Improving efficiency in the sludge process at a client site

Our client, who runs several UK holiday parks, was experiencing issues where the Picket Fence Thickener at their site was regularly overloaded due to an ineffective feed arrangement from their three membrane bioreactors. This significantly compromised its solids capture and performance – causing problems to the downstream process from the risk of high biologically active solids entering the balance tank.

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The goal

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This goal was to implement a solution to control the flow from the membrane bioreactors into the PFT to ensure its effective and efficient operation and to prevent septicity, corrosion and odour in subsequent stages of treatment.

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The solution

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Alpheus collaborated with the client and technology provider to develop and design a solution, and control philosophy that would effectively control the flow from the bioreactors, and automate the management of sludge discharge.

The solution involved:

• Installation of a small, dedicated sludge wasting pump, linked to each of the three MBR aeration tanks via actuated valves, which pump sludge from the aeration tanks to the PFT conditioned using existing polymer makeup and dosing system.
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• A sludge blanket detector to alert a high sludge level in the PFT, that would trigger automated discharge of the sludge. This would maximise its sludge thickening capability and prevent solids from entering the downstream process.

Scope of works

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Our skilled Project Engineering team managed the design and implementation of the solution from creating the final designs, through to handover. The scope of the project included:

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• Supplying final designs and control philosophy.
• Procurement and contractor management.
• Modification of existing and installation of new site pipework.
• Installation of new SAS pump, actuated valves and new instrumentation.
• SCADA modifications to integrate the new equipment into the existing SCADA system.
• Produced and supplied full documentation for system use and maintenance.
• Testing and commissioning of the equipment.

Outcome

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The system has been in operation since May 2024, and has been operating effectively since. Matt McGinty, Alpheus Project Manager commented:

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Delivery of this project on a compact site presented some challenges in terms of design and contractor management, which the team addressed skillfully and with strong CDM management. The project was delivered on time, with high safety standards, and the plant was delivering expected performance within a short period.

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