## 2 Application of Membranes in Contamination Situations
### Groundwater Contamination
[99] carried out work to remove five pesticides, i.e., Thorate (O,O-diethylS-ethylthionethyl) phosphorothioate), Parathion-methyl (O,O-dimethylO-4-nitrophenyl phosphorothioate), Atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine), Dichlorovos (2,2-dichlorovinyl dimethyl phosphate), and Clofibric acid (2-(4-chlorophenyloneoxy)-2-methylpropanoic acid), in the brackish model groundwater solution using a laboratory direct membrane distillation (DCMD) system. It was found that the effectiveness of pesticide treatment with DCMD depends mainly on the properties of these compounds. Pesticides with low hydrophobic properties and low vapor pressure showed a high rejection rate (70-99%), while compounds with high vapor pressure or high hydrophobicity reduced rejection (30-50%) with a water recovery of 75%. It was also found that organic (humic acid) and inorganic ions (Na\({}^{+}\), Ca\({}^{2+}\), Mg\({}^{2+}\), Cl\({}^{-}\) and SO\({}_{4}\)\({}^{2-}\)) do not significantly affect the degree of pesticide rejection by DCMD [99]. [PERSON] et al. [100] also started work on the removal of chlorinated pesticides, mainly \(\alpha\)-HCH, \(\beta\)-HCH, \(\gamma\)-HCH, HCB, DDE, DDD, and DDT from groundwater. A LAB M-20 membrane, a small-scale separation test unit, with a LabStack M20 membrane module, with a nominal capacity of 30 dm\({}^{3}\)/h, at a maximum pressure of 6.0 MPa, was used for the tests. Due to the requirement of high-quality permeate, RO98 pH reverse osmosis membranes (thin-layer polypropylene composite) were used. Observed removal rates of chlorinated pesticides ranged from 98.4% to 99.7% in the presence of high salt content. The separation efficiency was slightly higher for DDT and its derivatives than for HCH isomers [100]. [PERSON] et al. [101] started work on removing chlorinated volatile and non-volatile organic compounds from groundwater, such as trichlorethylene (TCE), tetrachlorethylene (PCE), cis-1,2-dichloroethylene (DCE), 2,2-dichloropropane (DCP), and vinyl chloride (VC). Three types of membranes were used: ceramic microfiltration membrane Pall Membralox (made of \(\alpha\)-Al\({}_{2}\)O\({}_{3}\)), four polymer nanofiltration membranes (namely DK and DL membranes from GE Osmonics, NF90 and NF270 from Dow Filmtec), five reverse osmosis membranes (AK and AG-GE Osmonics, BW30, BW30 LE, and BW30 XFR from Dow Filmtec, fouling resistant). The use of nanofiltration membranes allowed for the reduction of pollutants at the level of almost 100% (with the exception of VOCs), with a maximum operating pressure of up to 3 bar. On the other hand, microfiltration membranes and reverse osmosis membranes did not give positive results, which was probably due to the adsorption of hydrophobic VOC compounds on the membranes and the inability to pass the solution through the membrane matrix [101]. The problem of groundwater contamination with chlorinated organic compounds such as trichlorethylene (TCE), tetrachlorether (PCE), polychlorinated biphenyl (PCB) and carbon tetrachloride (CTC) was also addressed by [PERSON] [102; 103]. In order to remove the contamination, he used commercial microfiltration membranes made of polyvinylidene fluoride (PVDF), which were functionalized with poly (acrylic acid) (PAA) or poly(methacrylic acid) (PMAA). Functionalization caused deprotonation of hydroxyl groups, as a result of which the membranes became hydrophilic at pH \(>\) pKa. In addition, Pd-Fe nanoparticles with sizes \(<\)20 nm were embedded in the pores of the membranes. The membranes thus obtained were used in the removal of organic contaminants from the Louisville, KY landfill.