Attachment 1 to Report No. 99.728 Page 1 of 38 Water Supply (October 1999) Attachment 1 to Report No. 99.728 Page 2 of 38 Operations Group (October 1999) Attachment 1 to Report No. 99.728 Page 3 of 38 Operations Group Review of Operations For the Period Ended 31 October 1999 1. Items of Note ? The plant optimisation trials at Te Marua and Wainuiomata are proceeding well. Full scale plant trials at Te Marua have been completed and excellent results have been obtained. The trials at Wainuiomata have identified various improvements, which are being implemented. ? Algae growth in the lakes at Te Marua have caused minor operational problems. It will be necessary to closely investigate problems associated with the concept of lake management prior to next spring. 2. Water Quality A total of 321 samples from trunk mains were tested for coliform organisms. None of these samples tested positive. Secchi disc water clarity in the Te Marua north lake varied between 2.9 m and 3.5 m, and in the south lake between 5.6 and 7.8 m. These are considered satisfactory. The dominant phytoplankton were as follows: ! North Lake: Oscillatoria, Synedra, Ankistrodesmus ! South Lake: Chlroella, Staurastrum, and Cyclotella Oscillatoria is a filter clogging algae when present in high concentrations. Synedra produces a musty smell and slick tongue sensation when abundant. Chorella produces a musty smell and Staurastrum a grassy smell when abundant and Cyclotella is responsible for a fishy odour with geranium under tones. Dissolved oxygen and pH readings are also satisfactory. Giardia and Cryptosporidium results were as follows: Te Marua Lakes ) No Giardia )No Cryptosporidium Intake ) No Giardia )No Cryptosporidium Attachment 1 to Report No. 99.728 Page 4 of 38 Treated Water ) No Giardia )No Cryptosporidium Wainuiomata Treated Water ) No Giardia )No Cryptosporidium Lower George Creek ) No Giardia ) Low Cryptosporidium Big Huia Intake ) Low Giardia )No Cryptosporidium Intake ) Low Giardia ) Low Cryptosporidium George Creek South arm ) Low Giardia ) Low Cryptosporidium Orongorongo Intake ) Low Giardia ) Low Cryptosporidium During October 12 transgressions were notified: ! 1 high fluoride ! 4 low fluoride ! 4 low chlorine ! 1 high pH ! 1 presumptive coliform Five artesian samples were tested for the presence of macro-organisms this month. None were detected. This testing is necessary to prove security of the groundwater. 3. Supply Situation The two monthly seasonal forecast for October and November 1999 issued by the Meteorological Service is as follows: Attachment 1 to Report No. 99.728 Page 5 of 38 Situation as at 10 August: For Wellington: Rain: 90 to 100 percent normal. Wind: Slighter less than normal. Temperature: Continuing about 1 degree above normal. Sunshine: Average Specials: Stretches of dry weather lasting several days. Confidence: Moderate to high. Spring showers this year are below par. We expect that some of the northwest gales may be severe, as occurs every spring but there should be fewer such events this year. Cold snaps are likely to be brief and rather weak but some of them could bring thundery showers. Hutt River Flows The mean monthly river flow for month of October was below average. 30000 1998/99 Min (1968 - 1998) Mean (1968 - 1998) 25000 Max (1968 - 1998) 20000 15000 Flow (L/s) 10000 5000 0 Nov Dec Jan Feb Mar Apr May June July Aug Sep Oct Month Wainuiomata River Flows Attachment 1 to Report No. 99.728 Page 6 of 38 The river flows for the month of October was below average. 4000 1998/99 Min (1982 - 1998) 3500 Mean (1982 - 1998) Max (1982 - 1998) 3000 2500 2000 Flow (L/s) 1500 1000 500 0 Nov Dec Jan Feb Mar Apr May June July Aug Sep Oct Month Aquifer Levels The aquifer level for October was just above normal. 5000 4500 4000 3500 3000 Le vel (m m) 2500 2000 1500 1000 1998/99 Min (1971 - 1998) 500 Mean (1971 - 1998) Max (1971 - 1998) 0 Nov Dec Jan Feb Mar Apr May June July Aug Sep Oct Month Attachment 1 to Report No. 99.728 Page 7 of 38 4. Production 4.1 Wainuiomata 4.1.1 Quality As a result of the plant optimisation trials, the treated water quality has been improved. 4.1.2 Safety One cut finger. No time lost. The implementation of the health and safety procedures is proceeding slowly. 4.1.3 Operations During the month a number of items of equipment failed. These were mainly instruments, which have been replaced. Problems have been experienced with the quality of lime received from our suppliers. It appears that there is a higher level of sand in the lime than should be present. Consultations have occurred with our suppliers who have assured us that they can resolve the situation. During the storms at the end of October the 11,000 volt power lines fell onto the telephone circuits. The PABX, autodialler and a modem were damaged. What followed was an extremely peaceful and productive interlude before the telephone system was repaired. Plant Tours 1 October: Wellington Regional Council arranged “water tour” 30 people 13 October: 15 “B” certificate water treatment students. 4.1.4 General As part of the online plant trials, the coagulant was changed to a PAC. The results were so dramatic that this has become a permanent situation. The plant is now producing water that has a turbidity level below that detectable by the on-line instruments. Since being on PAC, higher than normal flows have been able to be maintained. On Friday, 12 November, the first high river event occurred since being on PAC. One hundred and thirty true colour and 32 turbidities were treated, with a finished water quality of 0.1 NTU. Attachment 1 to Report No. 99.728 Page 8 of 38 Although it was not cost effective to do this, it is reassuring to know that it can be done and provided verification of the effectiveness of the optimisation trials. Minor equipment and instrument failures continue to hamper the operation of the treatment plant and the staff, contractors and consultants believe that there is a boredom subroutine in the software. If the place is running smoothly, it decides to make some part of the process fail. However, the same thing never occurs twice. 4.1.5 Projects Capital Works ? The strengthening of the Wainuiomata Bridge has been completed. Operational Projects ? The replacement of the coagulant storage tank is in progress. 4.2 Waterloo Water Treatment Plant 4.2.1 Quality As stated previously, concern has been expressed as to the quality of lime supplied. This has possibly contributed to fluctuating turbidity levels in the treated water. This problem has now been rectified. 4.2.2 Safety There are no accidents or incidents to report. 4.2.3 Operations 31 October: Wellington No. 1 variable speed drive failed with a lot of enthusiasm. The previous failures have had logical explanations and solutions have been implemented. 11 November: Naenae No. 2 motor terminals flashed over. We think this is because of a contractor not tightening the terminals properly. The motor contactor welded, closed during this fault, and needs to be replaced. Plant Tours 1 October: Wellington Regional Council arranged “water tour” 30 people Attachment 1 to Report No. 99.728 Page 9 of 38 4.2.4 General With the lake filling at Te Marua, Waterloo is supplying the bulk of the water. The aquifer levels are still healthy and the plant is running reliably. 4.2.5 Projects Operational Projects ! Aerator A mixer refurbishment. ! Lime waste disposal. ! Labelling of assets for asset management system. 4.3 Gear Island 4.3.1 Quality No quality issues to report. 4.3.2 Safety There are no accidents or incidents to report. 4.3.3 Operations 11 October: The plant was turned off to replace the main switchboard and drives. 15 November: The fixed speed pump and one DC drive has been commissioned. There are still some issues to sort out with the other DC drive. Full plant flow can still be achieved. 15 November: The caustic dosing pump stroke positioners were commissioned. Plant Tours 1 October: Wellington Regional Council arranged “water tour” 30 people 4.3.4 General For the first time in years there has been a period of time when Gear Island has not been used. It was noticed that the sample taken from one of the well pumps was discoloured. It took a day and a half of flushing before the well pumps came clear. Gear Island will continue to be operated periodically in order to keep the well pumps flushed. Attachment 1 to Report No. 99.728 Page 10 of 38 4.3.5 Operational Projects ? Switchboard replacement. ! Labelling of assets for asset management system. ! The Buick Street plant was removed from service on 8 October. 4.4 Te Marua 4.4.1 Quality Increased aluminium levels have been identified because of problems with direct filtration. 4.4.2 Safety There are no health and safety issues to report. 4.4.3 Operations Disruption to plant power because of a vehicle colliding with a power pole on State Highway 2 south of the Te Marua plant. 4.4.4 General Te Marua Generator Work is progressing well on the installation of the new generator at the Te Marua Pumping Station. Kaitoke Generator Corrosion within the electronic controls of the Kaitoke generator has required new equipment to be installed. This work is due to be completed early in November. Lake Quality An algae bloom has been detected in Lake 1. Because of the type of algae involved (potentially toxic), an increased programme of monitoring has been implemented.