Jan 31 17 9:52 AM

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High cost of water in ethanol.

Ethanol Producer Magazine

By Susanne Retka Schill | January 24, 2017

Plants use lake water or cooling pond water from a power plant, or from shallow wells, deep water wells and grey water from municipal water treatment. “


“ The drive to reduce water use is motivated by three pressures, he suggests: regulatory, economic and societal. Water cost and, in some cases, scarcity, have plants looking at new water sources, plus the plants that discharge—still the vast majority of the industry—are finding that in each permitting cycle, the limits get tighter and the number of constituents to track increases. “Regulations are targeting constituents such as sulfates, total dissolved solids, phosphate, selenium, chloride, nitrogen, ammonia and others.  In addition to the constituents being regulated, discharge limitations vary from state to state, and even from plant to plant, depending on the conditions of the stream or watershed receiving the discharge,” he says. “


“The cooling tower, for instance, is the biggest direct user of water in an ethanol plant, with the majority of the water being evaporated, leaving a concentration of minerals and solids. “


If continuous improvement has been the story for water treatment the past two decades, what’s in store ahead? Meyer suggests that regulations pertaining to phosphates and sulfur compounds are going to continue to receive attention in the near term. Poet’s Anderson says more efficient cooling towers would be an exciting development. Further water recycling may be possible in the future, as well, he suggests. As plants develop ways to capture more energy, the benefits include more condensates that can become part of recycled water flows.