Science Inventory

Virulo

Citation:

Virulo. U.S. Environmental Protection Agency, Washington, DC.

Impact/Purpose:

Information

Description:

Virulo is a probabilistic model for predicting virus attenuation. Monte Carlo methods are used to generate ensemble simulations of virus attenuation due to physical, biological, and chemical factors. The model generates a probability of failure to achieve a chosen degree of attenuation. Data are tabulated from related studies to develop probability density functions for input parameters, and Virulo utilizes a database of soil hydraulic parameters based on the 12 USDA soil categories. Regulators can use the model based on limited information such as boring logs, climate data, and soil survey reports for a particular site of interest. The model may be most useful as a tool to aid in siting new septic systems. Virulo is extensible in the sense that probability density functions of parameters can be modified as future studies refine the uncertainty, and the lightweight object-oriented design of the computer model (implemented in Java) will facilitate reuse with modified classes, and implementation in a geographic information system.

Record Details:

Record Type:DOCUMENT( PUBLISHED REPORT/ REPORT)

Record Released:10/15/2009

Record Last Revised:08/10/2012

OMB Category:Other

Record ID: 215008

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Keywords:

Monte Carlo modeling, probabilistic tool, log attenuation, Safe Drinking Water Act, Ground Water Rule,

Model Keywords:

Safe Drinking Water Act (SDWA), Clean Water Act (CWA), Location, Stochastic, providing a distribution of values for key model outputs, Primarily lumped representation, Predicts for static conditions, Water (e.g., surface water, ground water), Ground (e.g., soil, sediment), Mobile Source (e.g., automobiles, trains, ships, airplanes), Area Source (e.g., spray, fertilizer, lagoon, holding area), Point Source (e.g., tank, spill, stack, discharge pipe), Biological (e.g., microbial), Resource Conservation and Recovery Act (RCRA),

Model Detail:

Model Evaluation :Virulo follows EPA Quality Assurance guidelines. The following references describe the model and its use:

Faulkner BR, Lyon WG, Khan FA, Chattopadhyay S. 2003. Modeling leaching of viruses by the Monte Carlo method. Water Research 37:4719-29.

Faulkner BR, Lyon WG, Khan FA, Chattopadhyay S. 2002. Predicting Attenuation of Viruses During Percolation in Soils: 1. Probabilistic Model. US Environmental Protection Agency Report EPA/600/R-02/051a, August 2002, 33 pp.

Lyon WG, Faulkner BR, Khan FA, Chattopadhyay S, Cruz JB. 2002. Predicting Attenuation of Viruses During Percolation in Soils: 2. User’s Guide to the Virulo 1.0 Computer Model. US Environmental Protection Agency Report EPA/600/R-02/051b, August 2002, 17 pp.

Model URL :http://www.epa.gov/nrmrl/gwerd/csmos/models/virulo.html

Model Guidance Documents :Virulo User's Guide

Model Download Information :Download from the links at:
http://www.epa.gov/nrmrl/gwerd/csmos/models/virulo.html

modelcontactinfo :Agency Contact:
Bart Faulkner
ORD/NRMRL/GWERD/ESPB
USEPA
faulkner.bart@epa.gov
580-436-8530

Model Inputs :Inputs are provided in an included database, but user can modify unsaturated zone van Genuchten parameters, soil bulk density, mean soil particle radius, dispersivity, inactivation rate coefficients, mass transfer coefficients, effective virus radius, equilibrium partitioning coefficient

Model Outputs :Histogram of log attenuation, probability of exceedance of a specified target attenuation level

otheruserdocs :Theoretical background document

Model Computer Requirements:

Model Operating Systems Needs :Windows (tested through XP Pro), Apple Mac OS-X, Linux, Solaris

Model Hardware Needs :At least 100 MHz speed and at least 32 MB RAM

other_req :Java Virtual Machine (can be included in installation if needed)