A Year in the Life of BV Dairy’s AD Plant
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Transcript of A Year in the Life of BV Dairy’s AD Plant
A Year in the Life of BV Dairy’s AD Plant
AD Update• AD plant signed over March 2011
• All waste produced at the manufacturing plant is treated by the AD plant
• Award winning
kWh Electricity Generation176
27%
Challenges• Running at 45% capacity
• PAS 110 certification, and Biofertiliser properties
• Solids Separation Unit
What went wrong at the AD Plant??
After a night out on the town
We woke up to this
So, what was the cause?
What should happen:– Gas is stored within the dome– Once the dome reaches a
given level, gas is ejected to CHP engine, Flare or Boiler
– If gas pressure within dome increases, the gas will be emitted via the Pressure Relief Valve (PRV)
So, what was the cause?
What actually happen:– Sludge entered the gas line
blocking the path to the CHP/Flare
– The PRV failed– Gas was unable to exit the
dome which resulted in a pressure build up
The outcome of the AD Failure
• One word….EXPENSIVE– All waste/permeate produced from BV Dairy
had to be sent off-site– Digestate had to be removed as Hazardous
waste, as an instant reaction– Increase in waste water treatment– Loss of potential electricity generation– Increased OPRA Scores– Interestingly despite the initial gas release we
didn’t have a single complaint from our neighbours
The Repair
• Two new dome membranes had to be manufactured, which had a 1 ½ month lead time
• The PRV was replaced with an improved design
• Alarms are now in place to alert engineers of the presence of sludge within the catchment pot
Current Situation
• The digester coped with being dormant for two months, with methane being produced within two days of the repair
• Due to strong back up and understanding from the EA and Wessex water we managed to minimise damage to the environment
• Current issues with Digestate disposal and low volumes of incoming waste, The Government needs to look at positioning of AD Plants in the UK
What’s next?!RHI and water saving
85oC
5oC30oC
15oC