Background
Luss is a small village in Argyll & Bute, Scotland, on the west bank of Loch Lomond. The village has its own waste water treatment works which treats approximately 780,000l/day.
Being on the banks of Loch Lomond the site is subject to strict Bathing Water Directive consent limits. In addition, the works see large fluctuations in loading during the peak holiday periods which results in the final effluent quality being inconsistent, particularly with respect to suspended solids, BOD and coliforms.
The suspended solids carry over from the clarifier and then onto the UV disinfection system, which affects it by lowering transmission rates.
The works were failing to consistently meet the requirements for the bathing water directive for suspended solids and BOD.