Wastewater Controls for Cold Storage
AMPS recently completed a control system design, build and installation for a wastewater controls application. We have lots of experience with municipal wastewater and some experience with industrial wastewater but this particular industrial application was new to us. It involved treating the wastewater at a facility that processes and handles raw meat such as beef, chicken and pork.
One of the main things we learned is rotting meat stinks. It really stinks. In fact, we’ve never worked in an environment more hostile to the human olfactory sensing system. Halfway through startup a contractor accidentally turned on a pump that caused about fifty gallons of untreated rotting meat water to be spilled on the floor. Experienced workers bolted for the doors and inexperienced workers wondered why it was a big deal. The odor traveled slowly but it eventually hit everyone and caused spontaneous vomiting. Seriously, this was no joke. We weren’t able to return to work for four hours!
Thankfully, we were able to return to work and pick up where we left off and the project ended up being a great success for AMPS.
Dissolved Air Flotation (DAF)
There were many components to this system but, at its foundation, was a dissolved air flotation device. There are lots of solids and suspended matter in the wastewater for this cold storage facility and these cannot simply be sent to the sewer. The main purpose for the system is to remove solids, dry them and send them away while only directing liquid to the sewer system.
Dissolved air flotation (DAF) works by injecting air under pressure to a tank which holds the untreated wastewater. The released air forms tiny bubbles which stick to the suspended solids in the tank. The bubbles rise to the surface and bring the solids with them. Now that the solids are at the surface, a skimmer can push them into a separate tank. It might not smell great but the process is really pretty cool.
Wastewater Controls Objectives
This wastewater controls project included several components. Some of the goals were:
- Monitor waste level in lift station tank outside the main building and pump it, as necessary, to the wastewater plant
- Periodically back flush a filter in the line feeding the plant
- Circulate wastewater in an equalization tank to maintain proper flow using PID
- Control speed of chemical pumps
- Fill the DAF unit as needed
- Operate skimmer on the DAF
- Monitor level of sludge coming off the DAF
- Control pumping of sludge out of the building
Wastewater Controls Solution from AMPS
We are happy to say we accomplished all the objectives for this customer, Cloverleaf Cold Storage in Napoleon, Ohio. We designed the system around the UniStream series of PLC + HMI from Unitronics. This PLC has served us well in many industries on dozens of projects.
Some of the features we utilized for this particular wastewater controls project are:
- Integrated PLC and HMI (15″ color touch-screen)
- Modbus TCP communication with the lift station
- Analog outputs to control various VFDs
- Control digital outputs for hardware such as pumps and valves
- Control analog outputs for modulating valves as part of PID
- Alarm functions triggering email and text messages sent to the plant manager
- Trending of flows and liquid levels
- Flow data logged to SD card and available to the customer and the Ohio EPA
- Remote access for monitoring and troubleshooting. The plant manager has full access at all times from anywhere in the world with internet access.
Complete Wastewater Controls Package
AMPS helped with every aspect of this wastewater controls project. We designed the electrical system, built the control panels in our UL508A panel shop, programmed the PLC and HMI, and assisted with on-site start-up.
Can we discuss your industrial wastewater project with you? We have engineers ready to help you.