1. BIOSCREEN AND BIOCHLOR Natural Attenuation Modeling Tools

2. BIOSCREEN
easy-to-use screening model that simulates remediation by natural attenuation (RNA) of dissolved hydrocarbons at petroleum fuel release sites
programmed in the Microsoft Excel spreadsheet
based on the Domenico analytical solute transport model, has the ability to simulate advection, dispersion, adsorption, and biological decay (aerobic and anaerobic)

3. BIOSCREEN Includes three different model types:
1) Solute transport without decay,
2) Solute transport with biodegradation modeled as a first-order decay process (simple, lumped-parameter approach),
3) Solute transport with biodegradation modeled as an "instantaneous" biodegradation reaction (approach used by BIOPLUME models)

4. Intended uses for BIOSCREEN
BIOSCREEN attempts to answer the questions:
How far will a dissolved BTEX plume extend if no engineered controls or source area reduction measures are implemented?
How long will the plume persist until natural attenuation processes cause it to dissipate?
BIOSCREEN is intended to be used in two ways:
1. As a screening-level model to determine if RNA is feasible at a fuel hydrocarbon site.
2. As the primary RNA groundwater model at smaller sites.

5. Limitations of BIOSCREEN
As an analytical model, BIOSCREEN assumes simple ground-water flow conditions.
As a screening tool, BIOSCREEN only approximates more complicated processes that occur in the field.

6. BIOSCREEN input screen

7. BIOCHLOR
easy-to-use screening model that simulates remediation by natural attenuation (RNA) of dissolved solvents at chlorinated solvent release sites
programmed in the Microsoft Excel spreadsheet
based on the Domenico analytical solute transport model, has the ability to simulate 1-D advection, 3-D dispersion, linear adsorption, and biotransformation via reductive dechlorination

8. BIOCHLOR reductive dechlorination assumed anaerobic
biodegradation follows a sequential first-order decay process
includes three different model types:
solute transport without decay,
solute transport with biotransformation (sequential first-order decay process),
solute transport with biotransformation (sequential first-order decay process with two different reaction zones)

9. Intended uses for BIOCHLOR
BIOCHLOR attempts to answer the question: How far will a dissolved chlorinated solvent plume extend if no engineered controls or source area reduction measures are implemented?
BIOCHLOR is intended to be used in two ways:
1. As a screening-level model to determine if RNA is feasible at a chlorinated solvent site.
2. As an RNA ground-water model to address selected chlorinated solvent problems

10. Limitations of BIOCHLOR
As an analytical model, BIOCHLOR assumes simple ground-water flow conditions.
As a screening tool, BIOCHLOR assumes uniform hydrogeologic and environmental conditions over the entire model area.
BIOCHLOR is primarily designed for simulating the sequential reductive dechlorination of chlorinated ethanes and ethenes.

11. BIOCHLOR input screen