In the modern age of solid waste management, material recovery facilities (MRF) are multiplying like rabbits. However, only limited data exists on the environmental, economic and energy impacts associated with MRF operation. How do the operations affect public health and the environment, as well as occupational health and safety?
In an attempt to answer this question, the Solid Waste Association of North America (SWANA), Silver Spring, Md., conducted a study of six MRFs, including facilities in Islip, N.Y.; Montgomery County, Md.; Albuquerque, N.M.; Hartford, Conn.; Rice County, Minn.; and Orange County, Fla. These facilities are geographically distributed throughout the country, receive both commingled or source separated wastes and employ various techniques to recover recyclables.
The environmental evaluation considered the impacts on ambient air quality, receiving waters and community noise levels. The occupational health and safety evaluation examined chemical exposure, biological aerosols, occupational noise, physical safety and ergonomics. Economic and energy factors also were considered. Testing methods included environmental sampling in the immediate vicinity of each facility as well as indoor and personnel sampling. A certified industrial hygienist also reviewed health and safety programs, conducted personnel interviews and videotaped operations for a subsequent ergonomics evaluation.
The environmental testing measured the ambient concentrations of the following: * Total suspended particulates (TSP);
* Particulates less than 10 microns (PM10);
* Carbon monoxide (CO);
* Volatile organic compounds (VOC);
* Lead; and
* Mercury vapor.
Generally, TSP, PM10 and lead concentrations were well below the applicable state and National Ambient Air Quality Standards (NAAQS). Carbon monoxide and mercury concentrations also were below the NAAQS or the Occupational Safety and Health Agency's (OSHA) Permissible Exposure Limits (PELs). In addition, detectable VOC concentrations were several orders of magnitude below state guidelines, while wastewater quality and community noise levels met federal and state criteria.
The occupational health and safety testing had similar results. For example, the workers' exposure to total dust, respirable dust, silica and metal concentrations were one or more orders of magnitude below the applicable PELs. Carbon monoxide and mercury vapor concentrations also were well below the PELs, while PCB and pesticide levels were below the detection limits of the test method. Airborne bacteria and fungi concentrations measured inside the MRFs were roughly one order of magnitude higher than the levels found outside the facility. Also, the airborne and surface samples of bacteria and fungi inside a facility were relatively consistent from one location to another.
For the most part, worker health and safety programs conformed with OSHA regulations. These programs address issues such as energy control, hazard communication, respiratory protection, hearing conservation and blood-borne pathogens. Ergonomic issues include worker discomfort, fatigue, injury and illness. The most common ergonomic risk factors are improper workstation design and an excessive line speed that doesn't accommodate workers or causes repetitive or awkward motions.
The survey also examined the costs and energy consumption of MRFs relative to their greater integrated municipal solid waste management systems (IMSWMS). All six MRFs represented a net cost to their IMSWMS, depending on the total quantity of MSW and recyclables handled. Similarly, the energy consumption per ton of waste handled typically was higher for recyclables compared with MSW, with collection dominating total energy consumption. Despite these economic or energy disadvantages, most states include recycling as part of their overall solid waste management plans.
Based on the evaluation results, MRFs do not pose a significant threat to public health or the environment. Nuisance conditions, such as fugitive dust and excessive noise, are easily mitigated through roadway maintenance and equipment enclosure.
The study suggested that further research is needed on the effects of worker exposure to pathogenic organisms and ergonomic factors in workstation design. Although no virulent pathogens were detected at the MRFs, it is unclear whether prolonged exposure to the common environmental organisms found at the facilities could cause infection or hypersensitive reactions. The study also suggested that facility design and operations should be evaluated to identify potential ergonomic risk factors and modified to accommodate workers and eliminate unnecessary repetitive or awkward motions.
The survey was conducted with funding from the U.S. Department of Energy's National Renewable Energy Laboratory and the U.S. Environmental Protection Agency's Risk Reduction Engineering Laboratory.
For further information, contact Dianne DeRoze, SWANA, P.O. Box 7219, Silver Spring, Md. 20910. (301) 585-2898.