This study investigates the influence of four imidazolium ionic liquids (ILs) present in wastewater on the activated sludge process. In addition, experiments with inactivated sludge to assess the capacity of this sorbent to remove ILs from the wastewater were conducted. It occurred that the presence of ionic liquids in wastewater reduces biomass growth and size of the sludge flocs. The strongest effect has been found for IL 6 (1-hexyl-2H-3-methyl-4,5-dimethylimidazolium iodide) with the longest alkyl chain length. Also, the degree of ILs removal increases with the alkyl chain length and decreases with the increase of initial concentration of ILs in wastewater. IL 6 reaches the highest degree of ILs removal from wastewater but inhibits the biomass growth and growth of sludge flocs in a greater extent than other tested compounds. Moreover, it was confirmed that newly synthesized ionic liquids can be adsorbed onto inactivated sludge. IL 6 could be adsorbed in a higher degree than other ionic liquids. This adsorption was described by Langmuir isotherm, whereas adsorption of other ionic liquids was described by Freundlich isotherm.
One of the most important problems concerning contaminant transport in the ground is the problem related to the definition of parameters characterizing the adsorption capacity of ground for the chosen contaminants relocating with groundwater. In this paper, for chloride and sulfate indicators relocating in sandy ground, the numerical values of retardation factors (Ra) (treated as average values) and pore groundwater velocities with adsorption (ux/Ra) (in micro-pore ground spaces) are taken into consideration. Based on 2D transport equation the maximal dimensionless concentration values (C*max c) in the chosen ground cross-sections were calculated. All the presented numerical calculations are related to the unpublished measurement series which was marked in this paper as: October 1982. For this measurement series the calculated concentration values are compared to the measured concentration ones (C*max m) given recently to the author of this paper. In final part of this paper the parameters characterizing adsorption capacity (Ra, ux/Ra) are also compared to the same parameters calculated for the two earlier measurement series. Such comparison also allowed for the estimation of a gradual in time depletion of adsorption capacity for the chosen sandy ground.