Slurry lagoon lining for Wolverhampton farms

Permeable ground under the store

A lot of the farmland around Codsall, Pattingham, Albrighton and Brewood sits on sandstone and light, sandy soils. Those soils are easy to work and quick to drain, which is the problem when slurry is stored on them. An earth-banked lagoon in sand leaks into the ground, and the ground here feeds a principal aquifer.

A welded liner on a protection fleece is the minimum. Where the store sits close to a well, a borehole or a brook, your consultant may specify a double-lined build-up with leak detection, so the lagoon can be shown to be tight instead of assumed to be.

Layer by layer in a double-lined lagoon

A simpler dirty-water store may need only the fleece and one welded liner. Either way, the inlet pipe, the draw-off and the depth marker are each sealed through the sheet, a test weld is made and recorded, and the anchor trench holds the liner at the crest.

• 300gsm non-woven fleece on the prepared formation
• Secondary liner in HDPE or LLDPE, welded panel to panel
• Drainage layer carrying any seepage to an inspection point
• Primary liner welded over the top
• Floating cover, where the design includes one

Digestate as well as slurry

Anaerobic digestion plants in the wider area produce digestate that has to be stored until the spreading season. Digestate lagoons are lined on the same principles, often with a floating cover so rainfall doesn't add volume and odour stays in. We install to the design for the material being stored.

Herd growth and older stores

Farms that have grown their herds often find the old store too small, and a new lagoon goes in beside it. That is a good moment to look at the old one too. An unlined pit dug into sand decades ago may still be in use, and relining it at the same time as the new build means one mobilisation, one set of records and one inspection. It also lets the consultant look at both stores together against what the farm needs to hold.

Earthworks by others, records by us

The banks, the base and the crest trench are built by your earthworks contractor. Before any roll leaves the lorry, we measure those finished slopes and levels against our lining layout, and flag a bank that is too steep or a base that is too stony. At handover you get the QA pack, which sets out the materials, the weld log and the as-built details, ready for an inspection or an insurer.