5.9 Chemical Receiving, Storage, Spill Response & Hazardous Waste

Chemical Receiving, Storage, Spill Response & Hazardous Waste

The ABC Water Treatment Security, Safety, and Administrative Procedures area names "inspect, accept, and safely unload chemical containers," "use, handle, and dispose of chemicals according to the SDS," "respond to emergencies (e.g., facility upset, equipment failure, spill response...)," and "manage safety and environmental issues in compliance with appropriate regulatory agencies (e.g., Hazardous Waste Disposal and Air Quality Standards)."

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1. Hazard Communication and the Safety Data Sheet

OSHA's Hazard Communication Standard (29 CFR 1910.1200), aligned with the Globally Harmonized System (GHS), requires a written program, labeling, safety data sheets, and training. Virginia enforces it through VOSH.

The 16 SDS sections - know the numbers that matter

Signal words are precisely defined: "DANGER" for the more severe hazard categories and "WARNING" for the less severe. There are nine GHS pictograms, including the exclamation mark (irritant), skull and crossbones (acute toxicity), corrosion, flame, flame over circle (oxidizer), gas cylinder, health hazard, exploding bomb, and environment.

Secondary containers - a spray bottle, a bucket, a day tank - must be labeled with the product identifier and the hazard, unless the container is used by one employee within a single shift and remains in that employee's control.

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2. Receiving and Unloading

The delivery is the highest-risk chemical event at a water or wastewater plant, because it is the moment when a large volume of one chemical can enter the wrong tank.

The non-negotiable practices

1. Supervise every delivery. An operator meets the truck, verifies the product against the bill of lading and the tank label, and remains present through the transfer. Unattended deliveries are how hypochlorite ends up in the ferric tank.
2. Unique, keyed, labeled fill connections for every bulk chemical, so a hose physically cannot be connected to the wrong tank.
3. Verify tank capacity before transfer. Measure the level, calculate the available volume, and confirm the delivery quantity fits with freeboard.
4. Verify the product. Check the certificate of analysis and, for hypochlorite, verify strength on receipt rather than trusting the label - it degrades in transit.
5. PPE for the unloading operator per the SDS: at minimum chemical splash goggles and a face shield, chemical-resistant gloves and apron, and for gas or high-hazard products, respiratory protection immediately available.
6. Eyewash and safety shower within 10 seconds' travel, unobstructed, tested weekly and inspected annually.
7. Spill kit staged at the unloading point, with the correct absorbent and neutralizer for that chemical.
8. Vehicle restraint - wheel chocks and, where used, a fall-protection cage for top loading.

Incompatible chemical segregation

Store and pipe these so that a mistake cannot connect them:

Always add acid to water, never water to acid.

Secondary containment

Sized for the volume of the largest single tank plus freeboard for precipitation (commonly 110 percent of the largest tank). The containment coating must be compatible with the chemical, the containment must have no drain to a storm sewer, and any drain valve must be normally closed and locked. Accumulated rainwater must be inspected and tested before release.

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3. Chlorine and Ammonia Emergency Response

Chlorine facts an operator must know cold

• Greenish-yellow gas, pungent odor, detectable at around 0.3 ppm.
• Vapor density about 2.5 - heavier than air, so it settles into pits, trenches, and low areas.
• OSHA PEL: 1 ppm ceiling. NIOSH IDLH: 10 ppm.
• Liquid chlorine expands roughly 460 times on vaporizing.
• Never spray water on a chlorine leak. Water plus chlorine forms hydrochloric and hypochlorous acids that accelerate the corrosion of the container and enlarge the leak.
• Locate leaks with ammonia vapor from a squeeze bottle of about 10 percent aqueous ammonium hydroxide - a white cloud of ammonium chloride forms at the leak. Never spray liquid ammonia on the container.
• Chlorine Institute emergency kits: Kit A for 100 and 150 lb cylinders, Kit B for one-ton containers, Kit C for tank cars and tank trucks.
• Leaking cylinders should be positioned so the gas, not the liquid, escapes - keep the leak on the vapor side - which for a horizontal ton container means rotating the valves to the 12 and 6 o'clock positions with the leaking valve up.

Regulatory thresholds

A single one-ton chlorine container (2,000 lb) does not by itself reach the 2,500 lb RMP threshold, but two ton containers connected in a process do - and the quantity counted is the total in the process, not the amount in use. This is a common reason utilities converted from gas chlorine to sodium hypochlorite.

Sodium hypochlorite is not covered by RMP or PSM, which is a substantial part of its appeal, but it brings its own hazards: it is corrosive, it off-gasses, it decomposes, and it reacts violently with acid.

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4. Spill Response and Reporting

The response sequence

1. Protect people first. Evacuate or shelter, account for personnel, establish an upwind assembly point.
2. Identify the material from the label, SDS, or shipping papers - do not approach to read a label on an unknown release.
3. Assess - quantity, whether it is contained, whether it is reaching a drain or watercourse, and whether the responder is trained and equipped for that material.
4. Control the source only if it is safe and within training. A defensive action (closing a valve from outside the vapor cloud, damming a drain) is different from an offensive entry.
5. Contain - dike, absorb, or divert. Protect storm drains first; a chemical that reaches a storm drain becomes a surface water release.
6. Notify per the plan.
7. Clean up and dispose as a characterized waste.
8. Document and investigate.

Reporting obligations

Chlorine's CERCLA reportable quantity is 10 pounds - a small leak reaches it quickly.

Responder training levels (29 CFR 1910.120(q)): Awareness (recognize and notify), Operations (defensive containment from a distance - the level most plant operators hold), Technician (offensive, plug and patch), Specialist, and Incident Commander. Do not exceed your training level; the correct action at Awareness level is to withdraw and call.

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5. Hazardous Waste

Water and wastewater plants generate hazardous waste in small but real quantities: spent laboratory reagents, mercury from thermometers and UV lamps, spent solvents, lead-based paint from tank rehabilitation, expired chemicals, used oil, batteries, and cadmium waste from nitrate analysis.

The generator's obligations under RCRA (40 CFR 262)

1. Waste determination. Every waste stream must be evaluated for whether it is listed (F, K, P, or U lists) or exhibits a characteristic:
   • Ignitability - flashpoint below 140 degrees F;
   • Corrosivity - pH 2 or below, or 12.5 or above;
   • Reactivity - unstable, reacts violently with water, generates toxic gas;
   • Toxicity - fails the Toxicity Characteristic Leaching Procedure (TCLP) for any of 40 constituents.
2. Obtain an EPA identification number if required by generator category.
3. Generator category - Very Small Quantity Generator (100 kg or less per month), Small Quantity Generator (more than 100 kg up to 1,000 kg per month), or Large Quantity Generator (more than 1,000 kg per month, or more than 1 kg of acute hazardous waste). Accumulation time limits and requirements scale with the category.
4. Containers - in good condition, compatible, kept closed except when adding or removing waste, labeled "Hazardous Waste" with the contents and the accumulation start date, and inspected weekly.
5. Manifest - shipments move on a Uniform Hazardous Waste Manifest to a permitted treatment, storage, or disposal facility, with signed copies returned and retained three years.
6. Training and contingency plan appropriate to the generator category.

Universal waste and used oil

Many plant wastes are managed under the simpler universal waste rules: batteries, mercury-containing equipment, lamps (including UV disinfection lamps), and certain pesticides. Used oil has its own standards and is not automatically a hazardous waste if managed properly - but mixing used oil with a listed hazardous waste contaminates the whole volume, which is the single most expensive avoidable mistake in a plant maintenance shop.