Abstract
In most of the cases caused by natural emergencies like earthquakes, flooding or tsunamis the public supply with electricity, drinking water and waste water breaks down. The public transportation system and the road-and path network will also collapse in a defined area. Especially in less developed countries, in which the public infrastructure is not build up that good anyway, this leads to a high health risk for the affected people because the access to safe drinking water is even more limited. This leads to the point that people drink water from unsafe origins like ponds and rivers. The German federal forces invented the so called common dosage plan to treat water from any contaminated water source (no salt water) to a safe, physical harmless drinking water. The system is based on different water treatment steps, namely flocculation, chlorination and activated carbon filtration. It is a large scale technical process and needs electrical power to run the pumps, stirrers, valves and controls. A group of scientist has adopted this large scale process and developed it to a currentless and simple to operate process, which can be used after natural catastrophes by the affected people. The author of this work was part of a drinking water helping team after the terrible Tsunami 2005. The team operated the drinking water supply for about 1000 refugees in a special tent camp. These experiences in the field work in Sri Lanka 2005 lead to the present work During the field work in Sri Lanka the so called sloping hose process was used. This process is based on the CDP and uses high amounts and concentrations of the treatment chemicals. Especially by the use of the chlorine tablets based on the waterfree disinfectant sodiumdichoroisocyanurate there were negative experiences during the field tests. In summary this was: - Rejection of the treated raw water by the affected people because of the high doses of water treatment the drinking water had a strong chemical smell and also a not common taste. This smell and taste was misinterpreted by the people because they thought the water could be toxic. - Production of high concentration of Trihalomethanes and other water soluble organic halogenated compounds due to the tablet additives of the used chlorine tables - The compounds sodium- and calciumhypochlorite belong to the dangerous goods due to the regulations of the international air transport association and therefore it is not possible to transport these compounds by air for a quick drinking water help action within the first three days after such a catastrophe. Therefore in this work, which was restricted to the investigation of stipulated German products due to the German emergency water legislation, namely the three compounds sodiumhypochlorite (NaOCl), calciumhypochlorite (Ca(OCl)2) and sodiumdichloroicocyanurate (NaCl2(CNO)3) as waterfree compound or as dihydrate were compared as the only in Germany permitted disinfectants by measuring their efficiency during the chlorination of so called “worst case water”. This water quality was defined by the highest German Technical Drinking Water Authority (DVGW) as the effluent of a municipal waste water plant with at least 300.000 inhabitants and is the worst water quality, which could be used for the drinking water supply as raw water in emergencies. All experiments were carried out as simple batch experiments. Additional a special chlorine-producing anodic oxidation device (diamond electrode) was tested.