The document by Pyrocrat Systems LLP aims to shed light on brief classification of agricultural waste water and its management.

1. Agricultural Waste Water
Management
Suhas Dixit,
CMD,
Pyrocrat Systems LLP,
Navi Mumbai.

2. Agriculture Waste Water
 Controlling the pollution from surface runoff from farms that
may be contaminated by chemicals in fertilizer, pesticides,
animal slurry, crop residues or irrigation water is called as
Agricultural Waste Water Treatment.
 Agricultural Waste Water can be classified into Point Source
and Non-Point Source.

3. Non-point source pollution
 Sediment Runoff: Soil washed off fields is the largest source
of agricultural pollution.
 Excess sediment results in high levels of turbidity in water
bodies
 This can result in inhibition of growth of aquatic plants,
clogging of fish gills and smothering of animal larvae.

4. Reducing Sediment Runoff
Non-point source pollution can be controlled by activities like.
 Contour ploughing
 crop mulching
 crop rotation
 planting perennial crops
 installing riparian buffers

5. Nutrient Runoff
 Nitrogen and phosphorus from fertilizers and manure are key
pollutants found in runoff.
 Can be avoided by proper mapping of fields, obtaining
realistic estimitation of crop yields, conducting soil tests,
analyzing fertilizers and manure.

6. Pesticides
 Pesticides are often used for increasing productivity by
controlling pests.
 The pesticides are hence found even in the surface water.
 Integrated Pest management can be done to promote usage
of biological pesticides over chemical ones.

7. Point Source Pollution
 It is an issue largely associated with farms with livestock and
poultry.
 The waste water is composed of animal waste slurry.
 Animal Waste Slurry can be treated by containment in
lagoons before being sprayed on grasslands.

8. Silage liquor
 Fresh grass or other green crops can be made into a semi-
fermented product using sulphuric or formic acid
called silage which can be stored and used as winter forage
for cattle.
 The process of silage making frequently produces a yellow-
brown strongly smelling liquid which is one of the most
polluting organic substances known.
 Silage liquor that is produced can be used as part of the food
for pigs.

9. Dairy Farming Waste
 Milk causes rapid rapid de-oxygenation of water.
 Dairy farming wastes also consists of wash-down water,
some animal waste and disinfection chemicals.
 Milking parlour wastes are often treated in admixture with
human sewage in a local sewage treatment plant. This
ensures that disinfectants and cleaning agents are sufficiently
diluted and amenable to treatment.

10. Firewater
 Fire is a rare event in farms but Stores of pesticides,
herbicides, fuel oil for farm machinery and fertilizers can all
help promote fire and can all be present in environmentally
lethal quantities in firewater from fire fighting at farms.
 Containment of substantial quantities of firewater shall be
pre-planned along with its subsequent recovery and disposal
by specialist disposal companies as the concentration of
contaminants in firewater makes them unsuitable for the
wastewater to be used for any other application.

11. Agricultural Waste Water Treatment
 Screening : At this stage, large objects like diapers, sanitary
items, bottle caps, plastics, broken bottles, etc. are separated
from the waste.
 Primary Treatment : This part of the process is used to
remove organic material from the water. The waste is then
placed in large settlement tanks for the sludge to sink to the
bottom.
 Secondary Treatment – Once the sludge has been
removed, the water is placed in rectangular tanks called
aeration lanes.
 Final Treatment – The water is moved into settlement tanks.
More sludge is formed at the bottom of the tanks due to the
bacteria breakdown. It is scraped and collected for
treatment. Water is then released into the river.

12. Physical Treatment
 Sedimentation, flotation, adsorption, barriers such as bar
racks, screens, deep bed filters, and membranes are used in
physical agricultural wastewater treatment.
 The use of this method removes waste by using naturally
occurring forces including gravity, electrical attraction and van
der Waal forces in addition to physical barriers.

13. Chemical Treatment
Chemicals are used to accelerate disinfection using various
techniques like.
 Chemical Coagulation – Most common method for removing
dissolved metals from wastewater solution containing toxic
metals.
 Chemical Precipitation – Involves destabilizing wastewater
particles so that they aggregate during chemical flocculation.
 Chemical Oxidation – An oxidizing agent is added during
chemical oxidation. Electrons move from the oxidant to the
pollutants in wastewater.

14. Chemical Treatment (contd.)
 Advanced Oxidation – Helps remove any organic
compounds that are created as a result of chemical oxidation.
 Ion Exchange – Ion exchange is a process that can be used
to soften water. Positive sodium ions in the form of sodium
chloride, salt or brine are added to the water.
 Chemical Neutralization and Stabilization – Similar to
chemical oxidation, sludge is treated with a large amount of
oxidant. This slows down the rate of biological growth in the
sludge. This also works as a deodorizing agent.

15. Biological Treatment
 Biological wastewater treatment uses organisms like bacteria,
nematodes, and other small organisms to break down organic
substances in wastewater.

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