Clean Technologies in U.S. Industries: Focus on Food Processing

Executive Summary
Acronyms
Industry Background
Environmental Issues and Regulations
Clean Technology Developments
Future Trends
References

TABLES

Table 1: Key Organizations in the Food Processing Industry
Table 2: Typical Rates for Water Use for Various Industries
Table 3: Clean Technology and Pollution Prevention Services

1. EXECUTIVE SUMMARY

This report gives a brief overview of the state of the U.S. food-processing industry, with an emphasis on its efforts to incorporate pollution prevention and clean technologies into its processing operations. The report is not intended to be a thoroughly comprehensive industry guide or study. Rather, it was written as guidance material for those who are seeking general information about the U.S. food-processing industry and its use of technologies and processes that reduce or prevent pollution.

The United States is the largest consumer and producer of "processed" food products in the world. The U.S. food-manufacturing stage is dominated by large-scale, capital-intensive, highly diversified corporations. There are more than 17,000 food manufacturing facilities in the United States. The top 20 manufacturers combined gross more than the next 80 manufacturers and more than the next 101-500 manufacturers in total sales.

The U.S. food-processing industry accounts for approximately 26% of the food-processing output of the world. Food quality standards in the United States are recognized as some of the toughest in the world. The U.S. Environmental Protection Agency (EPA), Food and Drug Administration (FDA), and United States Department of Agriculture (USDA) enforcement agencies have helped ensure a high level of quality and safety for food products to the U.S. consumer. Because the United States is a world leader in food processing, it follows that many of the major technological innovations in the industry, including those in clean technologies and processes, occur in the United States. The term "clean technologies" is defined as "manufacturing processes or product technologies that reduce pollution or waste, energy use, or material use in comparison to the technologies that they replace."

The food-processing industry has special concerns about the health and safety of the consumer. It should be noted that some of the technologies outlined in this report target both human health and environmental pollution issues.

Key resources used by the food-processing industry include the following:

Water. Traditionally, the food-processing industry has been a large water user. Water is used as an ingredient, an initial and intermediate cleaning source, an efficient transportation conveyor of raw materials, and the principal agent used in sanitizing plant machinery and areas. Although water use will always be a part of the food-processing industry, it has become the principal target for pollution prevention, source reduction practices.

Raw Materials. Abundant and productive agricultural sources, conducive climate conditions, and modern technologies are all important factors for providing the U.S. food-processing industry with ample and high quality raw materials. For the most part, food-processing facilities are located close to their agricultural source.

Energy Use. Compared to other industries, for example, metal fabrication and pulp and paper, the food-processing industry is not considered energy-intensive. Facilities usually require electrical power, which is supplied by local utilities, to run food-processing machinery, but fossil fuel use is low to nonexistent.

Key environmental issues for the U.S. industry include the following:

Wastewater. Primary issues of concern are biochemical oxygen demand (BOD); total suspended solids (TSS); excessive nutrient loading, namely nitrogen and phosphorus compounds; pathogenic organisms, which are a result of animal processing; and residual chlorine and pesticide levels.

Solid Waste. Primary issues of concern include both organic and packaging waste. Organic waste, that is, the rinds, seeds, skin, and bones from raw materials, results from processing operations. Inorganic waste typically includes excessive packaging items, that is, plastic, glass, and metal. Organic wastes are finding ever-increasing markets for resale, and companies are slowly switching to more biodegradable and recyclable products for packaging. Excessive packaging has been reduced and recyclable products such as aluminum, glass, and high density polyethylene (HDPE) are being used where applicable.

Clean technologies described in this document include the following:

• Advanced Wastewater Treatment Practices. Use of wastewater technologies beyond conventional secondary treatment.
• Improved Packaging. Use of less excessive and more environmentally friendly packaging products.
• Improved Sensors and Process Control. Use of advanced techniques to control specific portions of the manufacturing process to reduce wastes and increase productivity.
• Food Irradiation. Use of radiation to kill pathogenic microorganisms.
• Water and Wastewater Reduction (Closed Loop/Zero Emission Systems). Reduction or total elimination of effluent from the manufacturing process.

Of these technologies, the ones that the United States is most readily adopting or most likely to adopt in the future include advanced wastewater treatment practices, improved packaging, and water use reduction. Hazard Analysis and Critical Control Point (HACCP) regulations are expected to be fully implemented within the next two to three years and will force a majority of U.S. food-processing companies to improve sanitary conditions further within their facilities. The strengthening of the Clean Water Act (CWA) and concerns over the Resource Conservation and Recovery Act’s (RCRA’s) solid waste disposal issues will continue to drive the industry closer to "sustainable development." Historically, U.S. investments are driven by cost-effectiveness, regulatory mandates, consumer demand, and public interest. This trend is expected to continue as the industry moves into the twenty-first century.

ACRONYMS

2. INDUSTRY BACKGROUND

2.1 Description and History

Many factors working in unison have helped the food-processing industry in the United States become a leader in the domestic and international marketplace. Abundant and productive agricultural sources, along with natural isolation, helped the industry thrive domestically. Competition during the nineteenth century from foreign rivals was minimal due to high transportation costs and continual European conflicts in the late 1800s and early 1900s.

Inexpensive farmland, conducive climate conditions, European agricultural techniques, as well as modern technological advances were all important factors in promoting the supply-side economics of the U.S. agricultural system. The establishment and growth of a middle class in the United States helped create the demand side and economic competition for quality food products. Together, both supply and demand economic factors helped facilitate the success of the U.S. food-processing industry.

Today, the principal global competition in the food-processing industry for the United States comes from Canada, Europe, and South America. The primary growth markets for U.S. products include Asia, Eastern Europe, and South America.

The four food-processing sectors that this report will focus on are (1) fruit and vegetables, (2) meat, poultry, and seafood, (3) beverage and bottling, and (4) dairy operations. All four are spread throughout the United States. Some general discussion of specialty food manufacturing and packaging will be noted but not to the extent of the above sectors.

2.2 Industry Demographics

According to the United Nations’ Centre on Transnational Corporations, the U.S. food-processing industry accounts for approximately 26% of the food-processing output of the world. The U.S. food manufacturing stage is dominated by large-scale, capital-intensive, highly diversified corporations. There are more than 17,000 food manufacturing facilities in the United States. The industry has undergone a consolidation during the past fifty years; in 1947, there were approximately 34,000 food-processing facilities. The four leading sellers of food and tobacco products operate on average 8-9 plants nationwide. The top 20 manufacturers combined gross more than the next 80 manufacturers and more than the next 101-500 manufacturers in total sales.

Table 1 provides a listing of some of the largest companies and organizations for each food-processing subindustry. It is intended to be used as a point of reference, rather than a comprehensive list.

2.2.1 Fruit and Vegetable Food-Processing Sector

The fruit and vegetable food-processing sector in the United States is geographically located around large agricultural producing regions. Before transportation advancements and refrigeration techniques made it possible to ship large amounts of raw material quickly and cheaply, food-processing facilities were constructed close to their agricultural source. Quite simply, it was logical to process and package perishable products close to their agricultural source. Shipping costs and the risk of product spoilage continue to make it advantageous to build facilities near agricultural regions, but it should be noted that processing, preparation, and packaging of fruits and vegetables improve transportability and extend the shelf life of these perishable products.

The primary steps in processing fruits and vegetables include (1) general cleaning and dirt removal, (2) removal of leaves, skin, and seeds, (3) blanching, (4) washing and cooling, (5) packaging, and (6) cleanup. The primary foreign competition comes from other countries in the Western Hemisphere.

2.2.2 Meat, Poultry, and Seafood Sector

In the United States, there are more than 4,000 slaughter and processing plants for the meat, poultry, and seafood sector. These processing plants are, with the exception of seafood plants, located in isolated rural agricultural areas. Sections of the United States with adequate grain supplies and water resources are areas in which livestock-processing plants predominate. Over the past fifty years, facilities have consolidated to incorporate "total" processing capabilities. Rendering and processing have been combined into one facility.

The primary steps in processing livestock include (1) rendering and bleeding, (2) scalding and/or skin removal, (3) internal organ evisceration, (4) washing, chilling, and cooling, (5) packaging, and (6) cleanup. The principal U.S. companies for livestock processing are listed in Table 1. For meat processors, no sizable foreign competition exists in the U.S. market.

2.2.3 Beverage and Fermentation Sector

The soft-drink and brewery companies are controlled by a few large diversified corporations. Both markets have regionalized smaller companies, but for the most part four to five corporations control more than 70% of all sales. This sector follows a system of territorial franchising. Operating facilities are distributed throughout the United States, and geographical areas are not a factor as for fruit and vegetables. Population centers and water resources are the primary location considerations. Accessibility of rail and interstate trucking are also important for facility locations.

The primary steps in processing beverages are (1) raw material handling and processing, (2) mixing, fermentation, and/or cooking, (3) cooling, (4) bottling and packaging, and (5) cleanup. The principal foreign competition for the U.S. brewery sector comes from Europe, Canada, and Mexico and for the soft-drink sector from Canada.

2.2.4 Dairy Sector

The dairy sector can be divided into two basic segments: fluid milk and processed milk products. U.S. dairy production is expected to remain fairly constant in the coming years. Production of fluid milk (with the exception of skim milk) and butter has steadily decreased over the past 10 years, while specialty items like yogurt and ice cream have forged ahead. The number of dairies within the United States has decreased due to consolidation, but the overall level of output has remained constant.

Facilities tend to be located in areas of the United States with traditional European cultural ties to dairy operations as well as adequate grain and water resources. Typically, raw milk is moved by truck to a milk processing center when the processing center is not at the same location as the livestock operation. Fluid milk competition from international sources is almost nonexistent due to fluid milk’s short shelf life, whereas foreign cheese and dry milk product competition comes from Canada, New Zealand, and Europe.

All processed milk products, which include cheese, butter, ice cream, and yogurt, originate from fluid milk. The primary steps in processing are (1) clarification or filtration, (2) blending and mixing, (3) pasteurization and homogenization, (4) process manufacturing, (5) packaging, and (6) cleanup.

2.3 Use of Natural Resources

Water

Traditionally, the food-processing industry has been a large water user. Water is used for several purposes: a principal ingredient, an initial and intermediate cleaning source, an efficient transportation conveyor of raw materials, and the principal agent used in sanitizing plant areas and machinery. Table 2 shows typical rates of water use for various food-processing sectors. An abundant and inexpensive source of water is a requirement for success in the food-processing industry. This coincides with the same need for water resources in agricultural farmland activities.

As mentioned above, the food-processing industry utilizes water to meet its individual day-to-day needs. Fifty percent of the water used in the fruit and vegetable sector is for washing and rinsing. The meat processing sector has minimum requirements set by the United States Department of Agriculture (USDA) on the amount of water required to clean poultry products. Water is the primary ingredient in products for the beverage and fermentation sector, and dairies utilize water as the standard cleaning agent for process machinery.

Although water use will always be a part of the food-processing industry, its reuse and subsequent generation of wastewater have become the principal targets for pollution prevention practices. Water used in conveying materials, plant cleanup, or other noningredient uses are the main areas of potential reduction being considered by the entire food-processing industry.

Raw Materials

Traditionally, food-processing facilities have been located close to their agricultural source. For these facilities, there is usually one chief raw material that makes up the largest percentage of the final food product’s composition. The exception to this is the beverage sector, which is the most similar to a true "manufacturing industry," that is, one in which the product is created from a combination of raw materials. The same can be stated for specialty food products. Confectionery, baked goods, and other luxury products involve much more elaborate manufacturing processes. Typically, specialty food processing uses less water and utilizes base materials that have been preprocessed before they enter their specialty production process.

Energy Use

Compared to other industries, for example, metal fabrication and pulp and paper making, the food-processing industry is not considered energy-intensive. Facilities usually require electrical power, which is supplied by local utilities, to run food-processing machinery, but fossil fuel use is low to nonexistent. In some cases, natural gas is used to operate facility boilers.

2.4 Waste Streams of Concern


All four food-processing sectors within this report view "wastewater" as the primary area of concern. Food-processing wastewater can be characterized as nontoxic, because it contains few hazardous and persistent compounds such as those regulated under the U.S. Environmental Protection Agency’s (EPA’s) Toxic Release Inventory (TRI) listing. With the exception of some toxic cleaning products, wastewater from food-processing facilities is organic and can be treated by conventional biological technologies. Part of the problem with the food-processing industry’s use and discharge of large amounts of water is that it is located in rural areas in which the water treatment systems (i.e., potable and wastewater systems) are designed to serve small populations. As a result, one medium-sized plant can have a major effect on local water supply and surface water quality. Large food-processing plants will typically use more than 1,000,000 gallons of potable water per day.

Wastewater

The five-day biochemical oxygen demand (BOD₅) value is used as a gauge to measure the level of treatment needed to discharge a wastewater safely to a receiving water. The BOD for all food-processing wastewater is relatively high compared to other industries. A high BOD level indicates that a wastewater contains elevated amounts of dissolved
and/or suspended solids, minerals, and organic nutrients containing nitrogen and phosphorus. Each one of these constituents represents a particular contaminant of concern when discharging a wastewater.

Publicly owned treatment works (POTW) that receive food-processing wastewater with BOD₅ values greater than 250 to 300 mg/L typically will add an additional surcharge for treatment. Any company is subject to fines by either the state and/or federal environmental enforcement agency when they are discharging to a receiving water and exceeding their permitted BOD₅ discharge level. In the past, wastewater disposal costs were a minor operating expense. In today’s climate, due to increased enforcement of discharge regulations and escalating POTW surcharges, many food-processing facilities are taking steps to either reduce, recycle (or renovate), and/or treat their wastewaters before they discharge them.

Another contaminant of food-processing wastewaters, particularly from meat-, poultry-, and seafood-processing facilities, is pathogenic organisms. Wastewaters with high pathogenic levels must be disinfected prior to discharge. Typically, chlorine (free or combined) is used to disinfect these wastewaters. Ozone, ultraviolet (UV) radiation, and other nontraditional disinfection processes are gaining acceptance due to stricter regulations on the amount of residual chlorine levels in discharged wastewaters.

The pH of a wastewater is of paramount importance to a receiving stream and POTW. Biological microorganisms, used in wastewater treatment, are sensitive to extreme fluctuations in pH. Companies that are found to be the responsible polluter are fined and/or ordered to shut down operations until their pH level meets acceptable values. Wastewater discharge values that range from 5 to 9 on the pH logarithmic scale are usually acceptable. Low pH values are more damaging to a receiving stream and POTW biological treatment process.

Solid Waste

Solid waste from food-processing plants are especially high in nitrogen and phosphorus content. Most solid wastes can be processed into valuable byproducts that are resold as fertilizer, animal feed, and other useful products. A past barrier to byproduct resale has been converting the byproduct into useful, marketable material. The addition of coagulants to food-processing wastewaters makes much of the solid waste sludge unsuitable for animal feed. If a receiving company would not take the untreated byproduct waste "as is," the food processor was responsible for converting it into a useful product for sale. Typically, this was not done, and the solid waste was disposed of by conventional means. A growing trend (see sections 4 and 5) is the principle of "zero emissions," which relies on a network of companies utilizing one company’s waste streams as another company’s raw materials.

Air Emissions

Air emissions are not a major concern for the food-processing industry. With the exception of breweries, most operations emit low process air emissions. Most operations typically utilize electric power and rarely emit harmful compounds to the environment during normal production operations. Air emissions from biological treatment processes have become an area of concern, but a relatively minor one compared to wastewater issues.

2.4.1 Fruit and Vegetable Waste Streams

Wastewater and solid wastes are the primary area of pollution control within the fruit and vegetable food-processing industry. Their wastewater is high in suspended solids, and organic sugars and starches and may contain residual pesticides. Solid wastes include organic materials from mechanical preparation processes, that is, rinds, seeds, and skins from raw materials. For the most part, solid waste that is not resold as animal feed is handled by conventional biological treatment or composting. The total amount of material generated is a function of the amount of raw material moved through a facility, for example, for a given weight of apples processed comes a set amount of peel and seed waste.


The fruit and vegetable sector is seasonal for a majority of products, and the wastewaters vary according to the specific raw material being processed. Some larger facilities retool each season and, therefore, handle several different types of foods. Attempts to decrease solid waste streams have not been an area of great development for pollution prevention opportunities and clean technologies. Pretreatment opportunities intended to reduce the amount of raw materials lost to the waste stream have been an area of clean technology development. For the most part, the majority of clean technology advances and research have been in reducing the volume of wastewater generated in food-processing operations. Wastewater generation has been directly correlated to total waste load (i.e., pounds, not concentration).

Most fruit and vegetable processors use traditional biological means to treat their wastewater. Advancements in the degradation chemistries of pesticides have aided in reducing their quantities and toxicity in process wastewater.

2.4.2 Meat-, Poultry-, and Seafood- Processing Waste Streams

Meat, poultry, and seafood facilities offer a more difficult waste stream to treat. The killing and rendering processes create blood byproducts and waste streams, which are extremely high in BOD. These facilities are very prone to disease spread by pathogenic organisms carried and transmitted by livestock, poultry, and seafood. This segment of the food-processing industry is by far the most regulated and monitored. Inspectors for the Food and Drug Administration (FDA), USDA, EPA, and local health departments all keep a watchful eye on meat, poultry, and seafood facilities.

Waste streams vary per facility, but they can be generalized into the following: process wastewaters; carcasses and skeleton waste; rejected or unsatisfactory animals; fats, oils, and greases (FOG); animal feces; blood; and eviscerated organs. The primary avenue for removal of solid waste has been its use in animal feed, cosmetics, and fertilizers. These solid wastes are high in protein and nitrogen content. They are excellent sources for recycled fish feed and pet food. Skeleton remains from meat processing are converted into bonemeal, which is an excellent source of phosphorus for fertilizers. FOG waste (typically from industrial fisheries) is used as a base raw material in the cosmetics industry.

2.4.3 Beverage and Fermentation Waste Streams

Wastewater and solid waste are the primary waste streams for the beverage and fermentation sector. Solid wastes result from spent grains and materials used in the fermentation process. Wastewater volume of "soft drink processes" is lower than in other food-processing sectors, but fermentation processes are higher in BOD and overall wastewater volume compared to other food-processing sectors.

2.4.4 Dairy Waste Streams

A majority of the waste milk in dairy wastewaters comes from start-up and shut-down operations performed in the high-temperature, short-time (HTST) pasteurization process. This waste is pure milk raw material mixed with water. Another waste stream of the dairy sector is from equipment and tank-cleaning wastewaters. These waste streams contain waste milk and sanitary cleaners and are one of the principal waste constituents of dairy wastewater. Over time, milk waste degrades to form corrosive lactic and formic acids. Approximately 90% of a dairy’s wastewater load is milk.

3. ENVIRONMENTAL ISSUES AND REGULATIONS

Federal environmental regulation (i.e., EPA) combined with FDA and USDA have helped ensure a high level of quality and safety for food products for the consumer.

EPA and state governments enforce environmental issues pertaining to the food industry, whereas FDA and USDA enforce health issues. These health organizations have a greater effect than environmental regulations on the way business is done in the food-processing industry.

FDA is part of the U.S. Public Health Service and is responsible for ensuring the safety and wholesomeness of all foods sold in the United States except for those under the purview of USDA. FDA’s authority includes all alcoholic beverages under 7% alcohol level, dairy products, and seafood products.


USDA enforces standards for wholesomeness and quality of fruits, vegetables, meat, poultry, and eggs produced in the United States. USDA enforces these standards through inspections of all facets of the production of food products. USDA issues its approval before such items can be sold to the U.S. consumer. FDA is part of the U.S. Public Health Service and is responsible for ensuring the safety and wholesomeness of all foods sold in the United States except for those under the purview of USDA. FDA’s authority includes all alcoholic beverages under 7% alcohol level, dairy products, and seafood products. The Bureau of Alcohol, Tobacco, and Firearms (ATF) handles alcoholic beverages greater than 7% total alcohol. These agencies work with state and local governments to ensure the quality and safety of food produced within their jurisdictions.

Environmental Standards

Various federal environmental regulations and statutes, such as the Federal Water Pollution Control Act or the Clean Water Act (CWA), Clean Air Act (CAA), Pollution Prevention Act (PPA), and Resource Conservation and Recovery Act (RCRA), have changed the way processing facilities handle food products and dispose of their waste.

The CWA’s increasingly stringent regulations for discharging wastewater are the primary regulatory drivers for the food-processing industry. RCRA regulations typically apply only to solid waste disposal issues, and the Superfund’s Emergency Planning Community Right-to-Know Act (EPCRA) has had only minor impact on the hazardous material handling and waste generation practices of the food-processing industry.

During the 1990s, pollution prevention (P2) and clean technologies have come to the forefront in reducing and controlling the environmental effects created by food-processing facilities. The policy set forth in the PPA of 1990 outlines a systematic approach for efficiently reducing pollution. The following is a passage from this act:

. . . pollution should be prevented or reduced at the source whenever feasible; pollution that cannot be prevented should be recycled in an environmentally safe manner, whenever feasible; pollution that cannot be prevented or recycled should be treated in an environmentally safe manner whenever feasible; and disposal or other release into the environmental should be employed only as a last resort and should be conducted in an environmentally safe manner.

Most federal and state regulations and statutes are typically met with resistance from private industry. Conversely, the PPA’s pollution prevention principles and the subsequent development of clean technologies have been viewed as ways to provide cost savings and sometimes even improve product quality, while simultaneously improving public relations for companies and industries that aggressively pursue their implementation. Pollution prevention has proved to be an effective means of reducing compliance and treatment costs for food-processing manufacturers.

Pollution prevention and clean technologies are meant to focus on a multimedia (i.e., air, water, and land) approach to reducing waste. As mentioned earlier, air emissions from wastewater treatment activities are not a major source of concern for the food-processing industry. Solid waste and, more important, wastewater discharges, however, tend to dominate activity for implementing pollution prevention advances. Unless located in a remote area, most food-processing facilities pretreat and discharge wastewater directly to a POTW. When a facility discharges to the environment, they are required to have a National Pollutant Discharge Elimination System (NPDES) permit as mandated in the CWA.

EPA is looking for several ways to promote voluntary pollution prevention. The PPA lacks the regulatory powers needed to force companies to implement pollution prevention practices into their production processes. Agencies are exploring ways to write more flexible permits to allow companies to make process changes without having to resubmit a lengthy permit modification. Environmental agencies are encouraging pollution prevention by doing such things as reducing the cost of a permit or extending the compliance schedules for companies that are proactive in pollution prevention practices.

Health Standards

USDA’s Food Safety and Inspection Service (FSIS) has issued a new set of rules for poultry and meat processors. The new procedures are the first stage of the implementation of USDA’s final rule on Pathogen Reduction: Hazard Analysis and Critical Control Point (HACCP) Systems, also known as the "Mega-Reg." HACCP regulations replace an inspection system based on sight and smell with scientific methods that require meat-processing facilities to reduce harmful pathogens and bacteria. HACCP will be phased in slowly because of debate on how it should be accomplished. The changes will also include new regulations for seafood facilities. Previously, seafood products were not regulated by USDA, but by FDA.


The new rules require processing facilities to develop a written set of sanitation standard operating procedures (SSOPs) and inspect their plants every day to ensure that pre-operational sanitary conditions are met. Poultry slaughter plants are required to check samples for E. coli every eight-hour shift. Results of these inspections and the written SSOPs must be available to USDA inspectors. Corrective action against failed inspections can range from on-the-spot cleanups to possible shut-down of operations until the facility meets the requirements of HACCP.

4. CLEAN TECHNOLOGY DEVELOPMENTS

Because wastewater generation is the industry’s biggest area of concern, the following clean technologies focus on source reduction, recycling, reuse, and treatment of wastewater. Clean technologies are defined in this report as "manufacturing processes or product technologies that reduce pollution or waste, energy use, or material use in comparison to the technologies that they replace."

The food-processing industry has special concerns about the health and safety of the consumer. It should be noted that some of the technologies outlined in the report target both human health and environmental pollution issues.

Common source reduction methods employed at most plants include improving good housekeeping practices, making process modifications, substituting more environmentally friendly raw materials, and segregating waste streams. Some simple cost-effective means of achieving source reduction include installing automatic shut-off valves, using low-flow or air-injected faucets/spray cleaners, switching from chemical caustic peeling processes to mechanical peeling, and converting from water to mechanical conveyance of raw materials through a production line. Resources for implementing some of these processes and products are listed in Table 3.

4.1 Advanced Wastewater Treatment Practices

Description. Advanced wastewater treatment is defined as any treatment beyond secondary (or biological) treatment. These treatment practices are employed to target specific discharge constituents that are of concern. Typically, pathogens, suspended solids, dissolved solids, nitrogen, and phosphorus are removed in advanced wastewater treatment. The following is a listing of some technologies being used in advanced wastewater treatment.

• Membrane applications
• Disinfection
• Charge separation
• Other separation practices.

Membrane applications focus on separating water from contaminants, using semipermeable membranes and applied pressure differentials. In generic terms, they work like window screens that let air but not insects and other larger objects pass through. The smaller the screen holes, the smaller the objects need to be to pass through. Pressure is applied to reverse the natural equilibrium between the clean water and wastewater. The basic principle of natural equilibrium is that the clean water tends to migrate to the wastewater side to equalize the concentrations across the membrane. Mechanical pressure is used to force water molecules from the wastewater side to the clean water side and, thus, a "high-tech" filtration of the wastewater occurs. In the past, the energy needed to apply the pressure and the fragility of the membrane surface made use of these alternatives economically unjustifiable.

There are varying degrees of membrane filtration. Microfiltration, ultrafiltration (UF), and reverse osmosis (RO) are the current membrane systems used commercially. The filtering capabilities of each (i.e., ability to filter based on contaminant particle size) decreases respectively. Microfiltration is only recommended for removing particles from 0.05 to 2 microns in size, UF is used for particles and suspended solids from 0.005-0.1 microns, and RO is used for particles, suspended solids, and dissolved solids in the Angstrom range (e.g., molecular weight above 200).

Problems with membrane applications include biofouling of the membrane and fragility of the membrane surface. Toxic synthetic compounds can oxidize the surface of the membrane, thus, destroying it. New innovations in membrane technology have advanced the "cleanability" and reuse of membranes. The use of stainless steel and ceramic materials for membranes has greatly improved their use in advanced wastewater treatment.

Sanitary conditions have always been a concern for food products created in the manufacturing process.

In recent years, they have also become a requirement of wastewater effluent. As for water treatment practices, disinfection through chlorination has been the quickest means of disinfecting wastewater. Disinfection has come under criticism due to chlorination byproducts and toxicity concerns that residual chlorine pose to aquatic life. The two principal means of disinfecting wastewater without using chlorination are ozone disinfection or UV disinfection. Ozonation works on the same principle as chlorination but leaves no residual in the treated wastewater and does not produce the magnitude of disinfection byproducts that chlorination produces. UV disinfection is even more environmentally friendly than ozone but requires more space and cleaner wastewater to be effective. Both technologies require high capital and operating costs.

Charge separation involves separating uncharged water molecules and charged contaminants, such as nitrogen compounds, and phosphates (i.e., NH₄⁺, NO₂^-, NO₃^-, and PO₄^-3). Electro-coagulation is starting to be an economical way of removing charged particles from wastewater, utilizing charge separation. Ion exchange is widely used to filter wastewater through cationic and anionic resins to remove the wastewater’s charged ions of concern. Ion exchange replaces the waste particles with a donor ion from the resin. The resins eventually reach a capacity at which all the ions have been replaced or exchanged. Spent resin is typically recycled by the resin manufacturer. Problems with using ion exchange are that it requires monitoring for breakthrough contamination and pH fluctuations can greatly affect the removal rates of specific ions (e.g., a pH greater than 9.3 makes ammonium removal inefficient). Also, resins remove ions selectively, meaning the greater the charge differential from neutrality, the greater the exchange attraction between the resin and the charged contaminant (e.g., Ca⁺² will be removed before NH₄⁺).

Other separation practices include using centrifugal and gravity mechanisms to separate and remove contaminants from a wastewater. Air flotation systems use diffused pumped air to lift suspended solids and FOG wastes to the surface of a wastewater for removal. Skimmers and mechanical devices are then employed to separate waste from the surface. Problems with using either of these methods include capital costs to modify current treatment processes, and increased operational energy costs.

With the exception of centrifugal and gravity separation, all these advanced treatments require a wastewater influent that is low in turbidity.

Benefits. Studies have shown that membrane applications can be less energy intensive than evaporation and distillation operations and take up less space. The technology gives better control of the process effluent. Unlike chemical precipitation, membrane technology does not produce a sludge disposal problem, but it does produce a concentrated brine solution.

The main benefit of disinfecting wastewater is that it improves and protects water quality of and aquatic life in the receiving water. Similar to membrane applications, ion exchange does not produce a chemical sludge and, like disinfection, it protects the water quality of a receiving water and decreases the nutrient-loading problems that cause eutrophication in receiving waters.

Electro-coagulation is beginning to receive attention as a treatment option and is expected to increase in use in the food-processing industry.

Centrifugal and gravity separation processes are placed before any of the preceding advanced operations. This ensures that a cleaner, less turbid wastewater reaches these advanced operations. As stated earlier, the recovered FOG is a resalable byproduct. Use of any of these advanced processes improves the final wastewater effluent quality and also increases the likelihood of recycling a renovated process water.

Status of Use in the United States. The number of food-processing facilities using advanced treatments has nearly tripled in the past 10 years. This trend is expected to continue because of increasing restrictions on wastewater discharge from federal and state agencies. The strengthening of the CWA provides an incentive to utilizing these advanced wastewater treatments.

4.2 Improved Packaging

Description. Solid waste disposal, decreasing available landfill space, and consumer pressure have caused food-processing manufacturers to reevaluate their use of packaging. Excessive packaging has contributed to an overabundance of solid waste and an ever-growing dilemma of what to do with it. In 1970, typical tipping fees for solid waste disposal were US$0.75/ton. Today, costs may reach US$100 to US$200/ton. By 2000, those figures are expected to rise to US$500/ton in some areas of the country.

The Steel Recycling Institute (SRI) and the National Solid Wastes Management Association (NSWMA) reported that recycling of common industrial packaging has increased dramatically. In 1988 only 15% of all steel cans produced were recycled. In 1992, 41% of all steel cans were recycled; this number has increased by approximately 20% since that time. According to NSWMA, almost 95% of all steel cans produced are for food and beverage operations.

Recent in-house packaging changes at Tyson Foods and other food manufacturers have included use of plastic liners in corrugated boxes within a plant, use of high density polyethylene (HDPE) plastic totes, and substitution of foam food-packaging containers for ones made from materials free of chlorofluorocarbons. Tyson Foods has also created an incentive program to get feedback from employees on how to reduce packaging. One change that was implemented was redesign of an entrée dinner dish that saved approximately 1,175,289 pounds of packaging per year.

In the past ten years, consumers have demanded more environmentally friendly packaging. Public pressure has even reached the fast-food industry. For instance, McDonalds has greatly reduced the use of styrofoam in their food products. Food packaging suppliers, however, agree that until public pressure or federal regulation mandates new packaging materials and techniques, the industry will continue to remain "customer" driven. Packaging suppliers state that they do not sell to a consumer, but rather to the people that sell to the consumer. As a result, it is difficult for a packaging company to come up with new and innovative products because they first have to convince food processors that consumers will like the packaging changes.

Benefits. In some cases, the benefit of changing packaging is lower costs, but, in most cases, the cost is either the same or slightly more. Typically, it is only advantageous to change packaging from a "goodwill" standpoint. Food manufacturers who effectively advertise their packaging as more environmentally friendly quickly gain an advantage over their competition and improve their public relations image.

Additional benefits from implementing packaging changes are decreasing the ultimate solid waste disposal amount and decreasing possible future liabilities that a package might cause, that is, leaching problems in landfills.

Status of Use in the United States. Both federal and state regulations are directed at landfill owners and operators but will affect food companies down the line as disposal restrictions prohibit and/or increase costs for wastes being landfilled. Food-processing companies are slowly switching to more biodegradable packaging products. Excessive packaging has been reduced and recyclable products such as aluminum, glass, and HDPE are being used where applicable.

4.3 Improved Sensors and Process Control

Description. Automation is being used more frequently in the food-processing industry. In the past, concerns about reliability and high capital cost slowed the technology transfer of automated machinery to the food-processing industry. Improvements in technology and reductions in costs have now made analytical sensors, PC interfaces, and closed-loop control systems more attractive. These types of automated products allow the user to improve efficiency, control the process of raw material inputs, and control the amount of wastes generated. Sensors can be used to control process temperature, humidity, pH, flow rates, and contamination levels.

Automation has been used for years in the specialty, beverage, and dairy sectors, but, until recently, it has not been used to a great extent in the fruit-, vegetable-, and meat-processing sectors. The technology has advanced to the point that computers can now be used for assessing conditions that, in the past, only workers could assess. Artificial intelligence was the phrase coined in the 1980s to describe the capabilities of these new pieces of equipment. Sensors are capable of characterizing physical properties of processing materials. Subjective properties, such as appearance, taste, aroma, and texture as well as physical properties such as size, shape, texture, and color, are all possibilities for automated assessment.

Benefits. Use of automation further reduces the chance of human error in manufacturing processes. Automation improves speed and accuracy in measuring process variables and also reduces labor costs. Through the use of automation, workers can dedicate their time to other more pressing production issues. Automated equipment makes real-time data available to plant personnel without interrupting the production run.

Status of Use in the United States. A majority of facilities in the United States are operating their production lines with outdated equipment. As with other aspects of the food-processing industry, only when industry realizes the economic benefits of a clean technology investment, will they convert. A new wave of cost-effective automated products is continuing to become available, but the best chance of implementing these types of technologies is when building new facilities. Bottlenecks and other problems are less likely to occur, and management is more open to utilizing new technologies during a facility’s early design phase.

4.4 Food Irradiation

Description. Food irradiation involves applying low-dose radiation to fruits, vegetables, meats, and other food products. Irradiation kills deadly foodborne-illnesses such as E. coli, salmonella, and other harmful pathogens. The irradiation process extends the shelf life of food products and can change rejected meat products into approved products by killing the pathogens that caused them to fail. Also, low-dose radiation inhibits sprouting or ripening of food products.

There are drawbacks to using this technology. The public is wary of applying radiation to consumable food products, and irradiation does not kill or breakdown harmful toxins that are left on food products. Concerns about taste and reduced nutritional value have for the most part proved unwarranted, but application of the radiation dose may taint some pork products if they are at a high temperature when irradiated.

Benefits. Using food irradiation can decrease the water needed for rinsing and cleaning food products and decreases the chances of pathogens tainting the products. The cost for irradiation is low (on the order of pennies per pound) and takes a relatively short exposure time to kill the pathogens of concern. Critics say food processors and food service operators are looking to irradiation as an "easy way out" of stringent adherence to HACCP procedures.

Status of Use in the United States. Currently, there are no irradiation chambers in food-processing plants. Foods are transferred to commercial irradiation sites for application. Food that is irradiated must be labeled as such, and most food-processing companies are hesitant to sell their products with such labeling. Further scientific studies will be needed if irradiation is to be used up to its potential. U.S. public perception is not favorable, but the forecast for food irradiation is that it will gain in acceptance within the next 10 years.

4.5 Water and Wastewater Reduction (Closed Loop/Zero Emission Systems)

Description. An increasingly viable option for companies is the "zero-discharge" system. Many food-processing facilities are looking to pretreatment options that can help reduce the amount of lost product. Once a part of the food product is lost to a waste stream, it represents a decrease in product utilization and an increase in treatment costs. A large capital expenditure and a customized treatment solution are required to handle a zero-discharge option. Furthermore, the uniqueness of the various food-processing operations makes it impossible to find "off-the-shelf" treatment designs to fit a user’s needs.

A more plausible approach is that of achieving zero emissions. As noted earlier, the "zero emissions" strategy relies on a network of companies utilizing each other’s waste streams. The strategy is a more economically efficient system than a "closed loop" because the waste products do not have to be fully treated. Although facilities are moving toward decreased effluent quantities, material mass balances still dictate that process residuals such as sludges will require management and possibly off-site disposal.

Benefits. Both zero discharge and zero emission systems achieve better effluent water quality and have fewer negative impacts on the environment.

Status of Use in the United States. A zero discharge or emission facility is a lofty goal. U.S. industries are moving toward such goals but it would be unrealistic to have a total zero discharge. Through regulation and other restrictions, the U.S. food-processing industry is expected to invest more time, money, and effort in reducing effluent levels and contamination to the lowest economically feasible levels. Market consolidation and improved communication among companies will help foster the principle of "one company’s waste is another’s raw material."

5. FUTURE TRENDS

Regulations and Standards

The U.S. food-processing industry will continue to prosper in the foreseeable future. Industry standards and business practices will continue to be driven by both regulatory mandates and consumer taste. The HACCP regulations are expected to be fully implemented within the next two to three years, which will require a majority of U.S. food-processing companies to further improve sanitary conditions within their facilities. The strengthening of the CWA and concerns over RCRA’s solid waste disposal issues will continue to drive the industry closer to "sustainable development" principles of waste reduction, and recycling.

International standards developed by the Geneva-based International Organization of Standardization, called ISO 14000, represent the latest attempts to provide a global environmental management system. ISO 14000 was intended to help organizations manage and evaluate the environmental aspects of their operations without being prescriptive. The International Organization of Standardization intends to provide companies with a framework to comply with both domestic and foreign environmental regulations. ISO 14000 contains sections calling for implementation of pollution prevention programs, and many U.S. companies are evaluating the pros and cons of becoming fully certified in ISO 14001. Furthermore, EPA is talking about easing reporting requirements for U.S. companies that earn ISO 14001 certification.

Industry Trends

There are several ongoing trends and research and development activities apparent within the food-processing community in the areas of pollution prevention and clean technology implementation.

Solid Waste Reduction. Companies will continue to look at ways to reduce solid waste generation, use less or reusable packaging, and use biodegradable packing products. Excessive packaging has been reduced and recyclable products such as aluminum, glass, and HDPE are expected to continue being used to a wider degree in packaging situations.

Mechanical Versus Chemical Processing. Companies will show increased consideration for using mechanical methods for food processing (e.g., the fruit and vegetable sector). Mechanical processing can be used to perform many of the same functions as chemical processing. The costs and benefits of using mechanical versus chemical processing will be further quantified to aid in decision making.

Pretreatment Options, Water Conservation, and Wastewater Reduction. Pretreatment opportunities and water conservation will continue to be principal targets for pollution prevention source reduction practices in the food-processing industry. Pretreatment options look to minimize the loss of raw materials to the food-processing waste streams. Water used in conveying materials, facility cleanup, or other noningredient uses will be reduced, which in turn will reduce the wastewater volume from food-processing facilities. Wastewater treatment will continue to be the pollution prevention treatment focus for food-processing companies. The industry will continue to implement advanced innovative techniques to lessen the environmental impact of food-processing discharge wastewaters.

To succeed, the U.S. food industry will have to continue to juggle the demands of consumers, investors, environmental compliance, as well as competitiveness of both the domestic and global marketplaces.


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Selected publications of:
Pacific Northwest National Laboratory: State-of-the-Art Report(s)

National Center for Food Safety & Technology (NCFST)

U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition

U.S. Department of Agriculture, Food Safety and Inspection Service: Background Papers
The 1996 National Poultry Waste Symposium proceedings

North Carolina Cooperative Extension Service: Water Quality & Waste Management Reports