Wastewater systems are treatment systems that collect, treat, and dispose of wastewater generated by homes or businesses. The wastewater is treated on site, rather than collected and transported to a centralized community wastewater treatment plant. In the article below you will learn about different wastewater systems and how to properly care for them.
Wastewater System Descriptions
Conventional System (Class 1):
This type of system consists of two main parts; a septic tank and a disposal field. The septic tank is a watertight tank that works to separate solids from liquids. Effluent filters placed on the outlet of the septic tank help prevent solids from leaving the tank and going to the disposal field, slowly plugging the field. The disposal system receives partially treated liquid effluent from the septic tank via gravity or pump. The size of the drain-field is determined by the amount of wastewater flow anticipated and the quality of the soil below. Disposal systems vary from trenches, beds, drip systems and other means of disposal.
Secondary Systems (Class 2):
Secondary systems are most commonly aerobic units, which replace or work with septic tanks. Aerobic units add oxygen to wastewater, which converts ammonia (NH3) to nitrate (NO3) and nitrite (NO2) liquid effluent. These units substantially reduce BOD (biological oxygen demand) and COD (chemical oxygen demand), thereby reducing biomat (microbial material that can clog the pores of the soil or gravel in the drain-field) build up in disposal systems and adding longer life to a disposal system.
Tertiary Systems (Class 3):
Tertiary systems reduce nitrogen (known as de-nitrification) in the liquid effluent to acceptable levels. De-nitrification can occur in wetlands when plants uptake and use nitrogen or a sequential batch reaction (SBR) which works like a small waste-water treatment plant. De-nitrification is necessary when groundwater needs to be protected from nitrate (NO3) contamination.
Disinfecting the effluent is needed to kill harmful bacteria and must be done when there is shallow groundwater or shallow bedrock. This is because bacteria in these conditions will most likely get into groundwater and contaminate it. There are different types of disinfection units; the most common are chlorine capsules and UV light units