Biochemical Oxygen Demand of Food Waste SciFair Projects

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RESEARCH REPORT

Introduction
Humans have a need for water, and not only water, but also water that is clean. Biochemical Oxygen Demand is a measure of the oxygen needed for all of the organisms in a body of water to live. If there is an over population in microorganisms, the microorganisms take more of the oxygen than allowed for them, ventually smothering the larger organisms such as the fish.

Rivers

Water pollution
Water pollution occurs when a body is aversely affected due to the addition of large amounts of materials to the water. The sources of water pollution are categorized as being a point source or a non-source point of pollution. Point sources of pollution occur when the polluting substance is emitted directly into the waterway. A pipe spewing toxic chemicals directly into a river is an example. A non-point source occurs when there is runoff of pollutants into a waterway, for instance when fertilizer from a field is carried into a stream by surface runoff.

Types of Water Pollution
Toxic Substance -- A toxic substance is a chemical pollutant that is not a naturally occurring substance in aquatic ecosystems. The greatest contributors to toxic pollution are herbicides, pesticides and industrial compounds.

Organic Substance -- Organic pollution occurs when an excess of organic matter, such as manure or sewage, enters the water. When organic matter increases in a pond, the number of decomposers will increase. These decomposers grow rapidly and use a great deal of oxygen during their growth. This leads to a depletion of oxygen as the decomposition process occurs. A lack of oxygen can kill aquatic organisms. As the aquatic organisms die, decomposers break them down, which leads to further depletion of the oxygen levels.

A type of organic pollution can occur when inorganic pollutants such as nitrogen and phosphates accumulate in aquatic ecosystems. High levels of these nutrients cause an overgrowth of plants and algae. As the plants and algae die, they become organic material in the water. The enormous decay of this plant matter, in turn, lowers the oxygen level. The process of rapid plant growth followed by increased activity by decomposers and a depletion of the oxygen level is called eutrophication.

Thermal Pollution -- Thermal pollution can occur when water is used as a coolant near a power or industrial plant and then is returned to the aquatic environment at a higher temperature than it was originally. Thermal pollution can lead to a decrease in the dissolved oxygen level in the water while also increasing the biological demand of aquatic organisms for oxygen.

Ecological Pollution -- Ecological pollution takes place when chemical pollution, organic pollution or thermal pollution is caused by nature rather than by human activity. An example of ecological pollution would be an increased rate of siltation of a waterway after a landslide, which would increase the amount of sediments in runoff water. Another example would be when a large animal, such as a deer, drowns in a flood and a large amount of organic material is added to the water as a result. Major geological events such as a volcano eruption might also be sources of ecological pollution.

Specific Sources of Water Pollution
Farming:

Farms often use large amounts of herbicides and pesticides, both of which are toxic pollutants. These substances are particularly dangerous to life in rivers, streams and lakes, where toxic substances can build up over a period of time.
Farms also frequently use large amounts of chemical fertilizers that are washed into the waterways and damage the water supply and the life within it. Fertilizers can increase the amounts of nitrates and phosphates in the water, which can lead to the process of eutrophication.
Allowing livestock to graze near water sources often results in organic waste products being washed into the waterways. This sudden introduction of organic material increases the amount of nitrogen in the water, and can also lead to eutrophication.
Four hundred million tons of soils are carried by the Mississippi River to the Gulf of Mexico each year. A great deal of this siltation is due to runoff from the exposed soil of agricultural fields. Excessive amounts of sediment in waterways can block sunlight, preventing aquatic plants from photosynthesizing, and can suffocate fish by clogging their gills.

Business:

Clearing of land can lead to erosion of soil into the river.
Waste and sewage generated by industry can get into the water supply, introducing large organic pollutants into the ecosystem.
Many industrial and power plants use rivers, streams and lakes to dispose of waste heat. The resulting hot water can cause thermal pollution. Thermal pollution can have a disastrous effect on life in an aquatic ecosystem as temperature increases the amount of oxygen in the water decrease, thereby reducing the number of animals that can survive there.
Water can become contaminated with toxic or radioactive materials from industry, abandoned hazardous waste sites and mine sites.
Acid precipitation is caused when the burning of fossil fuels emits sulfur dioxide into the atmosphere. The sulfur dioxide reacts with the water in the atmosphere, creating rainfall, which contains sulfuric acid. As acid precipitation falls into lakes, streams and ponds it can lower the overall pH of the waterway, killing vital plant life, thereby affecting the whole food chain. It can also leach heavy metals from the soil into the water, killing fish and other aquatic organisms. Because of this, air pollution is potentially one of the most threatening forms of pollution to aquatic ecosystems.

Homes:

Sewage generated by houses or runoff from septic tanks into nearby waterways, introduce organic pollutants that can cause eutrophication.
Fertilizers, herbicides and pesticides used for lawn care can runoff and contaminate the waterway. As with agricultural fertilizers, home fertilizers can lead to the eutrophication of lakes and rivers.
Improper disposal of hazardous chemicals down the drain introduce toxic materials into to the ecosystem, contaminating the water supplies in a way that can harm aquatic organisms.
Leaks of oil and antifreeze from a car on a driveway can be washed off by the rain into nearby waterways, polluting it.

Wastewater Treatment
We consider wastewater treatment as a water use because it is so interconnected with the other uses of water. Much of the water used by homes, industries, and businesses must be treated before it is released back to the environment. If the term "wastewater treatment" is confusing to you, you might think of it as "sewage treatment." Nature has an amazing ability to cope with small amounts of water wastes and pollution, but it would be overwhelmed if we didn't treat the billions of gallons of wastewater and sewage produced every day before releasing it back to the environment. Treatment plants reduce pollutants in wastewater to a level nature can handle.

Wastewater is used water. It includes substances such as human waste, food scraps, oils, soaps and chemicals. In homes, this includes water from sinks, showers, bathtubs, toilets, washing machines and dishwashers. Businesses and industries also contribute their share of used water that must be cleaned.

Industrial Waste systems
Most sewer systems, wastewater treatment and disposal systems are designed primarily to treat domestic wastewater. However, many businesses and industries generate industrial wastewater, which must be disposed of in a cost effective and environmentally responsible manner. This is where industrial waste system comes in. Unauthorized discharges of industrial wastes have the potential to damage our rivers. To ensure that these environmental and public health controls are maintained, the Industrial Waste service incorporates a 'Permit' system to manage the industrial waste systems. Each business is individually assessed when they connect to the service, and any pre-treatment requirements or other necessary controls on the wastewater discharges from their activity are specified in the 'conditions' associated with their Permit. The businesses must submit a BOD, and 15 other requirements are required every month.

BOD
Biochemical oxygen demand is measure of how much dissolved oxygen is being consumed as microbes break down organic matter. A high demand, therefore, can indicate that levels of dissolved oxygen are falling, with potentially dangerous consequences for the river's biodiversity.

High biochemical oxygen demand can be caused by high levels of pollution, caused usually by poorly treated wastewater or by high nitrate levels, which can also trigger plant growth. Both result in higher amounts of organic matter in the river. When this matter decays, the microbiological activity uses up the oxygen. Biochemical oxygen demand is therefore one of the main parameters used in the Urban Wastewater Treatment Directive for controlling discharges. Unsurprisingly, large rivers, where wastewater plants are more likely to be located, registered higher levels of oxygen demand than smaller rivers. Improvements in wastewater management saw biochemical oxygen demand fall in all sizes of river during the early 1990s. However, levels have begun increasing slightly more recently in all but the small rivers. Overall, the 2000s saw a drop in biochemical oxygen demand, indicating relatively well-oxygenated rivers across the U.S. There is, however, a significant difference between northern and southern states.

Chemical Oxygen Demand
COD is used as a measurement of pollutants in natural and waste waters, to assess the strength of discharged waste such as sewage and industrial effluent waters. It is normally measured in both municipal and industrial wastewater treatment plants and gives an indication of the efficiency of the treatment process. COD is measured in both influent and effluent water (before and after treatment). The efficiency of the treatment process is normally expressed as COD Removal, measured as a percentage of the organic matter removed during the cycle of treatment.

pH
pH is a measure of the degree of the acidity or alkalinity of a solution as measured on a scale (pH scale) of 0 to 14. The midpoint of 7.0 on the pH scale represents neutrality, i.e., a "neutral" solution is neither acid nor alkaline. Numbers below 7.0 indicate acidity; numbers greater than 7.0 indicate alkalinity. It is important to understand that pH is a measure of intensity, and not capacity; i.e., pH indicates the intensity of alkalinity in the same way temperature tells how hot something is - but not how much heat the substance carries

Tree Top's wastewater Treatment method
Tree Top's Wastewater treatment facilities, use microorganisms to clean their wastewater. Tree Top stores the water in large pools with irritation motors giving the water more oxygen so the microbes are able to clean the water. Once the water is cleaned it flows in a third pool with only two irritation motors to keep the microorganisms alive until it is drained out into the spray fields which gets sprayed into a field near the river and eventually makes it's way through the ground water into the Yakima River.

Summary
The wastewater treatments are, as you can see, one of the most important aspects of our environmental welfare. The BOD is an important aspect of wastewater treatment; it is a requirement of the EPA. Clean water is not only needed by humans but by all living organisms. So you can understand why this is an important process.

ACKNOWLEDGEMENTS

I would like to thank the following people for helping make my project possible:

My mom for driving me to the spray fields, and getting me in touch with Carol
Carol for helping me perform my project
Mr. Newkirk for guiding me to my finished project
Mrs. Helms for all the little things that help make this project one of a kind.