All food and beverage production and packaging facilities generate wastewater during their production process. The wastewater produced has varying characteristics of organic content, pH, temperature, or toxicity. At times, the characteristics change nearly instantly, and may be caused by product changeover, batch discharge of brines, sanitation processes, power outages, or human error. The rapid change of wastewater character from these events can be troublesome and cause wastewater treatment system inhibition or upset conditions.
When high strength waste (HSW) inhibits wastewater treatment processes, it may put the facility at risk of violating discharge permit limits. Violations of these permit limits can result in a notice of noncompliance, notice of violation, fines, and administrative orders for system modifications. Persistent or willful violations can result in criminal charges being levied against facility owners and operators.
What is high strength wastewater?
Foods and beverages are processed in many ways and the characteristics associated with the production of them generally vary based on the facility. In general, high levels of BOD, TSS, phosphorus, nitrogen, chemicals, or FOGs (fats, oils, and greases) can cause performance issues within treatment plants and may lead to upset conditions if they are not handled appropriately.
Dairy Processing Facilities
Based on production needs and scheduling, wastewater characteristics may vary frequently, causing significant difficulties in effectively treating the wastewater. Variable loads, high-strength waste, significant variations in pH levels, are frequent issues that may pose a performance threat for dairy processing facilities.
In these facilities, variations are often due to clean-in-place (CIP) procedures and product spills.
Clean-in-Place systems are utilized to clean tanks, equipment, and piping. However, the chemicals used for these procedures can alter pH levels in the wastewater from the production facility.
Product Spills are similar to death and taxes; guaranteed to happen from time to time! These spills likely have high concentrations of BOD, nitrogen, phosphorus, and chlorides.
Food Processing Facilities
Meats and poultry, canned goods, snacks, candies, and other food processing facilities also generate wastewater with varying characteristics. Processes for different lines of foods as well as different production lines may cause significant changes to wastewater from these facilities. Frequently, wastewater from food processors may be high in BOD, total suspended solids (TSS), nitrogen, phosphorus, chlorides, and have varying pH levels.
Breweries
Similar to dairy processing facilities, breweries also utilize CIP systems throughout production facilities to ensure cleanliness and sanitation of equipment, vessels, pipes, etc. In addition, carbohydrates and proteins used in the brewing process also can cause varying wastewater characteristics. Wastewater from these facilities may experience high levels of BOD, TSS, nitrogen, and phosphorus.
Why is HSW an issue for a treatment facility?
Treatment plants are generally designed for average peak flow rates and average wastewater characteristics to ensure the most efficient and effective treatment is provided for the majority of wastewater. While biological treatment systems may have the ability to treat high strength waste, it is rarely efficient in doing so and may cause a system upset.
For example… think about the wastewater treatment process as though it were your body.
Once a week, you go out for a couple beers with friends after work. Everything is wonderful. Your body handles and processes this without any issues.
But last week Thursday, it was your birthday. So you have cocktails with friends and enjoy your day. While your body is still able to handle the input, you feel nauseous, wake up with a headache and some wicked heartburn.
The hangover you experienced after cocktails is similar to the effect of high strength waste for a wastewater treatment plant. While some facilities are able to treat wastewater with higher concentrations of nutrients and chemicals, they are still biological systems with living organisms providing the treatment – meaning that they experience the hangover from the high strength wastewater.
And, in the same way that really overindulging will likely make you sick; treatment systems can only handle so much before system upsets occur.
Managing your high strength waste discharges
Production Process Practices
While every facility is unique, there are some common production practices that processors may employ to minimize the impacts on downstream operations. Staging or staggered start times for CIP processes can reduce hydraulic loading and rapid pH changes associated with sanitation and cleaning processes. Alternative chemistry and adherence to usage policies can help ensure that only amounts of chemical necessary to meet sanitation needs are used.
In-Plant Segregation
Segregating high strength flows from normal strength directly in the production facility provides the ideal solution for providing appropriate treatment for the wastewater. However this is typically only an option during the original design phases of the production facility or during significant upgrades that include processing additions.
Active Diversion
Diversion allows for the capture of spills or other concentrated discharges. Using lift stations or flow transfer equipment, or installing new multi-stage diversion equipment are options that make active diversion an option for nearly every facility. The level of sophistication can be developed based on the level of risk avoidance desired by each facility.
Diverting HSW can provide numerous benefits for the wastewater treatment facility, including:
- Protecting your treatment system from slug loads (including chemical and biological processes)
- Actively managing your influent loading – this allows you to balance loading across daily discharge, allows you to remove the highest load factors for off-site treatment (such as land application), provides the ability to bypass the lowest strength to minimum required treatment, and allows for split loading to maximize the benefit of an anaerobic/aerobic treatment system.
- Managing your cost for wastewater treatment
- Compliance with regulatory requirements
What are we diverting?
The simple answer is: Anything that can be better managed outside of the normal process flow of the treatment system.
Some of the most common characteristics for diverted wastewater in the food and beverage industry include wastewaters with:
- High TDS – brine/sugars
- Concentrated sanitizers/cleaning chemicals
- Dramatic pH swings
- Concentrated process wastes
- High levels of solids
- High COD/BOD
- High nutrient levels (such as phosphorus and nitrogen)
- Production spills and
- Contaminated clean water (COW/NCCW)
Parameters for Diverting
With technological advances in wastewater management, there are now numerous sensors and methods for detecting and diverting high strength wastewater. The most common, and most effective means of detecting wastewater containing higher levels of contaminants include:
- pH sensors
Continuously monitoring influent to the treatment process, pH sensors identify wastewater with both high and low pH
- Conductivity sensors
Measure TDS levels in wastewater to divert if needed
- Turbidity sensors
Instream measuring for particle solids and COD
- ORP Sensors
Provide monitoring for oxidizing chemicals
- Total carbon / total organic carbon sensors
Depending on the wastewater treatment plant and processes in place, diverted high strength waste is then hauled offsite, blended into the treatment process at a slower rate to help control loading to the system, or may be treated with an anaerobic process.
Understanding and effectively managing the high strength waste at your facility contributes to the overall success of your wastewater treatment plant. If you’re looking for a more effective solution for managing your wastewater, put our expertise to work for you. Our dedicated engineers and operators provide custom solutions to meet your unique needs – whether that’s process optimization, facility upgrades, or ongoing operations support.
