Evaluation of pit latrine additive "LICE" on the stabilization and sanitization of synthetic faecal sludge

On-site sanitation technologies such as pit latrines are widely used in low-and middle-income countries. In emergency situations, after a disaster leading to an important displacement of persons, pit latrines are often the sanitation facilities built in camps, as being a simple and low-cost technology. These pits are filling up rapidly, and a good management of the accumulating faecal sludge is often missing, which can result in uncontrolled disposal of human excreta and lead to public health and environmental risks. Given the high accumulation rate of faeces, resulting in high pathogens and organic matter content, in these situations, it is important to find a solution to act fast before envisaging more sustainable options. Pit additives have been studied for some time, especially biological ones that could enhance pit latrine content degradation, as well as flies, odour and pathogens reduction, and prolong the life of the pit. The goal of the present thesis was to first synthesize a material that could be used in the laboratory as a simulant of faeces (or faecal sludge) with similar physicochemical characteristics. The material used in this project is closer to human faeces, and some properties should be adapted and further characterized to represent even better pit latrine faecal sludge. The second objective was to evaluate the influence of temperature on the performance of one of this biological additive, “LICE”, that showed quite conclusive results during field study. TS and VS were selected as parameters to assess organic matter degradation and thus stabilization of faeces, whereas E.Coli was the indicator organism to assess bacteria pathogens inactivation, and thus sanitization of faeces. LICE bioadditive doesn’t seem to have a big impact on faeces degradation and stabilization. A very small amount of organic matter was degraded (max. 7-10%) during the 15 days of experiments, and the control containers without additive showed a similar reduction. Concerning E.Coli inactivation, LICE seems to accelerate the inactivation of endogenous bacteria at 35°C. But this statement should be counterbalanced with the fact that this temperature is hardly reachable in real pit conditions, and if it was just about inactivating pathogens in pits, other strong chemical additives have shown quite impressive results.