Chamber and committees

The methodology used by Scottish Water to identify and count cryptosporidium oocysts is set out in The Cryptosporidium (Scottish Water) Directions 2002 and the associated guidance. These documents are available from the Parliament's Reference Centre (Bib. numbers 22767 and 24367 respectively). Scottish Water does not type oocysts because this is a highly specialised task that is still being developed for oocysts detected in water samples.

I have asked Dr Jon Hargreaves, Chief Executive of Scottish Water to respond. His response is as follows: The project agreement requires measures to be taken to achieve standards of odour treatment. Any failure of this process causing an odour nuisance event is recorded as a service level failure and a deduction from the service fees is applied. Failure also triggers a system of penalty points which, if failure continues, can accumulate to a level to cause termination of the contract.

I have asked Dr Jon Hargreaves, Chief Executive of Scottish Water to respond. His response is as follows: Permissible levels of odour were determined by the planning authority and incorporated into the planning consent. This requires the works to be designed and operated so that the contribution of the works to odour concentration does not exceed 2.5 odour units/m³, 98% of the time.

Speciation of cryptosporidium oocysts is highly specialised work and is not routinely undertaken as part of the analysis work carried out on water samples.

Scottish Water regularly checks the quality of all Glasgow's drinking water as required by The Water Supply (Water Quality) (Scotland) Regulations 1990. Continuous sampling of the water from Milngavie treatment works for cryptosporidium is also carried out under the terms of The Cryptosporidium (Scottish Water) Directions 2002. The Milngavie water treatment works serves about 700,000 people in the Greater Glasgow area.

I have asked Dr Jon Hargreaves, Chief Executive of Scottish Water to respond. His response is as follows:The pipeline from Dalmuir to Shieldhall has been tested with sludge since the 20 August 2002. The pipeline became fully operational on the 9 September 2002 and now all the sludge from Dalmuir is pumped to Shieldhall for onward pumping and processing at the new Daldowie Sludge Treatment Centre.

I have asked Dr Jon Hargreaves, Chief Executive of Scottish Water to respond. His response is as follows: Hydrogen sulphide levels are monitored at the emission stack of the odour treatment plant. The plant started its commissioning process last year but experienced faults in the instrumentation and control systems. These have been addressed, and over the last six months the plant has been operating more reliably. Monthly peak levels of hydrogen sulphide were 90ppb, measured on a 15 minute sampling cycle, with monthly averages from 4ppb to 22ppb. Intensive monitoring of boundary odours will be carried out during the contractual six month odour investigations.

I have asked Dr Jon Hargreaves, Chief Executive of Scottish Water to respond. His response is as follows:The works achieved discharge compliance on 7 February 2002. This is a measure of the ability of the works to meet the required discharge consent standards set by the Scottish Environment Protection Agency. Since then, work has progressed commissioning the remainder of the plant, equipment and control systems, and setting the operational parameters for the long term running of the treatment works. The contract with Scotia Water allows for this commissioning process until the next stages of practical completion and actual completion are reached. Scotia Water has committed resources to achieve these contractual milestones and has issued a programme showing practical completion by mid-December 2002, and actual completion by the end of January 2003.

In my response of 5 July 2002 to the member's letter of 31 May about the proposed timetable for the preparation of the consultation code, I explained the process required under section 28 of the above act, before the code was submitted to Scottish ministers.In this respect, I refer the member to the answer given to question S1W-28185 on 30 August 2002. All answers to written parliamentary questions are available on the Parliament's website, the search facility for which can be found at http://www.scottish.parliament.uk/webapp/search_wa.The consultation code has not been submitted to ministers.

I have asked Dr Jon Hargreaves, Chief Executive of Scottish Water to respond. His response is as follows:Odours from the plant have come principally from the interim sludge processing operation, the transport of the sludge cake and from the storm tanks.The interim sludge processing was stopped on 13 September and the sub-contractor was instructed to clean out the remaining sludge from his storage tanks before standing down. As the sludge is heavy and grit laden at the bottom of these tanks, decommissioning is likely to last until the second week in October. Sludge is now being pumped to Shieldhall waste water treatment works through Scottish Water's new pumping station at Dalmuir.The trucks transporting the sludge cake were also a source of odour nuisance. This was caused by the release of ammonia as a result of the lime addition required for agricultural recycling of the material. Scottish Water took over the management of cake disposal from the beginning of July. An alternative disposal route was found which did not require the addition of the lime and this has reduced the nuisance considerably.The storm tanks have proved to be a source of odour nuisance particularly during emptying. Prolonged periods of wet weather over the last 12 months caused a large accumulation of sludge in the tanks and caused problems with both the volume to be cleared, and deterioration in sludge quality as the sludge aged and turned septic. Settled weather during the last month has only now allowed all the tanks to be cleaned. In light of experience, Scotia Water has alleviated some nuisance by modifying its operating procedures to limit exposure of sludge to the atmosphere and return tank contents to the head of the works at an early stage. Discussions have also been held with the Scottish Environment Protection Agency on using the tanks more effectively and if agreement is reached, the tank operation will be simplified and the odour risk reduced.