Steady-state model-based evaluation of sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process
Department of Civil Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, Hong Kong; Department of Biotechnology, Delft University of Technology, Julianalaan 67, NL-2628 BC Delft, Netherlands; Water Research Group, Department of Civil Engineering, University of Cape Town, Rondebosch, 7701, South Africa
Recently we developed a process for wastewater treatment in places where part of the fresh water usage is replaced by seawater usage. The treatment of this saline sewage consists of sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process. The process consists of an up-flow anaerobic sludge bed (UASB) for sulfate reduction, an anoxic filter for autotrophic denitrification using dissolved sulfide produced in the UASB and an aerobic filter for nitrification. The system was operated for 500 days with 97% COD removal and 74% total nitrogen removal without withdrawal of sludge. To verify these results and to understand this novel process, a steady-state model was developed from the COD, nitrogen and sulfur mass and charge balances based on the stoichiometries of the sulfate reduction, the autotrophic denitrification and the autotrophic nitrification. The model predictions agreed well with measured data on COD, nitrate and sulfate removal, sulfide production, effluent TSS, and mass balances of COD, sulfur and nitrogen in the three reactors. The model explains why withdrawal of sludge from the SANI system is not needed through comparisons of the predictions and measurements of effluent TSS and phosphorus concentrations. © 2009 Elsevier Ltd. All rights reserved.
Anaerobic sludge; Autotrophic denitrification; Charge balances; COD removal; Dissolved sulfide; Fresh Water; Mass balance; Measured data; Model prediction; Novel process; Phosphorus concentration; Saline sewage; SANI process; Steady-state models; Sulfate reduction; Sulfate removal; Total nitrogen removal; Chemical oxygen demand; Denitrification; Dissolution; Effluents; Forecasting; Nitrification; Nitrogen; Nitrogen removal; Oxidation; Phosphorus; Seawater; Sewage; Sewage treatment; Stoichiometry; Sulfur; Wastewater; Wastewater reclamation; Wastewater treatment; fresh water; nitrogen; phosphorus; sea water; sulfate; sulfide; sulfur; anoxic conditions; autotrophy; chemical oxygen demand; concentration (composition); denitrification; effluent; filtration; nitrification; reduction; seawater; sewage; sludge; steady-state equilibrium; sulfate; wastewater; water treatment; article; autotrophy; chemical oxygen demand; controlled study; denitrification; effluent; filter; nitrification; priority journal; sludge; steady state; stoichiometry; sulfate reduction autotrophic denitirifcation and nitrification integrated process; upflow reactor; waste water management; Acids; Aerobiosis; Anaerobiosis; Autotrophic Processes; Biodegradation, Environmental; Bioreactors; Elements; Filtration; Models, Biological; Nitrogen; Oxidation-Reduction; Oxygen; Phosphorus; Reproducibility of Results; Sewage; Sulfates; Time Factors; Waste Disposal, Fluid