Greywater Management in Low and Middle-Income Countries - SSWM

6.
Finding literature on greywater management systems implemented in low and
is scarce especially when compared to the abundant literature on latrines and toilets
as revealed by the following example: An internet search on Google with the words
countries”. Compared to water supply, excreta and solid waste management
including stormwater drainage, greywater has traditionally been given lowest priority
in environmental sanitation management systems. In urban and peri-urban areas
of low and middle-income countries, greywater discharged untreated onto streets,
into drainage channels, rivers or ponds leads to surface water contamination,
deterioration of living conditions and increased health hazards. However, greywater
is perceived as a valuable resource in rural areas and arid regions where it is often
used untreated in irrigation. Without precautionary measures, this practice may lead
to contamination of food, salinisation and clogging of soils and potentially also to
groundwater pollution.
loads
on living standards, cooking habits, availability of piped water, household demography
etc. Greywater is generally less polluted than other wastewater sources such as toilet
wastewater. However, given the high greywater volumes produced in the household
(typically within the range of 60–120 l/p/d), its contribution to the total pollution load
to 40–50% of the total organic load (expressed as BOD 5), one forth of the total
suspended solids load and up to two thirds of the total phosphorous load. In
contrast to industrial high-income countries where phosphorous-based detergents
have been banned, such products are still widely used in many low and middleincome
countries. In terms of pathogenic contamination, greywater is much safer
than other wastewater sources. Nevertheless, greywater can still contain pathogens
given the likelihood of cross-contamination with excreta. An important characteristic
biological treatment processes.
A system perspective is required to develop sound greywater management
schemes. Source control is crucial to avoid operational problems in subsequent
treatment steps or long-term negative effects on soils. Use of products such as
sodium-based soaps (enhancing the risk of soil salinisation and deteriorating soil
Greywater Management in Low and Middle-Income Countries
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