BENEFICIATION
Interwaste
A solid recovered fuel in the form of fluff, baled and ready for transportation.
Industrial vs municipal waste – a SA perspective
Building on solutions that have already gained traction in the UK and Europe, Interwaste modified the plant according to a local context.
The Interwaste facility follows a different approach to European methodologies, predominantly because industrial clients’ waste streams are purer than municipal waste, which is the standard waste source in Europe used to produce RDF.
“ We are sorting and separating dry industrial waste on our clients’ sites, which is not mixed with any organic matter or moisture-rich content. Therefore, the waste stream is cleaner and thus allows for a simpler shredding and hydration process,” says Aeren Young, environmental scientist at Interwaste.
The RDF plant in Germiston comprises a basic two-step shredding process: from a feeding platform, the waste is transferred by a conveyor to a primary shredder where it is shredded into a sub 100mm size fraction and then moves to the secondary shredder for further processing to a finer size fraction.
The high price of European( especially the United Kingdom) landfill taxes incentivise the public and industry to sort and separate municipal waste streams to an advanced level. Government provides a constructive legislative environment that
encourages and / or rewards the recycling and landfill avoidance of waste.
In South Africa, very little separation happens at source and thus retrieving RDF from MSW is a costly exercise which makes it difficult for the business case to succeed.
High quality fuel source
“ The feedback we are receiving from the Namibian cement producer is extremely positive,” says Young. In fact, Interwaste struggles to keep up with demand.
Ironically, because of the lack of recycling infrastructure and best practice in South Africa, the calorific value( CV) of the RDF is far higher than the RDF produced in Europe. Because municipal waste is wetter than industrial waste, the CV count increases when using the latter as feedstock.
Young says the product Interwaste sends across the border to Namibia has an equivalent CV of A-grade coal.“ The RDF produced and sold to cement kilns in Europe and the UK averages at most 19 mega joules per kilogram. Interwaste is currently producing RDF at about 24 – 26 mega joules per kilogram,” says Willcocks.
Most noteworthy, however, is the fact that the cost benefits of using a wastederived fuel in the production of clinker are substantial.
“ During clinker production, electricity costs amount to 30 – 40 % of cement producers’ operational overheads. If you can provide a
“ Ironically, because of the lack of recycling infrastructure and best practice in South Africa, the calorific value( CV) of the RDF is far higher than the RDF produced in Europe.”
QUARRY SA | JANUARY 2017 _ 23