A landfill generates leachate that requires reliable treatment before discharge. The existing leachate treatment plant combines several complementary process stages. Alongside biological treatment, the facility uses ozonation. Biological ammonium conversion plays a particularly important role. It addresses a key part of the nitrogen load.
An operational failure took the existing bioreactor out of service. The customer therefore needed a temporary biological treatment system at short notice. The system had to maintain treatment operations and integrate with the existing infrastructure. Purchasing a permanent replacement was not the immediate priority. The customer needed a solution with a flexible rental period.
PPU Umwelttechnik GmbH supplied a pre-owned ClearFox® fixed-bed reactor on a rental basis. The compact containerised system combined rapid availability with straightforward transport and a small footprint. The design basis specified a daily wastewater flow of 30 cubic metres. Actual feed rates reflected operating conditions and the volume of leachate requiring treatment.
The fixed-bed reactor supplemented the existing process equipment. It performed a clearly defined biological function within the overall plant. Renting gave the customer access to a dedicated treatment unit for the required period. It also avoided the immediate capital investment in a permanent replacement reactor.
The failure left a significant gap in treatment capacity. The plant had lost an important biological stage for converting ammonium. The temporary system had to take over this function and work alongside the remaining treatment stages.
Landfill leachate places particular demands on biological processes. Its composition differs from typical municipal wastewater and requires careful assessment of the relevant pollutant loads. Daily operating records from the early operating period showed ammonium nitrogen concentrations of 105–134 milligrams per litre at the inlet to the ClearFox® biological stage. COD concentrations ranged from 252 to 295 milligrams per litre. These measurements cover a limited operating period. They do not characterise conditions throughout the entire rental term.
No comprehensive wastewater analyses were available before the customer placed the order. Specific effluent targets were also unavailable when PPU arranged the rental system. PPU and the customer therefore agreed no guaranteed effluent quality for the fixed-bed reactor. The primary objective was to maintain wastewater treatment operations. The customer monitored water quality as part of its own plant operations.
The situation also demanded rapid delivery. A long-term replacement project would not meet the immediate need. At the same time, the solution had to suit the available space and existing connections. Transport, positioning and integration needed to minimise work on site. Time pressure, wastewater characteristics and existing interfaces therefore shaped the choice of system.
PPU supplied a ClearFox® fixed-bed reactor housed in an insulated 40-foot high-cube shipping container. Four reactor chambers arranged in series provide a total working volume of 50 cubic metres. Fixed polyethylene mesh tubes offer a specific surface area of 150 square metres per cubic metre. Microorganisms colonise these surfaces. The resulting biofilm performs the biological treatment.
Wastewater flows through the reactor chambers in sequence. A membrane diffuser system beneath the fixed-bed media supplies the biomass with oxygen. The stationary media retain the biofilm within the reactor and provide a large surface area for microbial growth within a compact footprint.
Delivery followed just ten days after the budget quotation. The customer unloaded the container by crane and provided the required installation area. It also supplied power and connected the inlet and outlet pipework. Upstream screening to three millimetres protected the reactor from larger particles in the pumped feed.
Operating records documented the establishment of nitrification. Later in the monitoring period, ammonium nitrogen concentrations at the outlet of the ClearFox® biological stage fell below one milligram per litre. COD measurements showed no reduction over the same period. The documented treatment performance therefore relates specifically to ammonium conversion.
Several months into operation, the operator again confirmed reliable nitrification. PPU supported the installation with technical assistance and spare parts. The customer continued using the system beyond the initial minimum rental term. This project demonstrates the value of mobile fixed-bed technology following an equipment failure: a compact rental system rapidly took over a critical biological function and supported the existing leachate treatment plant over an extended period.
This solution suits projects that require biological treatment of landfill leachate, whether to replace a failed bioreactor or supplement existing treatment stages. The key factors are wastewater flow, composition and the required effluent quality. PPU assesses these parameters and designs the appropriate system configuration for your site.
The ClearFox® fixed-bed reactor provides the biological treatment stage. Microorganisms grow on stationary media and treat the wastewater as it flows through the reactor. This project focused on nitrification: the microorganisms converted ammonium into nitrite and subsequently nitrate. Complete nitrogen removal requires an additional, appropriately designed denitrification stage.
Yes. The containerised fixed-bed reactor provides biological treatment during equipment downtime or refurbishment. In this project, it supplemented the existing leachate treatment plant after the original bioreactor failed. PPU tailors the system’s integration and treatment capacity to the requirements of each site.
In this project, delivery followed just ten days after the budget quotation. The lead time for your project depends on equipment availability, the extent of any modifications and site preparations. The biological start-up phase also takes time. PPU coordinates delivery, installation and commissioning around your required deployment date.
For this project, the customer provided a suitable installation area, a crane, a power supply, and inlet and outlet connections. The pumped feed passed through a three-millimetre screen before entering the reactor. For your project, PPU specifies the required connections and site preparations to suit the selected system.
A thorough assessment requires details of daily wastewater volumes, peak flows and existing treatment equipment. Recent analyses—particularly COD, BOD₅, ammonium nitrogen, pH and temperature—establish the wastewater characteristics. PPU also needs your effluent requirements, the available installation space and the intended operating period. Together, these details form the basis of a treatment concept tailored to your project.
