Waste Management System. Procedure for backwashing at Cofield Swimming Pool and associated record keeping Corporate Procedure: CP-WMS 005 Authorised by: Issue number: Three Date of issue: 12 th May 2010 Purpose To define the University of Sheffield s legal obligations and procedures associated with the backwashing at Cofield Swimming Pool. Scope This procedure applies to the regular backwashing of Cofield Pool. Legal framework Water Industry Act 1991 Health and Safety at Work Act 1974 Health and Safety at Work Regulations 1999 Responsibilities Technical services / Swimming Pool Maintenance Technicians Day to day running of the pool. Assistant Electrical Engineer Maintenance of plant, equipment and machinery. U Sport Facilities manager and U Sport Employees To ensure the pool is cleaned regularly to a satisfactory standard and that emergencies are reported to the relevant members of staff and recorded using corporate systems. Environment Officer Legal compliance and internal audit.
Procedure 1. Trade effluent discharges 1.1 No more than 40 cubic meters of effluent can be discharged in any 24 hour period. The rate of discharge must not exceed 5 litres per second. 1.2 The volume of water used and discharged to the sewer is recorded. A water meter records gallon of water used to make up the pool, and second meter measure litres discharged (footbath valve). The pool is made up once a day and although water is discharged throughout the day. 1.3 The following chemical and physical properties of the discharge are set out in the schedule of the consent. Temperature ph Settleable solids Settled chemical oxygen demand Free chlorine 1.4 Tests are not carried out for settleable solids and settled chemical oxygen demand. Provided the pool is backwashed weekly, the thresholds set in the consent to discharge will never been exceeded. 1.5 The IRSM publication Plant Operators Guide sets out the range that the chemical and physical properties must fall within. These are well within the range that the consent to discharge sets for these properties. 2. Routine backwashing frequency 2.1 The swimming pool is backwashed at least once a week. 2.2 Routine backwashing takes place on a Saturday evening when the pool has closed. 2.3 To keep the backwashing frequency to a minimum, poolside attendants must regularly brush clean the pool floor and sides. 2.4 Additional backwashes maybe required due to emergency situations. If an emergency backwash was needed during the later part of the week then the routine backwash on Saturday will not be conducted. 2.5 The backwash takes about 6-8 minutes (until the water in the sight glass runs clear). 3. Procedure for backwashing 3.1 Only Swimming Pool Maintenance Technicians that have passed the National Pool Plant Operators course are qualified to carry out backwashes. Backwashing can only take place when the pool is closed. Page 2 of 5
3.2 When backwashing the following procedure should be followed. CLOSE make up valve CLOSE scum valve Re-grc pump CLOSE suction and delivery valves CHANGE OVER duty re-grc pump CLOSE inlet valves CLOSE outlet valves CLOSE main outlet valve main drain valve (check sight glass) washing valve 1 (front) suction and delivery valves on pump SWITCH ON pump (wait until sight glass clears) pump CLOSE washing valve 1 (front) washing valve 2 (back) SWITCH ON pump (wait until sight glass clears) pump CLOSE washing valve 2 (back) CLOSE main waste valve small drain valve outlet valve 1 drain for two minutes close outlet valve 2 drain for two minutes close CLOSE small drain valve outlet 1 and 2 valves main outlet valve CLOSE main suction valve CLOSE pump suction and delivery valves CHECK scum and make up valves closed DRAIN strainer/aluminium pot remove and clean strainer DOSE with aluminium and replace lid main suction valve pump suction and delivery valves inlet valve outlet valves 1 and 2 VENT air out of filter BALANCE Re-grc pump SWITCH ON autodoser PUT make up on as required to top swimming pool up ADD calcium and sodium bicarbonate directly to the pool 4. Chemical dosing 4.1 Chemicals are added to the pool (either manually or automatically); the Plant Operators Guide sets out the range that the chemical parameters must fall within. These are well within the range that the consent to discharge sets for these parameters 4.2 Aluminium sulphate is added manually into the dosing pot after the backwash. Page 3 of 5
4.3 Calcium hypochlorite and sodium bicarbonate are added directly to the pool as and when required by an automatic dosing machine. If the dosing machine fails then the pool is shock dosed. 4.4 The automatic dosing machine adds carbon dioxide gas to the pool water to regulate the ph levels. 5. Manual testing and automatic monitoring 5.1 The electronic monitoring machine (Depotox Pool) measures ph, temperature and chlorine. If the ph of the pool water exceeds 7.6 the ph probe would be recalibrated and if necessary, replaced. 5.2 Tablet test kits are used to verify the electronic monitoring equipment. Water samples should be taken from the sample point next to the Depotox Pool machine. The performance of the electronic equipment is monitored three times a day against the manual tests. 5.3 The relationship between the two types of testing and their results should be consistent and understood by the pool operators. 5.4 Manual testing should be undertaken at the following frequency Mon to Fri 6.30 8.30 10.30 12.30 14.30 16.30 18.30 Sat and Sun 8.30 10.30 12.30 14.30 16.30 5.5 Only Swimming Pool Maintenance Technicians that have passed the National Pool Plant Operators course are qualified to carry out tablet tests. 5.6 Test kits should be kept scrupulously clean and separate tubes should be used for ph and disinfectant testing. 5.7 Test kits should be stored and used according to the manufacturer s instructions. Reagents should be disposed of when they has passed their use by date / shelf life. 5.8 Only the test kits manufacturers specified tablets should be used. 5.9 A test kit with the applicable range for the water under test should be used. 5.10 If the first test gives a result that does not fall within the expected parameters, or falls at the top or at the bottom of the kit s range, then a second sample and test should be completed using a new batch of tablets. If the second test verifies the first set of results then the reasons for this must be investigated immediately and if necessary the emergency procedure should be activated. 6. Record keeping 6.1 Records are kept to demonstrate compliance with the consent to discharge and for Health and Safety reasons. 6.2 Sheffield City Council Environmental Heath department test the pool water quality every three months. Environmental Health test the water for a range of properties, including ph, combined chlorine, total dissolved solids and bacterial load. Records of Environmental Health visits and any subsequent actions are kept by the Mechanical Engineer. Page 4 of 5
6.3 Records must be kept indefinitely. 7. Pool and plant maintenance 7.1 Sterling Hyrdo Tech has the maintenance contract for the chemical dosing meter, the CO2 meter and the chlorine and ph probes. The meters and probes are serviced/calibrated twice a year. Sterling Hydro Tech leave records which are kept by the Mechanical Engineer. 7.2 The ph sensors on the automatic equipment should be recalibrated when the tablet tests show the sensor to be out of calibration. 7.3 Recalibration of the sensor must only be undertaken by competent personnel. If it is not possible to recalibrate the sensor then it should be replaced. Records of all recalibration and sensor replacement should be made in the day book. 7.4 A spare sensor must be kept in store. 7.5 Filters are refurbished as they are required. 7.6 If the pool requires draining for any maintenance, Yorkshire Water will be informed when the pool water will be discharged and any instructions given will be followed. 8. Training and qualifications 8.1 All employees will receive training appropriate to their function and level so they are aware of the importance of conformance with swimming pool management procedures, their responsibilities and the consequences of departing from operating procedures. 8.2 Personnel performing tasks with significant operational or safety impacts should be competent on the basis of education, appropriate training and / or experience. 8.3 All Swimming Pool Maintenance Technicians must attend and pass the National Pool Plant Operators course. 8.4 Swimming Pool Maintenance Technicians must receive training on how to complete tablet test kits and what to do if test results are unexpected. 8.5 Personnel training records will are kept by admin sections. Associated Documentation Trade Effluent Discharge to Sewer Consent Number Y/2876/08C PAS 39: 2005 Management of public swimming pools Water treatment systems, water treatment plant and heating and ventilation systems Code of Practice Plant Operators Guide Institute of Sport and Recreation Management Appendices Cofield Pool Log Sheet Monday to Sunday Plant Reports Weekly Summary Sheet Day book Page 5 of 5