Review Recycling and recovery routes for incinerated sewage sludge ash (ISSA): A review Shane Donatello a,⇑ , Christopher R. Cheeseman b a Department of Cement and Material Recycling, Eduardo Torroja Institute of Construction Sciences (CSIC), C/Serrano Galvache 4, 28033 Madrid, Spain b Department of Civil and Environmental Engineering, Imperial College London, South Kensington SW7 2AZ, London, UK article info Article history: Received 4 December 2012 Accepted 29 May 2013 Available online 29 June 2013 Keywords: Sewage sludge incineration Ash characteristics Pozzolanic cements Phosphate recovery Ceramics Sintered brick and tile abstract The drivers for increasing incineration of sewage sludge and the characteristics of the resulting inciner- ated sewage sludge ash (ISSA) are reviewed. It is estimated that approximately 1.7 million tonnes of ISSA are produced annually world-wide and is likely to increase in the future. Although most ISSA is currently landfilled, various options have been investigated that allow recycling and beneficial resource recovery. These include the use of ISSA as a substitute for clay in sintered bricks, tiles and pavers, and as a raw material for the manufacture of lightweight aggregate. ISSA has also been used to form high density glass–ceramics. Significant research has investigated the potential use of ISSA in blended cements for use in mortars and concrete, and as a raw material for the production of Portland cement. However, all these applications represent a loss of the valuable phosphate content in ISSA, which is typically com- parable to that of a low grade phosphate ore. ISSA has significant potential to be used as a secondary source of phosphate for the production of fertilisers and phosphoric acid. Resource efficient approaches to recycling will increasingly require phosphate recovery from ISSA, with the remaining residual fraction also considered a useful material, and therefore further research is required in this area. Ó 2013 Elsevier Ltd. All rights reserved. Contents 1. Introduction ........................................................................................................ 2329 1.1. Sewage sludge disposal practices in the EU ......................................................................... 2329 1.2. Mono-combustion of sewage sludge ............................................................................... 2329 2. Incinerated sewage sludge ash (ISSA) characteristics ....................................................................... 2331 3. Recycling and recovery options for ISSA.................................................................................. 2331 3.1. Sintered materials containing ISSA ................................................................................ 2331 3.1.1. Sintering studies using ISSA............................................................................... 2331 3.1.2. Bricks, tiles and pavers containing ISSA ..................................................................... 2332 3.1.3. Manufacture of lightweight aggregates from ISSA ............................................................. 2332 3.2. Glass–ceramics containing ISSA ................................................................................... 2333 3.3. Lightweight aerated cementitious materials containing ISSA............................................................ 2333 3.4. Use of ISSA in cementitious materials .............................................................................. 2333 3.4.1. Use of ISSA in the Portland cement manufacturing process ..................................................... 2333 3.4.2. Use of ISSA as an additive to Portland cement ................................................................ 2334 3.4.3. Pozzolanic activity of ISSA ................................................................................ 2334 3.5. Phosphate recovery from ISSA .................................................................................... 2335 3.5.1. Recovery of P by acid leaching ............................................................................ 2336 3.5.2. Recycling of acid insoluble ISSA residue ..................................................................... 2337 3.5.3. Thermal methods of P recovery from ISSA ................................................................... 2337 3.6. Other recycling and recovery options for ISSA ....................................................................... 2338 4. Conclusions ......................................................................................................... 2338 References ......................................................................................................... 2338 0956-053X/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.wasman.2013.05.024 ⇑ Corresponding author. Tel.: +34 913 020 440; fax: +34 913 020 700. E-mail address: shanedonatello@ietcc.csic.es (S. Donatello). Waste Management 33 (2013) 2328–2340 Contents lists available at SciVerse ScienceDirect Waste Management journal homepage: www.elsevier.com/locate/wasman