What Are Drainage Systems Types Working Principle and Applications in Soil Management
Drainage systems are in place to remove waste water or extra water. If we do not have a proper drainage system, it may lead to floods in the low-lying areas and hence causing damage to property and health. An improper drainage system may also cause various kinds of disease and act as a breeding ground for various insects.
What are Drainage Systems?
Drainage is defined as the natural or artificial method to remove excess water/wastewater from one place to another place through channels.
Residential Drainage System
A residential drainage system removes extra water from the residential area. This system helps whisk water away from roofs, driveways, roadways, and homes.
Types of Drainage Systems
There are mainly four types of drainage systems:
Surface Drainage System
Subsurface Drainage System
Slope Drainage System
Downspout and Gutter System
Surface Drainage System
For the surface drainage system, it is needed to dig a few ditches which are used as a funnel for excess water. With this, we can send water away from home or any area to prevent flooding.
This type of drainage system is mostly found on very flat land. It is done to prevent rainwater accumulation on a flat surface because the accumulation of rainwater on a flat surface can lead to damage to our homes.
Subsurface Drainage System
For the subsurface drainage system, we use a drain or a pipe that goes deep inside the soil. Here, we can also use a sump pump to push water through these pipes as well. These drainage systems are made to remove excess water from the soil. Plants can grow properly with this drainage system because excess water that is trapped in roots or plants can cause them to rot.
Slope Drainage System
In this drainage system, pipes are installed on an inclined surface. This makes water move naturally away from the home or any area. Pipes can be made of steel, concrete, or plastic and wrapped with a protective layer.
Downspout and Gutter System
In this drainage system, the downspout is connected to the gutter, which gets rid of excess water that builds on the roof. It is the most essential drainage system used at home. Without this system, rainwater comes off the roof and damages our house.
Open Drainage
The open drainage system utilises tail, open side ditches, and lateral and outfall ditches. The open drainage system is mostly used to collect wastewater that is not sewage. These types of drainage systems are used to dispose of sanitary waste that is highly unhygienic and unsafe.
The open drainage system is not safe to use because people can easily come in contact with this and it may cause various types of disease in people. The benefit of this type of drainage system is it is convenient to build and maintain.
Closed Drainage System
This type of drainage system forms a closed underground network. In this type of drainage system, first refuse is collected from individual areas and then transported to the main network at last goes to the treatment plant.
A closed drainage system prevents human contact with waste and wastewater. It also prevents the spreading of disease. And also does not act as a breeding ground for insects. Cleaning a closed drainage system is easier than an open drainage system.
Conclusion
The drainage system is the system used to remove waste or extra water. There are four types of drainage systems. The open and closed drainage system is also there. Closed drainage systems are better than open drainage systems. Drain systems are an important necessity in human civilization to maintain hygienic conditions.
FAQs on Drainage Systems and Their Role in Soil Chemistry
1. What is a drainage system in environmental chemistry?
A drainage system in environmental chemistry is a network of pipes and channels designed to remove and transport wastewater, sewage, and stormwater for safe treatment and disposal. It plays a key role in preventing water contamination and maintaining chemical balance in natural water bodies.
- Collects domestic, industrial, and rainwater runoff
- Prevents accumulation of pollutants
- Directs wastewater to treatment plants for chemical and biological processing
- Reduces environmental pollution and disease spread
2. What are the main types of drainage systems?
The three main types of drainage systems are combined, separate, and partially separate systems. Each type differs in how it handles sewage and stormwater.
- Combined system: Carries sewage and stormwater in the same pipe
- Separate system: Uses different pipes for sewage and stormwater
- Partially separate system: Mixes limited stormwater with sewage
3. What is the chemical composition of sewage water?
Sewage water primarily contains organic matter, nutrients, suspended solids, pathogens, and dissolved gases. Its chemical composition determines the treatment method used.
- Organic compounds (proteins, carbohydrates, fats)
- Nitrogen compounds such as NH3 and NO3-
- Phosphates like PO43-
- Dissolved gases including H2S and CO2
4. What is BOD in drainage and wastewater systems?
BOD (Biochemical Oxygen Demand) is the amount of dissolved oxygen required by microorganisms to decompose organic matter in wastewater. It is a key indicator of water pollution level.
- Measured in mg/L
- High BOD indicates high organic pollution
- Typical domestic sewage BOD: 200–300 mg/L
- Lower BOD after treatment means cleaner effluent
5. How does the nitrification process work in drainage treatment plants?
Nitrification is a biological oxidation process where ammonia is converted into nitrite and then nitrate by bacteria. It reduces toxic ammonia levels in wastewater.
- Step 1: 2NH3(aq) + 3O2(g) → 2NO2-(aq) + 2H+(aq) + 2H2O(l)
- Step 2: 2NO2-(aq) + O2(g) → 2NO3-(aq)
6. What is the role of pH in drainage systems?
The pH of wastewater controls chemical reactions, microbial activity, and corrosion in drainage systems. Most treatment processes operate efficiently at pH 6.5–8.5.
- Low pH can cause pipe corrosion
- High pH may inhibit microbial activity
- Extreme pH affects precipitation and chemical treatment efficiency
7. Why is hydrogen sulfide formed in drainage pipes?
Hydrogen sulfide (H2S) forms in drainage pipes due to anaerobic decomposition of sulfur-containing organic matter by bacteria. It is responsible for foul odors and pipe corrosion.
- Occurs in oxygen-deficient (anaerobic) conditions
- Produced by sulfate-reducing bacteria
- Causes corrosion by forming sulfuric acid (H2SO4)
8. What is COD in wastewater chemistry?
COD (Chemical Oxygen Demand) is the amount of oxygen required to chemically oxidize organic and inorganic matter in wastewater. It measures total pollutant load.
- Expressed in mg/L
- Usually higher than BOD
- Determined using strong oxidizing agents
9. How are phosphates removed from drainage water?
Phosphates are removed from wastewater by chemical precipitation or biological treatment to prevent eutrophication. Chemical removal involves forming insoluble salts.
- Addition of aluminum or iron salts
- Example reaction: Al3+(aq) + PO43-(aq) → AlPO4(s)
- Precipitate is removed by sedimentation
10. What is the difference between stormwater and sewage in drainage systems?
The main difference between stormwater and sewage is their chemical composition and pollution load. Stormwater mainly contains runoff contaminants, while sewage contains high organic and nutrient content.
- Stormwater: Rainwater mixed with soil, oils, and debris
- Sewage: Domestic/industrial wastewater rich in organic matter and microbes
- Sewage requires intensive chemical and biological treatment
