Sasol converts waste sludge

SASOL is looking to use microbes to turn thousands of tons of waste sludge into compost. The oil and chemical giant said yesterday that it had developed a novel method to transform the potentially harmful trace elements found in industrial waste sludges into an environmentally friendly form. “While composting of domestic sludges is practised worldwide, composting of industrial waste sludges is a unique concept,” it said. The process involved using specialised “microbial populations” of heavy-metal composting bacteria to “target, assimilate and bio-chemically transform the potentially harmful trace elements” found in the sludges. Sasol is using a type of grassy fodder crop called sugargraze. It is then mixed with the treated sludge, transforming it into a compost, which can be used to grow more of the fodder crop. Sasol environmental technology manager Sarushen Pillay said: “We are looking at five waste sludge streams from processes at our Secunda coal-to-oil plant… involving 200 000 tons of sludge a year.” Pillay said the firm hoped to have the project up and running by “the second half of next year”. – Sapa