Comparison of Nereda® and conventional activated sludge systems for industrial wastewater recovery

The growing generation of municipal wastewater due to population growth and industrial development, alongside dwindling fossil fuel resources, calls for renewable energy use. This study is aimed at researching the energy potential of municipal wastewater, comparing three biological treatment systems: the Conventional Activated Sludge (CAS) system and two Aerobic Granular Sludge (AGS) systems based on the Nereda® technology. The study proposed to assess each system's treatment performances, energy consumptions, sludge productions, process stabilities, and economic feasibility for each system. Sampling was performed at three industrial wastewater treatment plants in Iran: a petrochemical complex, a textile factory, and a dairy processing plant. The most significant parameters included COD, BOD₅, total nitrogen (TN), total phosphorus (TP), sludge volume, and indicators of energy efficiency. Microbial analyses using CLSM, and NGS were performed for various purposes, which included the assessment of granule structure and stability. The whole granulation process in the Nereda® system produced stable granules in around ۷۸ days and was able to settle out excellently. With the removal rates of COD >۹۵%, BOD₅ >۹۵%, TN >۹۲%, and TP >۹۵%, it proved to be efficient in pollutant removal, whereas the CAS system had lower efficiencies requiring external carbon addition for denitrification. Energy consumption in the Nereda® system was accomplished with around ۳۰% lesser energy, with ۳۷% less sludge production, and up to ۷۴% reduction in footprint area. The economic and life-cycle analyses indicated that Nereda®, despite initially requiring a higher upfront capital investment, operationally savings are reaped and sludge-handling costs reduced, with a short-term ROI of ۵–۹ years and reduced environmental impact. The study has validated that Nereda® technology constitutes a sustainable and efficient approach for modernizing industrial wastewater treatment in Iran. Considering land constraint, water scarcity, and carbon reduction-goal, its application is recommended particularly for those industries generating a high organic load.

کلیدواژه ها:

Wastewater ، Recovery ، Aerobic Granular Sludge (AGS) ، Nereda® Technology ، Conventional Activated Sludge (CAS) ، Sludge Production