In 2017, GKN Aerospace in Bristol wanted to convert their chromic anodising line into a Tartaric Sulphuric Anodising as per the REACH directive requirement. The challenge was the design of a recycling system working on tartrates and with a strict discharge limit on sulphates.
The new process line comprises 3 recycled rinse tanks, each fed with 12 m3/h of deionised water. In order to achieve this goal, Puretech designed and installed 2 separate recycling systems, based on ion exchange resin, operating in duty/stand-by.
Rinses water is firstly pre-treated via fine filtration filter and UV sterilization to avoid fungus development in the resins vessels or in the process tanks coupled with occasional automatic peracetic disinfection.
Then, each recycling system produces 36 m3/h of deionized water (< 5 μS/cm) and is composed of strong acid cationic resin, weak base anionic resin, strong base anionic resin.
Compact installation with board of automatic valves for resin regeneration.
Effluent from regeneration is sent to a storage tank prior to entering treatment vessel operating on a batch basis.
All treatment steps are performed in the same reactor including coagulation, sulphates and tartrates precipitation, flocculation and settlement. Analysis are performed on the treated water, recorded on the control system before any water can be discharged. Settled sludge are extracted from the bottom of the reaction vessel and dewatered on a filter press.
SCADA – Recycling system
A fibre network has been implemented, to ensure interlocking between effluent plant and recycling plant operations.
Transfer pipework between Process Plant building and ETP is double skinned.
"Puretech Environmental have carried out numerous installation projects at our Washington Campus, each project was carried out to the highest standard. Their attention to detail along with their attitude towards Health and Safety makes them world class in their industry."
