Encouraging prospects for recycling incinerated sewage sludge ash (ISSA) into clay‐based building products

Abstract

AbstractStaffordshire University has recently completed a laboratory investigation into the potential utilisation of incinerated sewage sludge ash (ISSA) which has now become a serious disposal problem in the United Kingdom. This study involved a physical, chemical and ceramic evaluation of a source of ISSA produced at a newly commissioned sewage sludge incinerator sited near Manchester, initially to establish its level of variability on a day‐to‐day basis. Subsequently, feedstocks from two commercial brick factories both using raw materials of contrasting ceramic properties were obtained to examine the effect of their partial replacement by this source of ISSA. This work programme involved fabricating and firing experimental test‐samples (containing 5% dry w/w ISSA substitution) by the plastic‐extrusion forming method which is employed at both brickworks to manufacture their respective products. Standard ceramic testing procedures were subsequently carried out on the products containing ISSA and compared with those of the normal brick products fabricated in parallel. From the positive results obtained it is believed that the introduction of this source of ISSA as a new raw material for use in brick manufacture potentially offers attractive prospects. Moreover, its application in this identified role would provide an innovative alternative to its current landfill disposal, while also offering a direct contribution towards maximising the conservation of traditional brickmaking raw material reserves.© 2002 Society of Chemical Industry