Small-scale methods for treating sewage and providing safe water in Nepal
In Nepal, less than a third of people have access to proper sanitation and water-borne diseases represent the biggest threat to children.
According to the World Health Organization (WHO), in 2008, nearly two-fifths of deaths among children under five were caused by diarrhoeal illness. And more than 1 in 10 outpatient visits in Nepal are linked to water or food-borne diseases.
With a limited network of sewers, only 5% of the country’s wastewater is treated conventionally. Waste is commonly diverted into drains or pipes which empty into rivers. The main cost of traditional water-treatment systems lies in building the infrastructure to carry wastewater from its source to treatment plants. In addition, the skilled technicians required to run conventional centres are in short supply.
Now IRIN reports on calls to set up more small decentralized treatment facilities. These treatment plants often rely on natural techniques. For example, a plant set up in Sunga, 8 kilometres from Kathmandu, uses beds of coarse sand and gravel, along with reed plants. These beds filter the wastewater before it is released into a local river. Around 30 small community-based plants have been constructed over the last 15 years, using a combination of both public and private investment. Experts believe such de-centralised systems could be the best way to improve the management of wastewater in Nepal.
Another pressing water issue for Nepal was highlighted in a January IRIN article. According to the WHO, around 90% of Nepalese people have access to improved drinking water sources. However, over a decade ago it was discovered that many groundwater sources contained unsafe levels of arsenic. An estimated 2.7 million Nepalese – around 10% of the population – are using water which has concentrations of arsenic above WHO recommended levels. In one district alone, nearly 4,000 wells were affected.
Though water filters were installed in many thousands of tube wells, often these were not being properly maintained or replaced when broken. Whereas diarrhoea can kill a child within days, arsenic can take 10 years to build up to life-threatening levels. Cancers caused by arsenic can lay dormant for many years. Communities have therefore been slow to react, though young adults in some regions are now dying prematurely of arsenic-related illnesses. Until the problem can be solved permanently, with deep-bore wells and storage tanks for example, charities are calling for greater use of small-scale solutions, such as household filters. Six low-cost filter technologies have been certified for sale in Bangladesh, one of the nations worst-affected by arsenic-tainted drinking water. Some experts are now calling for these kinds of filter to be offered to Nepalese families at a subsidized cost. As with the water-treatment plants, the view is that the best solution for now is the small one.