9 FOLKESTONE AND DOVER WATER SERVICES LIMITED
Introduction
Folkestone and Dover Water Services Limited supplies on average about 49 Ml/d of water to about 160,000 consumers in the coastal strip from Dungeness to Dover on the Kent coast. Principal population centres are Dover, Folkestone, Hythe and New Romney in the Dover and Shepway districts. The Company also supplies local industry including the Dungeness Power Station, Dover and Folkestone Harbours and the Channel Tunnel. 75% of the Company’s water supplies comes from boreholes in the chalk aquifer, and over 20% comes from the Dungeness shingle headland. The remainder is derived from the Folkestone and Hythe beds in the Lower Greensand. The Company has 15 treatment works, and distributes water through 1,068 km of pipes and 13 service reservoirs to 10 water supply zones.
Overall water quality
At water treatment works and service reservoirs and in water supply zones, the Company carried out a total of 7,302 determinations in 2000. Of these, 99.96% demonstrated compliance with the relevant PCV, but three showed a contravention to have occurred.
Coliforms were not detected at 14 (93%) of the Company's 15 water treatment works. At all of the Company's 13 service reservoirs, coliforms were absent from at least 95% of samples. Of the Company's 10 water supply zones in 2000, all complied fully with the relevant water quality standards or had a breach of a standard which was considered trivial.
Microbiological quality of water leaving treatment works
The Company complied with the sampling frequencies required by regulation 17 at all of its treatment works in 2000.
Table 9.1 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. Differences over the last three years in the number of treatment works, and samples from treatment works in which coliforms were detected are not considered significant.
Contraventions of the microbiological quality standards at one works have been considered trivial.
Microbiological quality of water in service reservoirs
The Company complied with the sampling frequencies required by regulation 18 at all of its service reservoirs in 2000.
Table 9.2 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. Differences the last three years in the number of service reservoirs, and samples from service reservoirs, in which coliforms were detected are not considered significant.
There were no contraventions of the microbiological standards at any of the Company's service reservoirs in 2000.
Water quality in water supply zones
The Company complied with the required sampling frequencies for all parameters in all zones.
Table 9.3 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. Differences over the last three years are not considered significant.
The single contravention of the standards in one zone is considered trivial.
Inspection
Audit trails of five samples
Mr R M Walls, Consultant, working under the direction of Mr W M Waite, Principal Inspector carried out audit trails on five samples chosen at random. Based on Mr Walls report Mr Waite concluded that:
The sampling and analytical arrangements are generally satisfactory. However the inadequate checks on the instrument used to measure metals would make the result for aluminium doubtful. This has been rectified since the date of the sample audited. The analytical results have appeared on the Public Record in time.
Audit of plumbosolvency treatment and control programmes of work
In November 2000, Consultants WS Atkins, represented by Mr S Ntifo, working under the direction of Mr P Halton, Inspector, carried out an audit of the Company as part of the Inspectorate’s work in agreeing with water companies’ their programmes of works to secure compliance with new lead standards. Based on Mr Ntifo’s report, Mr Halton concluded that:
the Company’s process of sites/scheme selection for plumbosolvency treatment and/or optimisation measures is sound;
the integrity of the data submitted to the Inspectorate and used for assessing plumbosolvency was largely confirmed;
the schemes audited are justified on water quality reasons; and
the Company’s proposed steps to be taken and the proposed completion dates are generally sound.
Review of procedures for operation and maintenance of the distribution network
In December 2000, Consultants Binnie, Black and Veatch working under the direction of MrW M Waite, Principal Inspector carried a follow up investigation of the recommendations made during the 1999 audit of the Review of Procedures for Operation and Maintenance of the Distribution Network. Based on their report Mr Waite concluded that:
that to provide adequate responses to those recommendations where the response has been considered inadequate, the company extend its procedures to provide the following:
- Specific guidance on the rate of valve operation for valves of different diameters and with different differential pressures (Recommendations R1.2 - Implementation and monitoring, R2.3 - Recharging after Completion of the Maintenance or Repair and R9.1 - Guidance). The company consider that their staff are sufficiently well trained to operate valves in a correct manner but undertook to consider extending the procedure to include guidance on the maximum rate of operating valves and monitoring velocities during their operation by listening.
- Specific guidance on the criteria used to determine the duration for which hydrants are flushed (Recommendation R3.3 - Implementation and Monitoring).
- Guidance on the sampling and analysis requirements following a discolouration incident (Recommendation R5.3 - Sampling and Analysing). The company has undertaken to add guidance on sampling either in the procedure or by reference to their existing Water Quality Manual.
- Guidance on the maximum flows for different diameters to prevent discolouration and specific reference to checking for reverse flow in the analysis (Recommendation R7.1 - Network Model Application).
- A procedure on the routine monitoring of the status of valves and on the condition of their markers (Recommendation R8.3 - Monitoring of Valve Status). The company stated that they do not have any plans to introduce routine monitoring of the status of valves at the present time.
Follow-up of response to recommendations
The Inspectorate audited the Company’s responses to recommendations made during earlier inspections and audits. The Inspectorate concluded that:
Sampling and analytical arrangements are generally satisfactory. However the inadequate checks on the instrument used to measure metals would make the result for aluminium doubtful This has been rectified since the date of the sample audited;
The analytical results have appeared on the Public Record in time; and
The Company has taken satisfactory action on each of the recommendations made in 1999.
Inspection of distribution system improvement programme progress
In September 2000, Consultants RPS, represented by Dr S Tooms, working under the direction of Mr P Halton, Inspector, carried out an audit of the Company’s progress with the mains renovation set out in the distribution Undertaking submitted by the Company. Based on Dr Tooms’s report, Mr Halton concluded that:
The objectives of the undertaking remained valid;
the steps to be taken were defined with adequate precision:
a practicable timetable has been set; and
the Company was likely to meet the target renovation length by the date for completion of the work.
As a result of these inspections, 11 recommendations were conveyed to the Company for formal response. The Company has already taken action or is taking actions on the recommendations.
Improvement programmes
No undertakings in respect of improvement programmes accepted by the Secretary of State from the Company were due for full completion or the completion of major steps during 2000.
The ongoing distribution system improvement programmes due for completion in 2010, which have been implemented by the Company, have been progressing satisfactorily.
Incidents
Both of the events notified during 2000 by the Company to the Secretary of State under the terms of the Water Undertakers (Information) Direction 1998 were regarded by the Inspectorate as constituting incidents in which drinking water quality demonstrably deteriorated. Both incidents have been assessed.
The first involved the supply of water with a taste and odour and which was also discoloured, to parts of Hawkinge in October. The second involved wholesomeness concerns following low level bacteriological failures in the water leaving Kingsdown pumping station to parts of the Downsgate zone in November. The Company took all reasonable steps to protect consumers during each of the above incidents and has also responded positively to the single recommendation made by the Inspectorate.
No other events regarded as constituting incidents came to the attention of the Inspectorate in 2000.
Enforcement action
No enforcement action needed to be considered for the Company as a result of the Inspectorate's work in, or pertaining to, the calendar year 2000.
table 9.1 Folkestone and Dover Water Services Limited
MICROBIOLOGICAL QUALITY OF WATER LEAVING TREATMENT WORKS2000 1999 1998 Number of water treatment works 15 19 19 Works with no sampling shortfall 15 19 19 COLIFORMS Total number of determinations 1,234 1,400 1,428 - number containing coliforms 1 0 2 - % containing coliforms <0.1 0.0 0.1 Treatment works with coliforms detected 1 0 2 - % of all works 6.6 0 11 FAECAL COLIFORMS Total number of determinations 1,234 1,400 1,428 - number containing faecal coliforms 1 0 1 - % containing faecal coliforms <0.1 0.0 0.1 Treatment works with faecal coliforms detected 1 0 1 - % of all works 6.6 0 5
table 9.2 Folkestone and Dover Water Services Limited
MICROBIOLOGICAL QUALITY OF WATER IN SERVICE RESERVOIRS2000 1999 1998 Number of service reservoirs 13 13 13 Service reservoirs with no sampling shortfall 13 13 13 COLIFORMS Total number of determinations 665 675 672 - number containing coliforms 0 1 0 - % containing coliforms 0.0 0.1 0.0 Service reservoirs with coliforms detected 0 1 0 Service reservoirs with coliforms detected in more than 5% of samples 0 0 0 - % of all service reservoirs 0 0 0 FAECAL COLIFORMS Total number of determinations 665 675 672 - number containing faecal coliforms 0 0 0 - % containing faecal coliforms 0.0 0.0 0.0 Service reservoirs with faecal coliforms detected 0 0 0 - % of all service reservoirs 0 0 0
table 9.3 Folkestone and Dover Water Services Limited
WATER QUALITY IN SUPPLY ZONESColumns 'CBU' show, for determinations, contraventions covered by undertakings and, for zones, the total number of zones covered by undertakings in 2000. Column 'E' shows the number of zones for which new enforcement action is under consideration as a result of contraventions of the PCV in 2000. Please refer to the Introduction to Part 2 for more detailed explanation of this table. PARAMETER DETERMINATIONS in 2000 ZONES (10 in 2000)* Total Contravening PCV Non-compliant No. % CBU CBU E Number in: 2000 2000 1999 1998 Coliforms 590 0 0.0 0 0 0 0 0 0 Faecal coliforms 590 0 0.0 0 0 0 0 0 0 Colour 64 0 0.0 0 0 0 0 0 0 Turbidity 147 0 0.0 0 0 0 0 0 0 Odour 64 0 0.0 0 0 0 0 0 0 Taste 64 0 0.0 0 0 0 0 0 0 Hydrogen ion 264 0 0.0 0 0 0 0 0 0 Nitrate 70 0 0.0 0 0 0 0 0 0 Nitrite 65 0 0.0 0 0 0 0 0 0 Aluminium 64 0 0.0 0 0 0 0 0 0 Iron 147 0 0.0 0 0 0 0 0 1 Manganese 64 0 0.0 0 0 0 0 0 0 Lead 22 1 4.5 0 0 0 1 0 0 PAH 64 0 0.0 0 0 0 0 1 2 Trihalomethanes 13 0 0.0 0 0 0 0 0 0 Total pesticides 91 0 0.0 0 0 0 0 0 0 Other pesticides 351 0 0.0 0 0 0 0 0 0 All others 770 0 0.0 0 0 0 0 0 0 TOTAL 3,504 1 0.1 0 - - - - - *10 zones in 1999; 10 zones in 1998.
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Drinking Water Inspectorate,
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Published 11 July 2001
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