Yorkshire Water Services Limited – Ingbirchworth WTW Manganese and Raw Water Monitoring
Notice under regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 (as amended)
Reference: YKS-2022-00006
Version Number: 1
Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): Yorkshire Water Services Limited, with registered number 02366682 (hereinafter called ‘the Company’).
Assets Affected:
- Ingbirchworth 2 WTW Works Inlet (A3612850);
- Ingbirchworth 2 WTW Works In Royd Moor (A3614600);
- Ingbirchworth No.2 WTW (T3692910);
- Ingbirchworth Water Supply System (YSAI00130873).
Details of this Notice:
- The Drinking Water Inspectorate (‘the Inspectorate’) has received a set of regulation 28(1) reports of the Water Supply (Water Quality) Regulations 2016 (as amended) (‘the Regulations’) from the Company dated between 23 September 2021 and 10 December 2021, which states that there is or has been a significant risk of supplying water from Ingbirchworth water treatment 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 |
|---|---|---|
|
Water Quality issues due to manganese within raw water. |
Manganese |
10472 |
|
Failure of treatment process to control manganese levels entering supply due to issues related to turnover in raw water reservoirs. |
Manganese |
14469 |
|
Failure of treatment process to achieve final water turbidity within acceptable limits due to issues related to turnover in raw water reservoirs. |
Turbidity |
17334; 20881. |
- 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:
- Optimisation of current treatment processes within the operational limits that have an impact on manganese removal and other discolouration parameters.
Date: Ongoing for the duration of this Notice - Maintain raw water monitoring for manganese (total and soluble) and ammonia at Ingbirchworth impounding reservoir (IRE).
Date: Ongoing for the duration of this Notice - Continue to review opportunities for catchment management activities with stakeholders and implement protective measures, where feasible, to improve raw water quality.
Date: Ongoing for the duration of this Notice - Respond to any PCV failure or consumer contact, relating to discolouration parameters (such as manganese), in line with company procedures.
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:
- Develop a mitigation plan for responding to changes in raw water quality (consideration should be given for: manganese (M n O 2 and M n 2 +), dissolved oxygen, iron (F e 2 + and F e 3 +), temperature, ammonia, ammonium, phosphorus) for Ingbirchworth IRE, to ensure appropriate triggers are in place to enhance monitoring and shorten analytical turnaround time for samples for improved response and escalation, with consideration for any additional treatment onsite that may be required. To include:
- Process optimisation steps to mitigate against the risk of elevated concentrations of manganese and elevated turbidity;
- Appropriate escalation in response to onsite checks for all of the parameters listed.
Date: 31 December 2022
- Develop a procedure for appropriate escalation between all of the raw water teams, catchment teams, water quality scientists, and site production teams in the Ingbirchworth supply system. This should be in addition to regular communications between these teams. Appropriate escalation procedures should be defined for visual changes in raw water quality at Ingbirchworth IRE; sample results that are outside normal operating levels; and site production observations on raw water changes (e.g. decrease in dissolved oxygen concentrations).
Date: 31 December 2022 - Train all relevant staff on the procedures developed in (b)1 and (b)2. In addition, ensure that all of the raw water teams, catchment teams, water quality scientists, and site production teams in the Ingbirchworth supply system are trained on changes in raw water quality, limnology, the bubble diffuser system, and the associated impacts on final water.
Date: 31 December 2022 - Evaluate the appropriateness of the draw off tower and abstraction point at Ingbirchworth IRE with consideration for the depth of the draw off location.
Date: 31 December 2023 - Evaluate the efficiency, functionality, maintenance schedule, and operational strategy of the bubbler system installed at Ingbirchworth IRE to ensure reservoir mixing to prevent thermal stratification and distribute oxygen throughout the water column to mitigate raw water quality deterioration.
Date: 31 December 2023 - Install and commission equipment to permanently provide information on water quality over the depth of the water column near the abstraction point of Ingbirchworth IRE to better inform the company’s raw water optimisation decisions. Consideration should be given for linking the equipment to the company’s telemetry system to improve the visibility of the thermal profile, dissolved oxygen profile and chlorophyll-α / phycocyanin concentrations in raw water sources supplying Ingbirchworth WTW.
Date: 30 April 2023 - Install additional on-line free chlorine measurement on the outlet of manganese contactor prior to final disinfection dose of sodium hypochlorite. Update SCADA and RTS telemetry systems with alarms as appropriate.
Date: 31 December 2022 - Review and update the procedures developed in (b)1 and (b)2 following completion of measures (b)4, 5, and 6, using the outputs of these measures to inform the review. Communicate any procedural updates to all relevant staff.
Date: 31 March 2024
(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: 31 October 2022 - 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 Ingbirchworth Water Treatment Works, 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. - Provide the mitigation plan for responding to changes in raw water quality as specified in (b)1 and confirm all relevant staff have been trained as specified in step (b)3.
Date: 31 January 2023 - Provide the escalation procedure for responding to changes in raw water quality developed as specified in (b)2 and confirm all relevant staff have been trained as specified in (b)3.
Date: 31 January 2023 - Provide a summary report on the assessment of the appropriateness of the existing draw off location and the evaluation into the need for additional draw off locations.
Date: 31 January 2024 - Provide a summary report of the efficiency, functionality, and appropriateness of the operational and maintenance strategy for the bubble in Ingbirchworth IRE, as specified in (b)5.
Date: 31 January 2024 - Confirm the installation and commissioning of the water column monitoring equipment in Ingbirchworth IRE, as specified in (b)6.
Date: 31 May 2023 - Confirm the installation and commissioning of the additional on-line free chlorine monitor on the outlet of the manganese contactor at Ingbirchworth works, as specified in (b)7.
Date: 31 January 2023 - Confirm completion of the review specified in measure (b)8 and provide evidence of any procedural updates implemented following the review, including evidence of communication of any updates to relevant staff.
Date: 30 April 2024 - Submit the audit strategy for auditing the effectiveness of the measures, as specified in measure (c)1.
Date: 30 November 2022 - 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 2025
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
23 August 2022
Reference: YKS-2022-00006 (V1)