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Thames Water Utilities Limited – AMP8 Coppermills Works Cryptosporidium

Notice under regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 (as amended)

Reference: TMS-2023-00008

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Thames Water Utilities Limited, with registered number 02366661 (hereinafter called ‘the Company’).

Assets Affected:

  • Works and supply systems listed in annex A.

Details of this Notice:

  1. The Drinking Water Inspectorate (‘the Inspectorate’) has received a regulation 28(1) report of the Water Supply (Water Quality) Regulations 2016 (as amended) (‘the Regulations’) from the Company dated 16 March 2023, which states that there is or has been a significant risk of supplying water from Coppermills works (and associated assets as applicable) that could constitute a potential danger to human health or could be unwholesome.
  2. Consequently, this Notice is served on the Company by the Inspectorate on behalf of the Secretary of State, under regulation 28(4) for the assets listed above, for risks associated with:

Description of Risk

Hazard/ Hazardous Event/ Parameter

Hazard I D

Microbiological contamination

Cryptosporidium

TMS-4-T02S.001-MDCT007-T02S.001-C111A

Regulation 26 disinfection

Turbidity

TMS-4-T02S.001-MDCT142-T02S.001-A002

Table 1: Table of the hazards, hazardous events, and/or parameters covered by this Notice, including the Hazard I D numbers and the description of risks.

  1. The Company are required to satisfy the following requirements.

The date given is that until or by which the requirements must be maintained or satisfied, as appropriate.

Requirements:

(a) To maintain the following measures for the period specified in each case:

  1. Continuous sampling for Cryptosporidium at a suitable sampling point, downstream of the slow sand filtration treatment stage at Coppermills works.
    Date: Ongoing for the duration of this Notice.
  2. An appropriate operational sampling regime for Cryptosporidium, turbidity, microbiological faecal indicators, and other relevant parameters, within the raw water source(s) and within the water treatment works at other sampling points within the process and in the final treated water.
    Date: Ongoing for the duration of this Notice.
  3. Operation of all processes within defined operating ranges with appropriate triggers, responses, and contingency procedures.
    Date: Ongoing for the duration of this Notice.
  4. Ensure the works control and shutdown system is operational and that monitors are calibrated and maintained at their predefined frequencies.
    Date: Ongoing for the duration of this Notice.
  5. Continuously review all water quality critical control points and mitigation measures, with a view to updating this Notice with additional measures where required. Ensure that any new risk identified is assessed in accordance with the Company’s Drinking Water Safety Plan (DWSP) methodology.
    Date: Ongoing for the duration of this Notice.
  6. Continue to implement company water quality response procedures for investigation of contraventions including process optimisation and reporting; consumer complaints procedures; event response procedures for event actions; and notification criteria.
    Date: Ongoing for the duration of this Notice.
  7. Continue to implement the company’s Site Operating Manual (SOM), defining normal operating ranges, triggers, response, and contingency procedures, with controlled updates and review programmes. Implement the company’s Internal Waiver Process, where a deviation from the SOM is identified.
    Date: Ongoing for the duration of this Notice.
  8. Ensure that the Site-Specific Disinfection Policy for Coppermills works remains up-to-date and implemented.
    Date: Ongoing for the duration of this Notice.
  9. Maintain contingency plans to protect human health in the event of a risk associated with drinking water quality, which should include liaison with local authorities and Public Health England to agree any actions needed to protect human health and issuing of advice to consumers, where required.
    Date: Ongoing for the duration of this Notice.
  10. In accordance with the requirements of Regulation 27(3), continuously review and revise as necessary the regulation 27 risk assessment reports for Coppermills works and associated supply systems and submit revised regulation 28 reports to the Inspectorate as necessary, in accordance with the Regulations.
    Date: Ongoing for the duration of this Notice.
  11. Continue to implement the company’s operating standard for slow sand filters, including monthly rapid gravity filter media depth inspections.
    Date: Ongoing for the duration of this Notice.
  12. Trained and competent operational personnel to follow the Company’s procedure when returning slow sand filters back into supply.
    Date: Ongoing for the duration of this Notice.
  13. Continue to operate existing slow sand filters optimally, by maintaining the following measures:
    • Carry out and record daily inspections of slow sand filters for animal ingress.
    • Promptly report any animal ingress into any exposed (open-air) treatment stages, including slow sand filters, to appropriate competent Water Quality staff in accordance with the Company’s procedure.
    • Carry out appropriate analysis and disposal of any animal carcasses in accordance with the Company’s procedure.
    • Regular monitoring of slow sand filter beds’ flow rate changes and associated alarms to ensure flow rates are properly managed to prevent particle detachment within the beds.
    • Appropriate slow sand filter flow control using the outlet valve to ensure the rate of change does not exceed predetermined limits.
      Date: Ongoing for the duration of this Notice.

(b) To review, revise or make operational the following measures, by the dates specified in each case:

  1. Confirm the programme for delivery for the identified improvement works for Coppermills works.
    31 December 2024.
  2. Develop and deliver catchment management activities, working with landowners and land managers, to reduce the risk of Cryptosporidium oocysts entering the raw water supply to Coppermills works.
    Date: 31 March 2026.
  3. Design, procure, install, and operate a system linking sewage treatment works and combined storm overflow alarms with time of travel river models and abstraction systems to minimise the risk of Cryptosporidium oocysts being abstracted into the raw water storage reservoirs.
    Date: 31 March 2026.
  4. Establish enhanced catchment monitoring for Cryptosporidium oocysts at points upstream of raw water abstraction points and improve laboratory analysis times so that the laboratory data can be used with time of travel models, as specified in measure b(3), to manage abstraction systems in real time, so that the abstraction of Cryptosporidium oocysts into the raw water storage reservoirs is minimised.
    Date: 31 March 2026.
  5. Complete Computational Fluid Dynamics (CFD) studies of all outstanding raw water storage reservoirs, to understand and actively manage retention times and minimise the risk of Cryptosporidium oocysts entering Coppermills works.
    Date: 31 March 2027.
  6. Complete an investigation at Coppermills works, to confirm the chosen technical solution for addressing the risk of Cryptosporidium at Coppermills works.
    Date: 31 August 2025.
  7. Complete the planning, procurement strategy and design for the improvement works identified within measure b(6).
    Date: 31 March 2027.
  8. Complete the construction, installation and commissioning of the technical solution identified in measure b(6). Commissioning shall include the following:
    • An appropriate maintenance regime for any installed process.
    • Full integration of the new (or modified) processes into the site control and monitoring systems.
    • Updating the Site-Specific Disinfection Policy and any associated site-specific procedures.
    • Updating of the Site Operating Manual and removal of all out-of-date material from circulation.
    • Provisions of adequate training for all relevant personnel on the operation, repair, and maintenance of the installed (or modified) process and revised procedures, policies, and manual.

Date: 31 March 2030.

(c) To audit whether the measures have been effective by the following means:

  1. Define an audit strategy to monitor the effectiveness of the measures specified in sections (a) and (b).
    Date: 31 July 2024.
  2. Implement, and keep under continuous review, the audit strategy defined in measure (c)1.
    Date: Following completion of measure (c)1. onwards.

(d) Not to supply water for regulation 4(1) purposes from Coppermills works and its associated supply systems, or not to so supply unless the specified conditions below are satisfied:

  1. Not Applicable.

(e) To provide the following information in the time and manner specified below to enable monitoring of progress towards the mitigation of the risks:

  1. Provide a progress report annually.
    Date: by 31 January each year.
  2. Confirm to the Inspectorate the programme for delivery for the identified improvement works for Coppermills works as specified in measure b(1).
    Date: 31 January 2025.
  3. Provide a report confirming the completion of: the delivery of catchment management activities, as specified in measure b(2); the installation and operation of a system linking the sewage treatment works and combined storm overflow alarms, as specified in measure b(3); and the establishment of enhanced catchment monitoring, as specified in measure b(4).
    Date: 30 April 2026.
  4. Provide a report confirming the completion of CFD studies, and the implementation of the findings of the study, as specified in measure b(5).
    Date: 30 April 2027.
  5. Provide a report to confirm the high-level design of the technical solution, as specified in measure b(6). The report shall include the steps to be taken, timetable, programme of works, completion date and location, for the delivery of the technical solution at Coppermills works.
    Date: 30 September 2025.
  6. Provide the detailed design and procurement strategy of the technical solution and improvement works as identified in measure b(7).
    Date: 30 April 2027.
  7. Provide a report to confirm and evidence the completion of construction, installation and commissioning, as specified in measure b(8).
    Date: 30 April 2030
  8. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: 31 August 2024.
  9. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision.
  10. Submit a report in the event that any completed measures of this Notice need to be altered in any way, for any reason.
    Date: Ongoing for the duration of this Notice.
  11. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 30 April 2031

Further Details of this Notice:

  1. Any product or substance used as a result of the requirements in this Notice must comply with regulation 31.
  2. Under regulation 28(6) the Inspectorate, on behalf of the Secretary of State, may by notice served on the Company, revoke or vary this Notice.
  3. Failure by the Company to comply with this Notice may result in enforcement proceedings under section 18 of the Water Industry Act 1991 (as amended).

Signed
Nicholas Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
20 May 2024
Reference: TMS-2023-00008

Annex A

Asset or Supply System Name

Reference

Coppermills works

T02S.001

Barrow Hill

YTMS1172 

Bromley Common, Bromley Inset (LNW) (TW Supply system: Farnborough)

YTMS3000 

Chessington

YTMS1177 

Chigwell

YTMS1178 

Coronation Square Inset (IWNL) (TW Supply System Woodford) 

YTMS3026 

Crouch Hill

YTMS1186 

Crystal Palace

YTMS1187 

Farnborough

YTMS1192 

Finsbury Park

YTMS1194 

Hale Village Inset (LNW) (TW Supply system Woodford)

YTMS3009

Hampton 30/36

YTMS1197 

Hampton 42 

YTMS1198 

Heart of East Greenwich Inset (LNW) (TW Supply system Hampton 30/36)

YTMS3005

High Beech

YTMS1201 

Hoddesdon

YTMS1202

Maiden Lane

YTMS1207 

Marine Wharf, Deptford Inset (LNW) (TW Supply system Surbiton 30 inch)

YTMS3002 

Merton Export (Sutton & East Surrey) (TW Supply system Surbiton 30 inch) 

YTMS2011

Mill Hill

YTMS1209 

Millharbour Inset (LNW) (TW Supply system Finsbury Park)

YTMS3017 

New South Quarter, Croydon Inset (LNW) (TW Supply system: Russell Hill) 

YTMS3001

Nine Elms Park Inset (IWNL) (TW Supply system Hampton 30/36)

YTMS3024 

Nine Elms WSZ (Battersea) Inset (LNW) (TW supply system Hampton 30/36) 

YTMS3003

Norwood

YTMS1213 

Nunhead

YTMS1214 

Poplar Riverside (IWNL) (TW Supply system: Finsbury Park)

YTMS3025 

Putney

YTMS1216 

Russell Hill

YTMS1218 

Sewardstone

YTMS1219 

Shootup Hill

YTMS1220 

Surbiton 30-inch

YTMS1224 

TWRM (IWNL) (TW supply system: multiple)

YTMS3022 

Woodford

YTMS1234 

Table 2: List of Assets Affected by this Notice.
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