Water Treatment Process example essay topic

Water Pollution: Is it as big of a problem as we think? The following essay will be looking at the factors that cause pollution, and the effect that pollution has on our world today. It will also investigate what it has in store for the future if things do not improve. It will also explore some of the methods used to treat and clean-up wastewater, and oil spills. Today, the industrialization of Canada is severely affecting this nation slakes, streams, and rivers. If something is not done to improve the situation it is going to have some severe environmental problems in its future.

Today pollution is very high in both inland and marine waters. All different types of water pollution are contributing factors in this problem. Here are some things that are associated with pollution: Pathogens: Pathogens are disease causing bacteria, viruses, and protozoa. They usually come from human sewage. As pathogen numbers increase, so does the risk of human health. Biochemical Oxygen Demand: Organic wastes that decay in a body of water. decrease the amount of oxygen found in it.

The living things in the lake need oxygen to survive. If the oxygen level is depressed to zero, all fish in the lake die. Any decomposition that does not contain oxygen starts to generate noxious gases such as Hydrogen Sulfide. Pulp and paper mills, and municipal sewage causes BOD. Nutrients: Nutrients, particularly nitrogen and phosphorus, enrich waters and accelerate the aging of lakes and streams. Also, the result of this is rich plant life which prohibits recreational activities.

Plankton blooms depress oxygen levels (as mentioned before) and therefore, endanger living organisms. Major sources of nutrients are municipal sewage and agricultural runoff. Toxic Materials: Can affect the health of aquatic organisms and their consumers, and the people who drink the contaminated water. The toxicants include lead, mercury, DDT, PCB, , oil, and.

These chemicals enter the lake through dumping by the factories. Temperature Changes: Temperature changes from waste heat discharges (like from a nuclear power plant) can cause pollution. This happens if their elevation reduces dissolved-oxygen levels, and accelerates eutrophication, which in turn affects the ecological processes and blocks the migration path of fishes. Acidification: Acidification (acid rain etc.) Is caused by sulfur and nitrogen oxide in the rain, which is caused by automobiles and large industries. Temperature Changes: The temperature of a body of water is changed by waste heat discharges, like that of a nuclear power plant. It affects ecological processes and blocks the migration paths of fish.

Because of these pollutants Southern Saskatchewan and Alberta are threatened by water shortages, and the great lakes face problems in serious pollution. Rivers and streams are also greatly affected by these pollutants. The noticeable outcomes of these pollutants are these: Nitrates in drinking water can cause disease in infants that may sometimes end in death. Crops in a field can absorb sludge-derived fertilizer, and when humans eat the crop it may result in acute liver and kidney damage. Sometimes lakes become artificially enriched with nutrients from the chemical fertilizers that run off cultivated fields into the water.

This causes water that is unpleasant to drink due to bad odor, taste, and algae. Also, acid rain has left many lakes in Canada totally devoid of life. There are three major sources of water pollution, they are municipal, industrial and agricultural. Municipal: This type of water pollution comes from the wastewater found only in homes and commercial establishments For many years people have been placing importance on treating the waste to remove harmful bacteria, etc. from it. Recently we are coming aware of the fact that we have to improve the ways in which we dispose of the waste. Industrial: Industrial waste is wastewater from industrial areas, and companies.

There are many different types of chemicals, and they all have different affects. Some are not as severe as others, but all are harmful. They vary due to the amount they contain of specific substances. Agricultural: Agricultural waste is a form of pollution that is the source of many organic and inorganic pollutants in waters in the ground and on the surface.

Wastes from commercial feeders, animal wastes, chemicals, etc. Run of into the land through leaching and runoff. What is the typical wastewater from these categories made up of? Wastes from toilets, sinks, industrial processes, and agricultural chemicals and leftovers.

Treatment of such sewage's as these is required before it may be buried, reused, or sent back into the water system safely. In a treatment plant, the polluted water is passed through a series of chambers, screens, and chemical processes to reduce its bulk and toxic level severity. There are three general steps to water treatment. They are usually classified as being part of primary, secondary, or tertiary treatment. Primary Treatment: During this level, a large percentage of the suspended solids and in organic material is removed from the sewage waste. Secondary Treatment: The focus of secondary treatment is to reduce the organic material content.

They do this by accelerating the natural biological processes. Tertiary Treatment: This group of treatment is necessary when the water will be reused. At this time 99% of the solids in the water are removed and various chemical processes are used to ensure the water is as free from as many impurities as possible. After the water treatment process has been broken into three categories, it can be further broken down into a number of smaller headings. Here is a summary of some of the steps: Grit Chamber: The wastewater that enters a treatment plant contains debris that might clog or damage the pumps and machinery. So the sewage is passed through the grit chamber.

These are long, and narrow settling tanks, that is used to remove such inorganic, and mineral matter such as sand, silt, gravel, and cinders. They made all particles 0.2 mm or larger to settle at the bottom. Sedimentation Tank: When grit is removed, it passes into the sedimentation tank. In this step all organic materials settle on the bottom, and are drawn off for disposal.

This procedure can remove about 20 to 40 percent of BOD 5 and 40 to 60 percent of suspended solids Digester: This is a complicated step. The object of it is to make the chemically complex organic sludge to methane, carbon dioxide, and an inoffensive humus type material. First the matter is made soluble by enzymes, then the substance is fermented by a group of acid-producing bacteria, reducing it to simple organic acids such as acetic acid. The organic acids are than converted to methane and carbon dioxide by bacteria. Thickened sludge is heated and added as continuously as possible to the digester, where it remains for 10 to 30 days and is decomposed. Digestion reduces organic matter by 45 to 60 percent.

Drying Beds: Digested sludge is placed on sand beds for air drying. Percolation into the sand and air drying are the main processes involved in the de watering process. Air drying requires dry, relatively warm weather for greatest efficiency, and some treatment plants have a greenhouse-like structure to shelter the sand beds. Dried sludge is used in most cases as a soil conditioner; sometimes it is used as a soil fertilizer because of its two percent nitrogen and 1 percent phosphorous content. Trickling Filter: In this process, a waste stream is distributed intermittently over a bed or column. A gelatinous film of microorganisms coats the bed, and functions as the removal agent.

The organic matter in the waste stream is absorbed by the microbial film and converted to aerobic products. The reduction of the amount of BOD 5 is about 85 percent. Activated Sludge: This a process where the sludge particles are suspended in an aeration tank and supplied with oxygen. The organic matter is absorbed by the activated sludge particles and converted to aerobic products.

The reduction of BOD 5 fluctuates between 60 and 85 percent. There are a few other remaining steps but they are pretty straightforward, such as disposing of the waste. Sometimes the sewage is not cleaned or treated and is dumped directly intothe river. This results in lakes and rivers that look very brown and dirty not clean and clear. The pollution of rivers and streams with chemical contaminants has become among the most critical environmental problems of the century. It is estimated that 10 million people die each year from drinking contaminated water!

Another big problem are Oil spills. These large scale accidental discharges of liquid petroleum products are an important factor of the pollution along shorelines. The most spectacular spills involve the supertankers that are used to transport the product, but offshore drilling contribute to a large share of the pollution. One estimate is that for every million ton of oil that is shipped, one ton is spilled. Some of the largest spills recorded are from the tanker Amoco Cadiz off the French coast in 1978 (1.6 million barrels of crude oil). The Ix toc I oil well in the gulf of Mexico in 1979 (3.3 million barrels).

The largest spill in the US (240,000 barrels) was that of the tanker Exxon Valdez in Prince William Sound, Gulf of Alaska, in march 1989. Within a week, under high winds, this spill had become a 6700-sq. -km., slick that endangered wildlife and fisheries in the entire gulf area. The oil spills in the Persian Gulf in 1983, during the Iran-Iraq conflict, and in 1991, during the Persian Gulf War, resulted in enormous damage to the entire area, especially to the marine life. One of the methods used to clean up oil spills is a long sponge that they drag along the surface of the water that soaks up all the oil.

It is a long and tedious job, but it works quite well. if you would like to see them you could look back on FIG 1-2. The wastes treated are the ones that flow into the sewer system and enters the treatment plant. But some wastes are discharged directly into the Marine Waters. In fact, in the U.S. it is estimated that 45 million metric tons of sewage each year ends up in the marine waters.

About 80 percent of this amount of waste is produced by dredging, 10 percent is industrial waste, and 9 percent is sewage sludge. The U.S. alone produces 4,036,300,000 metric tons of sewage per YEAR! The following elements combined have very serious consequences: The presence of toxic substances, the rapid uptake of contaminants by marine organisms, heavy deposits of materials on the seabed near the shore, and the excessive growth of undesirable organisms. A person living in a wealthy, industrialized nation may produce as much a 875 kg (more than 1900 ponds!) of garbage per year! that means that by the time they are seventy years old they will have produced 61250 kg!

(133000 pounds!) These numbers are pretty scary, especially when multiplied by millions to find out the whole country's kilograms per year. The average person needs to pay attention to the amount of waste they produce, and try to cut back a little. But what exactly needs to be improved? Well, domestic, or household waste includes a wide variety of items, But it is often a mix of potentially reusable or recyclable items, (such as newspaper and cans. ), and largely non-recyclable material (such as broken, worn out devices, and plastic wrappings).

Due to dwindling space for landfills, many cities have adopted widespread recycling programs in which people separate the recyclable things apart from the non-recyclable garbage. And the recyclable goes to a recycling plant to be reused, and the remaining garbage goes to a landfill. What is the composition of wastewater, and how do we discover it? Well, the composition is what it is made up of as in, how many parts of water does it have and what the parts are made up of. To find out scientists analyze it.

This is done by using several physical, chemical, and biological measurements. The most common analyses include the measurements of solids, biochemical oxygen demand (BOD 5) chemical oxygen demand (COD), and pH. the solid wastes include dissolved and suspended solids. the suspended solids are further divided into settle able solids. All of THESE solids can be divided into volatile or fixed solids being inorganic or mineral matter. The concentration of organic matter is measured by the BOD 5 or COD analyses. to see a typical chart of the breakdown, concentration, and composition. After the water is treated where does it Go? Most often a direct discharge into a receiving lake or stream is the answer.

But in some areas of the United States that are faced with worsening shortages of water for both domestic and industrial use, some places are turning to reuse of appropriately treated wastewater for groundwater recharge, irrigation of non edible crops, industrial processing, recreation, and other uses. Where does the wastewater originate from? Mainly form domestic, industrial, groundwater, and meteorological sources. And these are most commonly known as Domestic Sewage, Industrial Waste, Infiltration, and Storm-Water Drainage.

Domestic Sewage: This type of wastewater results from peoples day to day activities, such as bathing, body elimination, food preparation, and recreation, averaging about 227 liters (about 60 gallons) per person per day! Industrial Wastewater: The quantity and character of industrial wastewater is highly varied, depending on the type of industry, the management of it's water usage, and the amount of treatment the water receives before it is discharged. But to give you an idea of the amount I have a figure for a steel mill. One steel mill may discharge anywhere from 5,700 to 151,000 liters (about 1,500 to 40,000 gallons) per ton of steel manufactured. A typical metropolitan area discharges a volume of wastewater equal to about 60 to 80 percent of its total daily requirements! The rest is being used for washing cars, watering lawns, and for manufacturing processes such as food canning and bottling.

Infiltration: This occurs when sewer lines are placed below the water table or when rainfall goes down through the earth to the pipe. We do not like it because it means that the piping system and the treatment plant have to work extra hard Storm Water Drainage: This is simply the water from rain, melted snow, etc. draining into our pipelines and sewers where it goes to a treatment plant to be treated, but there is nothing wrong with it. In conclusion, From all the points I have brought up it is easy to see that the more people there are in the world the more water pollution there is going to be. That doesn't mean that we have to stop having children, what it means is that we have to start watching where we drain our polluted water, and start to use our resources more wisely.

We should also be more careful with hazardous chemicals, and things like oil drilling, etc..