17-2 Hazard Analysis

Principal unique hazards associated with ultraviolet oxidation include:

a. Physical Hazards

(1) Description: Certain components of UV treatment systems, such as the UV lamps and the ozone generator, may generate heated surfaces which may cause burns to unprotected skin.

Control: These heated surfaces may be insulated or cooled either by ventilation or through a heat exchanger. Insulated gloves may be worn to prevent heat thermal burns. CONTROL POINT: Design, Operations, Maintenance

(2) Description: UV oxidation systems utilize high-voltage mercury lamps which may operate on voltages up to 3,000 volts. Breakage of the lamps may cause electrocution.

Control: Verify that the hazardous area classifications, as defined in NFPA 70-500-1 through 500-10, are indicated on the drawings. All controls, wiring, and equipment should be in conformance with the requirements of EM 385-1-1, Section 11.G or NFPA 70 for the identified hazard areas. High-voltage components should be provided with ground-fault protection if required by EM 385 1-1, Section 11 or NFPA 70 requirements. Cover panels of the UV lamps should be equipped with interlocks that ensure the system is de-energized when doors are opened. CONTROL POINT: Design, Construction, Operations, Maintenance

(3) Description: Although hydrogen peroxide solutions (27-52%) are not combustible, as strong oxidizers they can greatly intensify combustion. They also present an explosion hazard because of violent decomposition when heated or contaminated with oxidizable materials including iron, copper, brass, bronze, copper, and other metals (see Material Safety Data Sheets for complete listing). Contact with reducing agents, or organic and combustible materials (wood, paper) may cause immediate spontaneous ignition.

Control: A plant-specific lock-out/tag-out program designed after the requirements of 29 CFR 1910.147 should be implemented for maintenance procedures. Plant operators should become familiar with the reactive properties of hydrogen peroxide through a plant-specific hazard communication program designed in compliance with the requirements of 29 CFR 1910.1200. Store hydrogen peroxide solutions in their original containers in a cool, clean, fire-resistant area away from combustible materials, catalytic metals, direct sunlight, and other potential sources of heat and/or ignition. Maintaining the purity of the solution is important. Do not return unused material to its storage container after removal. All equipment that may contact hydrogen peroxide solutions should be selected, designed, and maintained to minimize the reactive hazards of these materials. It is recommended that the storage location have secondary containment. An ample source of water must be readily available for handling spills. CONTROL POINT: Design, Operations, Maintenance

(4) Description: UV oxidation facilities may contain vaults and vessels which require entry as a normal part of operation and maintenance. These spaces have the potential to contain hazardous atmospheres, and/or engulfment dangers due to the nature of materials and equipment used in the treatment process.

Control: Designers should, where possible, eliminate confined space in the design. If confined spaces can not be eliminated, designers should seek to minimize maintenance requirements in these spaces. Despite efforts to reduce the number of confined spaces which require entry, treatment plants will, out of operational necessity, have confined spaces. Dangers posed by confined space which require entry are best controlled by plant personnel following a plant-specific confined-space entry program designed after the requirements specified in the Occupational Safety and Health Administration=s (OSHA's) confined-space standard in 29 CFR 1910.146. Designers should ensure that liquid oxygen storage vessels and distribution systems comply with the requirements specified in NFPA 50 and 29 CFR 1910.104. Plant operators should become familiar with the hazardous properties of liquid oxygen through a plant-specific hazard communication program designed in compliance with the requirements of 29 CFR 1910.1200. CONTROL POINT: Design, Operations, Maintenance

(5) Description: Operation of UV oxidation systems can generate gases and build pressure in the process units. There is a hazard for the workers for an explosion and release of the reagents and contaminated materials. Some UV/oxidation systems use liquid oxygen to generate ozone. Liquid oxygen storage creates the potential for fire and explosion.

Control: Designers should include pressure-relief valves and vents discharged away from the work area. Alarm systems and monitors to detect pressure build-up, emergency release systems for head spaces, and emergency plans for operations should also be considered. CONTROL POINT: Design, Operations, Maintenance

(6) Description: Permanent or semi-permanent treatment buildings may present life safety hazards such as inadequate egress, fire suppression systems, and/or emergency lighting systems.

Control: Permanent and semi-permanent treatment system buildings should be constructed in accordance with ANSI 58.1: Minimum Design Loads for Buildings and Other Structures; the National Fire Code; the National Standard Plumbing Code; Life Safety Code; and the Uniform Building Code. Depending on where the project is located, the structures must also comply with the Air Force Manuals on Air Force bases, the USACE Technical Manuals on Army installations, or Local Building Codes on Superfund, BRAC, or FUDS project sites. CONTROL POINT: Design, Operations

(7) Description: The operation of a UV-based treatment system utilizes lamps that emit UV radiation that may cause eye damage.

Control: Workers should minimize their exposure to the UV light by wearing the appropriate ANSI-approved eye protection, utilizing the appropriate shade. CONTROL POINT: Operations, Maintenance

(8) Description: Noise hazards may be associated with the use of an air compressor to generate ozone.

Control: Isolated generator rooms should be included in the design and a hearing protection policy should be developed in accordance with 29 CFR 1910.95. CONTROL POINT: Design, Operations, Maintenance

(9) Description: Emergency shower/eye wash equipment required per 19 CFR 1910.151 is not always provided with adequate floor drains, thereby creating potential electrical hazards or walking surface hazards during required testing/use.

Control: Showers/eye wash equipment should be equipped with accompanying functional drains to isolate and collect the shower/eye wash water from unprotected electrical equipment and walking surfaces that, when wet, create slipping hazards. CONTROL POINT: Design

b. Chemical Hazards

(1) Description: Workers may be exposed to mercury if mercury-vapor-filled lamps are damaged or broken during installation, inspection, or replacement. Mercury overexposure may cause various symptoms including damage to the central nervous system, conjunctivitis, and inflammation to the nose and throat.

Control: Mercury lamps should be handled with caution to help prevent breakage, and mercury spills should be immediately removed. Mercury spill kits should be available in the immediate work areas. CONTROL POINT: Construction, Operations, Maintenance

(2) Description: Ozone may be produced via an on-site ozonator to enhance the performance of UV oxidation systems. Ozone may leak through seals or pipe junctions, or ozone levels may increase in the work environment if the ozonator fouls. Ozone is a potential experimental tumorigen and teratogen. Exposure to ozone may irritate exposed skin. Depending upon the degree of exposure, ozone may cause irritation of the eyes and respiratory tract, diminished lung function, pain or difficulty breathing, chest tightness, coughing, wheezing, increased sensitivity of the lungs to allergens and bronchoconstrictors, and increased susceptibility to lung-based bacterial and viral infections.

Control: Ozone may be removed by local or general ventilation of the work area. The UV chambers should have closed tops and controlled vents. Gas-tight covers may be required on sumps and holding tanks downstream of ozone generation systems. The vessels should be passively ventilated or actively ventilated through ozone decomposition equipment to the outside of the building. Equipment should be interlocked with ozone generation equipment and set to shut ozone generation off if plant levels exceed the ACGIH TLV for ozone. Monitors should set off alarms to warn treatment plant operators if plant levels exceed the ACGIH STEL. A plant-specific hazard communication program should address the symptoms of ozone exposure and procedures to reduce exposures to acceptable levels. CONTROL POINT: Design, Operations, Maintenance

(3) Description: Worker inhalation/ingestion/dermal exposure may occur during the use of catalysts (compounds which lower energy required for a chemical reaction to occur) that may be used in the treatment of waste materials in conjunction with UV oxidation. In addition, workers may be exposed to acids and bases which may be used in the process to control pH levels.

Control: Catalysts used in this treatment process may act as sensitizers, and all contact should be minimized. Workers should wear personal protective equipment and clothing (e.g. an air-purifying respirator with HEPA(N100, R100, P100) filters, chemically-resistant disposable coveralls, and protective gloves (e.g. nitrile)), as appropriate, based on the materials to be handled. CONTROL POINT: Design, Operations, Maintenance

(4) Description: Hydrogen peroxide may also be used to help improve the efficiency of UV oxidation systems. Hydrogen peroxide is an oxidizer that may react violently with organic materials either in the waste stream or in other materials, causing fire or system over-pressurization. Exposure to hydrogen peroxide may cause irritation or chemical burns to the skin and damage eyes. Dermal or eye contact with, or inhalation of, the splatters or mists of hydrogen peroxide solutions pose a hazard to personnel due to chemical burns associated with acute exposure.

Control: Secondary containment is required for storage of hydrogen peroxide. Whenever possible, hydrogen peroxide solutions should be automatically fed into the treatment system. If manual addition of the solutions is required, protective clothing will be necessary. Gloves made of natural rubber or nitrile offer good chemical resistance to solutions of 30-70% hydrogen peroxide. Leather and many fabrics, including cotton, rayon, and wool, should not be worn when handling hydrogen peroxide solutions because they present a fire hazard if they become contaminated with hydrogen peroxide. It is recommended that garments of polyester-acrylic (anti-static treated) fiber be worn when handling hydrogen peroxide solutions. Splash-proof chemical safety goggles and face-shields should also be worn. Control mists with local ventilation or by respiratory protection, as determined by a qualified health and safety professional. CONTROL POINT: Design, Operations, Maintenance

(5) Description: Workers may be exposed to pH control agents (acids and bases) during operations.

Control: The secondary containment storage areas for acids and bases should be constructed of materials compatible with storage of these materials and clearly marked. Acids and bases should be stored in separate areas. Emergency showers and eye wash stations that comply with 29 CFR 1910.151(c), and the design requirements specified in ANSI Z358,1 (1990), should be located near the reagent storage areas. Handling of pH agents should be automated to the extent practical. An emergency plan should be prepared and facility personnel should be trained to safely handle acids and bases. Manual handling of acids and bases should be done by personnel familiar with their properties and equipped with personal protective equipment (PPE), such as leather or rubber acid-resistant boots, chemical-resistant coveralls, goggles and face shields, air-purifying respirators (as indicated by the reagent), and rubber or other acid and base resistant gloves (e.g. nitrile) or gauntlets. CONTROL POINT: Design, Operations, Maintenance

c. Radiological Hazards

Description: The mercury lamps used in the treatment generate high levels of UV radiation. Typically the UV is contained within the treatment unit. However, radiation that is released may damage eyes or increase the risk of skin cancer.

Control: To protect personnel from radiation exposure, the reactor vessel must be equipped with interlocks that de-energize the system when the door is opened. Viewing ports in reactor walls may be equipped with glass covers that prevent transmission of UV radiation. CONTROL POINT: Design, Operation, Maintenance

d. Biological Hazards

Description: NONAPPLICABLE

Control: NONAPPLICABLE