The use of laboratory sand, soil and crushed-glass filter columns for polishing domestic-strength synthetic wastewater that has undergone secondary treatment.
The aim of this study was to examine the performance of intermittently loaded, 150 mm-diameter stratified filter columns of 2 depths (0.65 and 0.375 m) comprising different media--sand, crushed glass and soil--in polishing the effluent from a laboratory horizontal flow biofilm reactor (HFBR) treating synthetic domestic-strength wastewater. The HFBR has been successfully used to remove organic carbon and ammonium-nitrogen (NH4-N) from domestic wastewater. In this treatment method, wastewater is allowed to flow over and back along a stack of polyvinyl chloride (PVC) sheets. Biofilms on the sheets reduce organic carbon, suspended matter, and nutrients in the wastewater, but to achieve the quality of a septic tank system, additional treatment is required. In all filters, at a hydraulic loading rate of 100 L m(-2) d(-1), 40-65% of chemical oxygen demand (COD) and practically 100% of total suspended solids (TSS) were removed, nitrification was complete, and bacterial numbers were reduced by over 80%, with best removals achieved in the soil filters (93%). Soil polishing filters with the depth of 0.65 m performed best in terms of organic carbon, total nitrogen (Tot-N) and bacterial removal. Data from this preliminary study are useful in the design of treatment systems to polish secondary wastewaters with similar water quality characteristics.
Healy
M G
MG
Civil Engineering, National University of Ireland, Galway, Ireland. mark.healy@nuigalway.ie
Burke
P
P
Rodgers
M
M
D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology; D005374:Filtration; D005898:Glass / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D018508:Water Purification / Q000379:methods
D012987:Soil; D010758:Phosphorus; D012822:Silicon Dioxide; D009584:Nitrogen