Everyday household rubbish is being saved from landfill and turned into fuel to help power cement factories in the UAE. Throwaway items such as plastic, paper and food scraps are being collected from households across Ajman and Umm Al Quwain to produce refuse-derived fuel (RDF) – a combustible fuel made of various types of waste.
For every 1,000 tonnes of items collected daily from homes in both emirates, about 80 percent will be converted into alternative energy at the Emirates RDF plant in Umm Al Quwain. The waste is sorted and turned into shredded combustible pieces – or fluff – before being dispatched to the factories.
During a tour of the new waste-to-fuel site on Sunday, the plant’s Dutch manager, Nicolaas de Koning, said the aim is to help cement factories reduce their CO2 production by generating up to 200,000 tonnes of RDF a year. “It will be used in cement factories as a fuel and will partially replace the traditional use of gas or coal,” he said. “Eight hundred tonnes of RDF will replace approximately 500 tonnes of coal, which has an alarmingly high carbon footprint.
“Using this as an alternative energy source has an overall benefit on fuel costs, not to mention the environmental benefits.” The large-scale plant, which should be fully operational later this month and cost $40 million (Dh146m) to build, will convert the waste of more than 550,000 residents in the UAE. The facility was built as part of a joint venture with the Ministry of Climate Change and Energy and Ajman Municipality to improve the UAE’s waste management and it is the first of its kind in the Arabian Gulf. It contributes to the UAE’s strategic objective of landfill diversion of least 75 per cent by 2021.
How is waste converted to fuel?
Two conveyor lines will treat more than 350,000 tonnes of waste a year at the plant and the materials pass through a number of different processes before being converted into the fuel. “We have an industrial shredder that cuts almost any solid waste, from steel to a double bed and wardrobe, into 90mm by 90mm pieces,” said Mr de Koning. “Large magnetic drums segregate ferrous [iron containing] and non-ferrous metals, and they are then separated from the rest of the waste as they cannot be used as high calorific fuel [ [better heating value] for burning.”
Air classifiers then push high-pressured air in the waste and non-combustible parts, such as stones and wet organic waste like banana skins and orange peels, are taken out. “They just don’t burn well so we have to separate them,” said Mr de Koning. “What we’re then left with is a fluff of combustible components which is our end product, the fuel. “The best materials for this type of fuel are paper, plastic, cardboard and woodchips.” If you take one unit of energy [a megajoule] coming from RDF, it should always be cheaper than the same unit of energy coming from coal, said Mr de Koning. While 80 per cent of the waste is turned into fuel on site, about 15 per cent goes to landfill and the remaining five per cent – mainly metals – are sold off.
What materials are used? A laboratory on site allows technicians to check the quality of the RDF before sending it out to factories. Chlorine content, calorific value and moisture are all measured against an industry standard. “The chlorine content has to be under one percent,” said Mr de Koning. “So far, our material is measuring in at about 0.6 percent, which is encouraging. “With our RDF, we are promising 15 megajoules of energy per kilo and the less moisture the better, we aim for under 20 percent. “We tend to take out organic materials like food scraps as they have a high moisture reading.” By implementing this project, approximately 80 per cent of household waste in Ajman and Umm Al Quwain will be diverted from landfill. It will partially contribute to the replacement of traditional fuels such as gas or coal.
(The National)
PHOTO: For every 1,000 tonnes of items collected daily, about 80 percent will be converted into alternative energy. CREDIT: Antonie Robertson / The National.