Ozonation strategies to reduce sludge production of a seafood industry WWTP.
In this work, several alternatives related to the application of ozone in different streams of a seafood industry WWTP were evaluated to minimize the production of waste sludge. The WWTP was composed of two coagulation-flocculation units and a biological unit and generated around of 6550 kg/d of sludge. Ozone was applied to sludge coming from flotation units (110 g TSS/L) at doses up to 0.03 g O(3)/g TSS during batch tests, no solids solubilization being observed. Ozone doses ranging from 0.007 to 0.02 g O(3)/g TSS were also applied to the raw wastewater in a bubble column reaching a 6.8% of TSS removal for the highest ozone dose. Finally, the effect of the pre-ozonation (0.05 g O(3)/g TSS) of wastewater coming from the first flotation unit was tested in two activated sludge systems during 70 days. Ozonation caused a reduction of the observed yield coefficient of biomass from 0.14 to 0.07g TSS/g COD(Tremoved) and a slight improvement of COD removal efficiencies. On the basis of the capacity for ozone production available in the industry, a maximum reduction of sludge generated by the WWTP of 7.5% could be expected.
Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, Santiago de Compostela, Spain. joseluis.campos@usc.es
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Campos
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Otero
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Franco
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Mosquera-Corral
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Roca
D019649:Food Industry / Q000295:instrumentation*; D007220:Industrial Waste / Q000517:prevention & control*; D010126:Ozone / Q000737:chemistry*; D017747:Seafood; D012722:Sewage / Q000737:chemistry*; D018508:Water Purification / Q000295:instrumentation*
D007220:Industrial Waste; D012722:Sewage; D010126:Ozone