Variability study of incinerated sewage sludge ash in relation to future use in ceramic brick manufacture

The prospective use of incinerated sewage sludge ash (ISSA) as a partial replacement for traditional brick-making materials has been previously reported. However; variability in the consistency of the raw materials used in commercial brick manufacture can cause serious production problems. Consequently, to gain market confidence for ISSA in this role, it is essential to establish that its quality is not detrimentally affected either by the nature of the sewage sludge being burned, or as a result of the performance of the incineration process itself. Ash sampling was conducted at a large modern commercial sewage sludge incinerator over a six week period, followed by property characterisation and ceramic evaluation. The results confirm that this source of ISSA is satisfactorily consistent in quality over time, thus verifying its potential for use in brick manufacture on a commercial basis. Recommendations,for additional research to help ensure widespread acceptance are also discussed.