The SU and CU wastewaters and RO concentrates are rich in chlorides, with values equalling 851 ± 615 mg Cl/dm3, 1423 ± 792 mg Cl/dm3, and 3746 ± 1544 mg Cl/dm3, respectively. Compared with organic substances, monovalent ions, such as Cl, are barely or not retained in the landfill prisms. Thus, the chemical composition of the leachate may be affected by the reconcentration
of Cl. Such re-concentrations may influence the biodegradation of landfill prisms and result in the need for greater quantities of chemical compounds (sulphuric acid and/or antiscaling products) to run the RO process.