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Some two million tons of waste is being discharged daily into rivers and seas spreading disease to humans and damaging key ecosystems such as coral reefs and fisheries, according to a new United Nations report published yesterday on World Water Day.
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, the UN Environmental Programme (UNEP) states in the report, called "Sick Water."
Unless decisive action is taken, it is a challenge that will continue to intensify as the world undergoes rapid urbanization, industrialization and increasing demand for meat and other foods.
Urban populations are projected to nearly double in 40 years, from current 3.4 billion to over six billion people–but already most cities lack adequate wastewater management due to aging, absent or inadequate sewage infrastructure.
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% 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".
Some Solutions
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 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 favour conservation and restoration over draining wetlands for farmland.
Other solutions can be small-scale: The report cites the coral coast of Fiji where it was estimated that up to 40% 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.
Achim Steiner, UN Under-Secretary General and Executive Director of the UN Environment Programme (UNEP), said: "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."
"The facts and figures are stark – pollution from wastewater is quite literally killing people, indeed at least 1.8 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. 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," Mr Steiner said.
Mrs Anna Tibajuka, Executive Director of UN-Habitat, said: "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."
"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 Mrs Tibajuka.
The full report is available a the link below and includes six recommendations for addressing water security worldwide.
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