Design Report: Waterborne Sanitation System
Isiqalo Informal Settement
Cape Town
WSE3701 Assessment 2: Design Project
Name: Sihle Mkalipi
Student No: 18277071
Date: 16 July 2025
Lecturer: Ms P Roaphala
,Table of Contents
Executive Summary .............................................................................................................. 3
Introduction ........................................................................................................................... 4
Aim .................................................................................................................................... 4
Study Area Description.......................................................................................................... 5
Location............................................................................................................................. 5
Population and Layout ....................................................................................................... 5
Site Conditions .................................................................................................................. 5
Current Sanitation Issues .................................................................................................. 6
Literature Review .................................................................................................................. 7
1. Sanitation in Informal Settlements .............................................................................. 7
2. Challenges of Current Sanitation Solutions in Cape Town .......................................... 7
3. Sanitation Technologies .............................................................................................. 8
4. Design Standards and Guidelines .............................................................................. 8
System Selection and Justification ........................................................................................ 9
Considered Alternatives: .................................................................................................... 9
Selected System ................................................................................................................ 9
Risk Mitigation .................................................................................................................. 10
Hydraulic Design Calculations ............................................................................................. 11
Design Assumptions: ........................................................................................................ 11
Manhole Design and Spacing ............................................................................................ 16
Wastewater Treatment Design .............................................................................................. 17
Anaerobic Pond ................................................................................................................ 17
Facultative Pond ............................................................................................................... 18
Maturation Pond ............................................................................................................... 18
Environmental and Sustainable Considerations .................................................................. 20
Groundwater and Surface Water Protection ....................................................................... 20
Effluent Quality and Reuse Potential ............................................................................... 20
Energy and Maintenance Efficiency ................................................................................. 20
Climate Resilience ........................................................................................................... 20
Social Sustainability......................................................................................................... 21
System Performance ....................................................................................................... 21
Environmental Benefits.................................................................................................... 21
Implementation Recommendations ................................................................................. 21
Conclusion .......................................................................................................................... 22
References ......................................................................................................................... 23
1
,ANNEXTURE A: Isiqalo Informal Settlement Sewer Layout ..................................................... 24
ANNEXURE B: Isiqalo Informal Settlement Sewer Simulation Layout ...................................... 25
ANNEXURE C: Water Elevation Profile Node MH1 to O1 ......................................................... 26
ANNEXURE B: Water Elevation Profile Node MH7 to O1 ......................................................... 27
ANNEXURE C: Water Elevation Profile Node MH12 to O1 ....................................................... 28
ANNEXURE D: Water Elevation Profile Node MH21 to O1 ........................................................... 29
RUBRIC ................................................................................................................................ 30
List of Table
Table 1: Showing Sanitation Options comparing their advantages and disadvantages .............. 9
Table 2: Design Assumption according to the Red Book, Section K: Sanitation ................... 11
Table 3: Calculation for Simulation Layout ........................................................................... 14
Table 4: Calculation for Invert Levels and Depths for Simulation Layou .............................. 15
Table 5: Showiing Table K.19 from Red Book Section K: Sanitation .................................... 16
Table 6: Treatmeant Layout Summary................................................................................. 19
List of Figures
Figure 1:Aerial view of Isiqalo Informal Settlement, Cape Twon (Google Earth, 2025) .......... 5
Figure 2: Chemical Toilets provided by City of Cape Town in Isiqalo Informal Settlement ( .... 6
Figure 3:Bucket toilets lined up in for collection in Isqalo Informal Settlement (Google Earth,
2025) .................................................................................................................................... 7
Figure 4: Wastewater Treatment Process ........................................................................... 17
2
, Executive Summary
This report presents a comprehensive engineering design proposal for a sustainable
sanitation system tailored to the unique challenges of the Isiqalo Informal Settlement,
located near Mitchells Plain in Cape Town. The settlement, home to approximately
1,000 residents across 200 informal dwellings, faces critical sanitation deficiencies
due to the absence of permanent infrastructure and the inadequate maintenance of
temporary services such as chemical and bucket toilets. These conditions have
resulted in significant public health risks, environmental degradation, and social
inequality.
The purpose of this report is to develop a technically sound, environmentally
sustainable, and economically feasible sanitation solution that addresses the
immediate and long-term needs of the Isiqalo community. The design integrates key
principles from the Human Settlement Red Book and the Waterborne Sanitation
Design Guide by Van Vuuren & Van Dijk, ensuring compliance with South African
standards and best practices in sanitation engineering.
The proposed system comprises a simplified sewer network with strategically placed
inspection manholes and shallow-gradient pipelines, designed to accommodate the
settlement’s high-density, unstructured layout. The collected wastewater will be
conveyed to a decentralized treatment facility using waste stabilization ponds,
offering a low-maintenance, cost-effective solution with potential for effluent reuse.
The report details the design process, including site analysis, system selection,
hydraulic design calculations, layout planning, and environmental impact
considerations. It concludes with recommendations for phased implementation,
community engagement, and long-term operation and maintenance strategies. This
project aims to not only improve living conditions in Isiqalo but also serve as a
replicable model for informal settlements facing similar challenges across South
Africa.
3
Isiqalo Informal Settement
Cape Town
WSE3701 Assessment 2: Design Project
Name: Sihle Mkalipi
Student No: 18277071
Date: 16 July 2025
Lecturer: Ms P Roaphala
,Table of Contents
Executive Summary .............................................................................................................. 3
Introduction ........................................................................................................................... 4
Aim .................................................................................................................................... 4
Study Area Description.......................................................................................................... 5
Location............................................................................................................................. 5
Population and Layout ....................................................................................................... 5
Site Conditions .................................................................................................................. 5
Current Sanitation Issues .................................................................................................. 6
Literature Review .................................................................................................................. 7
1. Sanitation in Informal Settlements .............................................................................. 7
2. Challenges of Current Sanitation Solutions in Cape Town .......................................... 7
3. Sanitation Technologies .............................................................................................. 8
4. Design Standards and Guidelines .............................................................................. 8
System Selection and Justification ........................................................................................ 9
Considered Alternatives: .................................................................................................... 9
Selected System ................................................................................................................ 9
Risk Mitigation .................................................................................................................. 10
Hydraulic Design Calculations ............................................................................................. 11
Design Assumptions: ........................................................................................................ 11
Manhole Design and Spacing ............................................................................................ 16
Wastewater Treatment Design .............................................................................................. 17
Anaerobic Pond ................................................................................................................ 17
Facultative Pond ............................................................................................................... 18
Maturation Pond ............................................................................................................... 18
Environmental and Sustainable Considerations .................................................................. 20
Groundwater and Surface Water Protection ....................................................................... 20
Effluent Quality and Reuse Potential ............................................................................... 20
Energy and Maintenance Efficiency ................................................................................. 20
Climate Resilience ........................................................................................................... 20
Social Sustainability......................................................................................................... 21
System Performance ....................................................................................................... 21
Environmental Benefits.................................................................................................... 21
Implementation Recommendations ................................................................................. 21
Conclusion .......................................................................................................................... 22
References ......................................................................................................................... 23
1
,ANNEXTURE A: Isiqalo Informal Settlement Sewer Layout ..................................................... 24
ANNEXURE B: Isiqalo Informal Settlement Sewer Simulation Layout ...................................... 25
ANNEXURE C: Water Elevation Profile Node MH1 to O1 ......................................................... 26
ANNEXURE B: Water Elevation Profile Node MH7 to O1 ......................................................... 27
ANNEXURE C: Water Elevation Profile Node MH12 to O1 ....................................................... 28
ANNEXURE D: Water Elevation Profile Node MH21 to O1 ........................................................... 29
RUBRIC ................................................................................................................................ 30
List of Table
Table 1: Showing Sanitation Options comparing their advantages and disadvantages .............. 9
Table 2: Design Assumption according to the Red Book, Section K: Sanitation ................... 11
Table 3: Calculation for Simulation Layout ........................................................................... 14
Table 4: Calculation for Invert Levels and Depths for Simulation Layou .............................. 15
Table 5: Showiing Table K.19 from Red Book Section K: Sanitation .................................... 16
Table 6: Treatmeant Layout Summary................................................................................. 19
List of Figures
Figure 1:Aerial view of Isiqalo Informal Settlement, Cape Twon (Google Earth, 2025) .......... 5
Figure 2: Chemical Toilets provided by City of Cape Town in Isiqalo Informal Settlement ( .... 6
Figure 3:Bucket toilets lined up in for collection in Isqalo Informal Settlement (Google Earth,
2025) .................................................................................................................................... 7
Figure 4: Wastewater Treatment Process ........................................................................... 17
2
, Executive Summary
This report presents a comprehensive engineering design proposal for a sustainable
sanitation system tailored to the unique challenges of the Isiqalo Informal Settlement,
located near Mitchells Plain in Cape Town. The settlement, home to approximately
1,000 residents across 200 informal dwellings, faces critical sanitation deficiencies
due to the absence of permanent infrastructure and the inadequate maintenance of
temporary services such as chemical and bucket toilets. These conditions have
resulted in significant public health risks, environmental degradation, and social
inequality.
The purpose of this report is to develop a technically sound, environmentally
sustainable, and economically feasible sanitation solution that addresses the
immediate and long-term needs of the Isiqalo community. The design integrates key
principles from the Human Settlement Red Book and the Waterborne Sanitation
Design Guide by Van Vuuren & Van Dijk, ensuring compliance with South African
standards and best practices in sanitation engineering.
The proposed system comprises a simplified sewer network with strategically placed
inspection manholes and shallow-gradient pipelines, designed to accommodate the
settlement’s high-density, unstructured layout. The collected wastewater will be
conveyed to a decentralized treatment facility using waste stabilization ponds,
offering a low-maintenance, cost-effective solution with potential for effluent reuse.
The report details the design process, including site analysis, system selection,
hydraulic design calculations, layout planning, and environmental impact
considerations. It concludes with recommendations for phased implementation,
community engagement, and long-term operation and maintenance strategies. This
project aims to not only improve living conditions in Isiqalo but also serve as a
replicable model for informal settlements facing similar challenges across South
Africa.
3
