Key service areas in urban WASH

As discussed in Study Sessions 1 and 2, urban communities contribute to environmental pollution in many ways. To effectively reduce the impact of such pollution on the environment and its negative effect on the health of the public, it is critically important that service providers are mindful of pollution issues and work efficiently.

There are three key service areas in the WASH sector: water supply, liquid waste and solid waste management services.

Water supply services

Water supply includes the source of water, treatment plant, reservoir and tanks, main trunk lines, distribution lines and individual connection lines for the delivery of potable water. (Potable water is water that is safe to drink.) Treatment systems are not needed where sources are known to be clean and safe, for example water from protected springs and boreholes (Figure 3.2).

Figure 3.2 A protected borehole provides a clean source of water.

Due to the large number of different components required for an efficient system, water supply services require substantial investment. Governments may take loans from international development banks and other foreign agencies to finance large urban infrastructure projects, but in general most of this investment is obtained from the public in the form of tax.

Water supply systems also require adequate finance to operate and function properly. This cost is usually recovered from revenue generated as users pay for the services they get, and depends on the volume of water consumed over a period of time.

A high proportion of the urban population can access an adequate supply of water. However, those living in slum areas often have to buy water from water vendors. They could be paying up to ten times more than those with access to piped water, for water of dubious quality.

Providing an uninterrupted supply of water is a huge challenge for most towns due to limited finance, equipment or manpower. Some sectors of the urban population get more water, while others get only a limited amount. For example, town centre families with higher than average income and water taps on their premises may get a lot more than 20 litres per person per day. Alternatively, poor families who live in peri-urban areas or slums may use less than five litres per person per day.

Sanitation and sewerage services

In addition to urban and rural differences, economic status has a significant impact on sanitation access. In the poorest communities, most of the people are still using open defecation. Although most low-income countries are making an effort to provide services equitably, more work is needed to achieve desired levels of service provision, especially to poorer communities.

Water-flushed toilets need to be connected to a septic tank or to a sewer network. A sewer network includes a system of underground lines (pipes) for collecting and removing liquid wastes from residential, commercial and industrial sources. The sewerage system is used for two major liquid waste categories: blackwater and greywater.

What is meant by the terms greywater and blackwater?

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Greywater is liquid waste from showers, wash basins, dish washing in kitchens and clothes washing. Blackwater is the water flushed from toilets and contains faeces and urine. (You read about this in Study Session 2.)

Most towns and cities in low-income countries do not currently have a sewer network or sewage treatment system. (Sewage means combined greywater, blackwater and other wastewater. It is not the same as sewerage, which means the network of pipes that carry sewage). Most people rely on septic tanks and pit latrines that need regular emptying to safely remove and dispose of faecal sludge.

The local municipality may provide emptying services using vacuum trucks. These trucks provide collection and transport of faecal sludge from households and institutions on a needs basis. Although published statistics are not available, it is often the case that the available trucks cannot meet the demand and users may have to wait to get the service. The waiting time can vary between weeks and months, depending on the available equipment and manpower. Such vacuum truck services may not only be unavailable but also unaffordable.

Solid waste management services

Solid waste management services are another key service area in the WASH sector. Efficient solid waste management is critical for the well-being of urban communities. Without this service, solid waste can accumulate and quickly become a health risk. Figure 1.4 of Study Session 1 shows such a situation.

Solid waste management systems include collection, transport and final disposal systems. With the 3 R approach in mind, waste management may also include separating waste into its different components (glass, metal, plastic, paper, etc.) so that some of the waste can be reused or recycled. Infrastructure and equipment for solid waste management is usually paid for by the government and is therefore a public service. However, there are initiatives in most towns to engage private operators in one or more components of the waste management system.

The solid waste service is usually a low priority service, particularly in small and emerging towns. The general trend is that solid waste management does not become a critical concern until the point where accumulated waste has already become unsightly and caused inconvenience to communities, as illustrated in Figure 3.5.

Figure 3.5 Rubbish tips are unsightly and a potential source of pollution.

Information about access to waste management services in urban areas is not as easily available as information on other services, so less detailed data can be presented here than for water supply and sanitation services. Moreover, since service levels are not clearly defined, it is impossible to accurately and objectively determine the service coverage. However, larger towns that produce significant quantities of waste tend to have better established systems. Some towns have invested in building solid waste disposal sites, but many are still not able to cope with the increasing demand (Figure 3.6).

Figure 3.6 A stream of dirty water cascades down from a landfill site.

Last modified: Sunday, 2 October 2016, 3:04 PM