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8.d)1) Study of the Anderson-Erickson 201 Wastewater Treatment System Meeting Date: 3/20/2012 Agenda Item: �� � ) �� i City Council Agenda Report City of Scandia 14727 209th St. North Scandia, MN 55073 (651) 433-2274 Action Requested: Continue discussion of the study of the Anderson-Erickson portion of the 201 Wastewater Treatment System, which was begun at the March 13, 2012 work session meeting. Deadfine/Timeline: The Council authorized the study at its December 20, 2011 meeting. Background: • The engineering study was initiated in response to an application from James and Sandra Continenza for a variance to allow construction of a new home on Big Marine Lake. The new home and a home next door owned by the Continenza family would both need new sewer service. They would prefer to connect both dwellings to the City's 201 Sewer System. The deadline for review of the variance has been waived to allow time to determine if an expansion of the sewer system is feasible. • A preliminary report was given at the February 21 meeting. The final report was presented at the March 13 work session meeting. The engineers supplemented the report with a one-page summary of options (attached.) • Also at the March 13 meeting, Joe Christensen, Attorney for the Continenzas, submitted a memo commenting upon the study. The memo, along with a memo with comments from the city's engineer, is attached. • The Council directed that steps be taken immediately to implement the repairs identified by the study. Stantec was authorized to immediately proceed with obtaining samples from the groundwater monitoring wells. Discussion was continued to the March 20 regular meeting. • On March 14, Ryan Goodman and Anne Hurlburt met with Pete Ganzel from Washington County to review the report and discuss the strategy for making the repairs. It was agreed that county staff would replace the run-time meters on both pumps during the week of March 19. County staff will immediately close the drain back valve manually and the pumps will be recalibrated with the valve closed, so that precise flow readings can be obtained. Stantec will obtain quotes for replacement of the drain back valve (which must Page 1 of 2 03/15/12 be completed by next winter) and flow meters at the drainfield. • The recommendation to begin dosing two cells of the drainfield while resting one, as the system was designed to operate, cannot be implemented without replacing three valves at the drainfield. Stantec will obtain quotes for this work. • The city has not yet received its permit for the Anderson-Erickson system from Washington County. At our meeting on March 14, we inquired about the status of the permit and were informed that it had been completed but not yet been transmitted to the city. We expect to receive the permit prior to the March 20 Council meeting and will review it to determine its effect on the pending actions to be taken by the city. We have asked Pete Ganzel to attend the meeting. Recommendation: The Council should continue its discussion of the Anderson-Erickson wastewater system. The City Engineer continues to recommend that no new connections be allowed to the Anderson-Erickson system at this time. At a minimum, no decision should be made until flow data has been collected for a time, and results have been obtained from the monitoring well testing. Any possible issues with the county permit must also be identified. Attachments/ • Stantec memo dated March 13, 2012 Materials provided: . Memo from Joseph Christensen dated March 13, 2012 • Memo from Clinton Jordahl, Stantec, dated March 15, 2012 Contact(s): Ryan Goodman, PE (651) 967-4616 Prepared by: Anne Hurlburt, Administrator (Anderson Erickson report) Page 2 of 2 03/15/12 Memo �� To: Ryan Goodman From: Clint Jordahl Stantec, St. Paul MN Stantec, St. Cloud, MN File: 193802153 Date: March 12, 2012 Reference: Anderson/Erickson Wastewater System Options—City of Scandia Do Nothing—Continue to operate the system under the under the County's permit (OP 0400-1). According to the permit, both peak flow (8,600 gpd) and average flow (5,300 gpd monthly average) are targets not limits. However, there is currently no way to determine peak daily flow without reading the meters daily. Replace RTM at main lift station by 1/1/2013, and "investigate" repair of dosing valves by 1/1/2014. 2012 costs are for RTM installed (<$500). Add a Small Mound to Existing Property— Mound adds 2,000 to 2,500�gpd in design capacity, half of which is consumed by existing peak flows of 8,000 gpd. (6,700 +2,500 = 9,200 gpd design flow; 9,200 - 8,000 gpd of existing flow equals t1,200 gpd increased capacity). Cost estimate if permitted by Washington County and nitrate reduction is not required $102,700. Add Pretreatment and Utilize Existing Drainfield— Purchase and install equipment to pre-treat about 15,500 gallons per day, which would accommodate about 45 year- round connections. State of Minnesota would permit system and would have the final say on all design matters. Equipment and O&M cost vary widely. Drainfield modifications required to distribute treated effluent under pressure. Estimated totat cost$300,000 to $500,000 without nitrogen reduction. If end of pipe requirement is <10 mg/L nitrate, add approximately$200,000 in additional equipment. Acquire Additional Land to Expand or Replace System—Assuming a system large enough to accommodate service area, State Permit will be required. The State is unlikely to allow continued use of existing drainfield without pretreatment (refer to pretreatment costs above). Total system replacement is assumed with a build out design flow of about 15,500 gallons per day. Cost of new system with land, about $500,000, plus about$30,000 to replace/upgrading the monitoring well network. If nitrogen pretreatment is required by the permitting authority, add about$250,000 in equipment costs and subtract the monitoring well cost. One Team.Infinite Solutions. , / { , .. �fL.'i,.f� - �^:�!',f� S„'�'�.. 3/13/12 SCANDIA/CONTINENZA 1. Things to fix immediately: • Start dosing 2 cells/year rather than 1 cell/year, manually until automatic valve is fixed (p.3 §2.2). • Fix run tune meter on 1 of the 2 pumps (p.4 §2.3). • Altemately, consider upgrading to programmable logic controller (PLC) with supervisory control and data acquisition (SCAD). (p.4 §2.4). • Initiate sump pump inspection program to eliminate possible infiltration and inflow of surface and/or groundwater to the septic system (p.5 §2.4). • Repair electronically operated drain back valve at main lift station to reduce run time on pumps and help measure flow rates accurately. (p.9 § 4.2). o Enor in stated flow rates from broken drain-back valve is between 25%-55% (per Pete Ganzel). o Actual daily flow is likely between 2,300-3,800 gpd. (per Pete Ganzel) - Not 5,582 gpd. (p.4 §2.3). o Broken drain back valve results in significantly overstated flow rates because stated flow rates are based on run tunes of pumps. o Est. actual daily flow between 2,300-3,800 gpd. means there is between 2,900 and 4,400 gpd. unused capacity available in the existing system. 2. Mounding in e�stin� drain field area. • Expansion in existing drain field area would add from 1,200 gpd. to 2,500 gpd. of additional new capacity allowing connection of at least an additional 5 to 10 homes based on stated flow rates. (pp. 6-7 §3.1). • Using actual flow rates may allow several more homes to be connected because (a) system may have more available capacity than reported, and (b) actual volumes per house are significantly lower than reported. • Estimated costs include: 0 10,000 gallon dosing tank $20,000.00 o Dual dosing pumps $1,400.00 o Mound construction $40,000.00 Subtotal: $74,000.00 0 30% for design, pernutting, Contingencies $22,200.00 Tota1: $96,200.00 � $100,000.00 fmanced at 5% over�Q yr. amortization = $660/mo. $660/mo. = 32 = $20.63/mo./house 1 3. Pretreatment. • May cost something in range of $200,000.00 to $400,000.00, plus extra $100,000.00 for drain field modification, design and contingencies. 4. Acquisition of additional land/system replacement. • Costs may be as much as $500,000.00 without pre-treatment to reduce nitrogen. Pretreatment, if required, would add another $250,000.00. 5. Possible realistic steps City could take. • Complete all maintenance and repair items listed at Sections No. 1 above. • Allow 2 additional connections for Continenzas and Jim's mother and use connection fees to help pay costs. • Consider installing new mound in existing drain field area at some point to increase capacity and allow more connections to help finance future improvements. • As/when needed go to pre-treatment and/or replacement options with bonding and special assessments to fmance improvements. 6. End Notes. P4-§2.3 stated average daily flow for year ended October 2011= 5,582 gpd. Est. actual daily flow likely in 2,300 gpd. to 3,700 gpd range. Stated average 5,582/gpd. =30 homes = 186.67 gpd./home Est. actual average 2,300 gpd. = 30 homes = 76.67 gpd./home. Stated peak 7,500 gpd. = 30 homes = 250/gpd./home � Est. actual peak 3,800 gpd. = 30 homes = 126.67gpd./home Midpoints: Stated = 218.34 gpd./home Est. actual = 101.67 gpd./home 2 new connections would constitute only a 6.7% increase to existing 30 homes on system. There is no better option for either the Continenzas or Jim's mother from either a practical, environmental or aesthetic point of view. 2 Memo S�� To: Ryan Goodman From: Clint Jordahl Stantec, St. Paul MN Stantec, St. Cloud, MN File: 193802153 Date: March 15, 2012 Reference: City of Scandia—Work Session Meeting 3h 3/12 This memo has been prepared in response to several issues raised by Mr. Joe Christensen during the City Council work session meeting held 3/13/12. Specifically, I'd like to address items included in his opening section headed"Things to fix immediately". "Sfart dosing 2 ceJls/year rather than 1 celUyear, manually until automatic va/ve is fixed' Response: Manually opening two valves will result in unequal loading of the drainfield due to elevation differences, uneven head loss due to pipe friction, and other factors. We understand the integrity of the wiring from the main lift station to the automatic dosing valve is in question and we are evaluating the availability of inechanical equipment that could be used to advance the dose sequentially without electrical power. "Fix the run time mefer on 1 of the 2 pumps" Response: As the system is currently operated, fixing the broken run time meter does not significantly improve the quality of the data being collected. Nevertheless, we understand the City's contracted operator intends to replace the broken meter. "A/ternately, consider upgrading to a programmable logic controller(PLC) with supervisory control and dafa acquisition (SCAD�' Response: It does not appear that the City is willing to invest in a PLC or SCADA for the Anderson/Erickson System at this time.With the operational modifications recommended in this memo and more frequent site visits, some of the limitations of the existing data recording equipment can be overcome. "Initiate sump pump inspecfion program fo eliminate possible infiltration and inflow of surface and/or groundwafer to the septic systerr�' Response: Controlling I&I is a recommendation included in our capacity and condition report.We understand these types af connections are already prohibited by Ciry Ordinance and several methods to address illicit discharges were included in our report. One Team.lnfinite Solutions. rjg c:4isera�t2sz{aapda�avocenmkxoso9�wlndowsvempwery in�emet fl�es�contere.«,uooklgndwe�cnzVespon�memos_ts_12(s).uocx Stantec February 16,2012 Ryan Goodman Page 2 oi 2 Reference: City of Scandia—Work Session Meeting 3/13/12 "Repair e/ectronically operafed drain back va/ve at main lift station to reduce run time on pumps and help measure flow rates accurately' Response: The purpose of fhe electronically-actuated drain back valve is to prevent water from freezing in the pipe leading from the main lift station to the drainfield valve box. Since this drain back valve stopped working, a ball valve has been left partially open to allow the pipe to drain slowly back to the lift station. As we approach the end of any threat of freezing temperatures, and as it appears there are check valves in place to prevent drain back from running back through the pumps, the valve could be closed to eliminate drain back completely until at least November of 2012. This action could truly be taken immediately, and with recalibration of the pumps with the drain back valve closed, the City could collect better flow data throughout the summer and evaluate the value of replacing or repairing the drain back valve in the fall. The remainder of Mr. Christensen's memo generally reiterates the findings and conclusions of our capacity and condition assessment report. He insinuates that flow data reported by the City's contracted operator may be 25% to 55% lower than has been reported due to drain back that is unaccounted for in the calculated flow. Response: The drain back rate has never been measured but has been estimated by the operator at 2 to 3 gpm.The drain back rate actually varies as drain back occurs and the head on the pipe decreases from about 40 feet to zero.Therefore there is no way to accurately measure the drain back rate. There is also no timed event counter to determine the how often the pumps turn on and off, and the lag time between pump cycles. The operator reports that there is 800 feet of 3 inch pipe, and if these numbers are correct, the total pipe volume would 280 gallons. If the drain back rate to the lift station is truly 2 or 3 gallons per minute, it would take 1.5 to 2.5 hours for the pipe to drain completely. If the pumps restarted before that time, some of the water stranded in the pipe would be pushed forward to the drainfield. Without knowing the actual variable drain back rate, the number of pump cycles, and the lag time between pump cycles, it is impossible to calculate the true flow the drainfield. Mr. Christensen's conclusion that there is a 25%to 55% high bias in the reported flow rates is highly speculative and relies on improbable assumptions unlikely to ultimately be supported by better data.We would agree that the daily flow data historically reported through the system is higher than the actual flow rate, but there is simply no way to quantify that error or determine the actual flow at this point in#ime. While the current daily flow through the system is important to know from a management and planning standpoint,the council should remember that the current flow through the system includes predominantly seasonal dwellings from which flow will most assuredly increase as they are converted to year-round dwellings. Furthermore, the installation of additional collector pipe has created the expectation that property owners within the service area will eventually be allowed to hook up. Therefore it seems reasonabie to be thinking forward about the ultimate community requirements. . � � �) ►) Department of Public W��I_��Y Lowell Johnson C ll Director �l�DunL� WASTEWATER TREATMENT Sue Hedlund AND DISPERAL OPERATING PERMIT Deputy Director OPERATING PERMIT NO. OP 0400-1 SYSTEM NAME: Anderson-Erickson Collector PERMITTEE NAME: City of Scandia � -}'���'� ,� . . �f 'l,•••..: ADDRESS: 14727 209th St N ��� � � �.� Scandia, MN 55073 . ;`, E: �, �'�..�- '�`` ,�` - .�' : �;' PHONE: 651-433-2274 � �` � �:,; PROPERTY ID. NUMBER (GIS LOCATION): 34032-20-34-0004 �� r���,; �..„ - �:f: SERVICE PROVIDER: Pete Ganzel, C8�B Excavating SERVICE PROVIDER PHONE: 430-6676, 433-3986 Washington County authorizes the Permittee to operate a Subsurface Sewage Treatment System in accordance with the requirements of this operating permit. ISSUANCE DATE: 3/9/2012 EXPIRATION DATE: 12/31/2012 .�.,,,�� � � SYSTEM TYPE: Type I TREATMENT LEYEL: C � .�•� 3 e e * >��-&� SYSTEM DESIGN FLOW: 6700 ,.�;_� � �'� .�£� �`�'� � RESIDENTIAUCOMMERCIAL: Residential ����-' �°��. �' m =� �-°� " SYSTEM COMPONENTS: Septic Tanks, Lift Station and Gravity Drainfield • 29 Individual Septic Tanks ,. � � ; ¢ � • 25 STEP Stations �����;�,�,��,;� �{�,:;. " �-°� „,�.. ,; � .,�, �...� • Pre-Treatment Device: None � • Pump Tank: 3000 • Soil Treatment Area: 6750 lineal 1ft wide. Divided into 3 cells with 2250 each. Government Center • 14949 62nd Street North—P.O. Box 6, Stillwater, Minnesota 55082-0006 Phone: 651-430-6655 • Fax: 651-430-6730 • TTY: 651-430-6246 Service Centers a/so located in Cottage Grove and Forest Lake www.co.washinaton.mn.us Equal Employment Opportunity/Affirmative Action REPORTED MONITORING REQUIREMENTS PARAMETER TARGET LIMITS FREQUENCY LOCA710N Peak Flow GPD 8600 Dail Main Lift Station Avera e Flow GPD 5300 Monthl Main Lift Station cBooS m /L 125 Reference Main Lift Station TSS m i� 60 Reference Main Lift Station Total Nitro en m /L 20 Reference Main Lift Station Field Tests:Tem erature, H, D.O. No Surface Discharge, Ponding to Pondin /Surfacin in Soil Treatment Area Dro Box 4, Sin le Cell Active Quarterl Drainfield MONITORING PROTOCOL Any sampling and laboratory testing procedures shall be performed in accordance with the proprietary treatment producYs protocol, Standard Methods,and at a Minnesota Department of Health approved laboratory. Results shall be submitted to the Washington County Department of Public Health&Environment within 20 days of sampling. Samples must be representative of the flow. Wastewater samples are expected to be taken during average to peak flow events to the greatest extent practical MAINTENANCE REQUIREMENTS SYSTEM COMPONENT MAINTENANCE FREQUENCY Se tic Tanks Pum in /Cleanin of Individual Se tic Tanks Eve 3 Years Semi-Annual or as STEP Tanks and Controls O erational check, um current draw Am s needed Main Lift Tank and Controls Ins ect for dama e, function, um current draw Am s Monthl Inspect for damage, function. Mowing as needed, Gopher Soit Treatment and Dis ersal Control Monthl CONTINGENCY PLAN In the event the wastewater treatment system does not meet required performance requirements as contained in this operating permit, the Permittee shall notify the Department within 30 days of non-compliance. AUTHORIZATION This permit is effective on the issuance date identified above.This permit and the authorization to treat and disperse wastewater shall expire in one year.The Permittee is not authorized to discharge after the above date of expiration.The Permittee shall submit monitoring information and forms as required by the Washington County Department of Public Health 8�Environment no later than sixty (60)days prior to the above date of expiration for operating permit renewal.This permit is not transferable to person or place. The Permittee is required to obtain the services of a Minnesota Pollution Control Agency(MPCA)licensed 1)Service Provider to perform ongoing system operation,maintenance,and monitoring and 2)Maintainer to pump the system's sewage tanks and components. Submit a copy of the signed contract between the Permittee and the licensed Service Provider. If the Permittee fails to comply with the provisions of this operation permit,the Permittee understands that penalties may be issued. If the Permittee sells this property during the life of the permit,the Permittee will inform the new owner(s)of the permit requirements and the need to renew the operating permit. Any extension or new connections to the collection system must be approved by the permitting authority based on collection system and soil treatment area capacity. Page 2 of 3 Additional Conditions; Reporting to the County shall be quarterly but flow readings should be recorded at least monthly or more frequently as determined by the operator. A method of recording actual daily(not average) flow is desirable. Pumps shall be calibrated annually or immediately after alteration of piping or any noted change in pump or panel function and alternation of drainfields. Reference Sampling is a single effluent sample to establish wastewater characteristics. Report ponding as active trenches, drop boxes 1 to 4. Cells 1,2,3. Dosing alternation, frequency and duration, should be as recommended by the City Engineer, or as a minimum, each drainfield cell should be dosed on a rotation basis for one year. Recommended Groundwater Monitoring; Sample downgradient well DS for nitrate nitrogen. Use Well E as a piezometer to evaluate mounding under drainfield. Before 1/1/2013 Replace main lift station pump elapsed time clocks. Make repairs or find alternate for automatic drain back valve on dosing force main. Before 1/1/2014 Investigate repair of electric dosing valves to allow automatic alternation of drainfields. THE OPERATING PERMIT IS HEREBY GRANTED TO Clt�/ O'f SCaIICIIa Permitting Authority Chris LeClair Title: Sr. Environmental Specialist Date:March 09,2012 `—-- �" !-'r�-- Signature: Page 3 of 3