IWRA Proceedings

INTRODUCTION

Pharmaceutical compounds are being reported in groundwater, e.g., in a 1120 locations in 46 States across the USA (Bexfield et al., 2019).  Saudi Arabia has very low rainfall and because of the scarcity of fresh water, wastewater is used for irrigation and artificial recharge of groundwater.  Protecting scarce water resources from potential pollution by pharmaceuticals in Saudi Arabia is essential. This study examined the potential for wastewater from three wastewater treatment plants in Riyadh, Saudi Arabia, to contaminate groundwater with pharmaceutical residues.

METHODOLOGY

• Samples were collected from the influent and effluent of the three WWTPs after chlorination stage.
• Two WWTPs used oxidation ditch treatment and one used trickling filters.
• 144 samples were collected monthly over 12 months.
• 16 compounds selected for analysis and 11 and 5 were detected in the influent and effluent, respectively.
• Percolation through the soil by selected compounds tested in the laboratory (OECD protocol).

CONCLUSIONS

The likelihood of groundwater contamination by the selected pharmaceuticals in wastewater discharged from the three WWTPs would be low due to:

• High removal efficiency in the WWTPs, and
• Low percolation through soil
• Provided the groundwater is protected by an adequate soil layer.

The reuse of effluent for irrigation and groundwater recharge is unlikely to cause environmental risk.

19 January 2023, 09:35 CET