Center of Exact and Technological Sciences, Western Paraná State University (UNIOESTE), Universitária Street, 2069, 85819-210, Cascavel, PR, Brazil.
Center of Exact and Technological Sciences, Western Paraná State University (UNIOESTE), Universitária Street, 2069, 85819-210, Cascavel, PR, Brazil.
J Environ Manage. 2022 Feb 1;303:114162. doi: 10.1016/j.jenvman.2021.114162. Epub 2021 Nov 30.
The aim of this work was to assess the nitrogen removal from slaughterhouse wastewater in an anaerobic-anoxic-aerobic combined reactor, evaluating the integrated effect of recirculation rate and hydraulic retention time. The recirculation of the liquid phase from the aerobic zone to the anoxic zone was applied to promote the denitrification through the use of endogenous electron donors. Three recirculation rates (R: 0.5, 1 and 2) and three hydraulic retention times (14, 11 and 8 h) were applied. The operation of the reactor was divided into 3 steps (I, II, and III) according to the factors evaluated (recirculation rate and HRT), to achieve operational conditions that would allow satisfactory performance in the different compartments of the reactor. During the experiment the reactor was fed with average total nitrogen (TN) and chemical oxygen demand (COD) of 65 mg L and 580 mg L, respectively. The denitrification efficiency (theoretical) and kinetics parameters for COD decay were calculated. The highest performance was verified in the Step III (R = 2) and HRT of 11 h with NH and TN removals of 84% and 65%, respectively. The TN removal efficiency (65%) was considered satisfactory, since the theoretical denitrification efficiency expected for this condition (R = 2) is 67%, without addition of an external carbon source. The lowest nitrification efficiency values were obtained in HRT of 8 h in the Step I and II (R = 0.5 and 1, respectively), indicating that the nitrification time (3 h - aerobic phase) may be the limiting factor in this HRT. The COD removal efficiency was high in all assays (>95%). The values of the kinetic degradation constants of organic matter were close for all recirculation rates, and the highest values were recorded for the HRT of 8 h and R = 1 and R = 2 (-0.48 and -0.43, respectively).
本工作旨在评估屠宰废水在厌氧-缺氧-好氧组合反应器中的脱氮效果，评估循环率和水力停留时间的综合影响。通过利用内源性电子供体，将液相从好氧区循环回缺氧区，促进反硝化。应用了三种循环率（R：0.5、1 和 2）和三种水力停留时间（14、11 和 8 h）。根据评估的因素（循环率和 HRT），将反应器的运行分为 3 个步骤（I、II 和 III），以达到使反应器不同隔室能够达到令人满意的运行条件。在实验过程中，反应器以平均总氮（TN）和化学需氧量（COD）65 mg/L 和 580 mg/L 进料。计算了反硝化效率（理论）和 COD 衰减动力学参数。在第三步（R=2 和 HRT 为 11 h）中验证了最高性能，NH 和 TN 的去除率分别为 84%和 65%。TN 去除效率（65%）被认为是令人满意的，因为在这种条件下（R=2）理论反硝化效率预期为 67%，无需添加外部碳源。在第一步和第二步（R=0.5 和 1，分别）中，HRT 为 8 h 时硝化效率最低，表明硝化时间（3 h-好氧阶段）可能是该 HRT 的限制因素。所有试验中的 COD 去除效率均较高（>95%）。所有循环率下有机物的动力学降解常数值都接近，在 HRT 为 8 h 和 R=1 和 R=2 时记录到最高值（分别为-0.48 和-0.43）。
