lessons learned usda rural development funded alternative wastewater systems

Lessons LearnedUSDA Rural Development Funded

Alternative Wastewater Systems

Jon Melhus PE

State Engineer

USDA Rural Development

952 322-5008

jon.melhus@mn.usda.gov

Alternative WW Systems

• RD Funded Alternative WW Systems– Definition– History– Recent Problems– Lessons Learned/Looking Ahead

Definition of “Alternative” Wastewater System

• This is Jon’s definition

• Different than traditional RD funded treatment systems, which largely consisted of ponds, regionalization & mechanical plants

Types of Alternative WW Systems

• In general, RD has financed three types of alternative systems:– Constructed Wetland/Re-circulating Gravel

Filter– Sand Filter – Soil Based Disposal

Why Alternative Systems?

• Several hundred unsewered areas in MN

• Available grant dollars on downward trend

• Traditional treatment systems often have high capital costs

• If alternative costs less (construction and O&M), than we can help more communities

Timeline• 1998 – Present

– Promote Alternative Systems • 1998

– First RD alternative system funded• 2003

– Failures/extent of problem started to become apparent• 2004

– More problems, consulted outside experts• 2005

– State funding of repairs ($5M for 6 towns), on the road to recovery– July conference of experts, funders, regulators

• 2006– State may fund more repair/replacement

Status of RD Funded Alternative WW Systems

• 21 Systems constructed since 1998• 4 Systems in operation less than one year• Of the 17 systems in operation more than

one year:– 30% have failed outright– 40% are operating below expectations or

experience intermittent problems

Definitions

• Failure– Systems simply don’t work

• Mounds - water draining out side

• Sand filters - flooding and/or freezing

• Cannot handle flows

• Permit limits not met on a regular basis

Definitions cont.• Intermittent Problems

– Freezing during coldest winter periods– Significant amount of additional operator time– Occasional failure to meet permit limits– Wetlands - flooding, plant survival rate

• Bottom line – system may not last, or work as intended, for length of loan/design life

Some Comparisons…

Discharge Method• Surface

– 9 Systems• 4 Failures/Problems• 5 OK

• Sub-Surface– 12 Systems

• 9 Failures/Problems• 3 OK

Permit Agency vs. System Status

• 8 County Permitted Systems– TOTAL: 6/8 Failure/Problems = 75%

• 12 MPCA Permitted Systems– TOTAL: 6/12 Failure/Prob = 50%

• 1 Tribal Permit– 1 Problem = 100% ?

Date of Operation

Have we gotten better?

OR

Are the new systems yet to report failure?

O&M Cost vs. System Status

• Higher O&M costs = reduced rate of failure ?– No

Cost per Unit

• No apparent relationship between cost and success rate

Repair/Replace

• A failure is not necessarily a total loss – Collection system may be OK/salvaged– An intermittent problem could be tweaked to work

• Repair/replace may cost more than original project• 2005 - State of MN has kicked in $5M for failing

systems• 2006 – State has proposal of $6.5M for problems

Typical Situation

• Small Town <100 residents

• Never had a complying system (might have a central sewer but no treatment)

• Low income/Elderly residents

• Little or no growth in the last 20 years

• Small lot sizes

Why Failure/Problems?– Design

• Independent third party reviews show majority of responsibility lies here for outright failures

– Construction• added to problems in some cases

– Operation & Maintenance• Much of the problem for intermittent problem

systems

– Other?

Typical Reasons for Failure/Problem Systems

• Design– Hydraulically Undersized

• Design flow

• I&I

– Incorrect Media – RSF’s– Soil Classification/Loading Rates

Typical Reasons for Failure, contd.• Construction

– Incorrect materials– Installation & Methods– Lack of inspection/proper inspection

• O&M– No O&M manual– Failure to pump tanks – solids pushed through– Cleaning UV system

July 2005 RD Alternative WW Conference

• Four day conference held 7/05• Attendees

– Funders– Regulators– Technical Experts

• Two days in meetings• Two days in field visiting problem systems

Recommendations from Summer 2005 Conference

• Improve Technical Review Process – RD, State, Outside Experts

• Establish Education Committee

• Establish Engineering/Design Standards Committee

What is RD doing?• Independent studies/review • In general, no additional RD funds until

determination is made as to cause of failure• Require borrowers to seek remedies from

responsible parties• Working with others to identify design/O&M

problems• Improve review process• Held conference - summer 2005

Is The Problem Only With RD Funded Projects or State-wide?

• Not Sure– We’re working with the State to compare data

What Now?• Stop The Bleeding

– Repair/replace current problem systems– Prevent future failures

• Everyone has been affected– Bad name for technologies– Engineers– Lack of trust– Funders– Regulators– Taxpayers

What Next?

• RD’s Position – Alternative Technologies Work – RD Will Still Fund and we want to have

Preliminary Engineering Reports consider them

Food For Thought

• Water Systems– RD also funds Water Systems– Wide variety of treatment– Some pilot projects, etc.– Nowhere near the amount of problems

Lessons Learned

• Technical Review– Establish Review Committee– Better job of estimating true costs for construction and

O&M

• Develop Design Guidelines • Capacity Development

– Establish Education Committee– Improve ability of borrowers to manage projects

MOSTCA & On-Site Systemsin RD Funded Projects

• There is definitely a growing need for on-site and cluster systems– Reasons:

• 1. May be more cost effective for small users

• 2. May be easier to operate and maintain

MOSTCA & On-Site Systemsin RD Funded Projects contd.

• Hurdles– 1. Acceptance by communities that this is really state of

the art for them– 2. Central Ownership and maintenance required by RD– 3. How to get everybody into the system (esp. those

that have working OSTS)– 4. No man's land

• Too big for designers, not on engineer's radar• Designer may have to find engineer to work with when over

10,000 GPD – possible State rule changes

QUESTIONS?