ABSTRACT

This study focused on rice husk generation and utilization among households in Ebonyi State, Nigeria. The specific objectives were to: describe the socio-economic characteristics of households in Ebonyi State; evaluate the perception of respondents on the effects of rice husk generation and utilization on the environment; estimate willingness to pay (WTP) for the removal of rice husk from the environment; determine the socio-economic factors influencing the respondents WTP for the removal of rice husk from the environment; determine the extent of rice husk generation and utilization in the study area; and identify the constraints to rice husk utilization among households in Ebonyi State. Hypothesis: Socio-economic characteristics of households do not significantly determine their willingness to pay for the removal of rice husk from the farmland. Purposive sampling technique was used to select rice production and rice milling areas while random sampling

technique was used to select the respondents. Data were collected by the use of structured questionnaire. Data collected were analysed using mean score, contingency valuation method (CVM)

-   (tobit regression) and F-test. The result of the analysis showed that rice husk is generated in large quantities in the study area while rice husk utilization is still at rudimentary stage. Annual income, years of education, farm size, age and farming experience were positively related to households willingness to pay for the removal of rice husk from the farmland at 5% probability level while household size and distances of homes/farms from rice milling centers (RMCs) were inversely related

to WTP with the pseudo R2 value of 77%. The mean WTP for the removal of rice husk from the environment was N960. The result from mean score used to identify the constraints to rice husk utilization indicated four major constraints to include: lack of awareness; cost of transportation; lack of environmental concern and insufficient information about proper use. Recommendation: Government should commercialize rice husk utilization since the findings showed that it was generated in high quantity in the study area to offer employment to people and at the same time solve the environmental problems created by uncoordinated disposal of rice husk that causes land air and water pollution and conserve the nation’s finite reserve of petroleum.

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CHAPTER ONE

INTRODUCTION

1.1        Background of the Study

Nigeria is West Africa's largest producer of rice, producing currently an average of 3.1 million metric tonnes of paddy rice annually (International Rice Research Institute, 2015). Rice cultivation is widespread within Nigeria extending from the northern to the southern zones with most rice grown in the eastern and middle belt of the country (Fakayode, 2009). The demand for rice has increased at a much faster rate in Nigeria than in other West African countries. For example, during the 1960’s, Nigeria had the lowest per-capita annual consumption of rice in the sub-region, averaging 3kg (Oselebe, Ogah, Odo, & Ogbu, 2013). Per-capita consumption levels grew significantly at 7.3% per annum, averaging 18kg in the 1980’s and 22kg in 1995-1999 (Oselebe et al., 2013). By 2008 it rose to 32kg, with per capita consumption in the urban areas averaging 47kg (Adejumo-Ayibiowu & Bamidele, 2010). Rice production rose gradually over the years with area expansion driven by population growth and urbanization, to surpass other major rice producing countries (Daramola, 2005).

Rice is an important staple food for approximately half of the world population (Slayton & Timmer, 2008). More than 70 countries produce rice though China, India and Indonesia are the major producers (FAOSTAT, 2012). To produce rice, co-product such as rice husk is generated in the rice milling process. This husk accounts for approximately 20-23% of total paddy rice weight (rice crop weight) (IRRI, 2008). Rice husk is one of the most widely available agricultural wastes in many rice producing countries of the world (Kumar, Sangwan, Dhankhar, Mor, & Bidra, 2013). Husks also known as hulls are the hard protecting coverings of grains of rice to protect the seed during the growing season. It is one of the potential biomass sources, but light and bulky. The husk is formed from hard materials. The husk is mostly indigestible to humans. It is removed from rice seed as a by-product during the milling process, and forms 20-23% by weight of the paddy processed. The quantity of rice

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milling by-products generated in Nigeria annually was estimated at about 1,032,993.6 metric tonnes (National agricultural extension and research liaison services & Projects coordinating unit, 2004). Rice husk is used as a value added raw material for different purposes. It possesses various properties that make them suitable for bioethanol production (Sudiyani & Muryanto, 2012). Rice husk biomass is made up of three polymers like cellulose, hemicelluloses and lignin. Rice husk like other lignocellulosic biomass feedstock has been explored as the cheapest feedstock for bio-ethanol production. It is essentially free as waste product from agricultural sector and forest residues. Utilization of these wastes could solve the disposal problem and reduce the cost of waste treatment (Sudiyani & Muryanto, 2012). When rice husk is incinerated, ash is obtained which is called rice husk ash (Megawati, Wahyudi, Sediawan, Hary, Sulistyo & Muslikhin, 2010).

The rice milling process involves cleaning, hulling and post-hulling processes (whitening, polishing and grading), which combined will produce several rice by-products. The percentage of rice by-products is dependent upon several factors, such as the milling rate and variety of rice. An ideal milling process will yield 20-23% husk, 8-12% bran depending on the milling degree and 68-72% milled rice or white rice, depending on the variety (IRRI, 2009). During the milling processes, the husks are removed from the raw grain to reveal whole brown rice, which may then sometimes be milled further to remove the bran layer, resulting in white rice. Rice husk is a common agricultural residue (IRRI, 2009).

The Federal Government of Nigeria has focused on agriculture as a means of diversifying the current crude oil dependent economy and rice is one of the agricultural products that have been earmarked for scaling up. Rice husk is produced in large quantity in the three agricultural zones of Ebonyi State of Nigeria namely; Ebonyi North, Ebonyi Central and Ebonyi South. Rice husk dumps are increasing in alarming proportions in these regions especially in Abakaliki where Abakaliki rice mill industry which is the first milling industry in Ebonyi state is located. For every 1000kgs of paddy milled, about 220kgs (23%) of husk is

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produced, and when this husk is burnt in the boilers, about 55kgs (25%) of rice husk ash (RHA) is generated (Koteswara Pranav & Anusha. 2012). Disposing and evacuating the ri,ce dumps is urgently necessary because of the impending environmental hazards, degradation and pollution it poses to the people and the environs (Koteswara et al., 2012).

The Abakaliki Rice Mill Company (Nigeria) Limited, which is one of the major rice mill companies in Ebonyi State is always a beehive of activities. Currently, the mill boasts of over 5,000 workers, 2,500 rice milling machines, and a production capacity of more than 11,000 metric tonnes per month, which in turn lead to generation of husk that are commensurate to the quantity of paddy (Nwofe, 2013). Rice husk is abundant in Ebonyi State. This has been reported severally in the literature (Nnabude & Mbagwu, 2001; Akanmu & Shridha, 2002; Nwofe, 2013).

The Nigerian Building and Road Research Institute (NBRRI) has laid emphasis on the development of suitable local agro industrial wastes that are abundantly available at little or no cost (Opara, 2011). The waste materials that are available in our environment include rice husk, saw dust, coconut fibre, palm kernel fibre, marble dust, stone dust to mention but a few. Rice husk, for instance, is abundantly produced in many parts of Nigeria such as Abakaliki, Afikpo, Ogoja, Ikepe, Lafiagi, Badeji, Pategi, Sokoto, BirninKebi, Abeokuta, Benin and Delta region. Disposing and evacuating these rice husk dumps is urgently necessary to avert the impending environmental hazards, degradation and pollution it poses to the people and the environs. In attempt to dispose rice husk, most communities, set the rice husk dumps on fire. Unfortunately a small heap of rice husk takes months to get burnt to ashes. Opara (2011), noted that rice husk burns to ashes at the temperature of 800oF. Even when burnt to ashes, it is still an eyesore in the communities especially during the rainy season. Rice husk dump on fire also constitutes serious environmental hazards especially during the harmattan season when the dust devil and other manner of winds blow. It can set nearby buildings on fire. Some people are known to have died by unknowingly running into or stepping into rice

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husk dumps on fire beneath the surface. These husks are dumped indiscriminately around the rice mills and are left to pollute the environment and also cause a nuisance in many ways because they undergo uncontrolled fermentation and putrification, thereby causing hazards to human beings and their environment and equally reducing the aesthetic value of the environment. Rice mill waste can also cause respiratory problems due to its characteristics (Ubwa, Abah, Oshido & Otokp, 2014).

The traditional construction materials such as concrete, bricks, hollow blocks, solid blocks, pavement blocks and tiles are being produced from the existing natural resources. This is damaging the environment due to continuous exploration and depletion of natural resources and need to be substituted with rice husk. Moreover, various toxic substances such as high concentration of carbon monoxide, oxides of sulfur, oxides of nitrogen, and suspended particulate matters are invariably emitted to the atmosphere during the manufacturing process of construction materials (Safiuddin, Mohdzamin, Salam, Islam & Hashim, 2010). The emission of toxic matters contaminates air, water, soil, flora, fauna and aquatic life, and thus influences human health as well as their living standard. Therefore, the issues related to environmental conservation have gained great importance in our society in recent years (Xue, Hou, Zhu, & Zha, 2009). The decision-makers in political, economic, and social sectors are now seriously offering more attention to the environment issues. Consequently, major changes regarding the conservation of resources and recycling of wastes such as rice husk by proper management are taking place in our ways of living and working. Many authorities and investigators are lately working to have the privilege of reusing the wastes like rice husk in environmentally and economically sustainable ways (Aubert, Husson

&   Sarramone, 2006). The utilization of rice husk in construction materials is one of such innovative efforts. The cost of construction materials is increasing day by day because of high demand, scarcity of raw materials, and high price of energy. From the standpoint of energy saving and conservation of natural resources, the use of alternative constituents in

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construction materials is now a global concern. For this reason, the extensive research and development works towards exploring new ingredients such as rice husk are required for producing sustainable and environment friendly construction materials (Aubert et al., 2006).

In the majority of rice producing countries much of the husk produced from the processing of rice is either burnt for heat or dumped as a waste. Evacuation of such heaps of rice husk from the environment has become a big problem due to less commercial interest. Commercial use of rice husk and its ash is a probable alternative solution to disposal problem and potential for greatly altering the situation - turning an environmental liability into a socioeconomic and poverty alleviation asset (Kishamba, 2008). Hence it has become necessary to find avenues of ridding the environment of rice husk waste and to convert such waste into some positive economic uses in Nigeria, especially in Ebonyi State where there is enough quantity of this by-product.

1.2        Statement of the Problem

Abakaliki Agricultural zone of South-East Nigeria is a major rice producing and processing area in Nigeria (Ogbodo, 2010). Large quantities of rice husk are produced annually around the milling centres. The enormous heaps of these rice husks which have piled up in Abakaliki since the 1960 are now the centre of attention. Recently, Ebonyi State Government in collaboration with United Nations Industrial Development Organisation (UNIDO) launched a Global Environmental Facility (GEF)4 Project for Nigeria. The expected output is a Mini grid based on renewable energy using rice husk (biomass) to augment rural electrification. Husk from rice produced since the early 1960s have been preserved in dump sites, towering above the rusty iron sheets of the Abakaliki Rice Mill market and other rice milling centers in the state. This markets has as its backdrop the husk dumpsite, the hills of the husks look like sand hills, giving off different shades of brown, and is estimated to be over 40-metres high as shown in figure 1.1

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Fig.1.1: Rice husk hills in Abakaliki rice mill industry.

Source: Nwofe and Ekpe, 2014.

They are located in the valley-like end of the markets and sitting there not being put to use is really not beneficial in this era of renewable energy. Income can also be increased both directly and indirectly if economically profitable means of utilizing rice husk generated are utilized in industry. The waste has also become problematic and the only way of management has remained burning the wastes. This practice constitutes environmental hazards to the farmers and other inhabitants of the area as the hills continue to dot the landscape, generation of fly ash and dust, contamination of nearby rivers, habitat for pest, rodents, reptiles and mosquitoes and constitution of noise pollution to the host community etc. The disposal of this burnt waste has constituted a problem. There is the need to investigate the use of the rice husk materials for agricultural purposes and other environmental friendly purposes in order to reduce the environmental problems caused by the waste. It has been confirmed by Mbagwu (1991); Obi and Ebo (1995); Nnabude and Mbagwu (1999); and Aniekwe (2000), that returning agronomic wastes to the soil could lead to its structural modifications. Apart from its major role in supplying nutrients, crop residues used as mulch have the potentials to regulate temperature, conserve soil moisture, minimize erosion and result in improved soil productivity (Ogbodo, 2011).

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The problems associated with rice husk disposal can be greatly reduced if the husks can be effectively utilized as animal feed. Some research findings indicated that rice mill wastes contain moderate level of crude protein, and also have low crude fibre and high metabolizable energy (Crampton & Harris, 1969; Singh & Marwaha, 1968). Surin and Tezuka (2006), in their report also stated that biomass is an important energy source harnessed by mankind. It does not add carbon dioxide to the atmosphere as it absorbs the same amount of carbon in growing as it releases when consumed as a fuel. The advantage of biomass is that it can be used as energy source for generating electricity with the same equipment or power plants that are now burning fossil fuel.