CITY OF CUMMING, GA

WASTEWATER TREATMENT PLANT

The City of Cumming, GA needed to expand their wastewater treatment plant to handle a Peak Daily Flow of 20 MGD. The City’s consulting engineer, Civil Engineering Consultants, started looking at process equipment to include in the design for the expansion.

The search for grit and grease removal equipment was fairly easy since the existing plant already had a Schreiber Grit and Grease removal system at the head of the plant. The existing system had a proven performance and track record for several years. Civil Engineering Consultants looked at the land available for the headworks portion of the project and determined that parallel grit and grease channels would fit the site the best. 

Schreiber uses air to agitate the waste stream so that grit will separate from the organics well. The long rectangular channel design assures that the detention time and rolling effect created by the air allows for the best removal of grit. Grit then settles to the bottom of the grit channel and is removed via a grit pump to the grit classifier. The flow into the grease channel is quiescent so that the grease can rise to the surface of the channel. Air lances are positioned above the water surface and air is directed towards the surface to move the grease down the channel to the auger extraction point. The new Schreiber Grit and Grease parallel channel design was selected and is performing well.

The engineer and owner decided to move away from chlorination/de-chlorination disinfection that was currently being used at the existing facility. UV disinfection was determined to be the best solution for the new fecal disinfection standard of less than or equal to 23 fecal coliform/100 ml based on a 30 day geometric mean.

Civil Engineering Consultants researched the various UV systems on the market and invited Trojan Technologies to provide a proposal for Cumming. Trojan’s approach to the solution not only included anefficient UV disinfection system design, but also included local service and parts availability in Georgia, as provided by the local factory trained equipment representative, Templeton & Associates Engineering Sales and TEMSCO. Trojan’s proposal was selected as the best approach and included in the plant expansion.

 

The Trojan 3000Plus UV system is a horizontal lamp configuration installed in a two channel design that uses low pressure, high intensity amalgam lamps. A patented mechanical/chemical in channel lamp cleaning system is used and was one of the key design features of the Trojan 3000Plus UV system that the engineer liked over the other proposed UV systems.