Factsheet: Waste Management and Minimization for Bluelining and Electrostatic Plotting

Board of Public Works
HTM Office
City of Los Angeles

Hazardous & Toxic Materials Office
Board of Public Works
City Hall
200 N. Spring Street, Room 353
Los Angeles, California 90012
(213) 237-1209

Rev. 3/95

Bluelining

Background

Bluelining (blueprinting or whiteprinting), the process of making blueprint drawings, is performed widely in many engineering, architectural, mapping, and graphics departments throughout the Los Angeles area. Bluelining is popular due to its relatively low operating and per print costs. Blueline prints are also preferred for field use due to their durability and reduced glare compared to other types of prints. A main concern with the bluelining process is its use of ammonia and the production of ammonia vapors and waste ammonia solution.

Process Description

The bluelining process occurs in two distinct steps. In the first step, the translucent original drawing is placed over the blueline paper (paper coated with diazo salts) and fed through the machine where it is exposed to an ultraviolet (UV) light that turns the exposed parts of the paper white. In the second step, the original is removed and the copy is re-fed into the developer chamber where the unexposed paper reacts with ammonia vapor and turns blue.

There are two main types of blueline machines, anhydrous ammonia machines and aqueous ammonium hydroxide machines. Anhydrous machines are used in printing shops for large volume reproduction applications. In anhydrous machines, dry ammonia gas flows from high pressure storage tanks to the developer chamber. Since the paper requires a humid environment for reaction, distilled water is also pumped into the chamber and heated to 150o - 180o F. A vent is usually used to collect and remove the ammonia vapor to a control device.

Aqueous ammonium hydroxide machines are more commonly used for low volume jobs, especially for engineering or architectural applications. The machines use one gallon bottles of aqueous ammonium hydroxide (aqua ammonia) to generate ammonia vapor. The bottle is connected to the machine with two or three plastic hoses. One hose bubbles air into the liquid to drive the ammonia gas out of solution, another hose pumps the vapor from the bottle to the developer tank. A third hose may be used to return the ammonia vapor to the bottle.

On most aqueous ammonia machines, there is no separate power control for the pump. Ammonia vapor is pumped into the developer as long as the machine is running. On some machines, the pump speed can be adjusted to a high or low level. The low level allows the pump flow to recirculate in the top (vapor area) of the ammonia jug and is used for normal operation when the ammonia is reasonably fresh or when only a small number of prints are being run. In the high position, air is bubbled into the ammonia to drive off the maximum amount of vapor. The high position is used when the ammonia is old and weak or when running large prints at rapid speed.

A filter device is usually attached to aqueous ammonia machines to collect the ammonia exhaust. The filter may be in the form of a cartridge that fits into the machine, or an external carbon adsorption canister that is attached to the exhaust. The canister may contain citric acid, sulfuric acid, or phosphoric acid to neutralize the ammonia.

Waste Management

The wastes generated by both types of bluelining machines include ammonia vapors, spent filters, burned-out lamps, and paper that is aged, moist or wrinkled. With aqueous ammonia machines, generation of weak ammonia water is a sizeable waste stream. Waste management techniques for each type of waste are given below:

• Ammonia vapors: Blueline machines are designed to emit less than 10 ppm ammonia to the workplace area. This is below the OSHA PEL (Permissible Exposure Limit, eight hour time-weight average) of 25 ppm. The ammonia can be a nuisance but is not considered hazardous under normal operation.

• Spent filters: The charcoal vapor collection canisters or filters must be changed when they become saturated, usually after two bottles of ammonia are consumed. An exhausted canister may contain concentrated phosphoric or citric acid salts. Consult the manufacturer of the filter for disposal guidelines. It may be possible to seal them in a plastic bag and disposed of with normal office trash. Recyclable vapor filters are now available from Planet Protection Systems.

• Burned-out lamps: Fluorescent Blue Diazo (UV) lamps may be a RCRA Hazardous Waste and must be disposed of accordingly. Check with the local Department of Toxic Substances Control office for further information. Mercury vapor lamps, used in some anhydrous machines, can be recycled or rebuilt by the manufacturer.

• Waste Diazo Paper: Old or waste diazo paper can be disposed of with normal office trash.

• Waste aqueous ammonia: Under normal use blueline machines typically generate one to four gallons of waste aqueous ammonia per month. The ammonia bottle must be changed when the solution drops to between 16o and 18o Baume. Ammonium hydroxide solution of this concentration will not generate sufficient ammonia vapor for the developing step. New aqueous ammonia is 26o Baume (29.5% ammonia by weight).

Flushing ammonia down the drain is not recommended because the Los Angeles City maximum pH for sewer disposal is 11. Typical pH of spent ammonia is between pH 11 and 12. Disposal of ammonia down the sewer may also require a permit. Also, unless extremely dilute, the ammonia is potentially toxic to marine life.

Neutralization with acid to bring the pH down to 7 may be dangerous if done by untrained personnel. Neutralization with hydrochloric acid will produce copious fumes of ammonium chloride and requires protective equipment. Neutralization may also require a permit to treat hazardous waste.

Reusing waste ammonia as a household cleaner or garden fertilizer is questionable because the strength and purity of the ammonia may be unknown. Commercial household ammonia contains 5 to 10% ammonia by weight whereas spent ammonia may contain 15 to 25% ammonia which may cause burns or irritation to the eyes and upper respiratory tract.

The best disposal technique for waste ammonia is to recycle it. State law now requires generators of hazardous waste attempt to recycle their waste before disposal. Most suppliers will pick up small quantities of used ammonia and recycle it or have it recycled by an ammonia recycler. However, most suppliers charge a fee for this service. Most will not pick up large quantities of stockpiled waste ammonia; an ammonia recycler such as Pacific Diazo should be contacted directly for disposal options. The California Waste Exchange is another source of information on ammonia recycling. New ammonia should be purchased from vendors who agree to pick up the used ammonia and recycle it or have it recycled by a recycling firm.

Waste Minimization Techniques

There are several ways to reduce bluelining wastes:

• Proper storage and monitoring of fresh ammonia: The strength of new or fresh ammonia should be at least 24o Baume, preferably 26o. Fresh ammonia may be supplied weak. Generally, if one gallon of ammonia in a case is weak, the rest of the case may be assumed to be weak and the entire case should be returned to the vendor for replacement.

  A Baume meter (a hydrometer used to measure the specific gravity of a solution) can be used to check the strength of "new" ammonia. This technique will limit the waste associated with disposing of "new" ammonia suspected of being weak. However, since specific gravity is not an exact measure of the vapor-producing strength of ammonia, this method is limited to testing new ammonia and not for determining replacement time.

  In general, ammonia needs to be replaced for every 3,000 square feet of paper developed, but this figure varies by machine and frequency of use. This corresponds to replacement once every one or two months for average operations. In practice, ammonia should be changed whenever the prints turn out faded or green in color.

• Use of full strength ammonia: 26o Baume rather than 24o Baume ammonia should always be used when replacing spent ammonia. The 24o Baume solutions are designed for machines with variable speed pumps. Perfumed or lemon scented ammonia should be avoided because it is generally supplied weaker than 26o Baume solutions.

• Perform regular servicing and maintenance: Regular servicing of a blueline machine will reduce ammonia usage since leaks in the developer tank seals and gaskets are a common cause of ammonia vapor loss. Blurred prints can be avoided by replacing broken or loose drive belts.

• Proper operation of equipment: Blueline machines tend to malfunction when they are operated incorrectly. "Helping" prints through the printer by pulling on the print or original causes double imaging. Also, if the copy is not kept flat and slid firmly into the developer, it will tend to wrinkle. Wrinkled and blurred prints have to be redone. This leads to the production of waste paper and more ammonia usage.

  If the blueline machine has an adjustable pump speed, the pump should be kept in the low (normal) position to conserve ammonia. The pump should be switched to the high position only as the ammonia becomes weak and nears replacement, or as the job requires. Carefully heating the ammonia bottle with a blanket heater as it weakens may extend the useful life of the solution.

• Proper storage of blueline paper: Blueline paper should be stored in a dry, dark area to avoid the collection of moisture and exposure to light. This practice will help minimize the production of wrinkled prints caused by use of photochemically degraded or moisture saturated paper.

• Use of an ammonia-free system: Ammonia-based blueline machines can be replaced with newer ammonia-free Pressure Diazo (PD) machines that use a clear, petroleum-based liquid developer instead of ammonia. However, print quality is not as good or as consistent as ammonia machines. Also, service and repair costs tend to be about twice as high as ammonia machines.

• Use of plotters: Blueline machines can be replaced with electrostatic, thermal, or pen plotters. However, plotters are more expensive and produce waste streams of used toner, pens, and thermal paper. They also need to be interfaced with expensive Computer Aided Drafting (CAD) hardware and software.

Electrostatic Plotting

Background

Bluelining is rapidly losing popularity to electrostatic plotting for the production of blueprints and drawings. Electrostatic plotters have many advantages over bluelining: they can interface directly with CAD machines to make multiple, high quality prints without the use of noxious chemicals. The CAD operator can also manipulate drawing dimensions and paper size. However, electrostatic machines have the disadvantage of having much higher capital and per-print costs than blueline machines. Electrostatic plotters also produce a waste stream of used and residual toner.

Process Description

There are two main types of electrostatic machines, dry toner copiers (i.e. Xerox machines) and wet toner plotters (e.g. Calcomp plotters). The dry toner machines used for engineering graphics are simply large scale versions of ordinary office copiers designed to handle and reproduce large, D size (30.5" X 42") blueprints. Dry toner machines can duplicate, reduce, and enlarge original drawings or blueprint copies. Wet toner plotters are designed to interface with CAD systems to make direct printouts of computer-based drawings. Their primary use is to make a hard (paper) copy of the computer image. They are not designed for duplicating or reducing and enlarging original prints. Typical engineering facilities that produce drawings and graphics use both wet toner plotters for hard copy CAD printouts and dry toner copiers for duplicating wet toner prints and blueline machine prints.

Dry toner is a fine powder composed of resin, pigments, and minor quantities of functional additives depending on the specific machine and manufacturer. Electrostatic plotters use a wet toner and replenisher rather than a dry toner. Wet toner is composed of 90% aliphatic hydrocarbons, 3% carbon black, and 7% copolymer. The toner is prepared by mixing separate clear and black solutions to create a suspension of particles. The optical density of the toner is monitored by a sensor. Since the toner tends to physically settle and chemically deteriorate over time, replenisher, a concentrated form of toner, is automatically added in small amounts to the toner solution to maintain an optimum optical density. Shaking or agitating the toner containers may extend the use of the toner by resuspending toner pigment.

Waste Management

Dry toner copiers produce a waste stream of dry waste toner that is collected in plastic recovery vessels within the copier.

Electrostatic plotters produce two waste streams. One stream is the residual toner that is left in the empty plastic toner container. The second waste stream is the unused toner which undergoes both chemical and physical changes as it sits in the plotter. Eventually, the toner's density becomes too low and it must be drained from the plotter and replaced (approximately every 3-6 months), regardless of how much toner is left unused. Waste management techniques for both types of toner are discussed below.

• Dry Toner: Left-over toner is classified as a non-hazardous waste by toner producers (e.g. Xerox, Cannon, Ricoh). It is not recyclable. The entire dry toner collection vessel should be placed in a plastic bag and disposed of with normal office refuse.

• Wet Toner: Spent wet toner is classified as a characteristic hazardous waste due to its ignitability. A waste recycler/hauler that specializes in small quantities of spent hydrocarbons should be contracted for disposal of waste toner. Any residual or unused toner should be drained into a suitable container supplied by the contractor. Once empty, the toner container is exempt from regulations as a hazardous waste and can be thrown out with normal office waste. A container is defined as empty if no waste or residual toner can be poured or drained when the container is tilted or inverted in any direction (22 CCR). The waste toner is picked up by the contractor and blended with other hydrocarbons for use as a fuel. A better solution is to explore a recycling option with the toner/plotter vendor.

Waste Minimization Techniques

Methods for reducing the waste associated with electrostatic plotters that generate waste toner include:

• Frequent use of electrostatic plotters: The best waste minimization method for wet toner is to use the plotter frequently enough to avoid the generation of off-specification waste toner. This would require a plan to centralize plotters to maximize their use and maintenance. Plotters that are rarely used should be eliminated.

• Replacement with thermal or pen plotters: Electrostatic plotters can be replaced with pen or thermal paper plotters. While eliminating waste toner, this option would generate empty pens and waste thermal paper. Furthermore, thermal plots tend to fade and deteriorate faster than electrostatic plots and pen plotters cannot produce as detailed of drawings as electrostatic plotters.

Resources and References

The following section contains a list of manufacturers, vendors, and government agencies that were contacted to provide information for this report. It also serves as a resource guide for the further research of disposal options, recycling, new products, and regulatory guidelines on the disposal of waste ammonia and liquid toner. The following are listed for information only, no endorsement is expressed or implied.

Technical Assistance for this publication provided by Jacobs Engineering Group

Plotter and Photocopier Manufacturers

Xerox Product Safety (800) 828-6571

CalComp Material Safety Dept. (714) 821-2000

Blueline Vandors and Service

Klingler (Manufacturer of blueline paper) (310) 512-6444	Oce-Bruning (Manuf. of PD machines) 10349 Heritage Park Drive, Suite 3 Santa Fe Springs, CA 90670 (310) 946-6636
Repro-Graphic Supply (Sales and service of blueline machines) 10537 Glenoaks Blvd. Pacoima, CA 91331 (818) 890-2663	Pacific Diazo Products (Suppliers and recyclers of ammonia, Baumemeters, adsorption canisters) 333 E. 157th Street Gardena, CA 90248 (310) 324-6799
Architects and Engineers (Suppliers of blueline paper) (818) 357-9691	Perfect Circle Technologies (Authorized dealer for Planet Protection Systems) (310) 515-0115

Government Agencies

CAL EPA Department of Toxic Substance Control, Region 3 Glendale, CA (818) 551-2800	California Waste Exchange Department of Toxic Substance Control 400 P Street, P.O. Box 806 Sacramento, CA 95812-0806 (916) 322-3670
Cal/OSHA 455 Golden Gate Avenue, Room 5246 San Francisco, CA 94102 (415) 703-4050	Cal/OSHA Consultation Services 10350 Heritage Park Drive, Suite 201 Santa Fe Springs, CA 90670 (310) 944-9366
City of Los Angeles Bureau of Sanitation (213) 485-5886	City of Los Angeles Board of Public Works Hazardous and Toxic Materials Office 200 N. Spring Street, Room 353 Los Angeles, CA 90012 (213) 237-1209