CASE STUDIES IN INNOVATION: Pre-Engineered Pump System Effectively Doses Sodium Bisulfite in Water Treatment Process
seepex’s Pre-Engineered Chemical Metering Skid Systems support a wide variety of liquid chemical dosing applications, primarily for disinfection in water and wastewater treatment facilities. They are designed to eliminate the valuable time and costs associated with engineering, procuring, assembling, and commissioning flow control systems. A customizable system is packaged into a single unit with all the components necessary for chemical dosing and with (or without) controls and framework. The skids can deliver mild-to-aggressive, thin-to-highly viscous liquids, as well as corrosive and solid-laden chemicals.
In various water treatment plants in Puerto Rico, a total of eight skid systems are installed and utilized for handling sodium bisulfite in water filtration processes. The sodium bisulfite controls the chloride levels of the effluent water. The skids were commissioned at seepex’s manufacturing facility in Enon, Ohio, according to each application’s flow ranges and then calibrated according to the flow control loop. Each skid consists of two seepex progressive-cavity MD 003-12 pumps, each with a motor and VFD, a Pressure Control Mechanism (one gauge, one relief valve, and one bypass valve), a calibration column, along with piping and accessories. The systems are indoors, and the pumps operate continuously eight hours a day.
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Luiz Rodriquez, a contractor with Electrical Instrumentation Contractors, Inc. (EIC, Inc.), who helped select and install the seepex skids at the water treatment plants says, “The end users and I are very satisfied with how easily the skids integrated into the existing operations, like a plug-in and play installation. The skids work great and perfectly fit our needs of simple integration and ease of installation. We have had only positive feedback from the end users.”
With chemical-resistant materials, all skid components will hold up in harsh acidic and caustic chemical environments. Components include calibration column, pressure gauge, pressure switches, dry-run protection, and flowmeters. Also included are superior-quality seepex progressive cavity pumps. Components of the pumps, such as elastomers, exotic metals, and plastics are also custom designed with chemically resistant materials. An integrated vector drive with automatic (4-20mA) or manual digital speed control comes standard, eliminating the need for a local interface/control panel.
The systems handle pressure up to 350 PSI, flowrates from 10mL/min to 100 GPH, and have turndown capability of 60-to-1. With Non-pulsating flow, accurate and reliable metering is assured. Progressive cavity pumps do not have ball valves, therefore they are not prone to vapor lock and do not require back pressure valves or priming chambers. This makes them a good fit for pumping chemical solutions with high vapor pressures like sodium hypochlorite or ammonia.
