Aerotop Covers

Harmful Gas Emission & Odour Control Solution


Floating cover solution for slurry tanks and lagoons

Leca® Aerotop is an innovative ceramic bulk material that can be added to the surface on a slurry tank or lagoon to form a floating layer (See image). Leca® Aerotop is a product that tackles the issue of odour at their source and has been proven to significantly reduce harmful gas emissions. This innovative material 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* (See Fig. 1 Study Table).


The Scientific Innovation of Leca® Aerotop

The gas emission removal system is created by a catalyst reaction on the Leca® Aerotop surface, which contains iron oxide and other metal oxides. This means that the emission removal solution and performance will last – preventing the release of harmful gases and odour into the surrounding area.

The lightweight nature of Leca® Aerotop 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 Leca® Aerotop floating cover solution can significantly reduce the capital costs involved in digestate storage solutions, while offering significant financial returns through the retention of nitrogen. Leca® Aerotop 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.


Innovative and Quick Delivery Methods

We have accumulated a wealth of experience over the past 20 years in successfully transporting and delivering Leca® Aerotop to diverse agricultural projects throughout the UK and Ireland. Depending on the project, we can source the vehicles that best suit the project requirement. This also includes the popular and innovative pneumatic blowing delivery (see image below) which can deliver Leca® Aerotop in difficult terrain and can be blown in at a distance of up to 40 metres allowing for greater flexibility and aiding environmental consideration to a variety of access and constructional challenges. This can be pneumatically delivered to provide immediate coverage to a lagoon. Another popular method of delivery is through tote bags (2.2m3 volume), which again make it easy to transport onto site.


How can Leca® Aerotop help?

Leca® Aerotop is the only lightweight aggregate with a granularity of 10-20 mm and has a bulk density that does not exceed 300 kg / m3. As suggested by the Department for Environment Food & Rural Affairs (DEFRA), in the Government document ‘Code of Good Agricultural Practice (COGAP) for Reducing Ammonia Emissions’(page 8), using lightweight expanded clay aggregate as a floating cover solution can provide an effective protective layer against dangerous emissions including Hydrogen Sulphide (H2S), Ammonia and Methane into the surrounding environment.

Cost effective, Simple and Quick solution

Manufactured by Leca in its unique kilns (See Image below), Leca® Aerotop is a Lightweight Expanded Clay Aggregate that offers many fundamental properties which make it a perfect solution for lagoon cover.

Leca® Aerotop is a flexible and quick solution helping to reduce the build-up of crusting. A 10cm layer of Leca® Aerotop poured over slurry limits the emission of harmful gases and foul odours by up to 85%* (See Fig. 1 Study Table).


Valuable Nutrient Protection

Digestate is as valuable a commodity to British farming as spreading helps return to the land nitrogen, phosphate, potash and sodium. All four of these are important to the agricultural industry and for the future of British farming.

Legal Obligations for Farmers and Anaerobic Digestion Plants
Ammonia and odorous gases are produced by microbial activity in slurry, these gasses rise to the top of the surface and are released into the atmosphere at varying rates. The reduction in gas emissions (including ammonia and H2S) and in the removal of foul odours of slurry tanks is becoming a major legal challenge for many farmers. There are a number of techniques available to farmers and digestion plant owners. However, many of these solutions have been found to be expensive and unfit for purpose. This is where Leca® Aerotop offers an innovative and proven solution (See Wrexham Bio-Gas Digestate Lagoon Case Study)

The benefits of utilising Leca® Aerotop on a slurry tank includes:

  • Stable structure – does not degrade or collapse
  • Durable and resistant natural clay mineral material without any hazardous or artificial components.
  • Quick pneumatic installation available
  • Lightweight nature means reduced construction costs, filling and removal costs.
  • Well defined product grading (10-20mm).
  • Leca® Aerotop has sorption 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.* (See Fig. 1 Study Table).
  • Reduced ammonia emission by up to 80%* (See Fig. 1 Study Table).
  • Complies with EU Standards and BAT guidelines (Best Available Techniques)
  • Reduces carbon dioxide and other vocs* (See Fig. 1 Study Table)
  • No expensive roof or permanent cover required
  • Proven ability to effectively retain nitrogen.
  • A 10 cm layer can remove up to 80% of the contaminants
  • Long lasting floating lifetime*

Leca® Aerotop Environmental Life Cycle

Leca® Aerotop offers an environmentally friendly floating cover solution. It uses no plastics in its construction and can be spread on the land at the end of its usable life. Leca® Aerotop innovatively rises and falls with digestate levels and allows for easy access to the digestate, this is essential for good digestate handling practice and regular agitation.

Fig. 1 Study Table