Archives of Environmental Protection

Abstract

The aim of the study was to determine the impact of selected factors on the reduction of organic pollutants, expressed in BOD 5 and COD Cr , in wastewater treated in a laboratory scale model of moving bed biofi lm reactor (MBBR). The factors included in the experiment: the degree of fi lling the fl uidized bed with biomass carriers, hydraulic load, and aeration intensity. The tested model of the bioreactor consisted of fi ve independent chambers with diameter D = 0.14 m and height H = 2.0 m, which were fi lled with biomass carriers at 0%, 20%, 40%, 60%, 70% of their active volume. During the test period, hydraulic loads at the level of Q h1 = 0.073 m 3 •m -2 •h -1 and Q h2 = 0.036 m 3 •m -2 •h -1 were applied, which ensured one-day and two-day sewage retention, respectively. The said reactors were subjected to constant aeration at P 1 = 3.0 dm 3 •min -1 and P 2 = 5.0 dm 3 •min -1 . The highest effi ciency of the reduction of the analysed indicators was demonstrated by reactors fi lled with carriers in the degree of 40-60%. Based on the statistical analyses (the analyses of the ANOVA variations and the Kruskal-Wallis test) carried out, it was found that the studied factors signifi cantly modifi ed the mutual interaction in the process of reducing BOD 5 in treated wastewater of the reactors tested. The signifi cance of the impact of the discussed factors on the values of the studied indicators in treated wastewater depends on mutual interactions between the investigated factors.