Odour reduction strategies for biosolids produced from a Western Australian wastewater treatment plant: results from Phase I laboratory trials

Abstract

This study investigated sources of odours from biosolids produced from a Western Australian wastewater treatment plant and examined possible strategies for odour reduction, specifically chemical additions and reduction of centrifuge speed on a laboratory scale. To identify the odorous compounds and assess the effectiveness of the odour reduction measures trialled in this study, headspace solid-phase microextraction gas chromatography-mass spectrometry (HS SPME-GC-MS) methods were developed. The target odour compounds included volatile sulphur compounds (e.g. dimethyl sulphide, dimethyl disulphide and dimethyl trisulphide) and other volatile organic compounds (e.g. toluene, ethylbenzene, styrene, p-cresol, indole and skatole). In our laboratory trials, aluminium sulphate added to anaerobically digested sludge prior to dewatering offered the best odour reduction strategy amongst the options that were investigated, resulting in approximately 40% reduction in the maximum concentration of the total volatile organic sulphur compounds, relative to control.

Use of Alum for Odor Reduction in Sludge and Biosolids from Different Wastewater Treatment Processes

“…Therefore the preliminary analysis for VOSCs and odor panel assessment was conducted on samples from WRRFs 1, 2 and 3, while analysis of OVACs was conducted on samples from all four facilities.) All samples were analyzed for the presence of VOSCs (MT, ET, EMS, DMS, DMDS, DMTS and DEDS) and OVACs (toluene, ethylbenzene, styrene, p-cresol, indole and skatole) using our published headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS SPME-GC-MS) methods (Gruchlik et al, 2012(Gruchlik et al, , 2013. The samples were also evaluated by a Curtin Water Quality Research Centre (CWQRC) odor panel.…”

“…Alum Addition to Liquid Biosolids and Processed Sludge Prior to Dewatering. Experiments involving alum addition were conducted in accordance with previously published methods (Gruchlik et al, 2012(Gruchlik et al, , 2013). In the current study, the experiments were conducted in duplicate.…”

“…HS SPME-GC-MS Procedure for the Analysis of Volatile Sulfur Compounds. HS SPME-GC-MS analysis of biosolids and sludge cakes was performed using the analytical method developed in the preceding project (Gruchlik et al, 2012(Gruchlik et al, , 2013. Briefly, sulfur compounds (MT, ET, EMS, DMS, DMDS, DMTS and DEDS) were analyzed by headspace SPME using a 50/30 lm DVB-CAR-PDMS fiber, followed by GC-MS analysis.…”

“…In a preceding study, (Gruchlik et al, 2012(Gruchlik et al, , 2013 we examined potential odor reduction options for anaerobically digested biosolids produced from a metropolitan WRRF which used egg-shaped mesophilic digesters and centrifuge dewatering. The odor reduction methods that were trialed were similar to those described by Adams et al, (2008) and included chemical additions and reduction of centrifuge speed.…”

“…The chemical addition experiments were conducted in the laboratory by adding alum, polyaluminium chloride or ferric chloride to anaerobically digested liquid biosolids prior to dewatering. Of the odor reduction options that were investigated, alum addition to liquid biosolids prior to dewatering was found to be the most promising odor reduction strategy, resulting in a 40% reduction of the peak concentration of total volatile organic sulfur compounds (TVOSCs) relative to a control sample (Gruchlik et al, 2012(Gruchlik et al, , 2013.…”