Wasting the Nation.indd - Groundwork

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