Aqua Privy Sewerage Systems A Survey Of Some Schemes In Zambia

Abstract

Sanitation in c<;velooing countr~_es The greatest challenge for the people concerned with environmental health in developing countries is that of water supply and excreta disposal systems in high density. low-income urban co~munities. Recent statistics show that only a minor part of the population lives in houses connected to waterborne aewez aqe , Sanitary disposal methods in zambia (figures in percentages) URBAN CENTRES LUSAI<A 1969 (1) 1974(2) 1976 (3) 1969(1) 1974 (2) 1976 (3) Flush toilets 56,7 46.2 43,9 42.3 39,4 37.3 Aqua privy 7,0 5,4 5.5 2.9 1.4 1.2 Pit latrine 26,7 37,7 40.1 46.1 52.1 53,7 Bucket 2,1 1.5 1,3 6,5 3.1 2,7 None .2.t2 9,2 -.2.t..£ 2,2 -..!t~ 4,7 lOO"~ lOO"~ 100% 100% 100% 100% These figures demonstrate the fact that whatever the official poli~~ is, the proportion of dwellings with full services is rapidly declining. Therefore, it seems that even When the official policy is to provide full services for every individual dwelling; in practice only a.small proportion of new dwellings will enjoy these facilities. The occupants of low income housing estates have often a rudimentary or totally absent health education. and sometimes these people have little comprehension of the reason for sani tary pr ecaut.Lons , Therefore, thev do not have health protective habits for urban living. Consequently, the sanitary systems must provide security against the possibility of ill-health as a result from mismanagement or misuse of the system. An effic:er: sanitary system does not necessarily mean a sophisticatt~,1.sy st.em, The provision of a sanitary system beyond the technological competence of the community could be a waste of money and effort. Mechanical flushing systems (which require attention to the waterlevel mechanism), U traps in toilets (which becon.e blocked where toile~ paper is not common), and U traps in washing sinks (where sand and porridge cause bloc~·:ages), can ruin tha conventional waterborne system. 1. CSO Census of popu1.ation and housing 1969 2. J.T. Robertson "The urban situation Shelter" 1974. 3. Estimate made by Ministry of local Government and Housing. Figures are not strictly comparable due to boundary changes in Lusaka 3nd in urban are.as. -2- We also must not forget the environmental hazards involved and the increased water consumption for a toilet system. In a low income housing estate the user converts daily around 40 litres of clean drinking water. about 5~~ of his total consumption. into pathogenic matter which even in an expensive treatment cycle cannot be completely sterilized. This deterioration of the existing situation can be prevented or minimized only by the introduction of an "appropriate iDfc4·r.rnediate"solution, which can be afforded both by the nation and by householders and which can be provided at a rate consistent with that of urban growth. The aqua-privy sewerage can be one of the solutions in this field. The following literature mentions the Zambian solution: Disposal of community waste water WHO Technical Report ~o.541 Rural sanitation in the tropics The Ross Institute Waste Stabilization Ponds WHO publication Gloyna Sewage Treatment in hot climates D. Mara Stop the Faeceal Peril lDRe report Water Waste and Health in hot climates by Feachem. M. l-1c Garry and D. Mara A system of sanitation for low- . cost high den3ity housing by L.J. Vincent. W.E. Algie and G. Marias