Project #1361

Quantitative Tools to Determine the Expected Performance of Wastewater Soil Treatment Units

Principal Investigator
Research Manager
Mr. Jeff C Moeller
Colorado School of Mines
Microbes & Pathogens
Biological Nutrient Removal (BNR)


This set of quantitative tools can be used to evaluate and design expected OWTS performance. Includes a Literature and Model Review (2009) and Guidance Manual, Toolkit User’s Guide, Excel spreadsheet tools (STUMOD and N-CALC), and supplemental visual information (2010). All can help users evaluate the treatment and fate of nitrogen, microbial pollutants (bacteria and virus), and organic wastewater contaminants and guide them to the most appropriate tool. Simple tools include look-up tables and cumulative frequency distributions. Nomographs enable insight into expected nitrogen removal based on the predicted output from STUMOD. Cumulative probability graphs illustrate modeling results in a risk-based framework. The spreadsheet tools, N-CALC and STUMOD, allow users to evaluate a range of STU operating conditions, soil hydraulics, and/or treatment parameters, and their relative influence on performance. Published by WERF. Online PDF. (2010)


As of February 2020, the web tool is no longer available.

Originally funded as WERF project DEC1R06abc.