ABSTRACT
In this paper, the biological-aerated filter (BAF) was employed to treat the wastewater containing terephthalic acid (TA). Factors that affected the efficiency of TA and CODCr removal were evaluated experimetally, including pH, hydraulic loading, hydraulic retention time (HRT) and TA volume loading. At pH 7-8, hydraulic loading rate 0.067-0.48 m3/(m2 h), HRT more than 3.5h and TA loading 0.04-0.15g/(m3 d), the TA and CODCr removal efficiency was more than 93% and 87%, respectively. The mathematical model of matrix (TA) was obtained by Monod's relation and the experimental parameters of the model were 1.972 g/(m2d) and 9.782 mg/L.
Subject(s)
Bacteria, Anaerobic/metabolism , Membranes, Artificial , Phthalic Acids/metabolism , Ultrafiltration/methods , Wastewater/microbiology , Water Pollutants/metabolism , Water Purification/methods , Air , Feasibility Studies , Phthalic Acids/isolation & purification , Waste Disposal, Fluid/methods , Wastewater/analysis , Water/chemistry , Water Pollutants/isolation & purificationABSTRACT
The radiation-induced degradation process of diuron and change of toxicity by gamma-irradiation were investigated. The contribution to diuron degradation by the radicals is in the order of: *OH > e(aq)(-) > *H. The quantum efficiency ratios of *OH, e(aq)(-) and *H for the degradation of diuron are calculated as 3 : 1 : 2. e(aq)(-) and *H could reduce diuron and its degradation product by loss of the chlorine atoms and the addition reaction. Both the shift and alkaline substitute mutations firstly increase and then decrease with the increase of irradiation time. But, the sample only shows mutagenic potential in Ames assay (TA100 strain) when 22.2 min is selected as the irradiation time. The acute toxicity firstly decreases and then increases with the increase of irradiation time and the more toxic substances are produced.