Virus removal during simulated soil-aquifer treatment

Area of Science:

• Environmental Microbiology
• Water Treatment Technologies
• Groundwater Protection

Background:

• Soil-aquifer treatment (SAT) is a crucial process for purifying wastewater effluent.
• Understanding viral pathogen removal during SAT is vital for public health.
• Indigenous coliphage are often used as indicator organisms for viral contamination.

Purpose of the Study:

• To evaluate the removal efficiency of indigenous coliphage and seeded poliovirus type 1 during simulated SAT.
• To assess the influence of soil type and infiltration rate on viral removal.
• To investigate factors affecting coliphage retention and re-mobilization.

Main Methods:

• Simulated soil-aquifer treatment using 1-m soil columns (river sand and sandy loam).
• Transport of secondary effluent under unsaturated flow conditions.
• Varied infiltration rates, detention times, and simulated rainfall conditions.
• Inhibition of aerobic respiration to assess microbial involvement.

Main Results:

• Coliphage removal was consistently lower than poliovirus type 1 removal.
• Coliphage retention was significantly higher in sandy loam (93%) compared to sand (76%).
• Increased detention time enhanced coliphage attenuation from 70% to 99% in sand columns.
• Re-mobilization of coliphage occurred during simulated rainfall with low-ionic-strength water.
• Inhibition of aerobic respiration reduced coliphage attenuation efficiency.

Conclusions:

• Indigenous coliphage can serve as a conservative indicator for groundwater contamination by human viral pathogens.
• Soil type, detention time, and microbial activity significantly influence coliphage removal during SAT.
• Further research into the role of microorganisms in viral attenuation is warranted.