Evaluation of Soil Aquifer Treatment in a Lab Scale Soil Column Experiment

Soil aquifer treatment (SAT) during managed aquifer recharge has been studied as a method of providing additional environmental barriers to pathogens and contaminants in indirect potable reuse (IPR) applications. A soil column study was conducted by Hampton Roads Sanitation District in order to evaluate the effectiveness of SAT, as a component of its IPR project involving the replenishment of the Potomac Aquifer System (PAS), in providing a sustainable source of drinking water. Four packed soil columns were constructed with sand from the PAS and were designed to simulate the travel time of 3 days and 30 days. The tests conducted aimed at evaluating pathogen removal (MS2, E. coli and Cryptosporidium oocysts); evaluating attenuation of regulated (nitrate, nitrite, bromate, trihalomethane (THM), haloacetic acids (HAA), organic carbon) and unregulated contaminants of concern that affect drinking water quality. Effective pathogen removal was observed with 6 to 7-log removals of MS2 and E. coli and 3 to 5-log removals of microbeads, used as a surrogate for Cryptosporidium. Removal across 3 day columns was comparable to 30-day columns but the potential to achieve higher removal with longer retention time was acknowledged. Nitrate, bromate, THMs and HAAs were completely reduced in 30-day columns. Total organic carbon was removed at 25 – 35% in all four columns. Seven out of the 106 contaminants of emerging concern (CEC) tested were consistently detected in the column feed and effluent at concentrations greater than 100 ng/L; some compounds showed potential for removal while no conclusive results were drawn for the remaining compounds.

Name thesis:degree_name

MS

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Environmental Engineering

Department dc:contributor.department

Environmental Science and Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2018

Author dc:creator

• Pradhan, Prarthana

Chairs dc:contributor.committeechair

• Bott, Charles B.
• Widdowson, Mark A.

Committee member dc:contributor.committeemember

• Dietrich, Andrea M.

• soil aquifer treatment
• soil columns
• indirect potable reuse
• managed aquifer recharge

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:17997

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/98749