Bentonite-enhanced Rice Husks As Landfill Covers: An Essay On Impervious Barriers.

Write a report on te topic on Bentonite Added Rice Husk As Impervious Barriers Of Landfill Covers.

Globally, rice producing countries generate rice husks as one of the most available agriculture wastes. Annually it is estimated that 600 million tons of rice paddies are produced from that averagely 20% is rice husks. Which gives a total of approximately 120 million tons annually. If rice husks are poorly managed they will cause a  great threat to the environment which can easily cause a lot of damage to the land and the surrounding Areas (Engineers, 2016, p. 235). Therefore, the commercial use of rice husks and its ash is the alternate solution to the problem that the rice producing countries face.

Rice husks is an agricultural byproduct or residue of rice milling industry. Different rice samples have different chemical composition this is due to the varying climatic conditions on which the rice was grown. The current conditions of the world greatly demand for the use of durable materials which are also very strong. Landfill cover refers to a layer of compressed earth or soil that is laid on top on deposition of an operational landfill site. The covers assist in preventing the interactions between the air and the wastes. This greatly reduces odors and offers a stable base upon which machinery and vehicles may operate (Shulz, 2016, p. 184).

The rice husks have been accepted as green supplementary material that has many applications ranging from small scale to large scale. It can be used as a cover in landfill sites and water proofing. In other situations, in other cases the rice husks ashes are used as admixtures to improve the chemical resistance of concrete.

Due to the large amounts of rice husks that are produce in various countries it has been a great challenge on how to dispose them. This calls for studies in order to come up with ways on how the husks can be used commercially. (Rakshit, 2014, p. 338).With the current trends in the construction industry and the advances in the technology industry  there is need for durable and sustainable materials such as the rice husks.

This report focuses on the use of bentonite added rice husk as impervious barriers of landfill covers. From the studies that have been carried out by many scholars regarding to this subject. The sustainability of rice husks ash mainly depends on the chemical composition of the ash, predominantly the silica content available.

The main aim of this study was to find out how to utilize bentonite added rice husk as impervious barriers of landfill covers. With that many other objectives were set to aid in achieving the main aim of the study. The specific objectives in this study included: -

1. To carry out a detailed literature survey regarding to bentonite added rice husk as impervious barriers of landfill covers, in order to get a deep understanding of this topic.
2. To find out what are the properties of rice husks ashes
3. To determine the application of rice husks ashes in various industries such as construction
4. To understand the various burning process of rice husks and the quality of ashes obtained from them.

Applications of Rice Husks Ashes in the Construction Industry

This study is carefully crafted to find out how bentonite added rice husk as impervious barriers of can be used as landfill covers. The findings of this study will be of great importance to the conservation of the environment since the disposal of rice husks has been a great challenge in many countries globally considering that rice is a staple food in many countries.

The study will mainly focus on how the bentonite added husks can be used as landfill covers. With that the research will be tied strictly to the topic of study. Any other information not related to the topic of research will not be investigated. Various sources both primary and secondary sources that contain information relevant to this topic will be reviewed.

(Crini, 2013, p. 563)conducted some experiments to study the impact of mixing rice husks ash together with bentonite in an effort to upgrade it as a construction material. The outcome of that study enabled him to conclude that stress strain behavior of the unconfined compressive strength indicated that failure strain and stress increased by 50% and 106% respectively, the moment the rice husks ash content was increased from 0% to 25% and when the rice husks content was increased from 0% to 12%.

According to (Rodgers, 2016, p. 149) carried out the research on the behavior of the clay soil, which was stabilized with the rice husks ash that was mixed with the soil to study the enhancement of the weak subgrade in terms of the strength and compaction characteristics. The silica produced from the rice husks ash was found to be successful as a pozzolainc material in the soil stabilization.

(DeWinter, 2013, p. 382)carried out a research on the impacts of the rice husks ashes on the engineering properties of black cotton soil. The findings of the research concluded that with the increase in the rice husks percentage the optimum moisture content in the soil increased from 18.25 to 22 percent. The maximum dry density also decreased from 1.68 to 1.51gm/cm3. There was a great increase in the values of California bearing ratio and the unconfined comprehensive strength.

The rice husks have been accepted as green supplementary material that has many applications ranging from small scale to large scale. It can be used as a cover in landfill sites and water proofing. In other situations, it is also used as an admixture to make the concrete resistance against the chemical penetration (Youngquist, 2016, p. 43).

Different Types of Burning Methods for Rice Husks

The rice husks ash as wide applications in the construction industry such as;

• Insulation
• Green concrete
• Industrial factory flooring
• Swimming pools concreting the foundations
• Rehabilitation and water proofing

As initially mentioned the quality of the rice husks greatly depends on the type of burning process which they undergo. Various types of burning methods are usually carried out such as,

1. Open Field Burning method

This technique of open burning of the rice husks usually produces ash of poor quality. These usually produces highly crystalline form structure which has lower rates of reactivity.

1. Fluidized -Bed Furnace Burning method

In this technique the burning of the rice husks is controlled. The heat that is produced during the combustion process is used to generate electricity. The operations that are controlled are carried out by controlling the time and temperature. The combustion is carried out at temperatures between 500 and 700 degrees Celsius. The process is carried out for a longer period to ensure that carbon is completely removed or the same is achieved by increasing the temperature from 700 to 800 degrees Celsius for a period of 1 minute (Engineers, 2016, p. 670).

The husk ashes produced from this method contains 80% to 95 % silicon dioxide, 3-18% of unburned carbon and 1-2% of K₂O. The ash produced by this method has a higher cellular structure.

• Industrial Furnace

This technique is mainly used to facilitate economic and environmental reason. The ashes produced by this method have amorphous silica and cellular structure. The ashes also obtained from this method are highly pozzolanic.

The sample soil that will be used for this study will be collected from a local dumping site and the rice husks will be collected from the local rice mills. The rice husks will be burnt on an open field in order to convert them to rice husks ash. The Bentonite that was used will be sodium bentonite. Standard procedures will be followed while various laboratory experiments were carried out. 

Data for this study will be collected by use of various methods. Both primary and secondary sources will be used. For the secondary all the books, journal and other publications that contain information related to the topic of research will be reviewed while for the primary sources various practical sessions will be organized where by experiments will be done.

The role of the researcher in this study will be to collect data regarding to the topic of research, at the same time it will his or her responsibility to come up with the most appropriate techniques and approach of collecting data and also to organize the research according to the timeframe.

Methodology

From the experiments that were carried out the hydraulic conductivity of soil when tested alone was high. This clearly indicates that soil was highly permeable which cannot be used as covers for land fill as there will penetration of water and odour from the wastes to the surrounding air. The addition of bentonite and rice husks ashes to the soil reduced the permeability of the soil by reducing the amount of water passing through it. That was attributed to the facts that the fine particles of bentonite filled the voids in the soil and therefore reducing the amount of water passing. Also from the experiments carried out it can be concluded that additional of 20% bentonite and 20% rice husks ashes greatly reduced the permeability of soil and therefor making it better for use as landfill covers. The addition of bentonite added rice husks ashes greatly contributes to the improvement of the soil strength (Centre, 2016, p. 665). At the same time the addition of bentonite added rice husks to the soil increase the plastic limit of the soil and at the same time reduces the shrinkage limit of soil, this makes that soil to be ideal for landfill covers.  

Conclusion

In conclusion, the challenge of how to dispose the rice husks that are produced in plenty in rice producing countries has called for research to come up with ways on how the rice husks can be used commercially. This, study shows ways in which the bentonite added husks can be used as land fill covers have been discussed.

From the literature review that has been conducted it can be concluded that the addition of bentonite added rice husks ashes greatly contributes to the improvement of the soil strength. The rice husks ashes have the ability to stabilize the soil and therefore the addition of it together with bentonite improves the strength in soil. Bentonite being a clay mineral greatly contributes to the transformation of the shear strength of soil.

References

Centre, I. N. S. D., 2016. Indian Science Abstracts. 4th ed. Chicago: Indian National Scientific Documentation Centre.

Crini, G., 2013. Sorption Processes and Pollution: Conventional and Non-conventional Sorbents for Pollutant Removal from Wastewaters. 1st ed. Chicago: Presses Univ. Franche-Comté.

DeWinter, F., 2013. mankind's future source of energy: proceedings of the International Solar Energy Society Congress,. 5th ed. Sydney: Pergamon Press.

Engineers, N. B. o. C. &., 2016. Manufacture of Value Added Products from Rice Husk (Hull) and Rice Husk Ash (RHA)(2nd Revised Edition): How to Manufacture Rice Husk based Products, Forming Products from Rice Husk, Rice Husk Ash Fuel & Powder Value Added Products, Rice Husk based Product. 3rd ed. London: Niir Project Consultancy Services.

Rakshit, A., 2014. Nutrient Use Efficiency: from Basics to Advances. 4th ed. Londn: Springer.

Rodgers, B., 2016. Rubber Compounding: Chemistry and Applications. 3rd ed. Texas: CRC Press.

Shulz, W. W., 2016. Science and Technology for Disposal of Radioactive Tank Wastes. 3rd ed. Chicago: Springer Science & Business Media.

Youngquist, J., 2016. Literature review on use of nonwood plant fibers for building materials and panels. 3rd ed. Paris: U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory,.