FOREST GROVE WATER RESOURCE RECOVERY

Forest Grove Facts • Provides a higher level of treatment over many activated sludge systems, as it utilizes biological phosphorus removal in the facility and nitrogen removal in the Natural Treatment System • Operates 24-hours a day, 365 days a year • Meets over 1,5001 permit conditions, including monthly, weekly and daily limits established to protect the Tualatin River • Serves a growing population of over 20,000 people • Cleans an average of 7 million gallons of wastewater per day • Takes advantage of resource sharing by utilizing the Rock Creek facility for solids treatment AERIAL VIEW OF FOREST GROVE NATURAL TREATMENT SYSTEM IN FOREST GROVE, OREGON • Supplies flow to the Fernhill Natural Treatment System which The Forest Grove Water Resource Recovery Facility, located on Fern Hill Road in Forest improves the quality of Grove, is a nationally acclaimed, state-of-the-art facility, serving Washington County water before its discharge to the residents in the cities of Forest Grove, Cornelius and Gaston. Despite being one of Clean Tualatin River Water Services smaller facilities, Forest Grove is one of the most complex treatment facilities in the Pacific Northwest. • National Association of Clean Water Agencies (NACWA) Gold Award for The Forest Grove facility treats an annual average of seven million gallons of used water 100% permit compliance achieved each day to among the highest safety and quality standards in the nation. In addition to over multiple years advanced biologic processes, the facility welcomed the planting of over one million native 1 1,500 without the NTS System; 1,820 with plants, which transformed the former effluent lagoon ponds into the 92-acre Fernhill the NTS System Natural Treatment System that harnessed the capabilities of natural systems to improve the quality of water before its discharge to the Tualatin River.

This facility is connected to two of our other facilities, which aids in mitigating peak flows and helps treat the water and remove valuable resources. During wetter months, the system conveys excess flows through preliminary processes before sending the water to the Rock Creek facility. Staff also dynamically alter the flow path of the facility to react to flood conditions. During dryer months, liquid flows from the Hillsboro facility to Forest Grove for additional treatment.

Forest Grove was originally constructed in 1951 and has seen numerous transformations to its treatment process over the years. This facility centralized a scattered system of inefficient wastewater treatment plants, creating one of the most efficient and advanced facilities in the world. FOREST GROVE WATER RESOURCE RECOVERY — PROCESS

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Rock Creek Water A Resource Recovery Facility

Liquids Recovery Solids Recovery At the Forest Grove Facility, used water flows through the plant through a series of processes: preliminary, secondary, disinfection and effluent discharge before it is A The first half of the job at discharged to the Natural Treatment System. a water resource recovery facility is to remove foreign constituents 1 Preliminary Process from the liquid flow stream. Those Flow from homes and industry eventually comes to the Forest Grove Headworks foreign constituents are resources Building. Headworks prepares the incoming flow for downstream treatment by that can be reclaimed. The typical screening out rags and large objects that can cause equipment plugging and wear. processes in solids treatment consist As the flow leaves the Headworks Building, it is routed to the Influent Pump Station. of thickening, digestion, dewatering, and phosphorus recovery. The Influent Pump Station pumps and measures the flow up to the Grit Removal Structure where heavy, not readily biodegradable objects such as sand, coffee grounds However, no solids treatment is and corn kernels are removed. This “grit” is usually light enough to escape capture in performed at the Forest Grove the headworks, but still heavy enough to easily separate from the rest of the flow. facility. The solids that are wasted from Secondary Treatment are pumped to the Rock Creek facility 2 Secondary Treatment for treatment. There are many types of secondary treatment. The Forest Grove Facility employs conventional activated sludge. This means an environment is created in aeration basins FOREST GROVE WATER RESOURCE RECOVERY — PROCESS that allows the natural bacteria in wastewater to grow and thrive. The bacteria then consume contaminants in the water. As the flow leaves the aeration basin, secondary clarifiers form a wide spot in the flow that slows down the water. Bacteria sink to the bottom and sludge pumps return most of the bacteria to the front of the aeration basin to meet the incoming flow and remove further contaminants. A portion of the bacteria is removed (wasted) and sent to the Rock Creek facility to maintain a stable aeration basin population.

3 Disinfection Disinfection inactivates harmful microorganisms. Forest Grove accomplishes this by the use of ultraviolet (UV) light. The plant flow passes in front of UV light, which inactivates the bacteria by damaging them so they can no longer multiply.

4 Effluent Discharge After the flow leaves the plant, it is sent to the Natural Treatment System. The NTS creates an ecological bridge between the treatment facility and the watershed. Water is cleansed further, cooled and naturalized before it is returned to the Tualatin River, helping it maintain a healthy flow year around.

5 Natural Treatment System The NTS consists of a vertical flow wetland and a natural treatment wetland.

The vertical flow wetland is designed to remove ammonia from the flow stream. Water passes through a media of rocks where bacteria are allowed to grow. These bacteria consume the ammonia in the water and convert it to nitrate.

The natural treatment wetland is a constructed wetland comprising of a number of different shallow ponds. Natural wildlife and plants thrive, and the plants that grow consume nutrients that are in the water. As these plants grow, they provide shade, which shields the flow from the warmth of the sun. The natural evaporation of the water also helps to cool the remaining flow.

As the water works its way through the wetlands, it eventually ends up at the Tualatin River. The flow is cooler than when it went into the wetlands and has a lower nutrient level and contributes to the health of the Tualatin River. FOREST GROVE WATER RESOURCE RECOVERY — FERNHILL

Fernhill is part of more than 700 acres in Forest Grove owned by Clean Water Services for water resources management. Fernhill utilizes natural treatment systems or wetlands to improve water quality by removing nutrients, cooling, and naturalizing the water after initial treatment at the Forest Grove facility. In the summer, 5 million gallons of water are cleaned each day at Forest Grove and then Fernhill before flowing to the Tualatin River.

In 2014, 90 acres of old sewage lagoons were transformed into treatment wetlands by draining the ponds, then drying and excavating more than 200,000 cubic yards of soil into precise contours and depths. Using 15 control structures and 2,400 feet of piping, the water was managed to encourage the growth and establishment of over 1 million native wetland plants and 4 billion seeds, planted both for water quality and for habitat. Birds and wildlife have taken to the 180 logs and snags that were anchored into place, and human visitors are enjoying the 1.1 mile loop around Fernhill Lake, trail improvements, outdoor meeting areas and wildlife watching.

Innovations Algae Study Clean Water Services scientists are researching the potential for using natural biological processes that occur between water, plants, and microorganisms to remove Clean Water Services is in the second contaminates from water. summer of a partnership with the United States Geological Survey Floating Islands (USGS) to better understand how In floating wetlands, plants grow out of a dense but porous foundation that allows treated water from the Fernhill NTS roots to grow throughout. Plants are beautiful and provide habitat while the foundation impacts water quality in the Tualatin and roots create a surface for microbes to live. Bacteria and other microorganisms River. The study is focusing on the digest organic matter and nutrients circulating in the water and produce a sticky film presence and abundance of various called biofilm that traps total suspended solids and fine particulates. types of benefical algal species and harmful cyanobacteria in the Nutrient Filter river. The wetlands of the NTS may The current nutrient filter design, aims to remove ammonia, which is harmful to seed beneficial algae that grow as fish and wildlife. This filter uses a six-foot deep bed of gravel that acts as a host for they travel downstream, increasing ammonia-removing microbes that occur naturally in streams and rivers. Clean Water dissolved oxygen in the lower Tualatin Services’ approach is to actively maximize the population of these microbes (many times River. Conversely, if water from the more than in nature) so that the filter removes ammonia before water is returned to NTS contains cyanobacteria, there the Tualatin River. Once the system has been optimized, the surrounding area will be could be negative water quality landscaped and an ADA accessible trail will circle the facility. impacts downstream.

Denitrification Wetlands Data from the 2019 study suggests This project evaluated the effectivness of using wood chips and biochar (a charcoal-like that NTS water quality and algal substance) media to reduce copper and nitrate in water. Effluent from the Nutrient seeding have measurable effects Filter was fed into two pilot reactors where several flow varibles and media types were downstream. (was cyanobacteria tested over a two year period. A substantial reduction of both nitrate and copper was detected?) Monitoring results will be observed year-round at a range of flow rates. analyzed alongside operational records to evaluate whether certain actions can be taken in the NTS to enhance water quality and promote beneficial algal growth.

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