Berkhamsted Sewage Works - Environmental hopes of many years materialising

For many years the Dacorum Environmental Forum Water Group have been seeking to secure the future of Berkhamsted Sewage Works whilst recognising that several improvements needed to be implemented with regard to the water being discharged into the canal following treatment.

One of our basic objectives is to always seek ways to safeguard the local aquifer and the sewage works contribute to this in a variety of ways. The modern costs of maintaining the high standard related to the quality of the water discharged into the canal might have led to the closure of the sewage works resulting in the raw sewage and untreated water being sent out of Dacorum to Maple Cross, Rickmansworth for treatment. There are many examples of small local sewage works being closed within the Chilterns, ultimately to the detriment of local chalk streams, a globally declining national asset.

Fortunately, Thames Water who are directly responsible for operating the sewage works, together with the Environment Agency who monitor quality of the discharged water, have recognised the importance of maintaining this local facility and have embarked upon a very important period of modernising which incorporates the following:-

· Installing recirculation of effluent to improve the performance of biological filters

· Installing an aeration plant as additional treatment capacity

· A large reedbed area for treatment capacity and to reduce foam at the outfall

· 24/7 monitoring of all influent and effluent.

· Phosphorus levels to be reduced by April 2008 using and iron compound that might reduce weedgrowth in the canal.

The work on the reedbed/wetland area started in November 2007. Lined to prevent effluent soaking into the ground and covering 1.5 hectares this reedbed also will serve to absorb foam particles which has been an eyesore and a nuisance for many years.

Other environmental benefits mean increased levels of cleansed water going into the canal, hence less abstraction from the aquifer by British Waterways which is a very important benefit. All this investment means that we retain the BSW and consequently the treated water rather than it being lost to Maple Cross. The large reedbed will become an important wetland providing an additional resting place for wildfowl on their journey up the valley to the Tring reservoirs.

View of the phragmites reed beds filtering treated water

The discharge point into the Grand Union canal

Author: Roger Hands