Abstract
Coir industry is one of the important traditional cottage industries widely spread over South India. The case of Coco products, a small-scale industry located in Gubbi, Tumkur District, Karnataka, India, which is in the Coir fibre production, is considered. Coconut husk is the basic raw material of the industry. Tumkur district happens to be one of the prominent coconut growing areas in the state. The speciality of this region is that edible copra is obtained from coconut. The Coir fibre extracted from the husk is used in local bedding, mat and matting, rubberized Coir mattress, yarn and rope making etc. The byproduct of this industry is Coir pith. 

In the process of extraction of Coir fibre from husk, generally about 1/3rd of it is obtained as fibre and 2/3rd of it is obtained as Coir pith. Coir pith with a range of interesting properties finds various applications. Coir pith has a high lignin (31%) and cellulose (27 %) content and a carbon-nitrogen (C/N) ratio of 104: 1. (Shekar, 1999). Coir pith also has a very high water holding capacity of 5 to 6 times its weight. It should be noted that Coir pith is very stable because of the presence of high percentage of lignin. Hence Coir pith left to itself takes decades to decompose. Studies by various institutions have resulted in methods to speed up the process of decomposition (lignin reduction) by fungal/microbial culture. The decomposing or composting of Coir pith is done near agriculture fields, in heaps generally by the Pleurotus sojarcaju species an edible mushroom, which takes around 35-45 days. Composted Coir pith is used along with organic supplements in crop fields in horticulture and floriculture. It is also used as a rooting and growing medium for certain ornamental flowering plants. Decomposed Coir pith is also used as hydroponics systems for growing roses and vegetables under controlled conditions. The Coir pith in sterilized condition finds use in mushroom cultivation and floriculture. The Coir pith also finds application as an alternative for 'Peat Moss' the extraction of which has been banned in most of the European country. It also finds application as a mulching material for grapevine. 

Coir pith has a calorific value of 3975 k cal/kg, close to 4200 k cal/kg of coal. It can also be used as fuel briquettes with the ash content almost 1/10th of coal. A proper methodology or technology for briquetting Coir pith is yet to be developed for manufacturing a commercially viable product. 

Here in our case, on an average a husk weighs about 300 g, 80-85 g is obtained as fibre and around 200 g is obtained as Coir pith. Further on an average 5000 husks are defibred per day, which yields 1000 kg (1 ton) of Coir pith per day while around 5-6 tons is composted or decomposed in batches for every 35-45 days depending upon the requirement. As mentioned earlier, out of the rest of Coir pith, some quantity is sterilized and dispatched to be used chiefly in floriculture. Thus, the Coir pith, which was once a waste and had a disposal problem, has a commercial value. Infact today it is even being exported to other countries by some other units and has both internal and external market. Finally, we have arrived at cleaner and eco-friendly as well as profitable method of disposing the byproduct - Coir pith. 

INTRODUCTION 

Coir industry is one of the important traditional cottage industries in India. It is a labour intensive and export oriented industry. It provides employment to over 50,000 workers all round the year 80 % of the workers engages in the industry is women. Coir industry in India is over one and half century old. The first factory in India was setup during the pre-independence period in Alleppey by a European called James Dhara of Irish origin. 

The basic raw material of the industry is the coconut husk, from which the Coir fibre is extracted. The husk is the out fibrous material of the coconut. The biological name of coconut plant is Cocus nucifera. Here we are presenting the case of Coco Products, located in Gubbi, Tumkur district of Karnataka State, India. Coconut plantations are one of the chief crops of farmers all over Karnataka. Hence there is a lot of availability of the above said raw material, coconut husk. Before the existence of the Coir industry, the coconut husk was dried and used as fuel. This is even practiced at some places. With the amount of raw material available there are 196 registered Coir industries in Karnataka State. In Karnataka alone the coconut production is in 290, 000 ha area and the production of coconuts in 1493 million nuts during the year 1996-1997. 

Earlier, coconut husks were considered to be a throwaway material, it found a commercial value for extraction of Coir fibre. The Coir fibre is extracted from a process called retting. 

Retting involves soaking the husks in water for a certain period until the fibre becomes loose and soft. The soaking is done in cement tanks in this case. During the retting process, the husk becomes soft and a number of substances like carbohydrate glycosides, tannin and nitrogen compounds are brought in solution. The carbohydrates and nitrogen compounds are acted upon a great variety of anaerobic organisms, which produce various organic acids and gas. When the fermentation progresses, the temperature of the husk increases, water becoming turbid due to gas formation and frothing and pectin in the middle lamella of the husks slowly dissolves. Subsequently, the rate of fermentation shows down and the water becomes clear without the evolution of gases and the consequent frothing and, at this stage the husks are ready for removal. The time required for retting is influenced by various factors such as the stage of maturity of coconuts, the weather and the nature of weather and the nature of weather (P.K. Thampan, 1987). 

The retted husks are beaten in machines called Defibring machine or with wooden mallets as in the traditional case, and hence the Coir fibre is extracted. Broadly, there are two major types of Coir fibre. They are white fibre and brown fibre. 

The Coir fibre extracted from the husk by crushing in defibring machines in our case is used in local bedding, mat and matting, rubberised Coir mattress and rope making etc. For the rubberised Coir mattress curled Coir is used.

In the process of extraction of Coir fibre from husk, generally one third of it is obtained as fibre and two thirds of it is obtained as Coir pith. Coir pith was earlier considered as 'waste'. Wastes are often materials for which beneficial uses are not known is not economical, so that some sort of innovation is needed to find ways of using them. (R. Iranpour et al, 1999). 
 
 

Coir pith with a range of interesting properties finds various applications. Coir pith has a high lignin (31 %) and cellulose (27 %) content and carbon-nitrogen ratio of 104:1(C.A. Shekar, 1999). Coir pith also has to vary high water holding capacity of 5 to 6 times its weight. It should be noted that Coir pith is a very stable product because of the presence of high percentage of lignin. Hence Coir pith left to itself, takes decades to decompose. The Coir industry under study completes 25 years of Coir fibre production this year. The characteristics of Coir pith, that were generated as waste, 20-25 years back, were found to be on par with the decomposed Coir pith, unlike the raw Coir pith. Hence the Coir pith left to itself takes a span of 20 years to decompose itself. Further the Coir pith will decompose in the soil only very slowly, as its pentosan lignin ratio is less than 0.5, which is the minimum, required for the slow decomposition of organic matter in the soil. (P.K. Thampan, 1987). The nutritive value of Coir pith is given in the following table (Before composting). 
 

The Coir pith is excellent surface mulch in all kinds of soil. It absorbs over eight times its weight of water and parts with it slowly. It has been found that by incorporation of 2 percent weight of Coir pith with sandy soil, the water holding capacity of the latter is increased by 40 percent. 

Coir Pith Composting

Since Coir pith takes decades to decompose and in the early 1990's it posed environmental hazard and disposal problem. Various research institutions were successful in methods to speed up the process of decomposition by fungal or microbial culture. Coir pith can be successfully composted either in the area of the industrial yard or in the agricultural fields itself. The Coir pith composting is done by using mushroom cultures or fungal cultures. The mushroom popularly used belongs to the Pleurotus species. They are commercially sold in spawn bottles. Normally one spawn bottle weighs around 300g. Further to compost about 1 ton of Coir pith 1.5 kg of spawn and 5 kg of urea are needed. The composting technique is as described below.  

Mark an area of 5 m length and 3 m width in selected place which is preferably under shade. Spread uniformly on the marked area, one hundred kilogram (approximately) of Coir pith. Inoculate with one bottle of the spawn of Pleurotus species by applying uniformly over the well spread Coir pith. Cover uniformly with another hundred kilogram of Coir pith over the Pleurotus species inoculated layer of Coir pith. Apply one kilogram of urea uniformly over the layer of Coir pith. Cover the applied urea with the next layer of one hundred kilogram of Coir pith. Repeat the process of sandwiching the Pleurotus species and urea alternatively with hundred kilogram layers of Coir pith to a height of one meter. Sprinkle water if the moisture content of Coir pith is below 200 %. Normally the heaps of Coir pith at the industry have 500 percent moisture. Therefore if the Coir pith is found over dried sprinkling of water is required. Keep the heap for thirty days of decomposition and sprinkle water if necessary periodically. At the end of thirty days, the Coir pith may be found turned into dark or black mass of compost, having a reduced C : N ratio of 24:1 and with increased availability of macro nutrients and micro nutrients. 
 
 

By addition of urea to Pleurotus species the nutrient level increased as given. 
 

Coir pith compost could also be effectively marketed. Marketable Compost should be 
(i) of consistent size, 
(ii) Free of glass, plastic and metals and 
(iii) free of objectionable odours (Tchobanaglous et al, 1993). 

This composted Coir pith confirms to all these conditions. Further by the addition of certain nutrients like urea, super phosphate and murate of potash, it could make a basic nutrient complex - the manure mixture of 6:6:10. If this is done successfully this can commercially marketed as 'Enriched Bio-manure'.
 

Composted Coir pith is used along with organic supplements in crop fields in horticulture and floriculture. It is also used as a rooting and growing medium for certain ornamental flowering plants. Decomposed Coir pith is also used as hydroponic systems for growing roses and vegetables under controlled conditions. 

The raw Coir pith is also sieved for separating it from small Coir fibres of 5 to 10 centimeters in length. This results in obtaining fine Coir pith. This is further sterilized to avoid the phytotoxic pathogens. The moisture content of this will be 40 %. The pH and electron conductivity of the sieved-sterilized Coir pith is 6.5 and 1.1-m mho respectively. This sieved-sterilized Coir pith is used as soil conditions in floriculture.

Coir pith has a calorific value of 3975 kcal/kg, close to 4200 k cal/kg of coal. It can also be used as fuel briquettes with the ash content almost 1/10th of coal. There have been developed hydraulically operated briquetting machine to produce solid and strong round fuel briquette (by Dry process), which can server very well as an alternate economic fuel in place of coal in industries. 

Coir pith with a range of interesting properties finds applications in nurseries, floriculture etc. The use of Coir pith in eucalyptus has been dealt here. The composting of Coir pith is done at the agriculture field as in this case. The composted Coir pith is applied uniformly on the mother bed of eucalyptus. Once the plants are transferred from mother need in plastic covers of 1/2 litre volume. It is mixed with Coir pith compost and mud in the ratio of 1:2 by volume. After about 1 and half month, the plants are transferred to other places and are ready for plantations are called 'Plantlets'. 
 
 
 

Finally today, we have various applications of the Coir pith, which was once a waste and caused disposal problem. The Coir pith being chiefly composted and with certain additives, can become a good supplement for fertilizers. 

Further, some more research has to be undertakes on the wastewater that is obtained after retting. Though there has been no physical ill effects visible, it is recommended that its use for agriculture or irrigation fields should be explored. 

REFERENCES

P.K. Thampan.1987. Handbook on Coconut Palm. Oxford & IBH.pages 272-273. 

R. Iranpour, Moghddam, O., Kharraghani. S., Longley, J., Jelee, J., Schroeden, E. 1990. "The Future of Environmental Engineering; Resources and Economics", Water 21, Sept-Oct 1999, 12-14. 

Jachim AWR. 1973. The Manurial Value and Decomposability of Coir Fibre Dust. Trop. Agri., 272-73. 

Tchobanoglous G., Theisen, H. and Vigil, S, 1993. Integrated Solid Management, McGraw Hill, New York. 

Shekar, C.A. 1999. Application of Coir pith in Internal and Export Market. National Seminar on Coir, Coir Products and Coir Pith. 
 

Acknowledgement

The authors gratefully acknowledge the encouragement given by Prof. T.P. Halappa Gowda, Head, Department of Environmental Engineering, Sri Jayachamarajendra College of Engineering, Mysore, Karnataka, India. The authors are also very grateful to Dr. M. Mahadevaswamy, Department of Environmental Engineering, Sri Jayachamarajendra College of Engineering, Mysore, for his constant guidance. The authors are also thankful to everyone in the Department of Environmental Engineering, Sri Jayachamarajendra College of Engineering, Mysore. Further the authors are also thankful to Mr. M.K. Srinath, Datta Krishna Orchards, Gubbi, Tumkur District, Karnataka, India. The authors are also thankful to everybody who helped during the preparation of the manuscript.