Well House Number 2 Summary

As taken from the report summary by Aquaterra Environmental Solutions, Inc., Aquaterra installed an air stripper owned by the Kansas Department of Health and Environment (KDHE) in a new concrete block well house to treat impacted water from Public Water Supply Well Number 2. The system design was in general accordance with Aquaterra’s proposal, and as agreed upon between KDHE, the City of Clearwater, and Aquaterra.

Water Supply Well Location

The City of Clearwater’s Public Water Supply Well Number 2 (PWS  Number 2) is located on the northwest corner of the intersection of Ross Avenue and North 4th Avenue. The PWS Number 2 well is adjacent to the city’s water tower and just south of the Aquatic Center. The well is impacted with tetrachloroethene (PCE) from an unknown source.

Historic monitoring of the wells in the vicinity of PWS Number 2 indicate the PCE concentration in PWS Number 2, during an operating mode, could rise to approximately 25 micrograms per liter (ug/l). The following table summarizes historical PCE concentrations in groundwater samples collected from PWS Number 2.

Groundwater Analytical Results, PWS Number 2

Date Sampled
PCE (ug/l)
Date Sampled
(PCE (ug/l)
August 18, 1985
4.3 January 11, 1996
0.5
October 10, 1985
8.1 September 14, 1998
Less than 0.5
January 23, 1989
76.5 March 12, 2004
2.5
March 20, 1989
58.7 April 20, 2005
1.8
March 18, 1991
14.1 January 10, 2007
2.2
September 1991
14.1 June 27, 2007
0.73

Tray Aerator Installation & Effectiveness

Because of this historical data, the City of Clearwater in coordination with the State of Kansas and Aquaterra, applied for a permit to install a tray aerator in PWS Number 2 to treat well water to remove PCE. The permit was approved and the tray aerator has been installed. Currently, levels of PCE in the well are less than Maximum Contaminant Levels allowed for potable water use.

However, the design of the tray aerator and the system surrounding it is based on PCE levels reaching two times the highest level in project monitor wells (25 parts per billion) for an influent concentration of 50 parts per billion. Copies of the design model for the particular model of tray aerator that is installed at PWS Number 2 show that a single tray system will reduce the PCE concentrations to less that 1 part per billion with a 50% factor of safety using the coldest inlet air conditions. Since the tray aerator system that was installed included three trays, the system will have a factor of safety of two for the additional trays plus an additional factor of safety due to the design assumptions.

In addition, the treated water will be pumped into the water supply system in the morning, when demand is highest, the treated water will be further blended with water from the water tower, further protecting the quality of the drinking water supply. Initial testing of the system was conducted on June 27, 2007. PWS Number 2 was operated for approximately 1.5 hours before influent and effluent water samples were collected by Aquaterra and KDHE.

Treatment System Analytical Results, PSW Number 2

Laboratory reporting limit indicated in parentheses for non-detected results.
Date Sampled
Influent PCE (ug/l)
Effluent PCE (ug/l)
June 27, 2007 (Aquaterra)
Not Detected (1)
Not Detected (1)
June 27, 2007 (KDHE)
0.73 Not Detected

Questions

This information as presented is only a portion of the construction documentation report on the PWS Number 2 Air Stripping Treatment System Installation as prepared by Patrick Goeke, P.E., Senior Project Manager for Aquaterra. This information is presented to you as a part of the justification for the work done on PWS Number 2 and the initial results that have been achieved. If you have any questions, please call City Hall at 620-584-2311.