Still, the solid matter taken out of the treated wastewater at the Agingan wastewater treatment plant in San Antonio has some value.
Whatever stays in the wastewater that runs from household septic tanks to the Agingan sewer plant will regain its worth after going through a series of treatment process that includes sedimentation, aeration and polymer treatment.
According to Agingan sewer plant’s lead man Jeff Reyes, the clay-looking sludge is ideal for organic fertilizer.
Because the density of its nutrient content is very strong, a handful of this sludge is enough to keep the soil around your plants healthy.
Agriculturist Isidoro T. Cabrera agrees. He said the use of Agingan sludge is allowable but it has to be dried first.
Saipan farmers have been using it for many years for their farm plots because it is very effective in improving soil structure and texture, said Cabrera who also uses it on his own farm.
He said the sludge works best on vegetables, shrubs, trees, and flowering plants.
This organic fertilizer, which is very rich in nutrients, is tilled with the soil to benefit the crops.
The amount of sludge “produced” by the Agingan sewer plant varies, according to Reyes.
“It depends on the number of times we operate the plant,” which, in turn, depends on the “sludge depth,” he added.
Reyes said they measure the depth or thickness of the solid matter that settles at the bottom of the tanks.
Once a certain height of the sediment is reached, they discharge the wastewater to another tank, and then to another tank before it goes to the polymer tank where they mix it with 50 pounds of polymer powder to separate the solid matter from the water.
During this operation, Reyes said they can produce up to 30 to 40 cubic yards of sludge which they temporarily store at the northern side of the plant.
It’s not that stinky, he added.
Two years ago, the previous operators of the sewer plant told Variety that farmers and gardeners came to the place to get pails of sludge.
But now, Reyes said, they no longer allow that.
There is proper testing that needs to be done in order for them to officially allow the use of sludge for agriculture or gardening use.
The testing is costly and available only off-island.
For now, Reyes said the sludge is disposed at the Marpi landfill where farmers can get it.
