Introduction
The science of sewage disposal is perhaps the most helpful in managing diseases. By eliminating wastes carried by water, such as minute dissolved materials, solid matter like human excreta, toxic chemicals, and bacteria, sewage disposal protects a society's water supply. Constructing septic tanks to collect human waste is one possibility for making the arrangement for sewage disposal.
Human excreta disposal is ultimately converted into over time. The composting pits can store waste and turn it into manure. To transport sewage from the gathering site to the discharge, the collection of sewage systems is set up with pipelines, manhole outlets, storing basins, catch basins, inlets, and pump stations. To create usable biogas, sewage can be gathered in biogas plants. Chemical toilets can be built because they are pollution free and don't need a lot of water for human excreta disposal. These restrooms are perfect for trains.
What is Sewage Disposal?
Waste water is all that sewage entails. Sewage includes complex mixture of saprophytes, bacteria, microorganisms, organic and inorganic impurities that cause several disorders. Previous to being released back into the environment, sewage systems collect and purify the wastewater. Such systems are made up of complex sewers networks that transport sewage from the place of collection through the treatment method.
Rainwater management is also handled by sewage systems, either independently or as a single system. Rainwater is frequently allowed to enter the streams in different networks untreated since it is thought to be generally clean. Whenever there is no sewerage infrastructure, commonly two alternate arrangements for sewage disposal are applied like:
Septic tanks and other inexpensive on-site sanitation systems.
Composting restrooms: This is a dry restroom. Excreta, which lacks both water and odour, is handled through aerobic breakdown in this method.
Types of Sewage
Typically, there are three types of sewage:
Industrial Sewage
Polluted water from chemical or production process is carried by the industrial wastewater. Such sewage may contain a variety of pollutants, including chemicals. This wastewater is primarily generated by industries; hence it may be hazardous and heavy metal-contaminated.
Domestic Sewage
The leftover water from residences or apartments is referred to as domestic wastewater. Sanitary sewage is another name for this kind of sewage. Bodily waste or bathing water runoff are both possible causes. Our homes produce this wastewater every day as a result of routine domestic tasks.
Storm Waste
Stormwater refers to the wastewater overflow from the environment that collects as water droplets in open channels. This could involve snow, rain, or mist. Over 99.9% of all wastewater is made up of residential sewage. Domestic wastewater often contains hazardous organisms, despite the fact that plant nutrients and organic matter are identified as the main pollutants. The nutrients that can be recovered following sewage treatment are present in this effluent.
Sewage Treatment Methods
Different wastewater treatment techniques can be used to remove the contaminants like chemicals and sewage like organic materials, suspended sediments, plant nutrients, microorganisms, etc. from the wastewater, which is then recycled for additional uses. The following table lists the four sewage treatment methods:
The fundamental elements of a sewage management system are sewage disposal procedures. It disposes off the spent water from homes, businesses, etc. and improves the environment's cleanliness. Municipal systems, off-site/on-site sewer systems, lagoons, and septic tanks are a few of the established sewage system disposal techniques used all over the world. The municipal wastewater system makes use of treatment facilities that are linked to the wastewater supply.
After treatment, extra water from an off-site sewage system is sent towards a neighbouring river or irrigated area. Utilities including septic tanks, septic drainage fields, chemical toilets, and composting pits are included in the on-site or septic sewage system. A complete sewage disposal system collects the wastewater from homes and directs it to several sewer lines, thereby, reduces the volume of solid waste. Huge open pools known as lagoons are capable of collecting the sewage from homes, and pit lavatories are the century-old sewage disposal practice that are used in human civilization.
Sewage Collection Methods
Many underground canals are routinely used in sewage system design to transport the wastewater released by municipalities. Sewage can be moved from the collection point to disposal by using the collection system's pipes, manhole outlets, hold basins, etc. There are primarily two ways to collect the sewage, such as:
Combined System - built generally with large-diameter pipelines or tunnels. It transports both household and storm sewage.
Separate System - which transport household and storm wastewater in separate streams.
Interesting Facts
A higher impact is made by sewage discharges and the pollution that arises from them rather than by the water used in manufacturing. Over the course of the world, 80% of wastewater is simply returned back into the environment.
Key Features
The purpose of sewage treatment is to create an outflow that can be released into the environment with the least amount of water contamination, that can be recycled in a beneficial way.
To reduce the risks to human and aquatic life, sewage disposal systems contain authorised facilities for the treatment of sewage, like sanitary drainage systems, leaching pits, etc.
The most widely used sewage treatment techniques include physical, biological, chemical, and sludge drainage treatments.
FAQs on Alternative Arrangement for Sewage Disposal
1. What are the main alternative arrangements for sewage disposal in areas without a proper sewerage system?
In areas lacking a centralised sewerage network, several on-site alternative arrangements are used for sewage disposal. The most common methods include:
- Septic tanks: These are underground chambers that collect wastewater, separate solids from liquids, and use anaerobic bacteria to decompose the solid waste (sludge).
- Chemical toilets: These are self-contained, portable toilets that use chemicals to disinfect waste and reduce odours.
- Composting pits: A simple method where a pit is dug to dispose of human excreta, which is then covered with soil and turns into compost over time.
- Vermi-processing toilets: An eco-friendly method that uses earthworms to treat human excreta, converting it into valuable vermi-cake fertiliser.
2. How does a septic tank work as a method of sewage disposal?
A septic tank is a primary wastewater treatment system that works in a few simple steps. Wastewater from the house flows into the tank, where heavy solids settle at the bottom to form sludge, and lighter materials like grease float to the top as scum. Inside the tank, anaerobic bacteria (bacteria that live without oxygen) digest the sludge, reducing its volume. The partially treated liquid, called effluent, then flows out of the tank into a drain field or soak pit for further natural purification in the soil.
3. Why are alternative sewage disposal systems necessary, especially in rural areas?
Alternative sewage disposal systems are crucial in rural or sparsely populated areas primarily due to the lack of infrastructure. Laying down extensive networks of underground sewer pipes (sewerage) is extremely expensive and not practical for locations with few houses spread far apart. On-site systems like septic tanks provide a cost-effective, self-sufficient, and efficient way to treat household sewage, preventing the contamination of groundwater and reducing the risk of waterborne diseases like cholera and typhoid.
4. What is a vermi-processing toilet and why is it considered an eco-friendly option?
A vermi-processing toilet is a type of toilet that uses a specific species of earthworms to treat human excreta. The waste is broken down and converted by the worms into vermi-cake, which is a high-quality, nutrient-rich fertiliser. This method is considered highly eco-friendly because it requires very little water, does not cause pollution, and converts a waste product into a valuable resource for agriculture. It is a sustainable solution for low-cost sanitation.
5. How is a chemical toilet different from a standard septic tank system?
A chemical toilet and a septic tank differ significantly in their mechanism, permanence, and application. A chemical toilet is a portable, temporary unit that uses strong chemicals to disinfect waste and control odours, storing the waste in a holding tank that needs to be emptied regularly. In contrast, a septic tank is a permanent, underground installation that uses natural biological processes (anaerobic digestion) to treat wastewater continuously, with the liquid effluent being discharged into the surrounding soil for further filtration.
6. What are some potential problems that can arise with on-site sewage disposal systems?
While effective, on-site systems can have problems if not properly maintained. Key issues include:
- Clogging: Septic tank drain fields can get clogged with solids if the tank is not pumped out periodically.
- Contamination: A poorly designed or failing system can leak untreated sewage into the groundwater, contaminating wells and local water sources.
- Odour: Improper functioning or lack of ventilation can lead to unpleasant smells.
- Chemical Interference: Flushing harsh chemicals or non-biodegradable items can kill the essential bacteria in a septic tank, halting the treatment process.
7. Why is it unsafe to directly dispose of untreated sewage into rivers or fields?
Disposing of untreated sewage directly into the environment is extremely dangerous. Untreated sewage is a complex mixture containing harmful substances, including disease-causing microorganisms (like bacteria and viruses), organic impurities, and toxic chemicals. When this enters rivers, it contaminates the water, making it unfit for drinking, bathing, or agriculture. It can lead to widespread outbreaks of waterborne diseases such as jaundice, cholera, and dysentery, and it severely harms aquatic life by depleting oxygen in the water.
