Peacehaven WTW and SRC roof plan
Southern Water is obliged to provide primary and secondary
treatment of wastewater arising within the Brighton and Hove
catchment in order to meet the UK’s statutory obligations under EU
Urban Wastewater Treatment Directive (91/271/EEC). The original
proposal to site a new wastewater and sludge treatment works at
Portobello, the site of the existing outfall and headworks, was
refused planning permission on the grounds of unacceptable
environmental impact following planning inquiry. A new team
including Mott MacDonald as engineering consultants was formed in
early 2001 to commence the site selection, feasibility and planning
process with a brief to find the best practical environmental
option (BPEO) for the new scheme.
This project presents numerous challenges to MM in finding
innovative solutions to what is a unique and multifaceted problem.
Planning and environmental constraints in the Brighton and Hove
area include being surrounded by an Area of Outstanding Natural
Beauty (AONB), a proposed National Park, Sites of Special
Scientific Interest (SSSI), and a variety of conservation areas.
These constraints serve to heighten the environmental impact of
development outside the urban areas and by so doing increase the
pressure for development of brownfield sites within the city for
which there already are competing development aspirations. The
result of this is heightened local and national interest in the
scheme.
Portobello underground pumping stationA long
list of 66 potential wastewater treatment works locations was
initially identified by the project team; this was subsequently
reduced to a shortlist of eight, and finally in November 2003, a
preferred site was announced. For all the appraised locations Mott
MacDonald provided engineering design concepts of both transfer and
treatment facilities, operational description to allow appraisal by
the project team and appraisal of the engineering and operational
features of the schemes themselves. Mott MacDonald also provided
engineering outline design of the preferred scheme concept, public
inquiry services and technical services to the procurement
process.
The preferred scheme consists of a compact wastewater treatment
works comprising lamella primary settlement and biologically
activated flooded filter (BAFF) secondary treatment. The sludge
recycling centre will provide digestion and drying in order to
provide a dry pellet product for use as a soil conditioner. The
plant will be designed for a flow to full treatment (FFT) of
2.7m3/s and a population equivalent of around 300,000. Associated
infrastructure works will include the construction of four new TBM
tunnels of total length 10km, three transfer pumping stations and a
new long sea outfall.
