UFBAF®: biological treatment for nitrate removal

What is UFBAF®?

UFBAF® is a proprietary MUFO HOLDING SLU technology for the biological treatment of nitrates in water. The design is adapted to the quality and flow rate of the water; UFBAF® is applied to suitable cases and does not replace other technologies needed to treat different parameters.

Operating principle

Under anoxic conditions, microorganisms fixed on a support use a carbon source to convert nitrates into nitrogen gas. After the biological process, post-treatment is applied to ensure the final water quality.

Nitrate removal from water

• Biological denitrification of groundwater and surface water.
• Supply projects that need to reduce nitrates, with a design defined by the analysis and the treatment objectives.

Biological nitrogen treatment in WWTPs

Biofilters can be configured for different stages of the biological treatment of urban wastewater:

• Nitrification: biological oxidation of ammonium to nitrate under aerobic conditions.
• Denitrification: conversion of nitrate into nitrogen gas under anoxic conditions.
• Combined nitrogen removal: integration of nitrification and denitrification to reduce total nitrogen.
• Tertiary treatment and expansion: biofiltration to improve the effluent or increase the capacity of an existing WWTP, depending on the design and available space.

The configuration considers the flow rate, nitrogen load, temperature, available organic matter and the need to add external carbon for denitrification.

UFBAF® has denitrification references. Configurations for nitrification and combined nitrogen removal in WWTPs must be assessed and sized for each project, without assuming that all applications have the same operating references.

Design and performance

Design and performance depend on the water characteristics (nitrate concentration, dissolved oxygen, temperature, other parameters) and on the operating conditions. No results are guaranteed without a prior study of the case.

Reference cases

The Huzhou East New District — Phase II project applies UFBAF® as the basis for denitrification in a municipal WWTP with a design capacity of 100,000 m³/day. See the references and MUFO's scope.

The new EU urban wastewater legislation

Directive (EU) 2024/3019 sets tertiary treatment requirements to reduce nitrogen and phosphorus, with progressive application:

• Plants of 150,000 population equivalent or more: 30% by 2033, 70% by 2036 and 100% by 2039.
• Agglomerations of 10,000 population equivalent or more discharging into areas sensitive to eutrophication or their catchments: 20% by 2033, 40% by 2036, 60% by 2039 and 100% by 2045.

For total nitrogen, the annex sets 10 mg/L for plants from 10,000 to less than 150,000 population equivalent and 8 mg/L for those of 150,000 or more, together with a minimum reduction of 80%. The concentration limit, the percentage reduction or both will apply depending on the applicable requirements.

Transposition must take place before 31 July 2027. Specific application depends on sensitive areas, national legislation and each discharge permit. Biofiltration is an option for studying biological nitrogen removal; on its own it does not imply phosphorus removal or guarantee full compliance.

Commercial models

Depending on the project, supply, rental or an OPEX service can be studied.