Notice of Regulation: Testwood Water Supply Works

THE WATER SUPPLY (WATER QUALITY) REGULATIONS 2016 (AS AMENDED)

NOTICE UNDER REGULATION 28(4)

Southern Water Services Ltd: Testwood Water Supply Works

Assets affected
TH001 – Testwood WSW
TH025 Testwood Industrial WSW
Testwood Supply System

Improvement Programme Database Reference number – SRN3911

THE SECRETARY OF STATE:

  1. has on 20 October 2017 received a report from Southern Water Services Ltd(the “Company”) dated 28 September 2017 (the “Report”) which states that there is or has been a significant risk of supplying water from Testwood WSW that could constitute a potential danger to human health.
  2. GIVES NOTICE to the Company under regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 that it must satisfy the following requirement[s]:

For risks associated with:

  • Cryptosporidium
  • E. coli, Total Coliforms, Enterococci, Clostridium Perfringens
  • Loss of supply
  • Taste
  • Odour
  • Biological (animalcules)

Requirements

(a) to maintain the following measures for the duration of the Notice.

  1. Establish and maintain in place until improvement works are completed such enhanced operational measures as necessary to ensure that consumers are protected and water supplied from the site is adequately treated and wholesome.
    Date: Ongoing for the duration of the Notice.
  2. Undertake jar tests to inform coagulant dose requirements at a frequency which is commensurate with treatment changes.
    Date: Ongoing for the duration of the Notice.
  3. Carry out tests of ferric concentration on the clarifier and RGF outlets.
    Date: Ongoing for the duration of the Notice.
  4. Enhanced monitoring (3 times per week) for Cryptosporidium in the raw and treated water.
    Date: Ongoing for the duration of the Notice.
  5. Carry out weekly checks of polyelectrolyte dosing to meet the instructions for use and/or national requirements and the prescribed concentration of 0.1µg/l acrylamide.
    Date: Ongoing for the duration of the Notice.
  6. Monitoring on a weekly frequency for animalcules in the raw and treated water.
    Date: Ongoing for the duration of the Notice.

(b) to review, revise and/or make operational the following measures, by the dates specified below:

Clarification:

  1. Survey the subsidence of Accentric Clarifier and confirm the required scope of work.
    Date: Complete
  2. Assess existing clarifiers (5, 6 & 7) condition and confirm scope and programme to design and construct replacements where needed.
    Date: By 30 September 2020
  3. Construct and commission new clarifiers and filters where needed.
    Date: By 31 March 2025

Filtration:

  1. Cover Rapid Gravity Filters 13 & 14 (the Enelco filters).
    Date: Complete
  2. Replace flap valves and rubber seals on RGFs 13 & 14.
    Date: Complete
  3. Install run to waste on RGFs 13 &14.
    Date: Complete
  4. Decommission the Enelco filters (RGFs 13 & 14) and associated pipework post RGF refurbishment.
    Date: By 31 March 2025
  5. Decommission the old contact tank and build a new backwash tank.
    Date: By 31 March 2022
  6. Improve the condition of RGFs 1-12 including; valve replacement to prevent filters letting by, air blower replacement, improve the surrounding building and complete upgrade/refurbishment where needed.
    Date: By 31 March 2022
  7. Install run to waste facilities post main dose chlorination.
    Date: By 30 September 2023

Disinfection:

  1. Install balancing main pipework to enable all contact tank and treated water storage tanks to be isolated from supply.
    Date: Complete
  2. Complete the isolation, inspection and any required remediation of the South and North contact tanks, the East “Industrial” treated water tank and the West “Potable” treated water storage tank.
    Date: Complete
  3. Install a temporary ultra violet treatment unit, post contact tank.
    Date: Complete
  4. Deliver a long term solution such that the break pressure tank and pump sump no longer constitute a single point of failure at the treatment works.
    Date: By 31 January 2021
  5. Upgrade the control system to automatically stop the forward flow at the main dose chlorine with a corresponding ramp-down of the applied chlorine rate in the event of a predisinfection turbidity failure.
    Date: By 31 March 2025

Taste and odour:

  1. Undertake a study of taste and odour compounds in the raw water, including projected trends and evaluate the most appropriate carbon treatment to mitigate the risk.
    Date: Complete
  2. Install smell bells on streams 2 and 3.
    Date: By 31 March 2025

Chemical dosing and storage:

  1. Planning and installation of a new autocoagulation system for each treatment stream and removal of the existing redundant auto-coagulation unit.
    Date: By 31 March 2021
  2. Assess the ferric chloride bulk storage and day tanks and associated pumps and controls, orthophosphoric acid bund protection, and bisulphite tanks. Upgrade or replace where required.
    Date: By 31 December 2021
  3. Replace polyelectrolyte dosing system
    Date: By December 2021
  4. Replace hypochlorite dosing skid(s) to include appropriate automatic duty/ standby arrangement at pre-clarifier, post-clarifier and main dose points to prevent failure.
    Date: By December 2021
  5. Investigate and ensure chlorine monitoring is stable and representative. Move orthophosphoric acid dosing point if necessary.
    Date: By 31 December 2022
  6. Install monitoring on the pre-clarifier applied hypochlorite dosing.
    Date: By 28 February 2023
  7. Review of PAC Storage & Dosing system condition and upgrade.
    Date: By 30 April 2021
  8. Review and implement long term solution for taste and odour.
    Date: By 31 March 2025

Abstraction:

  1. Install flood protection around abstraction works.
    Date: By 28 August 2020
  2. Install raw water monitoring on Testwood Lakes (to include; Ammonia, Dissolved Oxygen, Turbidity, pH, Conductivity and Temperature)
    Date: By 30 April 2023
  3. Request discharge licence variation with Environment Agency, or complete works necessary to return wash water to head of works.
    Date: By 31 March 2025
  4. Replace or refurbish low lift pump arrangement to ensure long term resilient operation.
    Date: By 31 March 2025
  5. Deliver appropriate solution to manage silt build up within the river intakes.
    Date: By 31 March 2025

High lift pumping:

  1. Replace or refurbish high lift pump arrangement to ensure long term resilient operation.
    Date: By 31 March 2025
  2. Replace site monitoring and control systems, including shut down on the high lift pumps.
    Date: By 31 March 2025

Decommissioning:

  1. Decommission redundant assets and demolish in accordance with the Company’s policy for asset decommissioning.
    Date: By 31 March 2025

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

  1. Define a strategy for auditing the effectiveness of the measures made operational above.
    Date: To be submitted two months after the Notice is served and resubmitted as the strategy evolves.

(d) not to supply water for regulation 4(1) purposes from Testwood WSW unless the conditions specified below are satisfied

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 risk of supplying water that would constitute a potential danger to human health:

  1. Provide a progress report annually by 31 January and against the following milestones:
    • Completion of work to cover RGFs 13 and 14.
      Date: Complete
    • Completion of flap valve and rubber seal refurbishment on RGFs 13 and 14.
      Date: Complete
    • Completion of Accentric clarifier survey and scope of works.
      Date: Complete
    • Completion of run to waste scheme for RGFs 13 and 14.
      Date: Complete
    • Completion of tank inspections and associated remedial work.
      Date: Complete
    • Completion of the installation of ultra violet treatment
      Date: Complete
    • Completion of the study to determine the most appropriate carbon treatment.
      Date: Complete
    • Completion of a long term solution such that the Break Pressure Tank is no longer a single point of failure.
      Date: 28 February 2021
    • Completion of assessment and scope of works for clarifiers 5, 6 and 7.
      Date: Complete
    • Installation of auto coagulation system.
      Date: 30 April 2021
    • Completion of all other actions relating to disinfection.
      Date: Complete
    • Completion of PAC and chemical storage and dosing facilities and report on scope of resulting works.
      Date: 31 May 2021
    • Completion of all remedial works completed on RGFs 1-12.
      Date: 30 April 2022
    • Completion of all other action relating to filtration.
      Date: 30 November 2023
    • Completion of long-term construction items.
      Date: 30 April 2025
    • Completion of all other actions relating to high lift pumping.
      Date: 31 May 2025
    • Completion of all other actions relating to abstraction.
      Date: 31 May 2025
    • Completion of all other actions relating to chemical dosing and storage
      Date: 31 May 2025
    • Completion of all other actions relating to taste and odour.
      Date: 31 May 2025
  2. Review the risk assessment for Testwood WSW as required by Regulation 27(3) and subsequently submit a revised regulation 28 report accompanied by a signed board level declaration.
    Date: As required and within 2 months of completion of all measures.
  3. Submit a satisfactory completion report.
    Date: 31 May 2026

Failure by the Company to comply with this Notice may result in enforcement proceedings under section 18 of the Act.


Signed by authority of the Secretary of State,
Milo Purcell
Deputy Chief Inspector
22 January 2021
DWI Ref: SRN 3911
Version 6

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