DISPOSAL OF COMMUNAL WASTE
In Macedonia, there is no other modern facility for the disposal of solid waste, nor are there any facilities for its treatment with some of today’s procedures for thermal-biological treatment.
The utility problems are growing in proportion of the population. The region of Skopje is the most densely populated area of the Republic of Macedonia. According to the last census, there were 545,000 residents, or over 25% of the total population of the state.
100,000 inhabitants live in rural settlements, and the rest in the metropolitan area.
According to its dimensions, the landfill Drisla can receive approximately 26 million m3 million tons of solid waste, corresponding to the complete accepting waste from the households and the commercial establishments on the territory of Skopje and beyond, for at least 30 years.
The department for receiving waste at the landfill PE “Drisla” is obligated to receive the communal and the medical waste, which is collected from the territory of the City of Skopje. They are also obligated for the destruction or disposal of waste from other commercial entities and government institutions at their request, bearing in mind that the waste is on the list of types of permitted and disposable waste.
The technological process starts from the entrance of the landfill. First, the utility vehicles are measured on electronic scales, which determine the weight of the waste.
After weighing, the vehicles move in the direction of the landfill’s so-called time roads i.e. they are accepted by the Department for disposal.
At the Department for disposal , in the area designated for unloading the waste or the so-called meeting place, the Department for waste receiving maneuvers the waste , and brings it to the so-called platform where it is unloaded.
The construction machine – Loader performs a short transfer of the waste out of the platform and then a bulldozer takes over bringing it to the planned area and placing it in layers. Then, the construction machine- Compactor executes the compression of the waste.
The slope of the poured layers has a longitudinal decline of 4%, which allows a filtration of the rainfall water into earth drains, which significantly reduces the amount of filtrate and excludes the possibility of contamination of water. The body of the landfill consists of a plateau at an elevation of 440 m above sea level and slopes that connect the plateau with the natural terrain. The inclination of the slope is 1:2. For every 10 m height, horizontal tape is applied, a so called “Bermi” with a 5.0 meter width. The surface of the final plateau is 33 ha. The created slopes are covered with inert material, then with humus of 0.7 m thickness, which then grasses. At the lowest elevation point of the landfill, there is a filled dam, so called prism filter, serving as a protection of the soil from surface erosion.
The process of biological decomposition or fermentation of waste takes place in 2 phases: aerobic (oxygen present) and anaerobic (no oxygen present). As a result of these processes, filtrate (filtrate contains increased amounts of chloride and sulfate), gases (methane, hydrogen, hydrogen sulfide) and a certain amount of heat appear.
The amount of filtrate is 10 to 15% of the total rainfalls. This is however, dangerous in a sanitary sense, due to its pollution, which is 5 to 10 times the pollution of local waters.
The process of separating the gases lasts 5 to 10 years, and even more after the landfill is closed.
The duration of treatment and mineralization of the waste is 15 to 25 years after closure of the landfill.
The technological process used for the sanitary landfill is important because of several aspects:
– Stability of the landfill body;
– Removing the possibility of creating an air gaps where the produced landfill gas would be piled up;
– Optimal filling of the landfill; and
– Reducing the possibility of leachate penetration into the groundwater.
After the performed operations at the landfill, the utility vehicles are directed to the launderette where the undercarriage is being washed.
In the past years of operation of the landfill Drisla, the following amount of waste has been deposited in tons: