Odour Improvement Project Mogden Sewage Treatment Works Residents - - PDF document

Odour Improvement Project

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Mogden Sewage Treatment Works

Residents’ Liaison Meeting 26 September 2007

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Odour Improvement Project

• Scope of work:

– Cover key parts of the treatment process, including:

• Inlet works (East and West side of Mogden)
• Primary settlement tanks (East side)
• Two storm tanks (East Side)

– Independent tests have been used to decide what areas of the site to cover – Install equipment to extract and treat the odorous air from the covered areas:

• Two new odour control units (East and West side)
• Designed to robustly comply with the requirements
• f the odour abatement notice.

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Agenda

17:15 Site walk-around 18:15

1.

Apologies

2.

Odour Improvement Project

3.

Odour

4.

Mosquitoes

5.

Working for a cleaner Thames

6.

Further points raised by residents

7.

Communications

8.

Any other business and date of next meeting 20:15 Meeting Close

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Progress of Works

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East Works Progress

AREA PROGRESS Inlet Penstocks 100% Screenhouse & Screens 90% Screenings Handling Plant 95% Grit Channels 70% Storm Weir 95% Grit Handling Plant 80% Storm Tanks 4 and 5 95% Circular PSTs (Decommission) 0% Rectangular SSTs 65% Odour Control Unit (Chemical) 100%

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Screenings Handling Plant

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CV Grit Channels 1 and 2

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Storm Weir

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Grit Handling Plant

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Storm Tank 5

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Secondary Settlement Tanks 2 & 3

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Secondary Settlement Tank 4

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Secondary Settlement Tank 1

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East Odour Control Unit

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West Works Progress

AREA PROGRESS Chambers Upstream of Screens 100% Fine Screens 70% Cross Flow Grit Traps 95% Washpactors and Skip Loaders 100% Grit Handling Plant 70% Screw Pumps 100% Pre-Aeration Lanes 100% Odour Control Unit (Biological) 90%

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Cross Flow Grit Traps

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Pre-Aeration Lanes

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Noise Update

Noise attenuator installed

• n 17 May 2007 (pictured)

Significant noise reduction

• n site

Final noise survey to be

undertaken tonight (26/09/07), commencing at 9:00pm

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Operation of Mogden- Update

Informative email notifications sent to residents: 17 Proactive Notifications: Odour Improvement project works (x12) Site Maintenance works (x5) 2 Reactive Notifications: Interruption to Power Supply Channel Cleaning

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Complaints Received at Mogden

10 20 30 40 50 60 70 80 90 100 Apr-05 May-05 Jun-05 Jul-05 Aug-05 Sep-05 Oct-05 Nov-05 Dec-05 Jan-06 Feb-06 Mar-06 Apr-06 May-06 Jun-06 Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 Jan-07 Feb-07 Mar-07 Apr-07 May-07 Jun-07 Jul-07 Aug-07

Mosquitoes Odour and mosquitoes Odour

N.B Figures reported to 31 August 07

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Mosquitoes

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Surveying and controlling Mosquitoes at Mogden

Strict year-round programme to survey and control mosquitoes Summer surveying and treatment programme began in mid-April 07: Weekly Surveys Target Summer breeding sites Mosquito treatment: Less than two days after the weekly survey Controls regular breeding sites & ad hoc sites as identified in the

surveys

Spraying near standing water

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Methods of Mosquito control at Mogden

Physical Site housekeeping- Removing Mosquito breeding sites Biological Spraying Mosquito larvae with bacteria Mechanical Using ultraviolet insect traps Chemical Controlling adult Mosquitoes with pesticides

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Number of sites inspected for Mosquitoes at Mogden

50 100 150 200 250 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

Week

2003 2004 2005 2006 2007

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Percentage of sites surveyed found to contain Mosquito activity

10 20 30 40 50 60 70 80 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 Week % 2003 2004 2005 2006 2007

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Number of sites where larvae have been found

5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 Week 2003 2004 2005 2006 2007

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2 4 6 8 10 12 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 Week 2003 2004 2005 2006 2007

Number of sites where Adult Mosquitoes have been found

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Mosquito Project 2007

Project Scope: Target the main over-wintering sites: Digester galleries, aeration galleries, main pumping station drywell, power

house basement & pumping stations 4 & 5

Project aim: To physically alter sites to reduce the number of places where

Mosquitoes can breed and to make control work easier

Project commenced in March 2007

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Working for a Cleaner Thames

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Working for a cleaner Thames- Update

Proposed site improvement works: Increase the amount of flow that can be fully treated Less use of storm tanks Includes new covered inlet works, covered primary tanks and

new aeration lanes

Odour control of the new works Reduce the likelihood of overflows from the works to the River

Thames

To help boost oxygen levels in the tidal Thames Improving the water quality and the habitants for aquatic life

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Preferred Solution for Mogden

Area of development. Other land in applicants ownership. Buildings. Site roads / hardstanding. Above ground structures. New & re-profiled embankment. Soft landscaped areas. Earth retaining wall.

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Working for a cleaner Thames- Update

Timescales: Planning Application: TBC- Delay due to finalisation of details Proposed construction date: Spring/Summer 2008 Complete and operational: Spring/Summer 2012 Public displays were held in Isleworth Public Library on the 21st,

22nd and 24th of May 2007:

Well received by local residents and businesses Questions answered by Thames Water representatives Comments Book completed

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Further points raised by residents

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Communication

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Communication

E-mail notifications:

Informing residents of possible increase in odour

Mogden newsletter:

Updating residents with progress on the odour improvement project To be distributed by end September/Beginning October 2007

Mosquito Campaign:

‘Help control mosquitoes in your area’

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Communication

Contact us about Mogden: Via the customer centre: 0845 9200 800 Through our website:

www.thameswater.co.uk/mogden

By post: Thames Water, PO Box 436, Swindon,

SN38 1TU

Visit our website: Categorised ‘Answers to your questions’ webpage Mogden weekly site log webpage (includes regular

updates of the Odour Improvement project)

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Thank You