CODE REFERENCE SERIES ON-SITE SEWAGE SYSTEMS

Ahmed Sharaf, P. Eng

CONTAINS: BUILDING CODE ACT, 1992AND RELEVANT PORTIONS OF O. REG. 332/12

CODE REFERENCE SERIES

ON-SITESEWAGE SYSTEMS

ON-SITE SEWAGE SYSTEMS

i

INTRODUCTION

A significant percentage of the public rely on ground water as a source of drinking water either through community systems or through individual water wells. Therefore, protecting ground water from contamination and ensuring that it remains a safe source for domestic use is of utmost importance.

On-site sewage systems (septic systems) can be a major source of groundwater contamination and surface water degradation. Reversing this contamination/degradation can be difficult and costly. It is estimated that about 25% of households in Canada (and the U.S) are served by on-site sewage systems where sewage generated from these households is treated and discharged back into the environment through the system located within the same lot, or through a communal system. In both cases treatment occurs when sewage is pre-treated mostly in a septic tank then discharged to soil subsurface for final treatment and dispersal. Given the major role soil plays in this process, on-site sewage systems (septic systems) are sometimes referred to as soil-based systems. On-site sewage systems are viable and may be the only alternative for sewage treatment in areas without municipal sewers. Unlike metropolitan areas where sewage is collected and delivered to centralized wastewater treatment plants for treatment and disposal into a water body, on-site sewage systems treat the sewage at the same area where it has been generated.

It has been documented that sewage treatment through properly designed, constructed and managed on-site sewage systems are a viable, cost- effective, long-term option that meets public health and water quality goals. However, sewage systems have not been adequately taught in engineering schools. Unfortunately, engineering programs at most Canadian universities do not cover the concept and technology behind on-site wastewater treatment systems. This is in contrast to the field of centralized wastewater systems which has been the subject of more thorough research on its technical and organizational requirements.

This book may be considered an introductory textbook to soil-based treatment systems. It is hoped that the book will be complemented by detailed presentations and examples. Each chapter will be further developed into a separate module for continuing education. Modules will cover wastewater constituents, soil and soil treatment mechanisms, design and construction of different systems as well as field inspections of on-site systems. Continuing education, either to keep up with the development in this field or to maintain licenses or certification, is the key to raising awareness of this industry and gaining the trust of the public and regulatory authorities with regards to the specialized expertise of on-site sewage systems professionals.

Ahmed Sharaf, P.Eng.Toronto, Ontario, CanadaJanuary 12, 2013


1

TAB REFERENCE

PART 1

CHAPTER 1 Wastewater

CHAPTER 2 Site Evaluation and Soil Investigation

CHAPTER 3 Treatment Concept and Process Introduction

CHAPTER 4 Design and Construction

CHAPTER 5 Septic System Inspections

LIST OF TABLES, FIGURES, PHOTOS AND REFERENCES

PART 2

Introduction to the Ontario Building Code 2012

On-Site Sewage Systems in Ontario

BUILDING CODE ACT, 1992

RELEVANT PORTIONS OF O. REG. 332/12

DIVISION A Compliance, Objectives and Functional Statements

PART 1 Compliance and General

PART 2 Objectives

PART 3 Functional Statements

DIVISION B Acceptable Solutions

PART 1 General

PART 3 Fire Protection, Occupant Safety and Accessibility

PART 7 Plumbing

PART 8 Sewage Systems (with Commentary)

PART 11 Renovation

DIVISION C Administrative Provisions

PART 1 General

PART 2 Alternative Solutions, Disputes, Rulings and Interpretations

PART 3 Qualifications

PART 4 Transition, Amendments, Revocation and Commencement

APPENDIX

5


INTRODUCTION ...................................................................................................... 7

1.1 DOMESTIC WASTEWATER

1.1.1 Physical Characteristics ........................................................................... 7

1.1.2 Chemical Characteristics ......................................................................... 7

1.1.3 Biological Characteristics ......................................................................... 8

1.1.4 Level of Various Contaminants in Domestic Wastewater ........................ 8

1.2 NON-DOMESTIC WASTEWATER

1.2.1 Restaurants .............................................................................................10

1.2.2 Car Wash Facilities .................................................................................10

1.2.3 Laundromat Operations ..........................................................................11

1.2.4 Slaughterhouses .....................................................................................11

1.2.5 Recreational Vehicle Dumping Stations ..................................................11

1.2.6 Retirement and Nursing Homes .............................................................11

1.3 IMPACT OF SEWAGE ON PUBLIC HEALTH AND THE ENVIRONMENT

1.3.1 Impact on Public Health ..........................................................................13

1.3.2 Impact on the Environment ....................................................................15

1.4 WASTEWATER FLOW

1.4.1 Residential Occupancies .........................................................................16

1.4.2 Non-Residential Occupancies .................................................................16

1.4.3 Design Flows ..........................................................................................17

CHAPTER 1 WASTEWATER

23


2.1 SITE EVALUATION

2.1.1 Determination of Overall Site Suitability ................................................ 25

2.1.2 Physical Features and Subsurface Drainage .......................................... 25

2.2 SOILS AND SOIL INVESTIGATION

2.2.1 Soil Components ................................................................................... 26

2.2.2 Soil Profile and Patterns ......................................................................... 27

2.2.3 Soil Characteristics ................................................................................ 27

2.3 SOIL TEXTURE

2.3.1 Soil Texture Classification ...................................................................... 30

2.3.2 Soil Texture Determination .................................................................... 31

2.4 SOIL STRUCTURE

2.4.1 Soil Structure Determination .................................................................. 33

2.5 CONSISTENCY .............................................................................................. 37

2.6 COLOUR

2.6.1 Measuring Soil Colour using the Munsell System ................................. 38

2.7 SOIL DRAINAGE ............................................................................................ 40

2.8 TERMS USED TO DESCRIBE DRAINAGE THROUGH SOIL

2.8.1 Bulk Density ........................................................................................... 40

2.8.2 Clay Mineralogy ......................................................................................41

2.8.3 Permeability ............................................................................................41

2.8.4 Percolation Time .....................................................................................41

2.8.5 Hydraulic Conductivity ........................................................................... 44

2.9 UNIFIED SOIL CLASSIFICATION SYSTEMS ........................................... 45

2.10 EFFECTIVE SIZE AND UNIFORMITY COEFFICIENT ............................ 49

CHAPTER 2 SITE EVALUATION AND SOIL INVESTIGATION

51


INTRODUCTION ................................................................................................... 53

3.1 PRIMARY TREATMENT

3.1.1 Septic Tank ............................................................................................ 53

3.1.2 Septic Tank Design Consideration ......................................................... 55

3.1.3 Septic Tank Construction ....................................................................... 59

3.1.4 Operation and Maintenance .................................................................. 60

3.2 GREASE INTERCEPTOR .............................................................................. 60

3.3 OTHER PRE-TREATMENT SYSTEMS

3.3.1 Aerobic Treatment Units ........................................................................ 62

3.3.2 Attached Growth Systems .................................................................... 65

3.4 FINAL WASTEWATER TREATMENT IN SOIL

3.4.1 The First Treatment Zone – The Clogging Layer (Biomat) ..................... 68

3.4.2 The Second Treatment Zone – Unsaturated Soil Depth..........................71

3.5 MAIN CONTAMINANTS IN WASTEWATER AND THEIR TREATMENT PROCESS IN SOIL

3.5.1 Biochemical Oxygen Demand (BOD) and Total Suspended ...................... Soil (TSS) ............................................................................................... 72

3.5.2. Pathogen ................................................................................................ 73

3.6 PATHOGENIC ATTENUATION MECHANISM IN SOIL

3.6.1 Attenuation of Bacteria .......................................................................... 75

3.6.2 Attenuation of Viruses ........................................................................... 76

CHAPTER 3 TREATMENT CONCEPT AND PROCESS

52


3.7 NUTRIENTS

3.7.1 Phosphorus ............................................................................................ 78

3.7.2 Nitrogen ................................................................................................. 79

3.8 FACTORS AFFECTING THE TREATMENT............................................... EFFICIENCIES OF CONTAMINANTS IN SOIL ................................................ 80

APPENDIX 3-1 Pathogens in Wastewater And Outbreak Of Disease ................. 81

APPENDIX 3-2 Vertical Separation ...................................................................... 83

83


APPENDIX 3-2 VERTICAL SEPARATION

This document is a review of available scientific literature and a listing from fifteen other states prepared by by Selden Hall, October 1990, Office of Environmental Health and Safety, Washington State Department of Health. It has been reprinted with permission from the Department.

Table of Contents

Introduction/Summary ....................................................................................... 84

Definitions

1. Vertical Separation ................................................................................. 84

2. Saturated Flow ....................................................................................... 84

3. Unsaturated Flow ................................................................................... 84

4. Treatment of Sewage ............................................................................ 84

5. Significance ........................................................................................... 85

Review of Research Findings

1. Saturated Flow ....................................................................................... 86

2. Unsaturated Flow ................................................................................... 86

3. Amount of Vertical Separation Required for Microbial Removal ............ 87

4. Chemical Treatment Related to Vertical Separation ............................... 88

5. Vertical Separation Requirements in Various States .............................. 88

Summary and Conclusions ............................................................................... 90

Annotated Bibliography ..................................................................................... 90 Additional Reading .............................................................................................. 95

97


INTRODUCTION .................................................................................................... 99

4.1 OBJECTIVES AND PERFORMANCE EXPECTATIONS

4.1.1 Disease Prevention ................................................................................ 99

4.1.2 Environmental Protection ..................................................................... 100

4.1.3 Treatment Expectations ....................................................................... 100

4.2 BASIC COMPONENTS OF THE STANDARD SEWAGE SYSTEM

4.2.1 Septic Tank .......................................................................................... 102

4.2.2 Effluent Distribution System ................................................................ 104

4.2.3 Leaching Beds ......................................................................................110

4.3 DESIGN CONSIDERATIONS

4.3.1 Characterization of Soil and Wastewater ..............................................115

4.3.2 System Selection ..................................................................................115

4.3.3 Loading Rates .......................................................................................116

4.3.4 Vertical Separation ................................................................................118

4.3.5 Effluent Distribution .............................................................................120

4.3.6 Geometry, Configuration, Orientation and Placement: Trenches .............. versus Beds ..........................................................................................121

4.3.7 Mounding Analysis ...............................................................................123

CHAPTER 4 DESIGN AND CONSTRUCTION

98


4.4 CONSTRUCTION CONSIDERATIONS

4.4.1 General .................................................................................................125

4.4.2 Septic Tank Installation .........................................................................126

4.4.3 Leaching Bed Installation ......................................................................131

139


INTRODUCTION ...................................................................................................141

5.1 OVERVIEW AND REGULATORY BACKGROUND

5.1.1 Overview ..............................................................................................142

5.1.2 Regulatory Background .........................................................................142

5.1.3 Mandatory Maintenance Inspection Programs .................................... 143

5.2 SEPTIC SYSTEM MALFUNCTION AND FAILURE

5.2.1 System Malfunction ............................................................................. 146

5.2.2 System Failure ..................................................................................... 146

5.3 AVOIDING SYSTEM MALFUNCTIONS OR FAILURE .......................... 150

5.4 ONTARIO BUILDING CODE OPERATION AND ....................................... MAINTENANCE REQUIREMENTS ..................................................................152

5.5 SAFETY DURING SITE INSPECTION ..................................................... 154

5.6 COMPLIANCE INSPECTION - INSPECTION OF NEW SYSTEMS

5.6.1 Inspection Following the First Mandatory Notice ................................ 154

5.6.2 Inspection Following the Second Mandatory Notice ............................155

5.7 INSPECTIONS OF EXISTING SYSTEMS

5.7.1 Maintenance Inspection ...................................................................... 160

5.7.2 Data Collection......................................................................................161

5.7.3 General Observation of Site Conditions ................................................161

5.7.4 Tools Used in Site Inspection .............................................................. 163

5.7.5 Locating and Inspecting the Septic System Components ................... 166

5.7.6 Functional Inspection ............................................................................177

5.7.7 Inspecting Other Treatment Units ........................................................181

5.7.8 Inspecting Other Classes of Sewage Systems ................................... 182

CHAPTER 5 SEPTIC SYSTEM INSPECTIONS

140


APPENDIX

APPENDIX 5-1 Examples of Failures ................................................................. 184

APPENDIX 5-2 Renovation and Restoration of Sewage Systems ..................... 199

APPENDIX 5-3 Buying or Selling a Home with a Septic System ....................... 204

APPENDIX 5-4 Homeowner’s Guide to the Service Contracts ......................... 208

APPENDIX 5-5 Guide to Proper Abandonment of Unused Septic Tanks............211

APPENDIX 5-6 Sample Inspection Report .........................................................214

183


APPENDIX

APPENDIX 5-1 Examples of Failures ................................................................. 184

APPENDIX 5-2 Renovation and Restoration of Sewage Systems ..................... 199

APPENDIX 5-3 Buying or Selling a Home with a Septic System ....................... 204

APPENDIX 5-4 Homeowner’s Guide to the Service Contracts ......................... 208

APPENDIX 5-5 Guide to Proper Abandonment of Unused Septic Tanks............211

APPENDIX 5-6 Sample Inspection Report .........................................................214

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LIST OF TABLES

1.1 Raw Sewage Characteristics1.2 Septic Tank Effluent Characteristics1.3 The Main Pollutants in Wastewater and the Concerns Associated with their

Presence1.4 Pathogens in Wastewater and their Related Diseases1.5 Important Protozoan Pathogens and their Related Diseases1.6 Sewage sources and their percentage of the daily flow in a typical residence1.7 Ontario Building Code Residential Occupancy (Table 8.2.1.3.)2.1 Soil Texture Properties2.2 Soil Structure Shape Abbreviation2.3 Structure Size2.4 Soil Size Classification2.5 Sand Classification2.6 Soil Colour and Soil Drainage2.7 Approximate Relationship of Soil Types to Permeability and Percolation Rate2.8 Typical Hydraulic Conductivity Values for Various Types of Soils2.9 USCS Symbol Chart2.10 USCS Soil Groups2.11 Characteristics of USCS Soil Groups Pertaining to Permeability2.12 Differences in Particle Sizes between USDA and USCS3.1 Removal of Pollutants in Septic Tank3.2 Bacterial Pathogens and their Related Diseases3.3 Viral Pathogens and Their Related Diseases

LIST OF FIGURES

2.1 Soil Composition2.2 Soil Profile Showing Different Soil Horizons2.3 Soil Texture Triangle2.4 Types of Soil Structure2.5 Water Movement through Granular, Prismatic, Blocky, and Platy Structure2.6 Relative Proportions of Sand, Silt, and Clay Particles2.7 Munsell Colour System2.8 Flow Down Hill through a Layer of Soil2.9 Unified Soil Classification System3.1 On-site Sewage System Treatment Mechanism3.2 Septic Tank Components3.3 Cross Section of Two-Compartment Septic Tank3.4 Schematic of a Grease Interceptor3.5 Cross-Section in Two-Compartment Grease Trap3.6 Example of ATU Design3.7 Schematic of Wetland4.1 Sewage Generation, Treatment and Disposal4.2 Schematic of the On-Site Sewage System Showing the Components of a

Conventional System4.3 Typical Septic Tank4.4 Typical Pump and Pump Tank4.5 Typical Siphon4.6 Typical Pressure Distribution System

LIST OF TABLES, FIGURES, PHOTOS AND REFERENCES

224


4.7 Pathway of Subsoil Re-Aeration in a Typical Absorption Trench System4.8 Pathway of Subsoil Re-Aeration in a Bed-Type System4.9 Typical Trench-Type System4.10 Typical Cross-section of a Trench4.11 Vertical Separation4.12 System Installation Perpendicular to Site Slope4.13 Groundwater Mounding4.14 The Effect of Spreading Trenches on Reducing Mounding4.15 Deflection in the Pipe Connecting Building Sewer to the Septic Tank

LIST OF PHOTOS

2.1 Different Types of Soil Colours3.1 Inlet Tee3.2 Outlet Tee3.3 Effluent Filter at the Outlet of the Septic Tank3.4 Leveling the Base of the Septic Tank3.5 Concrete Three-Compartment Grease Interceptor3.6 Peat Filter3.7 Degradation of surface water caused by excess discharge of nutrients4.1 Distribution Box4.2 Distribution Pipe4.3 Polystyrene Wrapped Pipe4.4 Leaching Chamber4.5 Chamber Installation in Lieu of Gravel and Distribution Pipe4.6 Preparing the Connection between the Building Drain and the Septic Tank4.7 Fully Excavated Soil under the Pipe Connecting the Building Sewer to the

Septic Tank4.8 Sealing the Inlet and Outlet Pipes of the Septic Tank4.9 Leveling the bottom of the tank hole4.10 Septic Tank Being Lowered in the Hole4.11 The Septic Tank Placed in the Hole Ready to be Backfilled4.12 Unanchored Plastic Tank Deformed by Uplifting Pressure4.13 System Failure Due to Heavy Traffic4.14 Protecting Trench Bottom4.15 Septic Stone Placed Into the Bottom of the Raised Absorption Trench4.16 Distribution Pipe Installed in Septic Stone before Backfill4.17 Synthetic Drainage Fabric Covering the Septic Stone4.18 Chambers Assembled On-Site4.19 Chamber Backfilling4.20 Chamber Installation in Lieu of Gravel and Pipe5.1 Grease Accumulation in the Septic Tank5.2 Shallow Buried Trench System Failure5.3 Main Components of the Septic System Installed5.4 Septic Tank Inlet Pipe Sealing5.5 Stone Layer of Raised Absorption Trench5.6 Insulated Probe and Metal Detector5.7 Flushable Transmitters5.8 Sewer Camera or Drain Video Cameras5.9 Pipe and Cable Locator5.10 Different Types of Shovels5.11 Exposing the Top of the Septic Tank5.12 Locating the Septic Tank5.13 Damaged Access Cover5.14 Failed Septic Tank

225


5.15 Mirror on a Stick Used For Septic Tank Inspection5.16 Plugged Inlet of the Septic Tank Baffle5.17 Locating the Distribution Box Using Probe Bar5.18 Deteriorated Distribution Pipe5.19 Clearly Visible Absorption Trenches5.20 Evidence of Sewage Blockage5.21 Breakout of Sewage at Ground Surface5.22 Malfunctioning Siphon5.23 Dye Test5.24 Sample Collection from Sewage Breakout5.25 Dye Test Showing Effluent Leakage/Breakout

PHOTOS IN APPENDIX 5-1

A.1 Septic Tank ErosionA.2 Rusted Steel Septic TankA.3 Failed Septic Tank Resulted From Accumulation of GreaseA.4 Backup of Sewage in the Septic Tank Causing Breakout of Sewage A.5 Damaged Access Cover by Lawn MowerA.6 Cracked Concrete Septic Tank LidA.7 Plugged Septic Tank Inlet BaffleA.8 Collapsed Septic Tank Due to the Construction of a Driveway on Top of TankA.9 Septic Tank Lid Pushed up by Tree RootsA.10 Damaged Pressurized line Inside the Pump ChamberA.11 Poor Electric InstallationsA.12 Siphon Used to Dose the Effluent to the Leaching BedA.13 Plugged Effluent FilterA.14 Effluent Filter After CleaningA.15 Distribution Pipe Clogged by BiomatA.16 Completely Clogged Distribution PipeA.17 Cracked ChamberA.18 Damaged Septic Tank Leading to System FailureA.19 Obvious Sign of a System Failure Surface Breakout of SewageA.20 Illegal Connection to a DitchA.21 Sewage System Failure Due to Installation in Slowly Permeable SoilA.22 System Failure Due to Deep Installation

LIST OF REFERENCES

1. EPA Onsite Wastewater Treatment System Manual, 2002, EPA/625/R-00/08 2. Crites and Tchobanoglous, Small and Decentralized Wastewater Management

Systems, McGraw-Hill, 19983. U.S. Department of Agriculture (USDA), National Soil Survey Center4. West Virginia Department of Health – Manual of Environmental Health

Procedure5. US EPA Design Manual “Onsite Wastewater Treatment and Disposal Systems

19806. US EPA Onsite Wastewater Treatment Systems Manual7. Washington State Department of Health Wastewater Management Publications8. Technical Manual for Approving Authorities 1982, Ontario Ministry of the

Environment9. Design Manual, Subsurface Disposal Systems for Households and Small

Commercial Buildings, State of Connecticut, Department of Public Health, July 1998

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10. Dr. Randall J. Miles, Department of Soil, Environmental and Atmospheric Sciences, University of Missouri

11. (1) Gerba et al., (1975)12. (2) Pekdeger, (1984)13. (3) Tchobanoglous and Burton, 199114. (4) Pekdeger, 1984; Tchobanoglous and Burton, 199115. (5) Canter and Knox, 198516. (6) Anderson et al., 1994; 17. (6) Ayres Associates, 1993,18. (6) Bouma et al., 1972; 19. (6) McGauhey and Krone, 196720. (7) University of Wisconsin, 197821. (8) Ziebell et al., 197522. (9) Berg, 197323. (10) (Dunbar, 1908; Crites and Tchobanoglous, 1997; Hazen, 1904)24. (11) (Ludwig, 1950).25. Anderson, et al.,1981;26. Otis, R.J., 1984; 27. Siegrist, et al.,1984 and b; Siegrist, 198728. Tyler and Converse, 1989; 29. Jensen and Siegrist, 1991; 30. Tyler and Converse, 1994; Loudon, et al.,1998;31. Loudon, 1999; Matejcek et al.,2000; 32. Erlsten and Bloomquist, 2001; Tyler, 200133. Hain and O’Brien, 1979; 34. Jansons et al., 1989;35. Schaub and Sorber, 1977; 36. Vaughn and Landry, 1980; 37. Vaughn et al., 1981; 1982, 198338. Wellings et al., 1975.39. David Venhuizen,40. Bicki et al., 1984; 41. EPA Onsite Wastewater Treatment and Disposal Systems, 198042. State of Connecticut, Design Manual, Subsurface Sewage Disposal Systems for

Households and small Commercial Buildings, 1988 43. New Mexico Department of Environment (NMDE), Liquid Waste Program:

Homeowner’s Guide Installing a Septic Tank and Drainfield 44. Ontario Ministry of Environment and Energy, On-Site Sewage Disposal

Systems, 199745. Iowa Onsite Sewage Design and Reference Manual, 200346. Bitton, G, and C.P.Gerba. Groundwater Pollution Microbiology. New York: John

Wiley & Sons, 1984. Print.47. C.P.Gerba. C. Wallis. J.L. Melnick. Journal of the Irrigation and Drainage Division

101 (1975): 157. Print.48. Meinhardt, P.C. Casemore, D.P. Miller, K.B. “Epidemiologic Aspects of Human

Cryptosporidiosis and the Role of Waterborne Transmission”. Epidemiologic Reviews 18(2) (1996):118.

49. M. James Riordan and Anne Sherman Jett. Septic System Checkup: The Rhode Island Handbook for Inspection. Rhode Island, Department of Environmental Management, Office of Water Resources, 2002. Web. No date of access.

50. “Septic Systems - Operations & Maintenance”. New York State Department of Health. n.p. n.d. Web. No date of access provided.

51. Bruce J. Lesikar, Courtney O’Neill, Nancy Deal, George Loomis, David Gustafson, and David Lindbo. “Homeowner’s Guide to Evaluating Service Contracts”. Texas Cooperative Extension: The Texas A&M University System B-6171 7-05 Web. No date of access provided.

227


52. “Protocol for Onsite Sewage System Abandonment”. Indiana State Department of Health. June 12, 2002. State of Indiana IN.gov. Web. No date of access provided.

53. “Buying or Selling a Home with an Onsite Wastewater System”, Pipeline. 22.1(2011).

54. “Renovation/ Restoration of Subsurface Wastewater Infiltration Systems”. EPA Fact Sheet #10. Environmental Protection Agency. Nd. Web. No date of access provided. (Link to this item is broken).

55. Ahmed Sharaf, P. Eng., On-site Sewage Systems Code and Guidelines 200656. Bitton, G, and C.P. Gerba. Groundwater Pollution Microbiology. New York: John

Wiley & Sons, 1984. Print.57. C.P. Gerba. C. Wallis. J.L. Melnick. “No article title and article is not available

online”. Journal of the Irrigation and Drainage Division 101 (1975): 157. Print.58. Meinhardt, P.C. Casemore, D.P. Miller, K.B. “Epidemiologic Aspects of Human

Cryptosporidiosis and the Role of Waterborne Transmission”. Epidemiologic Reviews 18(2) (1996):118.

59. M. James Riordan and Anne Sherman Jett. Septic System Checkup: The Rhode Island Handbook for Inspection. Rhode Island Department of Environmental Management, Office of Water Resources, 2002. Web.

60. M. James Riordan and Anne Sherman Jett. Septic System Checkup: The Rhode Island Handbook for Inspection. Rhode Island Department of Environmental Management, Office of Water Resources, 2002. Web.

61. “Septic Systems - Operations & Maintenance”. New York State Department of Health. n.p. n.d. Web.

62. Bruce J. Lesikar, Courtney O’Neill, Nancy Deal, George Loomis, David Gustafson, and David Lindbo. “Homeowner’s Guide to Evaluating Service Contracts”. Texas Cooperative Extension: The Texas A&M University System B-6171 7-05 Web.

63. “Protocol for On-site Sewage System Abandonment”. Indiana State Department of Health. June 12, 2002. State of Indiana IN.gov. Web.

64. “Buying or Selling a Home with an On-site Wastewater System”, Pipeline. 22.1(2011). Web.

65. “Renovation/ Restoration of Subsurface Wastewater Infiltration Systems”. EPA Fact Sheet # 10. Environmental Protection Agency. Nd. Web.

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PART 2 TAB REFERENCE

Introduction to the Ontario Building Code 2012

On-Site Sewage Systems in Ontario

Building Code Act, 1992

Relevant portions of O. Reg. 332/12

DIVISION A Compliance, Objectives and Functional Statements

PART 1 Compliance and General

PART 2 Objectives

PART 3 Functional Statements

DIVISION B Acceptable Solutions

PART 1 General

PART 3 Fire Protection, Occupant Safety and Accessibility

PART 7 Plumbing

PART 8 Sewage Systems (with commentary)

PART 11 Renovation

DIVISION C Administrative Provisions

PART 1 General

PART 2 Alternative Solutions, Disputes, Rulings and Interpretations

PART 3 Qualifications

PART 4 Transition, Amendments, Revocation and Commencement

Appendix

233


Division A Objectives and Functional Statements ................................................ 235

Division B Acceptable Solutions ........................................................................... 236

Division C Administrative Provisions ..................................................................... 236

Intent of This Guide ................................................................................................ 236

INTRODUCTION TO ONTARIO BUILDING CODE 2012

235


In 2006, the government of Ontario published the Building Code in an “objective based” format. It is consistent with the 2005 model national codes and is the first regulation in Ontario to adopt this format. Under the new format, the Code still contains specific technical requirements which may be prescriptive or performance based. However, these requirements are now re-defined as acceptable solutions. Each requirement is related to one or more objectives consistent with the purposes behind the Code - public health and safety, conservation and environmental integrity, fire protection, structure sufficiency, and barrier-free accessibility. The new format also describes, through the functional statements, what the design and construction of the sewage system (building) must do to achieve these objectives. The Building Code was further amended in 2012.

With the continuation of this new format, it is hoped that there will be more consistency in the application of the Code. It is also hoped that the new format will encourage innovation in design and construction that would result in new solutions being added to the current ones.

The new Code is divided into three divisions:

Division A - contains the objectives and the functional statements

Division B - contains acceptable solutions

Division C - contains administration provisions

The following is an overview of the structure of the new code format.

Division A Objectives and Functional Statements

Under the objective based format, each technical requirement is linked to an objective, or objectives and functional statements. The objectives describe the overall goal the requirement is intended to achieve and are written in a format that describe the undesirable situations and their consequences, which the Code aims to avoid happening. Functional statements describe the design and construction conditions that help satisfy these objectives.

Both the objectives and functional statements are entirely qualitative in nature and are not intended to be used on their own in the design and approval process. The basic thinking behind each requirement is explained in the intent statements. The intent statements explain how the specific requirement helps to achieve the objectives and functional statement attributed to the requirement. They should help Code users to understand the reason behind Code requirements and develop alternative solutions to achieve the identified objectives.

INTRODUCTION TO ONTARIO BUILDING CODE 2012

236


Division B Acceptable Solutions

Division B contains most of the provisions from the 1997 Building Code in addition to the changes or additions resulting from the normal updating process. These technical requirements are now considered acceptable solutions. Part 8 of the Building Code contains the technical requirements related to sewage systems. Following the “solutions” given in Part 8 in the design and construction of a sewage system will result in a system that provides the minimum level of performance required by the code and is deemed to meet the objectives and functional statements listed in Division A.

Division C Administrative Provisions

Division C contains several administrative provisions formerly found in Part 2 of the 1995 Code. These provisions include requirements related to professional design requirements, permits and inspections, Building Code Commission, the Building Materials Evaluation Commission, Minister’s Rulings, Minister’s Interpretations and qualifications.

Intent of This Guide

This guide is intended to assist Code users by providing explanations of the purpose of each requirement and the scope within which these requirements were developed. The guide deals only with the Code provisions pertinent to sewage systems.The guide provides the design and construction requirements stipulated in Part 8 as well as the intent statements associated with each requirement. The guide also includes explanatory notes, figures and appendixes to provide additional information in particular areas that could be of interest to Code users.

It should be noted that the objectives and functional statements in the Code were expressed in terms of minimizing potential risk that may result from the design, construction and operation and maintenance of the sewage system. This is in recognition that it may not be possible to totally eliminate all risk; therefore, the wording used in the objectives and functional statements include phrases such as “to limit the probability” and “unacceptable risk”. They describe the undesirable situations and consequences the specific requirement is aimed to avoid.

The intent statements are not considered part of the Code; rather they are meant to serve explanatory purposes. In writing the intent statements in this guide, a great effort was made to adhere to the format used in the Code for the objectives and functional statements except where it was felt that more explanation of the basic thinking behind the requirement would be more beneficial. In such cases, the intent is given also in a direct way to describe the desirable situation the requirement is intended to achieve rather than the undesirable situation it meant to avoid. Therefore, what may appear as a repetition of the intent attributed to some requirements is in fact an endeavour to provide more clarity to the reason behind the requirement. It was felt that this may better serve the purpose behind providing the intent statements.

B8-3

DIVISION B 8.1.3.1.ON-SITE SEWAGE SYSTEMS

Section 8.1. General

8.1.1. Scope

8.1.1.1. Scope (1) The scope of this Part shall be as described in Subsection 1.1.2. of Division A.

8.1.1.2. Definitions (1) In this Part,Soil means in-situ, naturally occurring, unconsolidated

mineral or organic material, at the earth’s surface that is at least 100 mm thick and capable of supporting plant growth, and includes material compacted or cemented by soil forming processes, but does not include displaced materials such as gravel dumps, mine spoils, or like deposits.

8.1.2. Application

8.1.2.1. Classification of Systems (1) All sewage systems shall be classed as one of the following: (a) Class 1 — a chemical toilet, an incinerating toilet, a recirculating toilet, a self-contained portable toilet and all forms of privy including a portable privy, an earth pit privy, a pail privy, a privy vault and a composting toilet system, (b) Class 2 — a greywater system, (c) Class 3 — a cesspool, (d) Class 4 — a leaching bed system, or (e) Class 5 — a system that requires or uses a holding tank for the retention of hauled sewage at the site where it is produced prior to its collection by a hauled sewage system.

8.1.2.2. Operation and Maintenance (1) Operation and maintenance of sewage systems shall comply with Section 8.9.

8.1.3. Limitations

8.1.3.1. Discharge (1) Except as provided in Sentences (2) to (6), the sewage system shall be designed and constructed to receive only sanitary sewage of domestic origin.

NOTE• The Ministry of Municipal Affairs and Housing has not

yet published the objectives and functional statements related to the new sewage systems requirements introduced in 2012 Building Cod; therefore, they are not included in this book at this time. The author, however, developed intent statements to most of these requirements based on his own knowledge, experience and professional opinion. When it was uneasy for the author to provide the intent for some requirements, he provided comments and recommendation instead.

Sentence 8.1.2.1.(1)See Appendix for details of sewage systems covered under the Building Code

Sentence 8.1.3.1.(1)Objectives: OE, OH5Functional Statements: F81, F110, F111Intent:

• To limit the probability that the sewage system will malfunction or fail which could occur if the system receives sewage of type and characteristics that are not suitable for treatment in an onsite sewage system, and

• To limit the probability that the water resources will be contaminated which could occur if the sewage system receives sewage of type and characteristics that are beyond its capabilities to treated and safely discharge the treated effluent into the receiving environment.

B8-4

DIVISION B8.1.3.1. ON-SITE SEWAGE SYSTEMS

(2) Where laundry waste is not more than 20% of the total daily design sanitary sewage flow, it may discharge to a sewage system.

(3) Where industrial process waste water is treated to the contaminant levels found in domestic sanitary sewage, it may discharge to a leaching bed provided the treatment unit and sewage system are designed in accordance with good engineering practice.

(4) Where kitchen waste water from a restaurant has passed through an operating grease interceptor, it may discharge to a leaching bed provided the sewage system has been designed in accordance with good engineering practice.

(5) Waste water from a kitchen equipped with a garbage grinder may be directed to the sewage system provided the system has been designed to accept such waste water.

(6) Water softener and iron filter discharge may be directed to the sewage system provided the system has been designed to accept such discharges.

Sentence 8.1.3.1.(2)Intent:

• To limit the probability of system malfunction/failure which could occur if the system receives high concentrations of contaminants that are beyond the system’s capability of treatment

• To limit the probability of hydraulic failure of the system which could occur if the infiltrative surface is blocked by the formation of biomat layer that would resist the percolation of effluent into the soil

• To allow for the use of small Laundromats in malls or commercial plazas in rural areas where the volume of laundry waste compared to the total wastewater volume directed to the system is unlikely to impact on the performance of the system


• To limit the probability that the sewage system will fail which could occur if the system receives sewage of type and characteristics that are beyond its capability to safely treat an disperse the treated effluent to the nature environment, and

• To allow for the use of a sewage systems to service industrial or commercial establishments


• To allow for the use of sewage systems to service commercial restaurants without affecting the functionality of the system,

• To limit the probability that the system will fail which could occur if the sewage system receives sewage of higher level of contaminants (particularly fats, oil and grease) than those found in domestic sewage, and

• To ensure that the sewage system is designed in consideration of the volume and composition of the wastewater directed to the system


• To allow for the use of this device without affecting the functionality of the system,

• To limit the probability that the sewage system will be designed without proper consideration of the characteristics of the wastewater generated from a kitchen equipped with this device, and

• To guard against a premature failure of the leaching bed which could occur when excessive solids generated by this device accumulate in the septic tank and potentially pass over to the leaching bed blocking the infiltrative surface


• To allow for the use of these devices while ensuring that the discharge from the filter is accounted for in the design of the septic tank and the leaching bed such that the performance of these components and the whole system is not negatively affected by their use

B8-5

DIVISION B 8.2.1.2.ON-SITE SEWAGE SYSTEMS

(7) Storm sewage shall not be discharged into a sewage system.

(8) The interceptor required in Sentence (4) shall, (a) have a minimum flow rate as required by Sentence 7.4.4.3.(8) using a 60 second drain down time, and (b) conform to, (i) CAN/CSA-B481.1, “Testing and Rating of

Grease Interceptors Using Lard”, or (ii) CAN/CSA-B481.2, “Testing and Rating of

Grease Interceptors Using Oil”.

Section 8.2. Design Standards

8.2.1. General Requirements

8.2.1.1. Scope (1) This Subsection applies to the design of sewage systems.

8.2.1.2. Site Evaluation (1) A site evaluation shall be conducted on every site where a new or replacement sewage system is to be installed.

(2) The percolation time shall be determined by, (a) conducting percolation tests, or (b) classifying the soil according to one of the following methods, (i) the Unified Soil Classification System

as described in MMAH Supplementary Standard SB-6, “Percolation Time and Soil Descriptions”, or

(ii) the Soil Texture Classification as described in Chapter 3 of USDA, “Soil Survey Manual”.

Sentence 8.1.3.1.(7)Objectives: OE, OH5Functional Statements: F81, F110, F111Intent:

• To guard against overloading the system with a large volume of storm water not accounted for in the design which could lead to:

o upsetting the quiescent conditions inside the septic tank and impeding the settling process causing solids to pass to the leaching bed clogging the infiltrative surface, and

o overwhelming the soil component with a high volume of storm sewage that exceeds its capacity to absorb, treat and discharge the effluent in a safe manner which could lead to a breakout of sewage and/or inadequate treatment of effluent causing contamination of water resources

Sentence 8.1.3.1.(8)Objectives: OE, OH5 Functional Statements: F81, F111Intent:

• To limit the probability that the interceptor will not have the capability to adequately retain fat, oil and grease which could occur if the interceptor is not designed in accordance with the requirements of a recognizable standard which could lead to the blockage of the infiltrative surface and a premature system failure.

Sentence 8.2.1.2.(1)Objectives: OE, OH5 Functional Statements: F110, F111, F112Intent:

• To determine the overall site suitability to accommodate a properly functioning sewage system,

• To identify any site or soil limitation,

• To determine the most suitable system to service the building and overcome site or soil limitations if any,

Sentence 8.2.1.2.(2)Objectives: OE, OH5 Functional Statements: F81, F111Intent:

• To provide for an acceptable measure to determine soil characteristics, and

• To limit the probability that the percolation time will be incorrectly estimated which could lead to system failure.

B8-6

DIVISION B8.2.1.3. ON-SITE SEWAGE SYSTEMS

(3) Where the percolation time is determined by a percolation test, there shall be a minimum of 3 locations selected, suitably spaced to accurately evaluate the leaching bed area, with the highest percolation time of the tests being used.

8.2.1.3. Sewage System Design Flows (1) For residential occupancies, the total daily design sanitary sewage flow shall be at least the value in Column 2 as determined from Table 8.2.1.3.A.

(2) For all other occupancies, the total daily design sanitary sewage flow shall be at least the value in Column 2 as determined from Table 8.2.1.3.B.

(3) Where a building contains more than one establishment, the total daily design sanitary sewage flow shall be the sum of the total daily design sanitary sewage flow for each establishment.

(4) Where an occupancy is not listed in Table 8.2.1.3.B., the highest of metered flow data from at least 3 similar establishments shall be acceptable for determining the total daily design sanitary sewage flow.

Sentence 8.2.1.2.(3)Objectives: OE, OH5Functional Statements: F81, F111 Intent:

• To limit the probability that the system will malfunction or fail which could occur if the system is designed and constructed based on a percolation time that does not reasonably reflect the permeability of the soil, and

• To limit the probability that the percolation time used in the design does not reflect the soil permeability over the entire leaching bed area.


• To limit the probability that the system will be designed without proper consideration of the maximum potential use of the occupancy, and

• To provide for the conditions to permit the system to receive the maximum potential volume that may be generated from the occupancy over 24 hours period without hydraulic failure


Same as Sentence 8.2.1.3.(1)


• To limit the probability that the system will malfunction or fail which could occur if the system is designed and constructed without consideration of the maximum potential use of all the establishments within the building, and

• To ensure that the daily flow figures used in the design incorporate all the sewage flows generated from all occupancies serviced by the sewage system.


• To ensure that the sewage flow figures used in the design of the system reasonably reflect the volume expected to be generated from the establishment, and

• To limit the probability that any future repairs or replacement of the system or any of its components be impeded by insufficient clearances.

See Appendix A for explanation and example of total daily design sanitary sewage flow calculations


APP-3

APPENDIX A Sewage Systems Covered Under Part 8 ........................................... of the Building Code ................................................................ APP-5

APPENDIX B Explanatory Notes ....................................................................APP-7

APPENDIX C Absorption Trench and Filter Bed Construction and .......................... Various Soil Conditions ...........................................................APP-13

APPENDIX D Type B Dispersal Bed Explanatory Note ............................... APP-23

APPENDIX E Loading Rates for Type B Dispersal Beds ............................. APP-27

APPENDIX

CODE REFERENCE SERIES ON-SITE SEWAGE SYSTEMS

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