BIOLOGICAL FILTRATION - A COMPACT PROCESS FOR THE TREATMENT OF PULP AND PAPER-MILL WASTEWATERS - THE GUERIMAND-VOIRON PILOT EXPERIENCE - AVOIDING SECONDARY CLARIFIERS SAVES SPACE

As an alternative to conventional secondary treatment such as activate d sludge or an aerated lagoon, the biological aerated filter has demon strated its effectiveness over the last decade. The compactness of the Biofor(R) process makes it especially attractive where space is limit ed. It is well suited for treating low pollution loadings, SS < 200 mg /L and soluble COD < 400 mg/L. In 1990, a Biofor(R) pilot plant progra m was done at the Guerimand-Voiron fine paper mill in Voreppe (France) . Tests were run from 2.4 m3/m2/h to 5 m3/m2/h corresponding to averag e COD loadings of 6 to 11.44 kg COD/m3/d. At a loading of 4 m3/m2/h, t he following performance data were obtained: For clarified water, BOD5 < 115 mg/L, COD < 350 mg/L, SS < 50 mg/L; for treated effluent, BOD5 < 40 mg/L, COD < 150 mg/L, SS < 30 mg/L.