Geotextiles as biofilm filters in wastewater treatment

Cevat Yaman

doi:10.17918/etd-159

The goal of this dissertation was to develop a best management practice (BMP) treatment method applicable as appropriate to both point and non-point discharges, to produce a predictable effluent quality. A bench scale pilot plant study on the use of geotextile filters as biofilm attachment media in wastewater treatment was conducted at Drexel University. The goal was to produce an effluent of better quality than that required by secondary treatment standards by producing effluent having low concentrations of suspended solids, biochemical oxygen demand, and ammonia , while maintaining a hydraulic loading capacity in excess of that commonly used with conventional sand filters or septic system leaching fields. The project used packed columns containing alternating layers of gravel, sand and geotextile filters. The project was done in four phases. The first two phases screened candidate geotextile types. The next phase was an extended parametric study to determine the appropriate ranges of influential variables. They included the number of geotextile filter layers, the hydraulic loading rate and pattern, and provision for passive re-aeration. A confirmatory final phase was conducted using the best combination of material and operating method variables indicated by the parametric study. These were inserting two layers of continuous filament needle punched geotextile filters in a granular matrix of decreasing coarseness with depth, maintaining an unsaturated subgrade, and twice daily dose and drain application of primary treatment effluent at a net rate of 9.0 gal/day/ft2. The composite filter permeability of 0.9 cm/sec was sustained with little loss. TSS and BOD5 were reduced over 90% to less than 5 mg/l, thus meeting secondary treatment standards. Ammonia was reduced over 90%, meeting most special advanced surface or groundwater treatment standards and the effluent nitrate was at or below 10 mg/l, a commonly applied standard. The geotextile filter column outperformed the control column containing identical granular layers to geotextile filters in all respects. The results of this study show that geotextile biofilters can be applied to septic effluents and weather-generated non-point pollution sources. The second recommended usage of geotextile filters would be for stormwater treatment where storm sewer and sanitary sewer sewer are separate

Geotextiles as biofilm filters in wastewater treatment

Files and links (1)

Abstract

Metrics

Details

Geotextiles as biofilm filters in wastewater treatment

Files and links (1)

Abstract

Metrics

Details

Drexel University Social media