BioChem Technology is a research and technology firm that specializes in the monitoring, optimization and control of wastewater treatment processes. By combining high level consultation services with a suite of proprietary monitoring and control technologies, BioChem’s experts can help plant owners and operators meet increasingly stringent effluent standards, reduce operating costs and increase the capacity of wastewater flow treated - without major capital expenditures.

Our Mission

BioChem’s mission is to improve the process in activated sludge plants, particularly BNR plants, through optimal control solutions.

The purpose of optimal control is to:

• Improve energy efficiency
• Stabalize the biological processes
• Improve the effluent quality
• Minimize the effluent nitrogen

Capabilities

BioChem does all research and development, applications engineering, modeling and programming in-house. Fabrication and assembly are done in our own workshop or in UL™ certified shops.

Services

• Secondary treatment process design and design review
• Process consulting and troubleshooting
• Process modeling and simulation (using BioWin™ and GPS-X™)

Products

• BACS - Bioprocess Aeration Control System
• BIOS - Bioprocess Intelligent Optimization System
• Custom controllers for secondary treatment, such as carbon dosing, pH control, SRT control

The Bioprocess Aeration Control System (BACS) uses process-based calculations to combine the control of the aeration blowers and the control valves in the reactor tanks to achieve precise levels of dissolved oxygen (DO) in each individual aeration zone . This in turn stabilizes the treatment process, improves treatment efficiency and reduces aeration energy requirements by as much as 40%. The BACS has a number of unique features that conventional feed-back control either cannot provide or cannot do well. These include “most-open-valve” logic, self-tuning for all process and condition changes and reduced valve actuator wear.

Traditional aeration control systems use an approach called PID (proportional-integrative-derivative) control loops to:

• Control the blowers to maintain a constant pressure in the pipe header that supplies the diffused air to the aerobic zones.
• Adjust the airflow to each zone by adjusting the valve position and, hence, the DO level in each aerobic zone.

Experience has shown PID control to be a poor method of controlling residual DO concentrations. PID parameters are typically tuned to control average or typical influent conditions. However, because the contaminants load to a plant changes throughout the day, actual conditions are never really “average” and hence, one of two scenarios typically occurs depending on the current loading. During low loading periods, PID control loop systems will over-tune and cause large oscillations in the DO concentration in the aerobic zones. And during high loading periods when the PID control loop is under-tuned, low DO concentrations will occur as the control system tries to “catch-up” to the increase in oxygen demand. Because the loading of the incoming stream is constantly changing, this means that the treatment system is virtually never operating at an efficient level.

In addition, the blower controls do not communicate with the valve controls, and each valve control is independent of the others, so changes in air flow in any one zone can lead to pressure oscillations and instabilities between control loops.

The BioChem BACS does not use PID control loops, but instead utilizes a proprietary three-step approach to maintaining a dissolved oxygen set-point. First, the BACS uses changes in airflow rate and residual DO in each control zone to calculate changes in respiration rate, and from that it calculates the airflow requirement of each zone. Second, it sends the total airflow requirement (the sum of the individual zones) to the blower control. Finally, when the blowers have reached the new set point, the BACS quickly and efficiently adjusts the control valves to each aerobic zone to provide the airflow calculated by the control system. It then holds everything steady until the system stabilizes, typically 10 to 15 minutes, before it repeats the process.

The Bioprocess Intelligent Optimization System (BIOS) is an integrated hardware and software system that enables real-time monitoring and control of wastewater treatment operations based on the dynamically changing biological activity occurring in the bioreactor. The BIOS, shown graphically below, controls the secondary treatment process to provide optimal conditions for biological (microbial) treatment.

The BIOS uses a customized feed-forward simulation and control algorithm to determine and adjust the real-time dissolved oxygen set-point and internal recycle flow (IRQ) ratio necessary to meet treatment goals while minimizing energy consumption. It manages the supply of air to each zone of the aeration basin to achieve the precise level of nitrification required to meet the plant’s specific permit requirements, and it controls the recycle flow in the tank to maximize the amount of nitrogen removed from the system.

The Bioprocess Aeration Control System (BACS) uses process-based calculations to combine the control of the aeration blowers and the control valves in the reactor tanks to achieve precise levels of dissolved oxygen (DO) in each individual aeration zone (see below). This in turn stabilizes the treatment process, improves treatment efficiency and reduces aeration energy requirements by as much as 40%. The BACS has a number of unique features that conventional feed-back control either cannot provide or cannot do well. These include “most-open-valve” logic, self-tuning for all process and condition changes and reduced valve actuator wear.

Traditional aeration control systems use an approach called PID (proportional-integrative-derivative) control loops to:

• Control the blowers to maintain a constant pressure in the pipe header that supplies the diffused air to the aerobic zones.
• Adjust the airflow to each zone by adjusting the valve position and, hence, the DO level in each aerobic zone.

Key BIOS Advantages:

• The system insures the plant is operated according to the engineer’s design specification.
• Discharge levels are more stable.
• There is improved nitrogen and phosphorus removal, resulting in reduced energy and chemical costs.
• Sludge production from the post-anoxic zone is minimized.
• The overall carbon footprint of the plant is minimized.

It is important to note that the BIOS and the BACS are complementary products and that although they are often applied individually, they can also be applied together. Neither the BIOS nor the BACS are plug-and-play; rather they are highly customized for each individual application. This means that each application requires significant process knowledge, and the products cannot simply be copied and transferred to other applications.