• HWM Equipment Protects Water Supplies in Mogi Mirim, Brazil

    September 2012


    Mogi Mirim, a municipality in the state of São Paulo in Brazil has recently invested more than $7 million in sanitation and water resources. This includes purchasing equipment to improve the city’s water and sewage system in order to improve the level of service provided to the population. With funding from the municipality, SAAE has purchased a range of vehicles and equipment to improve the water network.

    Recent purchases include sophisticated acoustic technology from HWM to identify leaks on underground water pipes and then pinpoint their location. Permalog+ is the world’s most popular leak noise logger, with hundreds of thousands deployed on water networks throughout the world. The small battery powered devices listen to noises travelling through pipes and can recognise the distinct sound that water makes when it escapes under pressure. They are used to alert the operator to the presence of leaks, even when there is no outward sign of leakage above the ground. When a leak area is identified, the MicroCorr Touch leak noise correlator is used to pinpoint its precise location down to a few centimetres.

    The correlator works by measuring the time difference at which leak noise is received by sensors deployed at either side of the suspected leak. Leak noise travels at a constant velocity, which depends on the material and diameter of the pipe. As a result, the time difference between the arrival time of the leak noise at each sensor, combined with the velocity, enables the exact position of the leak to be quickly and accurately calculated. Whilst the principle of correlation has remained unchanged since HWM developed the world’s first correlator over thirty years ago, the technology behind it has advanced considerably.

    In addition to using highly sensitive accelerometers on the pipes, the MicroCorr Touch features a high visibility colour touch screen and intuitive menu driven software to make it easy to enter data and view results. The system also incorporates a unique automated filtering intelligence system (AFIS) to automatically run 55 different filter combinations on the data until the clearest and most accurate result can be displayed.

    Tests have shown that AFIS significantly improves leak pinpointing on a wide range of different pipe materials and sizes; making it arguably the easiest to use and most accurate correlator the company has ever produced. It is very time consuming, expensive and disruptive for a water company to excavate a section of buried water pipe only to discover that the leak is somewhere else.

    Therefore, as a final check that the leak has been successfully identified, SAAE use HWM’s Xmic electronic ground microphone to amplify the leak noise and so confirm the location of the leak before digging down to make the necessary repairs. Using the latest acoustic amplification technology, Xmic displays results graphically on a hand held screen to confirm the leak position. This significantly reduces the number of “dry holes” that are dug before the leak can be repaired. Pauloroberto Silva Jnr who leads the technical division of water distribution management for SAAE recognises the improvement that HWM’s groundbreaking leak detection equipment has already made to the municipality’s water supplies.

    “Following our investment in water loss equipment, the Permalog+ leak noise sensors and MicroCorr Touch correlators have already enabled the SAAE to find more than 100 invisible leaks. Water losses have fallen from 44.3% to 38.7%”, he said. SAAE are also enjoying other substantial cost savings as a result of introducing such an effective leak detection programme. Previously, the municipality had to operate its water treatment plant for twenty-three hours a day to meet demand.

    After successfully identifying and repairing so many leaks Silva Jnr reports that they are now able to reduce this operation by three hours each day, which has brought their electricity consumption down by more than 10%. This means that purchasing the equipment has already produced an excellent return on investment and helped Mogi Mirim reduce their carbon footprint. SAAE have also installed 15 Pressure Reducing Valves (PRV’s) in various parts of the city and purchased new pipes and fittings to reduce the frequency of maintenance required on the network.

    They will shortly be constructing a new water storage facility to meet the increased demand for water throughout Mogi Mirim. Also planned is a collector sewer stream in nearby Bela Vista which will connect to the existing sewage treatment plant. Land bordering the water treatment facility has also been purchased which will enable its future expansion and double the current capacity.

    According to Evandro Trentin, the administrative and financial director of SAAE who manages the water and sewage infrastructure at Mogi Mirim, these investments are justified because they will improve the quality of life for everyone living in the area. "Our sanitation and water resources need a great deal of attention and we are determined to improve them. Over the coming years, the investments we’ve made will ensure that we can meet the increasing demand for water in the region”.