Danger! Danger! High Voltage!

Faced with a potential £0.5M bill for a new effluent tank, at a time when future expansion plans were unknown, Meadow Foods has had its dilemma solved at a fraction of the cost by FLI CAP Technology.

The aging 1,250m³ tank was burdened with an old energy-guzzling 110kW blower system that due to breakages wasn’t providing anywhere near the required amount of aeration.

Prolonging the life of the existing tank for at least two to three years would also mean that any new mixing/aeration system would have to be installed ‘live’ as there was no standby tank for redundancy.

And to make the challenge even more complicated, no cranes could be used to fit new equipment due to 11 kilovolt power lines running directly over the top of the tank!

Chris Woods, FLI CAP Technology’s Divisional Director, commented: “Our first reaction, to be perfectly honest was ‘how the hell are we going to do this!’, or words to that effect.

“But after looking at multiple lift-out aeration grids that could work off the existing tank’s floor areas, we chose Landia’s Air Jet system. From previous experience we know that their equipment is super reliable, and backed by their engineers, offers plenty of options with installation, even for very demanding applications.”

At this same Meadow Foods production site, Landia AirJet and also Landia JetMix systems had been working away for seven years on a large balancing tank, without ever causing any downtime. The Landia JetMix works by recirculating the liquid in the tank and creating mixing using the nozzles located in strategic levels in the tank. This provides an even-speed distribution throughout the tank. At the same time, it is possible for the system to create concentrated mixing in specific zones.

Chris Woods added: “We started working closely with the team at Landia on how to best tackle the tricky ‘live and tank full’ installation.

‘The old tank had to remain full’
“With venturi nozzles on each of the Landia chopper pumps that are an integral part of the mixing system, Landia supplied a spike-bottomed guide rail so that the AirJet didn’t need mounting inside the tank. We’d usually much prefer to place the pumps outside the vessel for easy maintenance, but this simply wasn’t possible in this case, because the old tank had to remain full, and didn’t have any flange connections anyway.”

Woods further explained that the guide rail for the Landia aerator can be lifted over the edge of the tank (without any major lifting equipment) and that the spike at its bottom easily secures itself in place. Lifting the units (out on a winch) for maintenance is also straightforward.

He continued: We introduced three 18.5kW Landia units, so less than 60kW in total, replacing a 110kW blower, so the energy savings are considerable. We’ve also set up the AirJet JetMix with fully automated controls, so when set effluent targets have been met, our customer has the option of using just two of the three mixers at certain times, with no drop in aeration levels.

“Costs had also begun to run away with our customer because on top of all the excessive energy being used, they were having to tanker away more than 50% of their inadequately effluent due to its high strength.

‘Prolonging the life of asset’
“The old effluent tank at this site certainly isn’t going to win any beauty contests, but with the right approach, we’ve proved what can be achieved by prolonging the life of asset. Our customer is fully back on track, meeting compliance, removing the costly need for effluent to be tankered away, and drastically reducing their energy usage.

“With the highly efficient Landia AirJet, our customer now has a very reliable, efficient and long-lasting aeration system that provides great peace of mind.”

Dave Hutchinson, Engineering Manager at Meadow Foods, added: “Having previously worked with Chris Woods at FLI CAP Technology, we were confident a cost-effective solution would be found. We were delighted when we were offered Landia equipment, as their systems had been used previously at site for effluent aeration with great success. The quality of the equipment and the management of the installation was superb from start to finish. FLI CAP Technology and Landia delivered a high-quality solution with excellent energy savings too.”