Wasting the Nation.indd - Groundwork
Wasting the Nation.indd - Groundwork
Wasting the Nation.indd - Groundwork
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Chapter 4: The toxic cradle of productionWaste burnt in kilns produces similar emissions to waste burnt in incinerators.Thompson and Anthony note that cement kiln technology has not changed muchsince <strong>the</strong> early 1900s and is not well adapted to “toxic waste destruction”. Moreover,even in <strong>the</strong> European context, <strong>the</strong>y are less rigorously regulated than incinerators:<strong>the</strong>y are allowed to emit more and “have poorer abatement equipment” [2005: 35]. InSouth Africa, cement kilns have operated without any scrutiny from <strong>the</strong> authorities,even after permission was given to burn spent pot linings at some kilns. This changedshortly after <strong>the</strong> confrontation over incineration at <strong>the</strong> parliamentary hearings on<strong>the</strong> Waste Bill. In May, <strong>the</strong> DEAT announced that <strong>the</strong> green scorpions would do a‘blitz’ on cement kilns, heralding <strong>the</strong> start of a ‘clean cement’ campaign. It said <strong>the</strong>cement industry was growing rapidly and might “contribute significantly to pollutionif not mitigated and managed properly”. 87 This is laudable. The suspicion remains,however, that <strong>the</strong> real intention is to head off opposition to waste incineration incement kilns when <strong>the</strong> relevant regulations are put to parliament. In <strong>the</strong> meantime,inspection reports have yet to be made public and it is unlikely that <strong>the</strong>y will reflectnormal operating. The industry was given notice of <strong>the</strong> blitz and will have been on itsbest behaviour. High standards – for example, ensuring complete combustion – costsmoney. It is doubted that <strong>the</strong>y are maintained outside of inspection in Europe and itseems unlikely that <strong>the</strong> local industry will be more assiduous.Toxics generated in <strong>the</strong> kiln, including dioxins and heavy metals, have three placesto go: into <strong>the</strong> air, to <strong>the</strong> dump or into <strong>the</strong> product. The kilns do not producesubstantial solid waste volumes. This is because <strong>the</strong> ash from <strong>the</strong> furnace binds with<strong>the</strong> limestone and o<strong>the</strong>r material inputs to form <strong>the</strong> clinker. Thus, <strong>the</strong> toxic residue in<strong>the</strong> ash is incorporated into <strong>the</strong> product. Where filters are used to reduce emissions ofparticulates (known as cement kiln dust), <strong>the</strong> captured waste is ei<strong>the</strong>r sent to landfill orrecycled through <strong>the</strong> kiln. The latter practice leads to a concentration of heavy metalswhich is ultimately incorporated into <strong>the</strong> clinker. Fur<strong>the</strong>r, ‘extenders’ are added when<strong>the</strong> clinker is milled. During 2006, PPC increased its use of fly ash and limestone asextenders “to conserve nonrenewable resources” and reduce <strong>the</strong> proportion of clinkerin its cement products [PPC 2006: 32]. This would also reduce costs and bulk up<strong>the</strong> product to meet expanded demand. PPC does not say whe<strong>the</strong>r <strong>the</strong> fly ash comesfrom its own plant or o<strong>the</strong>r industries nor does it mention whe<strong>the</strong>r it is tested fortoxic contaminants. From whatever source, however, fly ash is particulate emission87 DEAT media statement, Green Scorpions Embark on Countrywide “Clean Cement” Campaign, May 27, 2008.<strong>Wasting</strong> <strong>the</strong> <strong>Nation</strong> - groundWork - 125 -