Globally the need for sustainable waste management solutions is increasing. South Africa is no exception: many of our landfill sites throughout the country are under pressure. In Tshwane, for instance, a number of landfills are under strain and already numerous have closed or will be closing in the next few years.
Waste management company, Earth Probiotic, has heeded the call for a move towards more sustainable waste management practices and has developed a cost-effective and environmentally beneficial in-vessel composting (IVC) machine to combat the challenges of groundwater contamination, air pollution, vermin infestations and public health issues.
Known as the Heron IVC, the machine converts food waste and waste paper/board into compost that can be used for landscaping, agriculture and small-scale food gardening systems. “It employs standard composting techniques – aerating waste to prevent anaerobic conditions, developing the ideal carbon and nitrogen ratio to manage the waste stream, adding probiotic accelerants for speed and elimination of pathogens and leachate management, and the use of recycling systems for environmental compliance – in order to ensure the highest-quality outputs,” explains Earth Probiotic co-founder, Gavin Heron.
A temperature sensor connected to a remote dashboard via Wi-Fi allows for optimum temperatures to be maintained at all times, while an integrated webcam ensures continuous remote monitoring. Weight scales measure all inputs and guarantee that the correct carbon and nitrogen recipe is being implemented, and a bin lifter with load cells automatically calculates waste volumes, guaranteeing a painless process for the Heron IVC’s operators.
Food waste alone generates 335 kilograms per tonne of carbon dioxide equivalent when dumped as a result of the methane it produces. With its ability to produce high-quality compost, the Heron IVC is leading the charge to move away from landfill. It also encourages job creation and leverages local skill sets and capabilities. A feasibility study carried out by consultancy GCS Environmental Engineering revealed that at least four jobs would be created per machine.
GCS’s study took place at the Tshwane Fresh Produce Market, based on the performance of a Heron IVC that was four metres in length and 12 cubic metres in volume area, with a capacity of 30 tonnes per month or a tonne per day. This is the smallest of Earth Probiotic’s composting machines: the company manufactures to specifications of up to 12 metres in length and 36 cubic metres in volume area, with a capacity to process 3 000 kilograms of food waste and 300 kilograms of waste paper per day.
The Tshwane Fresh Produce Market made considerable savings: according to GCS’s calculations, 13 000 kilograms of waste were processed, leading to nearly R13 000 being saved in waste disposal costs and over R2 000 in landfill airspace costs – resulting in an overall saving in excess of R14 000 in just one month. “The technology appears to be more economically feasible than the current system the Tshwane Fresh Produce Market are using (disposal to landfill) and could present a significant cost-saving over the life of the project,” notes GCS consultant Robert Relou. “We have subsequently recommended the deployment of a larger system at the Market to enable the composting of 44 000 kilograms of organic waste each month.”
He explains that moving onto the larger eight-metre-long Heron IVC will enable the processing of 2 200 kilograms of food waste per day, equating to approximately 48 400 kilograms per month – producing 16 cubic metres of compost each month and working out to a 6.3% reduction on current per tonne landfill charges. “This technology has the potential to divert over 580 000 kilograms of food waste produced by the Tshwane Fresh Produce Market from landfill every 12 months, thereby saving over R110 000 over a three-year period and yielding a potential revenue from sales of compost – which compost trials have indicated to be of high quality – at over R174 000 over the three-year period,” points out Relou.
As well as offering substantial financial benefits, both in terms of savings and profit for resale of outputs, GCS found that the Heron IVC facilitates employment opportunities. In fact, for each Heron IVC three new jobs in the green economy will be created. Additionally, the Heron IVC takes into consideration environmental concerns by combatting the damaging effects of dumping and effectively diverting from landfill sites as a waste management solution.