The Vendor is required to provide to conduct a comprehensive inflow and infiltration (I&I) study of the town’s sanitary sewer collection system.
- The study aims to identify sources of I&I, quantify their impact, and recommend cost-effective solutions to reduce extraneous flows, ensuring compliance with Department regulations and optimizing system capacity.
- During significant rain events, flows can increase substantially due to I&I, contributing to sewer overflows, basement backups, reduced treatment capabilities, reduces redundancy capabilities, and increased treatment costs.
- Data collection and review
• Review existing sewer system maps, GIS data, flow records, and past I&I studies.
• Identify data gaps and recommend additional data collection needs.
- Flow monitoring
• Install and maintain flow meters at a minimum of 12 key locations in the collection system for a period of 8 weeks, including wet and dry weather conditions.
• Correlate flow data with rainfall and groundwater levels to quantify I&I contributions. - Field investigations
• Conduct manhole inspections (minimum 100 manholes) to assess structural condition and identify inflow sources (e.g., leaky covers, cross-connections). 
• This will include an inspection of the inverts.
• Current and past CCTV inspections may be able to be provided to the bid winner by the sewer line maintenance division (SLM). 
• If no CCTV inspections can be provided at a location, perform closed-circuit television (CCTV) inspections. 
• This could be of at least 20,000 linear feet of sewer pipes to identify infiltration sources (e.g., cracks, faulty joints).
• Conduct smoke testing in priority areas (minimum 5,000 linear feet) to detect inflow sources, such as illegal sump pump connections or downspouts.
• Perform dye testing where needed to confirm suspected inflow sources. - I&I analysis
• Quantify I&I volumes using million gallons per day (MGD) or equivalent metrics.
• Identify high-priority areas with excessive I&I based on flow monitoring and field data.
• Assess the impact of I&I on system capacity, treatment costs, and sanitary sewer overflows (SSOS).
- Recommendations
• Develop a prioritized list of rehabilitation and repair strategies, including trenchless technologies (e.g.
cured-in-place piping) and open-cut methods.
• Estimate costs for recommended solutions, including capital and maintenance expenses.
• Propose a plan to reduce I&I by at least a 3:1 ratio in targeted areas, per deep guidelines.
- Contract Period/Term: 1 year
- Questions/Inquires Deadline: June 23, 2025