Advanced wastewater treatment technology for the plastics recycling industry
- Last updated on 5 December 2024
Background Information
The plastic recycling industry plays an important role in sub–Saharan Africa where waste management systems and facilities are not optimal. Large-scale recycling facilities, not only play an important role in waste management, but provide the impetus for small-scale collection points and buy-back centres and serve as the commercial impetus for local plastics recycling initiatives and clean-ups.
However, plastic recycling is resource-intensive in terms of energy and water use. The process requires intensive initial washing and then re-washing of the plastic waste after flaking. Without specialised filtration, the large volumes of wastewater from the process contain organic and chemical residues, which contribute to chemical oxygen demand (COD) and biological oxygen demand (BOD) as well as heavy metals and microplastics in the wastewater stream, with environmental and human health consequences. Additionally, the water used in the washing process should comply with environmental and human health regulations, such as those put forward by the Kenyan Bureau of Standards (KEBS) as well as the Kenyan Water Act (2016), Water Quality Regulations (2006) and the Public Health Act, to allow these recycled plastic flakes to be sold to plastic re-manufacturers who manufacture and market accredited recycled packaging. As such, wastewater treatment is pivotal in meeting food-grade requirements and cleanliness standards for recycling (food grade) flakes. This poses challenges for the sustainable use of water as wastewater cannot be re-used in the washing process without first being treated to meet these standards.
In an effort to reduce their water use and also achieve environmental compliance for the effluent produced, Nairobi-based Mr Green Africa – one of the largest plastic recycling facilities in Kenya – is installing an innovative on-site effluent treatment plant (ETP) at their facility in Nairobi. The ETP will be used to treat the wastewater resulting from the plastic cleaning processes described above on-site. The ETP will have a combined capacity to treat 12 cubic meters of effluent (12 000 litres) per hour. This will allow the treated water to meet appropriate reuse standards that are aligned with ISO certification and enable the reuse of approximately 80% of the treated water. Together, this will enable increased plastics recycling capacity at the plant to the tune of 70 kilotonnes per annum – five times the current capacity. The increased capacity resulting from the installation of the ETP will facilitate plastics collection and recycling, a critical environmental imperative, and resonates in the livelihoods of 2,500+ waste-pickers in Mr Green Africa’s waste collection network.
Further, the pilot ETP will reduce the amount of microplastics, heavy metals (such as lead) and other process chemicals from detergents and solvents that is released in wastewater effluent. The design of the ETP also effectively concentrates the sludge from the treatment process into the form of cake, making it easier to transport and reducing the cost of doing so.
By applying the cost-saving information and boosted capacity against the capital investment, Mr Green Africa aims to demonstrate the case for water treatment technologies in the plastics recycling industry in Kenya and in Africa more broadly.
Photo credit: Mr Green Africa
Updates
The installation and commissioning of the wastewater treatment plant is complete, with capacity to treat 8 cubic meters of wastewater. The installation of a 4 cubic meter plant is in progress and is expected to be commissioned by the end of the year. This followed mapping the layout for raw and recycled water circulation, as well as wastewater analysis and benchmarking. The treatment plant will cater for the recent five-fold expansion of Mr Green’s recycling facility.
Connect with Mr Green Trading Africa
Websites
Timeframe
Status
Countries of Implementation
Consortium Partners
Sub-contractors:
Biovend East Africa (Equipment design fabricators)
HTP GmbH & Co (Technology consulting partner)
Showcase Resources
Mr Green blog post announcing the pilot project’s launch: Pioneering Change with UK AID Funding: Innovative Wastewater Project