Vinča landfill leachate characteristics prediction by the leaching method

Abstract

Under the newly implemented waste management policy in European Union countries, sanitary landfilling constitutes the fourth and the least preferred of the alternative management options for the disposal of solid urban wastes. Landfills generate emissions over long periods, often longer than a lifetime. The longest lasting emission is leachate: leachate production and management is now recognized as one of the greatest problems associated with the environmentally sound operation of sanitary landfills. These liquid wastes can cause considerable pollution problems by contacting the surrounding soil, ground or surface waters and, are therefore considered major pollution hazards unless precautionary measures are implemented. Landfill leachate characterization is a critical factor in establishing a corresponding effective management strategy or treatment process. This paper summarizes leachate quality indicators, and investigates the temporal variation of leachate quality from municipal solid waste. The toxicity of leachates from the municipal solid waste landfill "Vinča" in Belgrade, the capital of Serbia, was characterized using toxicity characteristics leaching procedures (TCLP). The "Vinca" landfill was established in 1978 as one of several municipal landfills. Since the 1990-ies the "Vinča" landfill has been the only operating landfill servicing the Belgrade Metropolitan area, the biggest city in Serbia, with 1,576,124 inhabitants in the larger-city area, and 1,273,651 inhabitants in the inner-city area. The total average amount of solid wastes deposited in the landfill is estimated to be 1100 tons/day. The landfill site is not lined and the tributary flows through the centre of the site-in some places directly under the mass of refuse. No consideration has been given to the protection of ground waters, surface runoff or drainage. Local authorities plan to expand the landfill by 0.4 km2 to a total of 1.3 km2. Chemical analysis was performed on the samples and the temporal variation of several parameters was monitored including pH, COD, chlorides, sulfates, nitrates, ammonia nitrogen, hardness, and heavy metals. The COD and pH were related to the biological activity within the landfill and the results indicated differences between the samples due to waste age. The concentrations of heavy metals, sulfates, nitrates, chlorides and ammonia nitrogen in the leachate were low, indicating their initially low amount in landfilled waste or their flushing with moisture contributing to a reduction in their concentrations.

Komunalni čvrsti otpad iz Beograda odlaže se na deponiju "Vinca" od 1978. godine, a od 1987. do 2002. godine odloženo je oko 4.100.000 tona. Jedna od posledica odlaganja čvrstog otpada na deponiju jeste pojava procednih voda/filtrata. U okviru eksperimentalnog dela rada vršeno je izluživanje primenom TCLP metode (Toxicity Characteristic Leaching Procedure) uzoraka otpada koji su bili odloženi 6, 12 odnosno 24 meseca pre uzorkovanja. U rastvorima dobijenim izluživanjem koncentracije teških metala (Cu, Cd, Pb i Zn), hlorida, sulfata, amonijaka, nitrata i nitrita su bile niske, i nisu se znatno razlikovale za uzorke različite starosti. Dobijeni rezultati pokazali su da se pH vrednost i HPK (hemijska potrošnja kiseonika) menjaju u zavisnosti od starosti ispitivanog odloženog materijala, odnosno dostignutog stepena stabilizacije.