Lightweight Expanded Clay Coverings On Slurry Tanks


Expanded Clay offers a floating covering solution for slurry tanks and lagoons. The main benefits are listed below:

  • Durable and resistant natural clay mineral material without any hazardous or artificial components.
  • Adsorption capacity towards H2S and several other compounds including ammonia and methane so the filter will start removing odour instantly.
  • Up to 80% reduction in hydrogen sulphide emissions
  • Reduced ammonia emission by up to 80%
  • Proven ability to effectively retain nitrogen
  • A 10 cm layer can remove up to 80% of the contaminants

Covering slurry tanks with Lightweight Expanded Clay is an effective method for reducing ammonia emissions and is a requirement for all new storage facilities on installations covered by IPPC.

By installing a layer of Expanded Clay this serves to meet regulatory compliance by handling the residual ammonia that would otherwise be released to atmosphere. The Expanded Clay floats on the surface of lagoons, storage tanks and run off areas to control the release of Hydrogen Sulphide (H2S), Ammonia, Methane and other odours.

Environmental regulations set by DEFRA ensures that the levels of harmful gas released from waste management processes must be reduced to a minimumThe unique properties of Expanded Clay prevents harmful gases escaping into the surrounding countryside – potentially causing damage and pollution to the local area. These initiatives, and targets set by government to reduce gas emissions (including ammonia) and the removal of foul odours of slurry tanks is a major challenge for many farmers.

A quick and simple solution is to pour Expanded Clay directly on top of the slurry, which acts as an effective floating protective cover for a slurry tank or lagoon. A 10cm layer of Expanded Clay poured over slurry limits the emission of harmful gases and foul odours by up to 85%. The Expanded Clay floating cover solution is designed for reducing gas emissions (mostly ammonia) from liquid animal waste.

The lightweight nature of Expanded Clay means that the aggregate simply floats on the surface of the lagoon or slurry tank, making it a cost effective, quick and simple solution in the prevention of harmful gases and odour. The iron oxides in the clay mineral structure acts as a catalyst for chemisorption of Hydrogen Sulphide (H2S), Ammonia, Methane and other organic compounds.

The floating cover solution can significantly reduce the capital costs involved in digestate storage solutions, while offering significant financial returns through the retention of nitrogen. This also reduces the financial costs required for the on-going maintenance required for alternative types of covers such as floating plastic covers and other fixed covers, which depending on the size of the lagoon can be extremely expensive, time intensive and difficult to install.


We recommend using Expanded Clay 10-20 mm and which has a bulk density of 350 kg / m3.


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