The filtration vessels are at the heart of the reverse osmosis water treatment process. For every four gallons of brackish water treated, three gallons of usable water is produced. USING REVERSE OSMOSIS TO MAIm IRRIGATION WATER The reverse osmosis water treatment process can turn brackish water into a valuable resource for golf courses. by GLEN A. MILLER ATER is perhaps the most osmosis (or "RO") water treatment tions to achieve the same concentra- precious resource for any process. tion. To do this, water from the fresh W golf course, and a reliable, side would pass to the salty side and economical supply of good quality irri- What is Reverse Osmosis? this would continue until they reached gation water should be a priority for To understand reverse osmosis, one an equilibrium. At the end, the water every course. What is the water situ- must first understand osmosis. Osmosis level on the original salty side will be ation at your course? Are you buying is a naturally occurring phenomenon higher (and now less salty), and this your irrigation water, and is the cost of that is all around us. The cells in your water height difference is called the water becoming a real budget issue? body get water via osmosis. Osmosis is osmotic pressure. Do you have to curtail watering due to the process by which water passes from If we put some pressure on the salty water restrictions? Are you located in a dilute (or fresh) solution to a more side, it will slow down or prevent an area where there is not sufficient concentrated solution across a semi- osmosis from occurring. Ifwe put more fresh water to supply your irrigation permeable membrane. The membrane pressure on the salty side, we will not needs? is a barrier that allows the passage of only prevent osmosis, but we will cause Even if you are surrounded on all water molecules, but not the passage of water to flow in the other direction, and sides by brackish or salt water, there is dissolved solids in the water. this is called reverse osmosis. an option available that can provide Let's say there are two containers, The reverse osmosis water treatment plenty of fresh irrigation water and one with fresh water and the second process applies enough pressure to a save money. For golf courses in coastal with salty water filled to the same level salty water supply to make pure water areas or other areas with only brackish and connected to the first container flow through a membrane. The saltier water available, this water can be by a semi-permeable membrane. The the supply water, the higher the pres- effectively purified using the reverse natural tendency is for the two solu- sure needed to produce the water. All NOVEMBERIDECEMBER 1998 5 reverse osmosis process systems have pump humming away on the RO wanted to save money on water, which some degree of pre-treatment needed to system. Operators do not need to be was getting expensive, but we also condition the water to minimize plug- present during plant operation, and wanted to control our water supply and ging or fouling of the membranes. Most they only need to make periodic checks protect our investment." membrane elements today can remove to monitor the system. In fact, to save Miller Engineering evaluated the up to 99.5 percent of the salt from the on power, which is the single largest situation and recommended the most water. operating cost, the system was designed cost-effective solution. In this case, In this article, we will look at two to operate at night to take advantage there was no shallow brackish ground- golf courses that have built treatment of lower, off-peak power rates from the water, but there was brackish ground- systems and now make their irrigation electric utility. water 1,500 feet down. A deep well was water. We also will discuss how you can Peter Brooks has been operating the constructed to supply the' brackish evaluate whether this option is right system for more than two years. Using groundwater to a new 200,000-gallon- for your course. 100 percent treated water on the golf per-day RO treatment plant (expand- course, operating costs to produce able to 400,000 gpd). The well was The Everglades Club: Making water are now averaging about 40<!:to under pressure ("artesian"), which Water and Saving 75 Percent 45<!:per 1,000 gallons. This cost com- meant that a pump did not have to be Located on the Barrier Island of pares to $3.18 per 1,000 gallons for placed down the well. To save payroll Palm Beach on the lower southeast potable water. With the RO system costs, the plant was designed to operate coast of Florida, a beautiful golf course producing fresh irrigation water, the 24 hours per day and limited computer- has been maintained at the Everglades club is saving more than 75 percent of ized operations were incorporated. Club since the early 1920s. Surrounded the cost previously paid to purchase The plant has been in operation by the Atlantic Ocean and the Intra- water from the town. The expected since April 1998. The treatment build- coastal Waterway, the course has no payback for the irrigation water treat- ing was designed to be unobtrusive and fresh water and has to purchase potable ment system is about five years. is located directly on the golf course. water to irrigate the course. With the Jim St. John, managing director, notes, Jupiter Island Club: "Putting the building in the middle of cost of water rising and no end in Going Deep for Savings sight, the club wanted to do something the course, next to the irrigation lake, to lower its water bills. In addition, Located about 20 miles north of made a lot of sense. We had to make the club recognized that it was using Palm Beach, the Jupiter Island Club sure we could hide it from view, which pristine drinking water for irrigation, was faced with similar, but more severe was not a problem." Operating costs to and for environmental reasons wanted water problems. While they have a produce water are comparable to the to help preserve the limited fresh large freshwater reservoir for storage Everglades Club, and the savings are groundwater. Peter Brooks, golf course of irrigation water, the only source for substantial. Moreover, the club now superintendent for the Everglades the fresh water is limited stormwater has control over the supply and quality Club, was placed in charge of finding runoff and a water pipe from the local of its irrigation water. a solution. Brooks said, "Our water water utility located on the other side bills were going through the roof. We of the Intracoastal Waterway. Not only were water rates going up, but availa- Is Reverse Osmosis knew we had to do something. When Right for Your Course? water restrictions came out, we knew bility of water also was an issue. Rob the time to act was now." I<loska, golf course superintendent, As cited above, you do not have to Miller Engineering was brought in to recalls, "We were starting to see days be a water treatment utility with experi- evaluate the situation and recommend when the utility company shut us down enced operators to consider using a solution. The solution was for the during drought conditions when we reverse osmosis treatment to produce club to start making its own water. needed water the most. With more than irrigation water. Most systems operate Although there was no fresh water 100 acres of golf course and landscape automatically so that constant atten- around, there was plenty of salt or to irrigate, water is critical. We have a tion and maintenance are not required. brackish water. Miller Engineering lot invested in plant material. We However, several issues are important designed a water plant that would use the reverse osmosis treatment process to remove the salt from the brackish groundwater and produce water fresher than they were currently buying. The treatment plant was designed to produce 600,000 gallons of fresh water per day. On-site shallow wells were installed to supply brackish ground- A 1,500-foot- water to the plant. For every four deep artesian gallons of brackish well water, the well supplies plant produces three gallons of fresh brackish water. The treatment system is com- water to the puter controlled and is designed to reverse osmosis plant operate automatically. All of the equip- at the Jupiter ment is housed in a building con- Island Club structed on the eastern edge of the (Jupiter, property. The only noise is the feed Florida). 6 USGA GREEN SECTION RECORD expenses include electricity, treatment chemicals, prefilter cartridges, and periodic cleaning chemicals. Normally, additional staff is not added strictly for the plant, so labor is not an oper- ating expense. Operating expenses for brackish water systems will run 30<1:to 50<1:per 1,000 gallons produced. Elec- tricity for a brackish plant will be about 50 percent of the total operating cost. Another recurring expense is replacement of the membrane elements in the treatment system. Elements cost about $500 to $700 each and are guaranteed for three years, but most installations can and do achieve ele- ment lives of more than 10 years. Set- ting aside funds for 6-year membrane replacement life will add about 8<1:per 1,000 gallons. "l A payback analysis is normally per- Peter Brooks, CGCS, is at the computer controls of the reverse osmosis plant at the formed to estimate how long it will take Everglades Club on the Island of Palm Beach (Florida).