sekam

Sekam, or rice husk, is the protective outer layer of rice grain that remains after milling paddy rice. It is one of the most common agricultural byproducts in rice-producing regions, typically collected from rice mills and stored for various uses. Sekam is lightweight and durable, with a high silica content that contributes to its abrasive texture and versatility in industrial and agricultural applications.

Chemically, sekam is rich in silica (silicon dioxide) and also contains cellulose and lignin. It offers little nutritional value for humans but can be an important resource when properly processed or mixed with other materials. In its ash form, rice husk ash (RHA) has a high silica content and is used as a supplementary material in cement and concrete production, as well as in filtration and adsorption applications.

The main uses of sekam include energy, agriculture, and construction. It is burned as a biomass fuel in boilers and rural stoves, providing a source of heat in many communities. The resulting rice husk ash is used as a pozzolanic additive to improve cement properties and as a component in various filtration media. In horticulture, sekam is employed as a growing medium or soil amendment due to its drainage and aeration benefits, often mixed with other substrates to retain moisture. It is also used as animal bedding and, in some cases, processed as a feed additive.

Environmental and economic considerations are linked to sekam management. As a plentiful agricultural residue, improper disposal or open burning can contribute to air pollution, whereas recycling into soil amendments, filtration media, or cement additives supports waste reduction and value recovery in rice regions.