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Lessons Learned USDA Rural Development Funded Alternative Wastewater Systems.

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Presentation on theme: "Lessons Learned USDA Rural Development Funded Alternative Wastewater Systems."— Presentation transcript:

1 Lessons Learned USDA Rural Development Funded Alternative Wastewater Systems

2 Jon Melhus PE State Engineer USDA Rural Development 952 322-5008

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

4 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

5 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

6 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

7 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

8 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

9 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

10 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


12 Some Comparisons…

13 Discharge Method Surface –9 Systems 4 Failures/Problems 5 OK Sub-Surface –12 Systems 9 Failures/Problems 3 OK

14 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% ?

15 Date of Operation Have we gotten better? OR Are the new systems yet to report failure?

16 O&M Cost vs. System Status Higher O&M costs = reduced rate of failure ? –No

17 Cost per Unit No apparent relationship between cost and success rate

18 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

19 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

20 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?

21 Typical Reasons for Failure/Problem Systems Design –Hydraulically Undersized Design flow I&I –Incorrect Media – RSF’s –Soil Classification/Loading Rates

22 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

23 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

24 Recommendations from Summer 2005 Conference Improve Technical Review Process – RD, State, Outside Experts Establish Education Committee Establish Engineering/Design Standards Committee

25 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

26 Is The Problem Only With RD Funded Projects or State-wide? Not Sure –We’re working with the State to compare data

27 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

28 What Next? RD’s Position –Alternative Technologies Work –RD Will Still Fund and we want to have Preliminary Engineering Reports consider them

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

30 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

31 MOSTCA & On-Site Systems in 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

32 MOSTCA & On-Site Systems in 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


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