Chapter 2

Chapter 2 – Recognizing Pollution Prevention Opportunities

Organizing Pollution Prevention Options

Pollution can be prevented in many different ways. All methods can be organized into five categories:

  • Chemical substitution
  • Material flow
  • Process control
  • Automation
  • Technology

These categories will likely overlap with each other as they are examined and implemented. Using these categories will help during the options analysis step in the pollution prevention planning process.

Chemical Substitution

Chemicals may be substituted that are less hazardous and polluting. This can be done in three different ways. First, simple product substitution can directly impact the level or hazard of the pollutant. For example, many facilities replaced chlorinated solvent cleaning systems with aqueous-based cleaning systems when the Montreal Protocol phased out the manufacture of chlorinated fluorocarbons and some other chlorinated solvents due to their ozone-depletion potential.

Second, less hazardous carrier or solvent chemicals can be used. Virtually all coating operations use a carrier to dissolve and transport, by brushing or spraying, the desired coating. Water based or powder paints may be used instead of solvent-based paints that contain volatile organic compounds (VOCs) such as toluene.

The third situation involves chemicals that are changed during the process into a more hazardous polluting material. In this case, there may be a substitute that will not be transformed in such a way. An example is a curing process where initially non-toxic chemicals are changed to more hazardous chemicals when reacting or polymerizing under ultraviolet light. These situations can be difficult to find substitutes for because of the many interactions that are going on in the process and the desired results.

Whenever chemicals are substituted it will affect other parameters of the process. Equipment may have to be modified; the process itself may need to change; training on how to handle the new chemical may be needed. A direct substitution often requires other process changes.

Material Flow

Tracking and controlling how a chemical flows through processes in a facility is an important way to prevent pollution. Material flow includes activities like water conservation practices, inventory control, efficient use of chemicals, and storage.

In many cases, how water is used and routed through a facility is intertwined with pollution and waste issues. Water is prevalent in rinsing, cleaning, movement, and other common industrial operations. As a result, many pollutants end up in wastewater, requiring it to be treated before being discharged from a facility. By tracing where water enters a facility, where it flows internally, how it is sent to the various areas for use, and how it is used may reveal ways that pollutants are introduced. Since water is a resource that must be paid for at both purchase and disposal points, a water flow analysis may reveal areas where water can be conserved.

Like water, chemicals should also be tracked through the system to identify areas where use or generation can be reduced. In chemical process solutions, optimize the concentrations of chemicals to the minimum required to obtain the desired results. Work with vendors to minimize storing chemicals on site by implementing “just in time” (JIT) delivery practices. Inspect chemical transport systems and storage areas for leaks and other losses. Develop an effective tracking system of chemicals shipped, stored, transported, used and treated or emitted. Other commonly monitored factors include expiration dates, rotation of stock and worker safety.

Even small quantities of chemicals, whether used or unused, are expensive to dispose. Companies should have a restrictive policy on accepting samples to avoid the accumulation of small quantities of obscure or rarely used materials. Preferably, no samples should be allowed. In lieu of this, vendors should be required to accept returns of any unused samples. Vendors may also suggest installing an entire process line to test the product capabilities. Companies should have a clear agreement with vendors who will be responsible for removing any unused or generated chemicals during the trial period. Even if a vendor agrees to pay for removal, the host company is seen as the generator and must comply with all relevant regulations.

In general, any and all systems that transport, store, dispense, and otherwise move water and other chemicals through a facility are necessary for the company to function. These systems must be given the attention that is required in order to prevent pollution and losses that make the company less profitable. Focus on the source of the waste as much as on the waste itself.

Process Control

Process control is about people and ensuring that jobs are done properly so that waste and pollution are minimized. It involves examining the work environment to see if it allows employees to do the job effectively. Written procedures and documentation of completed tasks, training, and auditing are key elements in process control to prove that jobs are being done correctly.

First, determine if the materials that document the process are accurate, complete, and understandable. This includes process control sheets, raw material and use logs, training materials, engineering schematics, and step-by-step production procedures. From these documents it should be clear what materials to use and how to identify, measure, and move them. The documents should contain all the other relevant information that describes what must be done. They should also include information on what to do if something unexpected happens. If the process in question is missing any part of the documentation, then it should be developed.

Questions to ask when evaluating training documentation:

  • How are workers trained in the process?
  • Is training clear and convenient?
  • Is it regularly updated and completion documented?
  • Is process-related procedure documentation easily available at the work site?
  • Are preventative maintenance procedures being followed?
  • How do workers provide feedback and suggestions to supervisors or engineers?

Once it is clear that all the documentation is available, evaluate the method that is used to communicate this information to the workers. Workers must have a clear understanding of the job process and the consequences, both to themselves and the company, of not following their training.

Auditing should be done to verify that the production processes are being performed properly. If a job is not being done as prescribed, the reason should be determined. Documentation may be faulty, the equipment may be malfunctioning or training may be insufficient. In any case, deviations from the expected audit results should be analyzed and corrective action implemented to improve the system.

Results from auditing can be used to plan further enhancements to the production process. Again, focus on the source of any waste or pollution.


Automation can be used to eliminate human error or inaccuracies in process performance, especially for repetitive procedures. It may decrease workers’ exposure to hazardous chemicals.

Automated processes can be controlled or programmed to easily test and improve a process to minimize waste. For example, water conservation techniques can be greatly automated. Inexpensive equipment such as flow restrictors, timers and solenoid valves can be used to activate and control processes that use water. Painting operations can be precisely controlled with automated spray guns and conveyor systems. Many sequential chemical dipping operations, such as plating, have been automated to minimize chemical wastes and conserve water.


The most creative and radical way to prevent pollution is to change the technology that is used to make a product. This will involve all four of the other ways to prevent pollution. It may mean a totally new mindset in how to do something. It may mean using no chemicals at all, instead using mechanical methods to accomplish what chemicals had done. Due to the changes in employee roles and responsibilities that accompany a technology change, it may be the most difficult but is often the most effective way to prevent pollution.

Technology changes can also prevent pollution through the design stage. The concepts of Design for the Environment (DfE) can be used either to design a new product or redesign an existing product. DfE allows design teams to take a new, creative and resource-efficient look at specifications and features. The concepts of DfE consider the environmental impacts of the design of a product not only in manufacturing but in its entire life cycle. The benefits of DfE include improved market position, reduced manufacturing and user costs, and reduced regulations and liability resulting from a product designed to minimize waste from the beginning.