Biogas Plant Grit Removal System Extracts Digester Grit and Silt from AD Plants By Stephen Last | 04-02-2017 Ever since the first of the current generation of anaerobic digestion plants were commissioned over 15 years ago, a recurrent problem has been the gradual accumulation of inert materials in digester tanks. If it gets into digesters it reduces the reactive volume and gradually builds-up over time, reducing biogas plant efficiency. For some biogas plant operators, the only solution has been to pump out their tanks, and start again. Doing that means a lot of wasted time and revenue. It takes time to remove large quantities of silt, sand, and grit, and re-commission AD plants. This represents a lot of lost biogas production, apart from the cost of the work, and disruption caused to activities on the farm. That’s why we were delighted to be able to publish such good news from Fre-Energy! Read on to find out how you might cure a similar problem in a biogas plant. Fre-Energy’s “Next Generation” Agriculture Describing your highly innovative technology as ‘a slurry tank with a lid on’ is unlikely to win any marketing awards, but with nine successful farm-based AD plants in the UK and a new worldwide patent, Fre-energy’s simple gritremoval system could make it the must-have agricultural installation. Fre-Energy is achieving something unique in the anaerobic digestion and biogas industry, by implementing what can rightfully be called “next generation” agriculture. They are doing this with their unique patented grit and other inert solids removal technology, and successfully combining that with Landia’s well established pumping, mixing and pasteurisation systems, as follows: 1. Fre-Energy’s Patented Technology Prevents the Accumulation of Silt, Sand, Grit Etc Since the development of new technology by Fre-Energy, grit, sand, ash, soil, glass, metal and other inorganic contaminants from the tank do not enter the process at Fre-Energy’s biogas plants. This has proved especially advantageous when using chicken litter as a feedstock, which typically has very high levels of grit. The capability to extract grit and silt also extends to root crops, food waste, slurry from cattle bedded on ash, sand and other high grit inputs. In short, there is never a need to stop the digester to empty it. No downtime. No loss of the heat or power for use on the farm and export to the grid. And, importantly, no health and safety risks associated with the opening of the tank. 2. Landia’s Pasteurizer and Mixers Help as Well In this article we also describe the role of Landia’s equipment at Fre-Energy’s anaerobic digestion plants. True Sustainability – Not Big Numbers Big numbers tend to dominate renewables headlines, with seemingly the more Megawatts being generated the better? – but you won’t find Fre-energy’s name in those news-grabbing figures. Instead, for Welsh organic dairy farmer Richard Tomlinson, his goal when seeking to introduce AD to generate all of his heating and electricity was to complement his farms’ organic milk production – not to create a rural power station. He sought true sustain

Under the umbrella of Fre-energy (Farm Renewable Environmental Energy), Richard's closing of the loop comes in the shape of nine extremely efficient AD plants that support the core business of farming. In addition to the company's de-gritting technology is the highly reliable Landia pasteurization and pumping equipment it has invested in. Combined with dynamic organic waste management and a very efficient slurry management system, the results make a very convincing case for any dairy farmer with over 300 cows to introduce an AD plant as the key to sustaining their business - particularly in rural...

He continued: “I also like the fact that Landia are a long way removed from pump salesmen who'd worry about getting their shoes covered in mud at a farm. Landia understand what we and farming are about - and when necessary won't hesitate to roll up their sleeves to help us". Based on the results in Wrexham, Landia's pumps and mixers now feature strongly in Fre-energy's nine-strong and expanding network of successful farm-based AD plants. Non-headline Energy generation Numbers That Work for Fre-Energy Lodge Farm's small-scale non-headline but totally consistent energy generation is 160kW of electricity...