08 May Wastewater Characterization – Knowing What You’ve Got!
I never cease to be amazed at the reluctance of brewers to spend a couple of thousand dollars to find out what is in their wastewater before spending tens or hundreds of thousand dollars on the treatment to comply with regulations. Penny wise pound foolish?
When facing the challenge of complying with municipal wastewater discharge regulations, there is nothing more important than accurate characterization of the wastewater under scrutiny. Without knowing the wastewater constituents and volume it is nearly impossible to predict compliance and treatment required to achieve it. Imagine brewing the next batch of a successful Session without a recipe? Kind of the same issues.
So, what does characterization mean? In short, it means that you have an accurate representation of the pollutants contained in the wastewater (BOD, Suspended Solids, pH, O&G and others), the average flow leaving the facility and the wastewater volumes throughout the day. Omitting any of these three pieces from the characterization risks faulty characterization and a potentially flawed plan moving forward. Although one would think that wastewater is similar for most brewing facilities, in fact it varies dramatically from site to site.
“Before planning a wastewater treatment system, you need to know the wastewater characteristics, wastewater flow and the flow variability to succeed”
First, before designing a plan for characterization, it is important to understand the “driver” for the treatment of wastewater; usually regulatory but often financial as well. A clear understanding of the applicable regulations is critical to success in wastewater characterization and subsequent treatment system design. If regulations are driving the assessment, which parameters are regulated and at what levels? With this understanding, samples can be collected of the wastewater for analysis.
Sample collection involves the collection of wastewater samples from the point in the discharge where all process wastes come together. Sounds simple right? Not really. Access to the right sample point is often obscure and difficult or impossible to access. Should you take a grab sample, 12 hour composite sample, 24- hour composite sample or time proportional? Well, it depends… Some analysis requires grab samples while some requires composites.
Analysis of the samples is just as critical as the collection – weak link in the chain prospective… Knowing what to sample for (regulatory basis), type of sample to collect and the right laboratory to analyze the samples are all critical components to the sampling program. Once again, an error here can cause dramatic issues later. it is also critical to take a number of samples during a variety of production operations and products – understanding variability in wastewater is also important in designing system for its treatment.
Flow Monitoring is a necessary component in the design as well. Knowing the constituents in the wastewater aids in the selection of the technology selected to treat, knowing the flow determines the size of the treatment system components. Keep in mind that, although the total volume generated daily is important, the rate of generation and flow variation is also important. In many cases, the majority of water use and discharges occur during a very short period in the day. Collection and pumping systems need to be sized accordingly.
In summary, wastewater flows and components vary dramatically from facility to facility. Regulations governing the discharge of wastewater vary dramatically from municipality to municipality. Mistakes or oversights in accurately characterizing the wastewater will have dramatic impacts on the cost and effectiveness of the treatment system installed to meet limits of reduce surcharges. Although general characterization form similar facilities is a good place to start, do not rely on “typical” characteristics to assess your facility’s discharge – it probably won’t fit the profile.
One of the best aids to understanding the impact of operations on wastewater and how to characterize it can be found in the Brewer’s Association “Water and Wastewater: Treatment/Volume Reduction Manual.”
Also, check out the following:
EPA’s Wastewater Sampling:
To get a better understanding of the process, also contact your local Industrial Pretreatment Coordinator for the municipality that accepts your discharge. Also, there are always a number of consultants like TSD that can offer suggestions and assist you in designing a program. Give us a call for help.