Water Journal : Water Journal March 2011
refereed paper sewer processes water MARCH 2011 91 one without any chemical dosing. The cost of P removal in the WWTP includes the cost of FeCl3 currently being dosed and associated maintenance costs. Without considering the impact on WWTP, oxygen is the most cost effective option. Once the impact on WWTP is included, the operational cost for oxygen increases, as an extra carbon source is needed to improve the N removal performance. Thus ferric chloride becomes the most cost- effective option, as Fe3+ can be re-used to precipitate phosphate without the need of ferric dosing in the treatment plant. Conclusions This paper presents a methodology of investigating the impacts of chemical dosing in sewer networks on N and P removal in WWTP. Current practice of selecting the chemical dosing based on the effectiveness on sulfide control doesn't yield optimal solutions, as the impacts on the performance of WWTP are completely ignored. This study demonstrates the need for integrated modelling of sewer systems and wastewater treatment plants for the assessment of the options of chemical dosing in sewers. Sewer and WWTP models have been illustrated as valuable tools for optimal sewer management. Acknowledgement The authors would like to thank Gold Coast Water for their financial and technical support. The Authors Dr Keshab Sharma (email k.sharma@ uq.edu.au), Professor Jurg Keller and Professor Zhiguo Yuan are with the Advanced Water Management Centre, University of Queensland. Dr Oriol Gutierrez is with the Catalan Institute for Water Research, ICRA, Girona, Spain, and was with the Advanced Water Management Centre at the time of this study. Shaun Corrie, Kelly O'Halloran and Bill Capati are with Allconnex Water, Gold Coast, Qld. References: Bhuiyan MIH, Mavinic DS & Koch FA (2008): Phosphorus recovery from wastewater through struvite formation in fluidized bed reactors: a sustainable approach. Water Science and Technology, 57(2), pp 175-181. Corre KSL, Valsami-Jones E, Hobbs P & Parsons SA (2005): Impact of calcium on struvite crystal size, shape and purity. Journal of Crystal Growth, 283, pp 514--522. de Haas DW, Sharma K, Corrie S, O'Halloran K, Keller J & Yuan Z (2008): Odour control by chemical dosing: a case study. Water (Journal of AWA), 35(2), pp 138-143. Gutierrez O, Park D, Sharma KR & Yuan Z (2010): Iron salts dosage for sulfide control in sewers induces chemical phosphorus removal during wastewater treatment. Water Research, 44, pp 3467-3475. Henze M, Gujer W, Mino T & van Loosdrecht M (2000): Activated Sludge Models ASM1, ASM2, ASM2d and ASM3. IWA Scientific and Technical Report No. 9. IWA Publishing, London, UK. Sharma KR, Yuan Z, de Haas DW, Hamilton G, Corrie S & Keller J (2008a): Dynamics and dynamic modelling of H2S production in sewer systems. Water Research, 42, pp 2527-2538. Sharma K, de Haas DW, Corrie S, O'Halloran K, Keller J & Yuan Z (2008b): Predicting hydrogen sulfide formation in sewers: a new model. Water (Journal of AWA), 35(2), pp 132-137.
Water Journal April 2011