Lubna landfill

8.2 Leachate drainage systemIn 1998, an encircling drainage system around the landfill was constructed (Fig. 19). In addition,“finger” pipe drains were installed in the bottom of the berms to direct the leachate from the landfillto the encircling drainage (Fig. 20). Additionally, the drainage system was extended for rain waterfrom the technological roads and slopes (Fig. 4).FIG. 19 Construction of the peripheral leachate drainageFIG. 20 Construction of “finger” pipe drainsThe drainage cover was made of graded permeable soils to provide protection against clogging,using a filter construction. After about one year of exploitation of the drainage system, the upperfilter layer appeared to be almost completely clogged, which caused stagnation of the peripheraldrainage on the top. Clogging occurred in the upper 03 m, where the d 10 diameter decreased from0.3 to 0.03 mm (Fig. 21). The filter clogging results from accumulation of surface runoff from thelandfill slopes, both from rain and leachate sources. A periodic drainage conservation scheme hasbeen designed. Then, the upper 0.3-0.5 m of the filer layer was removed and replaced. Theorganic matter content in clogged filter material was 2-5 %. This results from organic pollutantsleaching from the landfill and erosion of the slope surface, which was covered by compost. Afterreplacement of the upper filter material, the drainage system regained its full functionality.17