By Ben Ochieng

Transforming wastewater from a major health and environmental hazard into a clean, safe and economically-attractive resource is emerging as a key challenge in the 21st century.

It is a challenge that will continue to intensify as the world undergoes rapid urbanization, industrialization and increasing demand for meat and other foods unless decisive action is taken says a new United Nations report released in Nairobi on Monday.

Urban populations are projected to nearly double in 40 years, from current 3.4 billion to over six billion people �C but already most cities lack adequate wastewater management due to aging, absent or inadequate sewage infrastructure.

The new report, called Sick Water?, says some two million tons of waste, estimated to equal two or more billion tons of wastewater (see notes to editors) is being discharged daily into rivers and seas spreading disease to humans and damaging key ecosystems such as coral reefs and fisheries. "If the world is to thrive, let alone to survive on a planet of six billion people heading to over nine billion by 2050, we need to get collectively smarter and more intelligent about how we manage waste including wastewaters," said Executive Director of the UN Environment Program (UNEP) Achim Steiner. "The facts and figures are stark -- pollution from wastewater is quite literally killing people, indeed two million children die annually as a result of contaminated water. The impacts on the wider environment and in particular the marine environment are also sobering," he added. "But the report also points to the abundant Green Economy opportunities for turning a mounting challenge into an opportunity with multiple benefits," Steiner said. "These include the savings from reduced fertilizer costs for farmers and, incentives for conserving ecological infrastructure such as wetlands alongside new business and employment opportunities in engineering and natural resource management."

Wastewater is a cocktail of fertilizer run-off and sewage disposal alongside animal, industrial, agricultural and other wastes.

The report says that the sheer scale of dirty water means more people now die from contaminated and polluted water than from all forms of violence including wars.

Dirty water is also a key factor in the rise of de-oxygenated dead zones that have been emerging in seas and oceans across the globe.

Yet many of the substances that make wastewater a pollutant-- for example nitrogen and phosphorus-- can also be useful as fertilizers for agriculture. Wastewater can also generate gases to fuel small power stations or be used for cooking.

The report notes that already some 10 per cent of the world's population is being supplied with food grown using wastewater for irrigation and fertilizer and with better management and training of farmers this could be increased substantially.

The report, launched to coincide with World Water Day, goes so far as to say that the concentration of nutrients in wastewater "could supply much of the nitrogen and much of the phosphorous and potassium normally required for crop production.

Other valuable micro-nutrients and organic matter contained in the effluent would also provide benefits".

The report underlines that reducing the volume and concentrations of wastewater will require multiple actions ranging from reducing run-off from livestock and croplands to better treatment of human wastes.

Some solutions may involve water recycling systems and multi- million or multi-billion dollar water sewage treatment works: the report cites the success of those installed in the Bali coastal resort of Nusa Dua in Indonesia.

Others may involve investing and re-investing in nature's natural purification systems which include wetlands, mangroves and salt marshes.

Studies in the Mississippi valley of the United States indicate that the value of a restored wetland may be as high as over 1,000 US dollars a hectare if its full range of services, from water filtration to recreational use, is factored in.

Establishing markets and economic instruments for such services could offer the kind of financial incentives that favor conservation and restoration over draining wetlands for farmland.

The report cites the coral coast of Fiji where it was estimated that up to 40 per cent of harmful nutrients being discharged into the marine environment were from pigs, which produce three times more concentrated nitrogen waste than humans.

Sawdust beds which soak up the liquid run-off from pig pens have now been introduced, and soiled sawdust is shipped to nearby farms as fertilizer. Emissions to coastal waters have been cut and the farmers are pleased too.

This is because the more comfortable sawdust beds seem to make the pigs happier and thus bigger, so farmers have more meat to sell. "Urban and industrial wastewater composed of sediment, nutrients, organic matter, trace metals and pesticides, among others, adversely affects the entire food chain and thus human health," said Anna Tibajuka, Executive Director of UN-Habitat. "Many water and sanitation utilities, especially in developing countries, are forced to spend more financial resources in water treatment due to increased pollution. Excess nutrients and wastewater can also lead to uncontrolled growth of algae and aquatic plants such as water hyacinth which cause practical problems for marine transportation, fishing and at intakes for water, hydro power and irrigation schemes," she added. "It is my hope that activities taking place globally today will raise public awareness of the water quality challenges facing humanity, and the need to commit to concrete remedial actions at all levels," said Tibajuka.

Christian Nellemann, a lead author on the report, added: "Some estimates suggest that around 2 million tons of waste are spilled into sewage systems every day: this may be producing well over two billion tons of polluted water every single day, 365 days a year, right into our freshwaters and oceans".

The Rapid Response Assessment, entitled "Sick water? The central role of wastewater management in sustainable development", has been compiled by a special taskforce consisting of the UNEP, the UN-HABITAT, and the UN Secretary General's Advisory Board on Water and Sanitation (UNSGAB).

The report shows that the impact of poor wastewater management and degrading sewage systems is not only costing billions of dollars and degrading ecosystems, it is also challenging the achievement of the Millennium Development Goals, sustainable development, jobs, labor productivity and the health of hundreds of millions of people worldwide.

Conversely, a recent report by the UNEP Green Economy Initiative underlined the economic benefits of investing in this resource. It argues that every dollar invested in safe water and sanitation has a pay back of 3 dollars to 34 dollars depending on the region and the technology deployed.