South East Water Limited – Boxley Treatment Works_Disinfection Risks

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

Reference: SEW-2023-00006

Version Number: 2

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:

  • T371 – Boxley 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 21 September 2021, which states that there is or has been a significant risk of supplying water from Boxley 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)

T371-TREATMENT-C002

Inadequately disinfected water

Coliform bacteria

T371-TREATMENT-C001

Inadequately disinfected water

Enterococci

T3371-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 Boxley 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. Review options to allow shutdown on final water turbidity and chlorine levels.
    Date: Complete
  2. Plan and design the option to allow shutdown on final water turbidity and chlorine levels.
    Date: 31 January 2025
  3. Install and commission the chosen solution to allow shutdown on final water turbidity and chlorine levels.
    Date: 30 September 2026

(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: Complete
  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 Boxley 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. Provide a copy of the audit strategy.
    Date: Complete
  3. Report on the review of options to allow shutdown on final water turbidity and chlorine levels and provide dates for the planning, design, installation and commissioning.
    Date: Complete
  4. Confirm the completion of installation and commissioning of the shutdown processes.
    Date: 31 October 2026
  5. Submit any revisions of the audit strategy produced under measure (c)2.
    Date: Within 1 month of a revision
  6. 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
  7. Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
    Date: 30 November 2027

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
17 June 2024
Reference: SEW-2023-00006

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