Optimizing Rotating Biological Contactor Technology for Sustainable Wastewater Treatment: A Case Study from North Gaza

Abstract

This study presents an integrated engineering design and performance assessment of a Rotating Biological Contactor (RBC) system for the Phase III expansion of the North Gaza Wastewater Treatment Plant (NGWWTP). The system is designed to meet stringent effluent quality standards while addressing the complex environmental and logistical constraints of the Gaza Strip. Key design parameters include a high influent BOD₅ concentration of 479 mg/L and an average daily flow of 65,700 m³/day. A four-stage RBC treatment scheme was developed and optimized for surface area loading, hydraulic retention time (HRT), and organic removal efficiency. The design achieved BOD₅ effluent concentrations below 14 mg/L, aligning with international discharge standards. In addition, secondary circular clarifiers were incorporated for solid-liquid separation, along with odor control units using biofiltration and full acoustic enclosures for noise-generating components. Compared to conventional activated sludge systems, the proposed RBC configuration offers significant advantages, including lower energy requirements (~500 kW), reduced sludge generation, and a modular setup that improves operational flexibility. Furthermore, clarifier dimensions are approximately 20% smaller, reducing capital expenditure and land use. While technically and environmentally promising, implementation remains dependent on the availability of materials, skilled personnel, and sustained financial support—challenges exacerbated by the blockade and fragile infrastructure. This research demonstrates the viability of RBC systems as resilient and sustainable solutions for wastewater treatment in conflict affected and resource-constrained environments, providing a foundation for decentralized, low-energy wastewater infrastructure in Gaza.