Biological filters are wastewater treatment systems that contain a granular filling material, which form an active biological film that contribute to the biooxidation of impurities from the wastewater. Recent research in the field aimed to improve the classical treatment facilities with aerobic fixed film by using inexpensive and easily accessible materials as filterable loading. Experiments have been carried out on biological filters loaded with volcanic tuff, with a diameter between 20-100

more »

... supplied with municipal wastewater from primary settling. The biological filtration efficiency has been etablished throughout the continuous functioning of the experimental installation by physico-chemical water analysis. The analyzed indicators have been the ones stipulated by the legislation in force, namely: pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended matter (TS), total nitrogen (TN), total phosphorus (TP), etc. The analysed wastewater samples have been average samples. The treatment efficiency have been calculated in various hypotheses, depending on the: installation capacity, hydraulic loading, organic loading.