The effects on degrading 3-nitrophenol (3-NP) with sodium acetate as co-substrate under the conditions of laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was investigated at an operating temperature of 35±1°C in this study. The results showed that the optimum influent 3-NP concentration was 71.6mg/L when keeping influent COD concentration for 2500 mg/L and hydraulic retention time (HRT) for 30 h. At the stage of reducing influent COD concentration, all of the 3-NP removal rates were more than 95%; while the conversion rate of 3-aminophenol (3-AP) decreased from 61.4% to 0.2%. Meanwhile, the reduction of HRT also had significantly effects on the treatment effect of 3-NP. With the decreases of HRT, COD removal dropped to 49.7% from 82.7%.

Effect of cationic polymer on granulation and COD removal efficiency in lab scale UASB reactors was examined, treating low-strength wastewater (COD 300-500mg l-1) at room temperature. It was shown that cationic polymer was more effective for enhancing sludge granulation and COD removal efficiency as compared to the control experiment (without additives). After day 166 of operation, the amount of granules size above 0.5mm accounted for 32.1% of total sludge, higher than that of control experiment (19.3%). At 1.03 kg COD m-3 d-1 of OLR and 9.8 h of HRT, the effluent VFA had a maximum value of 168mg l-1 and 240mg l-1 in Reactor A and B respectively. The polymer-amended reactor took 36days to receive 1.44 kg COD m-3 d-1 of OLR at the 7.8 h of HRT, shorter than the control reactor (54days). The two reactors obtained above 80% in COD removal efficiency. It is shown that UASB reactor can also achieve higher COD removal treating low strength wastewater at room temperature.

Characteristics of anaerobic granules before and after acclimation were studied using glucose as co-substrate. Removal efficiencies of 2,6-dinitrophenol (2,6-DNP) using two different co-substrates were investigated in two lab-scale UASB reactors. Granular sludge acclimatized to the wastewater containing 2,6-DNP through 3 months. After acclimation, SEM pictures of the granular biomass showed that Filamentous bacteria were the predominant bacteria on the surface of granules. Throughout the study of 2,6-DNP anaerobic degradation with different co-substrates, influent COD concentration was kept constant as about 2500 mg l-1. Maximum 2,6-DNP concentration was 170.0 mg l-1 and 2,6-DNP removal efficiencies were always more than 98.0% using glucose as co-substrate, keeping hydraulic retention time (HRT) as 35 h. When using sodium acetate as co-substrate and keeping HRT as 30 h, maximum 2,6-DNP concentration was up to 189.5 mg l-1 and over 99.2% 2,6-DNP removal efficiencies could be obtained.

The degradation kinetics of 2,4-dinitrophenol (2,4-DNP) and 2,6-dinitrophenol (2,6-DNP) were investigated in this paper. The degradation kinetics experiments were conducted in sequencing batch reactor (SBR) and the degradation model was analyzed by nonlinear regression to estimate parameters including the degradation rate Kmax, half saturation constant KSand the inhibition constant KIin the Andrews inhibition equation. The degradation inhibition in the condition of 2,4-DNP as solo substrate is more serious than that of the situation with glucose as co-substrate and Kmaxdecreases with the increase of inflow 2,4-DNP concentration. As for 2,6-DNP, Kmaxgets maximum value is 0.019 mg/(mgSS×d) at the inflow concentration is 20mg/L. KSincreases with the increasing of inflow 2,6-DNP concentration but there is no regularity for KI.

The composting of sewage sludge and maize straw was investigated in forced-aeration composting systems at aeration rates of 0.28, 0.56 and 0.83 l min-1kg-1organic matter, corresponding to pile A, pile B and pile C. The composting temperature in three piles met the hygienic safety criterion, and final electrical conductivity did not exceed the limit value of 3000 μS cm-1. The final NH4+-N content in pile C exceeded the limit value of 400 mg kg-1. The final NO3--N content, cation exchange capacity and germination index in pile B were superior to those in pile A and pile C.