City of Hutto South Wastewater Treatment Plant

Project Purpose

Based on the Wastewater Master Plan completed by KFA in November of 2012, it was projected that the city of Hutto would exceed the capacity of its existing wastewater treatment facilities by the summer of 2015. The city of Hutto’s previous wastewater treatment facility permitted for an annual average daily flow of 1.7 million gallons per day (MGD). The existing treatment facility is comprised of two individual plants, Plant #1 and Plant #2. Wastewater flow projections developed as part of the recently completed Hutto Regional Wastewater Master Plan by KFA indicated that the rated plant capacity of 1.5 MGD will be exceeded in the year 2015. The limitations on existing wastewater treatment capacity make the design and construction of new treatment facilities by the year 2015 an important element to accommodate the projected population growth within the city’s service area. The city has elected to build a new 2 MGD Wastewater Treatment Plant. The city had obtained a discharge permit for the new treatment facilities. The permit limits the annual average effluent flow to 2 MGD and the 2-hour peak effluent flow to 8 MGD.

Project Approach

KFA was selected to lead the design of the new Hutto South Wastewater Treatment Plant. The services performed by KFA in the scope of this project were organized into five phases: Preliminary Design, Final Design, Bid Phase, Construction, and Warranty Phase Services. The primary purpose of the Preliminary Design Phase was to identify a treatment process; equipment preferences; odor, noise, lighting and visual mitigation methods; and desired ancillary facilities. This phase included development of a contingency plan to add additional treatment capacity at the existing plant to provide for greatly accelerated flow increases or an unexpected delay in construction of the new plant. The Preliminary Design Phase resulted in a Design Report and 30% Construction Plans. After evaluating different alternatives, KFA determined that a sequencing batch reactor (SBR) was an optimal solution over a conventional flow-through plant. The SBR was chosen for its cost savings and ease in future plant expansion. The Final Design Phase built upon the results of the Preliminary Design Phase and resulted in an updated Design Report and construction documents. Bid and Construction commenced upon acceptance of the construction documents and authorization to proceed

Project Results

As the new plant was located near existing homes, odor, noise, and light pollution control were important aspects of this project that the KFA Team needed to address. Through an accelerated schedule, KFA was able to work closely with the city to ensure plant completion prior to the existing WWTP having its capacity exceeded.