Mounds require very diligent and careful construction practices. Mounds have been known to fail due to two main causes &#; too small of a basal area for the effluent flow from the house, and poor construction practices. To ensure a mound works as planned, construction practices must be followed very closely. Plus, the homeowner must use water wisely.
The first step in mound construction is to mow the grass or vegetative cover over the basal area to a maximum 2-inch height and remove all the cuttings. Then dig in the effluent line from the pumping station. The line must be installed below frost level or sloped uniformly back to the pumping chamber so it drains after the pump shuts off. The excavated trench must be backfilled and the soil firmly compacted to prevent effluent from flowing along the pipe.
Ground preparation comes next. The ground must be ripped or scarified with a chisel plow or the teeth from the backhoe bucket. Once the surface is prepared, no wheel traffic can be allowed in the basal area. Wheel traffic will seal the soil. Do not work in wet soil conditions because wet soil will compact, smear and seal the soil.
Next comes the fill sand. The fill sand should be washed and checked to be sure it contains no more than 10 percent fines. To test, put 2½ inches of sand in a quart jar and add water until about three-quarters full. Cover and shake to mix the sand and water. Let the mixture stand for an hour and measure the silt and clay accumulation on top of the sand. If the depth is ¼ inch or less, the sand is clean enough for use in the mound. This test should be done before the sand is delivered to the site. Pit run sand varies widely, even from the same area of a pit, and should not be used.
Place the clean sand starting at one end and work toward the other end. Drive on top of the sand as you progress. Shape the sand with a backhoe with tracks or a crawler tractor but make sure you have at least 6 inches of sand under the tracks. Wheeled vehicles should not be used for this operation. Do not allow the tracks to run directly on the earth. After forming with the tractor blade, level and do the final shaping by hand. The top of the sand bed should be level the full length of the mound.
For rock beds, a trench about 12 inches deep and 6 feet wide should be formed the required length on top of the sand. Place 6 inches of ¾- to 3-inch diameter rock in the trench. Place the pressure distribution pipe on the rock and cover with 2 inches of rock. Cover the rock with one of the following: a 4- to 6-inch layer of hay or straw, untreated building paper (red rosin paper) or a geotextile material designed for septic system drainfields.
For gravelless distribution, place the gravelless pipe or chamber on top of the level sand. Place the distribution pipe in the gravelless carriers and connect to the delivery pipe from the pump tank. Double-check all connections. Test the pump and distribution system before covering. Cover the gravelless system with a geotextile fabric and put a cap of heavy soil on top (Figure 24).
Cap the mound with a loam or loamy sand soil (Figures 23 and 24). Make the cap 12 inches high at the center of the bed and 6 inches high at the end of the bed. Taper the cap down the sides of the mound.
Last, cover the mound with 6 inches of good top soil and seed to grass. Don&#;t plant trees or shrubs on top of the mound. Water-tolerant shrubs may be planted around the base. Permanent lawn sprinkler systems should not be installed near enough to the mound to throw water on it.
Construct mounds to follow the contour of the existing ground. Never place a mound in a low area where water will accumulate. If the mound is on sloping ground, use a berm on the uphill side to divert runoff water around the mound. Mounds can be constructed to complement your landscaping design. Shrubs at the base of the mound will use water and help trap snow. If the mound is built in the fall, it should be covered with straw or hay the first winter to prevent freezing.
Working with wastewater and sewage presents many human health risks without the proper use of personal protective equipment (PPE). Wastewater workers encounter chemicals, bloodborne pathogens, viruses, and many more harmful substances while on the job and while performing typical work duties.
To protect your workforce and maintain in compliance with regulatory standards from entities as the Occupational Safety and Health Administration (OSHA), it is critical to understand what job hazards are present for sanitation and wastewater workers, how to mitigate these hazards, and what types of PPE are best suited for this environment.
Wastewater is used water and sewage. It contains substances including human waste, food scraps, oils, soaps, and chemicals.
Wastewater comes from both commercial and residential settings, including sinks, toilets, washing machines, dishwashers, and showers or bathtubs within private homes and businesses. Virtually every private citizen and industry&#;including agricultural, healthcare/medical, and construction&#;contributes to the estimated 18.7 trillion gallons of sewage produced every year in North America.
Storm runoff&#;water from rain and melting snow that runs off roofs, parking lots, roads, and sidewalks&#;is also considered a type of wastewater. Storm runoff can easily wash off harmful substances from these surfaces and flow into drains and waterways.
Because wastewater contains a broad range of contaminants and substances, much of this water must be cleaned or "treated" prior to being released back into the environment.
The wastewater treatment industry is part of the sanitation industry. The industry's primary aim is to remove as much of the suspended solids (effluent) as possible from used water before returning the water to the environment. Wastewater treatment plants can treat water up to different qualities or degrees in order to satisfy various industry-specific requirements.
In , the global water and wastewater market were valued at just over $263 billion, and is projected to reach a market value of nearly $500 billion by with a compound annual growth rate of 7.3 percent.
Wastewater treatment involves two main stages, primary treatment and secondary treatment. These treatments are sometimes combined into a single step. The primary treatment uses filtration processes to remove about 60 percent of suspended solids. During this stage, solids are allowed to settle (e.g., in sediment tanks) before being removed. Primary treatment also features aeration, which adds oxygen back into the water.
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Secondary treatment removes 85 to 90 percent of suspended solids. In this stage, biological processes, such as trickling filters and more commonly the activated sludge process, are used to enhance water purification.
Wastewater treatment is done to promote human and environmental health. Untreated wastewater can carry diseases, disrupt wildlife habitats, and expose humans, animals, and plant life to toxins, pollutants, excessive nutrients, and other harmful substances. Decaying organic matter also uses up dissolved oxygen found in water, and therefore can deprive fish and other aquatic lifeforms of the oxygen they need to survive.
According to the U.S. Centers for Disease Control and Prevention (CDC), the virus that causes COVID-19 has been found in untreated wastewater. However, "there is no information to date that anyone has become sick with COVID-19 because of exposure to wastewater." The CDC currently does not recommend any additional COVID-19 specific precautions for people working at wastewater treatment facilities, other than the standard PPE for sewage workers.
Sanitation and wastewater workers face some of the most dangerous occupational hazards in the country. The World Economic Forum ranks wastewater treatment plant operators as eighth in the list of ten most "unhealthy" jobs.
A wastewater worker's typical job duties include operating heavy machinery, working in confined and/or poorly ventilated spaces, and handling or transporting chemicals involved in water processing and treatment. All of these duties come with risks which may increase workers' risk of short- and long-term illness, injury, or even death due to factors such as:
These and other occupational hazards can lead to a range of injuries or illnesses, including:
According to the Bureau of Labor Statistics (BLS), safety trends are improving within the water and sewage industry, with 3 nonfatal injuries or illnesses reported per 100 workers in compared to more than 5 cases per 100 workers in . However, these rates continue to match or exceed the nonfatal illness and injury rates for all industries combined.
OSHA standards for wastewater practices are described in a variety of regulations, including 29 CFR for general industries, 29 CFR Subpart AA for confined spaces, and 29 CFR . for bloodborne pathogen standards (which pertain specifically to employees in wastewater treatment plants).
Wastewater treatment facilities who wish to remain in compliance with OSHA regulations must prepare written programs, provide ongoing worker training, conduct routine tests and audits, and (depending on company size) keep detailed records, among other practices.
Proper PPE for sanitation workers is essential for promoting wastewater treatment safety. All workers who handle sewage and are involved in water treatment processes must not only have the correct PPE at their disposal, but must also be properly trained in the donning, doffing, storage, and/or disposal of their PPE.
At a minimum, OSHA and the CDC advises the following PPE for sewage workers:
PPE used by sanitation workers should be intact and free of rips, tears, and other types of damage, and should also not impair a worker's dexterity or ability to perform his or her typical work duties.
In addition to proper PPE usage, the CDC also recommends additional general safety precautions for sanitation workers. For example, workers should be up to date on immunizations in accordance with local health guidelines (vaccine-preventable illness exposure may vary by location). Common immunizations recommended for sanitation workers include tetanus, Hepatitis A, and Hepatitis B.
Wastewater workers should be sufficiently and routinely trained on illness and injury mitigation protocols, including how to don and doff PPE, how to flush eyes after accidental exposure, and when and how to seek out medical attention following known or suspected exposure.
Finally, wastewater workers should be well-versed in general hygiene strategies, which include but are not limited to:
The wastewater industry is an integral component of public health and environmental protection strategies. BLS data suggests that workplace safety within this industry has improved in recent years. However, wastewater treatment remains one of the more dangerous jobs in the United States, resulting in both fatal and nonfatal injuries and illnesses every year.
To improve worker safety, reduce the risk of contamination, and protect local communities and the greater environment, all sanitation workers must have access to appropriate PPE at all times. Workers must be properly trained in how to use, don, and doff this PPE, maintain basic personal hygiene, and perform their job duties with great care. Employers within the wastewater industry must also do their part, by providing ongoing training and ensuring their company meets regulations set by local, state, and national authorities.
For the wellbeing of your staff&#;and the good standing of your company&#;it is essential to uphold best-practice OSHA standards for wastewater treatment plants. This starts with high-quality and cost-effective PPE. To explore PPE options for your sanitation or wastewater plant employees, contact International Enviroguard today or call us at 1-866-734-.
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