Understanding and evaluating "non-contact" cooling water is crucial to the successful siting of any ethanol plant. The constituents in "raw water" influence the quantity and quality of the discharge, capital equipment requirements and ongoing operating expense. Thus the evaluation of the "raw water source" should be taken seriously and treated in a scientific manner. The differences in water quality can dramatically affect the feasibility of a project.
 	
 The following examples are taken from three projects. Each project presented its own set of unique challenges. In these examples, the sites were eventually discarded due to water related issues. 
 	
 When evaluating raw water, the entire makeup of the water must be evaluated. Very rarely is there a single element in a water source that renders it unusable. The following examples are real analyses processed during site selection work U.S. Water Services participated in. All raw water analysis are listed as CaCO3 equivalents. 
 
 
 Site1
 This site would appear to have very good water quality. Low conductivity, iron, sulfates, nitrates and hardness. 
 

 This water source did not create a problem within the plant in terms of managing scale and corrosion in the cooling tower. However, it created problems when discharged. When this water is concentrated in the cooling tower and then discharged, the conductivity would exceed 1,800 umhos. The point selected to discharge the water had a state mandated limit of 1,000 umhos. In order to discharge the water and keep the concentration below 1,000 umhos, the total volume of water required for operating the cooling tower would have increased four-fold. 
 	
 If the water in the tower can not be "cycled up" during normal operations, the only other option is to increase the amount of water through reduced cycles of concentration. The state would not permit the project to draw that much water from the aquifer even if the well would have supported the increased demand.
 	
 Additionally, the chemical cost for treating the increased volume of water added substantially to the operating expense of the plant. Selecting and building an ethanol plant on this site would have contributed to an additional capital expense in excess of $500,000 for running discharge piping to a receiving source with enough flow to sufficiently dilute the discharge to stay within the mandated conductivity limits. The ongoing operating expense would have added $125,000 per year as well. 
 
 
 Site2
 This water supply has five negative aspects to it: High conductivity, high total and calcium hardness, high sulfates and borderline soluble iron. 
 	
 The discharge of this water to the receiving source was not the issue. The receiving stream had sufficient flow to dilute the conductivity limit the state had set but the combination of high sulfates and high hardness created issues with scale and corrosion protection in the cooling tower and "RO system." In order to supply the plant with the necessary quality of water, the majority of the water would have to be processed either through a "multimedia filter" or an RO system, in order to remove some of the negative elements. 
 	
 The final evaluation required an RO eight times the original size estimate. The additional capital required was in excess of $400,000. There was actually a decrease in operating chemical expense because the high quality RO water would be used in the tower, but the payback for the reduced chemical could not justify the upfront capital. 
 
 
 Site3

 This water source had high conductivity, and in this case, that one aspect was enough to create problems. 
 	
 The state mandated a discharge limitation of 2,000 umhos. The plant did not have the luxury of sending their discharge to a flowing stream to gain the benefit of dilution. In this case, the plant would have been in violation of state discharge limits if they did nothing more than pump the water out of the well and discharge it on the ground. In order to utilize this source of water, the project would have had to build a municipal style waste water treatment facility. The up front capital would have added millions to the project cost as well as hundreds of thousands of dollars to the annual operating expense of the plant. 
 
 
 Conclusion
 In all three of these cases, the water created significant enough issues that the site was not chosen. Water is only one aspect of the site selection process but it can add significant cost to the long-term operating cost of the plant. That information needs to be included in the site selection process or the consequences can be adverse.
 	
 For more information about site selection criteria as it pertains to non-contact water discharge, contact<a href="mailto: Mlocascio@uswaterservices.com"> Mlocascio@uswaterservices.com</a>. EP

The Cost of Bad Water

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The Cost of Bad Water.css-7jxktu{position:absolute;bottom:0px;left:0px;right:0px;height:3px;border-radius:3px;background-color:var(--chakra-colors-brandBlack);}

Upcoming Events

2024 International Fuel Ethanol Workshop & Expo

Biodiesel Summit: Sustainable Aviation Fuel & Renewable Diesel

Carbon Capture & Storage Summit

North American SAF Conference & Expo

2025 International Biomass Conference & Expo

The Cost of Bad Water