How Does a Septic System Work?

Summary

This video explains how septic systems work, focusing on the function of septic tanks in treating wastewater. The process begins with solids settling in the primary compartment, while fats and oils form scum at the surface. Treated effluent then flows to a distribution box, where it is distributed to trenches that allow for further treatment in the soil. Gases produced during digestion exit through roof vents, and proper maintenance, including regular pumping, is essential for system longevity and environmental protection. Understanding septic systems is vital for public health and effective waste management.

Takeaways

• 🛠️ Septic systems are widely used for wastewater treatment in millions of homes across the United States.
• 🏠 A septic tank has two compartments that capture both solids and liquids for treatment.
• 🔄 Wastewater flows into the primary compartment before moving to the secondary compartment through a partition opening.
• ⚖️ Solids settle at the bottom of the tank, while fats, oils, and greases float to the surface, creating scum.
• 🚧 The baffle wall in the septic tank prevents solids from leaving the tank and entering the disposal field.
• 💨 Gases produced from anaerobic digestion and from the disposal field fill the air space above the liquid and exit through roof vents.
• 🌊 Treated wastewater, or effluent, is distributed to trenches via a distribution box, where it trickles over gravel beds.
• 🌱 The effluent infiltrates the soil, promoting plant growth through a process called evapotranspiration.
• 🧹 Septic tanks should be pumped every three years to remove solids and maintain system health.
• 🌍 Understanding septic systems is crucial for their proper design, installation, operation, and maintenance to protect public health and the environment.

Q & A

What is a septic system?

A septic system is a method of waste treatment commonly used in homes, primarily to treat wastewater and manage sewage.

How does a septic tank function?

A septic tank captures both solids and liquids, allowing solids to settle at the bottom while liquids flow into a secondary compartment before being discharged to a disposal field.

What happens to solids in a septic tank?

Solids settle at the bottom of the primary compartment, while smaller amounts may move into the outlet compartment, but most solids are retained due to a baffle wall.

What is scum in the context of septic tanks?

Scum refers to fats, oils, and greases that accumulate on the water's surface in a septic tank.

How do gases behave in a septic tank?

Gases generated from anaerobic digestion and those entering from the outlet pipe accumulate above the liquid and expand outward through the inlet pipe, exiting through the home's roof vents.

What is the role of the distribution box in a septic system?

The distribution box distributes treated wastewater or effluent from the septic tank to multiple trenches for further treatment and filtration.

What is a biomat, and why is it important?

A biomat is a layer that forms at the trench bottom over time, thickening to prevent water flow and promote nutrient uptake by plants through evapotranspiration.

How often should septic tanks be pumped?

Septic tanks should be pumped every three years to remove solids and liquids, although some essential material is always left to maintain healthy biological levels.

What is the significance of understanding septic systems?

Understanding septic systems is crucial for proper design, installation, operation, and maintenance, which helps protect public health and the environment.

What is evapotranspiration in the context of septic systems?

Evapotranspiration is the process through which additional water moves upward through soil pores, providing nutrients to plants and promoting their growth.