• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Water and Sewage Treatment

Extracts from this document...

Introduction

Plan: Water and Sewage Treatment The following describe how water from a reservoir is purified in treatment plant and how wastewater is treated and cleaned. Purifying Water in Treatment Plants As water leaves the reservoir, it passes through a screen to remove objects such as rubbish and twigs. Filters made from chemicals, sand and gravel remove smaller particles that could scour (wear away) the inside of water pipes, damage industrial equipment, or make drinking water cloudy. Bacteria or viruses, which may cause disease and death, are dealt with bubbling toxic gases, such as chlorine or ozone, through the water. Wastewater Treatment Raw sewage includes waterborne waste from sinks, toilets, and industrial processes. Treatment of the sewage is required before it can be safely buried, used, or released back into local water systems. In a treatment plant, the waste is passed through a series of screens, chambers, and chemical processes to reduce its bulk and toxicity. The three general phases of treatment are primary, secondary, and tertiary. During primary treatment, a large percentage of the suspended solids and inorganic material is removed from the sewage. The focus of secondary treatment is reducing organic material by accelerating natural biological processes. Tertiary treatment is necessary when the water will be reused; 99 percent of solids are removed and various chemical processes are used to ensure the water is as free from impurity as possible. ...read more.

Middle

Anaerobic 'digestion' of the sludge by bacteria such as Mathanobacterium converts the organic material into methane, carbon dioxide and hydrogen gases along with water and minerals. * In our experiment, after sedimentation, the effluent is passed through a column of different sized stones and sand. The largest stones should be at the bottom and the smallest at the top. Sand can also be used at the top of the column. Some important points to follow when making a rock column are to make sure the stones are clean and there are no gaps. This will remove any large insoluble particles that weren't removed during sedimentation. * The effluent that is collected after the rock column will be filtered at least twice through a filter funnel and filter paper. In industrial plants a process called Trickling Filter is used. In this process, a waste stream is distributed intermittently over a bed or column of some type of porous medium. A gelatinous film of microorganisms coats the medium and functions as the removal agent. The organic matter in the waste stream is absorbed by the microbial film and converted to carbon dioxide and water. The trickling-filter process, when preceded by sedimentation, can remove about 85 per cent of the BOD5 entering the plant. The following processes in our experiment are all forms of treatment following the filtering processes: * You may treat the filtered water with liquid chlorine or laundry bleach. ...read more.

Conclusion

* After at least two days the agar plate should be checked. If the agar plate is clear and there are no signs of bacteria present, then the water should be safe to drink. But if there are signs of colonies of bacteria forming then the water will be unsafe to drink. Variables * Instead of the sedimentation process the dirty water in our experiment can be passed through a series of sieves. The first filter would be the one with the largest pores and last one would be the sieve with the smallest pores. The sieves would mainly remove large pieces of material such as stones, sand dirt etc. * An alternative treatment replacing the use of bleach is to use Iodine tablets. * The purity of the water can be tested using agar plates after each of the individual processes in the experiment in order to see which one was the most effective. Prediction I think that the most effective form of treatment will be the distillation process and after a few days the agar plate will show no signs of bacteria present. If only the distillation process was carried out I would still predict that the distilled water would be pure. Distillation will separate the pure water from insoluble particles and anything else that was dissolved in the water. Any bacteria present will be eliminated due to the high temperature (over 100�C) reached. 1 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Green Plants as Organisms essays

  1. Investigation in to the effect of bile salts on the digestion of fat.

    Start recording the pH by using pH probes linked to the laptop via analogue to digital converter and immediately add 5cm3 of lipase solution, into each beaker. Stir the solution every 30 seconds. Record the pH change by printing off the data.

  2. Construct a rocket from a discarded PET (Polthylene Teraphetlate) drink bottle.

    Evaluation: So hence after using water as our variable we establish that by increasing the water level the horizontal range decreases. We also found from our experimental data that with 200 mL of water we got our furthest range. Over all the experiment has been a success and we have

  1. The effects of organic effluent from the seweage on the biodiversty in a freshwater ...

    decomposition of sewage.The chemicals that develop may be toxic and may result in an almost lifeless river. NULL HYPOTHESIS: The diversty of organisms in the fresh water stream will not change as the organic effluent decreases when we move away from the seweage.

  2. Investigation of Biochemical Oxygen demand (BOD) Concentration in Effluent from a Sewage Treatment Works

    source; Gray N.F 1999 pg 67 From table (1) above it can be observed that as water gets warmer, there is a reduction in dissolved oxygen (DO), this is because the oxygen molecule becomes energised and diffuses to the water surface thereby leaving fewer dissolved oxygen in water.

  1. Lagging Pipes.

    From the results of this experiment however, I have concluded that 4 layers of bubble wrap is the most effective thickness out of the range that I have tested. This is because as it is quite thick, the heat cannot conduct as easily through it.

  2. Batch Distillation.

    When the fractionating column is operated at a constant reflex ratio, it cannot compensate for the steady the top product must also get less and less. The boiling point temperature of a mixture of two liquid components depends on both the boiling points of the pure components and the proportion of each component in the mixture.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work