Infiltration basins for  groundwater recharge of treated wastewater in Glendale, Arizona.

Pharmaceuticals and personal care products (PPCPs) in the environment have recently become a concern to both scientists and the public because of toxicological effects on aquatic organisms and the possibility of unknown effects on humans. Wastewater treatment plants (WWTPs) fail to remove PPCPs completely, causing the micropollutants to be discharged with the plants’ effluent into the environment, where they contaminate raw drinking water sources. A potential method for removing PPCPs from WWTP effluent is soil aquifer treatment (SAT), a technique already employed in arid regions, as shown in Figure 1. SAT is a method of water recycling which involves passing impacted water through soil, exposing contaminants to degradation processes.

WWTP effluent samples are collected and used for inoculating the lab columns.

Preliminary studies have simulated SAT conditions in the laboratory using bench-scale sand columns inoculated with collected WWTP effluent (Figure 2) and have shown promising results for the use of this technique for biological removal of PPCPs from water. The entire laboratory column configuration is shown in Figure 3. The proposed research will go beyond these previous engineering studies by delving into the microbiology of the processes responsible for removing the PPCPs. A laboratory column will be supplied with media containing a suite of 14 PPCPs until the resident biofilms achieve a pseudo-steady state.

Media is fed to upflow laboratory columns by a peristaltic pump.

At this point, the column will be sacrificed and aseptically dismantled for microbial community analysis of the biofilm growing on the column’s sand substratum. DNA extracted from this column will be used for 454 massively parallel pyrosequencing. A soil sample from an actual SAT site in the southwestern U.S. will be obtained and will also undergo the same DNA extraction and sequencing as the lab column sample. The hundreds of thousands of sequences generated from this procedure will be analyzed with specially designed software to construct community profiles for the samples. This information will allow comparison of the communities in the two samples and will provide context for previous and future PPCP biodegradation research.