Hach Helps Customers Meet Strict Quality Guidelines

Quenching your thirst with cool, clear water is a very refreshing experience. However, you want to be certain that the water is not contaminated or polluted in any way. Impurities in drinking water can be a source for both disease and pollution. Effective process monitoring is important to ensure that water treatment systems have removed these impurities or reduced them to safe levels.

Automated Monitoring Solution Promotes Higher Water Quality

Founded in 1947, the Hach Company is the premier source of systems for water quality analysis. The company manufactures and supplies laboratory and process instruments, portable laboratories, test kits, and analytical chemicals for testing and analyzing various water sources. A common water analysis technique focuses on turbidity, which is an excellent indicator of the overall quality of liquid process streams. In the past, water treatment and water waste plants would typically send technicians to physically collect samples in glass vials. The samples would then be transported to a laboratory, where specialized instruments would measure water quality and take readings of the contamination level. This process, which required considerable time and labor, was costly and fairly unreliable.

“Water treatment plants can save up to 30 percent of their instrument installation cost, and 50 percent of their cabling costs”

According to Ken Stutzman, software systems manager, “Different technicians had different sampling techniques, which often yielded inconsistent results. In addition, the time that elapsed between obtaining and analyzing the samples ranged from five minutes to one hour. This often contributed to sample degradation.” External contaminants were often inadvertently introduced during the transfer of the sample from the vial to a laboratory instrument. Furthermore, the laboratory results only showed water conditions at the time of the sampling and could not detect a trend in the turbidity level.

“We realized that an automated, continuous monitoring solution offered substantially greater efficiency and accuracy than the manual method,” says Stutzman. The first generation of turbidity instruments developed by Hach Company were standalone units that used 4-20 mA current loops and chart recorders for data gathering. Interfacing these instruments to computers proved to be both challenging and expensive.

To remedy the situation, Hach Company devised a series of goals for the new distributed instrument system. “We were interested in significantly reducing the costs associated with interfacing to the older instruments,” comments Stutzman. “We also wanted the ability to quickly accommodate evolving governmental regulations relating to water quality.”

Neuron Chip Captures Critical Data on Water Contaminants

After evaluating different vendors, Hach Company selected Echelon’s control networks platform. “Echelon was the only vendor with a complete set of development tools,” states Stutzman. “We were also impressed with the functionality provided by the Neuron Chip.” The Neuron Chip’s multiprocessors saved Hach from the cost and development effort required to place additional processors on the sensors.

The LonWorks architecture supports a distributed network of filters placed throughout water treatment and waste water plants. In a typical configuration, Hach Company’s 1720D Turbidimeter sensors are placed on the influent (to measure the clarity of water sources), the effluent (to measure clarity of treated water), and at intermediate locations (to measure the effectiveness of each water filter). Neuron Chips embedded within the sensors capture information on contaminants and transmit the data via FTT-10A free topology twisted-pair transceivers to Hach Company’s AquaTrend Interface module. This module provides data logging and graphical display for up to eight sensors.

Satisfying Taste Buds at St. Charles Parish Waterworks

St. Charles Parish Waterworks in Louisiana is one of Hach Company’s satisfied customers. With two plants located on both sides of the Mississippi River, the facility supplies water to approximately 40,000 people. St. Charles Parish Waterworks uses the LonWorks-based system to track filter runs, monitor filter breakdowns, and obtain more efficient back-washing procedures. According to Tom Keller, plant technician, “We use the distributed control network as a total monitoring tool to streamline and enhance our water treatment procedures.” At the St. Charles facility, 32 Turbidi-meters are split between the two plants, with three AquaTrends located in the control room of each plant. A serial module provides an RS232 link between the LonWorks network and the host computer. “We draw our water from rivers, lakes, and reservoirs,” explains Keller. “Clarifiers are used to remove 90 percent of the contaminants from the water coming into the plant.” Turbidimeters attached to the facility’s 15 filters take daily readings of water turbidity. The sensors are also located on two lines leading out of the plants to ensure that the treated water meets regulatory guidelines prior to being pumped to homes and businesses. “We now consistently come out on top in our periodic water taste tests!” boasts Keller.

Hach Customer Lowers Treatment Costs While Improving Water Quality

The St. Charles Parish Waterworks is a prime example of the benefits of using a LonWorks-based system. “The solution is extremely efficient,” emphasizes Keller. “We cut our water treatment costs while ensuring very high water quality.” He cites as an example the ability to eliminate physical sampling with its inconsistent and unreliable results. In addition, the continuous, on-line monitoring of the water treatment processes provides critical real-time information. “We know instantaneously if a reading is too high or too low,” states Keller. “The immediate feedback lets us quickly adjust for out-of-range conditions.” The fast detection and correction of abnormalities also allows St. Charles to comply with regulatory statutes, thereby avoiding fines and penalties associated with hazardous waste problems. Keller adds that the facility meets stricter water quality standards recently issued by the Department of Health and Hospitals.

Stutzman cites some of the additional cost savings that can be achieved from using the LonWorks-based solution. “Water treatment plants can save up to 30 percent of their instrument installation cost and 50 percent of the cabling costs using a 1720D/AquaTrend system versus a non-LonWorks system.” Higher quality water and a lower drain on expenses—both are possible due to LonWorks control networks.

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