Following is a contribution by AIC Company General Director Dr. Nguyen Thi Thanh Nhan. – Ed.
Currently, Vietnam has nearly 13,700 medical facilities, including 1,260 hospitals; 1,037 prevention medical facilities; 100 training institutions; 180 pharmaceutical production facilities and more than 11,100 medical centers at the ward and commune level. The total amount of medical wastewater from hospitals and medical facilities is around 125.000-150.000 m3/day and night.
Medical wastewater of hospitals and medical facilities is defined as liquid with solvents born in the hospital. In the hospital, wastewater contains chemicals and various microorganisms, especially pathogenic microorganisms causing disease and other sources. The chemicals are present in hospital wastewater from many groups, such as antibiotics, disinfectants, pharmaceuticals), radioactive isotopes, etc.
Hospitals and medical facilities’ discharge of untreated medical wastewater into the natural environment, medical wastewater collection network of the city, can cause many problems such as a public health threat, causing imbalances in ecology of the water body, toxins accumulated in the ecological chain and environment.
The medical wastewater treatment in hospitals and medical facilities is paid much attention to by the party and state, is regarded as one of the national key programs during the development and integration of the country.
Medical wastewater is generated in the hospitals from three main sources:
- Medical wastewater from treatment, laboratory rooms (surgery, hematology, blood transfusion, contagious disease containing a variety of specimens with microbial pathogens, viruses, parasites, etc.)
- Medical wastewater from pharmacy, there are drugs, vaccines, sera, organic solvents, testing chemicals, radiation chemical from the imaging divisions, etc.
- Living wastewater from outpatients, inpatients, patients‘ relatives, officers and employees, from the cafeteria, etc.
It is able to see that:
- Medical wastewater of hospitals and medical facilities is at the ratio of biological oxygen demand (BOD)/ chemical oxygen demand (COD) > 0.4-0.5, so it is suitable for processing by microorganisms. The ratio of BOD/COD of several hospitals is less than 0.5 (central hospitals, general hospitals) due to the presence of persistent hydrocarbon components by microbiology (laboratory chemicals, preservatives, detergents, etc.) in medical wastewater
- Medical wastewater of hospitals in Vietnam is at the ratio of low BOD/N-T (central hospitals 1.83, provincial hospitals 1.93, sector hospitals 2.9, general hospital 1.96, TB hospitals 3.1, maternity hospitals 2.57) as compared with living wastewater (BOD/N-T = 3.5-5)
- Compared with standard organic medical wastewater to design the processing equipment from Japan, Germany and Taiwan (BOD/N-T = 5), the hospital wastewater in Vietnam is “missing” BOD, COD and “excessing” Nitrogen
- The cause of lacking BOD, COD in wastewater in Vietnam’s hospitals is due to the anaerobic decomposition process of hydrocarbons into CH4 in septic tanks in the hospitals. (In Japan, Germany, etc. there is not this treatment process)
- The technologies of Vietnam (until 2007) are backward compared to the world. Specifically, according to the diagram of developing medical wastewater treatment technologies in hospitals and medical facilities by activated sludge, the technologies in Vietnam just stand at processing hydrocarbons, i.e. BOD, COD, with less attention to the denitrification problem, including ammonium nitrogen and total nitrogen, i.e. corresponding to the technologies in years of 1960-1970 of the world
- Lacking the processing of reducing Nitrate and total nitrogen (i.e. the process of anoxic)
- No clear role in the anaerobic process in reducing other polluted components such as phosphorus, heavy metals, substances and chemical sterilization of medical waste from specialized hospitals and medical facilities
- Never giving a scientific basis to combine the process of anaerobic, anoxic and oxic process in medical wastewater treatment in the particular cases. Not paying much attention to the characteristics of the discharge and in accordance with the conditions of the infrastructure of hospitals and medical facilities
- Unsustainable and unsynchronous status of devices, much dependent on awareness and knowledge of the operator.
- Comments are consistent with survey results from 250 objective hospitals and medical facilities highlighted that the efficiency is not high (35-70 percent only capable of handling microorganisms and pathogens) and approximately 65-70 percent handling chemical and physical parameters
Basis for choosing technologies for medical wastewater treatment includes:
- Ability to perform medical wastewater treatment meeting the requirements of NTR 28: 2010 by MONRE – Column A
- Meeting the flow and discharge mode, the nature of the input wastewater, in accordance with operating conditions of hospitals and medical facilities
- In accordance with the conditions of land, location and infrastructure of works of the hospital, there is flexibility in installation and operation, not causing secondary pollution (odor, noise, worsening landscape of hospitals)
- There is reasonable investment policies and operating costs
- Ensuring stable and sustainable operation, less dependent on human factors
- Technology in line with the level of development of the world and regions
The microbial technology selected to handle medical wastewater for hospitals and medical facilities in Vietnam meets the economic criteria and techniques mentioned above to integrate the anaerobic, anoxic and oxic processes -- referred to as the AAO. This technology should be implemented in the flexible modular device with appropriate capacity, carefully calculated to hospitals and medical facilities
The approach to deal with AAO applied in our country demonstrates superiority versus other technologies capable of handling contaminated medical wastewater in hospitals, meeting satisfactory output in NTR 28: 2009/BTNMT
Through practical activities in Vietnam from 2008-today the treatment plants have confirmed the effectiveness of the technical, environmental and social as well as economic efficiency (investment rate, operating costs calculated for 1 m3 of medical wastewater as moderate), occupying less space, not causing secondary pollution, especially with durability, reliability, and stability. AAO technology with flexible modular devices have been medical wastewater treatment for more than 1,000 hospitals and medical facilities nationwide.
The cooperation with partners from advanced countries to applications in recent years in order to learn and draw experiences in the integration period, the study to complete technical solutions suitable for Vietnamese conditions, as well as the gradual organization of equipment manufactured in the country will create favorable conditions for AAO technology with flexible modules to be more widely used in medical wastewater treatment, industrial wastewater, wastewater from urban and villages, etc. and contribute to the cause of protecting the environment, enhancing quality of life for the people.