Fábio Orssatto

Optimization of the pretreatment of wastewater from a slaughterhouse and packing plant through electrocoagulation in a batch reactor

ABSTRACT The purpose of this study is to evaluate the removal of chemical oxygen demand (COD), turbidity and color of wastewater from a pig slaughterhouse and packing plant through the electrochemical technique and to optimize the ΔV (electric potential difference) and HRT (hydraulic retention time) variables in an electrocoagulation batch reactor using aluminum electrodes. The experimental design used was rotatable central composite design. For turbidity, the values for removal efficiency obtained varied from 92.85% to 99.28%; for color, they varied from 81.34% to 98.93% and for COD, they varied from 58.61% to 81.01%. The best optimized conditions of treatment were at 25 min for the HRT and 25 V for the ΔV, which correspond to electrical current of 1.08 A and a current density of 21.6 mA cm−2. The aluminum residue varied from 15.254 to 54.291 mg L−1 and the cost of the treatment was US

Shewhart's control charts and process capability ratio applied to a sewage treatment station

4.288 m−3. The novelty of the work was the simultaneous optimization of three response variables using the desirability function applied to the treatment of wastewater from slaughterhouses.

Optimization of the nitrification process of wastewater resulting from cassava starch production

The current study used statistical methods of quality control to evaluate the performance of a sewage treatment station. The concerned station is located in Cascavel city, Parana State. The evaluated parameters were hydrogenionic potential, settleable solids, total suspended solids, chemical oxygen demand and biochemical oxygen demand in five days. Statistical analysis was performed through Shewhart control charts and process capability ratio. According to Shewhart charts, only the BOD(5.20) variable was under statistical control. Through capability ratios, we observed that except for pH the sewage treatment station is not capable to produce effluents under characteristics that fulfill specifications or standard launching required by environmental legislation.

Velocity Simulation of an Electrochemical Reactor for Textile Wastewater Treatment

ABSTRACT The present study has the objective of optimizing operational conditions of an aerated reactor applied to the removal of ammoniacal nitrogen from wastewater resulting from the production of cassava starch. An aerated reactor with a usable volume of 4 L and aeration control by rotameter was used. The airflow and cycle time parameters were controlled and their effects on the removal of ammoniacal nitrogen and the conversion to nitrate were evaluated. The highest ammoniacal nitrogen removal, of 96.62%, occurred under conditions of 24 h and 0.15 L min−1 Lreactor−1. The highest nitrate conversion, of 24.81%, occurred under conditions of 40.92 h and 0.15 L min−1 Lreactor−1. The remaining value of ammoniacal nitrogen was converted primarily into nitrite, energy, hydrogen and water. The optimal operational values of the aerated reactor are 29.25 h and 0.22 L min−1 Lreactor−1. The mathematical models representative of the process satisfactorily describe ammoniacal nitrogen removal efficiency and nitrate conversion, presenting errors of 2.87% and 3.70%, respectively. GRAPHICAL ABSTRACT

Gráfico de controle da média móvel exponencialmente ponderada: aplicação na operação e monitoramento de uma estação de tratamento de esgoto

A limitation for the use of electrocoagulation for wastewater treatment is its complexity, since the process is affected by many variables, including the hydrodynamics in the reactor. This paper aimed to present a simulation, through Computational Fluid Dynamics (CFD), of the flow and velocity field of a bench scale electrocoagulation reactor for textile wastewater treatment, with the goal of selecting the best design for the cell, which consists in a continuous, multiple parallel plate reactor. Six scenarios were proposed combining the different values for the two studied variables: electrode width (7 cm, 9 cm and 11 cm) and number of electrodes (5 pairs or 6 pairs). The CFD simulations were carried out within the software COMSOL Multyphysics, which solved the Navier-Stokes equations for the incompressible, laminar, steady-state conditions. The results showed that from the scenarios, the best for the desirable conditions within the reactor (good mixture, low velocity profile and few stagnant zones) were the configurations with 5 pairs of 7 cm wide and 6 pairs of 9 cm wide electrodes. A definitive design for the reactor will possibly be achieved in future studies which will include simulations for the concentration profile.

RECICLAGEM DOS BANHOS RESIDUAIS DE CURTIMENTO AO CROMO, ATRAVÉS DA RECUPERAÇÃO DO MESMO POR SEDIMENTAÇÃO

This work was intended to assess the performance of a sewage treatment plant through letters of statistical quality control of exponentially weighted moving average. The sewage treatment plant is located in the municipality studied of Cascavel, Parana, the parameters measured were the hydrogenionic potential (pH), settleable solids (SetS), total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD). The EWMA letters accused that sewage treatment station has good statistical performance for the pH, total suspended solids, COD and BOD and failures for settleable solids. The EWMA control letters are presented as a good alternative in monitoring of sewage treatment plants.