title: Disinfection of tertiary wastewater effluent prior to river discharge using peracetic acid; treatment efficiency and results on by-products formed in full scale tests.
abstract: This is an investigation of chemical disinfection, with peracetic acid (PAA), in a tertiary sand filter at a full scale activated sludge plant with nitrification/denitrification and P-removal. The reduction efficiency of Escherichia coli and intestinal enterococci in the sand filter is reported. E. coli log reductions of between 0.4 and 2.2 were found with contact times from 6 to 37 min and with dosing from 0 to 4.8 mg L(-1). The average log reduction was 1.3. The decomposition products, bromophenols, chlorophenols and formaldehyde and residual H2O2 were measured before and after the sand filter. The residual H2O2 concentration in the effluent was critical at short contact times and high dosages of PAA due to the discharge limit of 25 μg L(-1). The other three products could not be detected at 0.1 μg L(-1) levels. The chemical cost of PAA dosing is estimated to be 0.039 US$ m(-3) treated wastewater.
authors.affiliation: Aarhus Water Ltd., Bautavej 1, DK-8210 Aarhus V, Denmark E-mail: pop@aarhusvand.dk.
authors.forename: Per Overgaard
authors.initials: PO
authors.lastname: Pedersen
authors.forename: Erling
authors.initials: E
authors.lastname: Brodersen
authors.forename: David
authors.initials: D
authors.lastname: Cecil
mesh_terms: D003718:Denmark; D004202:Disinfectants / Q000737:chemistry; D004203:Disinfection / Q000191:economics / Q000379:methods*; D004926:Escherichia coli / Q000187:drug effects; D005557:Formaldehyde / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D010463:Peracetic Acid / Q000737:chemistry / Q000191:economics / Q000494:pharmacology; D010636:Phenols / Q000737:chemistry; D045483:Rivers; D012722:Sewage; D012822:Silicon Dioxide; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000382:microbiology*
chemical_list: D004202:Disinfectants; D005557:Formaldehyde; D006861:Hydrogen Peroxide; D010463:Peracetic Acid; D010636:Phenols; D012722:Sewage; D012822:Silicon Dioxide; D062065:Wastewater