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WHAT’S COMES INTO WEST POINT? Department of Natural Resources and Parks Typical Flows by Source During Winter Months Division Residential 29% Stormwater Inflow and Groundwater Infiltration 53% 17% Business West Point Treatment Process 1% Industrial Processes

PRELIMINARY TREATMENT PRIMARY TREATMENT PRODUCTS

Water Treatment Flow diversion over 300 million gallons per day Industrial On-site Use odor odor sand odor control control odor control control filter Tertiary hypochlorite Treatment Recycled Water Pump (bleach) Pump Bar Grit Primary Stations Screens Removal Clarifier sodium Puget Sound Sedimentation Aeration Tanks Tanks Tanks Disinfection bisulfite Trash Dechlori- Pump nation Clean Euent to landfill Solids Solids WEST POINT Solids Treatment

FACTS odor odor odor control control Design average wet weather flow: control 133 million gallons per day Design peak secondary capacity: Blend Anaerobic Centrifuge Tank Gravity Belt Digesters Dewatering Land Application 300 million gallons per day Thickener Design maximum capacity: of Nutrient-rich 440 million gallons per day during Loop peak storms Heat

Outfall pipe: 3,600 feet long, Biogas 240 feet deep, 600-foot diuser Heat used Recycled water produced: Gas within plant up to 220 million gallons per year Boilers and to warm Average dry weather flow: buildings Loop produced: 100 million gallons per day Money about 50,000 wet tons per year $ from sale of Average wet weather flow: Cogen green energy Biogas generated: 120 million gallons per day Energy 550 million cubic feet per year Raw Pump Engines 1801_8805w_WpProcess.ai At West Point Treatment Plant

About 100 million gallons of wastewater (sewage) come · After four hours in the aeration tanks, the wastewater enters Nutrients: Loop® Biosolids through West Point every day from homes and businesses in a large separation tank called a clarifier. In the clarifiers, the Solids treatment produces a nutrient-rich biosolids product the Seattle and North King County areas. During heavy rain, bacteria will settle to the bottom of the tank and most called Loop® that is sold to farms and forests as an alternative West Point treats up to 440 million gallons per day. This (90 percent) will be returned to the aeration tanks to be used to chemical . Loop® can be composted further to wastewater carries trash, dirt, organic , bacteria, again to breakdown the organic waste. The remaining create GroCo®, a retail product for home gardens and pathogens, and small amounts of chemicals. 10 percent will be reused and sent to solids treatment. landscapes.

Disinfection: ‘Zapping Pathogens’ STEPS OF WASTEWATER TREATMENT Energy Preliminary Treatment: Taking Out the Trash and Grit · The wastewater is disinfected with a small amount of bleach Biogas from the solids treatment process is converted into (sodium hypochlorite) before being piped to Puget Sound. · Metal screens filter out trash items, such as cleaning wipes, electricity and used on the treatment plant for heating tanks The water will naturally dechlorinate by the time it enters feminine products and paper towels. and buildings. Some of the gas is also scrubbed, removing Puget Sound. impurities, and sold to local utility companies for use as a · The wastewater then enters a tank that has which air is natural gas in local homes and businesses. This helps reduce added to help separate the grit (dirt, sand and gravel) out of the Wastewater Treatment Division’s carbon footprint. the water. SOLIDS TREATMENT Biological treatment and dewatering · The trash and grit collected during preliminary treatment are · The organic solid waste that is removed during primary and trucked to a landfill. YOU CAN HELP secondary treatment is combined and put in large tanks · Flush only human waste and paper down the toilet. called digesters. These big tanks use bacteria and heat to Primary Treatment: Organic Waste Removal Other ”flushable” products are NOT good for pipes and help digest, or break down, the organic solid waste. · Next the wastewater enters large tanks where it sits for sewer systems. · After about 30 days in the digester, excess water is removed about six hours. During this time, cooking oils, grease, soaps using a centrifuge (high-powered spinning machine), and the · Use simple, biodegradable (“green”) personal care and and hair naturally float to the surface. Heavier organics, such material is now called biosolids. cleaning products. Find recipes to make your own! as human waste and food waste, settle to the bottom. http://www.kingcounty.gov/depts/health/chronic-diseases/ · Biosolids are used as a nutrient-rich soil amendment for crops · Scrapers remove the organic solids from the top and bottom asthma/patients/green-cleaning.aspx and forests in Washington state. of the tank. Those materials are piped to the solids · Control rainwater by installing a rain garden or rain barrel at treatment area where they will be recycled (see Solids your home. You can also prevent runo by cleaning Treatment). your car at a car wash, scooping your dog’s waste, and · This process removes about 50 percent of the organic Recycled Water picking up . These actions all help protect our local solid waste. After disinfection, some water will be further treated using water quality. advanced filtration and disinfection to produce water that is Secondary Treatment: Helpful Bacteria at Work approximately 99.9 percent cleaner than when it came into the · The wastewater then flows into aeration tanks, where warm plant, and clean enough to be recycled. Recycled water is used air is continuously added. on the treatment plant as well as to water places like golf · The warm, oxygen-rich environment in these tanks activates courses and parks, instead of using valuable drinking water for naturally occurring bacteria. These bacteria consume the . Using recycled water helps keep water in our rivers remaining organic material in the wastewater. and streams for use by people and wildlife. Department of Natural Resources and Parks Wastewater Treatment Division