Cullompton is a village with a population of almost 10,000 situated in Devon, England. Our client, South West Water (SWW), identified it as an ideal site to trial a mobile MBBR unit. SWW were interested in the capability of the MBBR in the removal of ammonia. To operate the unit in tertiary mode, influent to the MBBR was taken from the final settling tanks on site at Cullompton. This allowed a comparison between the outgoing flow from the MBBR against the existing treatment comprising of trickling filter beds. After an initial start-up period of around 4 weeks to establish the biofilm within the MBBR unit, routine sampling was conducted by SWW.
The results have been very encouraging, with a consistent reduction by over 90% in levels of ammonia. These results held true even when the flow rate was increased from 3.5l/s to the current 6l/s on site. The MBBR reduced BOD levels by an average of 40%, without any settlement taking place. When settlement occurs, BOD levels are reduced by over 55% on average.
The MBBR unit has now completed its carbonaceous mode trial, to focus on BOD reduction. The BOD results have shown an average of 86% reduction, whilst the ammonia results are also showing over 90% removal. The results for both BOD and Ammonia (NH3) are shown in the graphs below.