Jump to main content.

Effluent Guidelines

Pollution Prevention (P2) Manual Logo

Chapter 3: Pollution Prevention Glossary

Glossary of the specific P2 practices and equipment required to implement the P2 alternative, as well as other P2 practices and equipment found in the industry, including illustrations and benefits of use.

 

Pollution Prevention Practices

Pollution Prevention Equipment

Many PFPR facilities use P2 practices that conserve water, reduce the amount of pollutants in wastewater, or eliminate wastewater generation altogether. This chapter presents alphabetic glossaries for two basic types of P2 techniques: (1) implementation of P2 practices; and (2) use of P2 equipment. For the P2 practices, a description of the practice and its benefits and an icon representing the practice are provided. For the P2 equipment, a picture or illustration and description of the equipment is provided. Throughout the manual, terms defined in this glossary will be shown in italicized bold print.

The techniques presented in this chapter have been identified through site visits to almost 60 PFPR facilities, where EPA observed the techniques in use. By implementing these P2 techniques (e.g., use of flow reduction equipment), many PFPR facilities generate less wastewater volume. By controlling the volume of wastewater generated, facilities can often reuse a larger overall percentage of their wastewater. Additionally, facilities can achieve opimal P2 benefits by combining P2 techniques (e.g., use of flow reduction equipment, dedication of equipment, and interior storage and reuse) to reduce or eliminate wastewater generation and to increase the level of reuse and recycle. [Note: This P2 glossary presents not only those practices listed in Table 8 of the final PFPR rule, but also other P2 techniques that were observed in the industry.]

P2 Practices

These practices reduce the amount of active ingredients and other raw materials lost in wastewater discharges, and may also decrease the volume of PFPR process wastewater generated.



Pollution Prevention Practices

Dedication of Equipment

PFPR facilities use production lines to formulate, package, and repackage a wide range of products. When switching a production line from one product to another (i.e., product changeover), the facility cleans the equipment (typically with water) to prevent cross-contamination of products. Dedicating equipment on formulating and/or packaging lines to the production of one product or product type can reduce or eliminate the need to clean that piece of equipment for product changeover. In addition, because of the elimination of cross-contamination concerns, routine cleaning typically uses less water.

Some facilities dedicate just their formulation tanks, thereby eliminating one of the most highly concentrated wastewater streams generated at their facility. Other facilities have dedicated storage tanks or entire formulating, packaging, or repackaging lines, if they produce large quantities of that product over long periods of time. Still other facilities dedicate transfer hoses, pumps, and other miscellaneous equipment. These PFPR facilities have implemented this practice by using equipment that is:

 

Direct Reuse of Drum Rinsate

PFPR facilities frequently receive raw materials in drums, such as 55-gallon steel or 30-gallon fiber drums. Empty drums may be returned to the supplier, or the facility may by responsible for disposal. To prepare the drums for reuse, facilities "triple rinse" the drum (i.e., rinse out the inside of the drum with water three times) or pressure rinse the drum according to procedures provided in 40 CFR, Part 165. A "triple rinse" is defined in Part 165 as flushing the container three times, using a volume of the diluent equal to approximately 10% of the container's capacity. When preparing drums for disposal that contained nonhazardous materials, facilities should consult 40 CFR, Part 165.9 to determine if a triple rinse is required.

If the drum contained a material that is a listed hazardous waste, facilities must also follow procedures provided in 40 CFR, Part 261.7(b) to empty the container and dispose of or recycle it as nonhazardous. For example, "U" listed wastes (40 CFR, Part 261.33(f)) must be removed so that no more than 2.5 centimeters (or one inch) of residue remains on the bottom of the container, no more than 3% by weight of the container capacity remains in containers less than or equal to 110 gallons, and no more than 0.3% by weight of the container capacity remains in containers larger than 110 gallons. It may not be necessary to rinse the container if the material can be sufficiently removed by draining, pouring, pumping, or aspirating, unless rinsing is required by 40 CFR, Part 165. Other wastes, such as "P" listed wastes (40 CFR, Part 261.33(e)), must be removed by triple rinsing the container using a solvent capable of removing the material.

The simplest, most cost-effective method of handling the subsequent rinsate is to reuse it directly in the product formulation at the time of formulation. This method eliminates the water from the facilitys waste stream and recovers the remaining raw material in the drum without the costs and space needed for storage of the rinsate. If the product is a solvent-based product, the drums can be rinsed with the base solvent of the product instead of water to prevent creating a rinsate that cannot be added directly to the formulation.

In addition to reusing rinsate, some PFPR facilities use flow reduction equipment, such as high-pressure washers, to effectively clean drums, while minimizing the amount of rinsate generated (generally 5 to 15 gallons of rinsate per drum).

Formulating and Packaging Small Batches in Containers

Facilities that generate small quantities of product may formulate that product directly in the final shipping container (e.g., 55-gallon drum or minibulk tank) to eliminate the use of a separate formulation tank. Facilities may also package products directly from the formulation tank or blender into the final shipping container to eliminate using interim storage tanks, packaging tanks, and transfer hoses. These practices eliminate the need to use and clean certain formulating and packaging equipment, thereby reducing the amount of rinsates generated during cleaning.

Good Housekeeping Practices

Good housekeeping practices are simple, straightforward operating practices that can significantly reduce wastes. These practices include performing preventive maintenance on all valves, fittings, and pumps; placing drip pans under valves and fittings where hoses or lines are routinely connected and disconnected; and cleaning up spills and leaks in outdoor bulk storage and process areas to prevent contamination of stormwater or exterior rinsewaters. Other goo housekeeping practices include repairing leaky valves and fittings in a timely manner and reusing the material collected in drip pans.

Interior Rinsate Storage and Reuse

PFPR facilities use production lines to formulate, package, or repackage a wide range of products. When switching a production line from one product to another, the facility cleans the equipment (typically with water) to ensure product quality. This interior equipment rinsate (either water or base solvent) can be collected and stored in 55-gallon drums or small tanks for reuse as make-up water in the next batch of that formulation or a compatible formulation (e.g., product with same ingredients but at varying concentrations). In some cases, the rinsate can be reused immediately in the product if additional water or solvent is needed for the final product (e.g., refilling establishments preparing the product for application on fields).

When facilities combine this practice with the use of flow reduction equipment, dedication of equipment, and other production practices, they can minimize the volume of rinsates generated during production of pesticide products and are often able to reuse all interior equipment cleaning rinsates. Benefits from these practices include reduced costs for raw materials and waste disposal or treatment.

Inventory Management

Many PFPR facilities operate inventory management systems to track raw materials, finished products, and waste products. These systems are also useful for tracking cleaning rinsates that can be reused at a later date in product formulations. Some facilities log these rinsates into their inventory as raw materials to ensure reuse as soon as possible and to eliminate the possibility of forgetting about them once they are stored. In addition, quick reuse can reduce shelf-life expiration problems. These inventory systems may be manual (for smaller operations) or computerized (for larger operations), and may also contain other environmental data, such as waste disposal information.

Non-Water Interior Equipment Cleaning

PFPR facilities can use several cleaning techniques in addition to dry process cleaning equipment to reduce or eliminate wastewater generation. After formulating or packaging, dry carriers used in the final product (e.g., clay) are often used to initially clean the equipment. These materials are run through the equipment to absorb residual product that may be present and stored for use in a future batch of that product. A production line may also be "blown" clean by forcing air through the equipment and collecting the material that exits the system for reuse. Hoses and transfer piping may be cleaned in this manner. A water rinse may follow this procedure. Cleaning a line with dry materials increases recovery of raw materials and reduces the amount of water used during cleaning operations.

Operation of Air Pollution Control Devices

Air pollution control devices, including baghouses, cyclones, filters, and wet scrubbers, are sometimes installed on formulating or packaging lines to control the release of volatile or dust emissions.


 

Operation of Department of Transportation (DOT) Test Baths

DOT test baths are used to test aerosol cans for leaks or weaknesses under pressure. The cans are visually examined for leaks while in the test bath. Because drips on the outside of cans, or occasionally exploding cans, can contaminate the water bath, the water in batch baths must be changed periodically to ensure visibility and to reduce the presence of residues that may adhere to cans leaving the bath. Facilities operating DOT test baths with continuous overflow can recirculate the water for reuse. If necessary for visual clarity, PFPR facilities can recirculate the water through a filter (e.g., diatomaceous earth or activated carbon) to remove dirt and oils. The use of filters allows water to be recirculated for longer periods of time before changeout is necessary.

Production Scheduling

If a facility is not able to practice dedication of equipment, they often can manage their production schedules to minimize product changeover cleaning operations. To do so, facility personnel can develop cleaning procedures specific to each potential changeover. They can examine which products can be formulated in succession without the need for cleaning (e.g., they contain the same ingredients but in varying concentrations) or with a minimal cleaning. On any given day, production can be scheduled to minimize the cleaning efforts and therefore the wastes that are generated during cleaning. In some cases, facilities are able to schedule production so that the cleaning rinsates generated are able to be reused in subsequent processes.

Training and Written Standard Operating Procedures

Employee training and well-written standard operating procedures (SOPs) are an integral part of any pollution prevention program. Training will ensure that all employees are aware of the goals of current pollution prevention initiatives and how the initiatives will improve operations. Written SOPs will reinforce operator training and ensure that all functions are performed efficiently. It is important to obtain both management and employee buy-in to the program, and to view pollution prevention as a way of doing business. Some PFPR facilities have formed pollution prevention teams or coordinators to develop SOPs for cleaning procedures and for reuse of cleaning rinsates into formulations. Some facilities have also integrated an evaluation of an employees adoption of P2 practices into performance reviews or provided awards or incentives for innovative P2 ideas.

Pollution Prevention Equipment

Drum Rinsing Station

A drum rinsing station consists of a series of three cells that are used to triple rinse drums. A typical station uses a spray nozzle to shoot water at high pressure into a drum that is inverted over the cell. The rinsate flows out of the drum into the cell, the drum is moved to the next cell, and the process is repeated. The first cell is used for the first rinse, which results in the most removal of pollutants and the most contaminated rinsewater. The second cell is used for the second rinse, which removes additional pollutants, but the rinsewater is not as contaminated as the first cell. The third cell is used for the final rinse, at which point most of the pollutants have been removed by prior rinses and the rinsewater is the least polluted of the three cells.

By rinsing the drum in stages (i.e., cells), the volume of rinsewater is reduced. The rinse water in the first cell is reused until it is visibly too contaminated to be used further. At that time, it is removed from the cell and treated or disposed of. The cleaner rinsewater from the second cell is transferred into the first cell and the cleanest rinsewater from the third cell is moved to the second cell. Fresh water is added only to the third cell. As a result, two cells of water are recycled, only one cell is filled with new water, and the quantity of water used is reduced by about two thirds. Some PFPR facilities using a drum rinsing station with 100-gallon water cells have cleaned as many as 70 drums before changing water.

Dry Process Cleaning Equipment

Dry process formulating and packaging lines, which do not generate wastewater, are often cleaned using equipment such as brushes, scrapers, and vacuums. This cleaning equipment will physically remove solids that have adhered to process equipment during the formulating or packaging step. Examples of dry process cleaning equipment include the following:

Floor Scrubbers

Floor scrubbers are mechanical devices that continually recirculate cleaning water to clean flat, smooth surfaces with circulating brushes. They come in a variety of shapes and sizes. During operation, the scrubber collects the cleaning water in a collection tank, which is easily emptied after the cleaning process, or at a later date.

Cleaning floors by other methods, such as a mop and bucket or garden hose, requires larger amounts of water. Floor scrubbers will significantly reduce the amount of water used for floor cleaning while increasing the effectiveness of the cleaning operation. A typical floor scrubber can clean large processing areas in one hour but use only 10 to 20 gallons of water. The use of floor scrubbers also reduces labor costs and water costs.

Flow Reduction Equipment

Flow reduction equipment includes simple mechanical devices that control how water is sprayed during cleaning operations. The use of flow reduction equipment reduces the volume of water generated during cleaning operations, as well as increases efficiency in the cleaning process. Examples of flow reduction equipment are:

Solvent Recovery Equipment

Solvent recovery equipment primarily consists of flash distillation units, which use the difference in boiling points to physically separate organic solvent from wastewaters. Some facilities may generate solvent-contaminated wastewaters during cleaning operations that are unable to be reused in water-based products; other facilities generate water-contaminated solvent wastes that are unable to be reused in solvent-based products. These wastes are fed through the distillation unit at a temperature where the solvent is vaporized from the waste stream. The solvent vapor is then condensed to liquid. These efficient units recover high yields of spent solvent for reuse in later formulations.

The use of solvent recovery equipment can reduce raw material (i.e., solvent) usage and cost. In addition, this equipment can reduce disposal costs by recovering solvent for reuse and reducing the quantity of solvent-aqueous changeover water that is disposed of as waste.

 

Click here for an Adobe Acrobat PDF version of the Chapter 3 in its entirety. [267K PDF file, 8 pages]


CONTENTS

Adobe Acrobat Reader is required to view PDF documents. The most recent version of the Adobe Acrobat Reader Exit EPA Disclaimer is available as a free download. An Adobe Acrobat plug-in for assisted technologies is also available.

316(b) | UNDS | NPDES

Local Navigation

Jump to main content.