Lubna landfill

8 Remedial works8.1 Creation of landfill embankment with slope reinforcementsEspecially when the slopes are high and of considerable inclination, the construction of berms isthe most effective solution for slope stability reinforcement, however it requires area in the closevicinity of the landfill. Three technological roads are created on the landfill slopes at the levels of“130”, “140” and 160 m a. s. l. The crest of the landfill was designed at the level of 172 m a. s. l., i.e. approximately 60 m high (Fig. 16). By moderating and reinforcing the slope, the berm enablesthe achievement of additional capacity for waste disposal. The surface of the berm was made ofcohesive soil and compost. The construction of berms enables reaching additional capacityvolume for waste disposal.FIG.16 Designed Lubna landfill surface8.2 Cut-off wallThe bentonite cut-off wall barrier was constructed to protect the first aquifer against contaminationcoming from the landfill (Fig. 17). The permeability coefficient for the barrier wall is below 10 -9 m/s(resulting from the in situ BAT and laboratory tests). The initial hydraulic gradient for the bentonitewall is ca. i 0 =50, wheras the existing gradients in the field are i=2-3. In fact, the constructed cut-offwall is practically impermeable. The depth of the barrier wall was from 5.5 to 17 m, depending onthe subsoil conditions. Additional protection against migration of pollution is assured by directingthe flow from the vicinity to the leachate drainage system (Fig. 18). This would also protect thebentonite material against degradation caused by the leachate. Combination of a cut-off wall anda peripheral drainage system is safe and easy to build for the old sanitary landfill remediation. It isthe most effective and economic solution, if only applie on large areas.15