Selected Highlights of the Labs21 2007 Annual Conference

It's Not All About Air

Water Usage for Containment Protocols and Sterilization are Major Sustainability Challenges in Large Animal Containment Facilities

Bradley Andersen and Kevin Breslin, Merrick & Company

Introduction

Laboratories have traditionally been identified as "energy hogs" due to programmatic requirements for single-pass air. Domestic water uses, personnel showers, animal room and animal penning/cage washdown, autoclave use, and other programmatic needs account for over 95 percent of the water usage in these facilities. Water heating and sterilization is a significant portion of a laboratory facility's energy usage, with washdown and sterilization accounting for more than 90 percent of the non-HVAC usage.

Accordingly, major reductions in water and energy usage can be accomplished through intelligent application of established sustainability principles. This paper uses the USDA's newly completed Large Animal Facility at the National Centers for Animal Health in Ames, Iowa, as a case study.

Water Usage in a Large Animal Containment Facility

Domestic uses of water at the Large Animal Facility include drinking water, handwashing, and sanitary waste streams (urinals and toilets). Programmatic water uses include personnel showers (mandatory for exiting the animal rooms and high-containment areas; program-driven for animal room entrance), animal room washdown (including washdown of large animals where required), and drain trap maintenance. Sterilization uses include autoclaves and high-pressure carcass rendering. Water heating and sterilization needs also account for a significant portion of the facility's energy usage. These uses include handwashing, personnel showers, animal room washdown, and sterilization. At the Ames, Iowa, Large Animal Facility, programmatic needs account for over 95 percent of the water usage and over 90 percent of the non-HVAC energy usage. Water and energy use are summarized in the table below:

Water and energy usage summary table.

Strategies for reducing water and water heating energy use include grey water recovery, reduction of shower and animal room washdown duration, and substitution of antiseptic sterilization for hot water sterilization. Additionally, opportunities exist for heat recovery from the condensate systems for domestic water preheat. Strategies for water and energy use reduction are listed below:

Water Use

Strategy for Water/Energy Use Reduction

Discussion of Advantages, Disadvantages and Cautions

Drinking Water

Replace electric water coolers with bottled water

This strategy would eliminate all built-in water coolers and replace them with bottled water coolers. Traditional water coolers typically waste two-thirds of their water in use. Energy savings by reduction of chilled water use would also be realized.

Handwashing

Hand sanitizer to supplement handwashing procedures

This strategy would supplement current handwashing procedures with a regimen of handwashing and hand sanitizer usage. The intent would be to reduce the duration of hand washing needed to remove dirt and debris from hands and rely on antiseptic sanitizers for final cleansing. This strategy should be evaluated by the facility Health and Safety Officer and would require training to ensure proper safeguards are maintained.

Sanitary Waste Streams

Dual flush water closets and waterless urinals

This strategy would use state-of-the-art water-saving fixtures to reduce domestic water usage for waste streams. There is little or no first cost premium in using these fixtures. However, janitorial and maintenance staff must be trained in their cleaning and maintenance to ensure continued user satisfaction.

Grey water recovery

Grey water recovery systems typically process lavatory and shower waste streams for non-potable reuse. However, in a biocontainment facility, waste streams within containment cannot safely be reused. Therefore, grey water recovery within this facility must be limited to those fixtures outside of containment. One easily implemented type of grey water device is the cascading type lavatory/water closet fixture. This fixture collects the lavatory waste into the water closet tank for use in subsequent flushes. Unfortunately, this fixture does not support flushvalve type water closets. Therefore, a change in fixture type would be required to support this strategy.

Stormwater recovery

A stormwater recovery system would collect stormwater from building roof drains and eaves into an underground basin. The water would then be filtered and pumped throughout the building for non-potable uses. This strategy could be combined with a grey water recovery system (as described above) for additional recovery. The recovery system would require some usable floor space for treatment and does require significant first cost to implement.

Personnel Showers

Shorter duration showers

This strategy would implement shorter duration (four-minute in lieu of five-minute) showers, reducing both water and water heating energy usage. However, this strategy must be evaluated by the facility Health and Safety Officer for suitability with the accepted agent-handling protocols. Training of facility staff would be required to ensure continued human and animal safety.

Lower temperature showers

This strategy would implement lower temperature (90°F in lieu of 95°F) showers, reducing water heating energy usage. Care should be taken to ensure that user comfort is maintained.

Single vs. dual showers

Current protocol at the Ames, Iowa, facility is to shower out from the animal and necropsy rooms and then shower out again when exiting containment. However, the second shower might be eliminated because the typical exit from the facility is through the clean side of containment. Eliminating the second shower would reduce both water and water heating energy usage. This strategy must be evaluated by the facility Health and Safety Officer and could be altered as needed for high-risk events.

Combined strategy

The three strategies outlined above can be combined for maximum water and energy savings (i.e., four-minute duration, 90°F showers, only when exiting the animal and necropsy rooms).

Animal Room Washdown

Two-phase washdown (four-minute cold rinse followed by one-minute hot wash)

Current facility design assumes a five-minute washdown duration of 180°F hot water with the intent of removing debris and waste from the animal rooms. This strategy proposes an initial four-minute cold water washdown to remove most of the debris and waste. The cold washdown will be followed by a reduced (one-minute) hot washdown to remove any remaining stubborn debris.

Manual removal of solid waste followed by hot wash

With this strategy, the majority of the debris removal would be accomplished by shoveling the waste into a sealed bag for off-site decontamination. Manual waste removal would be followed by a reduced (two-minute) hot washdown to remove any remaining debris.

High-pressure wash (Hotsy or similar)

Washdown duration can also be reduced by the use of a high-pressure wash system (Hotsy or similar). This strategy would use a three-minute cold washdown for major debris removal followed by a one-minute high-pressure washdown of remaining waste. This strategy must be evaluated by the facility Health and Safety Officer and is not suitable where aerosolized contaminants pose a health risk to humans or animals.

Combined strategy

The three strategies outlined above can be combined for maximum water and energy savings (i.e., manual waste removal followed by a one-minute cold washdown and one-minute high-pressure hot washdown). It should be noted that manual removal of animal waste will increase the room cleaning duration by about five minutes.

Autoclaves

Substitute antiseptic sterilization where applicable

Most of the product and equipment sterilization at the Ames, Iowa, facility is accomplished with steam autoclave units. Significant reductions in energy use may be accomplished by substituting antiseptic sterilization (via dunk tanks or antiseptic pass boxes) for steam sterilization in 50 percent of the uses. This strategy must be evaluated by the facility Health and Safety Officer for compliance with infectious agent protocol.

Substitute air seals for steam seals at doors

Currently, steam is used to pressurize the sterilizer door seals. This strategy proposes to use compressed air for door seals instead of steam, reducing energy usage. This strategy must be evaluated by the facility Health and Safety Officer to ensure there is no health risk through an unsterilized door seal.

Carcass Renderers

Recovery of coolant water

Domestic cold water is used in the renderer hot well for cooling the steam/condensate and is dumped to drain. This proposal would recover the coolant water to a tank, where it could be reused for the next cooling cycle. Energy savings may also be realized through a domestic water preheat/heat recovery loop (see below). Additional floor space and first cost would be required to implement this strategy.

Substitute air seals for steam seals at doors

Currently, steam is used to pressurize the sterilizer door seals. This strategy proposes to use compressed air for door seals instead of steam, reducing energy usage. This strategy must be evaluated by the facility Health and Safety Officer to ensure there is no health risk through an unsterilized door seal.

Heat Recovery

Provide separated loop heat recovery for domestic water preheat

Much of the waste heat in this facility is released through contaminated waste streams. A separated loop heat recovery system would help recover much of the energy for utilization in low heat applications (e.g., domestic water preheat) and would help cool hot waste streams for entry into the sewer system.

Program Modification

Where applicable, facilitate batch processing of sterilization and tissue rendering

Although no specific modifications are identified here, facility personnel can be instructed to examine existing processes and identify procedures that may benefit from batch processing of material (i.e., tissue waste rendering or product sterilization).

Recovery of condensate water

The Ames, Iowa, facility relies on the campus steam plant for steam production and condensate return. Currently, the steam plant is not able to re-process the condensate from the facility and it must be wasted to sewer. Significant water and energy savings can be realized by modifying the central plant operating procedures to accommodate condensate return. Additional savings in maintenance costs at the steam boilers would also be realized by recovery of the steam condensate.

Analysis

Implementation of these strategies results in an estimated cumulative savings of almost 1.3 million gallons of water (66 percent) annually, equating to approximately $2,200 per year at local water rates. The greatest water usage reduction occurs with the animal room washdown strategy accounting for more than half of the overall water usage savings. Although there will be longer room cleaning durations (shoveling animal waste and debris will extend room cleaning time), the water and energy savings will help to offset the added soft costs. It should also be noted that current campus steam protocol prohibits the facility from returning the digester and sterilizer condensate, resulting in an abnormally high water use for these systems. Additional savings are realized by reclamation of the steam condensate at the sterilizers and tissue renderers. The remaining needs account for approximately 18 percent of the water use reduction.

Annual water usage chart.

The cumulative energy benefit of these strategies is an estimated 6.8 thousand Therms (65 percent) per year, equating to approximately $47,000 per year at an assumed cost of $7.00 per Therm. The greatest energy usage reduction occurs with the animal room washdown strategy. Approximate savings of 1,200 Therms are achievable by substituting antiseptic sterilization for 50 percent of the steam sterilization at the autoclave units. Heat recovery would add approximately 340 Therms in energy savings through domestic water preheat.

Annual water heating energy chart.

Conclusions

Given the normally high usage of water required for the washdown of animal rooms, the best opportunity for reduction of water usage in a high-containment animal facility will result from a washdown protocol that can accomplish the washdown using a combination of manual debris removal and high-pressure/low flow devices to remove and dispose of debris. Because these will vary in each facility, the floor and wall finishes and type and volume of debris need to prevent aerosolization, and available manpower must be evaluated in each case to arrive at the optimum, most water and energy-efficient washdown protocol. Especially in high containment facilities, the need to review and arrive at acceptable protocols with the bio-safety office is paramount.

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Biographies

Bradley Andersen is Vice President and Senior Project Manager at Merrick & Company and leads Merrick's Life Sciences team. He manages the planning and design of large, technically complex, multidiscipline projects, focusing primarily on institutional and laboratory facilities. Mr. Andersen is a licensed architect and holds a graduate architecture degree from the University of Washington and an undergraduate degree from Brigham Young University.  He began work at Merrick & Company in 1989 and during his tenure there managed significant life science projects including the $70 million BSL3-Ag High Containment facility for Large Animals at USDA's National Centers for Animal Health, the National Seed Storage Laboratory in Fort Collins, Colorado, and numerous laboratory facilities for the Department of Agriculture, the Department of Interior, and the National Renewable Energy Laboratory in Golden, Colorado.  He works closely with operations and research staffs to maximize the sustainability and cost-benefit in their project designs.

 

Kevin Breslin is the Lead Mechanical Engineer at Merrick & Company and resides in Aurora, Colorado. Kevin has over 25 years of experience in the design of commercial, institutional, and governmental facilities and is a registered Mechanical and Fire Protection Engineer, a LEED® Accredited Professional, and a Certified Energy Manager through the Association of Energy Engineers. He has participated in the design of many life-science laboratories, including the USDA Large Animal Lab at the National Centers for Animal Health in Ames, Iowa, and the National Seed Storage Laboratory in Fort Collins, Colorado. Kevin has also consulted in the commissioning phases of several bio-containment facilities, including the National Emerging Infectious Diseases Laboratory in Boston, Massachusetts. Merrick & Company is a multi-disciplinary architectural-engineering firm based in Aurora, Colorado, and has offices in Atlanta, Albuquerque, Los Alamos, Colorado Springs, Kanata, Ottawa, and Guadalahara, Mexico.