Waste characterization & analysis: now, it pays to know your wastes.

Waste Characterization & Analysis: Now, It Pays to Know Your Wastes

Understanding the characteristics of waste is fundamental to selecting, designing and implementing waste management solutions in the foundry industry. The enactment of land disposal restrictions for the "third-third" scheduled wastes last May and the recent promulgation of Toxicity Characterization Leaching Procedure (TCLP), make it essential for foundries to have their wastes characterized.

Even foundries that have done so need to update their studies. Obviously, foundries are not static operations. Since processes, raw materials and waste products invariably change, it is imperative that plant personnel know when and how their wastes may be changing and how these changes affect the regulatory status of the wastes. Wastes below hazardous limits could creep above the regulatory levels.

Each waste should be tested a minimum of once a year, though no federal statute mandates this. Wastes shown to vary should be retested more frequently.

Characterization

Advantages

The benefits of knowing all about plant waste materials and processes make possible intelligent decisions regarding waste management options such as:

* whether wastes are being disposed or handled according to regulations;

* the minimization or reuse of certain waste materials;

* whether disposal or constructive use options can reduce costs and liability.

Determining waste disposal options by knowing waste characteristics is important in reducing costs because many states have waste categories with different disposal requirements.

In some cases, a foundry may be combining several wastes before disposal in a hazardous waste landfill. However, it may be that only one or two production processes generate hazardous waste. Segregating these waste materials often can reduce the amount and cost of hazardous waste disposed.

Waste characterization is also important to foundry compliance with:

* land ban/TCLP regulations;

* SARA Title III reporting;

* Employees' Right-to-Know;

* Superfund joint and several liability.

TCLP

The new TLCP regulations (published March 29, 1990, Federal Register, vol 55, no. 61, pp 11797-11877) that replace EP-Toxicity require evaluation of 39 constituents, including volatiles and semi-volatiles. They add 25 chemicals to the previous 14 tested under EP-Toxicity. Organic chemicals that must be evaluated now include methyl ethyl ketone, benzene, tetrachloroethylene and vinyl chloride.

Foundries that generate 1000 kg/month or more of hazardous wastes must have complied with the TCLP regulations by Sep 29, 1990. Foundries that generate between 100-1000 kg/month must be in compliance by March 29, 1991. (EP-Toxicity tests can be used to evaluate wastes before the 1991 deadline.)

Many foundry managers were concerned that toluene and some phenols would be included in the new regulations. While EPA has not promulgated standards for these chemicals, it may add standards for them later.

There is a great advantage for foundries to test their wastes and, if they are determined to be hazardous, develop solutions before treatment standards are mandated. Those that have not done so may find it economically advantageous to have a thorough waste characterization and analyses (WC&A) performed at the same time TCLP tests are conducted.

Land ban and TCLP regulations put the burden on waste generators to determine whether their waste is hazardous and to bring their operations into compliance. Documenting wastes' characteristics is critical when state or federal agencies question treatment, handling or disposal techniques.

Conducting the Study

A waste characterization study is a systematic process involving several steps:

* setting objectives;

* reviewing the raw materials;

* determining material/process flow;

* waste identification and quantification;

* sampling, laboratory analyses and interpretation.

Before conducting a study of the characteristics of foundry waste materials, it is important to determine the objectives of the study. Identifying objectives allows the waste characterization team to ensure that test procedures will yield information needed to meet these goals.

Typical objectives include:

* classification of all process wastes as hazardous or nonhazardous or some other designation defined by state regulations;

* estimates of waste quantities generated at current and projected production rates (espcially important for SARA Title III reporting);

* evaluation of current waste management practices;

* identification of opportunities for waste minimization or recycling.

Waste Identification

Though foundry operators know their operations and can perform limited waste sampling, it may be necessary to hire an engineering firm to conduct the actual waste characterization study.

A typical foundry can generate from eight to 40 individual wastes. Identification of each generation point is important to avoid overlooking wastes generated infrequently or in small quantities. Small-quantity wastes may not have a major impact on disposal costs or handling procedures, but they can have significant regulatory implications.

Wastes that have the potential to vary significantly from day to day may need to be sampled over a longer period of time to obtain accurate characteristics and quantities readings.

Sampling

A carefully structured sampling program ensures that representative waste samples are collected sufficiently to meet federal and state requirements. Some states set specific criteria for the number and frequency of samples collected. Each waste must meet proper sampling protocols including health, safety and decontamination procedures, sample preservation, transportation procedures and chain-of-custody forms.

Laboratory Analyses

The types of laboratory analyses to which waste samples are subjected are dependent upon the overall objectives of the study, but they should be a composite of the norms required by regulatory agencies.

Whether wastes are to be classified as hazardous or nonhazardous is subject to tests under RCRA (Resource Conservation and Recovery Act) for ignitability, corrosivity and the "toxicity characteristic." Typically, EP-Toxicity, and now TCLP, tests are the most relevant for the types of waste generated by foundries. Both tests are intended to assess the leaching potential of an industrial waste in an environment where acidic leaching conditions are present, as in a municipal landfill.

However, in many cases, industrial waste is disposed in a segregated area of a landfill or in a monofill where water leaching tests may provide a more accurate picture of leaching conditions.

Results of these various analyses can be compared to determine what percentage of the particular constituents present in the wastes is released under different leaching conditions.

Interpreting Results

Results of a waste characterization study should:

* identify hazardous wastes;

* estimate future waste treatment/disposal needs;

* identify waste minimization opportunities, reduce/alter product requirements, change raw materials, improve process controls, recycle materials to the original manufacturing process, recycle or beneficially reuse materials to other processes and treatments;

* identify needed waste management changes (segregation, storage, disposal and transporation of wastes);

* determine constructive uses for some wastes rather than disposal;

* better delineate process changes that could affect waste materials and disposal procedures.

Environmental regulations are impelling foundries to consider innovative alternatives for managing their wastes. The first step in any waste management program is to understand waste characteristics and evaluate options based on those characteristics.