Surface and underground water in Bwaise III is heavily contaminated. Dangerous nutrients from sanitation pollutants end up in L. Victoria posing a public health and environmental threat. A new study by Makerere University has revealed. Bwaise III, a Kampala suburb is one of the typical slums with poor sanitation infrastructure, situated in a low lying area drained by Nsooba and Nakamiro open storm water channels.
The four year research project was carried out through PhD and MSc research studies, under the SCUSA research project aimed at addressing challenges of sanitation provision in slums. The research started in Jan 2009 and will run till December 2012.
SCUSA stands for integrated approaches and strategies to address the sanitation crisis in unsewered slum areas in African mega-cities. The project is a cooperation between UNESCO-IHE Institute for Water Education, Makerere University and Kampala Capital City Authority (KCCA). The research focused on developing criteria on how researchers and implementers can select appropriate technologies suitable for different practical situations based on what has been implemented elsewhere.
The study indicates that existing sanitation systems in Bwaise lll are unsustainable while excreta disposal facilities and solid waste collection points are largely unimproved leading to ground water pollution and unhygienic conditions. Waterborne viruses (Rota viruses, Hepatitis A viruses, Human Adenoviruses F and G) were detected in surface water, grey water and from ground water from beneath pit latrines. In addition Human Adenoviruses F and G were also detected in spring water used for domestic purposes. The widespread of pathogenic viruses pose a potential public health risk and underlines the need for sanitation improvement in slums.
Results showed that catchments where Bwaise lll slum is located were contaminated with nutrients from sanitation activities. Storm water channels contained high levels of phosphate and ammonium and were depleted of dissolved oxygen (with more than 1mg/L). Spring water was contaminated with nitrates (30-90mgL as NO3). This widespread presence of nutrients requires implementation of a range of measures to improve the existing sanitation in order to improve the quality of water and safe guard down stream lakes from eutrophication.
“We have indeed found out that grey water is heavily polluted from the concentration of indicator organisms, pathogenic viruses and its bacteriological qualities compared to that of sewage and, its strength is compared to that of industrial waste water,” PhD Researcher Eng. Alex Katukiza told participants. He was speaking during the stake holders meeting on Sanitation in slums held on 20th March 2012 at Hotel Africana which attracted participants from UNESCO, Kampala Capital City Authority (KCCA), Ministry of Water and Environment, National Water and Sewage Corporation (NWSC) and Makerere University.
Katukiza reported that although pit latrines polluted ground water significantly, they can be a good option for the removal of nutrients. Phosphorus removal was almost complete due to retention in the pit and surrounding soil. The removal of nitrogen species was about 80% leaving the rest as nitrates in the soil (NO3) in ground water system by denitrification. Hence the potential of polluted ground water to cause eutrophication is rather limited.
Another component of the research looked the Hydrological aspects to understand the mechanisms which control the transport of pollutants generated from onsite sanitation. The focus was on nutrient pollutants (nitrogen and phosphorus) which were discharged in drainage surface water and underground water. Researchers revealed that excess nutrients cause eutrophication and excessive algae growth problems in L. Victoria and other reservoirs.
The concentration of Nitrogen (30-70 mg/l TKN) and Phosphorus (2-10mg/l) in grey water implies that it contributes to the nutrient load in surface water. In addition, the concentration of E.coli (max.5x10CFU/100ml) is a public health concern. Hence there is need to prioritize grey water management (treatment and safe disposal) to minimize water borne disease out breaks and environmental pollution..
“We looked at the water borne viruses in the slum environment, and the uncontrolled release of waste water and solid waste. We discovered that high concentration for pathogens in waste, surfaced and ground water has increased the prevalence of infectious disease of the slum environment. We also found that Nitrogen and Phosphorus nutrients are a result of poor sanitation in the areas and we want to know how infected water goes into Lake Victoria”. Another researcher, Philip Nyenje said.
Researchers emphasize the need to reduce the flow of Nitrogen and Phosphorus nutrients from toilets into the drainage and L. Victoria by using sanitation options and technologies. Other recommendations include increased monitoring, research and innovations on preservation of the environment and enhancing peoples’ awareness of the magnitudes of the risks associated with sanitation systems and evidence based interventions.
“The major problem is for those people and organizations that have been intervening whenever there is an outbreak, There is very limited environmental monitoring of what is happening in research so that one can relate pollution to infections in the population within the slum environment. We have to really look at the causes of these out breaks”. Eng Katukiza recommended.
The project was funded by the Netherlands organization for development cooperation (DGIS) at an estimated cost of about 800,000 Euros. It is an integrated project consisting of the technical host and technical part of the Sanitation, Hydrology and social, economic components aimed at solving the sanitation problem in peri urban areas.