Maximising the benefits of renewable energy continues to be the focus for an increasingly diverse range of companies who have invested in the anaerobic digestion (AD) process and a new bio-energy plant at First Milk’s Aspatria creamery in the Lake District is a good example.
The creamery in rural Cumbria produces award winning cheddar cheese under the Lake District brand and is Europe’s first dairy processing site to feed bio-methane (up-graded biogas) generated entirely from cheese process residues, to the gas grid.
The on-site AD plant is funded and operated for First Milk by Lake District Biogas, which is a separate set by a Scottish project development company, Renewables Unlimited. They commissioned Clearfleau, one of the UK’s renewable energy market leaders, to design, build and operate this innovative bio-energy plant.
Mixing is an essential part of the AD process and SYSTEM MIX Ltd who market the Rotamix Dual Zone Mixing System, have made an important contribution in supplying mixing equipment to numerous projects undertaken by Clearfleau. Early in 2015 Clearfleau undertook the initial upgrade of an existing anaerobic treatment plant at the Aspatria site, prior to starting the new anaerobic digestion plant. The on-site facility is treating the process residues from the cheese creamery and Clearfleau is also responsible for the operation and maintenance of the new bio-energy plant.
Now that the system has been operating for around a year the objective of transforming the creamery operation by maximising the production of biogas has been achieved with some impressive results. For example; the system is generating 5.35 Megawatt hours (MWh) of renewable energy of biogas, is treating 1,650m³ per day of process effluent and whey of biogas, producing around 1,000 Nm³ /hour of biogas, revenue for energy generated from FOTs and RHI of biogas and also reducing costs by cutting fossil-based fuel purchase of biogas.
Why the Mixing Process is Important
As an established supplier of digester mixing systems to Clearfleau and many other private sector food waste AD plants in the UK, System Mix are able to demonstrate that the basis of the success of these plants depends on a durable mixing technology supported by reliable Vaughan Chopper Pumps. Andy Parr, Director of System Mix explains the reasons for the success of System Mix and explains the mixing process in more detail.
“It is crucial to the AD process that suitable pre-conditioning of solids is carried-out prior to digestion and our system has been proven to be one of the most effective in achieving this. The Vaughan pump prevents re-accumulation of fibrous and fatty material in the digester and this means that material continues to pass through the nozzles. This in turn ensures that digestate is adequately conditioned and actually benefits all post-digestion equipment”. He concluded, “As many AD operators now need to maximise the sustainable credentials of their plant and equipment even further, we are confident that the benefits of our mixing systems are becoming even more important as illustrated by the positive results achieved at the First Milk Aspatria Creamery”.