This document discusses the effects of domestic wastewater treatment on soil properties. It explains that domestic wastewater contains nutrients, pathogens, and other pollutants. Treatment processes like sedimentation, screening, and biological and chemical treatments are used to clean the wastewater. These treatment processes can affect soil properties by forming sludge layers, decreasing fertility, increasing pH and salinity, and nitrifying the soil. Proper wastewater treatment and management is needed to reuse wastewater and prevent soil pollution.
2. WASTE WATER
• The term waste water is referred to the water which is discarded after
primary use, or which is worthless, defective and of no use.
• TYPES OF WASTE WATER-
-DOMESTIC WASTE WATER
-INDUSTRIAL WASTE WATER
-AGRICULTURAL WASTE WATER
-SURFACE DRAINAGE WATER
3. DOMESTIC WASTE WATER
• Domestic waste water carries used water from houses
and apartments; it is also called sanitary sewage. Also
the water that is used for performing household chores
or domestic purposes is known as domestic waste water.
4. WHAT IS WASTE WATER ?
Wastewater is 99.9% water.
The other 0.1% is what is cause for concern. That 0.1% includes:
Nutrients: Phosphorous and Nitrogen
Fats, oils, grease: cooking oils, body lotions
Pathogens: disease-causing bacteria and viruses
BOD-biochemical oxygen demand. BOD is a measure of oxygen
needed by aerobic bacteria to break down organic matter. A
higher BOD means there is more organic matter that needs to be
broken down.
Other solids
6. WASTE WATER TREATMENT
• Wastewater treatment is a process in which the solids in
wastewater are partially removed and partially changed by
decomposition from complex highly putrescible organic solids to
mineral or relatively stable organic solids.
• There are numerous processes that can be used to clean up
wastewaters depending on the type and extent of contamination.
• Wastewater can be treated in wastewater treatment plants which
include physical, chemical and biological treatment processes.
7. TREATMENT PROCESSES
PHYSICAL PROCESSES
In physical processes we do not treat the water with any chemicals.
Water with solid impurities can be treated with this method
• - Sedimentation
• - Screening.
• - Aeration.
• - Filtration.
• - Flotation and skimming.
• - De-gassification.
• - Equalization
11. In the septic tank, the solids settle to the bottom and a scum
forms on the top, similar to the process that occurs in settling
tanks in municipal wastewater treatment plants.
Once separated, the water flows out to the drain field, and
screens and compartments keep the sludge and scum inside the
tank, where bacteria begin to partially digest the sludge.
When the partially treated wastewater enters the drainfield, it
begins to infiltrate the soil and percolate downwards.
So long as the soil is appropriate, the microbes in the soil digest
the pollutants, removing the bacteria, viruses and excess
nutrients by the time the water reaches the groundwater
source.
12. When the soil is not suitable, or there are nearby water sources, an
alternative system may be used, so that water sources do not become
contaminated.
The alternative system may use sand, peat, or plastic instead of soil.
Constructed wetlands, lagoons, aerators, or disinfection devices are also
effective in treating the wastewater
It is estimated that around half of all rural wells are contaminated, many
from septic tanks. The United States Centers for Disease Control and
Prevention suggests that wells should be at least 15 meters from septic tanks,
but this distance also varies according to the type of soil.
13. EFFECTS ON SOIL
Domestic waste water treatment effects soil as the
processes are made in the underground area, due to which
the properties of soil are affected. These processes affect
the soil properties in following ways
Formation of sludge on the upper layer of the soil.
Decrease in fertility of soil.
Increase in ph. range of the soil which can be called as
acidification.
Nitrification of soil
Increase in salinity of soil
15. CONCLUSION
If you are using a septic system, it is important to maintain it
properly, as failure to do so could result in the leakage of
pollutants into the soil or water sources.
Appropriate wastewater treatment and water management
practices will have to be followed to allow the reuse of
untreated Domestic wastewater.
Hence proper measures should be motorized to ensure that
these treatment processes do not result in soil pollution.
