The City of Vero Beach has been a pioneer in installing STEP systems. In a case study of Vero Beach, approximately 1,500 residents were on septic systems. The conversion to a gravity sewer system was estimated to be approximately $22.5 million. The additional costs of connecting the residents to sewers was to be an additional $18 – $22.5 million.
Using the STEP system, the build out of the infrastructure for residences was estimated to be $11.0 million and the residential connections costs were less than $1.0 million. Since 2015, 350 residents have converted, and they are pleased with their results.
How the STEP system works
Over the last four years, the City of Vero Beach have learned a lot on how to solve this issue. The existing septic tank and drainfield are replaced with two plastic replacement tanks that collects all wastewater from the home via gravity. It is important to understand that each home produces raw waste. Unlike a grinder pump, which operates in a highly corrosive raw waste environment, a STEP system begins its processes by separating raw waste into solids and liquids. The liquids are called effluent and only the liquid effluent comes in contact with the pump. This is key to the operation and longevity of the STEP. This extends the life of the STEP system pump significantly beyond the 3-5-year life expectancy of a grinder pump (discussed here)
The main tank for an average home size is a Roth 1,060-gallon MultiTank. Its construction is unique. The tank has an inner layer of FDA approved virgin HDPE, two inside layers of Polyethylene (PE) for improved stability, plus one outer layer of black and UV-stabilized PE. Not only is it special in terms of its construction, it also has the best warranty the industry has to offer: lifetime corrosion protection and 5 years of labor insurance coverage. While the city has designed, specified and supplies the components, independent contractors are used to install them. When the homeowner replaces the tank, the City of Vero Beach takes full responsibility for life of the entire STEP System.
In the main tank, solids settle to the bottom, and the liquid effluent flows by gravity to a second smaller Roth 500 gallon holding tank. Periodically, an Orenco well pump moves the liquid through a washable filter from the small tank into a 1” line, then a 2” line at the street where it is then delivered to a 4” main line and then to the wastewater treatment plant. In the 4 years of operations, no main tanks have needed pumping out yet and no filters have needed cleaning. When they do, Vero Beach will cover the costs.
Several check valves placed at strategic points within each STEP system prevent effluent from reentering the system or home. Venting utilizes the existing roof vents on the home. Therefore, there is no odor build up in neighborhoods. There is an additional bonus for seasonal homes. No special preparation is necessary during periods of no occupancy.
Because 1,” 2” and 4” lines are used, directional drilling techniques are used which lower installation costs when compared to typical gravity fed sewers. Directional drilling can be used for connections several miles away from existing trunk lines. There is virtually no disruption to traffic, large trees and landscaping. The STEP design utilizes a simple water pump and low water pressure to move the effluent rather than gravity. Because only liquids are being moved, the simple water pump used is less costly and relatively maintenance free. Ongoing costs to the homeowner are usage based and capped at $55.79 monthly. No easement is required for installation.
The electrical control box, mounted outside the home, monitors a set of sealed floats (switches). When the effluent tank reaches its capacity, the control panel turns the pump on and then off again when the pump out is complete. Should the pump ever attempt to run without liquid in the effluent tank, an alarm will sound. In case of power outages, the STEP design includes an electrical box that has several unique features.
- First, the boxes are not locked so that the homeowner can access in internal backup features. In preparation for a known or predictive weather event, homeowners can throw a simple inside switch and pump out the smaller effluent tank. This assures them of several days’ capacity, approximately 325 gallons. This is considered equivalent to about 100 events such as brief showers and toilet flushes.
Secondly, each electrical panel has a built-in plug to accept an external generator. The STEP does not need to run constantly, just periodically when the effluent tank reaches capacity. The ½ horsepower pump can be run with any small generator handling as little as 2,500 watts of power. Either the homeowner or city can just come by and connect a generator for a few minutes, empty the effluent tank into the sewer system and provide a few more trouble-free days of use.
While Vero Beach has not had an extended power outage in the last 4 years, they believe that their 140+ lift stations can keep the sewer lines flowing during any extended power outages and the ease of applying external power in emergencies make the STEP a reliable replacement for septic systems.
The City determines which neighborhood is to be converted and informs residents of the plan and start date. For a typical three-bedroom house, the cost to a homeowner is $7930. However, if a resident connects within one year of the start dates and pays cash up front, they receive an incentive credit of $3,390. The incentive brings the cost to the homeowner down to $4,540. The city’s Water and Sewer Department have designed a low cost and reliable solution to the septic system problem. For those who are environmentally concerned, 100% of all nutrients enter the sewer system, not the ground water. We applaud Vero Beach for its visionary approach to this issue.