1. Way of working: Incineration
By incineration, hospital waste and the pathogen agents are oxidized. State of the art incinerators are two chamber systems equipped with a two stage flue gas treatment and a CEM-System.
While in the first chamber the waste is pyrolsed at a temperature of 300 – 500°C, in the second chamber the pyrolysis gas is treated at a temperature of 800 – 1200°C.
Parameters to be obtained:
Temperature, Time, Turbulency
Healthcare waste incinerator, Hoval, Lichtenstein

2. The economical problem of incineration
€/Kg
Treatment by hazardous waste incineration (Oxidation)
100 %
25 %
Treatment by autoclaving (Disinfection)
Disposal costs for household like waste
2002
2003
2004
2005
2006
time
Due to the to be expected increase of emission standards and strong environmental laws, the cost for the incineration of hazardous waste waste will exponentially rise up in the future.

3. Overview: Incineration
Advantages
Non-recognizable residues
Reduction of the volume to 90%
Safe elimination of the
biological agents
Disadvantages
High investion costs for the incinerator flue gas treatment system and the CEMS
High environmental impact
High maintenance and operation costs
Inflexible capacity
Long waiting times before repair and maintenace is possible
Highly trained personal is needed
Problematic disposal of fly ash and ash

4. Way of working: Chemical disinfection
During the chemical disinfection process, disinfectants (e.g. dissolved chlorine dioxide, sodium hypochlorite, peracetic acid, etc.) are used to disinfect the waste.
To ensure contact between the chemicals and the pathogens, waste normally has to be shredded prior to disinfection.
To ensure a good disinfection result, parameters like pH, temperature, presence of other chemicals, etc. must be obtained and the system must be able to replenish the chemical disinfection lost.
Notice: According to the UN technical guidelines on hospital waste management, chemical treatment methods are not recommended due to the combined environmental and work safety problems!
Chemical disinfection unit: Sterimed System, MCM Israel

5. Overview: Chemical disinfection systems
Advantages
Reduction of the volume up to 80% (depending on the used shredder system)
Non-recognizable residues
Disadvantages
High operation costs due to the use of chemicals
Low and unsure disinfection level
Difficult repairs at the shredder, blocking of the shredder
Risk of occupational exposure to the workers
Low maximum capacity
May result in disposal problems of the treated waste
May result in waste water problems (long-term environmental consequences)

6. Steam treatment system
Today, different alternative thermal healthcare waste treatment systems are available. The systems can be categorized in:
Systems without removing the air (Non-vacuum Systems)
Microwave, Heated screw systems, Hydroclave, etc.
Pre-vacuum systems
“Classical”, old autoclave cycle
Fractionated cycle (several pulse system)
New and advanced Autoclave cycle for sterilization instead of disinfection
Others (e.g. Ecodas System)

7. Alternative hospital waste treatment by steam
The way of alternative waste treatment by an steam treatment unit is based on a thermal disinfection or sterilisation process, well known from the sterilisation of hospital equipment.
The treatment happens at high pressure (e.g. 3,2 bar) and temperature (e.g. 134°C) in a nearly 100 % saturated steam atmosphere cause:
In a wet atmosphere, germs are more heat sensible
Saturated steam under heat and pressure acts as a soft acid and destroys organic substances like germs
Enthalpy energy will be set free during condensation directly on the inner- and outside surfaces of the waste – the place of the germs

8. EUROPEAN COMMUNITY (DG XI)
Results of the
EC Priority Waste Stream Project:
„Waste from healthcare“
„A trend away from independent waste disposal systems operated by individual hospitals, towards centralised disposal systems“
„A trend towards pre-treating technologies (steam sterilization) alternative to incineration“

9. BASEL CONVENTION
Steam sterilisation by autoclaving is listed as the
PREFERRED METHOD
for the treatment of healthcare waste
„ … Methods other than steam sterilisation should be selected only, if this is impracticable or inappropriate”
The worldwide trend seems definitely be moving towards autoclaving as a preferred alternative to the problematic incineration.