Modeling and Control of pH in Pulp and Paper Wastewater Treatment Process

Abstract

Pulp and paper industry is responsible for large discharge of highly polluted effluents, which often be treated by biological treatment process. For biological treatment system, pH is an important environmental factor that can influence the activity of microorganisms. In general, the optimal pH for aerobic processes is around neutral pH (7_7.8) and for the anaerobic process is between 6.8_7.2. The control of pH is a difficult link in the biological treatment system due to its nonlinearity and large time-delay. Aiming at the difficult point in the pH control of the biological wastewater treatment system, a mathematical model of pH control is estab-lished in the essay. On this basis, a traditional PID control and a cascade control are adopted to carry out simulation and comparison with MATLAB. The results show that the cascade control has better comprehen-sive effect in terms of response speed, stability and disturbance resistance

Maximum CO2 Utilization by Nutritious Microalgae

“…In our experience, no more than 10 mL of 1 N NaOH, per batch, was needed to hold the pH constant against high CO 2 concentrations. At a larger scale, several investigators have successfully achieved pH control using proportional control, or proportional-integral (PI) control with or without feedback or cascade controllers. , …”

“…At a larger scale, several investigators have successfully achieved pH control using proportional control, or proportional-integral (PI) control with or without feedback or cascade controllers. 47,48 Microalgae as cattle feed is cost prohibitive relative to soybean meal because it requires separation from a dilute solution and is susceptible to contamination. 49 However, optimized microalgal biomass productivity on waste substrates provides an opportunity to meet animal feed demands and reduce global energy, freshwater, and land use.…”

Chemical activation of Microcystis aeruginosa biomass: a promising approach for enhanced diclofenac sorption and water treatment

“…According to Nasr and Moustafa, 61 the average pH value found in urban wastewater ranges from 6.8 to 7.2, with an average of 7.0 in El‐Agamy wastewater treatment plants in Egypt. The pulp and paper industry's ideal pH for aerobic processes is around neutral pH (7–7.8), but for anaerobic processes, it is between 6.8 and 7.2 62 …”

Design and construction of a prototype for acidity level control in coal mining liquid effluents

“…It is known that the prototype corresponds to a system of first order with dead time. From this view point, to obtain the transfer function, the required data was acquired from the response curve ( Figure 5) and, for their validation, were compared with the results obtained by Kang et al (2009) and Rivero Ochoa and Chávez Cuadros (2010).…”