By BEN GRAFTON
Comments at a Freeport City Council meeting on Nov. 9 concerning the possibility that a major power outage could cause health problems for some sewer customers prompts a closer look at the situation.
Prior to the slide into recession, real estate development in the Freeport service area was, as was the rule elsewhere in northwest Florida, projected to expand exponentially. Developers were proposing new subdivisions, town home projects, shopping and office centers and other projects at a rate that was difficult to keep track of. Properly so, there was also pressure to provide sewer service for new and existing developments in order to minimize the number of septic tanks already in wide use. The requirement for the city to provide infrastructure for this boom led to the expansion of Freeport’s sewage plant to a design capacity, according to Engineer Charles Peters, of approximately 750,000 gallons of sewage per day.
The original Freeport sewage collection system was a relatively compact gravity flow design in which sewage was fed by gravity into a large diameter main that fed lift station pumps at selected sites. These pumps fed the waste into the sewage plant for treatment. But the expansion around Freeport was far reaching and a gravity collection system for so large a service area was too costly to consider. So an alternate design, sometimes used in rural areas, of a smaller diameter low pressure sewer main fed by individual pumps, referred to as canister lift stations, located on the users properties was selected.
The canister lift stations consist of a small reserve tank fed by gravity from the user’s residence or business. The tank is equipped with a level control that activates a pump (sometimes called a grinder) when the volume in the tank reaches a predetermined level. Normally, when the level control turns the pump on, the tank has 30 to 50 gallons of empty waste storage available. Typically, according to Peters, a residential user pumps about 150 gallons of waste into the sewage system each day.
As things turned out, the recession set in, and expansion ceased. At the present time, according to information received from City Clerk Robin Haynes, Freeport now has slightly more than 1,000 sewer customers about 90 percent of whom are on the original gravity flow system while the remaining roughly 10 percent use the canister lift stations to feed raw sewage to the treating plant.
Haynes has reported that some potential customers for city sewage treatment who are located in the areas served by the canister lift stations are reluctant to sign on for service. They cite a concern that in a major power outage like those associated with hurricanes the canister system would shut down, causing sewage to back up into the residence creating a health problem. They claim they do not have this problem with septic tanks.
Mayor Mickey Marse points out that under hurricane rainfall conditions the ground becomes saturated with water causing septic tanks to flood with resulting contamination of the soil and of nearby bodies of water. Following this, return to normal operation is a time consuming process.
Marse and Peters agree that the canister lift stations, which use small pumps of about one-half horse power according to Marse, can be operated by power from a user-owned small emergency generator to which can the pump can be wired. They also point out that in the Freeport service area, many homes and businesses already have a suitable generator to provide power to refrigerators and freezers during extended power outages associated with hurricanes. These units could also be used to power the pump.
Marse says that the sewage plant is operating at only about one quarter of its rated capacity. At this rate plant efficiency is not as good as it would be if it was operating at a higher rate. He would like to have more customers for better efficiency. He also says that the plant is designed to provide reclaimed irrigation water for parks and common areas, but at the low operating rate the amount of reclaimed water that can be produced does not meet existing demands.
By BEN GRAFTON