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01.16.22 | Michelle C. Torres, M.S.

The Effects of Leachate Recirculation on Chromium and Nickel Concentrations in C&D Leachate

What effect does leachate recirculation at construction and demolition debris (C&DD) landfills have on the concentrations of chromium and nickel in leachate? Chromium and nickel are transition metals that can be found associated with naturally occurring minerals or man-made materials. Both of these metals are components in stainless steel, which is a common construction material that may be disposed of in a C&DD landfill. Read More
Tags: Environmental, Waste Management

10.09.20 | Michelle C. Torres, M.S.

Changes in Calcium and Magnesium Concentrations in C&D Leachate with Recirculation

In C&D debris, the dissolution of minerals from drywall and concrete contributes to elevated calcium and magnesium concentrations in leachate. Does leachate recirculation increase the concentrations of calcium or magnesium in C&D leachate? The expected answer would be yes; however, the interaction of recirculated leachate is not that simple, as our data shows. Read More
Tags: Civil Engineering, Environmental, Waste Management

01.18.18 | Michelle C. Torres, M.S.

The Effects of Leachate Recirculation on Arsenic Concentrations in C&D Leachate

Leachate recirculation is one possible method of leachate management at construction & demolition (C&D) debris landfills. Arsenic is of particular concern in construction and demolition (C&D) landfill leachate. It is naturally occurring in soil and rocks, and C&D leachate commonly exhibits arsenic concentrations higher than “natural” groundwater; and, even if not detected in leachate, the leachate can mobilize the naturally occurring constituents. Any of these occurrences may pose a risk to human health and the environment. The data available for our three study sites show that C&DD leachate contains elevated concentrations of arsenic. Does leachate recirculation increase arsenic concentrations? Read More
Tags: Environmental, Waste Management

04.05.17 | Michelle C. Torres, M.S.

Changes in Iron and Manganese Concentrations in C&DD Leachate with Recirculation

As stated in the previous article in this series, the “Introduction to the Effects of Leachate Recirculation Series”, leachate data was compiled and analyzed using time series graphs and statistical trend testing. The time series graphs allow for a visual determination of trends. However, because there is significant variation in the data due to both natural variation and anomalous data points, visually assessing the trends can sometimes be difficult and subjective. The statistical trend testing using two methods, Sen’s Slope/Mann-Kendall slope estimator and Linear Regression, allowed for a more objective approach to determining trends. Read More
Tags: Civil Engineering, Environmental, Waste Management

01.31.17 | Michelle C. Torres, M.S.

Introduction to the Effects of Leachate Recirculation

The purpose of this article series is to explore the changes in leachate quality observed in three C&DD landfills recirculating leachate in Ohio and answer the question: Does leachate recirculation increase constituent concentrations? Read More
Tags: Civil Engineering, Environmental, Waste Management