Advanced wastewater treatment technology for the plastics recycling industry

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 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 project has made significant progress in the design of the ETP as well as preparations for expanding its operations over the past year.

The project plans to pilot an initial 4 cubic meters/hour capacity ETP to determine its efficacy in treating the wastewater effluent, following which an 8 cubic meters/hour capacity ETP will also be installed resulting in a combined capacity of 12 cubic meters/hour. The project has completed its initial wastewater analysis and benchmarking as well as the design and development of the ETP plant. The latter involved numerous engagements with potential vendors for the fabrication and installation of the equipment. These provided the project with key strategic designs, such as installing the wastewater tanks underground rather than on the surface, thereby saving space for the expansion of the facility’s recycling operations. A vendor has been selected and the parts for the ETP have been ordered. However, due to shipment delays from the ongoing conflict around the Suez Canal, the installation of the initial ETP has not yet commenced. This has delayed much of the downstream activities of the project.

Nonetheless, the team is proactively preparing for the arrival of the equipment. They have successfully mapped the final layout for raw and recycled water circulation within the plant for both the initial and the second pilot including the civil works design. They have also made significant progress in expanding their operations, and have realigned warehouse space and acquired an adjacent warehouse to accommodate the anticipated five fold growth.

Connect with Advanced wastewater treatment technology for the plastics recycling industry

Websites

Timeframe

April 2023 – April 2025

Status

Active

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

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