**2.1 Study areas**

Influents and effluents from six wastewater treatment plants namely; Athlone, Bellville (which consist of the Old and New plants), Kraaifontein, Potsdam, Stellenbosch and Zandvliet) were investigated for the occurrence of seventeen organic compounds (eleven priority phenols and six phthalate esters). Five of these wastewater treatment plants (WWTPs) were located in the City of Cape Town, while one is located in Stellenbosch. Rivers associated with each treatment plant are: Athlone - Vygekraal River; Bellville - Kuils River; Kraaifontein -Mosselbank River; Potsdam - Diep River; Zandvliet - Kuils River and Stellenbosch -Veldwachters River. Five of the WWTPs and associated rivers investigated are presented in Figure 1. Samples were taken at the point of discharge, as well as upstream and downstream from point of discharge (about 1-2km) to evaluate the possible impact of effluent on organic compounds load on the aquatic environment. The geographical location, population equivalent and treatment processes of the investigated treatment plants are presented in Table 1.


Abbreviations: S = Screening; G = Grit removal; Sed = Sedimentation; AS = Activated Sludge; EAAS = Extended Aeration Activated Sludge; N = Nitrogen; BNR = Biological nutrient removal; Chl = Chlorination; UVdis = UV disinfection; AD = Anaerobic digestion; FB = Filter bed; N/K = Not known; WWTP ID = Wastewater treatment plant identification.

Table 1. Description of the six wastewater treatment plants investigated.

Fig. 1. Map showing five of the five of the wastewater treatment plants.
