|6 September 2002|
Severe odours at Wastewater Treatment Plant from digesters failure
A failure of the digesters at the Wastewater Treatment Plant in Bromley is causing severe odour release from the plant.
Operations and Maintenance Manager Mike Bourke said that bringing the digesters back to health requires careful nursing of the process conditions and the loads applied to the digesters. This entails storage of some of the raw sludge in the lagoons which is the source of the odour release from the plant at the moment.
The reason for the digester failure is not known for certain, but it seems it may be due to the discharge of a large volume of some material that has caused the upset to the digestion process, said Mike Bourke.
Investigations are continuing to determine the exact cause. Samples have been sent away for analysis, and possible industrial sources are being investigated and sampled.
The strong smells could last for several weeks but should abate after that time, said Mike Bourke. He adds that this situation will not impact on discharge into the estuary as the solids are still being removed. Meanwhile, covers are being placed over the open lagoons to reduce the odour release. To help speed the recovery of the digesters, lime is being dosed into the process to correct the pH imbalance.
Digestion is a biological fermentation process that is susceptible to chemicals which can kill the friendly bacteria in the process. The purpose of the digestion process is to convert the settled solids into a form that make these solids useful as a fertiliser. The process also produces methane gas which is used as a fuel at the plant. The failure of the digestion process causes a reduction in gas production and quality.
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