What Does Wastewater Treatment Do?

wastewater treatment package plant installation

Wastewater treatment uses natural biological processes to protect the environment from contaminants in sewage.

Wastewater poses several threats to the environment. Micro organisms which digest the suspended organic matter (Total Suspended Solids – TSS) in sewage use up the dissolved oxygen (DO) present in the water. The rate of this digestion can be measured as Carbonaceous Biological Oxygen Demand (CBOD). Water with high CBOD can deplete dissolved oxygen in waterways thereby suffocating wildlife.

septic tank cutaway
A common septic tank design

All wastewater treatment from septic tanks to municipal systems use gravity to settle out most solids. After settling, smaller organic particles remain suspended in the effluent. The settled wastewater then moves into biological treatment which increases the density of micro organisms in an oxygen rich environment. When done properly, biological treatment can neutralize the oxygen depleting effects of wastewater.

Wastewater treatment also removes chemical pollutants.

infographic of nitrification and denitrification in wastewater
Conversion of ammonia to nitrate and nitrate to nitrogen gas in wastewater.

One byproduct of human metabolism, ammonia, can poison watersheds through untreated sewage. Beneficial bacteria naturally occurring in wastewater use DO to convert toxic ammonia into the nutrient, nitrate. That’s good, but not quite good enough. When nitrate along with another nutrient, phosphorus, enters the environment, they can cause plant overgrowth that chokes waterways. Conveniently, other wastewater bacteria turn nitrate into nitrogen gas and mineralize phosphorus which settles out of the resulting effluent.

cutaway of an aerobic wastewater treatment plant

These bacteria multiply into a slime layer called, “biofilm” in the biological reactor. Advanced treatment systems achieve high biofilm density by giving it a lot of surface area (media) to grow upon. The greater the surface area, the higher the treatment level.

Aqua Tech uses the latest in biofilm media technology to achieve maximum treatment in a very small treatment plant.

Wanna know more about wastewater or how we can take care of it for you?