title: Feasibility of sulfide control in sewers by reuse of iron rich drinking water treatment sludge.
abstract: Dosage of iron salt is the most commonly used method for sulfide control in sewer networks but incurs high chemical costs. In this study, we experimentally investigate the feasibility of using iron rich drinking water treatment sludge for sulfide control in sewers. A lab-scale rising main sewer biofilm reactor was used. The sulfide concentration in the effluent decreased from 15.5 to 19.8 mgS/L (without dosing) to below 0.7-2.3 mgS/L at a sludge dosing rate achieving an iron to total dissolved inorganic sulfur molar ratio (Fe:S) of 1:1, with further removal of sulfide possible by prolonging the reaction time. In fact, batch tests revealed an Fe consumption to sulfide removal ratio of 0.5 ± 0.02 (mole:mole), suggesting the possible occurrence of other reactions involving the removal of sulfide. Modelling revealed that the reaction between iron in sludge and sulfide has reaction orders of 0.65 ± 0.01 and 0.77 ± 0.02 with respect to the Fe and sulfide concentrations, respectively. The addition of sludge slightly increased the total chemical oxidation demand (tCOD) concentration (by approximately 12%) as expected, but decreased the soluble chemical oxidation demand (sCOD) concentration and methane formation by 7% and 20%, respectively. Some phosphate removal (13%) was also observed at the sludge dosing rate of 1:1 (Fe:S), which is beneficial to nutrient removal from the wastewater. Overall, this study suggests that dosing iron-rich drinking water sludge to sewers could be an effective strategy for sulfide removal in sewer systems, which would also reduce the sludge disposal costs for drinking water treatment works. However, its potential side-effects on sewer sedimentation and on the wastewater treatment plant effluent remain to be investigated.
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, QLD 4072, Australia; CRC for Water Sensitive Cities, PO Box 8000, Clayton, Victoria 3800, Australia.
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, QLD 4072, Australia.
authors.forename: Ilje
authors.initials: I
authors.lastname: Pikaar
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, QLD 4072, Australia; CRC for Water Sensitive Cities, PO Box 8000, Clayton, Victoria 3800, Australia.
authors.forename: Keshab Raj
authors.initials: KR
authors.lastname: Sharma
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, QLD 4072, Australia; CRC for Water Sensitive Cities, PO Box 8000, Clayton, Victoria 3800, Australia.
authors.forename: Jürg
authors.initials: J
authors.lastname: Keller
authors.affiliation: Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, QLD 4072, Australia; CRC for Water Sensitive Cities, PO Box 8000, Clayton, Victoria 3800, Australia. Electronic address: z.yuan@awmc.uq.edu.au.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yuan
mesh_terms: D018441:Biofilms; D057919:Biological Oxygen Demand Analysis; D004323:Drainage, Sanitary / Q000379:methods; D060766:Drinking Water / Q000737:chemistry*; D005240:Feasibility Studies; D007501:Iron / Q000737:chemistry*; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010710:Phosphates / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D060766:Drinking Water; D010710:Phosphates; D012722:Sewage; D013440:Sulfides; D014874:Water Pollutants, Chemical; D007501:Iron
keywords: Drinking water treatment sludge; Integrated management; Iron; Sewer odor control; Sulfide