Investigations

This section contains summaries of reports on drinking water
quality incidents and investigations.

Report on drinking water quality incident at:
Inverinate Water Treatment Works in April 2007

Scottish Water Executive Summary

Inverinate Water Treatment Works (WTW) comprises of disinfection of surface water extracted from the River An Leath Ault. The WTW supplies 43 properties with approximately 35 m≥ of treated water daily via a 35m≥ clear water tank (CWT).

On arrival at site to carry out task scheduling on Tuesday, 10/04/07, the operative noted that despite all aspects of the disinfection system working as normal, there was no free chlorine in the water going into supply.

Lack of free chlorine going into supply was due to poor raw water quality increasing chlorine demand. Action was taken to increase chlorine in the CWT and increase the chlorine dose at the WTW. Microbiological samples taken in response to this incident passed.

As a result of this incident the WTW will be visited daily by the operative until the site is mained out from Kyle WTW, currently forecast to be by 31st December 2007.

DWQR Assessment on the incident

The DWQR's assessment of this incident is that it was caused by bad weather resulting in poor raw water quality. The poor raw water quality would increase the demand for disinfection, but since the system can only be adjusted manually, it has to wait for a routine visit from the operator to carry out these adjustments. DWQR notes that Scottish Water will now visit the site daily until the works is abandoned and the area supplied by the Kyle works by the end of 2007, subject to agreements on land purchasing and the relevant water abstraction licence being in place.