Sequential batch membrane bio-reactor for wastewater treatment: The effect of increased salinity

• Published in: Bioresource technology Vol. 209; pp. 205 - 212
• Main Authors: Mannina, Giorgio, Capodici, Marco, Cosenza, Alida, Di Trapani, Daniele, Viviani, Gaspare
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2016
• Subjects: acclimation; Biofouling; Biological Oxygen Demand Analysis; Biomass; Bioreactors; Carbon; chemical oxygen demand; Extracellular polymeric substances; fouling; Membrane fouling; Membranes, Artificial; Nitrification; Organic carbon and nitrogen removal; Pilot Projects; respiratory rate; Respirometric batch tests; Salinity; Waste Management - methods; Waste Water - chemistry; wastewater treatment; Extracellular polymeric substances; Respirometric batch tests; Organic carbon and nitrogen removal; Membrane fouling; Salinity
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2016.02.122

•A SB-MBR pilot plant treating wastewater subject to salinity increase was investigated.•Salinity increase influenced the biological contribution of COD removal efficiency.•Salinity increase did not exert a significant stress on heterotrophic bacteria.•Significant reduction of the respiration rates of autotrophic species due to salt.•The irreversible cake deposition was the predominant membrane fouling mechanism. In this work, a sequential batch membrane bioreactor pilot plant is investigated to analyze the effect of a gradual increase in salinity on carbon and nutrient removal, membrane fouling and biomass kinetic parameters. The salinity was increased by 2gNaClL−1 per week up to 10gNaClL−1. The total COD removal efficiency was quite high (93%) throughout the experiment. A gradual biomass acclimation to the salinity level was observed during the experiment, highlighting the good recovery capabilities of the system. Nitrification was also influenced by the increase in salinity, with a slight decrease in nitrification efficiency (the lowest value was obtained at 10gNaClL−1 due to lower nitrifier activity). Irreversible cake deposition was the predominant fouling mechanism observed during the experiment. Respirometric tests exhibited a stress effect due to salinity, with a reduction in the respiration rates observed (from 8.85mgO2L−1h−1 to 4mgO2L−1h−1).