Passive Silt Treatment System
In-ditch Polishing Point
Our bio-engineered In-ditch Polishing Point works within the parameters of existing site infrastructure to create a gravity-fed treatment point for fine, mobilised silt particles, typically generated by clay-rich subsoils.

This passive system requires no pumps or power, making it a low-carbon, low-maintenance solution for controlling silt in ditches, swales, and areas where silty water collects.
Multiple units can be deployed on a site for scalable treatment.
Designed for quick deployment, our In-ditch Polishing Point system is made up of three of our complementary designed products:
- Floc Mat® – a heavy duty mat containing anionic flocculant to bind suspended particles
- Silt Wattle – a permeable barrier that slows the flow and improves treatment
- Silt Mat™ – a 12 kg capture mat that traps fine particles and reduces resuspension
A In-ditch Polishing Point is often used for:
- Construction drainage
- Roadside and rail swales
- Temporary works areas
- Sites with clay-rich or fine soils
- Emergency silt control following rainfall
Key Benefits
We design solutions that work with your site infrastructure and save you money:
Low-carbon, passive treatment
We’ve designed a system that uses no power or pumps to turn large volumes of dirty water, crystal clear to comply with environmental regulations.
Scalable design
Multiple treatment points can be created depending on water quantity, flow and site conditions.
Quick and easy to install
Our In-ditch Polishing Point works with site infrastructure, making use of existing ditches to form a vital part of the treatment system. Watch our installation video to see how easy it is to deploy and dispose of once finished.
Environmentally-friendly design
This product is designed to protect your site and protect the environment. We use robust, biodegradable materials to help minimise waste.
Erosion prevention
This system reduces erosion and prevents bypass flow when installed correctly.
Treats complex sites
This system is effective for treating clay-rich and fine silts that are difficult to manage with other measures.
Technical specification of our In-ditch Polishing Points:
System components | Made up of a combination of popular products (Floc Mat®, Silt Wattle, Silt Mat™) |
Deployment | In-ditches, swales or silty drainage channels |
Installation tips | Download our CAD drawings or watch our installation video |
Fixings (not provided) | Use metal stakes (soft beds) or sandbags (hard beds); two sandbags on leading edge of mats |
Installation Guides
Downloadable PDF
In-ditch Polishing Point Installation Guide
Videos
Videos
Applications
Construction site runoff management
Surface water management is a complex, technical challenge but our innovative solutions help to reduce environmental and non-compliance risks.
Find out moreWater treatment
We work with market-leading technology partners to deliver cost-effective solutions for the treatment of water that also minimises carbon impact.
Find out moreGroundworks
We have a strong track record in supporting groundworkers with products and solutions that balance stakeholder interests with time and budget constraints.
Find out moreQuestion?
Frequently asked questions
Got a question about any of our products or services? Check out our FAQs, or give us a call:
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How are the results used?
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How soon after taking the sample should Frog Environmental receive them?
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How should I package and address samples?
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Can I use tap water?
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What should I send?
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Why is settlement testing important on a construction site?
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What is a Settlement Test?