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Water systems in healthcare facilities
Chapter 97
Water systems in healthcare facilities Diógenes Hernández PAHO/WHO, Panama City, Panama
Introduction Water and its supply system are vital for the operation of healthcare facilities. An appropriate system for capture, storage, treatment, conditioning, use and disposal of water must be present in order to prevent hazards to patients, health professionals, and the public in general. It is also necessary to protect the installed medical and other equipment and to prevent the fast deterioration that could result from the use of inadequate or contaminated water. Water is one of the most complex resources to manage in a healthcare facility, given its implications to the health of users, the operation of the facility, and the impact on health services in general. The healthcare facility water system described here applies to both developed and developing countries. Nevertheless, differences do exist between countries regarding the availability of water through public distribution systems, water characteristics, mechanisms of capture and distribution in the facility, different uses, treatment prior to discharge, norms and standards at national and local levels, and regulations. In developed countries, agencies regulate and control water quality, particularly water used by healthcare facilities, although even developed countries include localities and rural areas with deficiencies in water supply quality. In developing countries, the lack of regulation and enforcement is common, even in urban centers. This situation is of great significance in countries vulnerable to natural disasters and extreme climatic phenomena. Natural disasters usually affect the availability, supply, and quality of the water, hindering the normal operation of a health facility. The vulnerability to natural disasters should be included as a critical factor in the process of planning a healthcare facility.
Water use cycle The water system in a healthcare facility operates through several stages. It starts with the capture of the water from the
694
municipal or public water supply system or from groundwater pumped from wells. Next, the storage, treatment, and conditioning occur, depending on the expected use by clinical and support services. Water then passes through the distribution system or piping system in the facility. The demand for water by different services and the groups of users depends on many factors but must always consider potential risks and negative impacts of water use by people (e.g., infections) and equipment (e.g., fast deterioration and damage); the collection and treatment prior to its final disposal and discharge into the sewer system, rivers, and sea; and the possible environmental impact of the water use cycle (e.g., contamination). The water use cycle, from capture from the public distribution system up to disposal, has implications for the health of the people and the community. Environmental and economic implications are inherent in the use of water. Unfortunately, water is one of the most wasted resources, and studies on the costs of water wastage are rare. Unjustified water loss costs can be high and can include water that has been treated and conditioned in order to serve the specific needs of the different healthcare facility clinical and support services. The water management plan should include responses to emergency situations relating to contaminated supply, pipe system failure, sewage system malfunction, and a water rationing program.
Planning The components and management of the water system should be defined and established when the health facility is planned and constructed. The remodeling or expansion of the physical plant presents a good opportunity to update and optimize the water system. If problems with the supply and the water quality for the different services or in critical circumstances exist, an emergency project should be established to improve the water system and its management. The size of the health facility, its level of specialization, the clinical services it provides, the installed medical Clinical Engineering Handbook. https://doi.org/10.1016/B978-0-12-813467-2.00098-5 Copyright © 2020 Elsevier Inc. All rights reserved.
Water systems in healthcare facilities Chapter | 97 695
and industrial equipment and the environmental conditions of the area where the facility is located determine the amount and characteristics of water needed. The patterns of consumption and the class of treatment that should be given to the water before and after its use and prior to its final disposal to the public sewerage system should also be considered. When planning a facility, evaluate the availability and options for water supply. Water is obtained from a public or municipal supply system, a private supplier, or a facility-owned well (borehole). The first two options are most common in urban centers. The water is usually available 24 h per day and has adequate levels of pressure and potability, making it suitable for immediate distribution and consumption within the facility. The third option is more common in rural areas or in remote regions without access to a public or municipal water supply system, or in cases of drought or prolonged periods of low rainfall leading to drying up of dams and/or rivers that normally supply municipal systems. In these cases, the implemented water supply system must guarantee the continuous availability of potable water at a pressure required for the operation of the facility. Once the water supply source is defined, determine the chemical, physical, and biological characteristics of the water at the facility entry point. Depending on the values obtained by laboratory tests, and considering the foreseen uses by the different clinical and support areas of the facility, the water must be treated and conditioned to fit specific needs and demands. This is especially important in countries that do not have regulatory agencies or the capacity to monitor and control the water system.
Design parameters The study of the water demand should be conducted for each individual healthcare facility, but some basic indicators of consumption patterns can influence the design of the facility. As a rule, a regional hospital with an average of 250 beds providing four basic specialties will have daily water consumption ranging from 450 to 600 L per bed (PAHO/CEPIS, 1996). The estimate is adjusted upward if the healthcare facility includes services or equipment with high water demand. The storage capacity for a healthcare facility depends on the specific local conditions related to water availability and distribution. The facility should have a storage capacity of 3 or 4 days in the event of a breakage or disruption in the main water line connected to the public network. If the facility does not have an adequate water supply on a regular basis, or is located in a region subject to natural disasters, the storage capacity should be increased. The facilities should have additional storage capacities when located in regions that are subject to long periods of drought, earthquakes, hurricanes, and cyclones, or prone to fire.
In designing a building’s water distribution system or piping system, areas and services that are vital for the operation of the facility will require access to reliable water even during emergency situations or main supply water breakage or disruptions. These areas should be clearly defined, and the internal supply system should be designed and constructed so that these areas always have access to water. Points of access to water should also be provided in the noncritical sectors. To guarantee adequate operation of the different areas and services in the facility, the water system should provide water with adequate quantity, flow and pressure as required to meet both human and equipment-related needs. The operation of some equipment requires specific levels of pressure and flow, and the equipment will not function if these levels are not achieved or maintained. For example, some sterilizers have valves operated by water pressure. If the valves do not have the required water pressure for activation, the equipment will function erratically, or not at all. If the public water supply system does not provide adequate pressure, or if necessary pressure cannot be produced by gravity at the facility, some areas or sectors will not have enough pressure and flow. In such cases, alternate systems must be used to provide pressure and flow to the facility distribution system. This situation is more critical in taller buildings than in shorter ones. Various engineering solutions can compensate for a lack of water pressure and flow. In healthcare facilities, especially those more horizontal than vertical, the use of elevated tanks is the most cost-effective way to achieve adequate pressure and flow. Elevated tanks should have 25%–30% of the total water storage capacity of the facility (FNH, 1981). If the characteristics, location, or safety limitations do not allow water storage in elevated tanks, other options include the use of pressure tanks or hydro-pneumatic systems that provide pressure and flow as required at different areas of the facility. Leaks are among the most common causes of water wastage. They happen due to the lack of an adequate preventive maintenance program to detect water leaks, decreased flow of water at delivery points, or a sudden and unexplained increase in water consumption by equipment or areas in the facility.
Water treatment and conditioning Water provided by a municipal or public supply system is treated to meet local, national, or international standards. In the healthcare facility, water needs additional treatment and conditioning to meet the specific needs of different users or services. The treatment procedure allows modification of the chemical composition of the water to minimize or eliminate chemical and biological contamination. This is of utmost importance in the healthcare facility since some of
696 SECTION | 10 Engineering the clinical environment
the water will be used in clinical procedures, in direct contact with patients. Before reaching the facility, the water is treated by the municipality or the public water supply agency. Water from a facility-owned well should follow the same process as that used at municipality treatment plants. The following steps are the most common in the treatment process: ●
●
●
●
●
Use of screens to remove large particulates at the intake point of the water supply. Reduction of turbidity and suspended matter; this part of the process is known as “clarification” and includes the addition of chemicals and the use of filters to remove particles larger than 25 μm. Reduction of the level of calcium and magnesium in a process known as “lime softening”; the purpose of lime softening is to minimize the hardness of the water and further clarify it. Use of chlorine gas to disinfect water with the objective of killing bacteria; the chlorine level must be constantly monitored to ensure that no harmful levels reach the population. Adjust the water pH; a pH between 7.5 and 8.0 prevents corrosion of water pipes and prevents leaching of lead into the water supply.
Once the water is delivered to the facility, it requires further treatment and conditioning to meet specific needs. The processes needed for further treatment vary with the end user water requirements. Some treatment processes minimize risks and protect people, while others protect equipment. Some of the more common steps in on-site treatment and conditioning are as follows: ●
●
●
●
Removal of particulates larger than 20 μm using sediment filtration, followed by removal of particulates larger than 10 μm using multimedia filtration. Adjustment of the water pH to prevent damage of pHsensitive materials; for example, adjustment of the pH to a level between 8.3 and 9.0 to prevent acid corrosion in boilers. Adding chemicals to soften the water in order to prevent hardness and the deposition of calcium, magnesium, ferrous, manganese, and aluminum. Removal of chloramines, chlorines, and other low molecular weight organic chemicals using carbon beds.
Options to treat and condition water to suit specific needs are as follows: ●
Use of filters. Sand filters remove turbidity but cannot stop smaller impurities from passing through. Calcium carbonate calcite medium filters (also known as neutralizing fitters) neutralize low-pH water. Activated carbon filters absorb low-molecular-weight organic chemicals and reduce chlorine or other halogens from water, but they do not remove any salts. There are several types
●
of disposable filters to trap fine particles in the range of 1–100 μm, and ultrafiltration solutions remove particles in the range of 0.005–0.15 μm. Reverse osmosis (RO). RO is a crossflow membrane separation process that removes virtually all organic compounds (Osmonics, 1992). A large selection of RO membranes is available to remove most particles and microorganisms.
For specific clinical procedures such as hemodialysis, water must be further conditioned for patient use (ECRI, 1991). Some methods for additional conditioning are as follows: ●
●
●
●
Removal of salts, bacteria, pyrogens, metal ions, and particles using RO filters. Removal of charged particles such as metals and ions using deionization. Removal of bacteria, pyrogens, and particles larger than 0.05 μm using ultrafiltration. Use of ultraviolet light to kill microorganisms.
The main centers of water consumption should be determined based on the volume of water to be treated and the different requirements of end users. For example, water treatment plants must be built for water to be used in boilers for steam production and water used in the laundry service. However, for use in laboratories and clinical areas, water can be obtained by filtering, adding chemicals, via distillation or the use of other special equipment. In order to prevent outbreaks and nosocomial infections, protocols for water use should be part of a risk management program. Some common problems include infections from rinsing equipment with potable water, rinsing burn patients with tap water, and preparing baby formulas with tap water. A water quality control system should be implemented to avoid these problems.
End users Most healthcare facilities have six major areas of water consumption: sanitation; heating, ventilation, and air conditioning (HVAC); clinical and medical; laundry; food service; and miscellaneous uses. Sanitation and HVAC consume approximately 60% of the water in most facilities. Water use should not include the water required for the fire extinguishing system; this water is normally raw or untreated and it is stored in a separate tank. The main end users of water are patients and healthcare workers, clinical and support services, and the building itself. Most of the water used by patients and healthcare workers is for drinking and personal hygiene. Water is used in many clinical services areas including the following: ●
Clinical and pathology laboratories: Laboratories perform many operations with different types of equipment. Water is used and discharged by automated laboratory
Water systems in healthcare facilities Chapter | 97 697
●
●
●
●
●
●
e quipment, water baths, emergency showers, eyewash stations, and sinks. Some of the common pollutants in wastewater include solvents, mercury (Eppstein, 2000), zinc and other heavy metals, strong acids and toxic chemicals, radionuclides, proteins, blood products, and body fluids. X-ray department: X-ray film processors (less and less common with the move to computerized/digital radiography) need water; ammonia and developer products are the most common chemical pollutants in film processor wastewater. Dental services: The handheld tools in the dental care unit consume most of the water; the equipment water lines and cold wastewater from these tools become contaminated with microorganisms. Respiratory therapy department: Respiratory care equipment, nebulizers, and humidifiers use most of the water. Central supply and sterilization department: Water is used to clean and disinfect surgical instruments in conjunction with ethylene oxide sterilization; some of the more common effluent pollutants are soap, detergent, disinfectants, and ethylene oxide. Operating theaters and emergency rooms: Water is used in surgical scrub sinks, where blood, body fluids, and glutaraldehyde can pollute the wastewater. Other areas with significant water usage include the pharmacy, for the preparation of formulas and parenteral solutions, and the physiotherapy unit (hydrotherapy equipment); both of these areas are susceptible to infection and contamination. Water is used in the following support services areas:
●
●
●
●
●
HVAC system: Cooling towers and humidifiers are heavy consumers of nonpotable water. Boiler House: Boilers and hot water tanks consume large quantities of water; water treatment chemicals and oils are common pollutants. Laundry service: Washing machines are large consumers of water. An efficient operational policy supported by a preventive maintenance program can save water and the costs associated with its use and discharge in the laundry. Some of the more common pollutants are soaps, detergents, and bleaches. Food services and kitchen: Sinks, dishwashers, ice makers, and food preparation are users of water. Soaps, detergents, disinfectants, solvents, pesticides, and cleaning solutions are among the common pollutants. Medical waste incinerators: The most common pollutants are heavy metals and particulate matter.
Water used in the physical plant includes the following areas: ●
Sanitary: Sinks, toilets, showers, and bathtubs all consume water; improper cleaning procedures will allow bacterial growth and contamination.
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●
Housekeeping: Cleaning and disinfecting will generate pollutants from soaps, detergents, cleaners, solvents, and disinfectants. Physical plant maintenance activities will generate pollutants from paint, adhesives, soaps, detergents, solvents, and oils.
Wastewater Wastewater collected from different facility services and end users carries a variety of chemical and biological pollutants, several of which are hazardous. Wastewater should be included in a facility’s water management and water quality program and should be closely monitored and pretreated prior to its discharge into the public or municipal sewer system. Some developed countries have pretreatment standards and guidelines for healthcare facilities’ wastewater; others apply pretreatment standards established for industrial waste disposal. Developing countries might need to strengthen their capacities for monitoring and controlling healthcare facilities’ wastewater.
Conclusions Water systems have profound implications for the performance of healthcare facilities and the expected outcomes of healthcare processes and procedures. Facilities should have adequate management and quality control system for used and discharged water in order to prevent problems for people, equipment, and the environment. From the health perspective, water is one of the main sources of nosocomial infections (Rutala and Weber, 1997) and from the engineering perspective, one of the main causes of equipment deterioration and breakdown. Water is a strategic energy resource that should be used and managed efficiently. Water waste or improper usage and disposal have a negative environmental impact and an adverse economic effect because of the resource expended in the costly process of treatment and conditioning. Protection of the environment is an increasing concern worldwide. Governments and society are looking more closely into issues that negatively affect the environment. Usage and disposal of water in healthcare facilities is one of those issues, especially for developing countries where health care is part of a small industrial sector but is one of the larger consumers of water.
Acknowledgment The author thanks his friend and colleague, Antonio Hernandez, for the considerable time and effort he expended in assisting with the writing of this chapter. Antonio is (former) Regional Advisor on Health Services, Pan American Health Organization/World Health Organization (PAHO/WHO), Washington, DC.
698 SECTION | 10 Engineering the clinical environment
References ECRI, 1991. Hemodialysis machines. Health Devices Systems vol. 20 (6). Eppstein, D., 2000. MASCO. Mercury Work Group, Boston. Fondo Nacional Hospitalario/Ministerio de Salud, 1981. Aspectos Básicos para el Diseño de Areas Específicas en Instituciones Hospitalarias. In: Bogota, Colombia, VI Seminario Nacional I Simposio Internacional de Arquitectura Hospitalaria. Osmonics, Inc, 1992. Pure Water Osmonics Handbook. Osmonics Inc., Minnetonka, MN. Pan American Health Organization, 1996. Centro Panamericano de Ingeniería Sanitaria y Ciencias del Ambiente (Publicación No. 96.23). In: Estudio de caso: terremoto del 22 de abril de 1991. Limón, Costa Rica. Lima: OPS/CEPIS. Rutala, W.A., Weber, D.J., 1997. Water as a reservoir of nosocomial pathogens. Infect. Control Hospit. Epidemiol. J. 18, 9.
Resources General American Society of Plumbing Engineers, 2001. Chapter 1: Fire-protection systems; Chapter 2: Plumbing design for health-care facilities. In: A Plumbing Engineer’s Guide to System Design and Specifications— Data Bool. Vol. 3: Special Plumbing Systems. American Society of Plumbing Engineers, Chicago.
Water safety and quality World Health Organization, 2017. Guidelines for Drinking-Water Quality, fourth ed.. Water safety plan manual: Step-by-step risk management for drinking-water suppliers (2009); Water safety plan: A field guide to improving drinking-water safety in small communities (2014); Protecting groundwater for health: Managing the quality of drinkingwater sources (2006); Protecting surface water for health: Identifying,
assessing and managing drinking-water quality risks in surface-water catchments (2016); Water safety in buildings (2011); Water and sanitation for health facility improvement tool (WASH FIT): A practical guide for improving quality of care through water, sanitation and hygiene in health-care facilities. WHO & UNICEF (2017); etc. See https://www.who.int/water_sanitation_health/water-quality/en/ (accessed April 2019). The control of Legionella, hygiene, “safe” hot water, cold water and drinking water systems: Part A: Design, installation and testing, 2006. Health Technical Memorandum 04-01. Estates and Facilities Directorate, Department of Health, United Kingdom. NHS Health Technical Memorandum (HTM) 04, 2013. Water systems; Safe water in healthcare premises (HTM 04-01), 2017; (Part A: Design, installation and commissioning; Part B: Operational management; Part C: Pseudomonas aeruginosa—advice for augmented care units; Part D: Performance specification D 08: thermostatic mixing valves (healthcare premises)). Water management and water efficiency (HTM 07-04). See https://www.gov.uk/government/collections/ health-technical-memorandum-disinfection-and-sterilization (accessed April 2019).
Water and hemodialysis ANSI/AAMI 13959, 2014. Water for hemodialysis and related therapies. ANSI/AAMI 26722, 2014. Water treatment equipment for hemodialysis applications and related therapies. Payne, G., 2014. AAMI Dialysis Water and Dialysate Recommendations: A User Guide. ISO 23500-3, 2019. Preparation and quality management of fluids for haemodialysis and related therapies—Part 3: Water for haemodialysis and related therapies. Agency for Clinical Innovation, 2018. Water for dialysis—A guide for incentre, satellite and home haemodialysis in NSW. NSW Government, Australia. Coulliette, A.D., Arduino, M.J., 2013. Hemodialysis and water quality. Semin. Dial. 26 (4), 427–438. https://doi.org/10.1111/sdi.12113.
Water systems in healthcare facilities Diógenes Hernández PAHO/WHO, Panama City, Panama
Introduction Water and its supply system are vital for the operation of healthcare facilities. An appropriate system for capture, storage, treatment, conditioning, use and disposal of water must be present in order to prevent hazards to patients, health professionals, and the public in general. It is also necessary to protect the installed medical and other equipment and to prevent the fast deterioration that could result from the use of inadequate or contaminated water. Water is one of the most complex resources to manage in a healthcare facility, given its implications to the health of users, the operation of the facility, and the impact on health services in general. The healthcare facility water system described here applies to both developed and developing countries. Nevertheless, differences do exist between countries regarding the availability of water through public distribution systems, water characteristics, mechanisms of capture and distribution in the facility, different uses, treatment prior to discharge, norms and standards at national and local levels, and regulations. In developed countries, agencies regulate and control water quality, particularly water used by healthcare facilities, although even developed countries include localities and rural areas with deficiencies in water supply quality. In developing countries, the lack of regulation and enforcement is common, even in urban centers. This situation is of great significance in countries vulnerable to natural disasters and extreme climatic phenomena. Natural disasters usually affect the availability, supply, and quality of the water, hindering the normal operation of a health facility. The vulnerability to natural disasters should be included as a critical factor in the process of planning a healthcare facility.
Water use cycle The water system in a healthcare facility operates through several stages. It starts with the capture of the water from the
694
municipal or public water supply system or from groundwater pumped from wells. Next, the storage, treatment, and conditioning occur, depending on the expected use by clinical and support services. Water then passes through the distribution system or piping system in the facility. The demand for water by different services and the groups of users depends on many factors but must always consider potential risks and negative impacts of water use by people (e.g., infections) and equipment (e.g., fast deterioration and damage); the collection and treatment prior to its final disposal and discharge into the sewer system, rivers, and sea; and the possible environmental impact of the water use cycle (e.g., contamination). The water use cycle, from capture from the public distribution system up to disposal, has implications for the health of the people and the community. Environmental and economic implications are inherent in the use of water. Unfortunately, water is one of the most wasted resources, and studies on the costs of water wastage are rare. Unjustified water loss costs can be high and can include water that has been treated and conditioned in order to serve the specific needs of the different healthcare facility clinical and support services. The water management plan should include responses to emergency situations relating to contaminated supply, pipe system failure, sewage system malfunction, and a water rationing program.
Planning The components and management of the water system should be defined and established when the health facility is planned and constructed. The remodeling or expansion of the physical plant presents a good opportunity to update and optimize the water system. If problems with the supply and the water quality for the different services or in critical circumstances exist, an emergency project should be established to improve the water system and its management. The size of the health facility, its level of specialization, the clinical services it provides, the installed medical Clinical Engineering Handbook. https://doi.org/10.1016/B978-0-12-813467-2.00098-5 Copyright © 2020 Elsevier Inc. All rights reserved.
Water systems in healthcare facilities Chapter | 97 695
and industrial equipment and the environmental conditions of the area where the facility is located determine the amount and characteristics of water needed. The patterns of consumption and the class of treatment that should be given to the water before and after its use and prior to its final disposal to the public sewerage system should also be considered. When planning a facility, evaluate the availability and options for water supply. Water is obtained from a public or municipal supply system, a private supplier, or a facility-owned well (borehole). The first two options are most common in urban centers. The water is usually available 24 h per day and has adequate levels of pressure and potability, making it suitable for immediate distribution and consumption within the facility. The third option is more common in rural areas or in remote regions without access to a public or municipal water supply system, or in cases of drought or prolonged periods of low rainfall leading to drying up of dams and/or rivers that normally supply municipal systems. In these cases, the implemented water supply system must guarantee the continuous availability of potable water at a pressure required for the operation of the facility. Once the water supply source is defined, determine the chemical, physical, and biological characteristics of the water at the facility entry point. Depending on the values obtained by laboratory tests, and considering the foreseen uses by the different clinical and support areas of the facility, the water must be treated and conditioned to fit specific needs and demands. This is especially important in countries that do not have regulatory agencies or the capacity to monitor and control the water system.
Design parameters The study of the water demand should be conducted for each individual healthcare facility, but some basic indicators of consumption patterns can influence the design of the facility. As a rule, a regional hospital with an average of 250 beds providing four basic specialties will have daily water consumption ranging from 450 to 600 L per bed (PAHO/CEPIS, 1996). The estimate is adjusted upward if the healthcare facility includes services or equipment with high water demand. The storage capacity for a healthcare facility depends on the specific local conditions related to water availability and distribution. The facility should have a storage capacity of 3 or 4 days in the event of a breakage or disruption in the main water line connected to the public network. If the facility does not have an adequate water supply on a regular basis, or is located in a region subject to natural disasters, the storage capacity should be increased. The facilities should have additional storage capacities when located in regions that are subject to long periods of drought, earthquakes, hurricanes, and cyclones, or prone to fire.
In designing a building’s water distribution system or piping system, areas and services that are vital for the operation of the facility will require access to reliable water even during emergency situations or main supply water breakage or disruptions. These areas should be clearly defined, and the internal supply system should be designed and constructed so that these areas always have access to water. Points of access to water should also be provided in the noncritical sectors. To guarantee adequate operation of the different areas and services in the facility, the water system should provide water with adequate quantity, flow and pressure as required to meet both human and equipment-related needs. The operation of some equipment requires specific levels of pressure and flow, and the equipment will not function if these levels are not achieved or maintained. For example, some sterilizers have valves operated by water pressure. If the valves do not have the required water pressure for activation, the equipment will function erratically, or not at all. If the public water supply system does not provide adequate pressure, or if necessary pressure cannot be produced by gravity at the facility, some areas or sectors will not have enough pressure and flow. In such cases, alternate systems must be used to provide pressure and flow to the facility distribution system. This situation is more critical in taller buildings than in shorter ones. Various engineering solutions can compensate for a lack of water pressure and flow. In healthcare facilities, especially those more horizontal than vertical, the use of elevated tanks is the most cost-effective way to achieve adequate pressure and flow. Elevated tanks should have 25%–30% of the total water storage capacity of the facility (FNH, 1981). If the characteristics, location, or safety limitations do not allow water storage in elevated tanks, other options include the use of pressure tanks or hydro-pneumatic systems that provide pressure and flow as required at different areas of the facility. Leaks are among the most common causes of water wastage. They happen due to the lack of an adequate preventive maintenance program to detect water leaks, decreased flow of water at delivery points, or a sudden and unexplained increase in water consumption by equipment or areas in the facility.
Water treatment and conditioning Water provided by a municipal or public supply system is treated to meet local, national, or international standards. In the healthcare facility, water needs additional treatment and conditioning to meet the specific needs of different users or services. The treatment procedure allows modification of the chemical composition of the water to minimize or eliminate chemical and biological contamination. This is of utmost importance in the healthcare facility since some of
696 SECTION | 10 Engineering the clinical environment
the water will be used in clinical procedures, in direct contact with patients. Before reaching the facility, the water is treated by the municipality or the public water supply agency. Water from a facility-owned well should follow the same process as that used at municipality treatment plants. The following steps are the most common in the treatment process: ●
●
●
●
●
Use of screens to remove large particulates at the intake point of the water supply. Reduction of turbidity and suspended matter; this part of the process is known as “clarification” and includes the addition of chemicals and the use of filters to remove particles larger than 25 μm. Reduction of the level of calcium and magnesium in a process known as “lime softening”; the purpose of lime softening is to minimize the hardness of the water and further clarify it. Use of chlorine gas to disinfect water with the objective of killing bacteria; the chlorine level must be constantly monitored to ensure that no harmful levels reach the population. Adjust the water pH; a pH between 7.5 and 8.0 prevents corrosion of water pipes and prevents leaching of lead into the water supply.
Once the water is delivered to the facility, it requires further treatment and conditioning to meet specific needs. The processes needed for further treatment vary with the end user water requirements. Some treatment processes minimize risks and protect people, while others protect equipment. Some of the more common steps in on-site treatment and conditioning are as follows: ●
●
●
●
Removal of particulates larger than 20 μm using sediment filtration, followed by removal of particulates larger than 10 μm using multimedia filtration. Adjustment of the water pH to prevent damage of pHsensitive materials; for example, adjustment of the pH to a level between 8.3 and 9.0 to prevent acid corrosion in boilers. Adding chemicals to soften the water in order to prevent hardness and the deposition of calcium, magnesium, ferrous, manganese, and aluminum. Removal of chloramines, chlorines, and other low molecular weight organic chemicals using carbon beds.
Options to treat and condition water to suit specific needs are as follows: ●
Use of filters. Sand filters remove turbidity but cannot stop smaller impurities from passing through. Calcium carbonate calcite medium filters (also known as neutralizing fitters) neutralize low-pH water. Activated carbon filters absorb low-molecular-weight organic chemicals and reduce chlorine or other halogens from water, but they do not remove any salts. There are several types
●
of disposable filters to trap fine particles in the range of 1–100 μm, and ultrafiltration solutions remove particles in the range of 0.005–0.15 μm. Reverse osmosis (RO). RO is a crossflow membrane separation process that removes virtually all organic compounds (Osmonics, 1992). A large selection of RO membranes is available to remove most particles and microorganisms.
For specific clinical procedures such as hemodialysis, water must be further conditioned for patient use (ECRI, 1991). Some methods for additional conditioning are as follows: ●
●
●
●
Removal of salts, bacteria, pyrogens, metal ions, and particles using RO filters. Removal of charged particles such as metals and ions using deionization. Removal of bacteria, pyrogens, and particles larger than 0.05 μm using ultrafiltration. Use of ultraviolet light to kill microorganisms.
The main centers of water consumption should be determined based on the volume of water to be treated and the different requirements of end users. For example, water treatment plants must be built for water to be used in boilers for steam production and water used in the laundry service. However, for use in laboratories and clinical areas, water can be obtained by filtering, adding chemicals, via distillation or the use of other special equipment. In order to prevent outbreaks and nosocomial infections, protocols for water use should be part of a risk management program. Some common problems include infections from rinsing equipment with potable water, rinsing burn patients with tap water, and preparing baby formulas with tap water. A water quality control system should be implemented to avoid these problems.
End users Most healthcare facilities have six major areas of water consumption: sanitation; heating, ventilation, and air conditioning (HVAC); clinical and medical; laundry; food service; and miscellaneous uses. Sanitation and HVAC consume approximately 60% of the water in most facilities. Water use should not include the water required for the fire extinguishing system; this water is normally raw or untreated and it is stored in a separate tank. The main end users of water are patients and healthcare workers, clinical and support services, and the building itself. Most of the water used by patients and healthcare workers is for drinking and personal hygiene. Water is used in many clinical services areas including the following: ●
Clinical and pathology laboratories: Laboratories perform many operations with different types of equipment. Water is used and discharged by automated laboratory
Water systems in healthcare facilities Chapter | 97 697
●
●
●
●
●
●
e quipment, water baths, emergency showers, eyewash stations, and sinks. Some of the common pollutants in wastewater include solvents, mercury (Eppstein, 2000), zinc and other heavy metals, strong acids and toxic chemicals, radionuclides, proteins, blood products, and body fluids. X-ray department: X-ray film processors (less and less common with the move to computerized/digital radiography) need water; ammonia and developer products are the most common chemical pollutants in film processor wastewater. Dental services: The handheld tools in the dental care unit consume most of the water; the equipment water lines and cold wastewater from these tools become contaminated with microorganisms. Respiratory therapy department: Respiratory care equipment, nebulizers, and humidifiers use most of the water. Central supply and sterilization department: Water is used to clean and disinfect surgical instruments in conjunction with ethylene oxide sterilization; some of the more common effluent pollutants are soap, detergent, disinfectants, and ethylene oxide. Operating theaters and emergency rooms: Water is used in surgical scrub sinks, where blood, body fluids, and glutaraldehyde can pollute the wastewater. Other areas with significant water usage include the pharmacy, for the preparation of formulas and parenteral solutions, and the physiotherapy unit (hydrotherapy equipment); both of these areas are susceptible to infection and contamination. Water is used in the following support services areas:
●
●
●
●
●
HVAC system: Cooling towers and humidifiers are heavy consumers of nonpotable water. Boiler House: Boilers and hot water tanks consume large quantities of water; water treatment chemicals and oils are common pollutants. Laundry service: Washing machines are large consumers of water. An efficient operational policy supported by a preventive maintenance program can save water and the costs associated with its use and discharge in the laundry. Some of the more common pollutants are soaps, detergents, and bleaches. Food services and kitchen: Sinks, dishwashers, ice makers, and food preparation are users of water. Soaps, detergents, disinfectants, solvents, pesticides, and cleaning solutions are among the common pollutants. Medical waste incinerators: The most common pollutants are heavy metals and particulate matter.
Water used in the physical plant includes the following areas: ●
Sanitary: Sinks, toilets, showers, and bathtubs all consume water; improper cleaning procedures will allow bacterial growth and contamination.
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Housekeeping: Cleaning and disinfecting will generate pollutants from soaps, detergents, cleaners, solvents, and disinfectants. Physical plant maintenance activities will generate pollutants from paint, adhesives, soaps, detergents, solvents, and oils.
Wastewater Wastewater collected from different facility services and end users carries a variety of chemical and biological pollutants, several of which are hazardous. Wastewater should be included in a facility’s water management and water quality program and should be closely monitored and pretreated prior to its discharge into the public or municipal sewer system. Some developed countries have pretreatment standards and guidelines for healthcare facilities’ wastewater; others apply pretreatment standards established for industrial waste disposal. Developing countries might need to strengthen their capacities for monitoring and controlling healthcare facilities’ wastewater.
Conclusions Water systems have profound implications for the performance of healthcare facilities and the expected outcomes of healthcare processes and procedures. Facilities should have adequate management and quality control system for used and discharged water in order to prevent problems for people, equipment, and the environment. From the health perspective, water is one of the main sources of nosocomial infections (Rutala and Weber, 1997) and from the engineering perspective, one of the main causes of equipment deterioration and breakdown. Water is a strategic energy resource that should be used and managed efficiently. Water waste or improper usage and disposal have a negative environmental impact and an adverse economic effect because of the resource expended in the costly process of treatment and conditioning. Protection of the environment is an increasing concern worldwide. Governments and society are looking more closely into issues that negatively affect the environment. Usage and disposal of water in healthcare facilities is one of those issues, especially for developing countries where health care is part of a small industrial sector but is one of the larger consumers of water.
Acknowledgment The author thanks his friend and colleague, Antonio Hernandez, for the considerable time and effort he expended in assisting with the writing of this chapter. Antonio is (former) Regional Advisor on Health Services, Pan American Health Organization/World Health Organization (PAHO/WHO), Washington, DC.
698 SECTION | 10 Engineering the clinical environment
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