In this series of lectures, we will learn when biodegradation can or cannot occur and what conditions are conducive to faster degradation.

In this series of lectures, we will focus on the principles of abiotic degradation and discuss how these processes support monitored natural attenuation. You will be learning about the key reactions and minerals that are involved in abiotic degradation. We will also be covering what methods are used to determine if abiotic degradation is relevant at a particular site, and the rates at which these reactions may be occurring

In these lectures, we will focus on the idea that storage of contaminants in geologic media as a potential natural attenuation mechanism. Under this scenario, certain contaminants diffuse in low permeability media such as silt, clay, and limestone and then eventually reenter the aquifer by a process called back diffusion. Like sorption, this process is not destructive, but attenuates a contaminant plume by sequestering some of the initial loading and then slowly releases it over long time scales. You will learn about diffusion vs. dispersion, see case studies in the lab and field, learn how to sample and model this process, and hear the latest research about degradation processes associated with matrix diffusion.

In this series of lectures, we will discuss how dilution is an attenuation process – sometimes. We start with the basics, and review groundwater flow and one of the “top ten things” that every hydrogeologist should know: the distinction between Darcy Velocity and Seepage Velocity. Next we give some examples of regulatory programs where dilution is considered an acceptable attenuation process. Then we present how dispersion and mixing in wells are dilution-related processes. Finally we show how the emerging field of mass flux/ mass discharge can be used to see if a contaminant plume is strong enough to impact water supply wells and/or streams, and to see where your plume ranks in the “Plume Magnitude Classification System.”

In this series of lectures, we will focus on several established and emerging methods for demonstrating that biological and other attenuation processes are occurring. We will start with an overview on lines of evidence for biological degradation processes, and then transition to newer molecular methods for identifying and quantifying biodegradation potential for a variety of compounds. Several of this week’s lectures also examine compound-specific isotope analysis, which has been emerging as a key resource for MNA studies. You will learn how stable isotope analyses can provide critical information on whether attenuation is occurring, the rate at which it is occurring, and even the pathway that is responsible.

In this series of lectures, we will discuss how you should perform the monitoring that is such an important part of monitored natural attenuation (after all, it’s right there in the title!). We start off with a discussion of how data are collected, including using newer high-resolution techniques, to help build a proper conceptual site model and support the selection of MNA as a remedy. Then we touch on how to design a long-term monitoring program to assess the performance of MNA. Methods for analyzing concentration trends and graphically presenting MNA data are also presented, along with a discussion of the potential sources of variability in monitoring data.

In this series of lectures, we talk about models and how they can be used to understand MNA. We first start with two key MNA questions: How Long? (will the plume get) and How Far? (how long until the site is clean). Then a review of analytical computer models, remediation timeframe models, the more complex but more powerful numerical models, and even a discussion of the “Fourth Paradigm: Big Data”.

This final series of lectures will cover a mélange of interesting MNA topicsl We start with the brand new ESTCP BIOPIC tool, then talk about the broad universe of MNA that extends to a lot of different contaminant classes. Then some new developments in the LNAPL world: Natural Source Zone Depletion, both with conventional methods and a new method based on thermal monitoring. Then we talk a little bit about low threat closures and transition assessments, and end up with a brief conversation with the three instructors. And then you are done!