Massachusetts Public Health Inspector Training Wastewater Certificate Program (MA PHIT WW) Session 3: Site Evaluation and Selection 1 MA PHIT- Wastewater Certificate Program, Session 3

After completing this session, you will be able to:  List design considerations for site evaluation and selection for onsite systems  Discuss safety precautions in the field  Describe requirements for deep observation holes and percolation tests  Explain how to witness and document a percolation test  Explain how to determine soils layers and seasonal high groundwater levels Learning Objectives 2 MA PHIT- Wastewater Certificate Program, Session 3

A conventional septic system has  a septic tank,  a distribution box, and  a soil absorption system (SAS) Site Evaluation 3 MA PHIT- Wastewater Certificate Program, Session 3

Site Evaluation Criteria 1. Location and position (including topography and condition) 2. Setbacks 3. Soil classification and permeability (deep hole and percolation tests) 4. Estimated seasonal high groundwater 4 MA PHIT- Wastewater Certificate Program, Session 3

Video Play these videos Preliminary research to be performed in office 5 MA PHIT- Wastewater Certificate Program, Session 3 Necessary Tools for Site Evaluation

1. Location and Position Key question:  Where do we locate the onsite system components?  For septic tanks, what should we consider?  For the SAS what should we consider? 6 MA PHIT- Wastewater Certificate Program, Session 3

1. Location and Position 7 MA PHIT- Wastewater Certificate Program, Session 3

Video Play this video Site view and assessment of site constraints 8 MA PHIT- Wastewater Certificate Program, Session 3

2. Setbacks 9 MA PHIT- Wastewater Certificate Program, Session 3

2. Setbacks Why? 10 MA PHIT- Wastewater Certificate Program, Session 3

3. Soil Classification and Permeability Deep Observation Holes and Percolation Tests  Who can conduct the tests?  Who can witness and document the tests?  What is the purpose of the deep observation holes?  What is the purpose of a percolation test? True/False: the BOH must witness perc tests and deep holes. 11 MA PHIT- Wastewater Certificate Program, Session 3

Videos Play these videos Safety during soil testing 12 MA PHIT- Wastewater Certificate Program, Session 3

 What are potential hazards? Safety First 13 MA PHIT- Wastewater Certificate Program, Session 3

 Know your limits  Be cautious around big equipment  Know confined entry procedures  Use DigSafe  Go with your “gut” Safety First 14 MA PHIT- Wastewater Certificate Program, Session 3

Protective Measures  Develop and use sanitary procedures  Know first aid 15 MA PHIT- Wastewater Certificate Program, Session 3

Deep Observation Hole 16 MA PHIT- Wastewater Certificate Program, Session 3

Videos Play these videos Deep Hole Observations 17 MA PHIT- Wastewater Certificate Program, Session 3

Soil Suitability and Profile  Soil Suitability and Profile 1. Soil texture 2. Soil structure 3. Pervious material present 4. Depth and thickness of layers 5. Groundwater indicators Image credit: 18 MA PHIT- Wastewater Certificate Program, Session 3

Field Notes 19 MA PHIT- Wastewater Certificate Program, Session 3

Deep Observation Hole Summary  Minimum of two test holes in each proposed SAS including reserve areas for new construction or an increase in flow  10 feet deep  Minimum of one test hole in proposed SAS and one in reserve area for repair (remedial)  Additional holes may be required by BOH—ask for examples  Must be witnessed by BOH and documented if requesting certain waivers on design plan 20 MA PHIT- Wastewater Certificate Program, Session 3

Percolation Testing  Minimum of one perc test in each proposed SAS  Additional perc testing may be required by BOH  Use most restrictive area  Witness by BOH  Documented 21 MA PHIT- Wastewater Certificate Program, Session 3

Video Play this video Percolation test 22 MA PHIT- Wastewater Certificate Program, Session 3

Steps 1. Dig and confirm depth 2. Add water 3. Soak for 15 minutes (called pre-soak) keeping water level at 12” 4. Let water drop from 12” to 9” and record time 5. Let water drop from 9” to 6” and record time on Form Determine the rate 7. What if you’re unable to maintain 12” for pre-soak? 23 MA PHIT- Wastewater Certificate Program, Session 3

Practice PT 1PT 2PT 3PT 4 Time at 12” 12:15 pm9:00 am10:00 am1:00 pm Time at 9” 12:45 pmNoon10:15 am2:30 pm Time at 6” 1:30 pm5:00 pm10:18 am4:30 pm Time 9” to 6” Perc Rate (mpi) if okay for new if okay for repair 24 MA PHIT- Wastewater Certificate Program, Session 3

Key Points  Percolation Testing is not allowed in: ̶ Frozen, non-naturally occurring, or filled/disturbed soils ̶ Fractured or weathered rock ̶ Soils exposed to air for >3 days  Additional Percolation Testing can be required for: ̶ Varying soil conditions or designs over 2000 gpd  Design using the slowest rate  How long are the test results good for? 25 MA PHIT- Wastewater Certificate Program, Session 3

4. Groundwater Determination Deep observation holes also determine estimated seasonal high groundwater elevation. Read more: MA PHIT- Wastewater Certificate Program, Session 3

The onsite system can now be designed. Design considerations include:  Site evaluation results  Source of the sewage  Daily flow  Waste strength/characteristics System Design Considerations 27 MA PHIT- Wastewater Certificate Program, Session 3

Session Recap We discussed:  Design considerations for site evaluation and selection for onsite wastewater systems  Safety on the job site  Requirements for deep observation holes and percolation tests  How to conduct and witness a percolation test  How to determine seasonal high groundwater levels 28 MA PHIT- Wastewater Certificate Program, Session 3