Sewage Characterisation

Sewage is wastewater ejected by offices, hospitals, houses, industries, and other users in the sewers. Rainwater that flows down the run during heavy rainfall or a storm also goes into the sewage system. The sewage’s suspended solids, organic and inorganic impurities, nutrients, saprophytes, and bacteria that cause disease and other microbes are a complex mixture.

Composition of Sewage

• Organic impurities: Animal faeces, human waste, petroleum, pesticides, herbicides, urea (urine), fruits and vegetables trash, etc.
• Inorganic pollutants: Phosphates, metals, nitrates.
• Nutrients: Phosphorus and nitrogen.
• Bacterial waste: Vibrio cholera results in cholera and salmonella paratyphi, which results in typhoid.
• Other microbes: Protozoans that inflict dysentery.

What is a Sewer?

A sewer is a network of small and big pipes that form the sewage system. A sewage system characterisation is like a carrier system that transmits sewage from being produced to the point of discarding, i.e., treatment plants.

Wastewater Treatment Plant (WWTP)

Wastewater treatment comprises various chemical, physical, and biological procedures that eliminate chemical, physical, and biological substances that pollute the wastewater. 

The treated water contains a low level of suspended matter and organic material. It is released into the ground, a river, or a sea. Nature further cleans this treated water. Sometimes disinfecting the water with chemicals like ozone and chlorine is required before sending it into the distribution systems.

By-products of wastewater treatment are sludge and biogas. Dried biosolids are used as manure to replenish organic matter and nutrients back to the land. Also, the biogas produced can be used as fuel or to produce electricity. It is generally advised to grow eucalyptus trees alongside the sewage ponds as these trees quickly absorb any excess wastewater and discharge pure water vapours into the air.

Sewage disposal

Alternative arrangements for sewage disposal

• Chemical toilets, septic tanks, composting pits, etc., are the low-cost on-site sanitation process that can be used in the areas where below ground sewage systems and waste removal systems are not accessible.

• Hygienic on-site human waste disposal technology can also be employed in toilets that do not require scavenging. The excreta from the toilet drain goes through into a biogas plant that makes electricity.

• Vermi-processing toilets are another such technology in which human excreta are processed by earthworms. The human excreta is completely converted to vermi-cakes.

Sanitation and Disease:

Contaminated drinking water and poor sanitation are the biggest causes of many diseases.

• Untreated human excreta are a health hazard. It may cause water pollution and soil pollution, resulting in water-borne diseases like dysentery, hepatitis, meningitis, polio, typhoid, and cholera.

• An open-drain scenario is a breeding place for mosquitoes, flies, and organisms that spur various illnesses.

SEWAGE TREATMENT PLANT

A sewage treatment plant is one of the steps to avoid water pollution.

Sewage characterisation is one of the integrated wastewater treatments.

In this treatment, all the sewage characterisation of industrial areas and the company are treated to remove the harmful metal and make it suitable for the environment.

There are two types of systems in sewage plants: 

1. Decentralised system (on-site treatment system)
2. Large centralised system (a connection of an extensive network of pipes)

There are three stages in sewage treatment

1. Primary treatment
2. Secondary treatment – here, organic matter is reduced by aerobic and anaerobic processes.
3. Tertiary treatment – advanced treatment to remove nutrients. 

Many sewage treatment plants are built based on biological aspects by considering the quantitative and qualitative elements. In rural areas, on-site sanitation includes a septic tank, OSS (on-site sewage system), vermifilters, and drain fields. In some countries, even the fourth treatment stage is followed to remove micro pollution. Sanitation is one of the parts of the sewage treatment plant to treat solid waste, human waste, and drainage waste. 

STP- sewage treatment plant for sewage works. WWTP – wastewater treatment for the treatment of sewage characterisation of industrial area.

• The main objective of the sewage treatment plant is to degrade all the biodegradable components, including organic matter, and remove nutrients, pathogens, micropollutants and make them suitable for the environment.
• Even sewage sludge is also treated before its use. It is divided into biosolids and fertilisers.

Conclusion

Many health hazards can occur due to not responsibly managing wastewater. Wastewater management aims to keep the water clean and safe. Through this process, the water can be used for drinking, washing, and commercial purposes. Based on the type of contamination, there are several treatment plants like industrial wastewater treatment plants, agricultural wastewater treatment plants, leachate treatment plants, and sewage treatment plants.