Hydraulic ram pumps and Sling Pumps

Technical Information W9ealternately. Only one of the pits at a timewill be in use while the contents of theother is left for degradation – given aproper dimensioning, for a period ofseveral years. The well degraded materialwill be a lot easier to remove than mixedrotted and fresh material.3.4 Compost toiletShould the recycling of nutrients containedin the human excreta into agri- orhorticulture be intended, a compost toiletmay be an appropriate solution for basicsanitation if there are no culturallyconditioned reservations againstreutilisation of excrements.The composting of human excretarequires additional organic matter for afavourable nutrient ratio (C:N) in thesubstrate, which can be provided byregular addition of ash, sawdust, peat,straw, organic household waste or similarsubstances every time the toilet is used.To achieve an acceptable state of maturityof the compost, a retention time of two tofive years has to be assumed.An important aspect to be taken intoconsideration is the pathogen content ofthe compost if directly applied to cropmeant for human consumption. In order tominimise the health risk, it should not beapplied later than three weeks beforeharvesting [1] and in general with focus onsoil improvement rather than immediatefertilising.The available areas should be sufficientfor the application of the producedcompost.Compost toilets can be operated in batchor continuous mode.3.4.1 Batch compostingThe design of batch compost toilets iscomparable to pit latrines, usuallyconsisting of a two-pit or a double-vaultsystem (see Fig. 5) and a superstructure.The vaults are built next to each other andusually used alternately year by year,allowing longer composting periods. Theyare accessible from outside for substrate5removal which has to be done manually. Apit will be topped up with earth when it isfilled up to 2/3 – 3/4 with excreta andadditional organic matter. As neitheraeration nor substrate mixing is realised inthe pits, the composting process will partlybe anaerobic and will only reachtemperatures of approximately 35 °C.Fig. 5: Double-vault composting toilet. [1]Prior to the first use, the base of acomposting pit has to be covered with peator humus and grass in order to provideproper conditions for a compostingprocess. The volume approximatelyrequired per person is 0.4 m³, assuming0.3 m³ of waste is produced per personand year and considering that the pit hasto be emptied if it is filled up to 3/4.3.4.2 Continuous compostingFor continuous operation, only one pit isrequired which is accessible for regularremoval of compost. The differentmodifications are principally all based on aSwedish design, the so-called “multrumtoilet” (see Fig. 6).gate Information Service / gtz, PO Box 5180, 65726 Eschborn, GermanyPhone: +49 (0)6196 / 79-3093, Fax: +49 (0)6196 / 79-7352, Email: gate-id@gtz.de, Internet: http://www.gtz.de/gate/gateid.afp