Principles of Medical Waste Management

Waste Minimization

The overriding principle of all waste management is: don’t create it if you can avoid it. And if you must create the waste, seek ways to keep the quantity small and generation rate low.

Waste minimization is a buzzword, but it’s a buzzword that gives manager and operators a goal. Sometimes simple redesign can reduce waste quantities; other times attention to post-generation handling can reduce needless dilution or mixing of the waste.

Malsparo logoThe US hospital industry has a website called Sustainability Roadmap for Hospitals. It claims "many hospitals routinely throw from 50-70% of their waste into" a regulated waste stream when the actual percentage of waste that needs to be considered regulated waste is closer to 10 percent. If that is true, it points to an opportunity for great savings.

Waste management programs should concentrate on the facility operations, in particular those that generate the most waste. An educational system for employees can try to influence behavior - to keep employees mindful about waste production and segregated correctly so as to reduce the load on downstream treatment processes.

Healthcare managers can also reduce the production of waste through adapting their purchasing and stock control strategies.

Inventory control techniques can help reduce waste. For instance, more frequent ordering of small quantities rather than less frequent, large amounts orders can result in lower levels of inventory, reducing the chances of product expiration. Using the oldest items in the inventory first, making sure to use all content of every container, and monitoring expiration dates can help reduce getting caught with excess product.

While purchasing methodologies differ from organization to organization, if you are looking to reduce waste, you may wish to look to centralize purchasing. An inventory control system can help you use all the contents of every container and reduce losses to product expiration. Keeping track of chemical use throughout the facility can help reduce production of hazardous or infectious waste.

Mixing is easy; separating is hard.

This is one of the general principles of chemical process design, and it applies more widely, even to mixtures of solid particles. It is related to the second law of thermodynamics. You can often theorethically separate materials, but only at the cost of energy. Sometimes that cost can be prohibitive.

Don’t dilute your waste unless you have a very good reason to do so. Dilution increases volume and disposal cost is usually directly proportional to volume or mass.

Don’t mix two different types of waste together – unless you have thought long and hard about it. By putting more than one type of physical or chemical waste in the same batch, you are increasing the specs on the treatment or disposal system.

Keeping different types of waste in the same room or building is often OK. The safety measures for preventing release to the environment installed in a room may work for more than one kind of waste.

Negative air pressure. This can be expensive to set up and incorporate into the building, but it can help reduce the risk of release. Your insurance company and regulatory agencies will be glad if you keep the waste in a room where the air pressure is lower than the pressure in the rest of the building or outdoors. The difference in pressure does not have to be great. Even a few inches of water pressure difference will cause air moving through minor leaks in the building to move from outside to inside. The HVAC system directs the air through filters

Mixtures of different kinds of waste

Any competent regulator is going to look at a stream with more than one classification of waste in it and insist that management (storage and treatment and disposal) be appropriate for all types of waste. So a waste that included RCRA hazardous and pathological waste would have to satisfy regulations for hazardous waste and pathological waste before it is sent to disposal. Harmless healthcare general waste waste (e.g. paper from administrative activities) mixed with biological material can become infectious waste. The resulting increase in mass and volume can make the disposal blow up by an order of magnitude.

Heat Treatment

The ancient Greeks put medical instruments in boiling water to clean them. Even without the germ theory they knew from observation that heat tended to reduce the transmission of disease. Heat is used in treatment of infectious and other medical waste in many ways.

Boiling water is limited in temperature to 212 F or 100 C in an unpressurized container. (In a pressure vessel the boiling point can rise.) While this is hot enough to kill or deactivate most pathogens, to ensure the most hardy bacterial spores are eliminated a higher temperature is required. Autoclaves typically operate at 240 F. Incineration takes place at temperatures above 1000 F (and often 1800 F or more) which is far above the temperature required to kill organisms and denature viruses at more than half a second at that temperature, but the goal of incineration is other than sterilization.

Low-heat thermal processes find their way into many cleaning processes. Steam cleaning of room floors and walls is used to both clean (remove dirt) and disinfect. Microwave treatment is a low temperature thermal process; the bulk temperature is about 100 C.

Microwave treatment is a low temperature thermal process; the bulk temperature is about 100 C and disinfection is due to moist heat.

Proximity Principle

The closer (in both space and time) you address the waste, the better. By address, we mean treat or package for final disposal. This principle is a guide for planning and process design. It can be violated if the overall big picture considerations call for it.

Precautionary Principle

When the risk is uncertain it must be regarded as significant and protective measures must be taken accordingly.

The principle was adopted by attendees at a 1998 conference in Wisconsin about public health and waste. Referred to as “The Wingspread consensus statement”, four central components of the principle were listed:

  1. taking preventive action in the face of uncertainty;
  2. shifting the burden of proof to the proponents of an activity;
  3. exploring a wide range of alternatives to possibly harmful actions; and
  4. increasing public participation in decision-making.

Zero Waste is a Quixotic Goal

You're never going to have a zero waste facility. This is more or less a consquence of the second law of thermodynamics. You can't practically recycle everythihng or stop all waste production. Zero waste is fine as a bright shiny object, but realize you will never get there. The best you can do is to asymptotically approach it.

Assessment of Risk

Large-scale management is often accompanied by formal risk management evaluation for presentation to a regulatory agency or insurance company.

Fault tree analysis can be employed in these situations as it permits operators to estimate individual risks of the storage, treatment, and disposal process elements. Other risk assessment methods include:

Costs vary considerably

Regular non-hazardous municipal solid waste is cheap to store and dispose of. At-risk medical waste (infectious, pathological, hazardous, radioactive, or regulated) is much more expensive. How much more expensive? There is no general answer for that and both relative and absolute costs depend on geography, market supply and demand, and alternatives. A rule of thumb for budget estimates is that these waste cost ten times as much to dispose of as garden variety waste. If you are an ambitious waste management professional, you might want to try to calculate how much each each of your waste streams costs to store and dispose of on a per pound basis.

Myths about Medical Waste

Waste Assessments

Dimensions of Medical Waste