The application of moving bed bio-reactor (MBBR) in commercial laundry wastewater treatment

Highlights: • Application of MBBR for laundry wastewater treatment gives the good results. • Removal efficiency of organic pollutants, determined as BOD₅ and COD, was 95-98 % for BOD₅ and 89-94% for COD. • Deficit of phosphorus does not affect the efficiency of BOD₅ removal. Large, laboratory scale biological treatment tests of real industrial wastewater, generated in a large industrial laundry facility, was conducted from October 2014 to January 2015. This research sought to develop laundry wastewater treatment technology which included tests of a two-stage Moving Bed Bio Reactor (MBBR); this had two reactors, was filled with carriers Kaldnes K5 (specific area – 800 m²/m³) and were realized in aerobic condition. Operating on site, in the laundry, reactors were fed actual wastewater from the laundry retention tank. The laundry wastewater contained mainly surfactants and impurities originating from washed fabrics; a solution of urea to supplement nitrogen content and a solution of acid to correct pH were added. The daily flow of raw wastewater Qd varied from 0.6–1.0 m³/d. Wastewater quality indicators showed that the reduction of pollutants was obtained: BOD₅ by 95–98%, COD by 89–94%, the sum of anionic and nonionic surfactants by 85–96%. The quality of the purified wastewater after the start-up period met legal requirements regarding the standards for wastewater discharged into the environment.