To meet the low phosphorus limit (0.1 mg/l) for the Tualatin River, our Rock Creek and Durham facilities both participate in a unique partnership with Ostara Nutrient Recovery Technologies. Ostara has developed a technology for directly removing phosphorus and ammonia from wastewater that would otherwise have to be retreated. This proprietary technology, called the PEARL™ process, diverts the phosphorus and ammonia to a reactor that converts them into a premium, slow-release, environmentally friendly commercial fertilizer product called Crystal Green®. The facilities produce more than 780 tons a year of fertilizer that is sold to the nursery and agricultural industry. Crystal Green® is also a key component in Clean Water Grow®, our retail fertilizer. This innovation saves on treatment and maintenance costs and increases capacity at the treatment facilities. Learn more about the Ostara process.
Clean Water Services' four wastewater treatment facilities recycle more than 31 dry tons of safe, nutrient-rich organic material from the more than 65 million gallons of wastewater we clean on average each day. This recycling process results in the production of biosolids. In fact, the more we succeed in cleaning our water, the more biosolids we can produce and recycle for beneficial use at local farms and rangeland in Eastern Oregon and the Willamette Valley as a soil amendment.
The solids that settle out during primary and secondary treatment, are routed to digesters—large cylindrical tanks kept mixed and heated to body temperature. The solids are treated for approximately three weeks, undergoing anaerobic digestion, which is digestion by bacteria that need no air. In their metabolism, methane gases are given off, which you will often see burning in a torch-like device in any wastewater plant, but at Clean Water Services, it's converted to energy.