San Antonio River Authority (SARA) owns and operates the Upper Martinez wastewater treatment plant located on the eastern edge of Bexar County. This plant was originally constructed in 1969, and the majority of the treatment processes used at that time have become obsolete. Throughout its years in operation, this plant has been rehabilitated and additions have been made to keep it up-to-date and within the regulations set forth by TCEQ. Recently, facility operations have experienced the plant becoming hydraulically overloaded during rain events, causing the effluent quality to decrease and, in some instances, not meet permitted levels. To combat this problem, the San Antonio River Authority has begun its investigation and has presented options to add either a clarifier or a filter to the treatment process. This would increase the plant's capacity and add another level of treatment to the entire process, helping to ensure that the effluent is Type 1 Reuse Quality.
San Antonio River Authority contacted Construct-Ability to perform proposal evaluations, a constructability review, and cost estimating for installation of the various options. Our team solicited numerous filter and clarifier manufacturers to submit equipment specs and budgetary proposals, and we used SARA's as-built drawings to begin our analysis. To better understand facility operations and the scope of this project, we conducted a site visit, taking photographs, finding the dimensions of existing basins surrounding structures, and locating possible pipe routes.
We normalized the proposals submitted by the four manufacturers in order to determine if all options were being compared on the same level and to identify possible gaps within the scope. A short summary of each scope was then prepared to show the design requirements against the proposed unit capacities. To identify potential construction issues and determine if additional space would be required to install particular units, we performed a detailed review of the retrofitting process. We prepared a brief summary of each unit, listing the pros and cons for each route and including a detailed cost estimate. Our team also incorporated a construction schedule for each option to show the various timelines. Each schedule included the procurement phase timeline that the vendor had allowed for their equipment, the submittal phase, and the construction sequence. Our team found the length of the contract duration for each option and determined which option would require the most management time for SARA.