As the supernatant leaves the clarifiers it is pumped to the land application as effluent. In turn, the treatment plant’s effluent then becomes influent to the Land Application System (LAS). This treated wastewater is stored in holding ponds for irrigation. Although this water has received secondary biological treatment, there remains a concentration of nutrients. The nutrients of concern are particularly nitrogen and phosphorous, which are two of three main ingredients of fertilizer. The tertiary land treatment process is then set to take place.
See the Land Application Sytem department for more details.
As the nutrient rich water is irrigated within a forested system, trees and vegetation uptake the nitrogen and phosphorous as a result of their growing process. Residual water receives its final filtration as it percolates through the soil medium.
Finally, the water reaches the subsurface groundwater table.
A byproduct of this nutrient removal process is the crop that is used for uptake. Trees can ultimately be harvested as a
timber crop and replanted as a renewable resource that can efficiently uptake these nutrients.
Irrigation takes place with 400 HP pumps and delivered through 100 miles of piping and over 9,000 solid set sprinklers.
There are over 2000 managed acres with over 1200 acres under irrigation.
The land treatment process is used rather than direct discharge to a stream. Slow rate irrigation allows plant material to uptake nutrients and the soil provides a filtering process prior to discharge to the groundwater table.