Evaluation of the performance of iron-supplemented pelletised compost as packing material in biofilters for odour abatement in domestic wastewater treatment plants

Abstract

Odour emissions from wastewater treatment plants (WWTPs) are a growing concern due to their negative impact on both workers and surrounding communities, with compounds like H2S, NH3 and volatile organic contami- nants (VOCs) contributing to air pollution and potential health issues. Biological technologies, such as biofilters (BFs), are an environmentally sustainable and cost-effective platform for odour control in WWTPs. The use of by- products from WWTPs as packed bed material in BFs would support a circular economy within the water sector. This research evaluates the performance of iron-doped pelletised compost from WWTP sludge by-products as packing material in BFs during the removal of H2S, NH3 and VOCs at empty bed residence time (EBRT). The experimental set-up consisted of three 8-L BFs filled with commercial iron-doped clay pellets (control), pelletised sewage sludge compost and pelletised sewage sludge compost doped with Fe salts. The three BFs achieved a complete removal of H2S and NH3 at EBRTs of 60, 45, 30 and 20 s, while VOC removal exceeded 90 % at EBRTs of 60 and 45 s. The pelletised iron-doped sewage sludge compost supported VOCs removals above 92 % at 60, 45 and 30 s of EBRT. This bed material promoted the growth of genera such as Thermomonas and Thiobacillus among