Decentralised Wastewater Treatment Systems
GARBAGE AND OIL INTERCEPTORS
As part of the Nairobi River Regeneration Programme, planned pollution control infrastructure will play a critical role in preventing solid waste and oil-based pollutants from entering the river system. The proposed garbage and oil interceptors, which are yet to be implemented, are designed to address pollution at source and complement ongoing river clean-up, sewerage, and environmental restoration efforts coordinated by the Nairobi Rivers Commission (NRC).
These interventions reflect a shift from reactive clean-up to proactive pollution prevention, ensuring that gains made through regeneration works are protected and sustained over the long term.
Garbage Interceptors
Garbage interceptors are engineered systems designed to capture floating solid waste, such as plastics, debris, and other refuse before it enters or travels downstream within the river. Once implemented, these structures will be strategically installed at key points along the river and its tributaries where waste accumulation is highest, particularly near densely populated areas and stormwater outfalls.
The interceptors will help prevent waste from reaching sensitive river sections, downstream ecosystems, and infrastructure such as bridges and sewer lines. By trapping waste early, they will reduce the burden on downstream clean-up operations, improve water quality, and enhance the overall aesthetics of the river corridor.
In addition, garbage interceptors will support waste management systems by enabling regular collection, sorting, and safe disposal or recycling of captured materials. Their installation will be accompanied by community awareness and behaviour change initiatives to address improper waste disposal at source.
Oil Interceptors
Oil interceptors are specialized treatment systems designed to separate and retain oils, grease, and petroleum products from wastewater and stormwater before is discharged into the river. These pollutants commonly originate from garages, industrial areas, car washes, fuel stations and road runoff.
Once operational, oil interceptors will significantly reduce hydrocarbon pollution in the river, protecting aquatic life, improving water quality and minimizing long-term environmental and public health risks. They will also help prevent the formation of oil films on the water surface, which interfere with oxygen exchange and degrade river ecosystems.
The planned oil interceptors will be integrated into drainage and sewer infrastructure in high-risk locations and aligned with regulatory enforcement and compliance efforts by relevant agencies.
A Preventive Approach to River Protection
Together, garbage and oil interceptors represent a critical preventive layer within the Nairobi River Regeneration Programme. Their implementation will strengthen pollution control, support environmental recovery, and safeguard investments in river training, sewer infrastructure, and community spaces.
The Nairobi Rivers Commission, working with partner agencies and stakeholders, will oversee the coordination, siting, and integration of these systems to ensure they deliver long-term benefits and contribute to a cleaner, healthier, and more resilient Nairobi River Basin.
