The N1 City mall in Cape Town, South Africa is pre-empting future regulation changes by making use of organic waste with the aid of installing an anaerobic digester to produce fertilizer.
Growthpoint Properties, which owns the shopping centre, is partnering with Dutch firm Waste Transformers to convert organic waste from operating buildings to landfills in order to produce fertilizer, hot water and electricity.
“Landfills produce methane gas, which is worse for the environment than CO² emissions,” says Gavin Jones, Growthpoint Properties’ Regional Retail Asset Manager for the Western Cape Province.
Jones further added that organic waste material collected from restaurants and food supermarket operators within the shopping centre is place in separate bins and from the recycled goods.
This is processed in the first stage of the machine known as the macerator then chopped up into a usable size.
“A grey water mix is formed and this mixture is then pumped into the anaerobic digester with added enzymes. This digester pretty much functions like a stomach which produces methane gas as well as a by-product of hot water,” Jones said.
According to Jones, the hot water is used to clean the plant and waste areas, the methane is harvested, filtered and kept in the gas component and is used to power an electric generator that feeds electricity back to the mall.
The liquid fertilizer produced by the digester will be used for landscaping by Growthpoint’s properties in the area as well as by non-profit organisations, hospitals and the Parow golf course.
The advantage of this component is that the generator runs the system on its own; hence being a self-sustainable modulated system with a current installation’s capacity is about 6 kVA per day, powering 10 to 11 small shops in the mall.
The main benefit of the system remains in the production of fertilizer, which is a sellable product which we can use in our own property portfolio and begin a micro enterprise to sell this fertilizer into the market.
A case study on the system will be presented at the 19th African Utility Week and Powergen conference at the CTICC in Cape Town in May 2019 while 17 May is set aside for site visit.
Cape Town intends to reduce organic waste going to landfills by 100% by 2027.
