Assessment of the impact of seepage waters in landfills for solid waste and activated sludge on the water quality of small rivers in the humid zone

Based on seasonal studies of chemical compound of drainage waters of landfill site, active sludge dump and small rivers (Neluksa and Sel'gskaya) draining their territory, the chemical markers of the waste dump impact were established. Water and chemical balance of waste dumps is established and the volumes of different chemical components discharge with drainage waters and rivers into the Lake Onego are calculated. River heads were not contaminated and were considered as a background stations. Drain waters of active sludge dump strongly contaminate the Sel'gskaya river water downstream their inlet point. Contamination was established by the following chemical variables: mineral composition (Na+, K+, Ca2+, Mg2+, Cl-, SO42-, HCO3-), organic matter (BOD5, Color, CODCr, CODMn, TOC), nutrients (P-tot., P-min., NH4+, NO2-, N-tot., N-org.), gases (CO2, O-2), heavy metals (Mn, Cr, Co, Zn, Ni, Cu), conductivity, suspended matter, pH, phenols, and synthetic surfactants. These components were considered as markers of active sludge impact. Active sludge dump makes up 20% of suspended matter, 17% of labile organics (BOD5), 14% NO2-, 3.2% N-org., and 10% N-tot. of the total river discharge. All volume of NH4+ discharge in the lake is supplied by active sludge dump. The sound influence was also observed for CODCr (2.5%), CODMn (2.0%), Cu (4.5%), Zn (2.7%), TDS (3.5%), Cl- (2.7%) and Na+ (2.5%). Drain waters of landfill site affected the Neluksa River in a much lesser degree, differences in chemical composition downstream the drainage waters inlet were established for Na+, Cl-, pH, HCO3-, CO2, NO3-, total Fe, Mn, which can be considered as markers of landfill site impact. The share of landfill site in NH4+ discharge is 12%, N-tot - 2.0%, Cl- - 2.5%, and Na+ - 1.2%. Total petroleum hydrocarbons contamination in the region has diffusive character and mainly originates from precipitation.