Developing Sustainable Wastewater Treatment Systems Using Biofiltration Process

Treating wastewater is a crucial process to save the environment and provide freshwater conservation tools. This study aimed to develop a sustainable wastewater treatment process based on the biofiltration process. This study experiments employed two of the available local raw materials as filter media for biofiltration to treat the raw wastewater. The Dolomite (CaCO₃, MgCO₃), and Anhydrite crushed rocks (CaSO₄) were selected. The study was performed by constructing two pilot-scale biofiltration systems for 18 operation weeks. A group of wastewater quality parameters of the influent and effluent were tested at different periods of operation such as BOD₅, COD, pH, TDS, EC, cations, and anions: Mg⁺², Ca⁺², K⁺, Na⁺, HCO₃^-, Cl^-, NO^-3, and sodium absorption ratio (SAR). The results showed that both biofilters had high removal rates for BOD₅ and COD a low fluctuation based on period time. It is worth mentioning that the highest BOD₅ and COD removals were achieved in the first 6 weeks using the Dolomite filter reaching 95% and 96% respectively. Moreover, the following treatment using Dolomite showed high-efficiency removals for anions and cations such as Mg⁺² (87.15%), Na⁺ (57.76%), K⁺ (43.6%), Cl^- (77.3%), NO₃^- (92%) and HCO₃^- (63%). Also, the results indicated that the treated wastewater can be reused for irrigation purposes based on SAR which was 1.73. Meanwhile, the Anhydrite biofilter showed a low efficiency of anions and cations removals compared to Dolomite. For instance, the removal efficiency for Mg⁺², Na⁺, K⁺, Cl-, NO₃^-, HCO₃^- were 77.8%, 52%, and 21.1% 36.7 %, 52 % and 61.5%, respectively and SAR was 2.1 epm. In conclusion, the proposed biofiltration systems showed high removal rates for various pollutants from wastewater with some superiority for Dolomite media.