Project Details
| Size | 50 m³/day |
| Location | Sierra Leone |
| Completed | 2023 |
Project Delivery
| Features | Compact wastewater treatment in just one container |
| Treated wastewater is suitable for on-site irrigation | |
| Treatment Modules |
Mechanical pre-treatment |
| Aerated buffer tanks | |
| ClearFox® FBBR | |
| ClearFox® Clarifier | |
| Sludge storage tank |
Project Results
| Before | After | |
| COD | 800 mg/l | 90 mg/l |
| BOD | 400 mg/l | 20 mg/l |
Discussion
Situation
Sierra Leone is a country in West Africa that has large gold deposits. As a result, new mines are regularly built there to extract the gold. Labour camps form around the mines. These camps have their own infrastructure, such as schools, catering facilities and a laundry.
Wastewater treatment also plays a key role in the labour camps. We were approached by the gold producing company to equip a workers’ camp in Sierra Leone with a containerised wastewater treatment plant. Around 50 cubic metres of wastewater are produced there every day, which cannot be discharged into the environment without treatment.
Problem
The challenge in this project was the fluctuating wastewater inflow. Towards the end of a shift in particular, many workers wash themselves, resulting in grey water. This is primarily contaminated with dust and oil. Wastewater is also produced in the camp’s own school, mainly during break times. In the laundry, wastewater is produced evenly throughout the day.
Solution
The best solution for this project was a ClearFox® containerised wastewater treatment plant. This includes a buffer tank, the fixed bed biological process and a lamella clarifier for sludge separation. The PPU also offered UV disinfection of the treated wastewater.
The wastewater first flows into a buffer tank to equalise the inflow peaks. This is ventilated so that no pollutants can settle on the floor. In addition, initial biodegradation takes place as a result. The system then forwards it continuously to the fixed-bed reactor, where the actual biological wastewater treatment takes place. The resulting sludge is separated by a lamella clarifier.
The ClearFox® FBBR process is a highly efficient process for biological wastewater treatment. Microorganisms colonise the firmly mounted carrier material and break down the contaminants in the wastewater. The material is structured in such a way that it cannot be clogged by dust or small solid contaminants. After some time, the microorganisms form a secondary sludge that sinks to the bottom of the reactor.
A lamella clarifier connected to this separates this secondary sludge from the clear water. It uses a physical sedimentation process in which the clear water collects in the upper part of the lamella clarifier and flows out of the system via an overflow. In the process, it passes through a UV disinfection system, which additionally purifies the treated wastewater.
The advantage of the containerised wastewater treatment plant is that it can be easily transported to any part of the world. The plant has been in operation in Sierra Leone since June 2023 and treats the wastewater for the irrigation of the workers’ camp on site.
