Effects on the World

Man has had many far-reaching effects on the environment over the years. Global

warming, pollution and the damage to the ozone layer are a few of the major things that can be

heard about in the news. Man has damaged the earth gradually over the years and this damage

cannot be reversed, we are now trying to stop any more damage being caused to the

environment. For example, hedgerows have been destroyed but now people have realized what

effects this is having on the environment the government are paying farmers to replant them

instead of fencing. Not all of man's effects on the environment are harmful some are beneficial.

Conservation work is going on across the country and this is helping to preserve the wildlife and

countryside that we have left. The expanding human population has placed a huge demand on

the food production of the country. The resources are limited but the population is increasing

quite rapidly so the problems are growing. The demand for food means that crops need to be

perfect so the use of fertilizers and herbicides is increasing too.

One of the problems in the countryside affecting the environment is the disposal of

effluent and other pollutants. The main type of waste that we have to dispose of is organic

effluent particularly from farms and sewage works. This is disposed of in several ways, the main

one being pumping it into the sea and rivers around the country. In more recent years sewage

recycling plants have been developed to reuse the water in the waste. Water treatment works are

used to treat the waste before it is pumped into the river or sea.

The disposal of the waste is accomplished in several ways. Direct removal into a stream

or lake is the most commonly used means of disposal. In parts of the world that are faced with

worsening shortages of water for both domestic and industrial use, authorities are reusing

appropriately treated wastewater for, irrigation of non-edible crops, industrial processing,

recreation, and other uses. In one such project, the Potable Reuse Demonstration Plant in

Denver, Colorado, the treatment process uses normal primary and secondary treatment followed

by lime clarification to remove suspended organic compounds. During this process, an alkaline

state is created to improve the process. In the next step, re-carbonation is used to bring the pH

level to neutral. Then the water is filtered through several layers of sand and charcoal, and

ammonia is removed by ionization. Pesticides and any other dissolved organic materials still

present are absorbed by a granular, activated-carbon filter. Viruses and bacteria are then killed

by ozonisation. At this stage the water should be cleansed of all contaminants, but, for added

reliability, second-stage carbon absorption and reverse osmosis are used, and chlorine dioxide is

added to obtain the highest possible water standard.

The other main place that effluent is disposed of from is industry. Industrial plants put

their waste into the main drains, because they pump it into the main drains it has to be a

particular pH i.e. neutral (between pH6 and pH10). If the pH fluctuates out of this range, there

are valves along the main pipe line from the industrial works that close to prevent the effluent

leaking into the main sewage system. The pH can then be regulated by either adding caustic soda

(an alkaline) or hydrochloric acid to neutralize it again. If the valves did not close and the

effluent were allowed to travel into the sewage works then it would kill all the nitrifying and

denitrifying bacteria that break down the waste. The bacteria are very sensitive to the chemicals

that are used and if these levels fluctuate too much, it will kill the bacteria and the whole

decomposition process will be affected. The bacteria remove the ammonia in the effluent. There

are filters in the water treatment works that sieve out a lot of the suspended solids and there are

chemicals which are added to make the rest of the solids bind together with the help of bacteria

so that they come to the surface and can then be filtered off. The water that eventually comes out

is pumped from an outlet into the river unless it is to be recycled then it goes on for further

cleansing. The effluent that is pumped into the streams gives the decomposers in the water a

huge food supply, therefore they use up much of the oxygen and eutrophication - death of the

waterway - results. The decomposers deprive the other organisms such as fish and crustaceans of

oxygen causing them to die. This in turn affects the whole food chain.

Phosphates are products formed by the replacement of some or all of the hydrogen of a

phosphoric acid by metals. Depending on the number of hydrogen atoms that are replaced, the

resulting compound is described as a primary, secondary, or tertiary phosphate. Also known as

trisodium phosphate, tertiary sodium phosphate is used as a detergent