Characteristics and natural attenuation of the Pfifiskiila landfill leachate

• Published in: Proceedings of the Estonian Academy of Sciences. Chemistry Vol. 54; no. 1; pp. 35 - 44
• Main Authors: Selberga, Aare, Viik, Malle, Peet, Kai, Tenno, Toomas
• Format: Journal Article
• Language: English
• Published: 01.03.2005
• ISSN: 1406-0124

The leachate composition can vary throughout a landfill, and leachate production decreases with placement of the final cover. Anaerobic decomposition, which can produce a leachate with high concentrations of biogenous pollutants, occurs in the covered landfill. Pdaskiila landfill (Tallinn, Estonia) was built as a temporal landfill on peat deposits in 1974. In June 2003 the landfill was closed and covered but the leachate will filter over many years. In March 2004 the leachate contained 62.6 mg/L total nitrogen (Mot), 6.9 mg/L total phosphorus (Pm), 668 mg O2/L COD, and 160 mg 02/L BOD7. In the leachate 91% of the nitrogen was determined as ammonia. In March 2004 the content of pollutants was higher than the corresponding values analysed in 1971 and 1993. It is connected with methane production in the closed landfill. The effluent enters the Vdana River through the Paaskiila River and in the sampling place of the Vaana River the values of pollutants were 2.4 mg/L Mot, 0.05 mg/L Ptc,t, 26 mg O2/L COD, and 1.7 mg 02/L BOD7. The concentrations of pollutants had decreased as a result of dilution in the rivers but it is an insufficient antipollution measure.