Entex recently received purchase orders for two lagoon upgrades, one in West Virginia and one in Louisiana. Despite their similarities in flow, size, and effluent requirements, the best process solutions for the two lagoons are not the same due to differences in climate and topography. The lagoon in Louisiana stays quite warm throughout the year and can achieve its goals with an aeration-only approach using Entex’s Octopus^TM floating aeration system. The lagoon in West Virginia however, experiences very cold winter conditions as it is located deep in the mountains. Therefore, this plant had no choice but to supplement its biomass inventory by using Entex’s WavTex^TM fixed-film modules. Similar to the Louisiana project, the West Virginia lagoon is also using our Octopus system for supplemental aeration.

The following table shows the design considerations and scope of supply for each system, comparing and contrasting the two.

The two lagoons have quite similar influent flows and compositions as well as effluent limits. While the West Virginia lagoon does have a longer HRT, as a result of its larger volume, the colder weather drove the need for the additional fixed biomass. Not only do the WavTex units provide this additional biomass inventory, but the warm air from the blowers creates a warmer environment for the fixed-phase biology, maintaining nitrification rates even at low bulk liquid temperatures.

For both lagoon systems, all of the equipment will be floated. Both the Octopus aeration units and the WavTex units are 9 feet in depth from the water level to the bottom of the units. With only one foot between the diffusers and the lagoon floor, the oxygen transfer efficiency is optimized and the surface area of the EnTextile media sheets is maximized.

Submittals and equipment fabrication are ongoing for both projects with installations planned for the summer. We’ll keep you apprised of the results of both upgrades after start-up.