City Completes Project to Improve Efficiencies, Ensure High Level of Service at D.B. Lee Water Reclamation Facility
The City of Melbourne has recently completed a 20-month renovation of key components of the David B. Lee Water Reclamation Facility. General improvements were made throughout the plant, including the installation of new equipment to improve energy efficiency, construction of new structures, and an expansion of the plant’s laboratory. The plant treats about 4.5 million gallons of wastewater a day, with a capacity of 7 million gallons a day. These investments in the plant will help to ensure it will continue to provide consistent, reliable service to Melbourne’s current residents while accommodating future growth of the city.
Improved screening equipment has been installed to filter out non-biodegradables, including wipes, from the wastewater as it comes into the plant. Though often marketed as “flushable,” these wipes do not biodegrade the way that toilet paper does and can clog pipes inside the plant. The cylindrical mass here is made up of hundreds of these wipes removed by the screen.
Another new piece of equipment removes grit and sand from wastewater as it comes into the plant. Grit and sand can enter underground pipes that have settled over time. Removing this grit on the front end of the wastewater treatment process will eliminate the need for costly, labor-intensive removal of the grit from treatment tanks in the future.
An accumulation of grit and sand over four years had almost filled the left side of this treatment tank. It took 26 dumpsters to remove all of the grit that had accumulated here. This effort will not be necessary in the future because the grit will now be removed as it comes into the plant by the new equipment installed as part of the renovations.
This new tank was added to help reduce the amount of nitrogen in re-use water.
New automated aerators and motors were installed in this existing tank to improve efficiency.
The aerators are automated to increase and decrease speed as necessary. The flow into the plant is much lower during the overnight hours than it is in the daytime. Controls like this one monitor the amount of oxygen in the wastewater and adjust the aerator’s speed as necessary. Decreasing the aerator speed extends the life of the equipment while saving electricity.
Four Variable Frequency Drives (VFDs) were installed to allow the motors that operate both the aerators and a new pump station to increase and decrease in speed as needed, which helps to save electricity.
Two of the plant’s clarifiers were rehabilitated with state of the art collection systems, making them much more efficient.
This tank was upgraded and put into use as a Flow Equalization Tank. When wastewater flow volume is high (in the middle of the day, for instance) some of it is diverted to this tank where it is stored until flows into the plant decrease (usually in the overnight hours). When the flows are low, the wastewater in this tank is then returned for treatment. This helps keep the system running at a consistent level 24 hours a day versus running at very high levels during the daytime and low levels at night, helping to improve efficiency at the plant.
Exhaust systems were replaced and upgraded on both back-up generators. Staff is currently working with FPL to bring D.B. Lee into FPL’s Commercial Demand Reduction (CDR) program, which will enable the City to save approximately $5,000 a month in power bills. Read more about the CDR program here: https://www.fpl.com/business/save/programs/demand-response.html
In addition to expanding and renovating the lab, two new structures were built. The one pictured on the left is for the safe storage of materials, rolling stock, and back-up equipment. The one on the right is used to safely cover containers holding solids before they can be removed for land application at State permitted sites (generally pasture land or sod farms).