WSSC General Wastewater Engineering Services BOA

The Washington Suburban Sanitary Commission (WSSC) has retained the professional services of PEER Consultants, P.C. (PEER) to perform sewer inspections and develop comprehensive strategies for rehabilitating deteriorating elements of the collection system, especially on large diameter and right-of-way sewers throughout Prince George’s and Montgomery Counties.  The contract also requires the PEER team to address the aging wastewater infrastructure and develop strategies for rehabilitating deteriorating elements of the collection system.  Presently, fourteen (14) task orders have been issued under this BOA.  Each task order is described below:

Task Order 1: Development of Standard Procedures for Inspecting Large Diameter Sanitary Sewers

Prepared a guidance document with standard procedures for inspecting large diameter sanitary sewers (15 inches in diameter and larger) to facilitate structural and operational assessments of large diameter gravity and pressure sewers within the WSSC service areas.

Task Order 2: 18-Inch Horsepen Force Main Contract No. 77CT 3241-B Pipeline Inspection & Condition Assessment

Performed a comprehensive condition assessment of the 18-inch Horsepen Force Main, following a failure in April 2011. Because of the failure, WSSC selected this pipeline as the first force main to be assessed as part of this contract. The goal of the task was to identify high risk areas of corrosion along the force main and its anticipated remaining life expectancy.  As part of the inspection process, PEER conducted a series of tests including internal and external corrosivity surveys using ultrasonic testing and electromagnetic inspection.  PEER used the data collected to provide a condition assessment of the force main and made recommendations for corrosion control methods and rehabilitation procedures for the force main segments requiring repair or replacement.

Task Order 3: General Consulting Services

Provided general support services as instructed by the WSSC, on a per assignment basis. Examples of services performed included GIS applications, Consent Decree and permit reporting, sanitary sewer overflows (SSOS) and basement backups (BBKs) investigations and planning and the planning and convening of a workshop entitled, “The 2014 Advanced Non-Destructive Wastewater Force Main Condition Assessment Technologies Workshop.”

Task Order 4: Emergency Response Plans for High-Risk Wastewater Collection System Assets

Developed a program that provides processes and procedures WSSC to respond to its high-risk pipe assets. Provided the WSSC with emergency response plans for specific pipe asset failures so that they can implement temporary measures in a timely manner and reduce costs.

Task Order 5: Flow Monitoring Network Analysis

Performed Flow Monitoring Network Analysis of metered sanitary sewer sub basins throughout the Commission’s wastewater collection system.  This project documented sewer network connectivity issues and facilitated the creation of sanitary sewer sub basins within existing WSSC sewer basins. Submitted GIS shape files of each metered area of the sub basins to the WSSC, so that they can use these files as a point of reference for continued Rainfall Dependent Infiltration and Inflow (RDII) analysis.

Task Order 6: Preventive Maintenance Optimization and Implementation

Developed criteria and operational procedures for the optimization and reduction in the frequencies of preventive maintenance (PM) such as JET cleaning and chemical root control (CRC) that WSSC uses to maintain gravity pipelines in its collection system. Developed and implemented a process, decision framework, and utilized other software tools to reduce work order backlogs and continually improve the process. The results obtained from this effort - conceptualization, analysis, conclusion and implementation - will serve as the basis for developing a more efficient preventive maintenance program for WSSC’s collection system.

Task Order 7: 16-Inch Reddy Branch Force Main Pipeline Inspection & Condition Assessment

Performed a pipeline inspection and condition assessment of the 2.44-mile, 16-inch diameter Reddy Branch Force Main. The goal of the study was to determine the cause of failure in a specific section of the force main. The failure led to the discharge of two million gallons of sewage into the Reddy Branch Creek, in March 2013.

In order to achieve the project goal, the PEER team conducted a series of key assessments, identifying factors such as operational surge pressures, corrosivity and broken prestressing wires along the force main.  In an effort to prevent similar failures from occurring in the future, the PEER team piloted the SmartBall® technology to determine if this technology could be used to create and implement cost-effective risk management strategies when necessary, and conduct non-destructive condition assessments of prestressed concrete cylinder pipe (PCCP) force mains in real-time.  A number of operational challenges were encountered in piloting the SmartBall® technology, but the challenges were overcome, and information has been gained as to the limitations and benefits in using this technology at this point in time for force main non-destructive inspections.

Task Order 8: WSSC Effectiveness of Maintenance Activities

Verified the effectiveness of the current PMP with respect to sanitary sewer overflows (SSOs) and basement backups (BBKs) by analyzing the available data; specifically work orders, inspections, customer reports, and sewer line BBK data. Major sewer basins with the highest number of SSO and BBK events, were identified and the PEER team  developed a methodology using Key Performance Indicators (KPIs), to augment the effectiveness of the current PMP for those basins. 

Task Order 9: Update of Sewer Analysis Inspection Review Manual

Updated and expanded the existing draft Sewer Analysis Inspection Review Manual which was last revised in July 2011. Revisions made by the PEER team focused on how inspections were reviewed and finalized within the asset management system.  The Sewer Analysis Inspection Review Manual   is used as a reference and training manual for WSSC staff.

Task Order 10: Collection System Performance Assessment Pilot

Tasked to conduct a Performance Assessment (PA) of the effectiveness of sewer improvements required by Articles Two and Six of the Consent Decree for the Patuxent Center Basin.  The PEER team is reviewing the information collected under Article 2 (Collection System Evaluation) and Article 6 (Sewer Basin Repair, Replacement and Rehabilitation Plans (SR3)) to determine the effectiveness of the evaluation and corrective action work performed for reducing sanitary sewer overflows (SSOs) and backups, and to develop a PA template that would be applied to the other 23 WSSC sewer basins.

Task Order 11: Wastewater Force Main Inspection Prioritization 

Developing and implementing a strategic plan for the prioritization of WSSC wastewater force main inspections. Key actions most pertinent to the success of this task include the review of existing data and confirmatory site visits. Deliverables will reflect these findings in the form of a report with plan and priority ranking of the force mains.

Task Order 12: Force Main Valve Inspection and Repair Pilot

Developing a comprehensive force main air release valve (ARV) condition assessment database. PEER will also conduct field inspections on approximately 70 ARV and control valves to determine their condition and need for repair and/or replacement.  The collected data will be used for future assessment of the force main air release valves.

Task Order 13: Sewer Siphon Inspections and Cleaning Procedures

Developing standard procedures to determine, document and update the condition assessment of inverted siphons in the WSSC sewer collection system, in real-time.  All findings will be logged into an electronic database, created by the team. PEER will also create a Model Cleaning Plan that will serve as a guide to prepare cleaning specifications for cleaning contract bid documents.

Task Order 14: Large Diameter Gravity Sewer and Siphon Condition Assessment and Cleaning 

Performing condition assessments as well as pipe cleaning and inspections for gravity sewer segments 36 inches in diameter and larger. The PEER team will also perform cleaning and inspection of selected siphons from 6 inches through 36 inches in diameter, following a report of the existing conditions of select siphons. Prior to field assessments, the team will produce and implement a series of plans addressing but not limited to health & safety, traffic control and response procedures in case of overflow. Field assessments will be carried out using combined CCTV and sonar technologies.  The data gathered and re-inspection of cleaned pipe will be assembled into a referential report, enabling the WSSC to develop erosion and sediment control documents and appropriate plans for future cleaning processes, when necessary.