Evaluating Physicochemical Parameters, Heavy Metals, and Antibiotics in the Influents and Final Effluents of South African Wastewater Treatment Plants

The waste generated from antibiotics as influents or effluents in important waters from the rivers over their increased usage is quickly leading to societal health problems. To avoid increased accumulation of these antibiotics and their waste matter, new methods and materials are required to solve the problems before escalation. This paper aimed at evaluating treated wastewater effluent quality of three wastewater treatment plants in South Africa's Vaal Triangle: Sebokeng, Rietspruit, and Leeuwkuil. The influents and effluents were collected and analysed for heavy metals, and eight antibiotic substances for human use (erythromycin, ampicillin, cimethoprim, tetracycline, ciprofloxacin, doxycycline, chloromphemol, and sulfamethoxazol). The physicochemical parameters were also measured and the results showed that Rietspruit influent (Riet IN) had the highest salinity, total dissolved solids (TDS), electrical conductivity (EC), and turbidity. Sebokeng was found to have the lowest values for all the measured parameters except for pH, which was lowest in Leeuwkuil influent (Lee IN). All the antibiotics were below the detection limit in all three wastewater treatment plants (WWTPs), except for sulfamethoxazole. The average concentration of sulfamethoxazole in the influents and effluents for the three investigated WWTPs ranged 39-47.8 ng L-1. The lowest concentrations of magnesium (8.60 mg L-1) and copper (0.054 mg L-1) were found in Rietspruit (Riet MID) and Lee EFF, respectively. Lee IN had the highest concentrations of Na (27.98 mg L-1), K (7.48 mg L-1), Mn (0.249 mg L-1), Cu (0.208 mg L-1), Fe (0.396 mg L-1), Ni (2.271 mg L-1), and Ca (28.60 mg L-1), while Riet IN had the highest Co concentration of 0.324 mg L-1. Sebo EFF and Sebo IN showed 11.82 mg L-1 of Mg and 2.437 mg L-1 of Zn, respectively. The abundance of the metal concentrations follows the order Ca > Na > Mg > K > Zn > Ni > Fe = Pt > Co = Au > Mn > Cu > Cr > As, indicating a higher concentration of Ca as 28.60 mg L-1, while As has the least value, which is 0.053 mg L-1.