Wastewater Compliance Techniques for Food Processors
By: Kevin Summ, Contributor
In the face of rising surcharges from Publicly Operated Treatment Works (POTWs), an aging workforce and changes in demand from the global COVID-19 pandemic, food manufacturers are looking for cost-effective strategies to stay in compliance while keeping operating costs low.
Food production has always been a demanding and competitive process, and the global COVID-19 pandemic only exacerbated these pressures. Executives are constantly challenged by demand fluctuation, slow product development cycles, competition from healthier alternatives and even food fraud. Like many other industries, food producers must also be cognizant of their environmental footprint and social persona. In fact, some retail chains refuse to stock brands from producers with damaged reputations until they make intensive and expensive changes.
When it comes to wastewater processing, food producers are being hit hard by failing and overcapacity POTWs. Wastewater previously discharged with little care may now be subject to volume and contaminant surcharges, as POTWs repair infrastructure and struggle to meet increased EPA discharge regulations.
Even companies with existing environmental technologies and procedures in place are faced with an aging workforce and subsequent retirements. That means decades of experience and tribal knowledge on treatment systems retires with them. This leaves owners and executives wondering how to replace that knowledge base and ensure they remain in compliance.
Traditional wastewater treatment solutions have not adequately addressed these regulatory, environmental and operational challenges food producers face in a comprehensive and cost-
There are companies in the environmental technology space taking a new, holistic approach to clients with these unique set of challenges. One such company, Anguil Environmental Systems, provides highly engineered environmental equipment and service solutions that solve complex industrial air and water challenges. When aiding companies with water projects, it’s important to follow a simple but effective process—one that can help producers address economical, operational and compliance challenges.
Evaluate Infrastructure & Systems
- Does the facility need new equipment, or will a systems upgrade suffice?
- What are the changing POTW discharge requirements that will affect them most?
- Are producers thinking about increasing production or adding new product lines, and how will this affect their wastewater chemistry and volumes?
- Are they making any changes to their Clean-In-Place (CIP) operations that could impact volumes and water chemistry?
- Does re-using water make any sense?
Nail Down the Requirements
The first (and often overlooked) step is to understand the business case. It is imperative to know what compliance is currently costing. This will give a clearer view of objectives and help determine return on investment (ROI). For example, are you willing to spend more on controls and automation to minimize operator involvement or to better deploy staff in other areas of the facility? What are the costs of doing nothing?
One customer was looking at a total suspended solids (TSS) surcharge cost increase of $40,000 per quarter and a surcharge of $20,000 per quarter for acidic discharge waters. The client was essentially looking at $240,000 in increased operating costs per year. For some food processors, this may be manageable, but for others it is not. Knowing the company’s threshold for these costs is critical.
The second step is to explore and validate process contaminants in a controlled environment. Suppliers with an in-house testing lab can validate all potential treatment systems to ensure they are compatible with the customer processes. One recent company wanted to determine if a solution for TSS removal would get them below discharge requirements. Wastewater samples were evaluated in a wet lab to validate potential treatment protocols. They quickly determined pH/polymer protocol resulted in TSS removals well below the discharge requirements. After bench-testing confirmed the treatment option was viable, Anguil generated a simple Process Flow Diagram (PFD) to illustrate the primary equipment integrated into the treatment train. This train included the appropriate equalization and buffer tanks, pump logistics, clarifier and a filter press for solids handling.
Whenever possible, the third step should always be an onsite pilot system to test waters in situ. Pilot testing is the best way to validate the treatment approach. The operator gets a chance to see how the full-scale system will perform and what maintenance may be required. Often, a pilot system can identify customer specific enhancements to the system design that can improve usability.
Design for Low Maintenance
Most water treatment systems require several technologies inline to meet their effluent treatment goals. Remediation of a light non-aqueous phase liquid (LNAPL) plume, for example, may require an oil/water separator, air stripper and carbon adsorption system to meet discharge requirements. However, it is often wise to add other components to protect the primary treatment equipment—but not necessarily directed at the primary contaminants of concern. For example, installing a cone bottom inlet equalization/feed tank, rather than using a flat bottom tank, allows settleable solids to be captured in the cone prior to further treatment. The cone bottom can be easily accessed to pump out the sludge without draining the entire tank.
Materials of construction are another important consideration related to maintenance and food processing. Care should be taken to choose not only those materials compatible with water contaminants, but also where maintenance activities are likely to occur. For example, the coating or painting of equipment surfaces is not recommended. As these housings are accessed during maintenance, painted surfaces will chip and crack. Though stainless-steel construction may represent larger initial capital cost, the equipment will require less lifetime service.
General equipment layouts should also incorporate regular maintenance activities. Pipe runs should not be located across access hatches and adequate clearance must be given to fully access the trays in low profile air strippers. Large basket strainers must be located high enough from the ground that the baskets can be removed. Instruments that need to be regularly calibrated (such as pH sensors) should not be in elevated duct or pipe runs. Adequate space around commonly maintained areas (pumps, blowers, actuators, belts) should be allowed, if possible, to ensure operators have their boots on the ground and are not working in tight conditions. Deposits, both organic and inorganic, can cause either premature equipment replacement or major maintenance costs to restore full functionality.
Inorganic deposits are well-known. Hardness scale and iron deposition are the two most common culprits. However, there are other equally problematic but more industry-specific ones, such as struvite precipitation in landfill leachate systems. Biofouling from bacterial growth can also quickly gum up a system, but this is often not accounted for in the initial design process. This is either an oversight or because the influent waters are not characterized properly beforehand. Fouling can also occur from the process stream itself, especially when the water contains fat, oil or grease in significant quantities. Inorganic deposit control can be handled in several ways.
Organic deposit control is often overlooked since the potential for biofouling is not commonly characterized during the design phase, especially for pump and treat systems. However, bacterial growth can clog bag filters, foul carbon systems, encumber pipes and blind off membranes. To control biogrowth, operators can either disinfect or discourage bacterial growth by removing environmental conditions which would promote growth (e.g., removing food sources, or adjusting redox potential). Disinfection can be accomplished by the addition of chlorine, sodium hypochlorite, chlorine dioxide, biocides and UV radiation, to name a few. However, each of these systems brings unique operator challenges, especially in terms of chemical handling, health and safety, and disinfection byproducts.
Disinfection should occur as soon as possible in the system to provide maximum protection. It can also be used to shock a system back into compliance when biogrowth is out of control. Long-term management, as well as removal of bioscum, can also be accomplished by injecting biodispersants, which can remove food sources, weaken cell walls and inhibit bacterial reproduction. Most biodispersants are typically safer to handle than biocides or corrosive chemicals and do not react with the treatment system itself.
Lastly, operators should have a preventative maintenance plan in place on the first day of operation and should be aware of all the manufacturers’ maintenance recommendations and warranty exclusions. This includes a complete schedule of mechanical, electrical and controls checks. Performing regular and routine maintenance keeps small problems from becoming maintenance nightmares—and inflating operation and maintenance budgets beyond acceptable levels.
The operations and maintenance costs for large wastewater treatment systems often eclipse the initial capital expenditures. Poor attention to design details can turn a routine maintenance schedule into an oppressive task. Many such maintenance headaches can be avoided if experienced plant personnel are consulted when the system is still on paper.
About the Author
Kevin Summ, Director of Marketing for Anguil Environmental Systems, has 25 years’ experience with the marketing and sales application of environmental systems into various industrial markets. Anguil Environmental provides highly engineered, environmental equipment and service solutions that help clients solve complex industrial air and water challenges across the globe. firstname.lastname@example.org/www.anguil.com/800-488-0230
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