South West Water Limited – AMP7 Littlehempston Water Treatment Works
Notice under regulation 28(4) of the Water Supply (Water Quality) Regulations 2016 (as amended)
Reference: SWT-2018-00005
Version Number: 3
Water undertaker as appointed under section 6 of the Water Industry Act 1991 (as amended): South West Water Limited, with registered number 02366665 (hereinafter called ‘the Company’).
Assets Affected:
- Littlehempston WTW, T6821F
- Littlehempston Supply System, Y6821
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 18 May 2018, which states that there is or has been a significant risk of supplying water from Littlehempston Water Treatment Works (and associated assets as applicable) that could constitute a potential danger to human health.
- 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 |
|---|---|---|
|
Pesticides |
Pesticides (Total by calculation) |
102932 |
|
Disinfection by-products |
Trihalomethanes (Total by calculation) |
106399 |
|
Earthy and musty taste and odour (and any related taste and odour descriptors) |
Taste (Taste Quant) |
104816 |
|
Earthy and musty taste and odour (and any related taste and odour descriptors) |
Odour |
107691 |
- 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:
- Enhanced operational monitoring.
Date: Ongoing for the duration of this Notice - Intermittent powdered activated carbon dosing as required and according to company procedures.
Date: Ongoing for the duration of this Notice - Blending of existing raw water sources.
Date: Ongoing for the duration of this Notice - Optimisation of the existing clarification and filtration processes to balance the needs of solids removal and removal of precursors to disinfection by-products.
Date: Ongoing for the duration of this Notice - Oxidisation of soluble manganese at the primary filtration stage.
Date: Ongoing for the duration of this Notice - Implement a risk-based approach to taste and odour mitigation incorporating PAC dosing based on:
- 2-methylisoborneol (MIB) and Geosmin trigger levels.
- Seasonal variations associated with taste and odour (T&O) compounds.
- Increased monitoring frequency based on environmental conditions.
- Review PAC efficiency for removing T&O compounds.
Date: Ongoing for the duration of this Notice
- Alternative supply strategies if PAC is considered ineffective.
Date: Ongoing for the duration of this Notice - Inform on-going raw water risk assessment by enhanced monitoring.
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:
- Complete a review to confirm steps to be taken and project completion dates.
Date: Complete - Plan and develop the outline design of the long-term solution. Award the full contract for the construction of the chosen solution.
Date: Complete - Develop the detailed design of the chosen solution.
Date: 30 November 2022 - Complete the commissioning of the chosen solution (GAC and UV) with all the GAC contactors available.
Date: 31 March 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 Littlehempston 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. - Completion of review of long-term measures to confirm the long-term solution.
Date: Complete - Complete the outline design of the final solution proposed. Confirm and evidence the award of the full contract for the scheme.
Date: Complete - Provide the detailed design of the chosen solution.
Date: 31 December 2022 - Completion of construction, installation, and commissioning of the long-term solution.
Date: 30 April 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: 31 May 2026
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
Nick Adjei
Deputy Chief Inspector, on behalf of the Secretary of State for Environment, Food and Rural Affairs
12 May 2022
Reference: SWT-2018-00005 (V3)