Assignment for Environmental Engineering
Q1.
Answer : Water treatment follows basic three steps:
1: Primary treatment
2: Secondary treatment (Microbial treatment)
3: Tertiary Treatment
About 10 billion liters of water is treated every day in England and Wales. Sewage is the mixture of different types of waste accommodate from various sources. It consists of solid waste that during the processing settle down at the bottom of the tank.
Role of microbes for sewage treatment:
The contaminated liquid is pour into a big aeration tank having groups of microbial community. Then there is mechanical mixing of the tank’s content with air or air bubbled through the tank. The organic materials in the sewage are then used by the microorganisms. The rotten organic matter in the tank provides the microbes with the food used for respiration.
The microbes circulate the flow of air(oxygen) in the water and break down the CO2 into simpler components. The heavy waste material then gets small and easily flushes out with fresh water. Hence leaving the sewage water clean and usable.
Q2.
Answer: The main cause of global warming arises from the air related areas. The harmful chemicals when released in air results in it’s contamination and the pollutants sometimes, are capable of entering into respiratory system by inhalation process.
Major causes:
- Industrial waste: The chemical reactions results in generation of harmful pollutants and gases that when comes into contact with the fresh air create smog (sometimes heavy and sometimes lite). These clouds of chemicals then flow over many areas and react with their surroundings. Inhalation of such air can lead to many problems like Asthama, Eye burning etc.
- Automobiles: The fuel used in our cars is a combination of ethanol and other petroleum components. When released in open air mixed with the atmospheric culture and create havoc for breath related patients.
- Fire: There are some causes that don’t involve human actions but still contribute to this problem. These are forest fires.
Forest fire is the result of friction that occur between two rough and dry surfaces capable of producing spark and then get involve with other similar materials and cause huge fire scenarios.
Research study : A recent has shown up that the overall effect of such harmful gases is resulting a hole in Ozone. Ozone is the outer most layer of the atmosphere the protect us from ultraviolet rays and other harmful gases.
Measures:
- Reforestation- An effective way to purify the air naturally with the help of trees and plants. In recent years we have seen a drop of 10-15% of forest cut down and this is something we need to pay attention on.
- Use of public vehicles- Minimum use of private vehicles can save us a little bit from this serious issue.
- Air purifier: Air conditioners that we use consume heavy electricity and in exchange produce CFCs(Chloroflouro carbons) .
Q3.
Answer: The water treatment principles involve following terminologies-
- Coagulation: The process involves accumulation of solid particles by setting the water for some time. This is also done by adding chemicals that fasten this process. Catalysts act for tis process and increase the process speed.
- Filtration: Filtration terms for the shreading things that are not made for that section. In sewage treatment we have filtration sections that are working for passing only the allowed particles depending upon their sizes.
- Sedimentation: Sedimentation is the process that includes the sediments to settle down on the tank surface for adding some kind of materials suitable for this action.
- Flocculation: This process terms for making forth that is form by the accumulation of particles and float over the water surface.
- Biological Treatment: The contaminated liquid is pour into a big tank for aeration consisting a complex community of microbial groups.
The microbes circulate the flow of air(oxygen) in the water and break down the CO2 into simpler components. The heavy waste material then gets small and easily flush out with fresh water. Hence leaving the sewage water clean and usable.
- Solid handling : This step involves the process of disposing the solid using the proper guidelines and these are basic since some of these are disperse to the crop filed for making them fertilizers.
- Disinfectant: This step comprises of adding chemicals to the sub-cleaned water. Chemicals like bleach is use for making the water free from smell and other small microbes.
Chemicals like Alum is use for making the water colorless.
- Advanced treating Process: Advance treatment involve the purifies that make water drinkable by eliminating the microbes using carbon and activated charcoals.
Unit processes like: Oxidation and coagulation
Oxidation is the process in which redox or reduction takes place and one atom compound will gain one electron from another compound.
Q4.
Answer : The urban storm water is the combination of different types of impurities that get involved in it during water washoffs.
The storm water contains soluble that are from road, parks, fields etc and sometimes contains toxics and make that water imperfect for drinking and washing purposes. This make this calamity so dangerous and harmful for living creature.
Contaminates in urban storm water :
- Petrochemical : The chemicals that comes from the contact from various sources like factories, industries.
- Toxicants: these comes from pipes that are responsible for taking out such toxics and get damage by the thunder.
- Plastics and rubber: The urban areas are heavily dump with plastics and rubber for daily use. During such calamity these things get wash off with water and cause blockage and other problems across the path flow.
Contaminates in agricultural water:
- Fertilizers: The crops are nourished with fertilizers and other substances that are useful in term of killing the harmful substance and pests.
- Damaged crops: the crops get wash off by the strong water flow and moved out of their way along with water. These when spoiled generates unpleasant smell and sometime causes breath related problems.
Q5.
Answer: Recyling the waste from the various substances are useful and can be used for other similar purposes. The things we use in our day to day life are used for making the other various things such as-
- Plastics: On large scale, plastics are uses for making roads and pathways for public transport by melting the plastics in a hot furnace. Plastics have strong holding capability and hence are uses for area that required high strength.
- Rubber: Rubber are uses for making tyre and other vehicular elements that require hardness. These are recycles by mixing substances and these substances sometimes are more into chemicals to strengthen the substance.
- Metals: Metals can be re-melt to cast into various mold. Since metals can’t be use for degrading and soil fertility purposes hence they are transfer to industry and mixed with some powdered material to clean and then cast into different shapes.
- Paper: Paper are purely degradable substances that are uses for making the substances like books, newspaper etc. Papers are treated with proper operations and can be made into some clean dump from which we can take out our usable piece.
- Glass: Glass is also one those materials that are uses again by melting and casting. Glass contains impurities that are reduced or eleminated by adding lime powder and then treated under high temperature to make a usable piece.
Advantages:
- Cost: The cost of the production is very less in comparison to the new making materials.
- Resources: Th resources use for making new substance out from the raw materials is large from that use in making out something from old one.
- Electricity: Energy use for making new glass/plastic/rubber substance is much larger than the one from old one.
- Cleaning environment: Reusing the substances will result in cleaning action in the environment. Since we’ll be using unused products by making them into something more desirable.
Disadvantage:
- Quality: The quality of the resulting product will not be equal to that of the raw one.
- Time: It requires a lot of time to make recycles product.
- Labour: The man power require for such processes is much high then that of raw one.
- Health: Due to working in such environment, the person suffers from disease that are hitting the person’s health.
Q6.
Answer: According to the report from ASCE, the grades for America’s drinking water and waste water infrastructure is ‘D+’.
The report issue on 2017 by American Society Of civil Engineers declared the American standard as ‘D+’ for Drinking Water and Infrastructure.
Ii) Funding for improvement: Under the current scenarios, EPA has estimated that current budget provided by the authority may be more than $2 billion in water and infrastructure investment.
Iii) Challenges:
- Population: the increasing population will hit an impact over the water infrastructure.
- Resources: The present resources are not sufficient to make the changes appropriate.
- System: For making changes for such a high governance for such a huge community is very much important to be working fine with unbiased nature.
Q7.
Answer: Given-
Length: Width = 4:1 and Width: Depth = 1:1
Equating these values:
L\W = 4\1 gives
L= 4W ——–(I)
Also, W\D = 1\1 gives
W = D ———(ii)
Since we have given, D = 30 feet, So from eq (ii) we have,
W = D = 30 feet. ———(iii)
Applying eq (iii) in eq (I) we have,
L = 4W = 4 * 30 = 120 feet.
Now we have ,
L= 120 feet, W = 30 feet, D = 30 feet. Calculating the volume,
V = L*W*D
= 120 * 30 * 30 = 108000 cubic feet (Answer)
Q8. .
Answer: Given
Diameter = 35.
1) For cross-sectional area: R*R
We know that –
D = 2*R so from here we have,
R = D\2 = 35\2 = 17.5 ——–(I)
From I we have
Cross sectional = R*R = 17.5*17.5 = 306.25 sq meter (Answer for Cross-sectional area)
2) Circumference : 2*3.14*R
From above result we have = 2 * 3.14 * 17.5
= 109.9 meter. (Answer for circuference)