How to take a 24-7 wastewater treatment plant offline
There’s no switch for this
At South Fort Collins Sanitation District (SFCSD) we would like to make one thing clear: there are no off days in our business. The water that needs treating does not stop and there is no faucet to turn off or switch to hit that will let us clock out for the weekend.
No, in our business it is 24-7, 365 days a year and if we take a day off treating water things can go really bad really quick. However, that does not mean that we don’t take our facility offline. When we have major construction to tie-in new equipment, like with our recent plant expansion, we take the facility offline in a safe, planned manner to ensure there is no impact to the high-quality wastewater treatment you receive. So how do we do it?
First, we plan ahead and pick a low flow time of day, typically between 2 a.m. and 7 a.m., and keep a lot of staff running on coffee and adrenaline. There are some areas of the facility that always need power, so we use portable generators to power those critical buildings. These include the main pumping building, computer network, portable lighting for performing work and power tools.
Next, we make sure there is room in the process to store any flows that do come in during that time frame. We keep an empty tank to store flows while the power is out. At the same time, we stop discharging prior to turning off power to safeguard our downstream waters. Safety is paramount during this process. This work requires an excellent safety program and staffing that ensures proper lockout or tag out to protect personnel.
Finally, taking our treatment plant offline requires lots of coordination. We communicate with the power company and contractors to keep them in the loop the entire time. We also use radios and cell phones to communicate the entire time and coordinate the shutdown with people on standby working on the critical equipment. You can not really overcommunicate something like this.
And with that in mind, we always make sure to have two of everything because there is no time to chase down parts or tools during the shutdown. Redundancy is key to keeping things safe and on track. We are always prepared for anything. Scout’s honor!
Our shutdowns are typically planned and also happen infrequently. However, if there were ever a temporary power outage, we have measures in place to ensure we are fully operational again within 30-seconds using our backup generator systems. We have worked hard to design redundancy into the entire facility so individual items can go offline with little to no impact to the rest of the plant.
Make it count
It’s not often that we take the treatment plant offline so one thing is for sure; we want to use this rare opportunity to perform work that cannot otherwise be performed. This means opening electrical gear for cleaning and maintenance. Once the electrical source has been disabled and locked out, we are also able to inspect equipment, channels and tanks that were never designed to come out of service. It is a rare opportunity and we do not want to squander it.
You may not know that our treatment process mimics the natural process that exists in lakes and streams, meaning we use naturally occurring bacteria breakdown the waste products. As you’ve probably guessed you can’t stop mother nature. However, the biology in the plant is resilient and can handle short-term interruptions and recover very quickly with no issues from the lack of oxygen and mixing. We make sure to protect what we call our “workhorses” with careful planning and limiting the duration of any process changes.
Our number one priority when we shutdown is protecting our receiving water. If a shutdown were to cause us to not be able to sufficiently treat the water, we will make sure to store the flow on-site in additional tanks until everything is restored and the proper high-quality treated effluent can be released within the guidelines of our discharge permit.
The bottom line here is that all the water is still safe when it leaves our facility. We continue receiving during the entire process, which means no impact to you. This is thanks to the work we do in advance with staff, contractors and consultants to ensure customers are taken care of with no interruptions in service or inconvenience at all.
If we are doing our job right, you’ll have no idea that anything happened on our end.
Check twice, then check again
Once power is restored our work is far from done. We have to follow a series of steps and safety checks to ensure everything is back in working order.
This means verifying and double-checking all equipment and operations in every building and reviewing every process. That requires multiple people working their way throughout the entire facility.
It is no small feat, but it is necessary to ensure everything is safe. Once everything is operational again then we are able to restore normal process flows and monitor throughout the day. After a shutdown, we always pay extra attention to verify the entire treatment process recovers quickly and we maintain an excellent product of clean safe reclaimed water.
The last thing to do? Reset the clock on the microwave of course!
While we have never had to shut the plant down unexpectedly, and hope we never have to, these planned “test” runs are great practice for our team and ensure that we can handle whatever comes our way so you, our customer, stay safe.