Anaerobic/Aerobic Pretreatment of Sugarcane Mill Wastewater for Application of Drip Irrigation

Because of inappropriate management of sugarcane mill wastewater in Hawaii, odor problems and handicaps to wastewater reuse for drip irrigation and sugarcane washing have developed. Based on the previous work on wastewater characterization and relevant literature review, a combined anaerobic (UASB) and aerobic (EAFB) treatment of supernatant of settled sugarcane mill wastewater for the application of drip irrigation was proposed and investigated. It has been found that the system can efficiently (≥ 99%) remove the organics and solids in wastewater within two days of hydraulic retention time provided. The treated effluent provides better water quality for application of drip irrigation. The alternatives (UASB + EAFB and UASB + AL) were compared based on the net present worth (NPW). It has been found that the combined treatment alternative (UASB + EAFB) for the application of drip irrigation is more cost effective than the alternative of (UASB + AL). Thus, combined (UASB + EAFB) treatment for sugarcane mill wastewater provides not only for the removal of pollution potential, but also for the reuse of the properly treated wastewater for drip irrigation in the land-limited and populated areas.