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South East Water Limited – Windmill Hill Treatment Works Disinfection Risks

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

Reference: SEW-2024-00001

Version Number: 1

Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): South East Water Limited, with registered number 02679874 (hereinafter called ‘the Company’).

Assets Affected:

  • T229 – Windmill Hill Treatment Works

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 1 September 2023, which states that there is or has been a significant risk of supplying water from Windmill Hill 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

Inadequately disinfected water

Escherichia coli (E. coli)

T229-TREATMENT-C002

Inadequately disinfected water

Coliform bacteria

T229-TREATMENT-C001

Inadequately disinfected water

Enterococci

T229-TREATMENT-C003

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. Optimisation of all existing treatment processes.
    Date: Ongoing for the duration of this Notice
  2. Operation of all processes within defined normal operating ranges with appropriate triggers, responses and contingency procedures.
    Date: Ongoing for the duration of this Notice
  3. Online turbidity and chlorine monitoring with appropriate alarms and failsafe shutdown.
    Date: Ongoing for the duration of this Notice
  4. Enhanced and large volume operational monitoring for microbiological parameters at Windmill Hill Treatment Works.
    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. Complete optioneering review to confirm a programme of work to provide adequate disinfection under all circumstances and flow rates.
    Date: 30 September 2024
  2. Complete the detailed design of the preferred solution identified in measure (b)1 above.
    Date: 31 March 2025
  3. Complete the construction, installation and commissioning of the chosen disinfection system as defined by measures (b)1 and (b)2. Commissioning must include the following to account for the changes made:
  4. An appropriate maintenance regime for any installed processes;
  5. Full integration of the new processes into the site control and monitoring systems;
  6. Updating of the Site-Specific Disinfection Policy and any associated site-specific procedures;
  7. Updating of the Site Operating Manual and removal of all out-of-date material from circulation; and
  8. Provisions of adequate training for all relevant personnel on the operation, repair and maintenance of the installed process and the revised procedures, policies and manual.
    Date: 31 March 2027

(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 August 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 Windmill Hill 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. Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
    .
    Date: 30 September 2024
  3. Report on the output of the optioneering review as detailed in measure (b)1.

Date: 31 October 2024

  1. Report on the detailed design of the preferred solution a detailed in measure (b)2.

Date: 30 April 2025

  1. Confirm the completion of installation and commissioning of the chosen disinfection system along with an updated SSDP, SOP and evidence of training for all relevant operators as detailed in measure (b)3.

Date: 30 April 2027

  1. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
  2. 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
  3. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 30 April 2028

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
26 June 2024
Reference: SEW-2024-00001

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