2010 budget for enclosure of Bellozanne Sewage Treatment works (FOI)

​Request

In the draft annual business plan 2010 (P117 / 2009) (amendment 9) lodged by Deputy Fox, a sum of £3 million (£1.5 million in 2009 and £1.5 million in 2010) was allocated to "enclose the Bellozanne Sewage Treatment Works for the purpose of minimizing the odour produced from the site". How much of that was spent and on what? I would like a list of each item the money was spent on and full details of its function.

Response

The draft annual business plan 2010 (P.117 / 2009): Ninth amendment proposed a sum of £1,000,000 towards Bellozanne Sewage Treatment Works – odour control. This sum was allocated in the 2010 Departmental budget, not the £3,000,000 stated in this request.

An odour assessment to determine the odorous operations was carried out at a cost of £31,384. Odorous areas were found to be Biosolids or sludge storage areas, areas of significant turbulence and the sludge thickening plant operation. Findings from this report were considered and then solutions were engineered to be able to eliminate the odours.

As odours were found to be generated predominantly from the sludge processes the £1,000,000 funding was transferred to the Sludge Thickener Project, a £14.3m project.

Two main projects were undertaken to lessen odour generation:

• The covering of specific odorous operations

The sludge storage tanks, which are substantial in size and hold in excess of 3,000 tonnes of sludge, were covered and the odorous air extracted and put through a biofilter to neutralise the odours. Other turbulent areas, such as the inlet works, clarifier feedwells and feedwells into the activated sludge plant pre-screens, were also covered and the odours extracted through filters. The cost of these works was £520,000.

• The relocation of sludge thickening and dewatering facilities into a dedicated odour controlled building.

During these processes odorous biosolids can often spill onto the floor so simply covering these facilities was not deemed an appropriate solution; the preferred solution being to put the facilities into a dedicated odour controlled building. The total cost of the sludge thickening and dewatering facilities was £2,096,373, which was funded by £448,616 from the £1,000,000 and the balance from the Sludge project’s overall allocated funding.