Bring On the Retrofit! Len Bramble, Cheryl Robitzsch, and Phil Locke Is has been 40 years since the first generation of pressure-driven membranes were installed in water treatment plants in the United States, and many utilities are now finding themselves in the position of their systems needing an upgrade. As these utilities explore their choices in this current economically challenged environment, difficult decisions need to be made about continuing to dedicate resources and operation-andmaintenance dollars to an aging system, spending high-capital dollars on a new facility, or creatively optimizing and retrofitting their existing systems.
mosis (RO) treatment system in 1975. With this HFF system, Venice owned the largest brackish water RO facility in the world. Due to continuing issues with permeate, the decision was made in 1989 to replace the HFF treatment system with a spiral-wound membrane RO system. Local RO systems manufacturer Harn RO Systems Inc. was selected to fabricate and install the two 1-mgd trains, which was later expanded in the early 1990s by adding two more 1-mgd trains, ultimately bringing the permitted capacity up to 4.64 mgd. This system has served the City well for many years, including periodic replacement of RO membranes.
The System Today
Setting the Stage The City of Venice is a seasonal coastal community along the southwestern coast of Florida, located just south of Sarasota. The general area was first settled in the 1870s, primarily by farmers growing citrus and other crops. Following the completion of the railroad to the area in 1911—the Sarasota-Venice Company—a land development company owned by Chicago businesswoman Bertha Honore Palmer platted a small area south of Robert’s Bay as the town of Venice and offered lots for sale. Rail lines were extended to this newly platted area and the train stop was called Venice Train Station. Venice remained a small fishing resort and farming community until 1925 when Dr. Fred H. Albee purchased 2,916 acres of land from the Venice-Sarasota Company and retained world-renowned city planner John Nolen to design a city on his land. Dr. Albee in turn sold his land to the Brotherhood of Locomotive Engineers (BLE) in October 1925. The BLE hired the noted American landscape architect John Nolen to complete his plan for the new city, and he retained the New York architectural firm of Walker & Gillette as supervising architects and Prentiss French as landscape architect. On June 10, 1926, the first street in Venice, Nassau Street, opened, and in December 1926, Venice held its first town council meeting and formed police and fire departments. In 1928 the first Tamiami Trail was constructed from Tampa, south through Venice, to Miami. The Great Depression saw the end of BLE’s involvement in Venice, but the 1932 arrival of the Kentucky Military Institute and the establishment of the Venice Army Air Base in 1942 aided the city’s turnaround. Venice first found itself in the water business in 1945 when the Army Air Base was vacated, leaving the base utilities to the City. Demand at that time was around 12,000 gal per day (gpd) from shallow wells (<125 ft deep). In 1954, the City purchased a 400,000 gpd lime softening plant. Due to deteriorating water quality issues, the City installed a 1-mil-galper-day (mgd) hollow fine fiber (HFF) Dupont Polymetrics reverse os-
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October 2015 • Florida Water Resources Journal
By 2007, the utility reached a point where it was clear that the RO plant’s aging membranes were in dire need of replacement. Adding to this sense of urgency was the deterioration and corrosion of the skids holding the RO pressure vessels and membranes; an undersized odor control system that did little to control the naturally occurring hydrogen sulfide emissions from the facility; and an old stout, but limited, control system, all needing significant upgrading or replacement. Fueled by this top-priority project, in addition to numerous other significant and highly visible potable water and sanitary sewer facility and asset needs, the Venice Utilities Department began a quest to identify and secure funding for the City’s very first long-range capital improvement plan (CIP). This culminated with a utility rate adjustment in 2010 that adopted a set of rates, fees, and charges, largely for the sole purpose of implementing the utility department’s very first long-range financial plan and first CIP. The financial plan included periodic borrowing to support the CIP, and in late 2010, the City secured the first planned borrowing via a $20 million revenue bond issue. While the 2010 financial plan and rate study were underway, City staff was busy identifying and considering a variety of options to solve the RO plant issues, including such things as building a new RO plant at a different site and renovating the existing RO plant. Following the completion of a preliminary engineering report, which estimated the probable costs to relocate and replace the existing RO plant with a new one, a decision was made to keep the RO plant in its current location and renovate it. This not only accomplished bringing the treatment technology up to date, it also set the stage for the renovation of the entire treatment plant compound, with the water treatment plant setting an example for urban renewal in that portion of the City. The plant is in an area of the city that is one of three principal entryways into the downtown core and is under growing pressure to see it evolve from an older light-industrial area to being more consistent with the more commercial-based central business district that’s adjacent to the west. This of course led to discussions and debate by City staff on the pros