Vol. 6, No. 2 - June 1997

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North Carolina's Water Supply: A Case for Water Efficiency

Water supplies in many areas of North Carolina are in serious jeopardy. For example, underground water supply reservoirs in eastern North Carolina are dropping by as much as eight feet a year, land surfaces are settling as water is withdrawn, and the potential exists for salt water intrusion into underground drinking water supplies. In the Piedmont area, nearly all available supplies from surface water reservoirs are currently allocated to municipalities. And across North Carolina, the potential for water shortages is increasingly likely.

NC Usage

According to the University of North Carolina Water Resources Research Institute, approximately 4 million North Carolinians rely on groundwater (aquifers) for their daily water supply, and approximately 3.2 million rely on surface water (rivers and lakes). At an average daily consumption of 60 gallons per person, approximately 240 million gallons of groundwater and 192 million gallons of surface water are withdrawn daily for residential uses. The United States Geological Survey estimated that North Carolina industrial and commercial sectors used 332 million gallons per day from publicly supplied sources in 1995. In addition to these uses, the state's water balance also includes minimum quantities of water required to sustain aquatic life in our rivers and streams - of utmost importance to the state's fishing industry, tourism, recreation, and quality of life.

Local and State Response

In response to increased water supply demands and to extend raw water supplies and reduce potential drought periods that are beginning to plague North Carolina areas, several municipalities and water/sewer districts have implemented water efficiency programs. Table 1 lists substantial benefits that can be achieved through these programs.

Table 1. Benefits of Water Efficiency Programs

Reduced Water Demand:

Generally faster, easier, and less expensive than supply-side programs.

Water and Wastewater Treatment Savings:

Reduced costs and deferred plant expansion.

Less Environmental Impact:

Less surface and subsurface withdrawals and discharges.

Sustained Water Quality:

Reduced intrusion of groundwater contaminant and curtailed demand for new water supplies that are lower quality.

Water use rate structures can greatly influence efficiency efforts. Trends over the past 10 years show many municipalities moving away from traditional "declining block" rate structures in which the more water users consume, the less they pay. Alternative rate structures such as "uniform" and "inverted block" make efficiency measures more economically advantageous, although almost 52 percent of large municipalities still use declining block rate structures.

Coordinated Efficiency Efforts

Efficiency efforts need to be coordinated among the municipalities and districts that share a river basin and aquifers. North Carolina has been taking steps to improve the accountability and coordination of water use in the state. In 1989, the General Assembly passed a bill that addresses local and state water supply planning. Several bills and rules related to water management have been and are being passed. They include the reuse of reclaimed wastewater (FOCUS, Fall 1996), water supply watershed protection, the Water Use Act, the Coastal Area Management Act, and Basinwide Water Quality Planning.

This edition of FOCUS provides guidance and examples on the sound water efficiency practices businesses and industries can use to support the state's water management efforts.

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Water Efficiency: Sizing Up Your Facility

Water efficiency measures implemented by industrial and commercial facilities can be cost effective as well as environmentally sustainable. Some of the reasons to use water efficiently include preservation of quality water supplies; cost savings in water, sewer, chemical treatment, and energy; expansion of production without increased water use; and delay in the need for new water supplies.

In sizing up the efforts your facility is making in water efficiency, consider the following questions and suggestions for establishing a water efficiency program.

Top Management Commitment and Resources

  • Is water efficiency included in the company's environmental policy statement?
  • Are water efficiency responsibilities delegated?
  • Have quantitative goals been established, tracked, and communicated to employees?
  • Have incentives and feedback loops been established for employee participation and suggestions?
  • Have available resources been consulted (e.g., your utility company, federal, state, local assistance programs, vendors, or consultants)?

Water Efficiency Survey

  • Have water uses been defined (e.g. domestic uses, cooling and heating, process rinsing, landscaping, evaporation, leaks)?
  • Have life cycle water costs been determined for supply water, wastewater treatment, sewer/discharge, and heat and mechanical energy losses?
  • Have inspections been made for leaks, have unnecessary water uses been eliminated, and are timers used? (Tip: Listen for running water (i.e., leaks) when process is shut down.)

Identify Water Reduction Opportunities

  • Domestic: Fix leaks. Replace commodes with low-flush units or urinals. Install faucet aerators and low-flow shower heads.
  • Heating/Cooling: Eliminate once-through cooling water with chiller/cooling towers.
  • Process rinsing and cleaning: Implement countercurrent rinsing techniques. Install conductivity flow controls. Improve spray nozzles/pressure rinsing, fog rinsing, agitated rinsing (air blower, ultrasonics, pump circulation). Cut off water flows when not in use. Extend aqueous bath life via filtration and maintenance control. Use "dry clean-up" instead of hosing down. Use squeegees/brushes for pre-cleaning.
  • On-site Water Reuse: Match water use with water quality. Examine reuse applications for landscape irrigation, ornamental ponds, flush water, and cooling towers.
  • Landscaping: Install low-flow sprinklers or trickle/drip irrigation. Optimize watering schedules and water placement, preventative maintenance, and xeriscaping techniques.

Water Efficiency Action Plan

  • Has a cost analysis been conducted on water efficiency opportunities?
  • Is the implementation schedule prioritized?
  • Have water users been informed of changes, and have feedback channels been established and opened?

Tracking and Communicating Results

  • Have monthly water usage rates been posted for employees and management?
  • Has the water efficiency achievement been publicized through media coverage, mentoring to other businesses, business environmental exchange programs, or award programs?

For more information on water efficiency measures, contact the Division of Pollution Prevention and Environmental Assistance at (919) 715-6500.

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Water Efficiency: Cooling Towers

It is not uncommon for cooling towers to consume 20 to 30 percent of the water supplied to commercial and industrial facilities. Water savings can be achieved by reducing blowdown or water discharges from cooling towers. Consider the following water-saving suggestions:

The table below outlines advantages and disadvantages of options to optimize cooling tower operations.




Operational Improvements

  • Low capital cost.
  • Low operating cost.
  • Low maintenance requirements.
  • Limited cycles of concentration.

Sulfuric acid treatment

  • Low capital cost.
  • Low operating cost.
  • High cycles of concentration possible.
  • Possible safety hazard.
  • Possible damage to system if overdosed.

Sidestream filtration

  • Reduced possibility of fouling.
  • Higher operating efficiency.
  • Reduced maintenance.
  • Reduced bleed-off.
  • Moderately high initial capital cost.
  • Limited effectiveness for solids removal.
  • Additional energy costs for pumping.

Ozonation system

  • High cycles of concentration possible.
  • Eliminates chemical treatment.
  • High capital investment.
  • Complex system.
  • Additional energy costs.
  • Possible health hazards.

Reuse of water within facility

  • Reduces overall facility water consumption.
  • Possible requirements for pretreatment (additional chemical and energy costs).
  • Increased potential for fouling if poor quality water used.

Source: Water Management: A Comprehensive Approach for Facility Managers. Enviro-Management & Research, Inc.

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Water Resources on the Internet . . .

Other Resources on the Internet . . .

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One Water Utility's Approach . . .

In response to increased demand and limited water resources, the Regional Water Authority of Asheville, Buncombe, and Henderson (formerly ABWA) instituted an aggressive water efficiency program in 1991. Some of the program's initiatives include rebates to replace older commodes with low-flow units; free retrofit kits that include faucet aerators, a low-flow shower head, and a toilet tank displacement bag; and literature and a video to encourage water conservation by homeowners and small businesses.

In addition, ABWA contracted with the Waste Reduction and Technology Transfer (WRATT) Program, which is administered by the Land-of-Sky Regional Council, to conduct water reduction assessments at no charge for a range of customers. The WRATT Program relies on retired engineers and scientists to conduct technical assistance services, including water reduction assessments. For the 90 assessments conducted, WRATT recommendations resulted in water consumption savings of more than 300 million gallons per year and corresponding cost savings of more than $300,000 per year.

Jim Stokoe, WRATT Program Director at (704) 251-6622, can provide assistance with a water or multimedia waste reduction assessment in western North Carolina; and Jennifer Ball at (704) 259-5958 can provide more information on the Authority's water efficiency initiatives.

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Efficiencies in Facility Domestic Water Use Offer Cost Savings Potential

Often overlooked at commercial and industrial (C/I) facilities is domestic water use and the potential for significant cost savings through efficiency. Water efficiency measures should begin with the highest water use operations such as cooling, cleaning, rinsing, heating.

Easy improvements in domestic water fixtures such as commodes, faucets, and showers are often overlooked. The quantity of domestic water use at C/I facilities may range from a small percentage at a food processing industry to over 50 percent in an office setting (Figure 1).
Average daily domestic demands in C/I settings range between 20 and 35 gallons per day (gpd) per employee, but savings of 25 to 30 percent are readily achievable.
A facility's assessment of domestic water use should start with the location and repair of any leaks. Pressures in the fixtures also should be checked. A leaky toilet can waste more than 50 gpd; a dripping faucet can waste 75 to 1,000 gallons per week. Outdated fixtures should be evaluated. Faucet aerators and low-flow showerheads will provide payback in less than 3 and 6 months, respectively.
Replacing a 3.5-gpf toilet with a moderately priced 1.6-gpf unit will provide a payback of 1.5 to 3.5 years (Figure 2).

Based on a commercial water and sewer rate of $3.97/1000 gallons and 3 flushes per employee per shift.

Table 1 lists sound water efficiency choices for domestic fixtures.

Table 1. Application Guidance for Domestic Water Efficiency


Current Style/ Flow Rates

Typical Ages

Water Efficiency Options/Cost estimates



Flushometer(Flush valve) 3.5 gpf Pre-1980's to early 1990's
  • Install 1.6 gpf repair/retrofit valve ($25-35) and change china fixture ($115-$300).
Must change both bowl and valve.


Flushometer 4.5 gpf Pre- 1980's
  • Install 3.5 gpf repair/retrofit valve ($25-35) with no change to china bowl.
  • Consider valve inserts to save 0.5 gpf ($10.00).
Flushometer valves used in commercial, high use areas.


Tanks-type/gravity 1.6 gpf 1992 and later Best available option Ultra-low flush (<1.6 gpf) for special enviro-sensitive cases.


Tanks-type/gravity 3.5 gpf 1980 to mid-1990
  • Install 1.6 gravity flush ($115-300) Install 1.6 gpf pressurized tank style unit ($275-$450). Displacement devises/dams not typically recommended for 3.5 gpf units
Must replace commodes to further reduce flow. Pressurized tank styles recommended for high use areas.


Tanks-type/gravity 5 - 7 gpf Pre-1980
  • Consider dams, displacement, or early closure devices (<$20).
  • Install 1.6 gravity flush ($115-$300)
Do not use bricks. Consider pressurized tanks systems for high use areas.


Flushometer 1.6 gpf --
  • Install repair valves to 1.0 or 0.5 gpf ($25-35).
For non-pooling models.


Flushometer 3.0 gpf --
  • Replace urinals fixture and repair valves to 1.0 gpf ($125-$300)


2.5 gpm Post mid-1990's
  • Currently best option: lower-flow showerheads available (down to 1.5 gpm) for special conditions.
Rated at 60 psi pressure.


3 - 5 gpm Post 1980
  • Install 2.5 gpm showerhead (<$20).
Appropriate pressure needed.


5 - 8 gpm Pre-1980
  • Install 2.5 gpm showerhead (<$20).
Appropriate pressure needed.

Kitchen Faucets

3 - 7 gpm Pre-mid 1990
  • Install aerators to reduce flow to 2.5 gpm ($5-10 installed).
No less than 2.5 gpm should be used in kitchen applications.

Lavatory Faucets

3 - 7 gpm Pre-mid 1990
  • Install aerators to reduce flow to 2.5 to 0.5 gpm ($5-10 installed).
Can go down to 0.5 gpm for bathroom wetting services
* Cost estimates are based on approximate installed cost using internal maintenance. Actual cost may vary. Options are based on widely available equipment believed not to reduce service quality or reliability.

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Landscape Irrigation

Consider the following ideas to reduce the amount of water required for landscape irrigation.

The following are among the many benefits xeriscape landscaping provides:

Source: Water Management: A Comprehensive Approach for Facility Managers. Enviro-Management & Research, Inc.

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Water Efficiency Case Studies

Safelite Glass Company, Enfield, NC

Safelite Glass manufactures windshields for the automotive industry. In order to reduce or eliminate its monitoring requirements and compliance concerns associated with its NPDES direct wastewater discharge permit, Safelite evaluated its operations and identified several major sources of wastewater. The major sources included three water-cooled air compressors, cooling water for the autoclave and hydraulic fluid, and rinse waters for the glass cutting process. As a result of this evaluation, the facility implemented the following projects.

Safelite Glass Company Wastewater Reduction Techniques

Wastewater Reduction Technique


Annual tap and sewer water savings (million gallons)

Replaced two water-cooled air compressors with two electric air cooled compressors



Close-looped the autoclave cooling water



Utilized cooling water from third air compressor and hydraulic fluid cooling water for boiler make-up water



Installed mist nozzles for application of rinse water underneath glass



Installed triggering device on top rinse to shut off flow between glass sheets



Total Wastewater Reduction


The volume of wastewater now discharged is less than the EPA threshold that requires pollutant analysis. Although some of these activities required a high capital cost, the elimination of monitoring requirements and compliance concerns and reductions in tap water fees provided Safelite the incentive to implement the projects.

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Craftsman Fabrics Industries, Inc., Concord, NC

Craftsman Fabrics dyes or bleaches and then finishes cloth for knit goods manufacturers. Like many textile dyehouses, Craftsman used to dye various loads with the same volume of water and chemicals, regardless of the size. Although formulating dyebaths was easy with this method, more chemicals and water were often used than were required to properly process the fabric. To reduce water and chemical consumption and wastewater pollutants, Craftsman implemented the following modifications to the dyehouse operation:

Craftsman now uses less water and fewer chemicals per pound of fabric by varying the fill levels according to the machine used, size of load, and type of fabric. Thus, for an approximate capital cost of $42,000, Craftsman now saves annually approximately $170,000 in reduced water and chemical costs and increased production output. The company has also reduced wastewater use by an estimated 14 million gallons and chemical use by 0.9 million pounds annually.

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Multimedia News Update

Water Quality News

Mass-Based Limits

While water conservation provides many benefits, a successful program can have a negative effect on wastewater compliance. Because the amount of dilution water is decreased, water conservation will increase the concentration of pollutants in the wastewater for facilities with concentration-based permit limits, mg/L. Thus, a facility may be out of compliance under the concentration-based limit although the facility is discharging the same mass of pollutants, lbs/day.

One effective solution to the problem is to implement a chemical conservation program or other reduction techniques for those chemicals that end up in the wastewater. A second solution is to work with the local water authority to switch concentration-based limits, mg/L, to mass based limits, lbs/day. Many companies have already successfully switched their limits to mass-based.

To determine the mass of pollutants discharged in the wastewater, the facility will need an effluent flow meter to record the daily wastewater flow. The flow, along with the effluent analysis, is used to determine the actual pounds of pollutant discharged. Although there is a capital investment for the flow meter, the cost of the meter is typically paid back quickly in reduced sewer fees for facilities with evaporative losses.

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Air Quality News

Division Initiates Ozone Action Days

Ground-level ozone, the major component of smog, is produced primarily from industrial activities and gasoline burning vehicles. Ground-level ozone is harmful to humans, especially the young, elderly, and individuals with respiratory illnesses. Urban and surrounding areas that are heavily industrialized and populated typically have the highest ozone concentrations and are the most regulated.

With the potential onset of more stringent air quality standards for ozone, the North Carolina Division of Air Quality (DAQ) has recently created the NC Air Awareness Program. The education and outreach components of the program will inform the general public, business/industry, and school children about air pollution, its causes and effects and prevention techniques. When the potential exists for the ozone standards to be exceeded, DAQ will announce Ozone Action Days through newspapers, television, radio, and local employers. To help reduce the number of vehicles driven on those days, DAQ encourages car pooling, telecommuting, and eating in at lunch time, whenever possible. For further information on NC Air Awareness, call 1-888-RU4NCAIR.

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Solid Waste News

Recycled Materials Replace Virgin Materials

North Carolina industries use an impressive variety of recycled feedstock - from common post-consumer materials such as paper fiber to post-industrial materials such as chemicals and textiles. Manufacturers may choose to incorporate recycled materials into their processes because of cost savings, locally available raw materials, the environmental benefits, and customer demand. In a recent survey of North Carolina plastic manufacturers conducted by the NC Recycling Business Assistance Center (RBAC), 91 percent of the respondents cited cost savings in raw material purchases as a major reason the company uses recycled feedstock. And although the survey identified quality concerns as a barrier to the use of recycled feedstock, some companies reported that recycled feedstock improves their product quality.

North Carolina companies should evaluate their feedstock use to determine if opportunities exist to incorporate recycled material into their processes and if such a change could improve their competitiveness. For additional information on this topic, contact the RBAC at (919) 715-6500.

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Hazardous Waste News

Management of Oil Absorbents

The NC Division of Waste Management policy bans absorbents containing oil from North Carolina solid waste landfills. However, the Division does not ban absorbents used to clean up incidental spills of petroleum products such as small volume leaks or spills at service stations, auto dealers, and garages that can be readily cleaned up. Larger volumes of absorbents should be handled through waste oil dealers or hazardous waste service companies.

Here are tips to prevent or reduce the generation of waste absorbents:

One company that provides an oil absorbent mat or sock rental service picks up the used mats and extracts the oil at its plant. The mats are then laundered and reused.

Contact the Hazardous Waste Section at (919) 733-2178 or the DPPEA at (919) 715-6500 for more information on absorbent management or alternatives.

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Compliance Tips for Small Businesses

Air Emissions Inventory Due June 30, 1997

All air permit holders are required to report their "1996 North Carolina Air Emissions Inventory" to the applicable regional Air Quality Office by June 30, 1997. Pollutants subject to the reporting are the criteria pollutants, North Carolina toxic air pollutants, and federal hazardous air pollutants as listed in the 1990 Clean Air Act Amendments.

To obtain an accurate emissions figure, look at processes, products, and quality of products used over the last year, as well as Material Safety Data Sheets. The Division of Air Quality has spreadsheets for a number of processes (e.g., sawmills, boilers, furnaces) and can assist with locating emission factors, if needed.

If you need assistance or have questions, contact your regional air quality staff or the Office of the Small Business Ombudsman at 1-800-829-4841. This Office provides free, confidential, technical environmental assistance to small businesses.

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Calendar of Events



Date (1997)


Process Solutions Recovery & Recycle Info Exchange Arlington, VA June 17-18 Kathy Noll, CTC
ACEEE Summer Study on Energy Efficiency in Industry Saratoga Springs, NY July 8-11 Debbie Giallombardo, ACEEE,
Engineering Solutions to Indoor Air Quality Problems Raleigh, NC July 21-23 Air & Waste Mgmt. Assn.,
U.S. Dept. of Energy 13th Annual Pollution Prevention Conference: Spotlighting Success Atlanta, GA August 26-28 Conference Information Hotline:
888-660-P213 or
Small Quantity Hazardous Waste Generator Courses NC: Wilmington, Raleigh, Winston-Salem, Mooresville August -TBA Linda Culpepper, Hazardous Waste Section,
919-733-2178, ext. 216
Southern States Annual Environmental Conference. Biloxi, MS September 23-25 Mississippi State University - MISSTAP

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The North Carolina Division of Pollution Prevention and Environmental Assistance provides free, non-regulatory technical assistance and training to eliminate, reduce, or recycle wastes before they become pollutants or require disposal. For additional information about any of your waste reduction concerns, contact DPPEA at (919) 715-6500 or 800-763-0136 or e-mail nowaste@p2pays.org.

DPPEA-97-30. June 1997