Mixing is one of the most critical stages in maximising the efficiency of today’s Anaerobic Digestion (AD) processes and the ROTAMIX system has become established as the preferred choice of AD mixing systems at numerous waste water sites across the UK. Developed by Vaughan Co and supplied in the UK by solids pumping and mixing specialists SYSTEM MIX (a subsidiary of P&M PUMPS Ltd the UK’s distributor for Vaughan Chopper Pumps), the Rotamix system is now also being successfully utilised by an increasing number of the UK’s Energy Recovery Facilities (ERF’s).
Where Rotamix has yet to be adopted as the primary means of mixing digesters existing (or new), less effective mixing technology is being enhanced by the use of Vaughan Chopper pumps for heat exchanger re-circulation applications. Reliable performance and optimum temperature distribution is paramount to the success of the digestion process. Heat exchangers remain clean and free from blockages due to conditioned (chopped) sludge being re-circulated at steady pressure and flow conditions.
Efficient operation of heat exchangers within the process is vital to ensuring gas production and solids reduction is maintained. The key reasons for this success is that by using the Vaughan Chopper pump, blockage-free performance of heat exchangers is ensured where fibrous materials would normally foul them reducing their efficiency.
A recent example of this is the receipt of an order from Murphy Process Engineering to supply 4 x Vaughan model HE8K-305 55Kw horizontal end-suction chopper pumps for the expansion project at Yorkshire Waters’ Huddersfield ERF plant for digester heat exchanger re-circulation. This follows successful ERF projects at Blackburn Meadows, Sheffield in 2012 and Knostrop, Leeds in 2017, where Vaughan Chopper pumps were selected for similar duties.
Initially, utilising Vaughan Chopper pumps for heat exchanger re-circulation applications was one of the forerunners of the highly successful and universally accepted Vaughan Rotamix jet-mixing systems. There are numerous examples of this in the UK including Anglian, Thames and Southern Water, primarily for digester and sludge tank mixing.
Andy Parr, Director of P&M Pumps says, “By being approved to supply our pumps to Yorkshire Waters’ Huddersfield site is testament to the performance of Vaughan pumps at Knostrop and Blackburn Meadows. Since the pumps were originally installed up to 7 years ago (at Blackburn Meadows) we have not needed to supply any wet-end spare parts to either the Blackburn Meadows or Knostrop sites. This illustrates that the simple, rugged design and hardened materials of construction of the Vaughan pump are the key factors in why the pump has secured and maintained its position as the market-leading pump in its field”.
The UK government has set ambitious targets for zero food and packaging to landfill in the future which will in part, be significantly affected by access to technology that contributes to reducing a reliance on carbon based fuels and reducing emissions. System Mix are therefore excited about the potential for solving problems associated with disposing of organic waste materials for energy generation by the process of anaerobic digestion. Having worked closely with most of the UK’s water companies on numerous AD mixing projects to the extent that several major works have become energy self-sufficient by the use of their own excess gas production with the help of reliable and efficient mixing.
System Mix is therefore confident that their knowledge and experience will continue to deliver systems that ensure optimum performance over the life of the plant.