|Year : 2013 | Volume
| Issue : 2 | Page : 99-106
Liquid biomedical waste management: An emerging concern for physicians
Department of Pharmacology, SCB Medical College and Hospital, Cuttack, Odisha, India
|Date of Web Publication||16-Sep-2013|
Sasmita Biswal, Department of Pharmacology, V.S.S Medical College, Burla, Odisa - 768017
Source of Support: None, Conflict of Interest: None
The safe and effective management of health care biomedical waste has received much attention for improper and inadequate management is associated with an increase in the incidence of health risks to the healthcare workers, the patients, and their environment and to the community at large. Hence the development of safe and effective management of biomedical waste along with handling protocols, institutional plans and policies, appropriate training and feedback programs on proper waste management and handling for all the healthcare workers are highly recommended. In India, with the implementation of Biomedical Wastes (Management & Handling) Rules 1998, emphasis is being placed mainly on the proper handling, segregation and disposal of the healthcare waste by which the risks and hazards to an individual and to the community can be considerably reduced. Though a technology and treatment protocol already exists, liquid biomedical waste management still remains a major problem for all healthcare facilities. So proper training in handling of waste will enable the healthcare facility to diffuse this critical problem safely and cost effectively while managing their liquid biomedical waste. So a literature search using the terms liquid biomedical waste was done and this review describes the problems associated with its management.
Keywords: Biomedical waste, disinfectants, effluent treatment plant, liquid waste, management and handling rules, sludge
|How to cite this article:|
Biswal S. Liquid biomedical waste management: An emerging concern for physicians. Muller J Med Sci Res 2013;4:99-106
| Introduction|| |
Hospitals and other healthcare facilities are responsible for the delivery of patient care services and during this process certain amount of waste is generated in the form of swabs, discarded syringes and plastics, unused specimens etc., which are collectively known as biomedical waste. So the term ''Bio-medical waste'' means any solid or liquid waste including its container and any intermediate product, which is generated during the diagnosis, treatment or immunization of human beings or animals or in research pertaining thereto or in the production or testing thereof. As a part of the patient care services, these also need to be disposed off safely and effectively. The physicochemical and biological nature of these components, their toxicity and potential hazard are different, thus necessitating different methods or options for their treatment and final disposal. According to the WHO, incorrect and improper management of healthcare bio waste can have direct impacts on the community, individuals working in health care facilities, and the natural environment.  Hence, it is the ethical responsibility of the management of hospitals and health care establishments to have concern for public health and the community.
Wastes generated in healthcare settings include sharps, pathological wastes, infectious wastes, radioactive wastes, mercury containing instruments, and polyvinyl chloride plastics. The WHO has stated that 85% of such hospital wastes are actually nonhazardous, around 10% are infectious, and around 5% are non infectious but hazardous. 
Prior to 1998, the management of healthcare waste in India was the responsibility of municipal or governmental authorities. In 1998, the Government of India implemented the Biomedical Waste Management and Handling Rules, 1998 which specifies that the hospital waste management is a part of hospital hygiene and maintenance activities, such as collection, transportation, treatment, operation of processing systems, and appropriate disposal of waste is a liability for the hospital management. 
The implementation of the Biomedical Waste Management and Handling Rules 1998 also made it mandatory for hospitals, clinics, other medical institutions, and veterinary institutions to dispose of biomedical solid waste according to the Law. The waste originating from different kinds of such establishments has been categorized into ten different types [Table 1], based on the risk of causing injury and/or infections during handling and disposal and the treatment and disposal options required. 
| Liquid Biomedical Waste|| |
Amongst all the category of BMW, liquid wastes pose a serious threat to human health and the environment because of their ability to enter watersheds, pollute ground water, and drinking water when improperly handled and disposed. At the same time, illegal and unethical reuse of this untreated waste, can be extremely dangerous and even fatal in causing diseases like cholera, plague, tuberculosis, hepatitis B, diphtheria etc., in either epidemic or even in endemic form, which can pose grave public health risks and consequences and thus is a major problem for healthcare facilities, their employees, and the community at a large. 
Wastewater is not similar to sewage, for the former is any water that has been adversely affected in quality by anthropogenic influence and comprises liquid waste either discharged from health care facilities (HCF) or from domestic residences, commercial properties, industry, and or agriculture and encompasses a wide range of potential contaminants and microbial concentrations whereas sewage is a subset of wastewater that is contaminated with feces or urine.
Since management of liquid waste is both confusing and conflicting this article reviews, their characteristics, handling options, emergency response and guidelines to be followed during a spill response, the legal aspects involved therein and some novel options that can be opted for their management and handling. A literature search using the terms liquid biomedical waste was performed with Pubmed, Google Scholar, and selected Ovid bibliography searches (up to October 2012).
| Types of Liquid Waste|| |
The liquid waste generated from a HCF is usually of the following types:
- Infectious waste
- Blood and body fluids
- Laboratory wastes (cultures of infectious agents, cultures from laboratories, biological, discarded vaccines, culture dishes and devices)
- Chemically hazardous
- Formaldehyde (obtained from pathology labs, autopsy, dialysis, embalming)
- Mercury (broken thermometers, sphygmomanometer, dental amalgams)
- Solvents (pathology and embalming)
- Radioactive isotopes
- Pharmaceutical liquid waste (discarded/unused/expiry date medicines)
- Photographic chemicals (fixer and developer)
- From cleaning and washing water channeled into the drain.
| Hazards and Challenges of Liquid Bio-medical Waste|| |
Most existing systems and technologies being used in handling liquid biomedical waste are failing to address the problem of effective management of liquid waste. For instance, the routine exercise of pouring biomedical liquid waste is being questioned for posing higher infection threat to medical staff due to its susceptibility to spilling, splashing, and aerosolizing. Untreated liquid biomedical waste contains a wide variety of contaminants that poses health hazards to the community. The wastewater treatment plants can be an additional source of release of methane gas into the atmosphere, which requires capture, destruction, or utilization to reduce the possibility for reducing greenhouse gas emissions.
Around 90% of the wastewater produced globally from the HCF remains untreated, causing widespread water pollution, especially in low income countries. Besides there is increase in the use of this untreated wastewater for irrigation due to the scarce water resources.
| Segregation and Management of Liquid Waste|| |
According to the Biomedical Waste Management and Handling Rules 1998, liquid pathological and chemical waste should be appropriately treated before being discharged into the public sewer systems. Pathological waste must be treated with chemical disinfectants, neutralized and then can be flushed into the sewage system while the chemical waste need to be first neutralized with appropriate reagents before being flushed into the sewer. Thus, liquid waste management includes procedures and practices that prevent discharge of untreated pollutants to the drainage system or to water bodies as a result of the creation, collection, and disposal of non-hazardous liquid wastes.
Hence, these wastes should be first segregated and contained in leak proof, rigid containers and then has to be disinfected or neutralized, with an approved chemical decontamination agent at the site of generation.  These containers are labeled with the biohazard symbol and the word "Biohazard" is to be clearly mentioned in the label. If transport is required before decontamination, then it should be collected ideally in a twin bin container and transported through public hallways is to be kept to a minimum. The twin bin container consists of, a primary container containing the liquid waste which is placed within another secondary leak proof, rigid container (e.g., pail, box, or bin), so as to avoid an impending spill response, during transport. The secondary container must be labeled with the biohazard symbol and the words "biohazardous waste" or with words that clearly denote the presence of infectious or biomedical waste. The outer container can either be protected from contamination by a disposable liner, which is replaced when the biohazardous waste is removed, or the outer container can be decontaminated following each use.
| Disposal Procedures for Infectious Liquid Waste|| |
Sanitary Sewer Disposal Methods
The sanitary sewer system is designed for the disposal of certain liquid wastes. Use of the sanitary sewer reduces the chance for leaks or spills during transport and thereby reduces disposal costs.  Chemical disinfection is done prior to sewer disposal with the aim to eliminate micro-organisms or to reduce the microbial load. Chemical treatment usually involves the use of 1% sodium hypochlorite solution with a minimum contact period of 30 min or other standard disinfectants like, 10-14 gm of bleaching powder in 1 l water, 70% ethanol, 4% formaldehyde, 70% isopropyl alcohol, 2 5% povidone iodine, or 6% hydrogen peroxide.
Disinfection of culture media differs a little from the usual disinfection process, where due to the high microbial load and the rich protein content of the media plates, rigorous disinfection is required, where inactivation should be done by 5.23% sodium hypochlorite, in a 1:10 dilution and should be left for a minimum of 8 h covered and then finally disposed down the sanitary sewer, followed by flushing with a lot of cold water for a minimum period of 10 min.
Sodium hypochlorite solution, also known as bleach, is a broad-spectrum disinfectant that is effective for enveloped viruses (HIV, HBV, HSV), vegetative bacteria (Pseudomonas, Staphylococcus, and Salmonella More Details), fungi (e.g., Candida), mycobacterium (M. tuberculosis and M. bovis), and non-enveloped viruses (Adenovirus and Parvovirus), should be stored between 50 and 70°F. Undiluted household bleach has a shelf life of 6 months to 1 year from the date of manufacture, after which it undergoes degradation at a rate of 20% per year until a total degradation to salt and water. Though a 1:10 concentration of bleach solution has a shelf life of 24 h only, some manufacturer prepared 1:10 bleach solutions, contain a stabilizer that increases the shelf life to approximately 18 months.
Recommended Guidelines for Pouring Biomedical Liquid Waste Down the Sanitary Sewer
While the practice of pouring liquid waste down the drains, itself in not inherently illegal, because the wastewater treatment plants can effectively handle liquid medical waste as they would residential waste, but the way hospitals actually do it is important, for it can get them into serious trouble if they are not careful or smart. That is because of the healthcare worker's dangerous exposure to splashing and aerosolized particulate matter from the infectious fluid. Though this option is very economical for the hospital with the healthcare worker sporting all the required personal protective equipment, the Occupational Safety and Health Administration still will issue costly citations because such practice violates OSHA's blood borne pathogens standard. 
- All microbiological liquid biohazardous waste (spent liquid growth culture media containing microbial or human/nonhuman primate or other animal cells, diluted blood and tissue fluids, plasma, etc) should be autoclaved in a certified autoclave and then finally put down the sanitary sewer system
- The worker should wear personal protective equipments which include a lab coat, latex or nitrile gloves, safety glasses to protect him from spillage and aerosols generated during the disposal process
- The liquid waste should not be poured where people wash their hands and should be poured close to the surface of water so as to avoid splashing. The waste basin should be rinsed and the container disinfected after pouring of the liquid waste
- In order to assure adequate inactivation time for exposure of the liquid waste to the bleach, it is the lab supervisor's responsibility, to maintain an official log book listing each lot of biohazardous liquid waste so treated by date and notation of biohazard content (i.e., E. coli culture media, human cell cultures, etc) and exposure time (e.g., 8:00 AM to 8:00 PM). Hence, bleach treated liquids being held for inactivation in the labs must have a memo note sticker on the covering lid, showing date and time of bleach exposure (to avoid mistakes regarding the time of bleach addition). Thus, any biohazardous waste undergoing bleach inactivation and found lacking such a treatment time tag laced on to the tub cover or lacking an up to date official log book is considered to be violation of the approved inactivation process.  Such log books must be kept for a minimum of 3 years and then finally turned over to a Biosafety Office thereafter for long-term retention
- The in charge of the lab or the lab supervisor must use good judgment in using chlorine inactivation. For example, inactivation of concentrated microbial cell culture plates by disinfectants might require hours to days of exposure to still higher concentrations of (12-15%) bleach to achieve disinfection. Considering the high protein levels often present in microbial culture wastes they should be treated for at least 8 h to allow the bleach to kill the cultured microbes or any other microbial contaminants. Though the presence of a tag noting date and time of exposure will avoid mishaps and the recording of the inactivation period will ensure adequate killing time but these should be ideally autoclaved rather than sanitized
- Microbes like Legionella that can be readily transmitted to humans by aerosols should not be inactivated by bleach exposure or poured down the drain, for the generation of aerosols during such processes can infect the worker. These also need to be autoclaved; however during the process of transportation to the site for autoclaving, they should be tightly packed so as to prevent the aerosolization of legionella. Hence, spore forming microbes and pathogens that can be readily transmitted by the aerosol route should be autoclaved when present in liquid wastes. These wastes which need to be autoclaved should be directly put into the red bin.
Placing Directly in the Biohazardous Waste Bin
This is the second option where the infectious liquid waste can be placed into the red or yellow biohazard waste container depending upon the type of further treatment options as followed by the health care facility (HCF). If the HCF has an incinerator facility, then it can be placed in the yellow biohazard bin. On the other hand, if there are no incinerators then it can be placed in the red bin to be autoclaved. Typical cycle times for sterilizing liquid waste range from 45 to 90 min at 250°F and autoclave pressure should be 15 psi.
Solidification of the Liquid Waste
This process involves pouring a powdered solidifying agent into the liquid waste containers, which turns the liquid content into a gelatinous solid mass after 5 to 10 min, thus eliminates the need to transport the biohazardous fluids in a liquid form. Then these containers can be disposed of as red bag waste. The solidification process is based on a microencapsulation technology that converts liquid waste into solid waste. These are dry granular super absorbent polymers that can absorb and retain large volumes of liquids, while some solidifiers include sanitizing agents in addition, such as chlorine or glutaraldehyde, which may allow the treated medical waste to be disinfected prior to solidification.  Though they can rapidly absorb fluids up to 300 times its weight the expansion in volume is less than 1%. They can also be used to solidify and encapsulate water based spills and the disposal and transport costs are thought to be reduced by as much as 50%.
But such novel systems have some weighty problems, for a full three liter canister may weigh eight pounds after solidification. Depending on the surgical procedure a facility may use between four and eight canisters per procedure. Besides this the hospitals also need to check with their landfill operators to make sure that they will accept the solidified fluid medical waste, even if the hospital satisfies all regulatory requirements. And finally, healthcare facilities have to continually order and store bottles of solidifying powder.
The effectiveness of these powders is questionable because they have not been adequately tested on body fluids. They are considered as pesticides so the health care staff mixing the powder with the suction canister waste is not only exposed to a potential blood borne pathogen splash, but they are also exposed to a pesticide. Disposing of such suction canister waste that has been mixed with the powders also adds more pollutants to the landfills.
Closed Disposal Systems
By and large, the majority of hospitals and other healthcare facilities either pour the treated or untreated liquid waste down the drain, dispose of full or partially filled containers of liquid waste, intact as red bag waste or solidify it and then dispose of the canisters as either red or yellow bag waste if their state deems it legal.
However, the newest choice revolves around closed disposal systems that are designed to collect the fluid waste and dispose it down the sewers with minimal contact of the waste with humans. Most of them are stationary systems mounted to the floor or wall with a vacuum system that uses canisters that empties directly to the sanitary sewer, thereby can help a facility cut its infectious waste volume, reduce exposure risk
But such closed systems require a large capital expenditure upfront, which can range from $4,000 to $50,000. Apart from the cost factor such closed systems require intense labor activities, for it requires someone to collect, transport and process the waste, maintain a verification log, clean and disinfect the canisters or collectors and redistribute them. In addition, the equipment has to be maintained by the biomedical engineering department, so they have to be trained on how to use it so that they can repair it. Most of all, clinicians have also to be trained so as not to throw away the canisters or collectors. 
HCF with No Available Options
Where medical establishments cannot afford the treatment of biomedical liquid waste, the following measures should be undertaken to reduce health hazards: 
Patients with enteric diseases should be isolated in wards where their excreta can be collected in buckets for chemical disinfection. This is of utmost importance in cases of cholera outbreaks.
- No chemicals or pharmaceuticals should be discharged into the sewer
- Sludge from hospital cesspools should be dehydrated on natural drying beds and disinfected chemically with sodium hypochlorite, chlorine gas, or chlorine dioxide
- Sewage from these establishments should never be used for agriculture, aquaculture, drinking or recreational purposes.
| Disposal Procedures for Chemically Hazardous Liquid Waste|| |
Among the various hazardous waste the important ones are formaldehyde, solvents (Xylene, Acetonitrile, Acetone, Ethanol, Isopropranol, Toluene, Methanol, Ethyl acetate- obtained from pathology laboratories and during embalming procedures), mercury from broken thermometers and instruments and radioactive isotopes. 
Larger quantities of formalin are generated from pathology, autopsy, dialysis, embalming, and nursing units. The permissible exposure limits (PEL) of air borne concentration is 1 ppm over an 8 h time weighted average (TWA). Large quantities of formalin have to be incinerated for disposal.
Some of the solvents are halogenated compounds. The various unused or discarded solvents can be stored in gallon drums and then incinerated or recycled.
Radioactive wastes are usually generated from nuclear medicine department and from clinical laboratories. These materials can be retained on the site until they have been decayed to non hazardous level or they can be transported off site for land disposal.
Waste Disposal Techniques of Radioactive Isotopes Depends Upon the Levels of Radiation
Burial of radioactive waste in a built facility with no intention to retrieve the waste once the facility is closed. Some liquid waste is disposed of using the process of vitrification which encases the high radiation liquid in glass so that the liquid does not leach out during burial. 
Natural transmutation or decay
It is the conversion of one radioactive element spontaneously into another more stable element over a long period of time. Artificial transmutation can be made to occur using machines that has enough energy to cause changes in the nuclear structure of the elements.
Reuse of waste
Rreprocessing spent fuel rods can potentially recover 96% of the uranium for use in new fuel rods.
Mercury is normally generated from broken thermometers, medical devices, and dental amalgams. Because it is a powerful neurotoxin, great care must be taken to protect people from spills. Even a small quantity of mercury can lead to mercury poisoning, particularly in children. So healthcare facilities should phase out mercury devices where safer alternatives are available.
Guide to Cleaning Up a Small Mercury Spill
- Evacuate area - remove everyone from the area that has been contaminated with mercury spills and shut the door. Turn off interior ventilation system to avoid dispersing of mercury vapor 
- Put on face mask - in order to prevent breathing of mercury vapor
- Put on old clothes - so that they can be discarded if they become contaminated with mercury
- Remove jewelry - so that the mercury cannot combine (amalgamate) with the precious metals
- Wear rubber/latex/nitrile gloves - to avoid absorption through the skin. Place all broken objects in a zip lock bag. Secure the bag and label it as contaminated with mercury.
- Locate mercury beads - small and hard to see small beads can be located with the flashlight when held it at a low angle close to the floor in a darkened room which reveals glistening beads of mercury
- Use eyedropper and sticky tape - use an eyedropper or syringe (without a needle) to draw up the mercury beads and carefully transfer the mercury into an unbreakable plastic container with an airtight lid containing 5-10 ml of water. Place the container in the zip lock bag. Powdered sulfur or zinc powder when put over mercury spill, forms a colored compound which can be visualized easily
- Leak-Proof Bag - place all the materials used during the cleanup, including gloves, into a leak proof plastic bag, or container. Seal and label it
- Final disposal - contact the local hospital manager responsible for toxic cleanup and proper disposal to ensure that all mercury contaminated wastes now secured in labeled bags is dealt with in accordance with national legislation
- Outside ventilation - keep the area ventilated to the outside (with windows open and ventilation running) for at least 24 h after the successful cleanup. Still if there are symptoms of sickness, medical attention should be contacted immediately.
| Disposal Procedures for Pharmaceutical Liquid Waste|| |
These wastes account for the largest volume of waste produced by hospitals. If they are in small amounts, they can be diluted with water and discharged to the sewers. They can also either be transported off site to a secured land fill or returned to the supplier or small amounts can be incinerated. About 250 million pounds of drugs are flushed into sewage systems each year in USA.
| Disposal Procedures for Photographic Liquid Waste|| |
Temporary storage (often in 25 l containers) of such waste on-site for cartage to off-site treatment remains a necessary option, and hence obliges the staff to exercise care in storage, handling, and movement of the liquid photographic waste. Silver is a heavy metal which, in concentrations exceeding 5 ppm is considered as hazardous waste by the Resource Conservation and Recovery Act (RCRA). Silver is in highest concentrations in the fixer, so such solutions should be treated in a silver recovery unit, which removes most of the silver and is required by the PURE Code to reliably reduced silver concentration to less than 50 ppm (50 mg/L) before being disposed. Selling such wastes to authorized vendors is no doubt a better option.
Waste Water Treatment Plant
Liquid biomedical waste from the points of generation like the operation theatre, labor ward, laboratory, canteen, laundry, and toilet is segregated and disinfected and let out as effluent into a common drainage facility. This liquid waste effluent could trigger various infections and can cause disease outbreaks among the people, if they end up in the some local water bodies like lakes, rivers etc., So sensing this danger, the guidelines in the Bio Medical Waste (Management and Handling) Rules, 1998, explicitly state that, hospitals should set up their own Effluent Treatment Plants (ETPs), for treating the waste water that can eventually be reused. In hospitals that do not have ETPs, the water can be chemically treated and released into the common sewage pipeline, provided it is connected to the local municipal water treatment facilities.
This discharged waste water contains organic or inorganic solids and microbial contaminants which can be measured by the BOD and COD tests. The BOD test measures the oxygen demand of biodegradable pollutants whereas the COD test measures the oxygen demand of the oxidizable pollutants. A high BOD indicates the presence of excess amounts of organic carbon so the higher the BOD, the higher is the polluting capacity of that waste water. The permissible limit of the waste water coming out of a HCF as effluent should adhere to certain standards [Table 2]. 
This waste water is usually treated by a process that removes the majority of the contaminants and produces a liquid effluent that is suitable for both disposal to the natural environment and generation of a sludge, which can be incinerated or composted or applied directly to land as a soil amendment.
In hospitals that have ETP facility, the treatment is carried out using special scientific process and generally involves three stages, primary, secondary, and tertiary levels of treatment. 
Consists of temporarily holding the sewage in a basin where the settled and floating materials are removed and the remaining liquid subjected to secondary treatment. Primary treatment usually removes from 30 to 40% of the BOD. After this treatment the BOD and COD levels usually comes down to 25% of its initial levels.
Removes the dissolved and suspended biological matter and is typically performed by indigenous, water borne microorganisms in a managed habitat. This treatment uses microbial degradation, aerobic or anaerobic, to reduce the concentration of the organic compounds. The combined use of primary and secondary treatment reduces approximately 80 to 90% of the BOD. In this stage, there is settling down of the suspended solid contents of the biological waste as thick slurry called sludge, while the treated fluid undergoes tertiary treatment. Through this process, 95% of the pollutants from the waste water are removed.
Uses chemicals to remove inorganic compounds and pathogens. This is the final stage of treatment where the effluent after secondary treatment first is mixed with sodium hypochlorite and then the effluent is passed through dual media filter (DMF) and activated carbon filter (ACF) where sand, anthracite, and activated carbon are used as filtration media. Finally, the treated water is let into a small well to recharge the water table. This treated waste water now can be used for gardening, toilets, and laundry purposes. 
Legal Aspects of Liquid Waste Management
Indiscriminate disposal of infected and hazardous waste from hospitals, nursing homes, and pathological laboratories has led to significant degradation of the environment, leading to spread of diseases and putting the people to great risk from certain highly contagious and transmission prone disease vectors.  This has given rise to considerable environmental concern. So it is the duty of every occupier of an institution generating bio-medical waste, which includes hospitals, nursing homes, clinics, dispensaries, veterinary institution, animal houses, pathology laboratories, blood banks etc., to take all steps to ensure that such wastes are handled without any adverse effect to human health and the environment. They have to either set up their own facility or ensure requisite treatment at a common waste treatment facility or any other waste treatment facility. Each State and Union Territory Government shall be required to establish a prescribed authority for this purpose. The respective governments would also constitute advisory committees to advise the government with respect to implementation of these rules. The occupier or operator can also appeal against any order of the authority if they feel aggrieved.
| Conclusions|| |
Most existing technologies and practices are failing to deal with the problem of liquid biomedical waste, as this area of waste management is becoming grossly neglected. The hospitals and bio medical facilities though meant to ensure better health have unfortunately become a potential health risk due to mismanagement of the infectious waste. Safe handling of BMW continues to be a matter of serious concern for health authorities in India as the waste generated from medical activities can be hazardous, toxic, and even lethal because of their high potential for diseases transmission.
Because there is often a lack of awareness among hospital personnel at various levels and in the community, it becomes vital to formulate an effective communication strategy, specific to each of the target groups identified, to make them more aware of proper management of hospital waste. There is an urgent need to develop appropriate educational materials, both print and electronic, for better understanding and practice of hospital waste management.
| References|| |
|1.||Park K. Hospital Waste Management. Park′s Textbook of Preventive and Social Medicine. 18 th ed. New Delhi: M/s Banarasidas Bhanot Publications; 2005. p. 595-8. |
|2.||The Gazette of India Biomedical Wastes (Management and Handling) Rules, 1998., Extraordinary Part II Section 3-Sub Section (ii), pp. 10-20. India: Ministry of Environment and Forests, Government of India. Notification dated 20 th July, 1998. |
|3.||Blenkharn JI. Standards of clinical waste management in UK hospitals. J Hosp Infect 2006;62:300-3. |
|4.||Available from: http://www.urbanindia.nic.in/publicinfo/swm [Last assessed on 2012 Oct 24]. |
|5.||Patil AD, Shekdar AV. Health-care waste management in India. J Environ Manage 2001;63:211-20. |
|6.||Available from: http://www.c:/bisafety/liquidwaste.disposal.doc [Last assessed on 2012 Oct 24]. |
|7.||Available from: http://www.spillcontrol.ca/products/-Liquid-Waste-Solidifier [Last assessed on 2012 Oct 24]. |
|8.||Available from: http://www.baumaschine.de/baumaschine/file [Last assessed 2012 Oct 24]. |
|9.||Singh IB, Sharma RK. Hospital waste disposal system and technology. J Acad Hosp Adm 1996;8-9:33-9. |
|10.||Available from: http://blink.ucsd.edu/safety/research-lab/hazardous-waste/sewer [Last assessed on 2012 Jan 24]. |
|11.||Saling H. Radioactive Waste Management. 2 nd ed. New York: Taylor and Francis; 2002. |
|12.||Available from: http://www.epa.gov/mercury/disposal.htm [Last assessed on 2012 Oct 24]. |
|13.||Available from: http://envfor.nic.in/legis/hsm/biomed [Last assessed on 2012 Oct 24]. |
|14.||Kadam A, Ozaa G, Nemadea P, Dutta S, Shankar H. Municipal wastewater treatment using novel constructed soil filter system. Chemosphere 2008;71:975-81. |
|15.||Nemade PD, Kadam AM, Shankar HS. Wastewater renovation using constructed soil filter (CSF): A novel approach. J Hazard Mater 2009;170:657-65. |
[Table 1], [Table 2]