Virus movement in soil columns flooded with secondary sewage effluent

Area of Science:

• Environmental Microbiology
• Water Quality Engineering
• Soil Science

Background:

• Groundwater recharge with secondary sewage effluent is a common practice.
• Polio virus type 1 (LSc) is a common contaminant in sewage effluent.
• Understanding virus transport in soil is crucial for water safety.

Purpose of the Study:

• To evaluate the removal efficiency of polio virus type 1 (LSc) by calcareous sand.
• To investigate factors affecting virus movement and adsorption in soil columns.
• To assess the impact of infiltration rate, flooding, and drying cycles on virus removal.

Main Methods:

• Secondary sewage effluent spiked with poliovirus was passed through 250 cm soil columns.
• Virus detection in effluent and drainage water using plaque assays.
• Experimental manipulation of infiltration rates, deionized water flushing, CaCl2 addition, and soil drying cycles.

Main Results:

• Viruses were not detected below the 160-cm level, with most adsorption in the top 5 cm.
• Infiltration rate did not significantly affect virus removal.
• Deionized water caused virus desorption, while CaCl2 addition and soil drying (especially 5 days) prevented it.

Conclusions:

• Calcareous sand demonstrates high potential for poliovirus removal in groundwater recharge systems.
• Soil drying cycles are critical for minimizing virus movement after sewage application.
• Optimized management of flooding and drying cycles can enhance the safety of water reuse.