Silos are structures used to efficiently store grain and feed. They provide protected storage that helps prevent moisture damage. Silos are loaded from the top and unloaded from the bottom using conveyors and elevators. Grain arrives by truck or train and is cleaned, weighed, and stored in separate bins within the silo. It can then be removed from the bottom of the silo for transport. India has been increasing silo construction to better store its abundant grain production and reduce losses, adopting models like public-private partnerships.

1. Silos – An Introduction
Silos are a very popular way of storing feed due to their ease of installation, lower expansion cost
and convenient hopper unloading. Silos are installed to store a variety of grains and the sealed roof
and body design helps protect grain/feed from moisture damage.
Grain helps feed the world and silos help producers bring food to your table. These iconic
structures that dot the landscape of many farming areas enable farmers to store grain efficiently.
Silos are simple structures that don't have many high-tech components. However, they still require
careful installation, operation and maintenance.
Silos are atmospheric storage vessels for dry solid materials such as grain, rice and powders. A silo
is typically loaded from the top and material is removed from the bottom using the weight of the
material to push it out. There are multiple methods to fill a silo and one of those methods is the use
of a screw auger to lift material from one location to the top of the silo. An enclosed screw auger
typically is connected to the bottom of a supply truck or rail car. A rotating offset screw turns inside
the auger and transports solid materials down the length of the auger.
How do the Silos Work?
Grain arrives either in wagon through the railway siding provided on one side of the silos or by
road on the other side. The grain is dumped into the rail hoppers or the truck dumps, as the case
may be, and by means of conveyor belts, it is brought to the elevator pit. There the grain is lifted by
the elevator to the height of 175 feet and after initial weight, it passes through the cleaning
machines and then to automatically integrated weighing process, which indicates the quality of
grain that has been fed into each bin. Then the grain drop on to another conveyor belt which
convoys it to various storage bins through Tripper.
For taking out the storage grains, conveyor belts are situated at the bottom of the silos which
takes grain to the elevator pit from where it is lifted to shipping tanks. From here, it is automatically
weighted and shifted in bulk transport or to bags as necessary. There are automatic weighing
machines and stitching machines for shipping out the grain in bags at the rate of 80 to 100 ton per
hour
The silos are also provided with drier tank along the side of the head house is capable of
handling 10 ton of grains per hour and dries the moisture in the grain by heated air produced from
an oil diesel burner. The steel bins are also provided with electric thermocouple temperature
cables and with the help of potential meter. Temperature is recorded monthly, which enable a
watch being kept on their condition of grain.
The grains are also cool down by drawing in air by Aeration FANS when they get unduly heated.
There is a provision of fumigation the grain, when necessary. The silo bins are proof against attack
of insect’s pests or other kinds of infestation.
Power required for running of the elevators and other parts of the plant is provided by three
diesel electric generators, installed specifically for the purpose as a part of the plant. Each
generator has a capacity of 100 K.V.A. Operation of the plant is controlled by a remote control
system and there is a arrangement of inter locking and sequence control in the switch room panel.
Advantages of Grain Silo Elevators

2.  The elevator is capable of handing about 180 ton per hour for both the operations (Storage
and Issue simultaneously).
 Simultaneous storage of different kinds of grain, such as wheat, paddy, gram, bajra, maize in
the different bins at the same time.
 All loading, unloading, weighing etc. are done mechanically.
 There is no access to insects or rodents. Aeration and fumigation can be done when
necessary to preserve the condition of grain. Grain can be stored as long as five years.
 There is provision for thermocouple temperature record system in the plant itself.
 The area of land is required for Silo storage is only about one fifth that of conventional
storage.
 Full proof arrangement in respect of physical check of Food Grain stored silo in bins.
 Consumption of fumigant is very nominal.
 Saving of sacks & Skilled handling laborers at the time of storage.
Indian Scenario
India has been successful in developing agriculture in its fertile northern belt, resulting in an
abundance of grain. Unfortunately, its ability to store it has lagged behind. It is estimated that
globally we lose about 1/3rd of the total food produced. ‘Harvest to Household’ losses in our
country may actually be more than the grain exports from Australia. Current covered storage
capacity with FCI is very low against the requirement. About 12 Mn T Wheat is still lying in open
under Cap Storage waiting to be evacuated. And new crop is about to arrive. Warehousing capacity
has not kept pace with this increase and has resulted in Storage Gap of 35 Mn T.
At present there are about there are four SILOs in India i.e. Calcutta, Madras, Bombay and
Hapur-Ghaziabad. Hence, necessity was felt to augment the storage capacity for food grains in other
parts too.
Accordingly, approximately 200 lakh MT capacity creations were planned with construction of at
various locations in 19 states. As on 30.06.2014, capacity of 153.16 lakh MT has been sanctioned for
construction and 120.30 lakh MT has been completed.
The Government has also approved construction of modern storage facilities in the form of silos of
20 lakh MT capacity within the overall approved capacity for PEG Scheme. Each silo will have
capacity of 25,000 or 50,000 MT. FCI has identified the locations of silos in 10 States. Construction
is being planned in the PPP in both Viability Gap Funding (VGF) and non-VGF modes.
FCI floated a tender for building giant and ultra-modern steel silos in several parts of the country
for modernization of its food grain logistics in 2014.
The public sector undertaking launched e-tender inviting bids under Design, Build, Finance, Own
and Operate (DBFOO) model for a total of 17.50 lakh tonne capacity in 36 locations across nine
states.

3. The DBFOO model envisages the developer to bring in land to construct silos, along with railway
sidings for bulk transportation. The developer will be paid fixed storage charges over the life of the
concession period of 20 years, which is the bid parameter for the project. In addition, the developer
will be paid pre-determined variable and handling charges for movement of food grain.
Recommendations for Silos
 Promote and develop an Efficient,Integrated and Mechanized Bulk Handling, Storage and
Transportation System in the country.
 Offerfull fledged infrastructure status to warehousing with all financial benefits like
cheaper loans, IT and ServiceTax benefits.
 Hub and Spoke System needs to be implemented in India.
 Smaller Silos at Mandi level connected to Mother Silos.
 Mother Silos should have Bulk handling and Rail connectivity.
 Upcountry Silos also should have rail connectivity.
 Changeover fromBox Wagons to Top Loading/ Bottom discharge.
 Wagon would go a long way in improving capacity utilization for Railways.
 Suitable Top loading and Bottom discharge wagon to be made available forhandling Grain.
PrivateSector should be suitably incentivised to create required wagon capacity.
 Silo sites should be notified as Mandis under relevant APMCAct.
 Post Harvest Agriculture Infrastructure couldbe created under PPP model.
 PortInfrastructure should be suitably tweaked to receiveand store in Bulk. This will
facilitate both Import & Exports.