An Accurate Assessment of the Situation Determining a Communitys Wastewater Needs Nick Haig-...

An Accurate Assessment of the Situation

Determining a Community’s Wastewater Needs

Nick Haig- University of Minnesota

Onsite Sewage Treatment Program

haigx003@umn.edu - 612-625-9797

What is a site assessment?

• Analyze records• Determine lot size• Locate well• Probe existing system• Conduct soil boring• Match soils• Determine seasonal

water table depth• Locate potential

drainfield area• Identify treatment

options• Check/pump septic tank

Inspection: Results

1. Certificate of compliance

2. Certificate of non-compliance

3. Imminent Threat to Public Health System (ITPHS)

Local policies affect results and homeowner requirements!BUYER BEWARE!

What about a whole community?

MPCA Unsewered Area Alternative Analysis

1. Replace failed ISTS with new ISTS.

2. Decentralized cluster system.

3. Connect to existing facility.

4. Connect to a facility, which requires an expansion.

5. Construct a new wastewater and treatment facility.

Note: Solution may be a combination of approaches

Determining ‘Decentralized’ Feasibility

Typical assessment:

Complying

&

Non-complying

More complete assessment:

Complying

&

‘Could be’ Complying

&

‘Can’t be’ Complying

Comply Don’t Comply

Minnesota Lake

Typical Assessment

Comply Can’t ComplyCould Comply

Minnesota Lake

More Complete Assessment

Doing the more complete assessment

• Map of parcels• Records:

– Permits

– Age of systems

– Maintenance

• Identify:– Likely compliant

– Spot check

• Properties to be checked:– No records– Possible un-permitted

work– Older than XX years– Suspected problems

• Map of findings

Septic System Components

Source

Tank Drainfield

Treatment in SoilGroundwater

Well

3 feet

Site Assessments: Soil Analysis

Inadequate Vertical Separation

Source

Tank Drainfield

Inadequate TreatmentGroundwater

Well

3 feet Pathogens Nutrients

Mound SystemSource

Tank

Treatment in SoilGroundwater

Well

3 feet

Pump

Mound Treatment Area

What Kind of System is Bad (failing)?

• Leaky Tanks

• Surfacing to Ground

• Inadequate Vertical Separation to Water Table

• Direct Discharge

Drywells or Cesspools

Surfacing to the ground

Direct Discharge (to surface, tile line, or body of water)

Veseli• Examined the records

• Conducted 62 Site Evaluations

• Determined the current status of systems

• Assessed potential solutions for each property

• Evaluated potential cluster sites

• Produced map of findings

• County cost for time, travel, reporting and some overhead - $76.90/site

Results

106 Homes or Businesses

58%

42%

Site Evaluation

No SiteEvaluation

Possible Results

• “In Compliance”- Meets current Rice Co. Ordinance

• “Not In Compliance”- Does not meet current Rice County Ordinance, may need to be upgraded in the future

• “Imminent Threat to Public Health System”- ground surface or surface water discharge, sewage backup into dwelling, drywell or cesspool.

Results• 60 Anticipated Site Evaluations• 62 Final Site Evaluations

• About 60% of community needed to be inspected because of:

No records Unpermitted work Suspected direct discharges

• Several homes have been upgraded since 1992 due to Rice County Septic Ordinance property transfer requirements

Actual Results8

3716

1

In Compliance

Imminent Threat to Public Health

Not In Compliance

No Water

3716

1 8

3

2

32

NIC No Water IC

ITPH-TILE DRYWELL SURFACE

Public Health Threats- Stacked Up

Veseli- Overall Septic Situation1

37

16 14

38

Assumed Compliant Curtain Drain

Not In Compliance ITPH

No Water

106

Buildings

Veseli- Overall Septic Compliance

Community Options(in no particular order)

• Regionalize to Lonsdale (2002 est. = $30,000)

• One “decentralized” collection/treatment system for entire community

• Several “cluster” collection/treatment systems for entire community

• Upgrade all “non-compliant” systems with ISTS and cluster those that cannot fit ISTS

Options (cont.)

• Upgrade systems that pose ITPH with ISTS and cluster where necessary

• Allow new developments but require them to provide wastewater treatment for existing lots currently not in compliance

Site Evaluation Conclusions

Site Evaluation Cost Estimates

Rice County

WW Initiative

Total

Field Work $1925 $1160 $3085

Reporting $240 $312 $552

Overhead $408 $270 $678

Mileage $198 $180 $378

Meals $0 $75 $75

Total $2771 $1997 $4768*

* $76.90/ Site Evaluation

Beaver Lake

Individual “standard” system

Individual “other” system or a holding tank

Individual holding tank

Cluster system

Costs- Beaver Lake

• $500 to local ISTS professional

• In Kind not counted

• $3000-$5000 estimated

Meriden

More complete assessment

• Offers a complete understanding of the current situation

• Basis to look at potential solutions

• Helps determine appropriate boundaries

• Fits with the funding hierarchy changes