KEE Refurbishment of Packaged Treatment Plants

The Anglian Water Systems (AWS) Team undertook such an exercise over a range of small to medium sized treatment plants adapted by the plc from a local council. Instead of abandoning the existing works, KEE Services Ltd with support from their process partners, KEE Process Ltd, were commissioned to survey 11 sites and report the findings. The report was required to include inventory register, feasibility of refurbishment, process implications and improvements with the associated costs of refurbishment. The survey was undertaken and completed over four weeks and a complete report, with a costed refurbishment program for all the sites was submitted to the AWS Team.

The 11 plants varied from 40PE up to 500PE in size and included systems required to reduce BOD and, in some instances, provide fully nitrified discharge with less than 5mg/l ammoniacal nitrogen. All the plants surveyed were of packaged plant construction, single piece or modular, and included primary settlement stage with combined sludge storage, RBC type biological stage and final settlement tank. The report concluded that it was feasible to refurbish all the plants and included a program for refurbishing the plants to a standard where the operators would have the confidence that the plants would provide a reliable and useful life for a further 20 years. Depending on the extent of refurbishment work necessary, the costs associated with the refurbishment varied substantially, but in every case it was much cheaper than replacement. The cost of refurbishment included for supply and installation of new equipment.

This relates to a cluster of small population equivalent installations where all the plants upgraded were over 20 years old and would now have in excess of a further 20 years life and an improved process performance. With all the sites, the outer GRP structure housing the plant was retained and, with the exception of one or two sites, the internal components including the RBC were replaced by brand new factory built units incorporating the latest concepts in mechanical, structural and process engineering.

All the above plants include sectional GRP covers and were replaced to provide the equivalent of a new plant without the high cost and resource required to build one.

Refurbishing Large Wastewater Treatment Works

The KEE refurbishment concept can also be applied to plants serving larger populations which can be electro-mechanically upgraded to show similar benefits and add 20 years or more useful life to the plant. Scottish Water undertook a similar exercise where an existing 4,750PE activated sludge plant needed to be refurbished to bring the plant back to its full performance requirement without necessarily having to re-build the works.

For more information on Wastewater Treatment Plant refurbishment call KEE Services on: 01296 634500 or visit the KEE Services website.