Removal of organic pollutants and surfactants from laundry wastewater in moving bed biofilm reactor technology

The aim of the research was the testing of the moving bed biofilm reactor (MBBR) pilot plant treatment efficiency of industrial laundry wastewater. The two-stage MBBR pilot plant filled with AnoxKaldnesTM (Lund, Sweden) Z-MBBR carriers (Z-400) was used. The test was carried out on a place in the chosen laundry with the usage of real wastewater. The pilot plant worked in aerobic conditions with a coarse bubble aeration system with daily wastewater flow (Qd) equal to 0.6 m3/d (hourly flow Qh = 25 L/h). The hydraulic retention time was equal to 10.4 h. The concentration of dissolved oxygen in MBBR tanks was maintained on the level of 2–4 mgO2/L. The efficiency of chemical oxygen demand removal reached 77%–95%, biochemical oxygen demand (BOD5) 88%–96%, sum of anionic and non-ionic surfactants 91%–99%, anionic surfactants 94.8%–99.4% and nonionic surfactants 94.2%–99.5%. After the MBBR start-up period, the treated wastewater quality reached that required by law for wastewater discharged to surface waters. Excluding the periods of phosphorus deficiency, the MBBR installation reached the values of pollutant concentrations permitted by the legal regulations.