Ixom Watercare’s Water Selector™ (patent pending) is a key part of effective raw water treatment and an integral component of a comprehensive reservoir management program. By continuously monitoring reservoir water quality over the entire depth profile and allowing your operators to choose the raw water they want to treat, Water Selector will provide for chemical cost savings, reduce risk of negative treatment outcomes, and improve treatment plant and reservoir management capital improvement planning.
Ixom Watercare is finalizing plans for a full-scale trial at a southeast raw water reservoir in fall 2017. The city’s water treatment plant (WTP) draws raw water from a nearby lake, a relatively large man-made reservoir primarily sourced from surface waters downstream of a major metropolitan area. The lake is influenced by nutrient loading, significant recreational use and runoff. Low flow conditions have a significant impact to lake water quality, which directly affects the water treatment plant raw water condition and system performance.
The existing primary intake structure used to harvest raw water for treatment contains four intake gates at fixed elevations. The WTP experiences problematic iron and manganese in its raw water. During the warmer months, planktonic algae is seen growing, observed from the water’s surface as a greenish tint, which leads to taste and odor issues. The plant doses sodium permanganate and chlorine dioxide to oxidize iron and manganese to improve conventional treatment floc/sedimentation/filtration. Powdered activated carbon (PAC) and sodium hypochlorite are dosed to reduce taste and odor (T&O).
The Intake Water Selector (IWS) is a reservoir management and raw water pretreatment tool designed to enable operators, in real time, to understand and control the water quality drawn into the treatment plant influent. The Selector offers the ability to allow a thin profile of preferred water to enter the water quality barrier. Within this zone, only preferred water exists and therefore only preferred water is permitted to enter the fixed gates of the intake regardless of which intake gate is open.
In the trial case, the epilimnion (upper stratified layer within the reservoir) exhibits high levels of T&O and turbidity associated with algae. One or more of the Water Selector gates will be opened that is below the well-mixed upper layer but above the oxygen-poor lower depths. The selected water will be harvested using a lower fixed intake gate whereby only preferred water with lower T&O and yet also minimized iron, manganese, hydrogen sulfide and organics is permitted into the WTP. This makes treatment easier and less costly with reduced chemical demand and with reduced risk of unacceptable treated water to the customer.
While a considered reservoir management program is important, the cost and practicality of effective implementation of whole-basin corrective actions can be prohibitive. This is where Water Selector has significant value. It allows understanding of the environment local to the intake structure, selection of preferred water quality and pretreatment in-reservoir prior to harvesting via the intake.
Ixom Watercare is exhibiting at WEFTEC.17, Booth 7751. For more information, visit ixom.com.