Wastewater treatment plants are facing pressure from both sides regarding chemical use and tightening discharge limits. When we look at chemical reduction as a goal in this industry, it’s mainly about finding alternatives, monitoring chemical usage, and precision dosing. Cutting corners on treatment quality is not an option, which makes it crucial to strike a balance between compliance issues and costly mistakes. Although the environmental factor is important, it’s not the main reason facilities should reduce chemical use. Regulatory and compliance rules are popping up, and facilities are scrambling to find new ways to avoid using chemicals like chlorine, coagulants, and polymers. Let’s dive into some of the modern ways that you can reduce chemical usage in your wastewater treatment facilities.
What Causes Chemical Overuse in Wastewater Treatment?
The main reason to find alternatives to these chemicals is the potential for overuse in wastewater, which can cause machinery issues and health concerns. One of the main reasons chemical overuse occurs is that facilities use a chemical dose for peak or worst-case scenarios, but continue to run that same dosing rate on a regular cadence.
On the other hand, this may also happen due to choking loads of flow or pollutants from storm surges, which can disrupt the current treatment of wastewater. These surges often can lead to operators having to over-dose on chemicals to get it back to normal. These two reasons are the main causes of chemical overuse in wastewater treatment plants, but other factors can lead to it as well.
How To Reduce Chemical Usage in Wastewater Treatment
There are many ways you can reduce chemical use in wastewater treatment, and these methods can help alleviate regulatory pressure on operators to maintain compliance and avoid potential issues. These methods should be chosen based on your plant’s specific needs and the water flow it maintains daily. These methods can be used on their own or in conjunction with others to create an efficient system that uses the fewest chemicals.
Precise Dosing and Real-Time Monitoring
Precise dosing refers to shifting from a fixed dosing rate to a more flexible one, with advanced systems integrating real-time feedback for adjustment. This keeps the dosing at optimal limits throughout the cycle, avoiding overdosing. Typically, this is done using sensors that measure pH, turbidity, ORP, and other parameters to determine the optimal dosing. Additionally, equalization tanks can prevent shock loads from adversely affecting the treatment process, which can reduce chemical costs and usage associated with storm surges. Real-time monitoring is the main reason this would be possible, as it could monitor the water consistently and make adjustments as needed.
Non-Chemical Alternatives
There are alternatives to the chemicals we currently use in wastewater treatment facilities. For example, US disinfection is one of the main alternatives, in which a special light is used to kill bacteria and germs in the water. The light can damage bacterial and viral DNA in the water and reduce disinfection byproducts by reducing the use of chemicals. UV systems often operate continuously and can handle changes in water flow without fail. Ozone or advanced oxidation can be a great option for harder-to-treat contaminants that may also be present in the wastewater.
Biological and Membrane-Based Alternatives
Adding in additional components or opting for components that can handle wastewater treatment without chemicals is another option. For example, moving-bed biofilm reactors maintain higher biomass concentrations, which can sustain treatment performance while using much less space and reducing reliance on chemical oxidants. Bioaugmentation is another option that uses pollutant-degrading microbes instead of chemical treatment. This is usually done initially, killing as many bacteria as possible, then going in with chemical treatment. Doing it this way can eliminate the need for chemical treatment by 25%.
The last option here would be membrane bioreactors, which combine biological treatment and membrane filtration to reduce the reliance on chemical filtration. All of these methods can be used to eliminate full reliance on chemicals, but implementing them in your plant would depend on your particular needs and the type of wastewater.
Process and Operational Changes That Can Help
Sometimes, just optimizing your processes can cut down on your excess chemical usage and give you a more efficient treatment without the reliance on chemicals. Optimizing your pH control is a simple task that can help reduce the coagulant usage. Jar testing to recalibrate dosing can also be essential, especially in changing seasons; dosing may also change. Sludge conditioning and dewatering optimization are also methods that can support maximum efficiency and dosing optimization. Overall, chemical reduction is somewhat easy, as there are multiple ways to achieve it, making it a “low-hanging fruit” for plants aiming to reduce chemical reliance.
Reducing Chemical Usage in Wastewater Treatment Facilities
Reducing chemical use in wastewater treatment can be done in a variety of ways. From alternative options to real-time monitoring and optimization of operations and processes, some options can be feasible for a plant of any size. Realistically, if you’re on a mission to become less reliant on chemicals in wastewater treatment, there are many different options to choose from, making it a somewhat easy switch. Understanding the different options you have for achieving this can help you decide which is best for your plant’s needs, size, and water flow.
