DRINKING WATER TREATMENT PLANT
In May the Water Treatment Plant sent out approximately 10,500 educational water quality reports to all consumers in North Andover. The purpose of these brochures is to keep the public informed and educated about such subjects as the water treatment process, analytical test results, such as lead in drinking water, lake protection, water conservation, and contamination from cross-connections. Educational tours were given throughout the year to school age children, plus guest speakers from the water department visited a few
This year the lake did not need to be treated for an algal bloom. The levels of algae are carefully watched, especially in the summer, as this can cause problems with treatment and filtration, which, in turn, can increase the cost of cleaning the drinking water. The reduction in the use of fertilizers in the watershed has helped decrease nutrients which feed the algae thus keeping the lake clearer.
This year all Water Treatment Personnel were retrained in Lock Out/Tag Out so that they safely are able to protect themselves and other when working with equipment for maintenance and repairs. This is just one example of on-going training that all water treatment personnel go through each year to keep them up to date of the latest methods for safety or technology in the water treatment field. All operators also fulfilled all required educational requirements needed to maintain their licenses in the water treatment field.
Throughout this fiscal year many repairs and improvements were made within the DWTP, Booster Pump Stations (BPS) and Storage Tanks. The DWTP machinery, piping and equipment, now 20 years old, are showing signs of age, which demands greater attention and maintenance. This includes repairing and replacing aged chemical feed pumps and other samples pumps throughout the treatment plant.
Improvements were made to Foxwoods Booster Pump Station to help increase pressure and provide adequate fire protection for that area. This improvement included new pumps and control systems to upgrade the aging equipment that was there.
Work has begun at the Bear Hill storage tank to install a Booster Pump Station to help with water pressure and maintain adequate fire protection for the surrounding neighborhoods. This project is scheduled to be completed by this spring.
During 2010, one of the ozone generators was shutdown for preventative maintenance. Several of the glass electrodes, which form ozone gas under pressure and high voltage, were found to be not functioning properly and thus replaced. A power monitor was installed and connected to the control PC to record incoming electrical activity and power surges.
In the lab at the treatment plant, a new inline fluoride analyzer was installed so that the level of fluoride is continuously monitored in the water being pumped into the distribution system. This monitoring is helpful in that is allows water treatment personnel to quickly see if the fluoride amounts are too low or two high. The data is recorded every 4.2 minutes and plotted on a graph or “trend” so that it can be looked at and compared with other treatment processes to optimize the performance of the treatment plant and produce the best quality water possible.
In the fall, divers were brought in to inspect the hatch where water is released from the lake as well as the intake structure. Both structures were found to be in excellent shape and did not require any repair.
Plans were also set to upgrade two turbidimeters on two if the eight carbon filters in the treatment plant. The two existing turbidimeters are older models and will now match the other existing equipment in the rest of the plant. These meters are used to measure the amount of particles floating in the water, or the clarity. A second free chlorine analyzer is also planned to be installed to monitor and record the level of free chlorine in the clear well at the treatment plant. The clear well is where the water mixes with the chlorine. The length of time the water spends in the clear well is called the “contact time”, this is the time needed for the chlorine to adequately disinfect the water before it is pumped to residents and storage tanks. This equipment will assist in monitoring the
demand of chlorine needed based on the quality of water being treated.