Greywater Management in Low and Middle-Income Countries - SSWM

Implementation of an environmentally and economically sustainable greywater
management strategy will be easier if control measures at the source (i.e. in
the household) are practised. Source control is by far the most effective way to
reduce pollution loads and avoid operational problems in treatment systems, to
lower management costs and guarantee long-term satisfactory performance of the
treatment systems.
Active participation of all household members is required when applying the
following source control measures:
• minimise water usage
• optimise usage of common cleansing products
• avoid discharge of problematic substances such as oil, fat, bleach, solvents
• substitute hazardous products by environmentally-friendly ones
Minimising water usage can be attained by combining technical and economic
measures. The number of manufacturers of water-saving infrastructure and
equipment is increasing globally (e.g. washing machines or dishwashers with
reduced water consumption or improved tap systems). Indoor water use can be
fee per amount of water consumed (Ridderstolpe, 2004). The potential for reducing
water consumption is highest in regions with high water consumption such as South-
East Asia, Europe or North America. In arid regions where water is scarce and water
consumption lowest, a further reduction of in-house water consumption is generally
not feasible.
Costs and vulnerability of a treatment system are directly linked with the pollution
load in greywater. Design of treatment systems is based on the physical and chemical
and reduced by source control at household level. The level of contamination can
oils, soaps, detergents etc) is reduced. Choice of cleansing products and amounts
and the environment.
Most hard soaps and common washing powders contain sodium salts that
produce a saline greywater and lead to hypertension in plants and salinisation
of soils (see section Reuse in irrigation). When greywater is reused for irrigation,
sodium-containing products should be substituted by potassium-based soaps and
detergents, since potassium has a fertiliser potential and facilitates water uptake by
the plants (Del Porto and Steinfeld, 2000). Most liquid soaps are poor in sodium and
contain potassium. Patterson R.A. (1997) estimated that by simply changing laundry
products, a reduction of up to 38% of the current sodium concentrations in Australian
domestic wastewater can be achieved at no cost to the consumer and without any
negative impacts on household operation.
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