Advanced Water Management Centre

AWMC Seminar Program: Sewer-dosed iron salts, and reducing coagulant usage

A comprehensive laboratory assessment of the effects of sewer-dosed iron salts on wastewater treatment processes (Mario Rebosura)

Abstract: The effects of iron salts used in the sewer system to the receiving wastewater treatment processes is investigated using laboratory-scale wastewater systems comprising sewers, wastewater treatment reactors, sludge thickeners and anaerobic sludge digesters. Two lines were operated and fed with real domestic wastewater as the feed. The experimental line received ferric chloride dosing at 10 mgFe L-1 in the sewer reactor and the control line did not. The effects were assessed through extensive sampling of various units in the two lines. The experimental line displayed reduced sulfide concentration (by 4.3 ± 0.5 mgS L-1) in sewer effluent, reduced phosphate concentration (by 4.7 ± 0.5 mgP L-1) in the biological treatment reactor effluent and reduced hydrogen sulfide concentration in biogas (911.5 ± 189.9 ppm to 130.0 ± 5.9 ppm). The biological nitrogen removal performance of the treatment reactor and biogas production in the anaerobic digester were not affected. However, the dewaterability of the anaerobically digested sludge was enhanced by 19.4 ± 0.2 %. These findings supported our hypothesis that iron dosing to sewers should achieve multiple benefits including sulfide removal in sewers, phosphorus removal in wastewater treatment and sulfide removal in biogas. An integrated consideration should be given to iron salts usage in an urban wastewater system.


Opportunities for reducing coagulants usage in urban water management: The Oxley Creek Sewage Collection and Treatment System as an example (Sirajus Salehin)

Abstract: Upon dosing in sewers, the beneficial multiple reuse of iron chloride (e.g., FeCl2) in downstream wastewater treatment plants (WWTPs) for P-removal in the activated sludge tank and hydrogen sulfide (H2S) control in anaerobic digesters was investigated at a full-scale plant in Brisbane, Australia. Extensive sampling campaigns were conducted before (i.e. baseline period) and during (i.e. experimental period) FeCl2 dosing in the upstream sewers. Our study clearly demonstrated that when FeCl2 is dosed in sewers for sulfide control, it can be reused for P-removal in activated sludge tanks and H2S control in anaerobic digesters in downstream WWTPs, thereby substantially reducing chemical requirements without affecting the treatment performance.

Event Details
Date & Time: 
Friday, 27 April 2018
9am - 10am
Venue: AIBN Building 75, Level 1 Seminar Room

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