About

Dr. Sara Heger is a researcher and instructor in the Onsite Sewage Treatment Program within the Water Resources Center at the University of Minnesota. She has been providing education and technical assistance since 1999 to homeowners, small communities, onsite professionals, and local units of government regarding onsite wastewater treatment. She coordinates the research program at the University of Minnesota and serves as the principal investigator on projects evaluating wastewater treatment and rest areas, as well as developing training related to the land application of industrial wastewater. Sara Heger is on the faculty of the Water Resources Science program, teaching courses such as Sustainable Waste Management Engineering. She presents at many local and national training events concerning the design, installation, and management of septic systems and related research. She is the president of the National Onsite Wastewater Recycling Association (NOWRA) and serves on the NSF International Committee on Wastewater Treatment Systems. Additionally, she is the chair of the Minnesota State Advisory Committee on Decentralized Systems. Her educational background includes a BS in Biosystems & Agricultural Engineering and a PhD in Water Resource Science, both from the University of Minnesota.

Research topics

• Environmental engineering
• Environmental protection
• Engineering
• Ecology
• Environmental science
• Chemistry

Selected publications

• Examining Chloride in an Agricultural Watershed Using a Chloride Balance Model

  Environmental and Engineering Geoscience · 2025-05-01 · 1 citations

  article

  ABSTRACT Elevated chloride levels in lakes, rivers, streams, and groundwater are a concern in many snowbelt states, particularly in urban areas where deicing and anti-icing salt are major sources of chloride pollution. In agricultural and mixed land use watersheds, other chloride sources such as fertilizer, water softening, manure, wastewater discharge, and industry may be more substantial sources of chloride pollution. A chloride budget was conducted for Sand Creek watershed, a chloride-impaired, agricultural watershed in southern Minnesota, with the purpose of developing a model for watersheds with limited data and characterizing important chloride sources in less urban settings. Annual chloride mass contributions were estimated for major point and nonpoint sources from June 2013 to May 2019, including wastewater treatment plants, industry, deicing salt, potash fertilizer, livestock, and septic systems using various permitting data, monitoring data, land use data, census data, and other records. The estimated annual chloride budget was used in conjunction with a water balance model to estimate monthly and annual loads and flow-weighted mean monthly concentrations. Results from the chloride balance model show good agreement with more detailed models for the watershed. Road salt, fertilizer use, wastewater treatment plant discharge, and manure application were estimated to be the largest chloride sources that impacted a number of creeks in the Sand Creek watershed. Results from the chloride balance model for the watershed suggest significant chloride retention in the watershed across seasons and that chloride loading in the stream is more sensitive to major runoff events than timing of application from individual sources.

  PublisherDOI

• Emerging investigator series: are we undervaluing septage? Rethinking septage management for nutrient recovery and environmental protection

  Environmental Science Water Research & Technology · 2025-01-01 · 1 citations

  articleOpen access

  Septage is an untapped waste stream that could be utilized for recovery of beneficial nutrients, energy, and water.

  PublisherOA PDFDOI

• Evaluation of Biochar and Iron as Alternative Materials to Improve Performance of Septic Systems—Part 1. Material Selection and Batch Tests

  Water Environment Research · 2025-11-26

  articleOpen access

  ABSTRACT The benefits of incorporating biochar and iron as alternative materials to improve septic effluent quality were assessed and compared to C33 sand, a traditional material used to construct septic system soil treatment areas. This study used sequential batch tests to investigate pollution reduction performance of C33 sand, eight types of biochar, and three types of iron with various dosages to identify and optimize operational parameters. Pseudo‐first‐order and pseudo‐second‐order kinetics models were used to simulate temporal performance of wastewater treatment and identify likely mechanisms driving improvements in septic effluent quality. Softwood pine (SP) biochar was most effective at reducing biological oxygen demand (BOD), total nitrogen (TN), and fecal coliform (FC) in septic effluent, while treatment with iron‐enhanced‐sand (IES) produced the highest removal efficiency for total suspended solids (TSS) (> 80%) and total phosphorus (TP) (> 95%) among substrates tested. Experimentation revealed dosages that achieved optimal pollutant removal from 50‐mL septic effluent were 5‐g C33 sand, 1‐g SP, or 2‐g IES. Kinetics study showed that the pseudo‐second‐order model generally described the adsorption performance better than the pseudo‐first‐order model regardless of materials (average R 2 value > 0.95). Furthermore, the pseudo‐second‐order model simulated adsorption capability (mg g −1 ) at equilibrium status with a lower percent error when compared to the pseudo‐first‐order model results. Based on these results, incorporation of SP and IES as alternative materials can achieve higher contaminant removal efficiency and produce cleaner septic effluent, thereby benefiting the environment.

  PublisherOA PDFDOI

• Evaluation of chloride contributions from major point and nonpoint sources in a northern U.S. state

  The Science of The Total Environment · 2020 · 51 citations

  • Environmental science
  • Environmental engineering
  • Environmental protection
  PublisherDOI

• Investigating Wastewater Reuse at MnDOT Truck Stations

  University of Minnesota Digital Conservancy (University of Minnesota) · 2019-05-01 · 1 citations

  articleOpen access1st authorCorresponding

  The University of Minnesota (UMN) and the Minnesota Department of Transportation (MnDOT) conducted a study to determine whether implementing a wastewater reuse program would be a feasible option for MnDOT-owned truck washing stations. MnDOT has 137 truck stations in the state, where trucks are frequently washed to remove road salt build-up. MnDOT recognized an opportunity to potentially reuse the wastewater for appropriate greywater uses and recapture the salt for road use. Sampling was done to assess the wastewater contaminants in truck wash water at 11 truck-washing stations in Minnesota. Then technologies suited to removing organics and total suspended solids (TSS) but not chlorides were reviewed. The recommendation is that either a recirculating sand filter (RSF) or a membrane bioreactor (MBR) would be feasible technologies to use for this purpose. Using the MnDOT truck station in Arden Hills, Minnesota, an economic evaluation was done. Both systems could be used to effectively treat wastewater and produce brine for reuse, but the most economical solution for MnDOT would be to invest in a MBR. Compared with a RSF, an MBR is one-third less expensive over time, primarily due to low material and installation cost as well as a lower annual maintenance costs.

  Publisher

• Septic System Evaluation at MnDOT Rest Stops, Truck Stations and Weigh Scales

  University of Minnesota Digital Conservancy (University of Minnesota) · 2016-01-01 · 1 citations

  articleOpen access1st authorCorresponding

  The University of Minnesota (UM) and the Minnesota Department of Transportation (MnDOT) performed a unique evaluation of the 52 existing subsurface sewage treatment systems at safety rest areas (SRA) travel information centers, truck stations and weigh scales at MnDOT facilities across Minnesota. This three year partnership brought together the septic expertise of the UM with the MnDOT wastewater unit’s agency and site knowledge. The goal of the assessments was to evaluate risk and provide a risk analysis ranking system. The project began with an extensive record search where many documents were digitized and a database of information created. The next step was development of a draft assessment protocol. This draft protocol was pilot tested on five systems and refined based on those experiences. The full assessment included a preliminary review of the site, a facility assessment, effluent sampling, septic tank inspections, evaluation of advanced treatment units when present and an assessment of the soil treatment system. The information from the assessment was used to develop a risk ranking of all systems. The risk assessment created can be used for planning purposes to prioritize capital upgrades, but only if a sustainable process is created and incorporated into the day to day workload.

  Publisher

• Evaluation of Four Milk House Wastewater Treatment Systems in Minnesota

  University of Minnesota Digital Conservancy (University of Minnesota) · 2015-08-01

  dissertationOpen access1st authorCorresponding

  University of Minnesota Ph.D. dissertation. August 2015. Major: Veterinary Medicine. Advisor: Ed Nater. 1 computer file (PDF); viii, 102 pages.

  Publisher

• Aerobic and Media Filter Treatment Systems for Milk House Wastewater on Small Dairy Operations

  Applied Engineering in Agriculture · 2010-01-01 · 2 citations

  article1st authorCorresponding

  Four different aerobic treatment systems were installed downstream of one or more septic tanks to treat milk house wastewater on nine dairy farms with between 41 and 130 cows. Seven farms had pipeline milking systems, one farm had a flat parlor and one had a milking parlor where parlor wash water entered the milk house wastewater treatment system. Two Biomicrobics FAST systems, two NCS Nibbler systems, three Pirana units, and two Reactor Dynamics, Inc. DYNO2 units were installed. System performance was monitored over 1 to 2 years by measuring water use and collecting wastewater samples.

  PublisherDOI

• Choosing an Alternative Septic System for a Homesite with a High Water Table

  University of Minnesota Digital Conservancy (University of Minnesota) · 2000-01-01 · 1 citations

  articleOpen access
  Publisher

Frequent coauthors

• Alycia Overbo

  4 shared

• Dave Gustafson

  2 shared

• John S. Gulliver

  Saint Anthony College of Nursing

  2 shared

• D. Brian Wheeler

  1 shared

• D. R. Schmidt

  1 shared

• K. A. Janni

  1 shared

• Barbara W. Liukkonen

  1 shared

• Melissa Collins Rutter

  1 shared

Awards & honors

• 2013-2018 NOWRA Education Committee Chair Appreciate Award
• 2003, 2006, 2010 Minnesota Onsite Wastewater Association Out…