Wastewater Treatment and Disposal

There are lots of things that pollute our water from stormwater, to farm runoff to commercial and industrial waste. One pollution source we all contribute to is poop, in less potty term, sanitary waste, the waste coming from our toilets, sinks and showers. 

We typically treat sanitary waste in two ways, at home through septic systems or through a municipal or county wastewater treatment plant.  The two systems treat waste very similarly in the beginning, by separating the liquid material from the solid material in the waste. 

Home Septic Systems

Septic systems do this via a settling tank, where waste sits and allows sludge (solid material, like toilet paper and poop), scum (grease, fat and other floatables) and effluent (liquid waste) to separate.  Septic pumping companies service residential systems to make sure the systems are cleared and function properly over time.

In septic systems, wastewater (without solids) drains via gravity from the tank into perforated pipes in the drainage field in the ground. The micro-organism in the soil treat the wastewater, removing organic dissolved material and harmful bacteria. The field consists of pipes, gravel or sands, typically covered with soil and grass.

If a septic system is not maintained properly, it may fail to treat the wastewater allowing harmful pathogens into the groundwater. In addition, septic systems may also add excess nitrogen to groundwater, which may be harmful to humans or lead to excess algae growth in streams, lakes and rivers.

Sewage and Wastewater Treatment Plants

Wastewater treatment plants work in a similar manor with settling tank called a quiescent basin or primary sedimentation tanks, this process is called primary treatment stage of treatment systems.

After the sludge is removed from wastewater treatment plants, and stabilized by anaerobic digestion and composting, it is bio-solids and be reused.  Many times, the bio-solids are repurposed as fertilizer.  The next step in treatment at a Wastewater Plant, is called Secondary Treatment and involves using the anaerobic biological processes of bacteria and protozoa. The bacteria and protozoa consume the biodegradable soluble organic contaminants, dissolved organics in the effluent. For this to occur properly bacteria and protozoa need a balance environment with enough oxygen and “food” to stay happy and healthy.  

Tertiary treatment process is aimed at removing nutrients and other remaining contaminants, such as nitrogen and phosphorus from the effluent. The Treatment can consist of many different processes such sand filtration, ponds, biological oxidation and denitrification, enhanced biological phosphorus removal, or disinfection through chlorination, UV light or ozone.

Water released from both septic systems and waste water treatment plants should be treated to limit the negative impact on the river and groundwater it is released in to.