Below is the abstract of the paper by Sally Sutton, which she presented at the 33rd WEDC International Conference in Accra, Ghana, 2008

The MDG indicator for access to safe water equates technology with water quality based largely on designed rather than observed capacity to block routes of faecal contamination. This is a useful driver for donor and government investment in rural water supply, but breeds donor dependency as generally accepted technologies are unaffordable to consumers. Sparse data on water quality suggest a need for greater data collection and more objective assessment of the real improvements being achieved for the donor-dependent investments being made, which are leading to very slow rates of progress. Broadening technology options to include progressively improved household access and water treatment may increase rates of progress, and cost-effectiveness and improve the lot of many more consumers without jeopardising water quality.

Read the full paper here

For more rural water supply technology go to the Rural Water Supply Network web site

The Central Electrochemical Research Institute (CECRI), Karaikudi, India with the sponsorship of Department of Science and Technology (DST), New Delhi, India has developed a Domestic 2A capacity Electro Arsenic Purifier for Drinking Water, which can treat 2L of drinking water per one hour. This unit will reduce the arsenic level from 3ppm to 20ppb (WHO standard). This can also be operated with the use of solar energy.

CECRI also developed a Community model Electro Arsenic Purifier for Drinking water, which can treat 40L of drinking water per one hour.

The cost of the one 2A Arsenic Purifier is Rs 6000 [EUR 95 = US$ 150].

The cost of treatment of water is 3 paise [0.046 Eurocents = 0.075 US$ cents].

Related patent: Electrochemical method for the removal of arsenate from drinking water

Contact: Dr. S. Vasudevan, Scientist, Electroinorganic Chemicals Division, Central Electrochemical Research Institute, Karaikudi – 630 006, India, tel.: +91-4565-227550 /227559, fax: +91-4565-227779,
mobile: 9442552441, Email: svdevan_2000 @ yahoo.com, vasudevan65 @ gmail.com

Source: arsenic-crisis Yahoo! group, 9 Apr 2008

The special issue of Nature on water published to coincide with World Water Day 2008, includes a review of “some of the science and technology being developed to improve the disinfection and decontamination of water, as well as efforts to increase water supplies through the safe re-use of wastewater (e.g. with membrane bioreactors) and efficient desalination of sea and brackish water”. It looks at solutions being developed in the industrialised world, which also have potential for developing countries “where less chemical- and energy-intensive technologies are greatly needed”.

Shannon. M.A. … [et al.] (2008). Science and technology for water purification in the coming decades. Nature ; no. 452 ; p. 301-310. doi: 10.1038/nature06599