Performance of innovative textile biofilters for domestic wastewater treatment

Abstract

Two types of geotextile, TS 50 and TC/PP 300, were investigated as experimental filters. The raw wastewater, pre-treated in a septic tank, was intermittently dosed and filtered under hydrostatic pressure. At the beginning, the filter reactor comprised nine filters made of geotextiles (of three types: TS 10, TS 50 and TC/PP 300). At the end of the start-up period the TS 10 filters were removed due to their high outflow instability. After four months of working, the hydraulic capacities of the remaining filters were: 3.23 cm ³/cm ²/d for TS 50 and 4.14 cm ³/cm ²/d for TC/PP 300. The efficiencies of COD and BOD ₅ removal were similar for both types of geotextile (COD: 64%, BOD ₅: 80%). A small but statistically significant difference between ammonium nitrogen removal was observed (40% for TS 50 and 35% for TC/PP 300), most probably due to their different structure. Biological removal of P _tot was relatively poor and similar for both geotextile types. The mean concentration of matter accumulated on the geotextiles was over one order of magnitude higher than conventional activated sludge concentrations. During the last weeks of the experiments the values of basic pollution indicators in the effluent were lower than the maximum permissible values (according to Polish law).

Keywords:

• wastewater treatment
• textile filter
• hydraulic capacity
• organic compounds
• nutrients

Acknowledgements

The authors gratefully acknowledge the funding of this investigation by the Ministry of Science and Higher Education (grant No. N207 070 31/3402).