Surveillance of Invasive Bacterial Pathogens and Human Enteric Viruses in Wastewater Final Effluents and Receiving Water Bodies – a Case Study from Durban, South Africa

Abstract

The physico-chemical characteristics and microbial composition of the final effluents of two municipal wastewater treatment plants in South Africa were assessed between July and September 2009. The impact of the treated final effluents on the receiving water bodies was also evaluated. The temperature across all sampling points ranged between 14 and 228C, while pH varied from 6.9 to 7.6. High levels of turbidity, chemical oxygen demand (COD), ammonia, nitrate, nitrite and orthophosphate (PO 4 ) were observed in many cases. Turbidity of the samples was in the range of 2.2-288.6 NTU. The concentrations (mg/L) of other physico-chemical parameters are as follows: COD (9.33-289); ammonia (0.000340-45.4); nitrate (0.062-539); nitrite (0.021-22.6); PO 4 (5.3-33.2). The microbial quality of the effluents discharged from the plants did not comply with the limits set by the South African guidelines with respect to pathogens such as Salmonella, Shigella, Escherichia coli, total coliform, faecal coliform, enterococci, faecal streptococci, and viral particles for effluents intended for discharge into receiving watersheds. This study revealed an undesirable impact on the physico-chemical and microbial qualities of the receiving water bodies as a result of the discharge of inadequately treated effluents from the wastewater treatment facilities. This poses a health risk to several rural communities which rely on the receiving water bodies primarily as their sources of domestic water and recreational purposes. There is therefore a need for the intervention of appropriate regulatory agencies in South Africa to ensure compliance of treatment facilities with wastewater effluent quality standards.

Prevalence of Antimicrobial Resistant and Virulent Salmonella spp. in Treated Effluent and Receiving Aquatic Milieu of Wastewater Treatment Plants in Durban, South Africa

“…Two wastewater treatment plants, namely the Northern Wastewater Treatment Works (NWWTW) and the New Germany Wastewater Treatment Plant (NGWTP) located in Durban, South Africa were sampled and studied. Details of these treatment plants can be found elsewhere [ 24 ]. The NWWTW and NGWTP discharge their final effluents into the Umgeni and Aller rivers, respectively.…”

Quantitative PCR Detection and Characterisation of Human Adenovirus, Rotavirus and Hepatitis A Virus in Discharged Effluents of Two Wastewater Treatment Facilities in the Eastern Cape, South Africa

“…Presently, the microbiological quality of effluents is still largely assessed by means of faecal coliform in South Africa, while adequate information on the virological quality of discharged effluents is deficient. A number of studies have documented the virological qualities of some freshwater resources in the country (Grabow et al 2004; van Zyl et al 2006; Olaniran et al 2012; Chigor and Okoh 2012) but similar information on the significance and epidemiological importance of enteric viruses from wastewater effluent discharges into the environment have not been fully elucidated. Moreover, environmental surveillance is important in a developing country like South Africa where appropriate system for outbreak reporting and surveillance is deficient.…”

Microbiological, coliphages and physico-chemical assessments of the Umgeni River, South Africa

“…High COD values, which were higher than the water quality target (<10 mg O 2 /l) set for industrial use in South Africa (DWAF 1996a), were also observed in this study suggesting that both organic and inorganic substances from domestic and non-domestic wastewaters are entering these water systems. Olaniran et al (2012) also found high COD values of water samples from municipal sewage plants in this study area. Wang et al (2007) demonstrated that mortality due to liver cancer for men and women was positively correlated with the COD in drinking water in China.…”

“…were detected throughout the study period. These above-mentioned enteric pathogens are commonly identified in water sources (Olaniran et al 2009(Olaniran et al , 2012Kumar et al 2012). The high level of bacterial pollution as well as high THB counts in this catchment area represents a cause of concern.…”