Construct the Wastewater Infrastructure

Learning Outcome

4.1 Source and mobilize construction materials and tools

4.2 Set out infrastructure

4.3 Construct wastewater infrastructure units

4.4 Do labour payments

4.5 Prepare and submit as built drawings

4.6 Prepare payment certificate

4.7 Prepare completion certificate

4.8 Observe site personal health and safety

Introduction to learning outcome

This learning outcome covers Constructional details of onsite sanitation facilities and

Construction plant and equipment. It also equips the learner with labour payment

knowledge.

Definition of key terms

Trickling filters – These are a wastewater treatment system made up of crushed rocks in a

tank of a depth of about 2 metres and a diameter of about 60 metres that is used to remove

organic pollutants.

Sedimentation tanks—These are part of a wastewater treatment system where waste

water is filled and allowed to settle for a while so as to remove suspended particles that are

in the wastewater.

Grit chambers—These are tanks that are long and narrow and are used to remove

inorganic solids from waste water by reducing the speed of the flowing wastewater.

and fine), Steel, Stones /blocks, Timber, Tape measure, hacksaws, and Pipe

wrenches, Levelling tools (e.g., hammer), and a Set of protective gear based on the bill

of quantities

A bill of quantities entails the construction materials, tools, labour and their costs. It also

includes the quantities required. it is usually prepared after specifications have been set and

the design of the infrastructure has been done.

It will be used as a guide to obtain the specific quantities of construction materials needed.

Sourcing of construction materials involves balancing between the cost of materials and

their quality.

Material sourcing for construction involves the following activities:

1. Deciding on possible suppliers.

Based on the materials that are required, you can choose a supplier for example a

hardware store or a wholesaler with the required materials.

2. Checking the availability of materials.

You could call the viable suppliers to check whether the required materials are in stock.

Also in this step you could confirm the quality of the materials in stock.

3. Requesting quotes from the suppliers.

This is done so as to find a supplier with the most economical price. The quote can be

obtained via email or by going to the supplier.

After obtaining the quotes a price comparison is done to decide the final supplier.

4.2 Set out infrastructure based on the engineering drawings.

Setting out infrastructure is a process of transferring an engineering drawing onto the

site/actual ground so as to establish the necessary structural parts. It enables construction

to be carried out as it has been planned.

Setting out is done by using the following methods:

a. Using the peg and rope method

b. By using a dumpy level.

The procedure for setting out is as follows:

i. The building line for the wastewater infrastructure is first set out.

ii. The baseline for the infrastructure is then set out.

iii. The first right angle to the baseline is set out next.

iv. The second right angle to the baseline is set out.

v. The final back line is set out.

vi. The set out for the infrastructure is then checked to confirm the measurements.

vii. Profiles are then set up on corners and ranging lines attached.

4.3 Construct wastewater infrastructure units (Screen, Grit chamber-horizontal,

aerated/spiral, Sedimentation tanks, Activated sludge chamber, Trickling filters,

Ponds, oxidation ditches, Aerated lagoons, Storm water drains, equalization tanks,

Sequential Batch Reactor, Rotating biological contactors, Oil and grease trap)

based on the design drawings

Waste water infrastructure units are the units that are systematically used to purify water

so that it can be recycled back.

Construction of these units is done in with reference to the engineering drawings and bill

of quantities on the site where they have been set out.4.4 Do labour payments based on the progress report and attendance.

A progress report is a report that details the activities that have been carried out, those that

have been completed, those that are in progress, any problems that may have been faced

and how the construction project is proceeding.

The progress report facilitates labour payments, called progress payments. These are partial

payments made to cover the amount of work that has been done at a particular stage or by

what percentage of work that has been done.

4.5 Prepare and submit as built drawings based on the actual construction.

As-built drawings are revised drawings that are prepared and submitted by the contractor

after the project has been completed.

They usually indicate all the adjustments made while building the project.

The method of preparing is built drawings is as follows:

1. Preparation of the as built drawings by the contractor.

The contractor incorporates all changes made to the original design in accordance

with official notes regarding such changes. The contractor is also supposed to visit

the site to ensure all the changes are reflected in the drawing.

After preparing the drawings, they are submitted to the Engineer overseeing the

construction.

2. Approval of the as built drawing by the engineer.

The engineer verifies the drawings with the official notes time to time according to

how much construction has been done?

They will also go to the site and check the drawings against the constructed

facilities.

If satisfied, the engineer will accept the drawings and keep a record of them in them

office.

4.6 Prepare a payment certificate based on the progress report.

A payment certificate in construction is a document that gives an account of the work that

has been completed. It is approved by the contractor.

They are issued either on a regular basis or when a project reaches a particular milestone.

Some types of payment certificates include certificate of non-completion, interim

certificate, practical completion certificate, and final certificate.

4.7 Prepare completion certificate based on the legal requirements.

A completion certificate is also called a final certificate. It is usually submitted when the

project has been completed successfully at the end of the contract. The construction has to

have met required specifications outlined by Building regulations stipulated by the Kenyan

Government.

4.8 Observe site personnel health and safety as per the OSH Act and site regulations.

OSH Act is a set of rules meant to ensure the safety and well-being of employees by

employers by protecting them from hazards.

These regulations help in the identification, reduction and elimination of hazards that are

related to construction work.

The employers and employees must adhere to the set standards of safety to avoid getting

injured due to the top four construction hazards, which include

1. Falls

2. Struck-By

3. Caught-In/Between

4. Electrocutions

Conclusion

This learning outcome covered Constructional details of onsite sanitation facilities and

Construction plant and equipment.

Written Assessment

1. Which of the following is not a waste water infrastructure unit?

a) Activated sludge chamber

b) Trickling filter

c) Pit latrine

d) Grease trap

2. Which one is not a type of payment certificate?

a) Final certificate

b) Certificate of non-completion

c) Independent certificate

d) Interim certificate.

3. One of the following better defines an as built drawing. Which one is it?

a) The drawing of the building before construction.

b) The revised drawing of the building after construction.

c) A sketch drawing

d) None of the above.

4. A completion certificate is also called?

a) Interim certificate

b) b) Project certificate

c) c) Final certificate

d) d) None of the above

5. What does OSH Act stand for and what does it entail?

6. Define a progress report.

7. Discuss 4 wastewater infrastructure units.

8. Write a short essay outlining the basic steps that are followed in material sourcing and

their significance.

9. Discuss what a payment certificate is and expound on the various types of payment

certificates.

Oral Assessment

Demonstrate various waste water infrastructure units.

Examine the steps followed while sourcing materials for construction?

Practical Assessment

Design an engineering drawing of a trickling filter and practice setting out its

infrastructure.

Oral Assessment

Mention the challenges faced in the process of designing the trickling filter.

What are the major steps followed while setting out infrastructure?