AWWA MTC64585

In 1994, the Carmel Area Wastewater District, Pebble Beach Community Services District, Monterey Peninsula Water Management District, and Pebble Beach Company formed a public/private joint venture to produce and deliver recycled water for irrigation to seven golf courses in Pebble Beach, California, including world-renowned Pebble Beach Golf Course. Through this venture they began the Water Reclamation Project, including tertiary treatment by sand filtration followed by chlorine disinfection. Shortly after start of operation of the new tertiary facilities, the Pebble Beach golf courses began experiencing some problems with the turf grass, particularly on the greens. This was discovered to primarily be the result of high sodium concentrations (at times as high as 200 mg/L) and high total dissolved solids (TDS) concentrations (at times as high as 1000 mg/L). To remedy the problem, the consortium, along with golf course superintendents, turf grass specialists, and Carollo Engineers, began the Salinity Management Project with the intent of improving the water quality and increasing the quantity of recycled water available for irrigation. As a result of early discussions, the turf grass water quality criteria included a maximum sodium concentration of 55 mg/L, maximum Sodium Adsorption Ratio (SAR) of 3.0, maximum adjusted SAR of 4.0, electro-conductivity range of 350 to 450 micro-mhos/cm [corresponding TDS range of approximately 225 to 290 mg/L], and pH range of 6.3 to 7.3. Microfiltration (MF) followed by reverse osmosis (RO) was selected to meet this water quality criteria. MF will also allow the treatment facilities to continue to meet the California Title 22 requirements for unrestricted use of recycled water. Several chemical feed systems, such as calcium hydroxide and gypsum, are also included to help meet the turf grass water quality criteria and to help stabilize the corrosive RO permeate. Includes tables, figures.