7.1 Types of Sanitary Systems Explained
Key Concepts
- Municipal Sewer Systems
- Septic Systems
- Combined Sewer Systems
- Separate Sewer Systems
- Stormwater Drainage Systems
- Graywater Systems
- On-Site Wastewater Treatment Systems
Municipal Sewer Systems
Municipal sewer systems are centralized networks that collect wastewater from homes, businesses, and industries and transport it to treatment facilities. These systems are typically managed by local governments and include both sanitary and storm sewers.
Example: A city with a network of underground pipes that carry wastewater to a central treatment plant.
Analogy: Think of a municipal sewer system as a "community trash collection service" that picks up waste from every household and takes it to a central disposal site.
Septic Systems
Septic systems are decentralized wastewater treatment systems used in areas without access to municipal sewers. They consist of a septic tank, where solids settle and decompose, and a drainfield where treated wastewater is dispersed into the ground.
Example: A rural home with a septic tank and drainfield in the backyard.
Analogy: A septic system is like a "personal waste disposal unit" for a home, processing and disposing of waste on-site, similar to how a compost bin breaks down organic material in a garden.
Combined Sewer Systems
Combined sewer systems collect both sanitary sewage and stormwater in the same pipe network. During heavy rains, the system can become overwhelmed, leading to combined sewer overflows (CSOs) that discharge untreated wastewater into water bodies.
Example: An older city with a single pipe network that carries both household waste and rainwater to a treatment plant, with overflow structures in place to manage heavy rainfall.
Analogy: Consider a combined sewer system as a "dual-purpose highway" that handles both regular traffic and emergency vehicles, but may become congested during peak times.
Separate Sewer Systems
Separate sewer systems have distinct networks for sanitary sewage and stormwater. This separation prevents overflow issues and ensures that each type of wastewater is treated appropriately.
Example: A modern city with two separate pipe networks: one for household waste and another for rainwater.
Analogy: Think of separate sewer systems as "dedicated lanes" on a highway, with one lane for regular traffic and another for emergency vehicles, ensuring smooth and efficient flow.
Stormwater Drainage Systems
Stormwater drainage systems are designed to manage rainwater and surface runoff. These systems include gutters, downspouts, and underground pipes that direct water away from buildings to prevent flooding.
Example: A commercial building with gutters and downspouts that direct rainwater into underground pipes leading to a storm sewer system.
Analogy: Consider a stormwater drainage system as a "water evacuation route" that quickly removes rainwater from your property, similar to how a drainage ditch prevents water from pooling in a field.
Graywater Systems
Graywater systems collect and treat wastewater from sources such as showers, sinks, and laundry, which is then reused for non-potable purposes like irrigation and toilet flushing. This system conserves water and reduces the load on sewer systems.
Example: A residential home with a graywater system that collects water from the shower and uses it to water the garden.
Analogy: Graywater systems are like "recycling bins" for water, collecting and reusing water that would otherwise be discarded, similar to how recyclables are collected and reused.
On-Site Wastewater Treatment Systems
On-site wastewater treatment systems, such as advanced septic systems, provide more sophisticated treatment of wastewater on the property where it is generated. These systems can include aerobic treatment units, sand filters, and disinfection processes.
Example: A rural home with an advanced septic system that includes an aerobic treatment unit to improve wastewater treatment.
Analogy: Think of on-site wastewater treatment systems as "personal water treatment plants" that process and clean wastewater on-site, similar to how a home water filtration system purifies drinking water.