This identified that the Volute units needed to be raised up 700mm on stainless steel stands to ensure that the existing positive displacement cake pumps feeding the sludge to the THP would not need modification.
During this lead in period KWS Grampian was responsible for removal and disposal of the existing belt presses from the STC building, and this was completed in August 2015. KWS Grampian also assisted with the off-loading of the Volute equipment when it arrived on site and hired in a centrifuge to provide sludge thickening and dewatering, to keep the thermal hydrolysis plant (THP) operational during the project.
Installation of the Volute equipment, into the area previously occupied by the belt presses commenced in September 2015. This included modifications to existing pipework e.g. sludge feed pipework, filtrate drain, washwater, and the improvements to the polymer dosing system (provision of Solitax probes) and was complete by mid-October 2015.
The washwater requirement, to supply the integrated spray bars, was for the provision of 15l/s every 15 minutes per drum (the two Volute units present a total of eight (No.) disc drums), equivalent to 0.5m3/hour. Access platforms and walkways were also provided and installed during this period for inspection of the disc drums and flocculation tanks.
KWS Grampian subsequently undertook the electrical cabling, made all the electrical connections and installed some additional sensors to improve control and set-up interfaces between the PLCs and SCADA to allow control and the exchange of data between the LCP and the main motor control centre (MCC).
This allowed Evergreen Water Solutions to undertake electrical testing and subsequent commissioning, which was completed in December 2015. However, although the units were in use from this time and feeding the THP some subsequent on-site electrical issues had to be resolved and the polymer dosing system set up to suit the requirements of the Volute. These were soon resolved and the process considered to be fully functional during March 2016, allowing full training of KWS Grampian staff to ensue.
Approximately 95% of the Volute plant and equipment was constructed off-site.