Public health risks assessment of decentralized wastewater treatment systems in Port Harcourt City, Nigeria | |
| Author | Cookey, Peter Emmanuel |
| Call Number | AIT Thesis no.ET-SUD-13-01 |
| Subject(s) | Water quality--Nigeria Public health--Nigeria Sewage--Purification--Nigeria Drinking water--Risk assessment--Nigeria |
| Note | A thesis submitted in partial fulfillment of the requirement for the Double Master Degree in Environmental Techno logy for Sustainable Development , Master of Environmental Engineering Management (AIT), Master of Environmental Science and Technology (UNESCO - IHE) |
| Publisher | Asian Institute of Technology |
| Abstract | Public Health Risk s Assessment of Decentralized Wastewater Treatment System in the city of Port Harcourt and its environs (which includes both Port Harcourt City Council and Obio Akpor LGA) were carried out. Performance audit of more than 140 On - site Wastewater Treatment Systems, investigation s int o the governance and regulatory of sewage management system and physico - chemical and microbiological water quality analysis of 20 selected private water boreholes in premises with septic tanks toilets system were carried out. Data obtained from this investigation were used for public health risk s assessment where quantification of exposure (chemical and microbial constituent of concerns) and quantification of probability to risk of infection (fecal Coliform Organisms) and Hazard Quotient i.e. Systemic Toxicity (Nitrates) were estimated. The correlation between the risk of infections to setback distance of water boreholes to septic tanks was determined as well as development of public health risk map. The microbial water quality results showed that 45 percent of the sampled private water boreholes in the study area were heavily contaminated with fecal coliform organisms. The pH of 19 out of 20 samples was below the recommended standards of WHO and the Nigerian Standards Organization. All other parameters we re within the drinking water recommended standards. The study also, showed a very clear relationship between microbial contaminations of water boreholes and septic tanks setback distance. The fecal coliform organism’s contaminations of sampled water were seen in samples with setback - safe - distance below 8 meters. The estimation of the Fecal Coliform Organisms intake from ingestion of water by drinking and beverages making showed a very high intake in 9 sites for children and adults while 11 sites had a reduced ingestion rate of microbial organisms. The results showed that a child tends to take in more pathogenic organisms than the adult. The same was the case for accidental ingestion of water while taking baths. The nitrates intakes in all cases were of very low concentrations however, even with low concentration, a child takes in more doses than an adult. The exposure of a child and adult to microbes (fecal coliform organisms) that may likely result to risk of infection which exceeded the guidelines standard of 1x10 - 4 (Kolluru et al, 1996) by ingestion of water through drinking and beverages making and accidental ingestion of water while taking baths were in 45 percent of the sampling sites and 55 percent of the sampling sites had very low risk of infection. Also, a child tends to be more vulnerable to the risk of infection than an adult. In all the sites, nitrates hazard quotient (systemic toxicity) was below 1.6mg/kg - day Reference Dose (RfD) value (USEPA, 2002, RAIS, 2003). There were significance correlation between the risk of infections and setback distance of water boreholes to septic tanks and the public health risks map showed widespread risk to infection in the city. The other findings of the study revealed that most of the septic tanks in the study area were suffering from various degrees of failures which include: cracks, structural deteriorations, leakages, inappropriate locations, inadequate separation distance to groundwater sources, improper designs or installation and poor maintenance. Conclusively, there is a total absence of adequate regulatory, legislative standards for sustainable decentralized wastewater treatment systems in the study area. |
| Year | 2013 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Thammarat Koottatep |
| Examination Committee(s) | Ajit P. Annachhatre;Oleg Shipin |
| Scholarship Donor(s) | Peter van der Steen - UNESCO - IHE;Rivers State Sustainable Development Agency (RSSDA);Rivers State Government, Nigeria. |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology - UNESCO-IHE, 2013 |