Disposal refers to the long-term placement of waste or treated waste. It is almost always off-site. We do not classify stotage containers on site as a form of disposal.
Validating sterilization and spore tests
How do you know if the treated waste is safe for disposal? How do you know if it is done?
Sterilization is a process where all living forms of bacteria and organisms are destroyed, removed or inactivated with the help of different processes so that the material can be made completely disinfectant. It reduces the possibility of contamination and thus reduces the chances of disease as well.
Heat treatment processes often use a "time and termperature" criteria. These rest on laboratory validation of the effectiveness of the treatment. Samples of typical waste are subjected to a temperature for a given time (and sometimes with a certain oxygen content in the atmosphere.) If detailed analysis of the samples treated in the laboratory this way shows it is safe for disposal, the operating conditions – residence time and temperature – are written into the operating permit and form a target for the operators of the treatment. If the incinerator or autoclave meet these time and temperature.
When the regulators approve the treatment, they include typically write into the permit requirements for time and temperature. The second and more rigorous treatment validation is the spore test.
The spore test looks for microorganism spores. Some plants produce spores as part of their lifecycle as do algae and fungi. Spores are designed by Nature to be hardy so they are more likely to survive treatment than other living organisms.
State regulatory agencies specify the sterilization validation with spore check. Check with your agency to see what is required.
Sterilization is primarily carried out in all forms of medical and industrial equipment. This is to remove the possibilities of contamination by different kinds of organisms and bacteria and to achieve a better sterile condition. Sterilization processes can be carried out by physical methods as well as Chemical methods. More on sterilization.
Sanitary landfills are a staple of the US waste disposal system. The idea is that the waste will stay in the landfill and not harm the environment until it has degraded to a sufficient level that it is safe. The engineering of these landfills is pretty worked out now. A plastic liner or liners underlies the waste. Waste is deposited in layers and soil from the local area is put on top of the waste. Then another layer of waste goes on top of the soil and another layer of soil on top of that. Different landfill designs have different numbers of layers and the shape discourages waste or leachate from migrating away from the landfill. The plastic liner and configuration of the layers provides “hydrogeological isolation,” so leachate (water that has flowed through the waste) does not enter the aquifer and general groundwater in the area.
Most sanitary landfills also have on-side staff, vertical vents to prevent build-up off off-gas, and monitoring of air emissions.