A by-product of the manufacturer’s wastewater treatment process, liquid sludge was historically collected from the plant and transported offsite six times a week for further processing.
Working with WCS Environmental Engineering (WCSEE), Pilgrim’s engineers explored the possibility of adding an extra stage to the wastewater treatment process to dewater the sludge onsite, reducing the cost of transportation and carbon emissions.
The technical team at WCSEE designed and developed chemical and mechanical treatment options to economically process the sludge, ultimately resulting in a trial installation of Volute Screw Press.
Plug and play system
A 6m containerised unit, constructed off-site, was placed inside the existing processing plant containing everything Pilgrim's UK needed to start processing the sludge.
Pilgrim’s UK site services manager Andrew Hill said, “With the screw press’ plug-and-play capabilities, the team quickly adapted to the technology, and after a five-day trial period, it was decided to extend the trial by directly renting the unit from WCSEE, to further understand the return on investment.”
Dewatered sludge produced at the Spalding site was found to have a potential gas yield that could be used to generate biogas electricity, prompting Pilgrim's UK to send it to the nearest anaerobic digestion (AD) plant. The sludge proved to have such a high gas yield it was valuable feedstock for biogas electricity generation.
Reductions across the board
Since the installation of the screw press, Pilgrim’s UK has seen an 80% reduction in sludge volumes overall and is now only sending dewatered sludge cake from the AD plant once a week on average. The high biogas electricity generation value means the process is operating at zero-cost.
Pete Cranney, technical sales manager at WCSEE, added: “Pilgrim's UK has seen very positive results from its trial, and it has been a privilege to work with the team at the Spalding site, from initial enquiry to delivering dewatered sludge cake on a permanent basis.
“The initial analytics service is offered at no cost to the client, which allows site to prove to themselves the suitability of the technology, the potential cost savings of the project, and the value of the Volute Screw Press as the most attractive return on investment option on the market.”