Table 5: Main advantage and disadvantages of solid health care waste treatment technologies Technology Advantages Disadvantages Cost (in 2010) Non-incineration technologies Needle cutter - Prevent needle - Easy to operate, low cost - Syringe can be recycled - Needles need further treatment cut and separated - Investment cost: 2-80 USD - Durability: 200,000 cutting Needle destroyer - Needle is disinfected and destroyed by electricity - Easy to operate, low cost - Syringe can be recycled - Require electricity - Stem of needle still exists after destroying. - Investment cost: 100 – 150 USD Innertization - Applicable to chemical waste and pharmaceutical waste - Simple to operate, low cost - Not applicable to other waste - Investment cost of cement, sand Cement bury pit - Applicable to sharps and pathological waste - Simple to operate, low cost - Requires land and space - Potential impact to underground water if poor design, construction - Investment cost: USD/m3 Safe burying - Relatively safe if access to site is restricted and where natural infiltration is limited. - Low investment and operation cost - Only to hospitals in mountainous and rural area - Investment cost: labour, roof, fence Disinfection by steam (autoclave) - Highly efficient disinfection - Reduction in waste volume if shredder available - Low operational cost - Environmentally sound - Well-known technology in hospitals - Inadequate for anatomical, pharmaceutical and chemical waste, and waste that is not readily steam permeable. - Requires trained operator - High investment cost, requires thermal resistant waste bags - Investment cost: 500 – 50,000 USD - Operational cost: 0.33 USD/kg Disinfection by microwave irradiation - Highly efficient disinfection - Reduction in volume if shredder available - Low operational cost - Environmentally sound - Well-known technology in hospitals - Inadequate for anatomical, pharmaceutical and chemical waste, and waste that is not readily steam permeable. - Requires trained operator - Investment cost: 70,000 – 50,000 USD - Operational cost: 0.33 USD/kg 200
- High investment cost, requires thermal resistant waste bags Disinfection by steam & microwave - Highly efficient disinfection - Reduction in waste volume if shredder available - Low operational cost - Environmentally - Well-known technology in hospitals - Inadequate for anatomical, pharmaceutical and chemical waste, and waste that is not readily steam permeable. - Requires trained operator - High investment cost, requires thermal resistant bags - Investment cost: 180,000 – 250,000 USD - Operational cost: 0.33 USD/kg Chemical disinfection - Highly efficient disinfection of pathogen in infectious especially for liquid waste - Reduction in waste volume if shredder available - Some chemical disinfectants are inexpensive - Inadequate for anatomical waste, sharps, chemical and pharmaceutical waste - Requires trained operator - Hazardous chemicals can cause environmental pollution - Operational cost for disinfectants Incineration technologies Single chamber incinerator - Good disinfection efficiency - Drastic reduction of weight and volume of - No need for highly trained operator - Emission of air pollutants - Inefficiency in destroying thermal resistant chemicals and drugs - Investment cost: 1000 – 15000 USD - Operational cost: 0.6 USD/kg or more expensive Two chamber or Pyrolytic incinerator - Adequate for all infectious waste, most chemical waste, and pharmaceutical waste - Drastic reduction of weight and volume of waste - Incomplete destruction of cytotoxics - Relatively high investment - High operational cost - Requires qualified operator - Emissions of air pollutants in case of improper operation and maintenance - Investment cost: 20,000 – 100,000 USD - Operational cost: 0.6 USD/kg or more expensive
Facilities for 2nd level treatment of hospital wastewater include biological treatment facilities for removal of organic substances and a part of nutrients. removes organic substances and a part of nutrients 3rd level treatment removes nutrients and disinfection. Sludge of hospital wastewater treatment plant shall be stabilized, eliminated pathogens prior to off-site transportation. Sludge can be dried in area of hospital wastewater treatment plant. Table 9: Options of technology applicable to hospital wastewater treatment Treatment facility Technological options Septic tank Simple septic tank Baffled septic tank Baffled septic tank with anaerobic filter Waste removal Bar or fine screen for waste removal Mechanically operated screen for waste removal Biological treatment in aerobic or anaerobic condition Attached growth biological treatment Trickling biological filter Submerged biological filter Rotating biological contactor growth biological treatment Mixed aeration tank Aerated-Lagoon reactors Sequencing batch reactor Oxidation ditch nutrient removal Anaerobic - Anoxic - Oxic (AAO) AOAO Other nutrient removal processes Biological treatment in natural condition Constructed wetland Anaerobic or aerobic or facultative Bio-lake Disinfection Chlorine disinfection Ultraviolet disinfection Ozone disinfection Sludge treatment Sludge compressing tank tank Sludge drying facility A hospital wastewater treatment can apply single option or many options of biological treatment, provided that the effluent meet Vietnamese standard TCVN 7382:2004 and the plant is suitable to hospital’s circumstance. 10 Choice of wastewater treatment level by requirements Level of treatment Suspended substances (mg/l) BOD5 (mg/l) Nitrogen and phosphorus 1st level treatment 80 - - 2nd level treatment 25– 80 -