Introduction to Sustainable Development

Answer sheet

Concluding Consequences: Part 2

  1. Use the given flows to cipher all the staying flows that have non been specified in the Coursework papers. Write all the flow rates ( i.e. the flows in t/day ) on the flow diagram ( demoing all computations below ) .(6 points )

7920t4320t/day

7920t/day7920t/day

9600t/Day 8640t/day

15840t/day

3600t/day

-480t7920t/day

7920t/day

3600t/day

-6720t/day

6720t/day

480t/day

48,000 people * 200L /person /day = 9600000 L/day.

Assuming H2O is 1kg/L. Therefore 9600000 L/Day = 9600000 kg/Day

= 9600 tons/Day. Using information for 1 twenty-four hours.

Primary intervention removed 480 t. Therefore 9600t – 480t = 9120t. Add 6720t of RAS

= 9120t + 6720t = 15840t to travel to Aeration armored combat vehicles.

It is split so 15840t/2 = 7920t goes in each armored combat vehicle.

4320t are discharged each twenty-four hours from each armored combat vehicle. So 7920t – 4320t = 3600t are left in each armored combat vehicle.

3600t * 2 = 7200t sum activated sludge. Remove 6720t in RAS.

7200t – 6720t = 480t is left as waste activated sludge to be disposed.

Calculations /working notes

You are required to demo for each inquiry how you arrived at the concluding consequence in the box “Calculations / working notes” given on the right-hand side of theAnswersheet. The concluding consequence should be entered in the box below each inquiry.

Concluding Consequences: Part 2Calculations /working notes

9600000 L/day = 9600 t/Day – 480t in primary intervention go forthing 9120t come ining secondary intervention.

At 400 milligrams O2/l this is a sum of 9120000L * 400 milligram O2/l = 3648000000400 milligram O2

Converting milligram to t by multiplying by 1/100000000 gives 36.5t of O2entire per twenty-four hours. Full digestion would so necessitate 36.5 T of O2.

As initial BOD is 400 milligram O2. and concluding BOD is 15 milligram O2. The decrease efficiency is 15mg /400mg = 3.75 % staying translates into an efficiency of 1- staying = 1-3.75 % = 96.25 %

And so since this STP merely removed 96.25 % of the O2the entire O2removed per twenty-four hours is 35.1t of O2per twenty-four hours.

To cipher the O degree in the river after the wastewater is released use the equation C = Co ^ – ( Kx / U )

Where Co is the original O2/l, Kx is the BOD and U is the watercourse flow.

This gives

C= 9 milligram O2/l ^ – ( 15 mgO2/l / 1500 milliliter3/s )

C= 9 milligram O2/l ^ -1.01

C = 7.9 milligram O2/l

The river’s dissolved O is lowered to 7.9 milligrams O2/l. The dilution of the wastewater causes a 12 % bead in oxygenation degrees. This is non ideal but any BOD at all will do a bead in dissolved O degrees. Depending on demands of the river this may be important or non.

  1. Given the mean BOD5value of the waste H2O of 400 milligrams O2/l, calculate the sum of O in t/day needed for complete digestion of the waste H2O undergoing secondary intervention.(4 points )36.5t of O2is needed to wholly digest the waste H2O to 0 % BOD5
  1. What is the overall BOD decrease efficiency?

(2 points )

The overall BOD5decrease efficiency is 96.25 % as consequence is 15 % BOD5

  1. The concentration of dissolved O in the local river before the treated H2O is discharged is on mean 9 milligram O2/l. If the river flow rate is 1.5 m3/s and the treated H2O is discharged with a residuary BOD5of 15 mgO2/l, calculate the mean O concentration in the local river after the staying BOD of the waste H2O is met. Is the dilution of the treated wastewater sufficient to guarantee that the O degree in the river H2O is non significantly lowered?

(8 points )

7.9 milligram O2/l is the lowered concentration of the river. This constitutes a bead of 12 % and may hold important consequence on the river’s ecosystem.

Average energy usage by Vitox system is ( 0.9 MJ/kg + 1.1 MJ/kg ) /2

= 1.18 MJ/kg mean energy usage.

Cryogenic separation ( big graduated table ) uses 1.1 MJ/kg so Vitox and Cryogenic ( big graduated table ) uses norm of 1.18 MJ/kg + 1.1 MJ/kg

= 2.29 MJ/kg O2.

Using cryogenic ( little graduated table ) separation = 1.8 MJ/kg + 1.18 MJ/kg

= 2.98 MJ/kg O2.

Using PSA ( big graduated table ) = 3.7 MJ/kg + 1.18 MJ/kg = 4.88 MJ/kg O2.

Using PSA ( little graduated table ) = 6.0 MJ/kg + 1.18 MJ/kg = 7.18 MJ/kg O2.

Oxygen coevals systems mean = 1.1 MJ/kg O2+ 1.8 MJ/kg O2+ 3.7 MJ/kg O2+ 6.0 MJ/kg O2= 12.6 MJ/kg O2/ 4 = 3.15 MJ/kg O2.

For Paddle Aerators

Energy usage is 1.5 MJ/kg O2to16.7 MJ/kg O2, an norm of 9.1 MJ/kg O2

 

Coarse bubble diffusor

Energy usage is 3.03 MJ/kg O2to 4 MJ/kg O2, an norm of 3.5 MJ/kg O2

Fine bubble diffusor

Energy usage is 1.0 MJ/kg O2to 2.38 MJ/kg O2, an norm of 1.69 MJ/kg O2

For Vitox the norm is 1.18 MJ/kg O2+ 3.15 MJ/kg O2= 4.33 MJ/kg O2

Concluding Consequences: Part 2Calculations /working notes

  1. Calculate the entire mean energy usage for the VitoxThuliumengineering, taking into history the energy used for O coevals in different air separation workss every bit good as the energy used by the engineering itself at the STP. Compare these consequences with the mean energy used by the other aeration engineerings. Which option would you take on the footing of energy usage and the associated environmental impacts?(8 points )

Vitox:

2.29 MJ/kg O2

– Cryogenic separation ( big graduated table )

2.98 MJ/kg O2

– Cryogenic separation ( little graduated table )

4.88 MJ/kg O2

– Prostate specific antigen ( big graduated table )

7.18 MJ/kg O2

– Prostate specific antigen ( little graduated table )

9.1 MJ/kg O2

Paddle Aerators

3.5 MJ/kg O2

Coarse bubble

Diffuser

1.69 MJ/kg O2

Fine bubble

diffusors

Fine bubble diffusors

Preferred engineering on the footing of energy usage?

Consequences: Part 2Calculations /working notes

To acquire the from works to the STP requires: 1kg Oxygen2* 0.5 MJ/kg = 0.5 MJ necessary for transit.

Cryogenic works ( big graduated table ) = 1.1 MJ/ kilogram O2* 1 kilograms O2= 1.1 MJ necessary. To present it takes 1.1 MJ + 0.5 MJ = 1.6 MJ

Smaller graduated table PSA works = 3.7 MJ / kg O2* 1 kilograms O2= 3.7 MJ

For 1kg of Oxygen to be utilized

Vitox has a 95 % efficiency evaluation so 1kg of pure O2would ensue in a 50g of O2get awaying into the ambiance.

Paddle Aerators have an mean efficiency evaluation of 5.5 % and can utilize merely air. To provide 1kg of O2the sum of air necessary is 1kg / 0.21 = 4.76 kilogram.

Due to the low efficiency evaluation 945 g of O2would get away into the ambiance.

Coarse bubble diffusion has an mean efficiency evaluation of 5.5 %

and can utilize merely air. To provide 1kg of O2the sum of air necessary is 1kg / 0.21 = 4.76 kilogram.

Due to the low efficiency evaluation 945 g of O2would get away into the ambiance.

Fine bubble diffusors have an mean efficiency evaluation of 14.5 % and can utilize merely air. To provide 1kg of O2the sum of air necessary is 1kg / 0.21 = 4.76 kilogram.

Due to the low efficiency evaluation 855 g of O2would get away into the ambiance.

  1. Calculate the entire energy used by the large-scale cryogenic works to bring forth and present 1 kilogram of O to the STP?

How does that compare with the energy required by an on-site little graduated table PSA works?(2 points )

The entire energy needed to bring forth and transport 1kg of O2per twenty-four hours in the Cryogenic works is 1.6 MJ. In the smaller graduated table on site PSA works is it 3.7 MJ.

  1. When comparing this to on-site O production, do you believe transport is an of import consideration?

(1 point )

Transportation is an of import consideration

  1. What do you reason: is a smaller size works based at the STP a better option than the large-scale works off from the STP? Explain briefly why?(1 point )Large graduated table. Uses less energy and could function more than 1 works.
  1. Calculate the sum of air that has to be supplied for the different aeration engineerings and the sum of unutilised O that escapes into the ambiance(8 points )

Air = 0 as it uses O.

50g of each 1kg flights

Vitox

Air = 4.76kg. 945g of each 1kg flights

Paddle Aerators

Air = 4.76kg. 945g of each 1kg flights

Coarse bubble diffusor

Air = 4.76kg. 855g of each 1kg flights

Fine bubble diffusors

For the remotion of 35.1t of O2per twenty-four hours.

Vitox has an efficiency of 1.18 MJ/kg O2and a loss rate of 5 % of the O2.So to cipher the energy demand usage 35.1t + 35.1*.05 = 36.9 T is to be processed by the Aerators per twenty-four hours if loss is taken into history.

Entire energy used is 1.18 MJ/kg O2*36.9t = 43542 MJ/day.

To include the cost of O2isolation use an mean entire MJ of 4.33 MJ/kg O2* 36.9t = 159777 MJ

+ conveyance which is 36.9t * 0.5MJ/t = 18.5 T

Entire = 159795 MJ

 

Paddle Aerators have an efficiency of 9.1 MJ/kg O2and a loss rate of 95 % of the O2

So to cipher the energy demand usage 35.1t + 35.1*.95 = 68.45 T is to be processed by the Aerators per twenty-four hours if loss is taken into history.

Entire energy used is 9.1 MJ/kg O2*64.45t = 789500 MJ/day.

 

 

Coarse bubble diffusors have an efficiency of 3.5 MJ/kg O2and a loss rate of 95 % of the O2

So to cipher the energy demand usage 35.1t + 35.1*.95 = 68.45 T is to be processed by the Aerators per twenty-four hours if loss is taken into history.

Entire energy used is 3.5 MJ/kg O2*64.45t = 428600 MJ/day.

 

 

 

Fine bubble diffusors have an efficiency of 1.69 MJ/kg O2and a loss rate of 85.5 % of the O2

 

So to cipher the energy demand usage 35.1t + 35.1*.855 = 65.1 T is to be processed by the Aerators per twenty-four hours if loss is taken into history.

Entire energy used is 1.69 MJ/kg O2*65.1t = 110019 MJ/day.

Concluding Consequences: Part 2Calculations /working notes

  1. Calculate the day-to-day energy demand in MJ/day for runing each of the aeration processes at the STP.(8 points )43542 MJ/day

Vitox

586495 MJ/day

Paddle Aerators

225575 MJ/day

Coarse bubble diffusors

110019 MJ/day

Fine bubble diffusors

Vitox

Which is the most energy efficient procedure?

  1. What is the entire energy demand in MJ/day for runing the Vitox procedure if you include the energy required for production and conveyance of the O demand of the procedure? Which is, hence, the most energy efficient procedure overall?(6 points )

159795 MJ is energy required for production and conveyance of O is factored in. This makes the most energy efficient procedure overall Fine Bubble Diffusers.

Concluding Answers: Part 2

  1. On the footing of the consequences obtained, rank the procedures in order of their desirableness. Complete the tabular array below, naming all relevant considerations, and so rank the engineerings in order of penchant on a graduated table of 1 to 4, with 1 bespeaking the best option and 4 the worst.(4 points )
Considerations Paddle aerators Coarse bubble diffusors Fine bubble diffusors Vitox system
Oxygen use 3-4 3-4 2 1
Oxygenation efficiency 3-4 3-4 2 1
Capital costs 3-4 1-2 3-4 1-2
Operation costs 4 3 1-2 1-2
Energy efficiency 4 3 2 1
Life rhythm energy efficiency 4 3 1 2

Overall

4 3 2 1

Discussion Questions: Part 3

  1. What societal service is provided by a sewerage intervention works? What are the benefits of handling waste H2O?(6 points )The societal services that are provided by a sewerage intervention are legion and valuable. The most primary service that it provides it assisting refilling the sum of fresh H2O available on the planet. It doesn’t really increase net sum but restores what we are utilizing at a high rate than allowing the H2O sublimate of course. With the desperate heterosexuals of the sum of available fresh H2O on the planet and worlds increasing their diminishment of the available beginnings the H2O intervention installations are critical to assisting detain the at hand H2O crisis. Secondarily the intervention works helps to decrease the rate of human pollution of the planet. By doing serious attempt to better the province in which H2O is returned to the environment after human usage it helps the environment by enabling biology to last as opposed to dumping contaminated H2O which harms the environment. The 3rd benefit is strictly ascetic in that it improves the expression and odor of our waterways.
  1. How can people be encouraged to cut down H2O ingestion and hence the sum of waste H2O generated? What should authoritiess make to advance decreased H2O use?

(6 points )

Peoples can be encouraged to cut down waste H2O through authorities action and public instruction. Government has a cardinal function to play as they set policies and are able to set fiscal inducements in topographic point to promote citizen behavior. By giving pecuniary inducements for concern and persons to run into authorities environmental criterions more of these groups are likely to take action to run into these ends. Education, authorities organized or non, is besides critical. The authorities is finally responsible to the people and unpopular authorities policies will ensue in eviction of the authorities. Public instruction through NGOs and authorities is critical to promote alteration but it will take a comprehensive attempt from pedagogues, pioneers, authorities and concern to consequence any existent alteration in the manner people treat H2O.

  1. Why are noise and odour of import societal considerations when be aftering a H2O intervention works?(6 points )

Noise and smell are of import societal considerations when be aftering a effluent intervention works, as it is of import to restrict break to the people populating near the works. Social acceptableness comes into the image when sewerage intervention is involved the NIMBY syndrome is to the full engaged when there are programs to set a noisy smelly anything in someone’s back yard. Dumps, sewerage intervention workss and main roads all cause perturbation and have the potency to take down the quality of life for the people near they are built. To minimise societal resistance to the arrangement of a effluent works it is of import to stress the benefits that the works provides to the people of the country and doing maximal attempt to minimise the negative effects of such a works. Peoples don’t like a sewerage works they can hear and smell everyday, they prefer one they don’t even know is at that place.

  1. Peoples normally reject proposals for siting of a sewerage intervention works ( or any other works ) in their vicinity. This is known as the “NIMBY” syndrome. What are your positions as an applied scientist or scientist on such reactions by local communities? What strategies can be used to cover with the NIMBY syndrome?(6 points )

The NIMBY is an unfortunate side consequence of our broad democratic society where the accent of on ego, non the group as a whole. If the outlook were a group outlook people would accept that sewerage workss have to be placed someplace and sometimes it happens to be in their vicinity. However people are more captive on taking any nuisance from their ain lives, frequently volitionally nescient of where it goes every bit long as it doesn’t travel anyplace near them. As a scientist, and a individual, this is apprehensible, as no 1 wants their ocean position to go a community shit. It is because of this that scientists and applied scientists can understand the wants of the populace and purpose to do effluent workss as least intrusive as possible.

The best scheme for NIMBY is rationalisation that the location was chosen because it was the best location for such a works. It is besides of import to guarantee that the least figure of people are affected and that the people that are affected are done so in the most minimum manner possible. No 1 will object to an odourless unseeable sewerage works and applied scientists, contrivers and scientists should do their best attempt.

  1. Analyze the engineering rankings you made in inquiry ( L ) and so do a determination on the most sustainable aeration engineering, presuming that you are Head of Engineering Division in a company. Explain your pick.(6 points )

As the Head of the Engineering Division I tend to take the Vitox method for its aeration efficiency. Ideally with proper financess I would be able to put up a works to bring forth the O necessary on-site so transit costs are lowered. It is the best for operating costs and capital costs so the works would hold a lower budget. The one thing I would be worried about would be the cost of energy as the Vitox method does utilize more energy than the Fine bubble diffusors but the possibly of repossessing some of the energy back through use of waste merchandises from the works would be investigated.

  1. Using the same consequences, assume that you are a local occupant and do a pick of the most sustainable engineering. Explain.(6 points )

As a local occupant I would probably take a engineering that would chiefly minimise the effects on me and my community and secondarily 1 that would minimise cost, as my revenue enhancement dollars will most probably be paying for the works. Without equal information on the environmental branchings of each of the options it would be hard to do a pick without outside information. Ideally I would wish to inquire a local academic, people in other towns to see which they have and what experiences they have had, every bit good as local concern people to see their sentiment. In short I would necessitate much more information as aeration efficiency doesn’t affair to me – I want information on the seeable effects of the workss types. If the outside consequence is the same for all so I would take the cheapest and longest lasting.

  1. Using the same consequences, assume that you are an environmental militant and do a pick of the most sustainable engineering. Explain.(6 points )

As an militant I may non take any of those options. There are other solar bioremediation techniques that could be used with less energy. Construction of wetlands to farther sublimate the H2O coming out of the works would besides increase environmental friendliness while bing small. However if I was forced to take between all the systems I would take the Fine Bubble Diffusers for their low energy costs as no excess processing of O is necessary. It seems to be the most effectual when it comes to utilize of air. Other than energy usage there is nil truly dividing the different intervention options for me. I would take any except the Vitox as it requires excessively much energy, necessitates building of roads and/or excess edifices. Overall I would travel with a less mechanical and more natural method but with the above picks it’s Fine Bubble diffusion.

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