Southern Water Services Limited – Sandown Water Supply Works
Notice under regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 (as amended)
Reference: SRN-2018-00020
Version Number: 6
Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Southern Water Services Limited, with registered number 02366670 (hereinafter called ‘the Company’).
Assets Affected:
- TI016 Sandown Brading WSW
- TI017 Sandown Shanklin WSW
- Y004 Isle of Wight
Details of this Notice:
- 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 8 July 2019, which states that there is or has been a significant risk of supplying water from Sandown Shanklin Water Supply Works (and associated assets as applicable) that could constitute a potential danger to human health or could be unwholesome.
- 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 |
|---|---|---|
Ingress route and failure of treatment process | Clostridium perfringens | 68704, 68639 |
Ingress route and failure of treatment process | E. coli | 68707, 68642 |
Ingress route and failure of treatment process | Enterococci | 68708, 68643 |
Ingress route and failure of treatment process | Total Coliforms | 68706, 68641 |
Breakthrough presenting risk to public health | Cryptosporidium |
68703, 68638 |
Failure of treatment poses risk to wholesomeness | Lead | 68739, 68674 |
Failure of treatment poses risk to wholesomeness | Manganese | 68746, 68681 |
Insufficient water supply to downstream consumers | No Supply | 68762, 68763, 68697, 68698, 68699 |
Failure of treatment poses risk to wholesomeness | Pesticides | 68718, 68653 |
Failure of treatment poses risk to wholesomeness | pH | 68758, 68693 |
- 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:
- 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 this Notice - Enhanced monitoring (3 times per week) for Cryptosporidium on the raw and continuous on the treated water of both the Brading and Shanklin reservoir lines until validated UV is operational.
Date: Ongoing for the duration of this Notice - Daily enhanced monitoring for E.coli, coliforms, Clostridium and Enterococci microbiology from both the Brading and Shanklin final water sample points until validated UV is operational.
Date: Ongoing for the duration of this Notice - Enhanced monitoring of disinfection by-product generation at both the treated sample point and all downstream treated water reservoirs until 12 months after UV installation.
Date: Ongoing for the duration of this Notice - Continuous monitoring of the XTN RGF stream (also known as Extended Stream) in order to review and optimise performance and backwash regime.
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:
- Install and commission UV units on both the Brading and Shanklin lines.
Date: Complete - Document and implement control procedures to manually enhance RGF drain down prior to washing.
Date: Complete - Complete investigations into root cause of poor RGF drain down and implement corrective measures as required.
Date: Complete - Investigate the performance of the RGFs and the design and performance of the lamella clarifiers and identify any corrective measures.
Date: Complete - Investigate options to improve manganese removal.
Date: Complete - Replace PACl storage tanks.
Date: Complete - Replace all required valves on the GAC and introduce automated backwash cycle.
Date: Complete - Produce full Clear Water Tank replacement plans and design.
Date: Complete - Replace the wooden stop logs from the Contact Tank outlet weirs.
Date: Complete - Install orthophosphoric acid dosing.
Date: Complete - Confirm measures for manganese removal to be implemented
Date: Complete - Confirm measures for RGF and lamella performance to be implemented
Date: Complete - Implement and commission measures to improve manganese removal, as identified in step (b)11.
Date: Complete - Implement and commission corrective measures for RGF and Lamella clarifiers as identified in step (b)12.
Date: Complete - Replace Clear Water Tank and High Lift Pumps.
Date: 31 March 2025 - Commission Clear Water Tank and High Lift Pumps
Date: 30 September 2025 - Improve wash water lagoon discharge capability.
Date: 31 March 2025 - Replace MCC 2.
Date: 31 March 2025 - Review current flood risk and implement remedial works to ensure suitable resilience.
Date: 31 March 2025 - Carry out power resilience assessment (ECM4007) and implement recommended actions.
Date: 31 March 2025 - Commission measures with completion date of 31 March 2025. (b) 17, 18, 19, 20.
Date: 31 March 2026 - Produce a short term operational contingency plan for mitigating risks associated with low raw water pH.
Date: Complete - Complete the outline design for the long-term solution for mitigating risks associated with low raw water pH.
Date: Complete - Install the long-term solution for mitigating risks associated with low raw water pH.
Date: 31 October 2024 - Commission the long-term solution for mitigating risks associated with low raw water pH.
Date: 28 February 2025
(c) To audit whether the measures have been effective by the following means:
- Define an audit strategy to monitor the effectiveness of the measures specified in sections (a) and (b).
Date: Complete - 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 Sandown Shanklin WSW or Sandown Brading WSW, or not to so supply unless the specified conditions 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 risks:
- Provide a progress report annually.
Date: by 31 January each year. - Report confirming installation of UV units.
Date: Complete - Identification of corrective actions for RGF drain down and confirmation of manual procedures to enhance RGF drain down.
Date: Complete - Completion of investigation into performance of RGFs and lamella clarifiers and outline of recommended actions.
Date: Complete - Outcome of investigation on manganese removal.
Date: Complete - Replacement of valves on GAC, introduction of automated backwash cycle and PACl storage tank replacement.
Date: Complete - Clear Water Tank replacement plans and design.
Date: Complete - Report confirming Installation of orthophosphoric acid dosing.
Date: Complete - Implementation of measures to improve manganese removal, as confirmed in step (b)11.
Date: Complete - Implementation of corrective measures for RGF and lamella performance as confirmed in step (b)12.
Date: Complete - Report confirming replacement of Clear Water Tank and High Lift Pumps.
Date: 30 April 2025 - Report confirming commissioning of Clear Water Tank and High Lift Pumps.
Date: 31 October 2025 - Completion of actions (b) 17, 18, 19, 20 due by 31 March 2025.
Date: 30 April 2025 - Commissioning of actions (b) 17, 18, 19, 20 due by 31 March 2025.
Date: 30 April 2026 - Provide a short term operational contingency plan for mitigating risks associated with low raw water pH.
Date: Complete - Provide the outline design for the long-term solution for mitigating risks associated with low raw water pH.
Date: Complete - Provide a report evidencing the installation of the long-term solution for mitigating risks associated with low raw water pH.
Date: 30 November 2024 - Provide a report evidencing the commissioning of the long-term solution for mitigating risks associated with low raw water pH.
Date: 31 March 2025 - Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
Date: Complete - Submit any revisions of the audit strategy produced under measure (c)2.
Date: Within 1 month of a revision - 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 - Submit a satisfactory completion report accompanied by a revised regulation 28(1) report with Board level Director sign-off.
Date: 30 April 2027
Further Details of this Notice:
- Any product or substance used as a result of the requirements in this Notice must comply with regulation 31.
- 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.
- 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
30 July 2024
Reference: SRN-2018-00020 V6