SBEP1323 Urban Engineering Exam: 06 June 2018

Question #1:

Discuss five (5) methods of Low Impact Development (LID) to control surface runoff in an urban area.        

(5 marks)

What is the infrastructure that needed by a modern urban area and discuss why it is needed. Give one (1) related example.  

(5 marks) 

 

Question #2:

If the shape of all channels are square (depth=width), made of concrete n=0.015, and channel slope S=0.005, rainfall intensity I=100 mm/hour, design secondary and tertiary drainage channels in the area as shown in Figure 1. Data for the purpose of design are shown in Table 1.

[NOTE: Q=0.278*C*I*A, Q=w*d*1/n*R^(2/3)*S^(1/2)].

Table 1:

Figure 1:

(10 marks)

Question #3:

The existing solid waste management system in a city is business-as-usual SWM, with the capacity of landfill site is 2 million tons and has a life-span of 30 years (10,950 days), and daily waste generation is 1,800 ton/day. Waste disposal to landfill site after the implementation of strategic action plan is maximum 10%. To accomplish a sustainable SWM:

  1. List two (2) activities of strategic action plan for each element, in column C (Table 2).
  2. Estimate the percentage of each element of SWM after strategic actions were implemented, in column D (Table 2).

Table 2:

(10 marks)

 

Question #4:

A wastewater treatment plant will be constructed in an area. The average daily flow is 150 liters per PE, and the service area has the followings:

  • 2,000 units of various types of houses
  • 10,000 m2 of commercial area
  • 10 primary and secondary schools that can cater 250 students each school
  • 10 kindergartens located in the residential area that can accommodate 25 children each kindergarten
  • 5 mosques that can simultaneously accommodate 3,000 people
  • 2 churches or 2 temples that can accommodate 1,000 people
  • 1 wet market consist of 100 unit stalls
  • 20 public toilets at various places

Minimum capacity of Wastewater Treatment Plant can be calculated by the following formula:

Q=4.7*(PE/1000)^(-0.11)*DF

Where DF=0.15×PE in m3/day. PE is shown in Table 3.

Estimate the capacity of waste water treatment plant.                                       

(10 marks)

Table 3:

Question #5:

To serve a part of the city, which consist of residential areas, industrial areas and commercial areas, treated water is supplied to the area with an average flow of 700 m3/hour. The daily mass curve is shown in the Figure 2. If a cylindrical tank is used with diameter twice of its height, design the tank dimension.

(10 marks)

Figure 2:

Key Answer can be downloaded here: Answer Script Final Exam 2018 – 06 Jun 2018 – Web

 

The solutions: student’s way!

Here are the solutions offered by the group.

Solutions offered by Group 1:

Group 1 offers equal percentage for almost all elements of solid waste management. Interestingly, they believe that recycling waste and establishing waste bank would be able to reduce waste disposal by increasing it from presently 10% to 30%. They argued that recyclable wastes are abundant, and establishing more recycling factories is one of the ways. The group also offers a zero waste action plan within an action plan? what kind of action plan is that? you must deliberate it guys.

Solutions offered by Group 2:

This group is so ambitious by increasing waste reduction from 5% to 30%! The problem is how. Increasing waste reduction will affect citizens’ convenience very much. If you will be able to reduce consumption drastically, might be ok. But, is it possible?

Reuse will be increased from 5% to 20%! In Malaysia, I think it is hard to accomplish. A simple example, repairing a stuff will cost you 30-50% of buying a brand new stuff. So it is economically infeasible. I had a sofa that needs to repair, but when I asked the repair shop, he sets the cost of repair of RM 690. Meanwhile the price of new equivalent sofa is about RM 499. Considering this situation, my options are two: (1) dispose the sofa (2) self-repair the sofa. Since our family advocates to minimize the household waste, then self-repair the sofa is the best way.

Solutions offered by Group 3:

Not much can be expected from this Group.

Solutions from Group 4:

Solutions offered by this group seems more realistic ones. However, they do not want to increase the contribution of waste to energy program in reducing waste disposal.

Solutions offered by Group 5:

Almost similar target with group 4, though the strategic actions are lack of focus for all groups.

The weaknesses of all groups are they could not offer straightforward and reliable actions to accomplish the goals. From the simulation, students will understand how difficult to accomplish sustainable solid waste management.

Group Simulation

When I delivered a class on solid waste management, I challenged students to solve the persistent problem faced by most cities in developing countries on solid waste management. In fact, most cities in under developed countries are doing a business-as-usual management of municipal solid waste, which is essentially a process of collect – transport – dispose – and forget. This is not a sustainable kind of solid waste management, because of several reasons such as (1) creating NIMBYs by landfill site (2) generating more pollution (3) consuming more resources. A sustainable solid waste management must involve waste reduction, reduce, reuse and recycle (3Rs), waste composting, waste to energy program (if possible), and most importantly, reducing waste disposal to landfill site, and zero waste!

To feel the sensation on how hard doing sustainable solid waste management is, I divided the students in five groups and they have to solve the issues I prepared in a piece of paper.

Here is the issue:

A city is facing problems on solid waste management. The city has only landfill site with 5 million ton capacity, and it is expected to have a life span of 25 years. Mayor of the city is then change drastically the approach on municipal solid waste management from business as usual to sustainable waste management. It must be reflected in the increase of good practices such as waste reduction, 3Rs, increasing waste-to-energy program, composting, and to reduce waste disposal to landfill site. A doable and reliable target is set to reduce waste disposal from currently 70% to 10% after strategic actions are implemented. Students must prepare sets of strategic actions to change from business-as-usual SWM to sustainable SWM with the hierarchy of increasing waste reduction, 3Rs, composting and waste recovery, and reducing waste disposal. How much is the increase or reduce, is up to the students to ponder.

The students are challenged how to solve it. The solution must be discussed in the class in group.

Discussion in Group 1

Discussion in Group 2 and 3

Group 4

Group 5

Students are allowed to consult Mr. Google to find the solution, with one condition that they understand the solutions offered by Mr. Google.

Student’s solutions will be presented here.

I am quite unhappy with your achievement guys …

I am quite unhappy with the accomplishment of this 2017/2018 batch of students in comparison to their seniors, though I could not conclude that the student’s quality is degrading.

Here are Descriptive Statistics of Batch 2014, 2015, 2016, 2017 and 2018 for the same subject, same method of teaching although some improvement involving  interactive teaching and NALI starting Batch 2016 onward has been applied, and same standard.

Certainly, Batch 2014 is the best students cohort so far. Take a look at the best student in this subject with almost perfect grade 96.1/100.0. I always avoid subjective marking by providing quantitative questions i.e. measurable response of students. Should I provide a subjective kind of essay questions, I would be make sure two things: (1) clear rubrics and (2) minimum percentage of essay questions.

Batch 2018 (current class) is so far the awful cohort plus laziest students. Many procrastinators in this batch such as late submission of assignment. The percentage of procrastinator is also high, sometimes accounted for 30%, which it might not be found in previous batch (their senior).

Batch 2014, number of student: 23, Mean of Grade: 83.73

 

Batch 2015, number of student: 28, Mean of Grade: 79.57

 

Batch 2016, number of student: 57, Mean of Grade: 80.58. We observe that the minimum grade of this batch is 0.0. This is because 1 student withdrawn from the batch is included in the analysis.

57 students:

56 students (1 student withdrawn from study and dropped the class): Mean of Grade: 82.0

 

Batch 2017, number of student: 35, Mean of Grade: 76.27

 

Batch 2018, number of student: 33, Mean of Grade: 70.62

 

Assignment #2 Planning and Design of Urban Drainage – Part 2

Here is one of the solutions:

[Again, please note that this solution is for planning students only, since they need only for planning purpose. Thus the only approximate drainage channel dimension will be necessary. For civil engineering students, more complicated calculation involving hydrograph, time of concentration, exact catchment area and flood routing will be necessary. Also, the shape of drainage channel for planning students is most simple possible such as square or rectangular. Meanwhile for civil engineering students, the cross-sectional shape can be any shape.]

There are three zones in urban areas: (1) residential area with C=0.80 (2) greenery with C=0.35 and (3) commercial area with C=0.90. Because of no further information in the problem, and looking at hypothetical map available, suppose we are going to construct drainage channel with separate tertiary/secondary channel for different zones, with the following arrangement (considering the catchment area to be served):

Slope of the channel can be approximated by minimizing cut and fill.

Secondary channel’s longitudinal slope can be taken as 0.018, and tertiary channel as 0.005.

And, the dimension of channels is shown in table below.

The drainage channel layout is shown below.

Assignment #2 Planning and Design of Urban Drainage – Part 1

I usually provide Assignment with a ‘complete state’, everything is available, which means any single information required to solve the problem is available in the assignment. This has made students are too lazy to innovate and encourage their creativity, or use their judgment. This time I do not give student a complete-state assignment. Students must find other information from other sources or use their judgment (not wild judgment or guessing). Here is the problem I gave the students in Assignment #2 Planning and Design of Urban Drainage.

To avoid flood in an urban area (see Figure below), an urban drainage system that consists of secondary and tertiary drainage channels will be constructed, while primary canal will utilize existing river. The urban area consists of residential area of 15 hectares with runoff coefficient C=0.80, greenery of 5 hectares with C=0.35, and commercial/industrial area of 10 hectare with C=0.90. The hierarchy of drainage canal is as the following illustration:

The plan:

Typical cross section of secondary and tertiary drainage channel:

and the Map:

Your tasks: (you can use your academic judgment to assume additional necessary information)

Based on a semi-hypothetical map:

  1. Design your urban drainage system, which consists of tertiary and secondary (you can use existing river for primary drainage channel). You can use this formula for your design: Peak Discharge: Q=0.278×C×I×A (Q in m3/sec, I is 100 mm/hour, A in km2). 1 km2 = 100 hectares. Channel Capacity: Q=[Cross Section of the channel]×[1/n]×R0.67×S0.5 and R=(w×d)/(2d+w) and S=channel slope. You can obtain the necessary information from the Map (7 points).
  2. Plot your drainage system into provided map (NOTE: use RED color for secondary channel, and BLUE color for tertiary channel). (3 points).

Obviously students need to find other information required to solve the problems, such as longitudinal slope of the drainage channel (S), n Manning (depending on the material used for the channel), and extent of the catchment area for secondary and tertiary drainage channel. This information is actually available in the problem, but it needs student’s creativity to find it.


Here is one of the solutions:      

[Please note that this solution is for planning students only, since they need only for planning purpose. Thus the only approximate drainage channel dimension will be necessary. For civil engineering students, more complicated calculation involving hydrograph, time of concentration and flood routing will be necessary.]

To be continued in Part 2.

 

 

Field Visit #3: Explanation 3

After chlorination process, the final product of this WWTP is water with B standard effluent. In Malaysia, there are Standard A and Standard B for effluent. Standard A has higher quality and better characteristics and thus can be directly processed by drinking water treatment plant. And of course, the unit cost of wastewater treatment is higher than Standard B.

Here is the Malaysian Standard of Effluent.

The water processed in Bukit Indah Waste Water Treatment Plant meets Standard B and discharged directly to Sungai Melana, Sungai Skudai and Danga Bay.

We, all students and lecturer, would like to express our thanks and appreciations for the reception by Indah Watar Konsortium.

Field Visit #3: Explanation 2

Fat, oil, coarser sediments and some unwanted substance were removed during the process in aeration tank. The wastewater is then discharge to Clarifier Tank. The function of this process is to remove finer sediment and other unwanted substance.

The wastewater is discharged by using rotating arm, the water is trickled from above to bottom of the clarifier through filter. Filter is usually made from sand and gravel. Before the water enters the clarifier, coagulation and flocculation reagents can be added. These reagents cause finely suspended particles to clump together and form larger and denser particles, called flocs, that settle more quickly and stably.

Clarifier with rotating arm

Students listen to explanation on clarifier

Water discharge from clarifier looks like this.

The water will further discharge to Chlorination Chamber

The water is discharged to a Chlorination Chamber. Chlorination is one of many methods that can be used to disinfect water. This method was first used over a century ago, and is still used today. It is a chemical disinfection method that uses various types of chlorine or chlorine-containing substances for the oxidation and disinfection of what will be the potable water source.

Chlorination Chamber

 

And finally continued in Explanation 3.

Field Visit #3: Onsite Explanation 1

Bukit Indah Waste Water Treatment Plant is one of the Plant managed by Indah Water Konsortium (IWK). IWK is subsidiary company of Ministry of Finance, Malaysia. The plant was designed to serve 70,000 PE, now the level of service has reached about 69,000 PE.

Here is the location of Bukit Indah WWTP.

Location of Bukit Indah WWTP

Mr. Adha, first, brought the students to a ‘wet well’ where all the wastewater received from the service areas (residential and commercial areas surroundings). here is this well, there are two screens with mechanical device that filtered the the coarse grits come from the sewer line. Thus, only fine sediment will go for further process.

Here are few image of the wet well grit chamber.

Wet well Grit Chamber

Mr. Adha explains the functions and responds to student’s curiousity.

Students enthusiastically listen to Mr. Adha’s explanation

Can you imagine your waste means business? In fact, wastes are money. Here are some facts. Wongpanit is one of the largest company deal with recyclable garbage. For many people, garbage is unwanted stuff, but for Mike Wolfe and Frank Fritz, the American Pickers, junk is money.

We continued to observe aeration tank.

In 2 tanks of about 15x30x3m in size, in this aeration tank, wastewater were separated from fatty scum, the floated scums are then removed from the liquid part. The wastewater supplied with oxygen by using blower and diffuser, to increase BOD and remove unwanted substance such as iron.

Continued to other Onsite Explanation 2.

Field Visit #2: Implementation

We, 34 students plus 1 lecturer, successfully Wastewater Treatment Plant Bukit Indah managed by Indah Water Konsortium. The bus left UTM at 1:35pm and reached WTP at 2:15pm.

Here we are on board (on a UTM bus on the way to Bukit Indah via Skudai-Perling-Toll road-Bukit Indah.

On the way to Bukit Indah

We arrived at Bukit Indah WTP at 2:15pm and welcomed by Mr. Mohd Haidi and Mr. Adha Masnee, IWK Officer. We have a brief explanation on the WTP.

After having a brief explanation on WTI, the students were divided into two groups. First group was led by Mr. Haidi, and second group was led by Mr. Adha.

Continued in next part.