August 2010, Vol. 22, No.8

Safety Corner

On Algae Cultivation

John W. Bannen

Across the country, wastewater treatment facilities are beginning to be looked at as a potential source for algae production in the quest for bioenergy. The ability to produce nonfossil fuels from aquatic biomasses grown as algae is being examined as being a mutually beneficial byproduct within the traditional wastewater treatment process. Because algae growth projects present unfamiliar operations and/or equipment, additional emphasis on safety during startup, maintenance, and other activities is essential.

For decades, operators have battled algae as nuisance organisms at some plants, while at others, algae are the primary source of treatment for the wastestream. But when ExxonMobil (Irving, Texas) begins predicting the possibility of 2000 gal of fuel per acre (18,700 L of fuel per hectare) of biomass, it creates a powerful incentive for finding suitable growing environments for the algae. The abundance of readily available water rich in nutrients, combined with available holding ponds, lagoons, or spare tanks, are making treatment facilities a prospective partner in producing biofuels.

The presence of algae poses no greater hazards or safety risks than plant operators are already exposed to, from a hygiene perspective. The hazards and risks of algae production in this new era of biomass pilot studies, projects, and experimentation lie within the work practices needed to grow and harvest the algae. The three main safety concerns for operators are the use of compressed gases, working above water, and biofuel operations. Even though working with gases and working above water are hazards that operators may be familiar with, the application to the new biomass production can create different risks.

Gas Cylinders
Carbon dioxide is used in the cultivation of algae as a source of carbon, food for the algae in the photosynthesis process. The feed of carbon dioxide from compressed-gas cylinders is used in most pilot and research project applications due to the lack of “flow-through” systems that would allow the use of naturally occurring carbon dioxide in the wastestream as the source of carbon for the algae, similar to the operation or a facultative lagoon or pond.

Multiple regulations address the safe handling, storage, and transportation of compressed-gas cylinders. U.S. Department of Transportation visual inspection criteria can be found in 49 CFR 171–179. Likewise, Safe Handling of Compressed Gasses in Containers (11th edition, CGA-P-1) from the Compressed Gas Association (Chantilly, Va.) details the standards for protection of employees exposed to the hazards of compressed-gas cylinders. The fifth edition of this text was incorporated into the U.S. Occupational Safety and Health Administration standard for the proper guidance for handling compressed-gas cylinders.

Because the material inside the compressed-gas cylinder is typically carbon dioxide, there are minimal hazards associated with the substance itself. Instead, the hazards lie in the handling, storage, and transport of the cylinders.

 

Working Above Water
The second hazard is one which all wastewater treatment operators should already be familiar with: working above water. Operators already must conduct sampling using catwalks or often have to take a position above the water to take a sample or perform maintenance in the plant. These activities will be replicated at the biomass growth area, and the risk could increase as the frequency of these activities increases for monitoring or other activities of the biomass project.

The federal standard 29 CFR 1926.106 states that “employees working over or near water, where the danger of drowning exists, shall be provided with U.S. Coast Guard-approved life jacket or buoyant work vests.” Additionally, there must be a ring buoy attached to at least 90 ft (27 m) of line located at intervals of no more than 200 ft (61 m).

Additionally, many plants already have and utilize a skiff when working on water, but many operators lack the proper training to be working directly above water from a small boat. The Coast Guard and safety-training companies can provide water-safety training, which will prepare employees for the associated hazards. Also, knowing the proper way to re-enter a boat after falling into the water, how to inspect a personal flotation device, and other basic water-safety skills should be communicated to all employees exposed to water hazards at the plant.

 

Biodiesel Production Facilities
While the U.S. Environmental Protection Agency (EPA) has released a guidance document titled Environmental Laws Applicable to Construction and Operation of Biodiesel Production Facilities (EPA-907-B-08-001), there is no specific, all-encompassing document related to employee safety in biodiesel production facilities, research projects, or pilot programs. The hazards of these situations must be evaluated and mitigated at each location by management at the facility.

As producing algae to make biofuel continues to gain momentum and production at wastewater treatment facilities increases, questions regarding environmental, operator, and public safety will come up and must be addressed fully. For example, will algae grown for biomass be subject to the Toxic Substances Control Act as a “modified organism”? Perhaps instead, EPA will declare algae a new class of biosolids to be used in biofuel production.

Each of these emerging issues, in conjunction with the hazards identified here, ensure that management, supervisors, and employees will have to address safety regarding this new technology with the same diligence and effort used to ensure safe work practices in today’s wastewater treatment plants.

 

John W. Bannen is the western region health and safety advisor in the Gilbert, Ariz., office of Severn Trent Services (Fort Washington, Pa.).

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