HAVER & BOECKER

Efficient Wastewater Treatment in Municipal Sewage Plants

Save Time and Energy with Wire Mesh

The availability of drinking-quality water is becoming increasingly important. Efficient wastewater treatment is therefore essential for the responsible management of this valuable resource. Reliable mechanical filtration solutions are indispensable for treating wastewater into drinking water.

In 2022, Germany recorded a wastewater volume of 8.33 billion cubic meters.^[1] This wastewater consists of pollutants from domestic and industrial wastewater, as well as rainwater and extraneous water. Public sewage treatment plants aim to remove these pollutants as much as possible and ensure sustainable water quality.

_{[1] cf. Statistisches Bundesamt (Federal Statistical Office): "Öffentliche Abwasserbehandlung 2022" (Public Wastewater Treatment 2022), October 2024}

Our topics on wastewater treatment

Mechanical wastewater treatment
Microscreen systems – efficient pre-treatment for energy recovery
Success factors for effective wastewater treatment

The first step in wastewater treatment: Mechanical cleaning

Mechanical wastewater treatment in sewage plants forms the first and fundamental step in the purification process, removing up to 30% of organic pollutants.

Initially, coarse impurities are retained by a rake or screen. Sand and grease traps then remove fine solids such as stones or glass shards, as well as oils and fats. Reducing the flow velocity in the primary clarifier allows settleable and suspended solids—such as feces or paper—to sediment.

Mechanical filtration systems play a central role in wastewater treatment: they protect downstream machinery and systems while significantly relieving the biological treatment process in the aeration tank. Here, bacteria and added oxygen break down dissolved organic substances and nutrients.

If needed, chemical treatment is used afterward to remove problematic substances such as phosphates, heavy metals, and salts.

Sketch of a cleaning process in a sewage plant — Image: Illustration of a typical municipal wastewater treatment process

Microscreen systems – efficient pre-treatment for energy recovery

Modern wastewater treatment increasingly relies on microscreen systems to utilize sewage sludge as an energy source. This helps offset a significant portion of the energy required for the treatment process, which is extremely high.

The microscreen system pre-cleans wastewater in the treatment plant, filtering out a maximum amount of solids before the actual purification process begins. These solids can be used in biogas plants to contribute to energy generation.

To meet these requirements, microscreen systems must have a high filtration precision while also withstanding mechanical and chemical stresses.

Mechanical stresses mainly result from regular high-pressure cleaning and the cavitation effect, caused by alternating overpressure and underpressure conditions.

Section of a micro screen with wire mesh — A wire mesh filter medium can be easily integrated into existing systems.

The filter element depends on the system design

Wire mesh wastewater filters can be easily integrated into existing wastewater treatment plants—as filter candles, flat sieve mesh, or filter plates.

Regardless of the filter type, the following properties ensure optimal utilization of microscreen systems:

Ultra-fine pore sizes to retain organic suspended solids, fine particles, bacteria, sand, and even the smallest microplastics
Maximum flow rates and minimal pressure loss despite fine pores
Optimal dirt absorption and cleaning capability
Stability and corrosion resistance

Success factors for effective wastewater treatment in sewage plants

Throughput

Cleaning the filters typically involves mechanical and chemical stress. Optimizing cleaning intervals depends on achieving the ideal balance between flow rate and dirt absorption.

Filter fineness

A large proportion of organic suspended solids, bacteria, sand, and microplastics can be removed using twilled weave or laminated wire mesh.

Material selection

Corrosion resistance is undoubtedly essential for any filter in contact with water. Equally important are the welding properties of the material, as pre-assembled filter elements are often kept in shape through welding.