Filtration Systems in An Irrigation Perspective

Filtration is a process whereby impurities present in water are separated from the liquid. There must be a filter in every irrigation system. A filter provides simple insurance to prevent debris from entering your irrigation system, regardless of how pure your water is. Water with even microscopic particles can clog drip emitters. Here we are discussing the various details regarding the filtration systems in irrigation.

What are the different types of water sources available for Irrigation?

Water sources: 

Surface sources, including ponds, lakes, streams, rivers, storage reservoirs, and oceans, are now not typically used for water supplies.

Underground sources or subsurface sources:

An infiltration well, a spring, and wells and tube wells.

Factors depending on the selection of filtration system

1. Source of water supply.

2. Irrigation system types.

3. Planned flow (Filtration volume).

4. Impurities in the water/quality of water.

Biological, chemical, and physical contaminants are all present.

5. Impurity concentration.

6. The objective and desired level of filtering required.

7. Backwash operation: manual or automatic.

8. Cost efficiency.

What are the different types of Physical Impurities?

• Sand, clay, and silt particles.

• Solid Substances.

• Particles in suspension.

• Waste 

• Garbage; 

• Leaves and Branches

•  Turbidity

• Taste & Smell; Colour.

• The temperature.

• Ice.

• Grass, foliage, twigs, roots, flowers, and fruits.

• Fish, insects

What are the different kinds of chemical impurities?

• pH.

• EC. (Electrical conductivity)

• TDS. Total Dissolved Solids.

• Total Hardness.

• Calcium.

• Manganese

• Carbonates.

• Chlorides.

• Sulphates.

• Sodium.

• Iron.

• Potassium

• SAR-Sodium Absorption ratio

What are the different types of biological impurities?

•  Algae 

• Organic impurities (Decomposed organic) 

• Bones/skin of dead insects/fish. 

• Bacteria. 

• Protozoa. 

• ‘e’ Coli.

How to take a water sample?

Take a sample from the middle of the water source in a 1-litre empty water bottle. And send it to the lab within 24 to 48 hrs.

Different kinds of Filtration unit and their type of flow and purposes.

 

Filtration Unit	Types of Flow	Purpose
Hydro cyclone filter/ Sand Separator.	Vortex Flow	To remove silt, and heavier solid particles.
Screen Filter / Mesh filter	Two-dimensional flow	To remove fine particles.
Disc Filter	hree-dimensional flow	To remove algae, clay, particles.
Sand / Media filter	Scattered / Three-dimensional flow	To remove algae, suspended particles, clay & all physical impurities.

Hydrocylone Filter

With the help of a straightforward but clever design that consists of a conical casing with a tangential inlet, suspended particles with densities greater than water are flung outward by centrifugal forces where they meet the casing perimeter and sink to the bottom where either a drain valve to enable flushing or a small chamber to increase the filter capacity is located. It is placed in areas with sand-containing water, typically in well water. The Automat has high-grade engineering plastic hydrocyclones with connection sizes of 2, 2.5, and 3 inches and enhanced UV resistance for long life. According to system requirements and line flow rates, this can be used.

Screen Filter

Constructed of plastic and supported by a frame with holes. The screen allows water to travel through while also having the ability to catch particles. Such filters can't effectively filter out significant quantities of pollutants and are typically not advised for removing organic materials like algae. The Automat has 80, 120, and 150 mesh size screen elements available, as well as 2", 2.5", 3", and 4" connection size screen filters made of high-grade engineering plastic with additional UV protection for long life. According to system requirements and line flow rates, this can be used.

Disc Filter

When we stack and compress polymer discs, which have a unique grooves on both sides, we create a three-dimensional structure with several screens that allow water flowing from the outside of the disc cylinder to be filtered deeply. Disc filters can be used to clear modest loads of organic waste because of their distinctive structure.

Sand Filter

Suspended debris, as well as floating and sinkable particles, are removed using sand filtration. The wastewater flows vertically through a fine bed of sand and/or gravel. Particles are eliminated through physical encapsulation or absorption. The filter has to be rinsed if there is an excessive amount of pressure loss.

Various water sources and their proposed filtration systems.

The type of filtration system changes for different types of water sources. Here are some examples;

Bore well             - Screen filter or Sand separator + Screen filter

Canal                     - Sand separator + Screen filter

Open well            - Sand filter + Screen filter

Dam / Lake         - Hydroclone + Sand filter + Screen filter

 

Emitter plugging can happen while utilising micro-irrigation for physical, biological, or chemical reasons. Preventing issues from arising before they do is crucial, as prevention is better than cure. The most effective prevention technique comprises a strategy for maintenance, water treatment, and filtration. The proper design and functioning of the micro-irrigation system depend on water analysis.