Streamlining I/I Repairs in Berlin Charter Township

Transcription

1 Case Study: Streamlining I/I Repairs in Berlin Charter Township Presented by: Rich Grant, PE Agenda Discussion of the problems & the SAW I/I Evaluation & SSES = Asset Management Groundtruthing of Results Overall Result - $$ Savings for the Twp Lessons Learned / Key Recommendations Questions 1

2 Key Points Collection System I/I = Very Expensive Mass Flow Monitoring: Saves Money -What we did that s new vs. traditional data collection -$$OldWay(flow metering many events, BigCCTV) New way Highly Targeted Construction saves money The Problems At a Glance Collection System Assets: water filled New permit limits: December 2007 Prior to Dec. 2007, ammonia was report only New limits were hard to consistently achieve May-Sept 1.4 mg/l Oct-Nov 5.1 mg/l 2

3 Immediate NPDES Permit Reqs NPDES Permit Issued December 2007 New Ammonia Nitrogen Limit WWTP not designed for NH3 treatment Exceedences occurred immediately w permit Capacity of this asset immediately impacted Clean cold water interferes with NH3 treatment Upcoming NPDES Permit Reqs MDEQ draft; revised September 20, 2012 Part 1.A.X(a number). Operation, Maintenance & Replacement/Asset Management The permittee shall at all times properly operate and maintain all facilities (i.e. sewer system, treatment works, as defined in Part 41 of Act 451, 1994 as amended, and control systems) which are installed or used by the permittee to operate the treatment works and sewer system and achieve and maintain compliance with the conditions of this permit (also see Part II.D.3 of this permit). The requirements of an asset management program listed below contain goals of effective performance, adequate funding, and adequate operator staffing and training. Asset management is a planning process that ensures gaining optimum value for each asset and providing the financial resources to rehabilitate and replace them when necessary; and typically includes five core elements which identify: the current state of the asset, the desired level of service (e.g., per the permit, or for the customer), the most critical asset(s) to sustain performance, the best life cycle cost, and the long term funding strategy to sustain service and performance. The permittee shall comply with the following Operation, Maintenance and Replacement (OM&R)/Asset Management program requirements (the permittee can choose to include the Operation and Maintenance Manual required under Part II.C.14 of this permit as part of this program): a. Maintenance Staff. The permittee shall provide an adequate staff to carry out the operation, maintenance, repair, and testing functions required to ensure compliance with the terms and conditions of this permit. The level of staffing needed shall be determined taking into account the work involved in operating the sewer system and treatment works, planning for and conducting maintenance, and complying with this permit. b. Collection System Map. Within months of the effective date of the permit, the permittee shall complete a map of the sewer collection system it owns and operates. The map shall be of sufficient detail and at a scale to allow easy interpretation. The collection system information shown on the map shall be based on current conditions and shall be kept up to date and available for review by the Department. Such map(s) shall include, but not be limited to the following: 1) All sanitary sewer lines and related manholes; 2) All combined sewer lines, related manholes, catch basins and CSO regulators; 3) All known or suspected connections between the sanitary sewer or combined sewer and storm drain systems; 4) All outfalls, including the treatment plant outfall(s), combined sewer treatment facility outfalls (RTBs), untreated CSOs, and any known SSOs; 5) All pump stations and force mains; 6) The wastewater treatment facility(ies), including all treatment process; 7) All surface waters (labeled); 8) Other major appurtenances such as invested siphons and air release valves; 9) A numbering system which uniquely identifies manholes, catch basins, overflow points, regulators and outfalls; 10) The scale and a north arrow; and 11) The pipe diameter, date of installation, type of material, distance between manholes, and the direction of flow. 12) The manhole interior material, GPS coordinates (optional), rim elevation, and invert elevations. c. Inventory and assessment of fixed assets. Within months of the effective date of this permit, the permittee shall complete an inventory and assessment of operations related fixed assets. Fixed assets are assets that are normally stationary, for example pumps, blowers, and buildings. The inventory and assessment shall be based on current conditions and shall be kept up to date and available for review by the Department. The inventory shall include the following information: 3

4 The Problems At a Glance High Flows of Clean Water Received at WWTF Every spring During heavy rain events Both infiltration and inflow suspected Berlin Township WWTF Influent Flows and Precipitation mgd Inflow Flow, MGD Infiltration Precipitation, inches /1/2007 7/20/2007 2/5/2008 8/23/2008 3/11/2009 9/27/2009 4/15/ /1/2010 Date precipitation Influent Flows Dry Sewage, est 0.0 4

5 The Problems At a Glance High flows resulted in: Operational challenges at the WWTP TSS % removal violation (Feb/Mar/Apr 2009) Effluent ammonia violations (spring 2009) Operations staff storing excess water in the collection system to prevent permit violations Sanitary Sewer Overflow (March 2009) I/I Evaluation Analytical Review SRF Guidelines: dry sewage is 70 gpcd Township has 3,600 sewer customers, or approx. 4,200 equivalent people Dry sewage should be around 0.29 mgd Annual avg. flow was 0.66 mgd ( ) 0.84 mgd avg Mar/Apr/May = 201 gpcd, higher than 120 gpcd thus excessive infiltration/inflow 1.5 to 2.0 mgd was not unusual 5

6 Sewer System Evaluation Survey Analytical review indicated both infiltration and inflow but overflows were at Lilly Patch Purpose of SSES: identify specific sources of infiltration & inflow Total Wastewater Flow: St Charles Plus Lilly Patch Lift Stations Wastewater Flow (MGD) /7/2011 3/21/2011 4/4/2011 4/18/2011 5/2/2011 5/16/2011 St Charles Lilly Patch WWTP Influent SSES Setup / Approach Relatively large collection system for the number of sewer users (22.5 miles) Many smaller sewers feeding two main trunk sewers into the WWTP Needed: cost effective way to do SSES 6

7 The old way of collecting SSES Data Hey, ya wanna be on my storm team? SSES Setup / Approach SSES Setup / Approach Mass Flow Monitoring Inexpensive rental was $4/day per Flostick Easy installation no confined space entry Many data collections locations Image courtesy of FloCis Corp. 7

8 SSES Setup / Approach Install the mass monitor sensors in key manholes in the system Data Collected Wastewater temperature Water depth Relative velocity ( wiggle-waggle ) Near continuous data collection Data collected every 5 minutes at each of 38 locations for 9 weeks West District divided into 13 subdistricts 8

9 SSES Setup / Approach East District - divided into 3 subdistricts SSES Results Mass monitoring allowed us to pinpoint which subdistricts were contributing I/I Knowing sewer diameter, slope, and depth of water allowed us to estimate flow rates Pump station flows were estimated using pump run time to help calibrate flow rate estimate 9

10 Example Inflow Result FloStick #26, inflow indicated by increasing depth correspond to decreased temperature Rainfall Water Temp Depth Example Infiltration Result FloStick #12, depths remain high for a while after rain event and temperatures are relatively stable Rainfall Water Temp Depth 10

11 SSES Summary of Results Most of the flow is coming from the West District Confirmed that the East District previously lined, only contributed minimal inflow, not much infiltration SSES Summary of Results Confirmed surcharging of the main trunk sewer during larger rain events as operator uses collection system for storage to keep WWTP in compliance SSO in manhole in East District was due to a hydraulic roadblock Prioritized key segments for improvements 11

12 Total Wet Weather Total Inflow can be Infiltration/Inflow Inflow Removed Total Infiltration can be Infiltration Removed Remainder Prioritized - North Swan Creek Area segment to be lined/rehab d as part of SRF Project 12

13 Ground-truth the Mass Monitoring Wikipedia: Ground truth a term used in remote sensing; refers to information collected on location. Verifies image data to real features and materials on the ground Ground-truth the Mass Monitoring System-wide smoke testing Televising of key sewer segments ~5mi/22.5mi Confirmed results of SSES 13

14 Ground-truth the Mass Monitoring Smoke Testing Ground-truth the Mass Monitoring 14

15 Ground-truth the Mass Monitoring Smoke Testing Groundtruthing of Mass Monitoring Sewer Televising 15

16 Groundtruthing of Mass Monitoring Sewer Televising Overall Result Prioritized Rehabilitation Township did not have to line entire lengths of large diameter trunk sewers Key manholes Expected $2.25M reduction in Project Sewer Rehab Component Cost from $3.75M => $1.5M 16

17 Overall Result Under construction $150K Mass Flow Monitoring/Analysis $160K CCTV, Smoke Tests, Inspect ns ~$2M construction scope reduction Post-construction validation planned to measure amount of I/I removed & confirm it met Township s goals of 40% removal So What s New? Mass Monitoring for cost reductions, improved data, BIG data every storm Confined space entry? nope Targeted CCTV work Assess the whole system with SAW$ Ready for NPDES permit Asset Management req s 17

18 Questions? Richard Grant P.E. Fleis & VandenBrink Engineering