Experimental and computational analyses for advanced wastewater treatment by volcanic rocks

Treating and reusing wastewater is a promising alternative for the water shortage problem. The advanced treatment of such water can provide a good source for plant irrigation and other applications and reduce the demand for the available freshwater resources. This alternate is highly recommended for arid and semi-arid counties. In this research, volcanic rock (VR) is introduced as an advanced and low-cost treatment option for wastewater. The volcanic rock was adopted as an adsorption tool for removing impurities from the secondary treated wastewater effluents. The study relies on experimental work on a lab scale. Many parameters were investigated such as loose and compacted layered samples, and pretreated methods for the rocks including soaking in clean water or heating for different temperatures. Simulation work also was adopted to validate the experimental results. The study results showed a decline in most physiochemical properties of wastewater after adding VR compared with the control sample. A notable removable for the measurements of the biological oxygen demand and chemical oxygen demand (COD) from wastewater in the presence of VR was observed, which may introduce it as a tool for the advanced treatment of wastewater. The numerical results depicted the experimental data and reflected the effectiveness of the VR-based geomaterial filter for the treatment of wastewater. PRACTITIONER POINTS: Prewashing process for volcanic rock (VR) exhibited an improvement in its removal efficiency ranged between 18% to 98% as for TDS and removal of NO₃ ^- , respectively. Heating samples does not improve the removable properties of VR. A notable removable for biological oxygen demand and COD by 96% and 99%, respectively, for some cases from wastewater, may introduce the VR as a tool for advanced treatment of wastewater. The numerical test results are in consistent with the experimental behavior of the VR and reflect the effectiveness of the VR-based geomaterial filter for the treatment of wastewater.