Remote locations place particularly high demands on decentralised wastewater treatment. Alongside reliable treatment performance, simple operation, robust technology and minimal dependence on external infrastructure are essential. These requirements shaped a municipal project in South Africa.
A local municipality already operated a treatment plant for domestic wastewater at the site. Its existing settlement tanks remained suitable for continued use. However, other parts of the plant no longer met the operational requirements reliably. The municipality therefore sought a sustainable way to upgrade the existing system.
The plant is located in a remote region. Repairs, spare-part deliveries and technical service visits involve considerable organisational effort and expense. At the same time, municipal wastewater treatment requires a stable process that continues to operate reliably despite an intermittent power supply and limited access to technical support. A completely new plant would have involved unnecessary construction work and additional costs.
PPU Umwelttechnik and its South African partner Wolfwasser developed a site-specific concept for the cost-effective, long-term upgrade of the municipal plant. The project partners deliberately retained and reused the existing infrastructure. Several ClearFox® Nature biomodules now complement the settlement tanks, provide biological treatment and improve operational reliability at the remote site. The municipality has thus combined existing civil structures with modern, completely non-electric treatment technology.
Problem
The existing wastewater treatment plant repeatedly suffered damage to mechanical and electrical components, making reliable long-term operation increasingly difficult. These failures disrupted treatment and increased maintenance requirements. At a remote site, damaged components quickly lead to prolonged interruptions because qualified technicians and suitable spare parts are not always readily available.
The site also experienced an unreliable power supply. Repeated power failures interrupted the treatment process and jeopardised consistent effluent quality. Pumps, blowers and control systems depend on a continuous supply of electricity. When the power fails, essential stages of conventional wastewater treatment stop operating.
The municipality therefore required a robust solution that would provide reliable biological treatment over the long term without vulnerable mechanical or electrical components. The technology had to operate independently of the public electricity grid, reduce maintenance requirements and deliver high-quality treated effluent. The project also required the most economical possible use of the existing plant infrastructure.
Site conditions presented a further challenge. Complex equipment would have required frequent inspections and specialist maintenance. In the long term, this would have increased both operating costs and the risk of further downtime. The municipality therefore needed a passive, resilient process with straightforward operation and very few potential points of failure.
Solution
Several ClearFox® Nature biomodules form the core of the new treatment concept. PPU Umwelttechnik supplied the modules, while Wolfwasser supported their professional installation and integration at the South African site. Together, the project partners incorporated the biological treatment stage into the existing settlement tanks. This approach retained valuable civil infrastructure, shortened the installation phase and significantly reduced investment costs.
ClearFox® Nature treats wastewater entirely without electricity. The system contains no pumps, blowers, motors or electrical controls. It therefore eliminates precisely those components that had previously caused frequent damage and operational interruptions. The treatment process is quiet, odour-free and exceptionally low-maintenance.
First, the existing settlement tanks separate heavy solids from the wastewater, store the settled primary sludge and balance hydraulic peaks before biological treatment. The pre-treated wastewater then flows into the ClearFox® Nature biomodules at a controlled rate. A purely hydraulic distribution system spreads the wastewater evenly across the biological reactors. Overflow structures, baffles, flow controls, tipping devices and perforated distribution boxes regulate the process without electrical drives.
Inside the reactors, microorganisms colonise durable synthetic fibres and specialised fixed-bed media. Their large surface area supports the development of a stable biomass. As the wastewater flows slowly through the different media layers, the microorganisms reliably break down its organic pollutants. This biological process requires neither chemicals nor additional consumables.
Natural air circulation supplies the necessary oxygen. The chimney effect continuously draws outside air through the system. Temperature differences cause the air to expand, cool and contract again. The resulting negative pressure draws in fresh air and supplies the microorganisms with oxygen. The system’s specialised design also prevents unpleasant odours.
The modular concept allows the treatment capacity to match each project’s requirements. Several biomodules operate in parallel and increase the overall capacity. ClearFox® Nature covers applications from four to 50 population equivalents and complies with EN 12566-3. Independent testing confirms the performance of this patented treatment technology.
The South African municipality now benefits from a robust and cost-effective wastewater treatment plant designed for reliable long-term operation. Its non-electric process remains unaffected by power failures. The absence of mechanical and electrical components reduces damage, maintenance work and operational risks. At the same time, integration into the existing settlement tanks avoids extensive new civil works and additional investment.
This project demonstrates how a targeted upgrade preserves and enhances existing infrastructure. Particularly in remote regions, ClearFox® Nature combines reliable wastewater treatment with simple operation and exceptional resilience. The municipality has strengthened its wastewater services for the long term while eliminating dependence on an unreliable power supply.
ClearFox® Nature is suitable for individual homes, small communities and decentralised municipal sites serving up to 50 population equivalents. It offers particular advantages where power supplies are unreliable, spare parts are difficult to obtain or maintenance costs are high. Before designing the system, PPU Umwelttechnik assesses the wastewater volume, influent characteristics, existing infrastructure and applicable effluent requirements.
Yes. ClearFox® Nature requires no pumps, blowers, motors or electrical controls for the treatment process. Hydraulic flows, overflow structures, flow controls and mechanical distribution systems move the wastewater through the plant. Natural air circulation based on the chimney effect supplies the oxygen required for treatment.
Microorganisms colonise specialised synthetic fibres and fixed-bed media with a large surface area. As the wastewater flows slowly through the system, they biologically break down the organic pollutants. Temperature differences generate a natural airflow that draws fresh air into the reactor and supplies the aerobic microorganisms with oxygen. This process is known as the chimney effect.
The absence of electrical and moving components significantly reduces maintenance requirements. Wear-prone pumps, blowers and control elements are eliminated entirely. Routine inspections, checks of the hydraulic distribution system and the removal of primary sludge as required support reliable long-term operation.
Subject to local regulations, the treated effluent is suitable for infiltration into the ground, irrigation or direct discharge into a receiving watercourse. The relevant authorities define the permitted discharge route and applicable effluent limits. Where necessary, PPU Umwelttechnik adds further treatment stages to meet project-specific requirements.
