Transcript Document
Environmental sanitation planning and infrastructures in developing countries Faecal Sludge Collection and transport technologies Doulaye Koné SANDEC / EAWAG – Switzerland www.sandec.ch [email protected] Tel.+41 44 823 55 53 1 On-site sanitation = the hidden reality 1. 70-100 % of cities and towns in developing countries served by on-site sanitation (latrines and septic tanks) 2. All installations produce FS to be collected ( trucks replacing sewer lines ?) 3. Lack of regulations, illegal dumping and use of FS untreated 2 Challenges: how to shift our mind set? Engineers’ thrusts and beliefs How to empty this pit ? What happens next ? The challenge Problems Pit emptying and FS haulage Traffic congestion No access to pits 4 The challenge • Distance? • Reuse potential? • Humidity (hygienic quality)? • Additional treatment (storage)? • Greywater collection transportation and treatment? • Quantity (size of neighbourhood)? • Business opportunity? Latrines emptying technology How does latrines technologies influence emptying technologies and performances ? DRY PIT LATRINE POUR FLUSH LATRINE SUCKING FROM TOP LEAVES DENSE SLUDGE WATER ADDED FROM TOP DOES NOT MIX HAND STIRRING IS NOT EFFECTIVE SUCKING FROM BOTTOM REMOVES SLUDGE FIRST INJECTED WATER MIXES WITH SLUDGE WATERTIGHT PIT BOTTOM MAKES SUCKING EASIER Urine diverted latrine Faecal sludge viscosity % H2O Sludge composition - Flow Behaviour (Bösch & Schertenleib, 1985) 100 1 80 2 3 60 4 40 20 0 0 2 4 6 8 10 12 % Volatile (TVS) 1.low- viscosity zone 2.low- : low+ viscosity zone 3.med : med+ viscosity zone 4.high- : high+ viscosity zone Manual emptying where trucks cannot access/pump or households cannot pay the service Manual emptying (70%) Dupimg in the street, Reuse in agriculture In the street Photo: P. Blunier, 2004 Manual emptying where trucks cannot access/pump or households cannot pay the service Transportation of manually-emptied solids and liquids Animal-cart transportation Locally manufactured emptying technology Collection of dried sludge Vacutug Specifications • WEIGHT: 950 KG. • SIZE : L 3900mm X W 1350-mm X H 2000 mm • SPEED: 5 Km/hr • ENGINE: Four stroke 8 HP HONDA models GX240 petrol engine with Electronic ignition. • VACUUM PUMP • TANK : 500 liters capacity • CAPITAL COST of MARK II: USD$ 5,100 (excluding freight) UN-Habitat Vacutug • A Vietnamese model e.g. Haiphong: Tanks in narrow lanes accessible by small vehicles 24 TRACTOR TRAILED VACUUM TANKER MICRAVAC Imported cesspits trucks • • • • Expensive maintenance Spare parts often lacking Out of age Not appropriate Locally manufactured cesspits trucks • Low-cost operation and maintenance • Maintenance skills and spare parts available Locally manufactured cesspits trucks