By Peter Chawaga, Associate Editor, Water Online
It’s no secret that automation leads to efficiency. When computers do things on their own they are done faster, generally without waste or error, leading to increased production at a lower cost.
This tenant holds true in every field, and when it comes to wastewater treatment, it may finally be catching on. In an article published by Chemical Engineering, J.P. Pasterczyk, a salesperson with GE Water & Process Technologies, called it a “paradigm shift.”
“One recent example of this is a refinery customer in Minnesota,” Pasterczyk said. “Although they were already monitoring their wastewater, it wasn’t enough to control and optimize their processes. Automation would help this customer save money by reducing energy consumption and making for more efficient use of chemicals. In addition to these savings, automation will help them to preserve the health of their activated sludge system while ensuring they never exceed environmental discharge limits.”
Energy is the largest expense at any wastewater treatment plant or industrial operation and it is the primary area where automation can ease cost burdens. For instance, the blowers used in aeration basins can account for 60 percent of a plant’s energy costs, according to Rockwell Automation, and automating this process based on data collected about the effluent can deliver a precise amount of air at a precise basin level for the most efficient removal of solids. This is probably the single most popular and effective use of automation, but there are others.
“In addition, chemical feed in coagulation, flocculation, and sludge dewatering can be automated” to reduce energy costs, Pasterczyk said, adding carbon loading and nutrient addition to the list as well.
Beyond energy savings, automation can make chemical usage and solids handling more efficient and help operations avoid fines for exceeding discharge permits. While his article highlighted industries like food and beverage and chemical processing as being particularly ripe for gains through automation, Pasterczyk believes the benefits are widely applicable.
“There is no single industry with wastewater treatment that would not benefit in some way from automation,” he said. “No matter what the sources of the wastewater, no matter how big the flows are, all industries use a common sequence of steps and the same basic principles of removing fats, oils, and grease, organics, and solids. Each industry has the potential to automate and optimize their treatment processes.”
Despite this universal potential, some obstacles still keep many wastewater treatment operations from fully embracing automation. Pasterczyk said that he believes many operators are not monitoring the process parameters that would demonstrate an opportunity for more efficiency through automation.
“Some paramaters are measured periodically via manual grab sampling, while other online measurements are not quantitative and able to provide process knowledge and understanding,” he said. “Monitoring by manual grab sampling is a great place to explore automation. Converting grab sampling to continuous monitoring provides data to help determine where there are opportunities for improvement in your treatment modules. Get online monitoring equipment in place to obtain process knowledge that leads to better control.”
Other operations that have yet to embrace automation may be held back by budgetary concerns. Pasterczyk recommends laying out a plan for automation in a series of incremental steps, starting with the current state of the operation and projecting a desired level of cost savings in the future.
“One common pitfall is trying to do too much too quickly,” Pasterczyk said of operations that are working to implement automation. “It does not have to be an all or nothing approach. As with any process change, bringing in automation in a non-methodical way can result in chaos. Instead, start with a clear, realistic plan and bring in experts who can help, whether in-house experts or by talking to colleagues in similar industries who have already implemented automation.”
Image credit: "Ashbridges Bay wastewater treatment plant, Toronto" Timothy Neesam © 2009, used under an Attribution 2.0 Generic license:https://creativecommons.org/licenses/by/2.0/