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Thames Water Utilities Limited – Baunton Water Treatment Works, Cryptosporidium and Turbidity Risk

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

Reference: TMS-2022-00004

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:

Asset Name

Reference

Baunton Water Treatment Works

T07U.720

Cirencester Community Supply System

YTMS1181

North Cotswolds Community Supply System

YTMS1212

Rissington Inset (Albion) (TW Community: North Cotswolds) Supply System

YTMS3011

Table 1: List of assets affected and associated reference numbers

Details of this Notice:

  1. The Drinking Water Inspectorate (‘the Inspectorate’) has received regulation 28(1) reports of the Water Supply (Water Quality) Regulations 2016 (as amended) (‘the Regulations’) from the Company dated 18 June 2021 and 16 June 2022, which state that there is or has been a significant risk of supplying water from Baunton Water Treatment 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

Turbidity. Failure to subject water to sufficient preliminary treatment to prepare it for disinfection (regulation 26(1)(b) and 26(6)(b)). Failure to verify the effectiveness of the disinfection process (regulation 26(2)(b)).

Turbidity

TMS-4-T07U.720-MDCT142-T07U.720-A002

Cryptosporidium

Cryptosporidium

TMS-4-T07U.720-MDCT007-T07U.720-C111A

Table 2: 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. Operation of all processes within defined operating ranges, with appropriate triggers, responses and contingency procedures.
    Date: Ongoing for the duration of this Notice
  2. Online turbidity monitoring of water prior to disinfection, with appropriate alarms and failsafe shutdowns where applicable.
    Date: Ongoing for the duration of this Notice
  3. Ensure the water treatment works’ control and shutdown systems are operational and that monitors are calibrated at predefined frequencies.
    Date: Ongoing for the duration of this Notice
  4. Continuous monitoring of raw and treated water with control systems, alarmed operating limits and automatic shutdowns as appropriate.
    Date: Ongoing for the duration of this Notice
  5. Ensure that turbidity monitoring equipment is maintained in accordance with manufacturers’ instructions.
    Date: Ongoing for the duration of this Notice
  6. Maintain up-to-date Site Operating Manual (SOM), defining normal operating ranges, triggers, response and contingency procedures, with controlled update and review programmes. Internal waiver process is followed where deviation from SOM is required.
    Date: Ongoing for the duration of this Notice
  7. Up-to-date and subject to continuous review, site specific disinfection policy, which identifies clearly and unequivocally how disinfection is achieved and maintained at the works.
    Date: Ongoing for the duration of this Notice
  8. Maintain contingency plans (including liaison with relevant stakeholders, as appropriate) to protect human health.
    Date: Ongoing for the duration of this Notice
  9. Take all reasonable operational steps (and continue to enhance the effectiveness) to ensure that water that is not compliant with the requirements of regulations 4 and 26 is prevented from entering supply.
    Date: Ongoing for the duration of this Notice
  10. Enhanced operational monitoring for microbiological faecal indicators.
    Date: Ongoing for the duration of this Notice
  11. Continuously monitor raw water for Cryptosporidium at Baunton Water Treatment Works following the completion of measure (b)1.
    Date: Following completion of measure (b)1, and thereafter for the duration of this Notice

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

Cryptosporidium risk

  1. Install continuous raw water Cryptosporidium monitoring at Baunton Water Treatment Works.
    Date: Prior to the return to supply of Baunton Water Treatment Works for regulation (4)1 purposes.
  2. Review the risk from Cryptosporidium, including a review between the Company’s catchment risk assessments, hydrogeological pathways and water quality monitoring data, against the realised capabilities of the existing disinfection process in place, and compliance with the recommendations of the Expert Group on Cryptosporidium ‘Badenoch and Bouchier’.
    Date: 31 December 2022

Turbidity risk

  1. Investigate and implement measures to ensure turbidity is less than 1 NTU prior to disinfection at Baunton Water Treatment Works.
    Date: Complete
  2. Conduct a critical review of compliance with regulation 26(1)(b) and 26(6)(b) at Baunton Water Treatment Works to ensure water leaving the treatment works has received sufficient preliminary treatment to prepare it for disinfection.
    Date: 31 May 2023

Solution

  1. Design a disinfection and treatment process (or modify the existing process) to address any unmitigated risks from Cryptosporidium and turbidity. This must also consider monitoring to verify the effectiveness of the designed solution.
    Date: Complete
  2. Complete the construction, installation (or modify the existing) and commissioning of the chosen disinfection and treatment process, designed under measure (b)5. Commissioning must include the following to account for the changes made:
  • A gap analysis between the risks identified, under the reviews completed in measures (b)2 and (b)4, and the treatment capabilities of the installed solution;
  • An appropriate maintenance regime for any installed process;
  • Full integration of the new (or modified) processes into the site control and monitoring systems;
  • Updating of 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; and
  • Provisions of adequate training for all relevant personnel on the operation, repair and maintenance of the installed (or modified) process and the revised procedures, policies and manual.
    Date: 31 October 2023

(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 December 2022
  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 Baunton Water Treatment Works, 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 the installation and commissioning of continuous Cryptosporidium monitoring (measure (b)1).
    Date: 1 month following the completion of measure (b)1
  3. Report the outcomes of the review required under measure (b)2.
    Date: 31 January 2023
  4. Report the findings of the investigation completed under (b)3 and resulting measures implemented.
    Date: Complete
  5. Report the outcome of the review required under measure (b)4.
    Date: 30 June 2023
  6. Submit a report outlining the disinfection and treatment process design specification, as necessitated by measure (b)5.
    Date: Complete
  7. Evidenced completion of measure (b)6.
    Date: 30 November 2023
  8. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    Date: 31 January 2023
  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 November 2024

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
18 November 2022
Reference: TMS-2022-00004 V1

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