High-strength wastewater treatment in a pure oxygen thermophilic process: 11-year operation and monitoring of different plant configurations.
This research was carried out on a full-scale pure oxygen thermophilic plant, operated and monitored throughout a period of 11 years. The plant treats 60,000 t y⁻¹ (year 2013) of high-strength industrial wastewaters deriving mainly from pharmaceuticals and detergents production and landfill leachate. Three different plant configurations were consecutively adopted: (1) biological reactor + final clarifier and sludge recirculation (2002-2005); (2) biological reactor + ultrafiltration: membrane biological reactor (MBR) (2006); and (3) MBR + nanofiltration (since 2007). Progressive plant upgrading yielded a performance improvement chemical oxygen demand (COD) removal efficiency was enhanced by 17% and 12% after the first and second plant modification, respectively. Moreover, COD abatement efficiency exhibited a greater stability, notwithstanding high variability of the influent load. In addition, the following relevant outcomes appeared from the plant monitoring (present configuration): up to 96% removal of nitrate and nitrite, due to denitrification; low-specific biomass production (0.092 kgVSS kgCODremoved⁻¹), and biological treatability of residual COD under mesophilic conditions (BOD5/COD ratio = 0.25-0.50), thus showing the complementarity of the two biological processes.
Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 1, 27100 Pavia, Italy E-mail: marco.sordi@unipv.it.
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Collivignarelli
Department of Civil, Environmental, Architectural Engineering, and Mathematics, University of Brescia, via Branze 43, 25123 Brescia, Italy.
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Bertanza
Department of Civil Engineering and Architecture, University of Pavia, via Ferrata 1, 27100 Pavia, Italy E-mail: marco.sordi@unipv.it.
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Sordi
Department of Mechanical and Industrial Engineering, University of Brescia, via Branze 38, 25123 Brescia, Italy.
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Pedrazzani
D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D010100:Oxygen; D012722:Sewage; D064091:Waste Disposal Facilities; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
D010100:Oxygen; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical