Parameters
Learning Outcome
6.1 Identify design Parameters to be calculated
6.2 Identify tools for parameter calculation
6.3 Calculate various wastewater infrastructure design
parameters
Calculate Wastewater Infrastructure Design
Parameters
Introduction to learning outcome
This learning outcome covers Sizing of the pipes, Hydraulic flow in pipes, Depth of flow,
Gradient, and Sizing of treatment units. Pipe sizing is a process in which various pipes are
made concerning its diameter. The difference in pipe sizes affects the pressure and the
velocities of the fluid flowing within the pipes. Narrow pipes result in higher velocities of
flow.
Definition of key terms
BOD: (biochemical oxygen demand). This is the quantity of oxygen dissolved required
by anaerobes to digest organic material in the water at a given temperature over a specified
duration of time.
TSS 🙁 total suspended solids). This is the dry mass of undissolved suspended particles in
a given water sample that can be trapped and filtered such as silt.
Gradient: This is the inclination nature of a slope (upward or downward)741
6.1 Identify design Parameters (Screening units, sedimentation tanks, grit chamber,
trickling filters, stabilization ponds, activated sludge system) to be calculated
based on the wastewater design manual.
There are many design parameters to be calculated based on the wastewater design manual.
They include;
Hydraulic load- wastewater influent expressed in per person per day.
Mass load-indicator of water quality and pollution level
BOD – (biochemical oxygen demand).
COD-chemical oxygen demand. The volume of suspended solids
6.2 Identify tools for parameter calculation (Theodolite, Dumpy level, GPS, Total
station, levelling staff, booking sheet, Soil sampler, Adequately equipped soil
mechanics labouratory, Flow Measuring structures, and devices, Stopwatch,
Questionnaires) based on the parameter to be calculated.
Tools used during the calculation of hydraulic load include; booking sheet, flow measuring
structures, and devices and a stopwatch. Tools used during the calculation of Mass load.
Mass load requires an adequately equipped soil mechanics lab to determine the pollution
level.
BOD is measured by BOD analyzers
Table 54: Tools used during the calculation of Mass load
Tool Name
Description
Theodolite
Measures horizontal and vertical angles
Dumpy level
Measures points on the same horizontal plane
GPS
Global positioning system
Booking sheet
Tabulation of survey data
Stopwatch
Performs accurate timing
Soil sampler
Analyze soil samples
Pipe diameter size is required to determine the discharge and area of discharge at a given
time to calculate the hydraulic load.
6.3 Calculate various wastewater infrastructure design parameters based on design
codes.
Written Assessment
1. Which of the following is not a design parameter in wastewater analysis?
a) Hydraulic load
b) Lateral wind load
c) suspended solids (TSS)
d) mass loading743
2. The indicator of the water pollution level is known as.
a) Mass load
b) Hydraulic load
c) BOD
d) COD
3. Which instrument measures horizontal and vertical angles?
a) Theodolite
b) Stopwatch
c) Dumpy level
d) Soil sampler
4. Discuss the following terms as used in the waste water analysis
a) Design parameter
b) Hydraulic load
c) Mass load
5. Calculate the hydraulic loading rate given: design flow is 12860 gallons per day, the area
is 19.2m2
6. Discuss four parameters of wastewater analysis
7. Describe how suspended solids are removed in wastewater?
8. Discuss the effects of the variation of BOD in wastewater.
9. Sizing the pipe to be small is a necessary evil. Elabourate.
Oral Assessment
What were your observations during the visit to the nearby water treatment plant?
What conclusions can be made?
Practical Assessment
Experiment to determine the content of parameters in wastewater.
Illustrate the direction of the flow of wastewater in various stages.