September 2017

34 BUILD / September 2017 , b) The modular chambers of the SPI are equal in weight and size to standard manholes and as such, no specialised heavy equipment is required for assembly; c) Contractors involved with the installation of SPI’s can assemble the parts as per drawings and specifications supplied by Storm Pal Inc. with relative ease; and d) The SPI can be modified to adapt tight fitting field conditions. 3. Effective at high flow – During extreme rain events, most competing interceptor treatment systems tend to bypass the treatment area. This means that during high flow situations, which typically contain the greatest amount of deleterious material, the water is discharged directly into the city storm sewer or receiving water body. In the case of SPI, the storm water systems are designed to treat up to a 10-year storm event at full efficiency. In addition, during greater than 10-year storm events, initial water treatment is still provided within chamber #2 of the SPI. 4. Lower maintenance requirements – Independent of the type of interceptor, the systems must be periodically maintained to remove deleterious substances and sediments that have been captured by the interceptor. Maintenance activities include routine inspection and cleaning of the capture mechanisms. In the case of the SPI, the systems are less prone to clogging due to the design. In addition, the SPI continues to operate at maximum efficiency until the sediment level in chamber #1 reaches the depth of the pipe leading to chamber #2 (refer to Figure 1a). This is not the case for competing inceptor systems, where initial sedimentation can significantly influence future removal efficiency. Consequently, the SPI has lower maintenance requirements (i.e. frequency of clean-out) when compared to other treatment systems, and operates at maximum efficiency for a greater period. 5. Cost effective – Purchase and installation of the Storm Pal system is typically 10 – 25% lower cost than other competing products. 6. Operationally effective – Storm Pal Inc. has been conducting in-situ testing of SPI units to evaluate the efficacy of the treatment system. Testing has involved measuring the concentration of total suspended solids (TSS) within chamber #1, chamber #2, and downstream of the SPI unit. General results indicate TSS removal efficiencies ranging between 81-98%, depending on the flow rate (refer to Table 1). Studies have also been conducted of the particle size distribution of sediments retained within Chamber #1 of the SPI using a computerized digital image system. These analytical results support the retention of fine clay and silt particles, high efficiency of TSS removal, and low scouring based on particle size distribution of solids that are captured by the system (refer to Figure 2). As previously indicated, annual inspection and maintenance of the SPI is required for the system to operate effectively. The regularity of sand/sediment and heavy debris removal present in the bottom of each treatment chamber depends on the amount collected relative to outflow orifices (refer to figure 1). Any suspended oil and grease that is collected within chamber #1 should be pumped out prior to seasons with high precipitation. The unique design of the overflow bypass system allows the system to continue working in the event the primary treatment chamber fills with sediment. Moreover, the SPI design can be easily adapted to accommodate difficult site conditions (i.e. minimal space) and varying geologic conditions. The storage capacity of both tanks can also be increased to handle larger flow volumes on an as required basis. In summary, the Storm Pal is the most affordable, versatile and easily adaptable storm water interceptor system that can be applied to varying site and geologic conditions. The SPI is easy to install, operates effectively in high flow conditions, and requires the least maintenance when compared to other storm water interceptor products. Finally, the efficacy of the product has been demonstrated by routine sampling of the storm sewer effluent upstream and downstream of the SPI’s. Thus, it is anticipated that SPI’s will be the primary choice for suppliers and contractors in the future, and as such, it is the expectation that Storm Pal Inc. will take the lead in the design, installation and maintenance of storm water effluent treatment systems.