Hull City Council Drinking Water Fluoridation Feasibility Report – Stage 1 Summary Report

Project: 2366682

Final

th 7 November, 2016 Document Control

Title - Hull City Council - Drinking Water Fluoridation Feasibility Report – Stage 1 – Summary Report Ref: 2366682 Revision Prepared by Checked by Draft V1 – 30 Oct 2016 CH JH Final – 7 Nov 2016 JH

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1 Introduction

1.1 Commissioning of Yorkshire Water and Arup to undertake a feasibility study

“The Health and Well-being Board of the City of Kingston upon Hull has concerns about poor dental health in Hull children, and specifically about levels of dental decay. The Board, advised by the Oral Health Advisory Group, wishes to examine evidence-based options for addressing this problem. Amongst possible options may be community water fluoridation (CWF). In the first instance, and without commitment, it is desired to gain an understanding of whether CWF would be technically feasible for Hull, an indication of costs, and the extent to which any scheme might need to extend beyond the City boundary to be technically viable.

Public Health England (PHE) holds, on behalf of the Secretary of State for Health, the legal agreements with water companies for all CWF schemes in England. PHE has supported the City’s Director of Public Health to develop a specification for a phased feasibility assessment from Yorkshire Water Services Ltd (Yorkshire Water) to assist those deliberations.”

1.2 Specification for the study.

1.2.1 Meeting legislative requirements.

Community water fluoridation is governed by specific legislation within the Water Industry Act 1991 as amended most recently by the Health and Social Care Act 2012, together with secondary legislation in The Water Fluoridation (Proposals and Consultation)(England) Regulations 2013 and The Water Supply (Fluoridation Indemnities)(England) Regulations 2005.

Under that legislation, a local authority which has made a formal proposal for a fluoridation scheme has to consult the water undertaker and ascertain its views as to whether the arrangements which would result from implementing the proposal, insofar as they might affect the water undertaker, would be operable and efficient [Water Industry Act 1991, section 88C(3)].

Kingston upon Hull has not made such a formal proposal and may not do so. Nevertheless, in order to aid the appraisal of options and decision-making by the Health and Well-being Board, it is important that Yorkshire Water, in carrying out each phase of this feasibility assessment, ensures that the scope and content would enable the company to certify in due course that the arrangements described would be “operable and efficient” insofar as they might affect the company. In submitting the completed report on the final phase of the feasibility assessment, the company will be required to confirm that any fluoridation arrangements described therein would meet that test.

The legislation also requires a formal fluoridation proposal to specify the area or areas which, under the proposal, would receive water in which the fluoride content had been increased [Act, s88B(2)]. Additionally, it is necessary for the proposer to know whether the proposal would affect any other local authority [Act, s88D]. It is therefore also important that Yorkshire Water identifies the area(s) which would be affected by any scheme(s) identified through the feasibility study, both in terms of geographical coverage [including in

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relation to local authority boundaries] and population size covered by the identified scheme(s)[again by local authority].

1.2.2 Scope of the study

The feasibility study process is to be split into three phases so as to minimise expenditure on levels of detail which may be found to be unnecessary. The phases (if all commissioned) would comprise:

1. An initial desktop identification of WQZs, affected LAs and affected populations, together with potential locations for fluoridation plants, with some narrative about water flows and general resilience. This phase might identify a number of possible options for initial discussion with Hull City Council and Public Health England. 2. Develop estimates of costs for selected options based on “off the shelf” cost estimates. 3. A full engineering feasibility study in relation to preferred option(s) to identify water flows, resilience issues, numbers of households affected by LA, scope of works for fluoridation plants and costs.

In undertaking the Phase 1 study it became clear that to answer the questions raised, most of the information required to answer Phase 2 was identified and developed; this information is therefore provided in this report.

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2 Yorkshire Water - water production & distribution

2.1 Overview

Yorkshire Water operates a complex grid network, allowing treated water to be moved around their supply area. Whilst this ensures water supply resilience, it means that any given area could be supplied by a number of different water treatment works (WTW), singly, or in combination, which may change throughout the year.

Whilst the above Grid system is of significant benefit in ensuring the resilience of water supplies to the Region, it adds complexity in dealing with situations such as the subject of this report. In developing the scenarios YWS has proposed solutions which do not compromise the resilience of supplies to Hull CC residents, or any other authorities.

2.2 Hull area water sources

The water treatment works feeding Hull are supplied by both river and groundwater sources. There are three main WTWs for water supplies to the City of Hull and Holderness areas:

 Keldgate water treatment works (WTW) generally supplies West and Central Hull  Tophill Low WTW generally supplies East Hull and Holderness  Loftsome Bridge WTW generally supplies West Hull, under normal circumstances after blending with water at Keldgate CRE.

In undertaking this study we identified that Loftsome Bridge WTW supplied little of the Hull CC area directly, and that the very large area of overspill it gave rise to was likely to overweigh the benefits of providing dosing to those areas. Dosing of fluoride at this site has not been considered further.

2.3 Details of the Hull Water Supply relevant to potential fluoridation schemes

The base-load flow is delivered from Tophill Low WTW (THL). A diurnal flow set point from THL allows a change in flow to meet the demands of customers whilst balancing the optimal operation of the WTW. Once the demand for water exceeds that produced by THL WTW the additional variable flow to meet it is provided by controlled gravity feeds from Keldgate WTW, and if required from Loftsome Bridge WTW. Water then enters the City via three groups of strategic mains, each of which is metered and the flow of water managed by automatically controlled valves. The pressure in the City is controlled at a ‘critical node’ with a diurnal pressure profile set-point; feedback from this modulates the automated valves to maintain the desired pressure.

The flexibility of this system is key to maintaining supplies to the City and surrounding areas under a range of scenarios, and must not be compromised by any proposed fluoridation scheme. This is consistent with the obligations of Yorkshire Water under the Water Act.

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In addition to supplying the City, there are a number of exports from the supplying WTWs, prior to water entering the HCC area, or where water is subsequently exported to ERYC areas. Principally these are:

 from Tophill Low WTW:- a supply to the area East toward the coast at Hornsea  From Hull Town Pressure System: - supplies provided directly to Salt End and beyond, and to the Holderness Peninsula

The former can be addressed by a change in dosing arrangements, the latter cannot, without major disruption and expense, and potential loss of resilience of water supplies.

2.4 Overview of previous fluoridation study

A previous Regional study (undertaken on behalf of Public Health England) identified that, in order to provide full coverage of the City of Hull consistently, a fluoridation scheme would involve providing dosing facilities for water produced at all three of the above WTWs. In turn this resulted in fluoride dosed water entering the areas served by the following local authorities:

 Hull – the target area,  East Riding,  North Yorkshire (Ryedale, Selby),  York

The likely extent of overspill into other Authority areas was identified; some areas eg the M62 corridor received the target fluoride dose, others, particularly those to the East of York, received some fluoride, but for most of the year this would be very significantly below the target concentration.

Amongst others, one of the aims of this current specific feasibility study was to identify the means by which some of the above issues could be resolved and provide more targeted dosing arrangements.

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3 Proposed fluoride dosing locations

3.1 Overview

In the following sections of the report we identify the limits of what can be achieved by means of introducing fluoride at water treatment works sites only, and, as an alternative the potential to tailor dosing more closely to the City of Hull boundary by introducing fluoride at other potential dosing points. As previously stated, we believe that dosing of fluoride at Loftsome Bridge WTW is not cost effective, supplying a very low population in Hull directly, and being responsible for a very significant area of overspill into ERYC area. With these caveats, the following sections identify the two dosing scenarios which are feasible and operable and give HCC options to inform the debate around dosing.

3.2 Fluoride dosing - undertaken at existing YWS sites

Indicative locations within existing YWS sites and assets for the fluoride dosing installations have been identified on the basis of available space, access for delivery tankers, proximity to utilities and proximity to suitable dosing injection points. These locations are based on a review of as-built record drawings and general arrangements from our records, along with satellite imagery.

3.2.1 Keldgate WTW

On initial investigation of the Keldgate site and supply area it was identified that, although fluoride addition at the WTW was feasible and operable, it would give rise to a significant area of overspill. This would include the town of Beverley and the Little Weighton area within ERYC authority area. It is proposed that dosing be considered at Keldgate CRE which is a YW site adjacent to Keldgate WTW. This would remove this overspill from the scheme, with limited cost increase and no impact on the efficiency of YW operations.

On this site some of the major trunk mains leaving the site are adjacent to each other and can use a common dosing building. A further trunk main would require a separate dosing station located at the northern side of the site.

3.2.2 Tophill Low WTW

At Tophill Low WTW dosing into a trunk main will use a single dosing station

The following table identifies the range of flows to which each dosing point is capable of providing fluoride addition. The average amount of fluoride chemical dosed is also provided.

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Figure 1:- Dosing point flow-rates & chemical consumption

Figure 2:- Dosing point chemical storage & chemical dosing capacities

3.2.3 Scheme costings

In identifying the costs of installation and operation we have followed the approach of:

 CAPEX for dosing equipment etc – based on maximum flowrates  OPEX for chemical consumption etc – based on annual average flowrates

CAPEX £1.61m

OPEX - Maintenance £80.5k pa

OPEX - Chemicals £210k pa

OPEX – Ops £38.21k pa

OPEX – total £328.71 pa

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3.2.4 Population impacted by scheme

The table below identifies the populations impacted by this dosing variant.

Figure 3:- Populations impacted by scheme – HCC/ERYC populations & deprivation Quintiles

3.2.5 Area impacted by scheme

The map below indicates the area which would be provided with fluoride dosed water supplies (red line), together with the boundary of Hull City Council’s administration (green line), and the current water supply zone boundaries (coloured infill).

Figure 4:- Areas impacted by scheme – Dosing at WTWs only

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3.3 Fluoride dosing - undertaken at non-YW sites

In developing this proposal we have aimed to balance the feasibility and operability of the fluoride dosing scheme with the requirement to minimise the overspill of fluoride dosed water into neighbouring authority areas (ERYC).

We have assumed that Planning would not be a significant hindrance to the promotion of such a dosing scheme, and that HCC would support any such requirements – as YW would not be able to use deemed consent in developing these sites. We have also had to assume that land purchase will be negotiable at the appropriate site.

Indicative locations close to the boundary of HCC Authority’s area and adjacent to YW assets have been identified for the fluoride dosing installations. The locations have been identified on the basis of available space, access for delivery tankers, proximity to utilities and suitable injection points. These locations are based on a review of general arrangements from our mapping records, along with our mains record.

3.3.1 Trunk main dosing points

This approach provides fluoride addition to the same trunk main systems as discussed in 3.2 above; however the locations are nearer to the City boundary and as such allows the dosing to target HCC population more precisely. It avoids provision of fluoride dosed water into conurbations such as Cottingham which abut the Authority area. This approach would remove this overspill from the scheme, with limited impact on YW operations. It does however increase the installation costs.

The locations are indicative only at this stage and would require a more detailed engineering assessment as part of any further investigation phase. However, they indicate what could be achievable by the use of alternative dosing points.

The following table identifies the range of flows to which each dosing point is capable of providing fluoride addition. The average volume of hexafluorosilicic acid solution to be dosed is also provided.

Figure 5 Dosing point flow-rates & chemical consumption

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Figure 6 Dosing point chemical storage & chemical dosing capacities

3.3.2 Scheme costings

In identifying the costs of installation and operation we have followed the approach of:

 CAPEX for dosing equipment etc – based on maximum flowrates  OPEX for chemical consumption etc – based on annual average flowrates

CAPEX £2.02m

OPEX – Maintenance £101k pa

OPEX – Chems £190k pa

OPEX – Ops £38.21k pa

OPEX – total £329.21k pa

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3.3.3 Population impacted by scheme

This approach to providing the target fluoride concentration to the HCC authority area has the impact of reducing the overspill population by 37,925.

Figure 7:- Populations impacted by scheme – HCC/ERYC populations & deprivation Quintiles

3.3.5 Area impacted by scheme

The map below indicates the area which would be provided with fluoride dosed water supplies (blue line), together with the boundary of Hull City Council’s administration (green line), and the current water supply zone boundaries (coloured infill).

Figure 8:- Areas impacted by scheme – Dosing at alternative sites

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3.4 HCC Population not included in the scheme

As dosing at Loftsome Bridge WTW and Raywell CRE have been excluded from the feasible scheme there are two DMAs in West Hull which would not receive the target concentration of fluoride. A more detailed investigation may reveal options to reconfigure the local distribution network to allow these to be supplied from an alternative direction. The graphic below identifies these areas; should it be imperative that they are supplied then that investigation can be included in any future study. For the purposes of this study the excluded population is estimated at 4,160.

Figure 9: Area not able to be provided with fluoride at the target concentration

3.5 Potential for further reduction in overspill areas

At the level of investigation undertaken as part of this Feasibility Study it has not been possible to identify logical options which would reduce the supply of fluoride dosed water to the East of the HCC authority area and over into Holderness. Without considering removal of fluoride at the boundary of the authority’s area, we cannot identify a logical solution to this issue.

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Appendix 1 Mapping of Option 1 – WTW based dosing

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Appendix 2 Mapping of Option 2 – Distribution based dosing

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