HAVER & BOECKER

Reducing microplastics in our waters

Wire mesh stops microplastics before they reach wastewater treatment plants

The environmental damage caused by microplastic emissions is well documented. Microplastics are formed in various ways, including the use and wear of plastic products. That said, eliminating plastic use entirely, whether in private households or industrial operations, is not currently feasible.

That’s why it’s so important to understand how microplastics enter the water system in the first place. Since wastewater treatment plants can’t capture all microplastic particles, many still make their way into the environment.

The best approach? Stop them early.

By using ultra-fine wire mesh filters at the source, microplastics can be intercepted before they ever enter the water cycle, reducing their environmental impact and lowering the burden on downstream treatment processes.

Topics covered:

How microplastics enter the environment
Reducing microplastic emissions with efficient filters
Success factors for effective microplastic filtration

Pathways of microplastics into the environment

A large portion of microplastics enters the environment via water. This happens through rain and wastewater — a mix of sewage, stormwater runoff, and combined sewer overflows. These transport particles into rivers, still waters, and into the soil.

Fragments of roughly 150 different plastic products and composites containing plastics were identified in untreated wastewater, which can be ascribed to the range of macroplastics (>5mm) and large microplastics (1-5mm).

Plastics in the Environment – Initiative of the Federal Ministry of Education and Research [1]

Microplastics can be divided into three types. — Compared to primary microplastics type A (left) and secondary microplastics (right), primary microplastics type B (center) pose the greatest threat, accounting for 66% of emissions.

Types of microplastics and their origin

Industrially produced plastic particles, used in products such as cosmetics (scrubs, shower gels) or in agriculture (encapsulated fertilizers).

Microplastics that occur in industry during the storage or production of plastic products. They are also present in households, where they result from abrasion, weathering, and degradation. In traffic, microplastic particles are generated through tire abrasion.

Plastic particles formed through the breakdown or weathering of macroplastics like plastic bags or bottles (“littering”).

Less microplastic through efficient filters

Engineers and plant designers must develop filtration solutions for municipal wastewater treatment plants. The goal is to remove nearly all microplastic particles from wastewater.

But just as important is the early implementation of barriers that filter these particles before they enter the wastewater stream.

Microplastics from textiles

Textile products are a major source of microplastic pollution. A single household laundry cycle can release up to 700,000 microplastic fibers into wastewater.^[2]

Fine-mesh filters integrated into washing machines can capture the majority of these fibers. These systems often include large-surface sieve plates where ultra-fine wire mesh is bonded to a support grid for added durability. The smooth mesh surface prevents fiber buildup, and with excellent backwash capabilities, these filters also offer long service life and reliability.

Microplastics from tire abrasion

Tire wear during braking, cornering, and accelerating produces microplastics that are carried by wind, erosion, and rainwater runoff into local water systems. Ideally, this contaminated runoff should be filtered before it enters storm drains. Decentralized systems can help.

Examples include roadside drains equipped with cleaning and filtration functions to capture microplastics from stormwater.
Wire mesh plays a key role by retaining coarse debris like stones, leaves, and gravel. When combined with a substrate for capturing fine particles, the mesh also serves as a protective barrier.

Unfortunately, not all rainwater passes through these drains. A significant and largely unmeasured portion seeps into the ground, allowing microplastics to bypass filtration and enter wastewater treatment systems unnoticed.

Efficient wastewater treatment in municipal wastewater treatment plants

Success factors for effective microplastic filtration

For targeted water filtration in household appliances and industrial systems

Flow rate

Square or rectangular mesh typically enables high flow rates. However, selecting the right mesh depends on application-specific factors such as mechanical stability and fabrication options.

Filter Fineness

The mesh type should match the particle size you want to remove. For particles as small as 5 µm, filter mesh is ideal. For coarser separation, square or rectangular mesh may be more appropriate.

Economic efficiency

Wire mesh is known for its strength, precision, and recyclability—qualities that support the development of long-term filtration solutions. Its easy-to-clean surface reduces maintenance needs and operating costs while enhancing overall filtration performance.

_{Sources (November 2022):}

_{^[1] cf. Ecologic Institut gemeinnützige GmbH: "Kernbotschaften" (Key messages), focus of BMBF research "Plastik in der Umwelt" (Plastics in the environment), July 2022, page 16
^[2] cf. Greenpeace: "Mikrofasern aus Kleidungsstücken belasten die Ozeane" (Microfibres from clothing pollute the oceans), February 2021}