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Volume 9, Number 1           A Gossman Consulting, Inc. Publication       February 2004

Acceptance and Rejection of Hazardous Waste Fuel at Cement Plants


David Gossman, Gossman Consulting, Inc.


The acceptance or rejection of individual shipments or drums of hazardous waste at hazardous waste fuel blending or burning facilities must focus on five key factors needed to ensure the success of a project.  This review of the parameters associated with each of these five areas will demonstrate the importance of thorough laboratory analysis of each shipment of waste received at the facility.  Based on the relative consistency and sources of other alternative fuels and raw materials (AFR) many of these same factors may be applied to other AFR programs as well.

Fuel Quality

The first and perhaps most obvious criteria in the acceptance or rejection of a shipment is whether or not the waste is a fuel.  Generally this requires a heat content analysis.  Many facilities have added the criterion of total water content to this portion of the evaluation as well.

Process and Product Protection

Product and process protection requires analysis and control over a wide variety of parameters. These include halogens, sulfur, selected metals, radioactivity and ash as examples that protect the kiln system and clinker product. There is also the need to protect the storage and feed system. Incompatible wastes that can gel or react must be avoided, pH must be controlled to prevent corrosion and viscosity may need to be controlled to maintain pumpability of liquid wastes. All of these parameters can be tested using high-speed methods of analysis. By implementing a system of data quality objectives (DQOs) it is possible to avoid analytical burdens that go beyond what is actually needed.

Protection of Human Health and Safety

Protection of human health and safety is one of the most important functions performed by the analysis of the waste streams.  Unfortunately, it is often the most overlooked both by operators and regulatory authorities. Employees involved in operating the hazardous waste fuel blending, storage and feeding systems as well as laboratory workers and samplers are the most "exposed" and any program for controlling receipt of wastes must take into account the worst case as well as normal exposure levels of these individuals to the waste. It is for this reason that it is critical that there be an organic analysis of every waste stream prior to shipment to the plant and a second organic analysis upon receipt to confirm that there are no compounds or combinations of compounds that could result in either acute or chronic toxic exposure. Examples of wastes that have been received and potentially endangered employees at hazardous waste facilities are numerous. A few are listed below:

Propylene glycol dinitrate - This is a component in "Otto Fuel II" which is torpedo fuel. In the mid 80s an incinerator in North Carolina receiving this waste allegedly caused the chronic poisoning of a number of employees. At low levels this compound is a chronic nerve toxin. It has an ACGIH skin exposure based TWA TLV of .05 ppm.

Toluene diisocyanate (TDI) - TDI is a common industrial chemical used in numerous chemical manufacturing processes including the production of polyurethane foams. It has an ACGIH TWA TLV of .005 ppm. A few years ago it in combination with other TDI production wastes and chlorobenzene was involved in the explosion of a rail car at a cement plant where it was being used as waste fuel. This material is highly water reactive and can react with itself when heated producing gas, heat and pressure. The resulting explosion caused considerable damage at the plant.

Amines - As a general class there are many amines with ACGIH TWA TLVs of close to 1ppm. Further, amines can be involved in hazardous polymerization reactions with some compounds found in liquid hazardous waste fuels such as vinyl acetate. In one case amines were added to a tanker of hazardous waste fuel to adjust the pH of the material. It was then shipped to the cement plant. Upon arrival at the cement plant the increase in temperature that had occurred inside the insulated tanker created fumes that almost overwhelmed the truck sampler when he opened the truck hatch even though he was wearing a full-face organic cartridge respirator. The hot tanker required implementation of the facility's emergency response plan.

There are numerous other examples. Only through thorough analysis of the waste and expert review of the resulting data can these types of incidents be avoided.  Our next issue will discuss options for setting up a system to fully utilize the results of organic analyses to protect employee health and safety.

Environmental Protection

Generally speaking if the process and product are protected and the individuals handling the waste are protected there are only a few additional concerns that need to be addressed relative to protecting the environment. One of these is mercury (Hg). Other semivolatile heavy metals such as cadmium (Cd) and lead (Pb) may also need controls beyond that required to protect product quality in order to protect the environment. As with all the analytical requirements discussed, careful development of DQOs can significantly reduce the analytical burden and make the testing of every shipment of waste received a cost effective option for reducing costs attributable to actual and potential liability.

Compliance with Permits and Regulations

One might be tempted to believe that these criteria would have already been covered by protecting people and the environment. Sadly this is not the case. Quite often the regulatory authorities implement requirements that are unrelated to protecting human health and safety or the environment. A good example is the common restrictions on PCBs and dioxins in waste fuel used in cement kilns. While these compounds are completely destroyed in cement kilns it is nevertheless common to see their receipt restricted at waste fuel facilities due to public misconceptions regarding toxicity of (nonexistent) emissions.  It is therefore virtually always a requirement that an analysis for PCBs be performed on a waste fuel sample prior acceptance as fuel. The method for rapidly doing this using gas chromatography was developed by this author over 20 years ago and current technology allows this to be done within 20 minutes of receipt of the sample in the lab.