Sanitary Sewer System
Summary • Sanitary Sewer Basics • Town of West Seneca Sewer Districts • Consent Order • Inflow Evaluation • Slip Lining • System Capacity Issues • Leydecker Pump Station • Recommendations
One Person, One Day: 15 gal Flush Toilet 35 gal Shower/Bath 4 gal Brush Teeth JUNE 6 gal 20, 2011 Wash Hands 60 gallons/person* * Typical estimate for design is 100 gallons/person/day Town of West Seneca has approximately 32,000 people connected to the Town’s system. At 60 gallons/person, that is approximately 1.9 million gallons per day (mgd). We would design the system for 100 gallons/person (3.2 mgd). Actual flow data from 2006-2010 shows the system averages 3.74 mgd (approximately 120 gallons/person).
What Happens to Water That’s Not Consumed (and 95% of the water is not consumed)? Goes down the drain Out of site/ } Dirty Out of mind and becomes & Smelly wastewater Hidden
Where does the wastewater go? S E W E R S
What is a SEWER? • Series of pipes • Below ground • Conveys wastewater • Sewer has access points – House connections – Manholes
Wastewater Flow in Sewers Why is the sewer pipe tilted downward? – Water flows by gravity – From high point to low point
How Do We Get Wastewater Up a Hill ? It needs to be PUMPED ! Pumped Gravity Wastewater Wastewater Flow (Uphill) (Downhill) Hill Pump Sewer Sewer
Sewer View From Above 14” Manhole 12” Increasing 8” Joining Pipe Size Pipe Manhole Manhole Changing Pipe Direction 8” 12” Increasing Pipe Size
Why Not Discharge to a River or Lake? • River/Lake – Untreated wastewater will make humans sick – Untreated wastewater will kill fish and other aquatic life. – Impacts water quality • Bacteria/pathogens are harmful – Humans – Fish • Low Oxygen Level – Fish cannot survive
Regulatory Compliance - Consent Order • Imposed by New York State Department of Environmental Conservation (NYSDEC) in 2004, with an amendment in 2008 requiring a number of items, notably: - Generate a schedule for elimination of Sanitary Sewer Overflows (SSO’s) into Cazenovia Creek - Provide an approvable program for control of private sources of inflow and infiltration (I/I)
Infiltration and Inflow • Infiltration and Inflow • Inflow effects size of Sewer – Storm water System • Infiltration – Ground water • Due to: – breaks, cracks, holes, joint failures, connection failures
Private Laterals § 97-23 Prohibited Connections Non-Sanitary Connections. No person shall make connection of roof downspouts, foundation drains, areaway drains, sump pumps, floor drains, such as garage or basement, or other sources of surface runoff or groundwater to a building sewer or building drain which in turn is connected directly or indirectly to a public sanitary sewer. Any such connection now in existence shall be removed. Inspection prior to transfer of title. No person shall transfer title to another person nor accept from any other person the transfer of title to any structure or parcel of land upon which a structure is located until the Town of West Seneca Code Enforcement Officer or his designee shall have inspected the sump pump system, footing drains, yard drains and downspouts of such structure or parcel of land and issued a certificate of compliance stating that the same is found to be in compliance with the provisions of Town Code § 97-23A (Non-Sanitary Connections) and § 97-26 (Certain wastes excluded from sanitary sewers). This section shall not apply to transfers of property by gift, intestacy or testamentary disposition, transfers pursuant to the Bankruptcy Code, partition or matrimonial settlement. Waiver of Certificate of Compliance. The Town of West Seneca Code Enforcement Officer may temporarily waive the requirement for a certificate of compliance as a prerequisite to transfer of title, provided that the purchaser: • Shall file with the Code Enforcement Officer a written agreement to correct any deficiencies to the sump pump system, foot drains, yard drains and downspouts within a period of time to be specified by the Code Enforcement Officer; and • Shall provide a sum of $2,000 which shall be held in escrow by the Town of West Seneca and which sum shall be returned to the purchaser if the corrections are completed within the time specified in the agreement. Such sum will be forfeited to the Town if the corrections are not completed within the time specified in the agreement. – In the event that the connections are not completed with the time specified in the written agreement, the temporary waiver shall immediately expire and the purchaser shall be subject to the penalties as prescribed in Article IX (Enforcement) § 97-46 (Penalties for offenses). § 97-34 Improper usage of sewers. The Town Engineer, Town Code Enforcement Officer, or one of their designees that are employees of the Town, shall have the right to inspect and/or test any building sewer and building drain and appurtenances or private sewers that discharge wastewater directly or indirectly to the Town’s wastewa ter conveyance system. This includes the authority to inspect basements for illegal connections, such as sump pumps. In the case of basement inspection, the Town Engineer or Code Enforcement Officer shall give notice of no less than 12 hours nor more than 48 hours if requested by the owner. If it is found that such sewers or drains are used or maintained in such a way as to cause any discharge that violates this chapter, the Town Code Enforcement Officer will initiate enforcement actions in accordance with Article IX (Enforcement).
Summary of System In addition, there are 3 County Sewer Districts – ECSD #1 – 54 miles, ECSD #3 – 11 miles, and ECSD #4 – 2.5 miles. Total of 245 miles. 8 pump stations and 5 permitted SSO’s and 1 non-permitted SSO.
Summary of System • Average Daily flows are approximately 3.74 mgd. • To put the I/I problem in context, the average daily flow just from District #13 was 9.5 mgd in May 2011!
Sewer Evaluation Map
Inflow/Infiltration Evaluation • 2010 Phase I was • Project is split into 10 studied phases Only 50% of the area was – One phase per year evaluated – Phase based on highest • Conclusion priority identified by – $2.5 Million of testing Construction for amount – Each Phase consisting of studied 60,000 to 70,000 Linear – Assumed $3.5 Million to Foot of pipe replacement (approximately 7% of reconstruct Phase I fully system annually)
Slip Lining From 2000 to 2010, approximately 60,000 linear feet (lf) of sanitary sewer (noted in orange) was sliplined. Approximately 6,000 lf is scheduled for 2011 (blue), and approximately 11,000 lf remains (green). The cost is approximately $250,000/mile.
Review of Overflows January 2011 – May 2011 • SSO #1 – Mineral Springs (Plant 6) 14 times – 13 million gallons (Buffalo Creek) • SSO #2 – Ashmund (Plant 5) 60 times – 132 million gallons • SSO #3 – West Seneca West 34 times – 74 million gallons • SSO #4 – Cranwood (1 overflow – result of sliplining) • SSO #5 – Elmsford 18 times – 7 million gallons
Why do we have Overflows? • The Town discharges into the Buffalo Sewer Authority System. The Agreement requires that the Town does not exceed 12.8 mgd (as a rate). They also discharge into ECSD #4 at a not to exceed rate of 2.17 mgd. This limits the flow that can discharge out of the Town system. • There are several areas where the pipe capacity downstream is less than upstream.
System Capacity Issues
System Capacity Issues
System Capacity Issues
System Capacity Costs • Junction on the 24” interceptor near Mill Rd along Cazenovia Creek - $3 million • Near Emerald Dr. and West Dr. - $5 million • Seneca St. near Main St. - $7 million • Orchard Park connection to the 36” interceptor - $1 million • East and West Rd. near Union - $1 million
Overflow at Leydecker Pump Station Overflow at Leydecker pump station has discharged approximately 15 times since January 2011. Working on a program to eliminate this non-permitted SSO. Estimated cost - $300,000.
Other Items to Consider • Overflow Retention Facility requires repairs. Estimated cost - $200,000. • Pump stations require general upgrade and maintenance. Estimated cost - $400,000. • Additional Miscellaneous items - $100,000.
Existing Sanitary Sewer Rate Structure it’s complicated • Rates are composed of various components: - “Footage” charge for linear footage of road frontage - “Water Consumption” charge per thousand gallons used - “O&M” charge based on a rate per thousand of taxable assessed property value - “Area” charge based on a rate per thousand of the property’s square footage - “Flat Fee” per property depending on the property’s classification - “Debt Service” charge based on a rate per thousand of taxable assessed property value The Town does not charge “footage” if the developer installed the facilities with in a subdivision
Annual Sewer Cost for Typical Residential Property - 2007 Rates vary from approximately $300 to $700 per unit per year Total revenue generated from rates in 2010 was approximately $7.5 million
Recommend
More recommend
