Boosting performance under high load

Boosting performance under high load

An overloaded municipal treatment works improved effluent quality, reduced solids production and cut operating costs without infrastructure changes.

Challenge

The plant was receiving organic and solids loads well above its design capacity, with poor settleability and limited oxygen transfer.

Solution

ABS worked with the utility to run an eight-month full-scale demonstration, targeting better effluent quality and operational efficiency.

Outcome

Effluent quality improved, solids production dropped, and the site was able to handle more load without breaching consent.

57%

reduction in BOD

40%

reduction in solids

12%

improvement in
settleability

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Details

Improving effluent quality with an overloaded asset

A UK water company faced a significant challenge with a conventional activated sludge asset operating under extreme load conditions, with influent levels at 140% of the design capacity. This treatment plant, designed for a population equivalent of 16,267, had no industrial discharges and was initially within discharge consent. Over the course of 8 months, ABS worked with the utility to operate full-scale demonstrations of Biofermentation® at the plant, working closely to monitor, optimise, and validate the results.
environmental-scientist

“With ABS, we are working to meet our 2030 Net Zero Carbon targets“

Barry Scott

Plant Manager

Performance and Results

Biofermentation® quickly proved its worth in transforming the plant’s performance under stressful conditions. Despite the plant being overloaded, the technology helped boost capacity: 19.7% more BOD and 31.6% more suspended solids were removed, significantly improving the effluent quality. The results were striking: BOD levels dropped by 57%, suspended solids by 46%, and ammonia by 10%. Additionally, the biomass’s settleability improved by 12%, leading to a 40% reduction in solids production, even without fully optimising the system. Operational efficiency also soared, with 40% less polymer usage, 27% less electricity, and 22% fewer biosolid exports.

Benefits to the utility

The plant was able to handle 125% of the BOD load and 143% of suspended solids, all while maintaining better-than-ever effluent quality. The improvements in biomass settleability stabilised operations and provided a clear path for further optimisation. Reductions in solids could potentially exceed 60%, as seen in similar systems in the USA. Even more remarkably, Biofermentation® allowed the plant to achieve revenue-positive outcomes for OPEX without needing any capital expenditure. These gains not only improved the plant’s efficiency but also helped the utility move closer to meeting the UK’s Net Zero Carbon targets by 2030.