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Financing sewage treatment sustainably

There are opportunities for financing sewage treatment systems sustainably.

The most common approach is to charge residents a fee for sewerage. The World Bank (1994) concluded that "there is substantial evidence that urban families are willing to pay substantial amounts for the removal of excreta and wastewater from their neighbourhoods". It must be remembered, however, that the urban poor are often simply unable to pay for sewerage services. [A 1996 report] points out that willingness to pay (usually determined by questionnaire) tends to reflect the importance that people attach to having such services, rather than their realistic assessment of cost or of their ability to pay.

[The report] advises that decisions about cost recovery be made on the basis of ability, rather than willingness, to pay, with a maximum fee of 2% of family income as an accepted standard.

Another option for sustainable financing is to market the water, nutrients, and organic matter contained in sewage, which are valuable resources in most countries.

They can be recovered and used for irrigation, industrial process water, fertilizer, and soil conditioner, while organic matter can be processed into methane to generate electricity. Where markets exist for these products, they may create an economic incentive to invest in treatment. Concerns about public acceptance and health, however, sometimes restrict this option.

Although the GPA/LBA includes only domestic wastewater under the category of "sewage", several regions identify as a priority organic wastes (i.e., BOD, SS, and nutrients) from such activities as animal husbandry and food processing and manufacture. Such wastes, though generally more concentrated than domestic sewage, require similar management approaches to it, and are therefore considered here.

It may be feasible to discharge industrial organic wastes into domestic treatment systems, if these have adequate capacity for the load. It will generally be appropriate in such cases to levy user charges, sufficient to cover the cost of treatment, on the enterprises generating the waste and/ or require on-site pre-treatment of the wastes prior to discharge into the municipal system.

Wherever possible, complete on-site treatment should be encouraged. This forces the internalization of environmental protection costs, and may have technical advantages. The high concentration, for example, may facilitate waste recovery and re-use, while the often less complex mix of substances in the waste stream – and relatively constant (or at least predictable) volume of flow – may lead to savings in unit costs.

The latter advantage, however, may be offset by the declining unit cost of treatment with increasing flow volume.

In the case of feed lots and other intensive animal husbandry operations, it is often necessary to install facilities, such as drains and pits, to intercept wastes in runoff and deliver them to treatment facilities.

Retaining or constructing wetlands may also be effective, particularly where the husbandry enterprises are small and lack the resources to invest in interceptors. [Several authors in a 1998 study] note that discharge standards for animal wastes are generally less stringent than those for human sewage.

International industry has long possessed the capacity to operate and maintain sophisticated systems to treat organic waste.

In developing countries the construction of industrial facilities may create opportunities to harness this capacity for the benefit of local communities, for example by discharging domestic waste into industrial treatment systems

Industrial waste streams that are incompatible with domestic sewage treatment plants, are inadequately treated by them, or exceed their capacity, require specialized treatment tailored to the nature of the waste stream, the receiving environment, and the environmental objectives.

"End-of-pipe" solutions may be effective in reducing the quantity and/or harmfulness of industrial waste discharge, but have limitations. Satisfactory treatment alternatives are not available for all contaminants and sources.

Treatment processes usually involve significant capital, operation, and maintenance costs with little direct economic return to the industry.

For this reason they may not be implemented or, if they are, they may not be properly operated and maintained in the absence of effective regulatory and enforce-ment regimes.

Reduced industrial competitiveness, or the perception of it, may render industrial waste treatment measures socio-economically unacceptable, particularly in developing countries.

Some treatment technologies require technical capacity that is not available in many countries.

"End-of-pipe" solutions are also usually the last stage prior to discharge to the environment, creating a risk of accidental discharge of partially treated or untreated waste in the event of equipment or process failure.

For these reasons, final treatment of industrial wastes is often most effective in preventing environmental degradation when it constitutes just one component of a broader approach to BEP, rather than the primary or only measure employed. In some cases this principle has been formalised. The Baltic JCP, for example, stipulates that the upgrading or completion of industrial wastewater treatment plants should only be supported if there are complementary pre-treatment programmes.