Petrochemical and chemical wastewaters contain a great variety of contaminants needing different treatments for their removal. In recent decades, regulations for the final discharge of industrial wastewater treatment plants (WWTPs) have set more and more stringent limits for macro- and micro-pollutants, requiring upgrades to existing WWTPs. This paper examines the interventions at the WWTP for the petrochemical site of Porto Marghera, near Venice, Italy. Due to extremely severe legal limits and bare available areas for plant upgrading, the existing Conventional Activated Sludges (CAS) tank was converted into a Membrane Biological Reactor (MBR). In this way, the increased sludge retention time (SRT) enhances nitrification and biodegradation, bioaccumulation and mineralization of the more persistent compounds and the passage through the ultrafiltration membrane guarantees a full solid-liquid separation. An analysis of the different forms of nitrogen in the treated wastewaters showed significant amounts of dissolved and recalcitrant organic nitrogen. The limit of 10 mg L-1 for total nitrogen (TN) is met by the combined means of a membrane filtration, which removes the organic nitrogen discharged with the sludge flocks, and a post-denitrification.
Nutrients Removal Upgrading at a Petrochemical Industrial Wastewater Treatment Plant: the case of Porto Marghera, Venice, Italy
MASOTTI, Luigi;VERLICCHI, Paola;
2009
Abstract
Petrochemical and chemical wastewaters contain a great variety of contaminants needing different treatments for their removal. In recent decades, regulations for the final discharge of industrial wastewater treatment plants (WWTPs) have set more and more stringent limits for macro- and micro-pollutants, requiring upgrades to existing WWTPs. This paper examines the interventions at the WWTP for the petrochemical site of Porto Marghera, near Venice, Italy. Due to extremely severe legal limits and bare available areas for plant upgrading, the existing Conventional Activated Sludges (CAS) tank was converted into a Membrane Biological Reactor (MBR). In this way, the increased sludge retention time (SRT) enhances nitrification and biodegradation, bioaccumulation and mineralization of the more persistent compounds and the passage through the ultrafiltration membrane guarantees a full solid-liquid separation. An analysis of the different forms of nitrogen in the treated wastewaters showed significant amounts of dissolved and recalcitrant organic nitrogen. The limit of 10 mg L-1 for total nitrogen (TN) is met by the combined means of a membrane filtration, which removes the organic nitrogen discharged with the sludge flocks, and a post-denitrification.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
