Leachate Toxicity Research

Leachate management challenges at wastewater treatment plants (WWTPs) vary by POTW size, percent of leachate to overall flow, leachate composition, regional differences, and regulatory challenges, and are known to commonly include ammonia removal inhibition and biological treatment upset. Both of these issues can be seen in the activated sludge process of the treatment train during biological nitrogen removal and are affected by leachate nutrients such as nitrogen and phosphorus as well as other compounds in the leachate matrix. As wastewater treatment operators are increasingly refusing to accept landfill leachate, this study will gauge the specific impacts of leachate on biological wastewater treatment and provide data that will allow WWTPs to decrease biological treatment disruptions and ammonia removal inhibition that occur as a result of leachate management.

In this study, the effects of leachate on nitrifying activated sludge are quantified by performing specific oxygen uptake rate (SOUR) tests. Several different leachates are tested, as well as various concentrations (from 1% v/v leachate to activated sludge ratio, to 75% v/v leachate to activated ratio sludge). Additionally, the effect of landfill leachate on biological nutrient removal, nitrification, and effluent quality is assessed by adding leachate to sequencing batch reactors (SBRs) that mimic the secondary treatment process in wastewater treatment.

This study quantifies and determines the effect of landfill leachate not only on wastewater facility operation, but also on the treatment efficacy. By quantifying this, leachate pre-treatment can be targeted and impacts on wastewater treatment plant operations can be quantified.