The Impact of Meat Production on The Environment Part 3

The Impact of Meat Production on

The Environment

Courtesy and Credit :

Mr.Prashant Parikh, Georgia Institute of Technology


Part 3

  • Environmental and Energy Analysis of Water Treatment

It has been reported by the California Energy Commission that water treatment plants are often the largest energy user of any government programs10. This is because the wastewater from food processing plants contains extraordinary high level of biochemical oxygen demand (BOD) and suspended solids (SS) not found in residential wastewater. In particular, these high levels of BOD and SS come from the blood and organs of the processed livestock. Generally, BOD and SS can be treated with large quantities of high quality water, however this process is inefficient and energy intensive. Air activated sludge (AAS) is one of the more common methods used to efficiently treat wastewater.

AAS serves multiple purposes that include oxidizing and removing biological matter, removing phosphate, and separating harmful gases such as carbon dioxide and ammonia2. The process involves the introduction of oxygen and microorganism into wastewater that contains of level of BOD. The goal is to provide the microorganisms, which are mainly comprised of bacteria and protozoan, a source of energy in order to grow and form biological floc1. As the biological floc forms, they consume the organic content of the wastewater and then precipitate into a sludge-like substance. Once the wastewater has been sufficiently treated, it is pumped to a settling tank where the floc precipitates to the bottom and then removed to landfills. The liquid wastewater is then pumped to more filtration chambers where it undergoes further treatment in order to remove any remaining microorganisms. This is often done by exposing the treated water to a high level of ultraviolet (UV) radiation through UV lamps. The UV disinfection in itself is a highly energy intensive process as it requires the water to be exposed to the UV radiation for an extended amount of time.

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Whether the treatment method is AAS or another, the treatment process requires a large amount of water and can be highly energy intensive. An independent research on ten water treatment plants done by SBW Consulting Incorporated outlines the amount of water and energy needed in the treatment of wastewater. The table below shows the ten plants involved in this research and the processed used by each.

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Though the size of each plant varies, the ten plants average 14.06 million gallon of water per day (MGD). The average energy usage for the treatment process, per pound of BOD removed, and per MG treated are 12907.6 kWh/d, 1.25 kWh/lb and 1231.3 kWh/MG respectively. The total electrical usage of nine of the ten treatment plants averages 34469.67 kWh/d or 2600 kWh/MG. Considering the typical cost of $0.10 per kWh, the plants cost on averages $3446.97 per day to treat water. This amounts to over $1.2 million a year.

Once the BOD and SS of the wastewater have been treated, ultraviolet radiation is then used to disinfect the partially treated water. The process, itself, is quite simple and much more efficient than the alternative of boiling the water. The treated water, and any bacteria present, is exposed to a large dose of UV radiation. The radiation damages the DNA and RNA of the bacteria which prevents it from reproducing, and thus disinfects the water10. Simple, however, does not always translate to energy friendly.

SBW Consulting Incorporated also did research on several plants that used UV disinfection and found an interesting result. The average energy used to disinfect one MG of water is 442 kWh. On a per day scale, the UV disinfection process accounted for 14% and 23% of the total energy used of two of the plants researched10. The table below shows the energy used by the plants researched.

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Since the treatment of water requires such large amounts of electricity to operate, the amount of indirect carbon dioxide (CO2) produced is highly significant. In the United States, more than half of the electricity generated comes from the combustion of fossil fuel with more than 94% of the total coal consumed in 2007 dedicated to electricity generation12. Since 1990,the increase in CO2 production has increased annually at a rate of 1.3%12. The increase in CO2 production for electricity generation alone is about 587.5 Tg. One of the primary factor that attribute to this growth is the overall growth in emissions from electricity generation due to economic growth11. The table below shows some of the primary sources of CO2.

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Since CO2 is one of the primary factors that impact the environment today, the amount of CO2 indirectly produced in the water treatment process is a topic of high interest. If the energy density of 6.67 kWh/kg of coal6 is considered, based on the average amount of energy of 34469.67 kWh/day for the ten treatment plants, the following is calculated:

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5167.87 kg of coal is used daily in the operation of the treatment plants. This amount can further be extrapolated to find the amount of CO2 produced by these plants. If the emission factor of coal is considered, 1 kg of coal produces 2.93 kg of CO26, the following is calculated:

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This can further be extrapolated to get an annual number of 5526.78 Mg CO2/year. Considering the total electrical production produces 2397.2 Tg of CO2, a single water treatment plant attribute 0.0002% of that CO2 production. In the state of Georgia, there are sixteen water treatment plants17. This means that Georgia alone is responsible for 0.0032% of the CO2 emission of water treatment.

CO2 production is not the only greenhouse gas produced during water treatment; methane (CH4) and nitrous oxide (N2O) also play a large role. Methane originates primarily from enteric fermentation associated with domestic livestock, decomposition of wastes in landfills, and natural gas, while nitrous oxide is emitted from agricultural soil management and mobile source fuel combustion12. During the water treatment process, CH4 is produced when the microorganisms break down waste and other organic material, and N2O is produced during the treatment process itself12. According to the Intergovernmental Panel on Climate Change (IPCC), methane is about twenty times as effective at retaining heat in the atmosphere than carbon dioxide. Since 1990, the total amount of CH4 and N2O in the atmosphere have decreased by 31.2 Tg CO2 Eq. (5.1%) 3.1 Tg CO2 Eq. (1.0%), respectively, however the amount emitted during the wastewater treatment process has increased by 1.7 Tg CO2 Eq (4.0%) and 1.2 Tg CO2 Eq. (30.7%)11. This increase in greenhouse gas during the treatment process also has a direct link to the growth of the economy. The two tables below shows the trends in CH4 and N2O emission for various sources.

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  •  Packaging of Beef:

Packaging is a crucial part of beef when it comes to production and selling of beef. Packaging of the beef takes place right after the slaughtering and cleaning of the beef. The main reasons for packaging is to protect against physical changes, against chemical changes, against microbes, and make the meat presentable to the people buying the meat(Patel .1). Packaging is basically the final product of beef before it is transported to the consumers. This is why packaging is so important.

Packaging of beef comes in different shapes and sizes. The packaging of the meat has to be able accommodate for the best shipping size and keep the meat fresh till it reaches its final destination with the consumer. The beef is stored at two point two degrees Celsius. The beef producers like to send the beef to the marked between twenty-four to forty-eight hours. The gas inside the refrigerator should be seventy percent carbon dioxide and the rest being nitrogen and oxygen. Majority of the time the meats like carcasses, sides, quarters, and primal cuts need to be delivered frozen. When the meats are frozen they either need to be bagged in paper bags and one stocknet, completely wrap in plastic with stockinet, or completely rap the meat in plastic or vacuum package and then box. This also adds to the energy cost because now the vehicles that transport the meats have to freezer capabilities. If the meat is fabricated bone-in and bones-in and boneless cuts, cuts, smoked and dried meats, and are not individually packed, then the container needs to be lined with plastic bags. Products may be individually wrapped or layer packed with waxed paper or plastic material that can be used for vacuuming or purposes like this. Here are some different types of packaging casing used:

Film Characteristics
Cellophane (100 grades) Printable, heat sealable, flexible oxygen impermeable.
Cellulose acetate O2 + Co2 permeable, oil resistant, not heat sealable used for fresh sausages.
High strength, oil resistant used for vacuum packages High strength,
oil resistant used for vacuum packages
LDPE derived ionomers Light + gas resistant, printable ,tough, easily laminated into retort pouches
O2 + H2O impermeable, very strong.
Metalized films
Nylon High temperature resistance, very impermeable to O2 + H2O ,
easily printable , tough.
Polybutylene terephahalate (PBT) Good heat, tear, abrasion, chemical resistance , needs adhesive to seal,
O2 + H2O impermeable . Used for retort pouches + laminates.
Polyester Oxygen permeabilty , easily sealed, moderate strength,
poor grease resistance, no heat resistance.
Polyethylene – HDPE, LOPE, LLDPE Stronger than PE, more heat resistant, more grease resistant
Polypropylene readily processed, clear, oxygen permeable , not resistant to flex.
Polystyrene very strong
Polyurethane very clear, heat stable and used as vacuum + heat shrink films.
Polyolefin Easily formed, easily sealed, strong, easily coated & printed.
Polyvinylchloride Extremely low H2O permeable, resistant to chemicals,
heat abrasion, tearing, oil & grease frequently used as a coating.
Polyvinylidine chloride with PP —– Saran

HariH Aum __/\__

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