These days a sanitary sewer overflow (SSO) or wastewater spill of any size can be a major issue, involving repairs, cleaning, and/or replacement to correct the problem. For operators, this is the easy part; because of media attention, public notification, and regulatory fines, we’re in the spotlight when these events occur.
We all are in a profession that is not used to being much in the public glare. Traditionally, we are behind-the-scenes professionals doing our best to keep things flowing and operating properly. At times, it can be challenging to keep things running smoothly, all day and every day, without incident.
Anytime a utility has a SSO spill that hits the waters of the state or is over 1000 gallons, we are required to notify the state watch office and put the incident on the public notification website through the Florida Department of Environmental Protection (FDEP). With this step, we must be more focused on preventive measures.
It’s best to look at each and every lift station in your collection to be sure of proper operation and continued service. Another good practice or measure is line cleaning, jetting, or checking manholes of known hot spots in your system, where blockages have occurred in the past, to keep thing flowing smoothly.
Lift Station Basics
In my humble opinion, the key to preventing a majority of spills is proper lift station maintenance and operational setting or controls. As you all know, the lift station moves wastewater from a low point in the collection system and pumps it to a higher point to restart the gravity flow and direct it to the wastewater treatment plant through a force main. For reference, look up Chapter 62-604, Florida Administrative Code (F.A.C.), which lists the requirements for design, operation, and maintenance for proper lift stations. These stations and collection systems must be designed and operated to protect public health, ensure proper flow, remove waste streams, and be energy efficient in their operation.
Chapter 62-604, F.A.C., requires that basic measures be in place:
- Two same-kind pumps installed in the station. With either of them out of service, the other pump will have the capacity to handle the flow at peak hourly flow.
- Visual alarms and audible emergency alarms that function in the event of a high level in the wet well
- Control access to prevent the public from entry in the lift station area.
- Control panel that has surge protection.
- Periodic inspection of the lift station and its mechanical equipment.
In your system, start by looking at the pumps in each station. Some questions that come to mind include:
- Are all pumps running?
- Is there a backup option?
- Are they keeping up with the flow?
- Is the pump down and run times equal for each pump?
- Does this pump keep having issues?
We should try to have all the pumps running in a duplex or triplex station. If not, is there a backup pump? It‘s common practice of good systems to have backup pumps available to cover the times when a station pump is down for maintenance. Make sure that each station has a quick-connect fitting available on the discharge to hook up the backup pump when needed. Use the floats of the backup pump as a secondary control. Try to have multiple portable backup pumps to be moved around to cover down time, depending on the size of your utility.
Another form of backup is standby power generation. Many large lift stations will have a stationary generator available for use in power outages. Here too, portable generators are an option to move around to cover trouble spots.
After several recent storm events in the state, most of the lift station issues and spills were power-related, with spills occurring from power lost from the electrical utility going down and no power to run the lift station. In very large-scale events, the number of life stations you have on hand may need to be increased; therefore, your utility’s capital improvement plan may need additional funding to purchase more necessary equipment.
Make sure your utility joins the Florida's Water/Wastewater Agency Response Network (FlaWARN), or if you’re a small utility, join the Florida Rural Water Association; both have access to backup pumps or generators available for use in troubled times.
If the pumps in the station are not keeping up with the incoming flow over time, this means two things: the pump may be in need of a rebuild with new impellors, or the flow has increased to the station. A larger pump may be needed for the new flow capacity the station is experiencing, which can be tricky due to power and breaker requirements from an increased-horsepower pump. You can also add a third pump to the flow equation, but choose this wisely.
Now let’s look at the controls of the station. Several questions come to mind:
- Are all the floats working or set at the right level?
- Is there supervisory control and data acquisition (SCADA) monitoring for each lift station?
- Do you measure the amperage for each pump?
- Do you run trends and run time reports on each lift station?
Floats, relays, starters, and breakers are the triggers that allow the lift station to operate correctly and turn on and off to keep the station at the proper level; always ensure that they are properly sized and working correctly. Floats are to be tested regularly to make sure they operate correctly in the pump and set off an alarm at high level. The rule governing this calls for a visual (light) or audible (horn) alarm to be in place. If you in a residential area, this could get tricky with the neighbors! You can also use them to your advantage in conjunction with a SCADA monitoring system for good remote observation 24 hours a day to call out alarm conditions.
Many utilities across the state of Florida have SCADA systems in place to help with this. It’s good practice to use your SCADA system to track your run times and pump downtimes on each pump. This is a good tool, or indicator, to find problems with the station. As a pump wears out or get ragged, the run times will change. Pulling the pump and deragging it, or replacing a worn impeller, will keep the station running smoothly and efficiently. Measure and track your amperage, wet well level, and discharge flow on your SCADA system where you can. Amperage tracking, like run-pump down hours, is another tool to use to look for pump problems or issues over time. Use it to your advantage to prevent SSOs before they occur.
A very important part of issue prevention is to routinely inspect each lift station. Some questions that come to mind are:
- Does the station look and sound normal?
- Is the equipment working properly?
- Is the site secure and locked up?
- Is there grease or solids build up in the station?
- When is the last time it was pumped down or cleaned?
- Is there an unknown (unusual color or odor) contaminate coming into the lift station?
I would recommend a regular routine visit to check each station to ensure that all of these are in normal condition. If any of them are not right, then corrective action is necessary to fix the issue. A monthly pump down test and cleaning is another good way to make sure all is right with the pump station. I used to scrape down the sides of the station and wash the solids during the pump down time many years ago; now, chemical or biological degreasers are available to help in the chore. Also, jet-vac truck cleaning is another good choice today.
The monthly testing of any standby generators to operate the whole station is a great way to be sure it’s ready for the next outage. Inspections, and washes and pump downs, coupled with a SCADA monitoring system, is a recipe for trouble-free operation.
Private Lift Stations
Private lift stations are not directly your area of responsibility, but if they’re in your service area, it can be another issue to address. Checking with property owners on their lift stations and educating them about the proper ways of operation and maintenance is a good idea to prevent spills and SSOs. Knowing how many, where they are, and who the contact is, for each one in your system is another good choice for improving customer relations and for the good of the environment.
Good luck to you on your collection system operations and maintenance. I wish you continued success in a job the never stops. Many thanks go to all of you who do this routine task without failure—you are true professionals!
I encourage you to keep learning your craft by attending FWPCOA collection system or utility maintenance training classes, or the Online Institute; further information is available at FWPCOA.org or http://go.flextraining.com/FLC8518/.
2018 Short School Success
The August FWPCOA state short school was another successful training event. This was held in Fort Pierce at the Indian River State College, with over 350 student’s attaining training in many different industry disciplines and certification options. The short schools are held In March and August of each year.
I want to thank the talented individuals who volunteered their time and intellect to pass on their knowledge of the profession as instructors at the school. We have some great instructors in the state and I appreciate all who do this work. I also want to thank the training office, headed by Shirley Reaves, for the excellent job of coordination and logistics for the short school.
I commend the awards committee and Rene Moticker, our excellent awards chair, for a great job. My congratulations go to the many award winners recognized at the FWPCOA annual awards luncheon—they were all well deserved.
Lastly, I wanted to thank all the passionate and hardworking professionals who came to learn, take a class, and stay on top of their craft. Continued success to you all—never stop learning!