Benhall STW had 2 x Archimedean screw pumps installed at the main inlet that caused many issues, especially with lower bearing failures.
Anglian Waters temporary solution was to hire a diesel driven surface mounted pump, which was coupled to the Bauer connection and to discharge through temporary pipework to the top of the screw pump. Additional pump capacity was provided by “hanging” a submersible pump in the lower part of the screw pump wet well via a davit.
Hydromarque Ltd were asked to attend site to look at an alternative option of using the Gorman- Rupp Super T Series™ self-priming, suction lift, solids handling pump, either as a permanent or temporary solution. The treatment manager for Benhall STW had used these pumps at many sites in the past with great success. The alternatives were to continue with current set up and paying hire charges or remove and replace the bearings on the existing Archimedean screw [est. £150k/pump].
It was agreed to install 1No. 6” Gorman-Rupp Super T Series pump [approx. £9k/set] rated at 60 l/sec to assist the diesel driven set. This was trialled for 1 month in July 2014 and proved successful.
Following the successful trial of the first pump a further set was purchased and all temporary pumps and pipework were removed.
In 2015, Gorman-Rupp launched their new “Eradicator” solids management system for heavy rag applications and both pumps were converted to this system [ Gorman-Rupp Eradicator Solids Management System ].
Following the success of the project, in 2015 Anglian Water decided to replace one of the pumps on the high level inlet pump station on site, again to by-pass the troublesome Archimedean screw pump.
As of October 2021, all pumps are still in and running trouble free.