A Practical Path to Wastewater Compliance

A Practical Path to Wastewater Compliance

THE CHALLENGE

When a subsidiary of a global manufacturer of spray‑dried natural ingredients learned that its municipal wastewater discharge permit was about to be updated, leadership knew action was needed—and quickly. The new permit would impose tighter limits on pH, solids, organic loading, and discharge flow, creating both operational and financial risk for a facility already operating within tight physical and budgetary constraints.

The company had a strong track record as a responsible community partner and wanted to stay ahead of potential violations. To explore their options and avoid unexpected fines—or worse, a shutdown of wastewater discharge—they turned to Anguil for help.

Early conversations made one thing clear: pH compliance was non‑negotiable. The city made it clear that a single pH violation would trigger an immediate notice of violation, followed by steep fines and possible suspension of discharge privileges.

Unfortunately, this facility produced wastewater across one of the widest pH ranges Anguil typically encounters. Tomato- and vinegar‑based process streams come in around pH 3, while CIP operations introduced short bursts of wastewater with pH as high as 12–14. Any solution would need to reliably handle both extremes—automatically and without fail.

At the same time, the facility’s discharge flow told a story of its own. For most of the day, flows were below 100 GPM. But during CIP events, wastewater surged to more than 400 GPM in a short window. The updated permit, however, capped discharge to the city sewer at 100 GPM due to upstream capacity limitations.

As Anguil dug deeper, additional constraints surfaced:

• Wastewater contained elevated TSS, ammonia, and BOD
• The city required 100% secondary containment for 30,000 gallons of glacial acetic acid stored onsite
• The site had almost no available real estate for new construction
• Existing sumps commingled industrial wastewater with sanitary flows, which would need to be corrected

It was clear this wasn’t just a treatment challenge—it was a systems challenge.

THE SOLUTION

Anguil worked closely with the client to quantify the real-world impact of the updated permit. Together, they evaluated the cost of violations and surcharges, the capital required for various treatment options, and the likelihood of corporate approval for major investments.

Technically, Anguil could design a system to reduce TSS, BOD, and ammonia using a dissolved air flotation (DAF) system and sludge dewatering. But when the numbers were put on the table, the return simply wasn’t there. Paying municipal surcharges for ammonia and residual BOD made more financial sense than installing and operating a full treatment train.

What did make sense was eliminating the risk of violations altogether and controlling discharge flow—while keeping capital costs in check.

Anguil initially developed a comprehensive treatment concept, including storage, pH adjustment, DAF, and a new treatment building. But geotechnical studies revealed that foundation work alone would drive costs well beyond what corporate leadership was willing to approve.

Rather than forcing a one-size-fits-all solution, Anguil recalibrated.

By listening closely to corporate feedback and site constraints, Anguil helped the client refocus on what mattered most:

• Guaranteed pH compliance
• Flow equalization to meet the 100 GPM discharge limit
• Sufficient storage to manage both process variability and secondary containment requirements
• A design that fit within the existing site and allowed future expansion if needed

The final solution was a fully automated pH adjustment and flow control system, built around:

• A new dedicated process wastewater sump
• Approximately 80,000 gallon storage capacity in FRP  tanks installed outdoors
• Continuous pH adjustment with mixing, and chemical dosing
• PLC-based automation with VFDs, alarms, and remote access
• Bench testing to confirm chemical dosing rates and operating costs

By repurposing space inside the existing production building and avoiding new foundations, the customer dramatically reduced capital costs while still meeting all critical permit requirements.

THE RESULT

Anguil collaborated closely with the customer and their third-party engineer to finalize layouts, instrument placement, and sump integration. Equipment skids were fabricated, leak-tested, and delivered ready for installation. The customer’s maintenance team handled field installation, while Anguil supported commissioning and startup.

Once online, the system performed exactly as intended. Automated controls minimized operator involvement, and remote access allowed Anguil engineers to fine-tune performance during commissioning. Real-time alerts and reporting gave the operations team confidence that compliance was being maintained around the clock.

In the end, the customer achieved exactly what they needed:

• Reliable pH compliance, eliminating the risk of violations and shutdowns
• Controlled discharge rates, fully aligned with municipal constraints
• A significantly lower capital investment than originally anticipated
• Automated, low-touch operation that reduced staffing demands
• A flexible platform that can support future treatment upgrades if regulations or business needs change

By taking a holistic, collaborative approach, Anguil helped the client navigate a complex regulatory challenge without over‑engineering the solution—delivering compliance, confidence, and long-term value.

Odor Elimination: Rendering

Summary

In the Rendering Industry, odor control equipment has been in use since the early 1970’s about the same time Anguil was formed and started serving clients with the best available air pollution control equipment. Typical early applications of air pollution control equipment in rendering consisted of a direct fired afterburner for destruction of the organic emissions (odor, ammonia, fats, grease, and particulate) being emitted from the cooker process. A properly designed afterburner was capable of providing reliable destruction of the organic emissions while operating at temperatures of 1200°F or higher.

As technologies evolved, fire tube boilers that utilized the waste heat of the afterburners were added to produce steam for the steam intensive plant process. The use of the waste heat boilers were the first step in heat recovery of the afterburner. The addition of the waste heat boiler to an afterburner would typically make the overall system efficiency of the two components in the high 70% to low 80% range. However, the overall system efficiency was only this high if the total production of steam from the waste heat boiler was constantly used. Intermittent use of the steam production severely lowered the overall system efficiency and increased the operating cost.

Other applications of different technologies included the use of Thermal Recuperative Oxidizers, which utilize a shell and tube stainless steel heat exchanger. The Thermal Recuperative Oxidizers were not used with waste heat boilers due to their lower outlet exhaust temperatures, but still utilized Economizer units for pre-heat of make-up feed water. Typical heat recovery performance of a shell and tube heat exchanger was around 60 – 70%. The lower efficiency of the shell and tube type heat exchanger vs. a waste heat boiler still averaged to a lower annual operating cost on applications were large boilers were already existing, and steam generated by a waste heat boiler could not be utilized on a continuous basis.

The Challenge

Rising energy costs and the social pressures for improved Environmental Social Governance (ESG) around one of the oldest recycling industries, Rendering, has led to the need for implementation of better environmental controls. With residential areas encroaching on Rendering plants, odor control of storage, loading, grinding, and transport areas has become important. The larger air flows associated with controlling these areas make the use of higher efficiency technologies a must in order to conserve energy and meet today’s carbon reduction goals.

The Solution

Regenerative Thermal Oxidizers (RTOs) are becoming more commonplace to solve these challenges, but the importance of an experienced team to supply this equipment is critical. Anguil has the experience to ensure stringent odors are minimized, proper materials of construction are used, and consideration has been made for particulate and high moisture processes. Pre-treatment is often part of an integrated RTO odor control solution in Rendering due to the difficulty in treating Ammonia (NH3) and Hydrogen Sulfide (H2S), two common components of cooker exhaust. An inlet Venturi Scrubber removes the heavy wetted particulates followed by a Dual-stage Scrubber to remove the NH3 and acid gases to prevent the formation of NOx and SO2 in the RTO.

The Result

With the multi-stage solution, the initial Venturi Scrubber uses a centrifugal action to ready the gas stream before entering the first-stage Scrubber that treats the ammonia. Leaving the top of the initial packed tower into the bottom of the Hydrogen Sulfide second-stage section, the waste gas is further prepared for final treatment of Volatile Organic Compounds (VOCs) and Hazardous Air Pollutants (HAPs). A three-canister RTO provides a means to eliminate a short duration “puff” of untreated odors from the RTO during valve cycling. With such high intensity odors in a Rendering application, it is vital to remove greater than 99% of any entering waste components. Leaving the exhaust stack of the RTO, final regulated emission levels are met while minimizing CO2 production with the highly energy efficient RTO technology.

Project Highlights

• Stainless steel material is used to maximize equipment life when exposed to incoming acidic gas streams
• Specially designed ceramic media heat recovery beds in the RTO to better resist particulate plugging
• Properly sized burner and combustion chambers for maximum performance and flexibility for fluctuating operations
• Proven controlled bake-out program to clean RTO ceramic media to maintain optimal performance

No Half-baked Idea

The Challenge

Ready-to-eat meals, freshly baked goods, and essential groceries draw loyal customers to a chain of convenience stores; they just also happen to sell gasoline. The chain’s nutritious food is locally sourced, processed, and packaged for distribution to almost 1,000 stores in the United States. This company is uniquely positioned as vertically integrated, whereas much of the supply chain is owned by a single corporation serving a common market and customer segment.

One such vertical operation is a commercial bakery that supplies the company stores with fresh bread, bagels, buns, doughnuts, muffins, and snacks. It is a state-of-the-art facility focused not only on quality, but operational energy efficiency and a low carbon footprint. When the company decided to increase capacity, they took a wholistic approach to the design and layout. New bread and bun ovens were purchased along with proofers which are large enclosures kept at elevated temperatures to help dough rise. Most commercial bakery ovens and the corresponding proofers rely heavily on natural gas or electric elements to generate heat for baking the products.

While working with local regulators to satisfy air pollution control requirements for the new lines, company engineers explored the utilization of waste heat from pollution control systems. Oven exhaust contains Volatile Organic Compounds (VOCs) like ethanol, as well as odors that must be treated to comply with national emission standards.

Like many other industries, food processors often find that the best available control technologies for emission and odor abatement are thermal and catalytic oxidizers. Oxidation systems use time, temperature, and turbulence to break down pollutants into Carbon Dioxide (CO2), heat, and water vapor. This bakery was particularly focused on minimizing the CO2 output from the planned oxidizer installation by utilizing the heat from combustion. It would not only save operating costs, but also keep with the company’s commitment to do right by customers and the community.

The Solution

Anguil Environmental Systems was one of the first air pollution control system suppliers in the early 1990s to design and install oxidizers that met regulations limiting bakery oven emissions and odors. Three decades later, Anguil remains a leading supplier of both thermal and catalytic oxidizers to the baking industry. Regenerative Thermal Oxidizers, or RTOs, have been increasingly used on commercial ovens for their energy-efficiency operation. RTOs are typically 95% thermally efficient whereas catalytic oxidizers range from 60-80%. However, catalytic oxidizers are still widely applied at bakeries due to their lightweight construction which makes a rooftop installation more feasible, putting them near the ovens while eliminating costly duct runs.

This bakery was like many others in that regard; a roof installation made catalytic oxidation the most logical equipment selection. Two Anguil Model 50 (5,000 SCFM capacity) catalytic oxidizers would be installed, one for each oven, on dedicated roof platforms. During operation, ethanol-laden oven gases are pushed into a stainless-steel, shell-and-tube heat exchanger inside the oxidizers via a system fan. The contaminated airstream is progressively heated while traveling through the heat exchanger towards the combustion chamber. The cleanable, heat exchanger allows for self-sustaining operation with no auxiliary fuel usage at Lower Explosive Limits (LEL) levels of 8-12%. At the burner, the process gas is raised to the catalyst operating temperature. As the heated gas passes through the catalyst, an exothermic (heat releasing) reaction takes place as the pollutants are destroyed. The hot, purified air then passes through the opposite side of the internal heat exchanger and transfers thermal energy to preheat the incoming air.

This environmentally conscious bakery was interested in further reducing operating costs and energy consumption. Therefore, Anguil recommended and designed a secondary heat recovery system to capture additional waste heat from the two oxidizer stacks. Finned tube heat recovery coils with propylene glycol-heated fluid were installed to recover over 2.5 MMBtu/hr from the oxidizers and provide a heat source for the proofers.

The Result

The Anguil oxidizers achieve over 98% destruction efficiency of the ethanol emissions while reducing the carbon footprint of the bakery’s operations. The systems incorporate a self-cleaning ceramic filter, which prevents grease from plugging or fouling the catalyst. The Anguil design also ensured that the abatement devices would have no back pressure in the ductwork which could impact oven performance or product quality.

Wastewater Compliance Techniques For Food Processors

THE CHALLENGE

Food production is a demanding and competitive process. Executives are continually confronted by product development processes, competitors, and deceptive practices for economic profit.  In today’s environmentally aware climate, reputation is crucial. Producers worry they could be perceived as environmentally and socially irresponsible. If they are, some retail chains may refuse to stock their brands until they make extensive, and often expensive changes.

Many producers are facing a new, and unexpected, complicating factor: failing and undersized Publicly Operated Treatment Works (POTWs). Wastewater previously discharged with little processing may now be subject to surcharges. Publicly Operated Treatment Works struggle to meet increased Environmental Protection Agency (EPA) regulations, while making infrastructure improvements to accommodate the greater load.

Another obstacle: treatment system operators, with decades of experience, are retiring. Unfortunately, the knowledge of how to run their outdated treatment system retires with them. This leaves system owners and executives wondering how to replace that knowledge base while meeting new regulations.

In the face of increased regulatory control, rising environmental concerns about wastewater, and a retiring workforce, food producers are seeking cost-effective ways to stay in compliance.

THE SOLUTION

Anguil Environmental provides highly engineered equipment and service solutions that solve complex industrial air and water concerns. Anguil follows a very simple, but effective, four-step approach that addresses economic, operational, and compliance challenges.

The first step is to evaluate the situation and parameters. We collaborate with the client to understand their challenges and determine the project needs and objectives. We gather benchmark data to assist with alignment of solutions that offer the best return on investment (ROI), then work with the customer to understand their decision process and criteria to ensure we can fulfill all their requirements.

The second step is exploring all treatment and operational processes in the Anguil lab. Anguil confirms all potential treatment and process options that align with the customer objectives.  This step involves wastewater samples in our in-house wet lab to validate potential treatment protocols.

Testing in-house provides on hand data for evaluation of viable treatment options, which is then used to generate a simple Process Flow Diagram (PFD) to illustrate the equipment needed to meet customer parameters.

The third step is placing a pilot system onsite to test waters. With the client satisfied with our lab trials, we ask if they require a pilot system to validate the treatment approach in normal conditions onsite.

THE RESULT

The fourth, and final step in the process is commercial deployment. After completion of lab testing, discussion of various equipment options and testing against the business case, Anguil provides a firm proposal for a treatment system which would meet the treatment efficacy and business needs of the customer. The proposal contains detailed information on the treatment system, estimated operational costs, and options for installation, start-up, and commissioning. The flexible approach allows the customer to choose the package that best suits their needs. Additionally, Anguil’s Aftermarket and Service group is proactively in touch, ready to provide long-term system, and parts support.

Anguil follows a better approach to solving complex water challenges, which starts with listening to the client’s needs and business case. Anguil advocates an efficient process that would provide the client with the information they want to make an informed decision.

Organic Particulate Filtration

The Challenge

A food products company that mixes various types of waxes and other components to make the base for chewing gums was faced with the issue of cleaning up a slightly odorous, visible emission being exhausted from two of their process lines. The components of the emission were hot particles of chewing gum and some volatile organic compounds (VOC’s). The particles would quickly clog a conventional filter system or electrostatic precipitator, neither of which could control the odor off the process line. In addition to the emission problem, the condensation of the exhaust stream was damaging the roof of the facility.

The Solution

After thorough technical evaluation, the Self-Cleaning Ceramic Filter (SCCF) was recommended as the ideal solution for processing the exhaust and Anguil Environmental Systems was selected to solve the visual, odor and VOC problem. 

The Result

In order to demonstrate to the client that this was a viable solution, Anguil utilized their portable self-cleaning ceramic filter test unit before any purchase decisions were made. During the test, the process lines were run through the ceramic filter in two modes, hot and cold.

First, the system was run in the hot mode with a gas burner firing continuously at 400º-500ºF heating up the process air. The once visible plume disappeared as it passed through the ceramic filter and catalyst module. Second, the ceramic filter was used without heat, and again, the visible plume disappeared as it passed through the ceramic filter and catalyst module. Twenty-four hours of production were run across the ceramic filter without heat and the visible emission was acceptable from a customer and environmental regulation standpoint. However, when utilizing a cold process stream, particulate matter accumulated on the ceramic filter which had to be periodically cleaned by firing the burner. When the cleaning cycle began after the two shifts, a dense white plume was emitted for 90 seconds while the filter element was burned clean. The customer, a food products company, felt that this emission level was not acceptable so they decided the continuous hot running ceramic filter would better fit their needs. It should be noted that for certain operations with visible emissions, the pulse cleaning mode may be acceptable. Many local authorities allow companies to discharge up to five minutes per hour without control.

After the customer determined that the ceramic filter would solve their problems, Anguil proceeded to manufacture and install a 1,000 SCFM (1,577 Nm3/Hr) ceramic filter unit. The unit was used to process the exhaust from two process lines. One of the more significant benefits to the company was Anguil’s ability to reduce the air volume from the processes. Initially, the two gum-based mixers each had a 3,000 SCFM (4,731 Nm3/Hr) high volume, low static pressure fan that was exhausting to atmosphere. Tight covers on the mixers minimized the escape of odor into the mixing room. With the close capture hoods it was possible to reduce the air volume from 6,000 SCFM (9,462 Nm3/Hr) exhaust to 1,000 SCFM (1,577 Nm3/Hr) exhaust from the two process lines. The net air volume reduction of 82% reduced both the capital cost and the operating cost of the system.

In order to guarantee continuous production in the event of a burner failure, Anguil installed a bypass equipped with conventional roughing filters. The exhaust fan was equipped with an inlet vane control to vary the air volume if only one process line was being used. The control panel was outfitted with a user-friendly PLC first out detection system. The entire ceramic filter system was mounted in a light-weight enclosure to allow for roof mounting without significant structural modifications to the building. Growth capacity was accommodated in the gas burner and the fan section, allowing for the addition of future operations. Anguil’s system engineering provided their client with a solution to their compliance needs at reduced air volume and reduced cost.

Meat Processing Odor Control

The Challenge

For its first two years of production, a food manufacturer based in South Wales, England, focused its production on potatoes. Neighborhood residents voiced no complaints about odors during this time period. However, as new production lines (including barbequed meats and curried chicken) were added, the complaints began, and it became clear that odor abatement equipment was needed to resolve the issue.

Onsite meetings were held to discuss the issue, concerned citizens and the local environmental health officer attended to discuss the best way to handle the situation. The company employs a large percentage of the local residents, and was concerned about maintaining good community relationships, while at the same time it was in need of a building expansion to introduce a new line of curried chicken products. Planning approval became contingent upon the installation of an odor abatement system to control the new and existing odors.

The two-year old factory had been designed to incorporate emission control equipment, and management was committed to installing the most effective technology available. After a thorough technical evaluation, Anguil Environmental Systems, Inc. was selected and contracted to address the odor emission problem and satisfy the building expansion requirements.

The Solution

Although several odor control technologies were discussed — including masking sprays, wet scrubbing, bio-filtration, carbon absorption and catalytic and thermal oxidation — the Regenerative Thermal Oxidizer (RTO) was the only technology that could guarantee the elimination of 99% of the odorous compounds. 

Since future production may produce different odors, it was necessary that the installed technology have the ability to treat a wide range of odorous compounds to a high level of removal/destruction – guaranteed.  Although, the guarantee of nearly complete elimination of the odors was the primary concern, capital and running costs were also of utmost importance. The RTO was selected due to its low operating costs and the fact that no waste is produced as a byproduct of its functioning.

The Result

Following the installation of the RTO, the results were dramatic, and as promised nearly all of the odors have been eliminated. Due to its well-designed odor control strategy, Anguil resolved the odor emission problem, thereby resolving potential community relations/environmental issues, and meeting its requirements for obtaining planning approval for future expansions.

Reducing Dependence on Natural Gas in the Bean Roasting Industry

THE CHALLENGE

Emissions and odors from the bean roasting process have traditionally been treated with an afterburner. This process simply burns the roaster exhaust with natural gas or other fuel types. While this is an effective means of air pollution control, it is not energy or cost efficient.

Recognizing the challenges, Anguil set out to build a more energy-efficient, cost-effective means of handling emissions in the bean roasting industry. Ultimately, Anguil established a system that not only accounts for the unique needs of the application but also achieves environmental compliance at a fraction of the operating cost.

After purchasing a new roaster, a nationally known chocolate roaster company knew their exhaust process needed an upgrade for the increased facility output. Rising fuel costs and sustainability concerns prompted this company to find a more energy-efficient, cost-effective means of emission destruction. Anguil recommended an 8,000 SCFM (12,840 Nm³/hr) RTO to handle the new roaster, nip grinder, and alkalizer at this facility.

THE SOLUTION

With a two-bed regenerative thermal oxidizer (RTO), contaminated process gas is preheated as it passes through beds of ceramic media located in the energy recovery chambers. The process gas moves from the pre-heated chamber toward the combustion chamber, where the volatile organic compounds (VOC) are oxidized, releasing energy into the second energy recovery chamber before discharging to the atmosphere. A diverter valve switches the process gas direction so both energy recovery beds are fully utilized, providing 95% thermal efficiency thereby reducing auxiliary fuel requirements. Under normal operating conditions the unit is self-sustaining, requiring no additional fuel to achieve destruction.

For every 2,500 SCFM (4,012 Nm³/hr) of process airflow increase, the afterburner requires 18 times more natural gas than the RTO. For this application the RTO technology uses, on average, 12 times less natural gas compared to a traditional afterburner.  At $5/MMbtu for natural gas, that could result in over $500,000 in savings for a 24/7 operation utilizing a four-bag roasting machine. This energy-efficient design offers significantly lower operating costs in comparison to other treatment methods commonly used in bean roasting facilities.

THE RESULT

Water vapor was a concern during the design phase of this project, so accommodations were taken to handle the high moisture airstream from the roaster. Water is also added for flavor and sterilization purposes. If precautions are not taken, it could cause system components to seize during freezing weather, accelerate corrosion of carbon steel parts resulting in oxidizer shutdowns during high production times. Anguil engineers recommended a knockout drum with removal pump just upstream of the RTO. Modifications were also made to the fresh air damper to introduce less water vapor and portions of the ductwork were insulated to prevent freezing.

Special consideration was given to the RTO ceramic media to account for any particulate in the airstream, ensuring proper operation. The oxidizer also has a bake-out feature which works much like the self-cleaning feature on an oven. Organic particulates are regularly burned out during a high temperature cycle, which ensures the media does not plug, reduces pressure drops, and lowers electrical consumption.

In addition to the emission and odor control equipment, Anguil provided a 7,000 SCFM (11,235 Nm³/hr) plate heat exchanger and corresponding duct work. This sends approximately 1.5 MMbtu/hr of waste heat from the RTO exhaust stack to a make-up air unit on the roof. This adaptation saved the company over $80,000 a year in heating costs during winter months. On similar applications, Anguil has returned waste heat back to the roasters, which further reduces natural gas consumption and operating costs.

The company was so pleased with the solution Anguil provided; they have purchased two similar systems for their other facilities. The updated systems have resulted in environmental compliance, and lower operating costs for the bean roasting company at all three plants.