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DariTech, Inc. announced that earlier this year it won a competitively bid contract with the Port of Tillamook Bay (POTB) to design, build and start-up a fully bonded, turnkey $5.6 million manure anaerobic digester and 1.2 megawatt (MW) electricity generator at the POTB facility in Tillamook, Oregon. DariTech is supplying all technology, equipment, services and management to rapidly design, permit and build the Plant.
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The Plant will process the manure from the equivalent of 5,000 milking Holsteins from the Tillamook community dairies by producing biogas used as fuel to generate electricity through a state-of-the-art 1.2 MW combined heat and power unit. With no additional off farm substrate, 100% of the energy produced will come from the cows. At full operation, planned for 2013, the Plant will generate nearly 10 million kilowatt hours of electricity per year- true cow power! The Plant will serve several nearby dairies whose manure will be
trucked to the Plant.

Featuring aboveground glass-fused-to-steel insulated tanks, the Plant meets the POTB need for a small footprint at its historically sensitive site. DariTech's Plant fits well within the boundaries of the foundations of what was a World War II blimp hangar. The three digestion tanks, 84 feet diameter by 28 feet tall, will be covered with DariTech's own flexible membrane roof. Slurry storage and processing will take place in two smaller tanks, 36 feet in diameter by 28 feet tall. A 4,400 square foot building will house solids dewatering and fiber processing via DariTech's BeddingMaster in- vessel drum. With DariTech's custom in-house PLC control system, programming is simple, fast and effective.
DariTech photo
The Plant operates by taking in liquid manure from dairies delivered in tanker trucks, which return digested and separated manure to the dairies for agronomic land application. A touch screen at the load/unload station communicates directly with the system PLC, allowing tracking of all incoming and outgoing manure. The incoming manure is preheated to about 100 degrees Fahrenheit, the operating temperature of the mesophyllic digester. The prepared manure is pumped into the digester tanks, where it stays for up to 25 days. Periodic mixing ensures a low parasitic load for the system operation, with no moving parts inside the tanks. Anaerobic bacteria feed on the organic matter and produce methane rich biogas which bubbles to the top of the tank. The Biogas is removed, cleaned and injected into the engine which turns the generator which is connected to the electrical grid. Liquid from the digester is dewatered with the resulting fiber further processed. Treated liquid nutrients are hauled back to the dairies for application to their cropland.

All of the Plant products are put to good use. Electricity from the Plant will be supplied to Tillamook PUD. The POTB will sell the fiber to a variety of nurseries and horticultural users across the Pacific Northwest and northern California. Liquid nutrients are applied to cropland in the Tillamook community. The POTB will obtain carbon offset value for destroying methane which would be otherwise released to the atmosphere (methane if released into the atmosphere is 21 times more potent than carbon dioxide as a greenhouse gas). The creation of this Plant supports the long-term sustainability of dairy farmers in the Tillamook community.

About DariTech (www.daritech.com)
DariTech is a premier dairy service and supply company, with a complete manufacturing facility at its Lynden, WA headquarters. DariTech has for 22-years supported dairy farmers from the barn to the milking parlor to cropland through efficient and cost-effective systems and equipment. DariTech provides round-the-clock high quality service for all of its products.