The Study Of Nitrophenol Wastewater Treatment Using Upflow Anaerobic Sludge Blanket (UASB)

In this thesis 3-NP and 2,6-DNP wastewaters are treated respectively by two upflow anaerobic sludge blanket (UASB). Degradation and transformation of nitrophenols are studied consequently. The effect of nitrophenol rate, input glucose concentrations and hydraulic retention time (HRT) to the degradation of nitrophenol and COD as well as the operation of UASB are investigated. At the mean time, the distribution of nitrophenol, aminophenol, COD, VFA and alkalinity along the different depth of UASB are investigated. The characteristics of anaerobic granules before and after experiment are also compared. The major conclusions follow below.(1) Throughout the study of 3-NP wastewater anaerobic degradation, input COD concentration and hydraulic retention time (HRT) are kept constant as 2500 mg/L and 26 h, respectively and the input 3-NP concentrations are increased from 20 mg/L to 250 mg/L. In the whole course of experiment 3-NP removal efficiencies are always more than 99%. 3-AP is found to be the major intermediate during the degradation of 3-NP. In the experiment of 3-NP degradation with different concentrations, on molar basis , about 60%～111.9% of 3-NP is recovered in the form of 3-AP, which detoxify 3-NP wastewater greatly. Due to input 3-NP concentrations increasing, COD removal decreases a little, but glucose removal is not affected and always high. The gas production increases from 7.95 L/d to11.04 L/d. The operation of UASB is stable and treatment of 3-NP wastewater using UASB is feasible.(2) Input glucose concentrations have obvious effect to the degradation of 3-NP and transformation of 3-AP, when input glucose concentrations decrease gradually. To have high 3-NP removal and transformation efficiencies, enough glucose must be kept in the input. In this paper 3-NP removal and rate of 3-AP conversion are always above 99% and 80%, respectively when input COD concentration is kept above 1000 mg/L. With the decreasing of input glucose concentrations, the output COD concentration is stable basically, but COD removals decrease gradually because 3-AP accounts for great in output COD. The gas production reduces gradually.(3) When input glucose and 3-NP concentration are kept constant and HRT is decreased from 26h to 12h gradually, 3-NP removal efficiencies are high and always above...