Barr analyzed the capital-improvement and operational costs of enforcing existing and anticipated wastewater discharge rules from the Minnesota Pollution Control Agency. The objective was to estimate (1) the costs for average residential and commercial connections to upgrade their infrastructure to meet existing and future water-quality standards, and (2) the incremental changes the upgrades would create in the quality of receiving waters.
We analyzed a representative cross-section of 15 communities in ecoregions across Minnesota. Our methodology involved gathering data about water bodies, population changes, and treatment facilities; calculating the degree to which existing and proposed standards would reduce pollutants in effluent; and evaluating the treatment technologies needed to meet existing and proposed standards. We then estimated the costs of upgrading wastewater treatment facilities and stormwater systems to meet both sets of standards. The estimates considered existing sewer rates as a percentage of median household income, as well as the increase in rates that would result from upgrading systems to meet existing and future standards.
Barr’s team also researched programs that could fund facility upgrades, and estimated the cost reductions those sources could provide. In addition, we prepared two conceptual plans: one for meeting the effluent limits set by existing standards, and one for meeting the limits expected in future standards. We developed a report on the results and implications of the analysis, and made four presentations to the Minnesota state legislature.
Five types of pollutant standards were specifically identified for inclusion in this study by the legislature: total suspended solids, chloride, nutrients (phosphorus and nitrogen), nitrate and sulfate. The study also addressed total maximum daily load analyses, as well as the antidegradation and tiered aquatic-life use rules. Notable among our findings, 13 out of the 15 wastewater treatment facilities studied would require upgrades to meet effluent limits, with chloride standards driving the potential compliance costs in nine of the 13 municipalities. Municipalities facing these compliance costs would likely pursue less costly options, such as source control and centralized water-supply treatment to reduce chloride in wastewater effluent.