Field Facilities

In support of the Small Flows Program at the Colorado School of Mines, the Mines Park Test Site was established to enable controlled field research to (1) determine the treatment mechanisms that can be exploited to purify water by removal of pollutants, chemicals, and microbes of concern, (2) quantify the design and performance relationships for different onsite treatment unit operations, and (3) develop mathematical relationships and models for aiding system selection and design.  The treatment methods and technologies being investigated at the Test Site include an array of bioreactors, biofilters, membrane units, constructed wetlands, soil infiltration cells, and drip dispersal networks.  Monitoring and process control methods are also being studied.  To date, more than $2 million dollars have been invested in infrastructure and research and educational activities.
Ongoing topics of research at the Mines Park Test Site include:

Mines Park Test Site Description

The Mines Park Test Site was established in 2001 and is located on the CSM campus adjacent to the Mines Park student-housing complex near the corner of Highway 6 and 19th Street in the City of Golden, Colorado (Fig FF1). At the site, wastewater from a multifamily housing complex is intercepted and managed onsite using pilot-scale unit operations and in-ground test cells with associated sensors and monitoring devices (Fig FF2). The site is in a natural undeveloped state typical of the Rocky Mountain Front Range foothills located at 1820 to 1823 m above mean sea level with an easterly slope of approximately 5 to 7%. Typical winter temperatures range between 0.5 and 3.5 oC with average summer temperatures ranging between 16.6 and 25.8 degrees C. The average annual precipitation is approximately 45 cm.

The soils at the Mines Park site are described as Ascalon sandy loam (fine-loamy, mixed, mesic Aridic Arugiustolls) (USDA 1983) with the parent materials generally derived from igneous and metamorphic rocks of the mountains and sedimentary rocks of the foothills. During the site inspection completed by CSM, the soil profile was assessed through two backhoe test pits and nine soil borings to 8 m deep with soil samples collected every 60 cm (Fig FF3). The particle size distribution, determined by sieve and hydrometer analysis, revealed 59 to 69% sand, 17 to 13% silt, and 24 to 18% clay (dry wt. %) (Lowe and Siegrist, 2002 pdf).  Total organic matter ranged from 1.0% (dry wt. %) at 60 cm to 0.5% at 2.6 m below ground surface (bgs). The soil moisture content ranged from 6.4 and 7.1% (dry wt. %). Cation exchange capacity ranged between 11.3 and 15.0 meq/100 g dry soil and was relatively constant across the site. The soil pH was 6.4.

During the site inspection, no saturated conditions, either perched or continuous, were observed. Mottling indicative of high groundwater was observed in three of the nine borings at depths greater than 1.5-m bgs. Water levels in shallow groundwater observation wells installed at the site typically range from 3 to 5 m bgs. Percolation tests were conducted at four locations using 1-m deep, 10-cm diameter holes yielding an average percolation rate of 6.1 min/cm. In addition, baseline infiltration rates have been measured within each of the in situ test cells using clean water and a constant head permeameter (2.5 cm head at the soil surface) prior to wastewater application. Over 60 test cells have been installed as described below in the Natural System Research.  Based on these tests, the infiltration rate of the soil at approximately 0.5 – 1 m bgs is relatively consistent across the site (Fig FF4) ranging between ~40 and 63 cm/d.


FF4 – Summary of constant head infiltration rates across the Mines Park Test Site prior to wastewater application to soil test cells.




Bi monthly samples have been collected from the Mines Park Test Site wastewater source for over 5 years. The septic tank effluent (STE) composition is generally characterized as:  ph 7.3, alkalinity 255 mg CaCO3/L, cBOD5 162 mg/L, TSS 43 mg/L, total nitrogen 60 mg-N/L, ammonia 55 mg-N/L, total phosphorus 8 mg-P/L, and fecal coliform 1 x 105 cfu/100 ml. Further microbial analysis suggests the STE is primarily dominated by two Phyla; Proteobacteria and Bacteroidetes with the genus Arcobacter (Campylobacteraceae family) the dominant phylotype detected (Fig FF5). Raw wastewater sampling suggests little variation between the raw wastewater and STE in the carbon, solids, nutrient, and fecal coliform bacteria concentrations. Specific results and additional information are incorporated within individual experimental publications.


FF5 – Bacterial phylogenetic distribution for conventional STE located at the Mines Park Test Site.