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Position Statement by Anglian Water

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Position Statement by Anglian Water

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									Position Statement by Anglian Water


          Cambridgeshire and Peterborough
  Minerals and Waste Local Development Framework

                 Preferred Options

  Relocation of Milton Waste Water Treatment Works
             Area of Search at Honey Hill




                 6 November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

INTRODUCTION


1.        Anglian Water is geographically the largest water company in England and Wales
          and serves 2.6 million properties across East Anglia and the East Midlands. The
          Anglian Water region covers some 27,500 square kilometres stretching from the
          Humber in the north to the Thames in the south, from Daventry in the west to the east
          coast. Anglian Water’s primary focus is to provide high quality drinking water and
          waste water services with a total commitment to sustainable development.


2.        Waste water treatment processes have been located on the site of Anglian Water’s
          waste water treatment works at Milton (Milton WwTW) for more than 100 years. The
          development of Cambridge has encroached towards the WwTW during that time.


3.        Milton WwTW and surrounding land on the northern edge of Cambridge has been
          identified in the Cambridge Local Plan for a residentially-led mixed use development.
          This area is known as the Cambridge Northern Fringe (East) and is a strategically
          important brownfield site capable of providing approximately 4,000 new homes.


4.        The allocation of the Milton WwTW site and its surrounding area for redevelopment
          requires the relocation of the WwTW to an alternative site. The development of this
          significant brownfield site in a highly sustainable location, close to employment,
          transport links and other services and facilities, will bring forward new community
          benefits such as affordable housing, public space and education facilities.


5.        Cambridgeshire County Council, South Cambridgeshire District Council and
          Cambridge City Council, together with land owners and stakeholders, are working to
          plan the future of the Cambridge Northern Fringe (East).


6.        Cambridgeshire County Council and Peterborough City Council (the Councils), as the
          waste planning authorities, are including the identification of a new site for the waste
          water treatment works within the Preferred Options document of their Minerals and
          Waste Local Development Framework (LDF).


7.        Anglian Water supports the Councils’ strategy to identify a location for a new waste
          water treatment works to replace Milton WwTW.




                                                           -1-                               6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

8.        Anglian Water welcomes the opportunity to engage in the consultation process
          relating to the Minerals and Waste LDF because, together with its parent company, it
          recognises:


          •          the strategic importance of this initiative to the Cambridge Sub Region; and,


          •          the opportunity to relocate to a new site that will provide operational security
                     for the long term.


9.        This Position Statement has been published by Anglian Water in advance of making
          the detailed representations during the formal six week period for consultation on the
          Preferred Options. Anglian Water has commissioned a firm of local architects to
          provide artistic impressions of three different architectural styles that could be applied
          to the construction of a new waste water treatment works within the Area of Search at
          Honey       Hill.       These       can     be     found      on     the    County       Council’s       website
          (www.cambridgeshire.gov.uk), together with other supporting documents.


10.       During the six weeks of the Councils’ statutory consultation process, Anglian Water
          will be preparing its formal submission in response to the Preferred Options
          documents. These submissions, which may be additional to or different from the
          contents of this document, will be prepared once it has had the opportunity to
          consider the Councils’ documents in full.


11.       Any comments on this document should be sent in writing to the following address.

                     Minerals and Waste Panning Manager
                     Cambridgeshire County Council
                     Box ET1011
                     Shire Hall
                     Cambridge CB3 0AP




                                                           -2-                               6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

TECHNICAL FEASIBILITY OF THE RELOCATION TO HONEY HILL

12.       Anglian Water has assessed the technical feasibility of relocating a waste water
          treatment works within the Area of Search at Honey Hill, including the necessary
          transfer and other infrastructure.


13.       A new waste water treatment works has not been fully designed because the purpose
          of the Councils’ consultation is only to identify an Area of Search. However, Anglian
          Water wishes to provide an indication of how a new waste water treatment works at
          Honey Hill could look and operate within the Area of Search at Honey Hill.


14.       A typical waste water treatment works design has been used to evaluate the technical
          feasibility of relocating Milton WwTW within the Area of Search shown in the
          Preferred Options document.                   A preliminary appraisal has been made of the
          necessary transfer and other infrastructure required to deliver the full benefits of the
          waste water treatment facilities.


15.       The general design used incorporates a comparable storm water storage, waste
          water treatment and biosolids treatment capabilities as exists at Milton WwTW but
          taking advantage of modern improvements to waste water treatment works design
          and operation.


16.       Some artistic impressions showing initial indicative views of the different appearance
          and styles that could be applied to a new waste water treatment works have been
          provided as supporting documents.                    These ideas, and other suggestions, will be
          carefully assessed and considered at the appropriate times during the planning
          process.


New Waste Water Treatment Works


17.       The Councils are not promoting a completed layout or design but have asked Anglian
          Water to provide an impression of the new waste water treatment works to assist with
          the consultation process.              In order to respond to this request, Anglian Water is
          providing visual material as an initial indication of the likely scale and form of the new
          facilities that would be required at the Honey Hill location. In doing this, Anglian
          Water has assumed that the design of a new waste water treatment works is based
          on current standard technologies for:




                                                           -3-                               6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

          •          an inlet pumping station to lift waste water from the transfer tunnel into the
                     treatment works;
          •          storm water storage;
          •          preliminary, primary and secondary waste water treatment processes;
          •          outlet pumping stations for the final effluent and storm water; and,
          •          a biosolids treatment centre.


18.       The management of odour would be a prerequisite for a waste water treatment works
          within the Area of Search at Honey Hill. It is anticipated that the preliminary treatment
          facilities would be enclosed in a building and two stage chemical scrubbers installed
          to treat all malodorous gases to the standard required. Primary tanks would also be
          covered and vented to odour control facilities as would relevant sludge processes. In
          the event that detailed analysis demonstrates that other parts of the waste water
          treatment works would need to be covered and vented to odour control, this would
          also be incorporated in the final layout design.


19.       At this initial stage it is envisaged that a preliminary treatment building would house
          the inlet pumping station, screens and grit removal plant. These processes would be
          housed in a building to assist with odour control and for the purposes of visual
          mitigation. In this building, a crane would be required to remove plant when major
          maintenance is required and there is also a need for loading bays for vehicles. The
          building would be designed to reduce the risk of odours escaping. As a result, the
          building would have a height of approximately 14 metres to the eaves.


20.       At times of heavy rainfall, storm water is received at a waste water treatment works
          and is normally stored until it is possible to treat it and return it to the watercourse.
          For this to happen at a new waste water treatment works within the Area of Search at
          Honey Hill, storm storage tanks will be required, which would be set into the ground
          and have a top height of around 1.5 metres to 2 metres above ground level.


21.       There are pressure and frictional losses at each stage of the treatment process
          resulting in an hydraulic gradient, generally controlling the height of the primary and
          secondary treatment processes, although this difference in levels can be mitigated by
          the inclusion of an inter-stage pumping station.


22.       The physical layout of the treatment process used will influence the height of the
          treatment and other related buildings on the site.                          For this exercise, we have
          assumed that primary sedimentation followed by a secondary activated sludge



                                                           -4-                               6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

          process will form the principal treatment processes.                         It is anticipated that these
          processes will be covered and vented to control odour. The primary sedimentation
          tanks would be set at a similar level to the storm tanks with the activated sludge
          process set slightly higher, at around 5m above ground level, following an inter-stage
          pumping stage.


23.       The beneficial recycling of the biosolids residue from the waste water treatment
          processes requires the liquid sludge to be thermally treated and digested in sealed
          tanks to break down the sludge and kill pathogens. These digester tanks are typically
          15 to 20 metres high and it is anticipated that they would be partially buried to limit
          their visual impact and also reduce constraints relating to the proximity of the flight
          path into Cambridge Airport.


24.       It is important to emphasise that, should the relocation of Milton WwTW progress,
          design proposals for the new waste water treatment works would be developed in
          consultation with the local planning authorities and other local stakeholders to reflect
          particular site constraints.           The design proposals may change substantially from
          those used to prepare the visual material provided as supporting documents.


Transfer Tunnel and Pipelines


25.       The relocation will require infrastructure to transfer the waste water flows from the
          existing site at Milton to the site at Honey Hill. This is likely to be a new deep level
          tunnel built between 15 and 25 metres beneath ground level.


26.       A tunnel boring machine would be used to construct the tunnel between the two sites.
          The indicative route of this tunnel and the location of an intermediate access shaft is
          shown on one of the supporting documents to this Position Statement.                                          The
          construction of the tunnel will be to current industry good practice and is unlikely to
          face risks outside of the norm for a project of this type.


27.       Once the waste water has been treated at the treatment works, the treated final
          effluent would be transferred to the River Cam in a pumping main.                                   During wet
          weather the level of incoming flow can be many times greater than the level arriving
          in dry weather.          Storm water storage tanks will be provided at the waste water
          treatment works but a further pumping main will be required to return excess storm
          flow to the River Cam. The indicative location of these mains is shown on one of the
          supporting documents to this Position Statement. It is anticipated that open trench




                                                           -5-                               6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

          construction will be used with full reinstatement of the ground to its previous
          condition.




                                                           -6-                               6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

THE AREA OF SEARCH AT HONEY HILL


28.       The Area of Search at Honey Hill provides enough space for a waste water treatment
          works, space for expansion in the future and a working area during the construction
          of the treatment works.


Geotechnical Information
29.       A review of the ground conditions within the Area of Search at Honey Hill and the
          routes of the tunnel and pumping mains has been carried out and the results show
          that the Area of Search is suitable for the construction of a waste water treatment
          works and associated infrastructure.


30.       It is anticipated that structures at this site will be founded in the Lower Chalk and
          foundations will be of standard design.                        Dewatering may be required during
          construction of the deeper tanks.                      However, excavations at the site are not
          anticipated to encounter particular difficulties.


31.       The transfer tunnel will be formed entirely in Gault Clay which is a reasonably good
          material for tunnel formation. Shaft sinking along the proposed route of the tunnel
          should not present particular difficulties. Shafts east of the River Cam will penetrate
          the Lower Chalk and Cambridge Greensand (with groundwater ingress possible at
          this latter horizon) and then Gault Clay.


32.       The pumping main excavation will encounter Lower Chalk for most of its length.
          Disturbed ground from past Coprolite mining may be encountered, but the main
          construction risk is likely to be associated with very soft peaty alluvium in the vicinity
          of the outfall structure.


33.       The Area of Search is underlain by a major aquifer but it is not in a groundwater
          protection zone.            In addition to the dewatering of excavations, construction
          techniques will minimise negative impacts on groundwater.


Archaeology
34.       A review of archaeological records for the Area of Search and the routes of the tunnel
          and pumping mains has been carried out. Previous records show that various pottery
          items have been found within the Area of Search.




                                                           -7-                               6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

35.       There are a high number of finds and some fairly significant sites relatively close to
          the proposed site. There is high potential for further archaeological interest within the
          Area of Search.


36.       Further archaeological surveys and investigations will be carried out if the project
          progresses and appropriate measures to protect and/or preserve any findings will be
          implemented.


Ecology
37.       An ecological review of the Area of Search and the routes of the tunnel and pumping
          mains have been carried out. There are no significant ecological or conservation
          issues associated with these areas.


38.       Surface works associated with the tunnel construction are limited to Milton WwTW
          and the new waste water treatment works site. Any impact on the ecology from the
          intermediate shaft would be minimal.


39.       The outfall pipeline may pass through areas of some ecological interest, but where
          impacts cannot be avoided they would be mitigated against by creation of habitat on
          site and reinstatement of any disturbed areas.


40.       Should further ecological surveys and investigations identify potentially adverse
          impacts on local ecology, appropriate mitigation will be provided.


Soils
41.       A review of the soils records for the Area of Search indicates that they are largely
          Grade 3 agricultural and so are classed as good to moderate. Although there are
          some Grade 2 soils near Horningsea, these will not be affected by the proposed
          relocation. The use of the site as a new waste water treatment works will remove the
          area from productive agricultural usage.


Landscape and visual impact

42.       A review of landscape and visual impact has been carried out for the Area of Search
          and the routes of the tunnel and pumping mains. The site is within the Green Belt
          and its generally flat terrain will afford some long distance views.


43.       It is possible to screen most of the area to be occupied by the new waste water
          treatment works from sight, but it is probable that certain equipment will be too tall to



                                                           -8-                               6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

          be effectively screened from all view points. Low Fen Drove Way is a byway over the
          A14, presently offering limited access to rural areas.


44.       The Vision for Wicken Fen has been in progress for six years. There are a number of
          public documents available that identify the larger area over which the National Trust
          has developed the Vision. The proposed Area of Search at Honey Hill is along the
          southern boundary of the Wicken Fen Vision. Additionally, the proposed Bridge of
          Reeds, if it gains funding would, according to current proposal, be located close to the
          Area of Search at Honey Hill.


45.       By including the potential for reed beds as part of the landscaping of the waste water
          treatment works, Anglian Water has tried to complement these two projects. The
          provision of different potential architectural treatments of the waste water treatment
          works also demonstrates that Anglian Water has incorporated the Vision for Wicken
          Fen and the Bridge of Reeds Project into the design process.


Noise
46.       A review of the potential noise impact of the development has been carried out. From
          this, it is considered feasible that a scheme acceptable in noise terms can be
          developed by employing appropriate mitigation as part of the overall design.


Odour control
47.       A review of the potential odour impact of the development has been carried out.
          From this, it is considered feasible that odour mitigation measures, as part of the
          overall design, along with good operational practise, can provide an acceptable
          scheme in terms of odour levels.


Access and services
48.       A review of highways access and provision of services has been carried out, showing
          that the Area of Search can be accessed from the existing bridge over the A14,
          subject to a likely need for some local highway improvements. It is also considered
          that appropriate services can be provided to the Area of Search.




                                                           -9-                               6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

Delivering the Relocation of the Waste Water Treatment Works to Honey Hill


49.       The Cambridge Local Plan assumes that the Cambridge Northern Fringe (East) will
          be redeveloped towards the end of its plan period, which is 2016. The Councils’
          Minerals and Waste LDF should be adopted in 2009.                                   Allowing time for the
          submission and determination of a planning application for a new waste water
          treatment works within the Area of Search at Honey Hill, it could be operational by
          2015. The site of Milton WwTW could also be ready for redevelopment by 2015.


50.       The timing of the redevelopment of the Cambridge Northern Fringe (East) and the
          possible receipt of planning permission for a new waste water treatment works within
          the Area of Search at Honey Hill are likely to be within the timescale for their
          respective planning framework documents.


51.       Anglian Water has assumed that the land necessary for a waste water treatment
          works within the Area of Search at Honey Hill will be acquired by negotiation or
          statutory process.




                                                           - 10 -                                       6th November 2006
Position Statement by Anglian Water
Minerals and Waste LDF Preferred Options
Relocation of Milton WwTW
Area of Search at Honey Hill
----------------------------------------------------------------------------------------------------------------------------

Economic Feasibility of Locating a Waste Water Treatment Works in the Area of Search
at Honey Hill


52.       Since the publication of the draft Preferred Options by the Councils, Anglian Water
          has undertaken a costing exercise for a waste water treatment works in the Area of
          Search at Honey Hill. This includes the transfer infrastructure from Milton WwTW to
          Honey Hill, a new waste water treatment works within the Area of Search, the
          pumping mains from Honey Hill to the River Cam for the treated water and other
          infrastructure that would be needed.


53.       This costing exercise has been based on the technical feasibility work described
          earlier in this document. The costing work has been carried out to a level appropriate
          for this early stage in the process but in such a way that Anglian Water has the
          necessary confidence in the results to allow it to give an informed judgement on the
          financial feasibility of relocating the Milton WwTW to within the Area of Search at
          Honey Hill.


54.       As Anglian Water does not have an operational need to relocate the Milton WwTW,
          the funding for any relocation will not come from its normal regulatory funding. The
          funding will have to come from the proceeds of the sale of its land at Milton, and/or
          other investment from its shareholders and funding from Government.


55.       Anglian Water believes that the relocation of the waste water treatment works to the
          Area of Search at Honey Hill is technically and economically feasible.




                                                           - 11 -                                       6th November 2006

								
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