MBBR Helps Reduce BOD Loading In Paper Plant Effluent

Inland Empire Paper Company (IEP), located in Millwood, WA specializes in the production of newsprint paper using a combination of mechanical pulp and recycled newspaper pulp. IEP produces an average of 525 tons per day of newsprint and specialty paper products in 20 to 40 pound weight paper. Waste wood chips collected from local sawmills are processed to produce up to 475 tons of thermo-mechanical pulp (TMP) per day. IEP also recycles newspapers collected from around the country for the production of up to 350 tons of recycled newspaper fiber per day. The recycled newspapers undergo a deinking process and are blended with the TMP prior to the bleaching process. IEP then dilutes the bleached pulp with water to lower its consistency to approximately 1% solids for introduction to the paper machine. Water is removed via a press and dryer process to produce paper with approximately 8% final moisture content.

IEP generates wastewater flows averaging 3 MGD (473 m3/hour), loaded with high strength BOD5. The wastewater is deficient in nitrogen and phosphorus, so ammonia and phosphorous are added to the system as essential nutrients for the activated sludge system.

IEP also has a series of production campaigns for High Bright Paper runs that lead to higher organic loading and sludge bulking. The High Bright Paper campaigns run for a period of two days during which the wastewater treatment plant can see influent MLSS levels over 5,000 mg/L.