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an accumulation rate of sludge of little more than 10 litres per person per year, largely confirming the earlier observations. |
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When the rehabilitation programme was concluded in 1986, no agency assumed official responsibility for the ASAS pilot projects. During a visit to Pasacaballos in 1988 it was found that the sewers had been removed and the connection boxes had been destroyed. Subsequent housing development in the area resulted in many homes being demolished and many of the householders changing houses, effectively terminating the project. In January 1995, two houses still had their septic tank, but it discharged directly into the street gutter. It was, however, encouraging to note that these two septic tanks have not required desludging and were found to be functioning properly. This was also the case with the other septic tanks used in the project until they were abandoned. |
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It has become clear that the main functions of the septic tanks are to retain solids and mitigate the sudden impact of toilet discharges; while the stabilization of organic matter is important and is usually attained to an acceptable degree, it is not the main criterion on which to base the size of the tank. For this reason, in the technical specifications relating to the ASAS system, septic tanks are more accurately defined as interceptor tanks. |
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Since the pilot projects, the ASAS system has generated considerable interest both in Colombia and abroad. The Colombian Government commissioned a further two pilot projects to investigate the social acceptability of the ASAS technology as an option for small towns and villages and low-income urban areas. Two ASAS systems have been built in Granada and San Zenon (2500 and 1500 people, respectively) located in the northern region, about 200 km south of Cartagena. The systems began operating in May 1995, and the experience during construction and initial operation of both systems has been excellent in terms of social acceptance, community participation and confirmation of the hydraulic design of the system. In addition, simple, low-cost equipment for desludging the septic tanks has been developed. Manuals for operating and maintaining the systems have been prepared, including instructions for monitoring and cleaning the |
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