Improving the removal of phosphate in secondary effluent of domestic wastewater treatment plant

World widely, the excess loads of phosphorus (P) is one of the most common chemical contamination in freshwater bodies (e.g. lakes, rivers). It is one of major causes of eutrophication. In the UK, 80% of 98 surveyed rivers were found to exceed the accepted standard of healthy rivers’ P concentration, e.g. 0.1 mg/L. Effluents from wastewater treatment plant (WWTP) are considered to contribute up to 60–80% of the P in rivers due to discharge of treated effluents containing residual P concentrations of 1–2 mg/L. The discharge level of P from WWTPs in many countries is going to be strictly limited to 0.1 mg/L or even less due to the growing concern over eutrophication. Hence, the alternative technologies are sought to enhance the P removal efficiency from WWTPs. In this study, Ca and Mg incorporated layered double hydroxide (LDH) adsorbents were synthesized and assessed for phosphate removal from both P spiked synthetic solution and real effluent sample of WWTP. The results demonstrated that the effluent from WWTP's secondary treatment process with P concentration of 1.4¿ 5.6 mg/L can be treated by both types of LDH to meet future stringent discharge limit at the level of 0.1 mg/L.