Carbarns WwTW

Project Overview

EPS Environmental Ltd was engaged by Scottish Water Special Projects for the Carbarns WwTW growth project at the project “optioneering” stage. 

This highly reputation scheme was “tipping over” with ammonia consent failure imminent.  As a result Overall Performance Assessment (OPA) was the key driver for Scottish Water and the agreed solution taken forward needed to be robust to ensure buy in from Scottish Water and SEPA and to meet the target Beneficial Use date of March 09.  The process issues / failings included poor PST operation and settling performance, a relatively high spray from the surface aeration process and limited aeration capacity.  Key elements of the solution to the poor settlement comprised replacing the existing SAS pumps, sludge screening plant transfer pumps and supernatant transfer pumps.  A new sludge wastage and settlement process was put in place utilizing existing redundant tanks onsite to promote more efficient settlement and decanting.  The existing Activated Sludge Plant (ASP) was augmented by introduction of a Fine Bubble Diffused Aeration (FBDA) system.  2No 15Kw existing Surface Aerators were powered down and “locked-off” and a new  “drop-in” FBDA system was installed in the first pockets of the ASP.  2No duty/duty 90Kw Blowers were installed to provide oxygen to the process.  Existing MCCs were modified to provide power to new local control panels.   The controls for these new process stages were integrated into the existing communication network between existing site MCCs and PLCs and additional signals transmitted to the telemetry outstation