TREATMENT OF EFFLUENT GENERATED FROM RAW RUBBER SHEET PRODUCTION BY BIOMETHANATION A LABORATORY STUDY

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1 ABSTRACT MGIRED Journal Volume 2(1) : ISSN TREATMENT OF EFFLUENT GENERATED FROM RAW RUBBER SHEET PRODUCTION BY BIOMETHANATION A LABORATORY STUDY Natural rubber is high in demand globally and is used in almost every application. In Costal area, particularly Dakshina Kannada region, farming is one of e main occupations in which rubber, areca nut, coconut, paddy, etc., are grown. Rubber plantations are common and rubber sheets are manufactured at e site. Wastewater generated from e rubber sheet manufacturing is acidic and high in BOD, COD, solids, sugars and proteins. Wastewater generated from e rubber sheet manufacture process is directly disposed on land. This practice is causing odour nuisances, breeding of flies and mosquitoes and also can lead to water and soil pollution. Since ese units are small and in clusters at e place of e rubber plantations, some low cost economical way of wastewater treatment is needed, which will also help e farmers. In is study an attempt is made to analyse e characteristics of rubber sheet manufacturing wastewater and to treat it by biomeanation process at lab scale. Biomeanation meod helps in treatment of waste wi energy recovery from e waste. Various trials of biomeanation wi seeding materials were conducted. Results of lab scale biomeanation showed significant reduction in COD and BOD wi e generation of biogas. Key words: Rubber Wastewater, Rubber Sheet Production, Biomeanation, Anaerobic Digestion. INTRODUCTION Ashwin Koilparambil and Shambavi Kama M Department of Civil Engineering, Manipal Institute of Technology, Manipal, Karnataka , India. ashwinkoil@gmail.com, kamamiyar@yahoo.com Natural rubber industry products have a large demand globally for eir various uses in different applications. Rubber is used to manufacture products in every field, from automobile parts, medical devices, plumbing, electrical, stationary, etc. India is ranked ird in e world producers of natural rubber, Vijayaraghavan [1]. Agriculture is e main 1

2 Biomeanation of Effluent from Raw Rubber Sheet production occupation in Dakshina Kannada region of Karnataka. Rubber, Areca nut, Paddy, Coconut, etc., are commonly grown in is region of which e rubber industry is e most polluting. Rubber industry pollutes rough e wastewater generated during manufacture and also air emission depending on e drying process adopted. Rubber industry is vast as it consists of farms, estates and factories, hence farms and estates do not come under e jurisdiction of e Pollution Control Boards. The farms and estates come under e agriculture sector and pollution control norms cannot be enforced upon e farmers. In Karnataka, e rubber cultivation area is 28,830 hectares and produces 20,000 metric tonnes of rubber annually. The Rubber Board has identified areas in Karnataka which is suitable for rubber cultivation and is providing subsidies for new planting and re-planting, Rubber Board [2]. Conversions of coconut plantations into rubber plantations have been reported, and hence an increase in rubber production Ashwini [3]. These statistics show at e rubber production in Karnataka will increase during e next few years. Hence an economic treatment meod needs to be adopted to ensure pollution control at e farms along wi benefits of eir investment. Rubber Industry Natural Rubber latex is a milky white liquid obtained from e rubber tree (Hevea brasiliensis). Rubber tree grows in tropical climates wi moderate rainfall and has an economic lifespan of about 25 years, Ukan [4]. It starts yielding latex after it is around 7 years old and each tree produces about 600ml of latex per tapping depending on e climatic conditions. Tapping of a tree is done on alternate days so as to reduce e strain on e tree and ensure longer economic lifespan of e tree. Latex is tapped by fracturing e bark of e tree, after which e latex flows out into containers below e fractured area. Liquid latex contains around 60% of dry rubber, Shantipanusopon [5] and it varies wi e climate, i.e. e water content in e latex increases during e monsoon season. Latex is used to produce five main products, namely Ribbed Smoked Sheets (RSS), Air Dried Sheets (ADS), Block Rubber, Crepe Rubber and Concentrated Latex. These products are furer used to produce oer rubber products for various applications such as tyres, gloves, insulations, tubes, etc. In Dakshina Kannada region, Ribbed Smoked Sheet and Air Dried Sheets are e commonly produced of e five types, and are similar except for e meod adopted for drying. These are produced from small scale farms to large scale plantations. 2

3 Original Research Article Koilparambil & Kama Rubber Sheet Manufacturing Process In e production of Ribbed Smoked Sheets and Air Dried Sheets, latex from e plantation is carried back to e rolling house for processing. In certain cases where e plantation is located far away from e rolling house, ammonia is added to e latex to prevent early coagulation. Early coagulation of rubber particles before e processing stage leads to e production of low grade sheets and hence an economic loss. If ammonia is added to prevent early coagulation, en higher amounts of acid are required during e coagulation stage. At e rolling house e latex is mixed wi water in a ratio of 2:1 to improve its consistency, and formic acid (5ml for 2 litres of latex) which helps in coagulation. A mixture of 2 litres rubber latex, 1 litre water and 5 ml formic acid is poured into trays and left for around 6 hours to coagulate and form a ick mass. After it sets, e mass is rolled to form sheets. Two sets of rollers are used, one flat roller to reduce e ickness and remove excess water, and e oer ribbed roller to rib e sheets which also removes excess water. Sheets are en sent for drying, which takes few days depending on e drying meod adopted and climatic conditions. Rubber Wastewater Wastewater generation in e production of Ribbed Smoked Sheets and Air Dried Sheets is during e rolling process. Wastewater generated is acidic, wi high BOD, COD, dissolved solids, sugar, protein lipids, etc, Nguyen [6], and hence are highly polluting and cause odour nuisances if not treated before discharge. Regular practice in small scale farms is to discharge e wastewater into e ground where e sheets are being rolled. This practice has e potential to pollute ground water, surface water and soil, it also provides a breeding ground for mosquitoes and flies. The rate of generation of wastewater from rubber sheet manufacture varies wi climate, availability of water at e rolling house, number of sheets produced, and also from person to person who is employed to tap rubber and manufacture e sheets. Variation wi climate is due to e water content in e raw latex produced by e trees, i.e. during winter and monsoons e water content in e raw rubber latex is high when compared to during summer. Water content in e latex is e highest during e monsoon. Variation wi person to person occurs in e quantity of water added to e raw latex during processing of e sheets and also e amount of water used during e washing process. Number of sheets produced varies due to climate and also e frequency of e tapping process, hence e number of sheets produced can cause a variation in e generation rate of wastewater and also e wash water. 3

4 Biomeanation of Effluent from Raw Rubber Sheet production Biomeanation Anaerobic digestion or biomeanation is a natural biological process when bacteria break down organic matter in environments wi little or no oxygen, Molino [7]. Among several renewable technologies, biomeanation technology is a commercially proven technology and is widely used for treating biomass, Krishania [8] converting it to stable compost and to produce bio fuels in e form of meane. In is study, e process of biomeanation is adopted to treat e effluent generated by e manufacture of natural rubber sheets along wi agriculture wastes. The C/N ratio for efficient digestion of organic matter should be in e range of 25-30, Kafle [9]. The process was attempted in Vietnam but failed due to e formation of H S gas, which inhibited e 2 meanogenic activity, Nguyen [6]. H S gas was formed due to e high concentration 2 of sulphates from sulphuric acid being used as a coagulant in e rubber manufacturing process, Nguyen [6]. In is study, e coagulant used in rubber sheet manufacture is formic acid and hence does not add sulphates to e wastewater. MATERIALS AND METHODOLOGY Rubber wastewater generation rate was studied at e rubber plantation for a period of 2 weeks. Wastewater was measured manually and an average value was calculated on 2 maximum generation days. General characteristics such as BOD, COD, ph, Total Solids, Dissolved Solids, Ammonical Nitrogen, Nitrates and Sulphates for ree different samples of e rubber wastewater were tested in e laboratory using standard procedures from IS Sample 1 was a concentrated sample obtained directly from e rolling process, sample 2 was obtained from e washing process and sample 3 was a mixed sample obtained from e end of e manufacture process. Biomeanation Trials Biomeanation trials were conducted in air tight glass and plastic bottles in which provisions were made for gas collection. Bottles were sealed air tight, insulated and covered using black paper to prevent e entry of light. Various trials of biomeanation were conducted on sample 1 wi different seeding materials. Stirring of e samples were done manually twice a day. Agriculture waste was collected from e rubber plantation, cow dung and sewage treatment plant sludge were collected at Manipal, and poultry manure was collected from Century Chicken Farms located at Perampally. All materials used in e biomeanation process were available at e rubber plantations. Treatment efficiency was measured in terms of COD and BOD removal. 4

5 Original Research Article Koilparambil & Kama Trial 1: Trial 1 was conducted in a 2 liter glass bottle in which 1500 ml of e rubber wastewater sample, 30 gm of e agriculture waste and 300 ml of cow dung slurry were filled. The generated gas was collected by water displacement meod and flared occasionally to check for e presence of meane. 4 ml of sewage treatment plant sludge was added on e 7 day. The process was stopped after 13 days. Trial 2: Trial 2 was conducted in a 500 ml glass bottle in which 400 ml of rubber wastewater sample wi ph adjusted from 5.06 to 6.10 was mixed wi 50 ml cow dung slurry and filled into e bottle. The generated gas was collected by water displacement meod and flared occasionally to check for e presence of meane. The process was stopped after 10 days. Trial 3: Trial 3 was conducted in a 500 ml glass bottle in which 300 ml rubber wastewater sample, 20 gm agriculture waste, 30 ml cow dung slurry and 20 ml sewage treatment plant sludge were filled. After 9 days kitchen waste (banana peel and potato peel) was added to e bottle. The generated gas was collected by water displacement meod and flared occasionally to check for e presence of meane. The process was stopped after e 17 day. Trial 4: Trial 4 was conducted in a 2 liter glass bottle in which 1000 ml rubber wastewater sample, 66 gm agriculture waste, 66 gm poultry manure, 100 ml cow dung slurry and 60 ml sewage treatment plant sludge were filled. The generated gas was collected by water displacement meod and flared occasionally to check for e presence of meane. After e 6 day, e gas was collected in a rubber tube so as to collect lager amounts of gas and for a longer period. On e same day approximately 100 gm banana peel waste was shredded and added to e process. On e 38 day, e gas was flared, COD of e wastewater sample was tested to determine e removal efficiency and e process was stopped. Trial 5: Trial 5 was similar to trial 4, and hence only e gas was flared after 40 days. 5

6 Biomeanation of Effluent from Raw Rubber Sheet production Trial 6: Trial 6 was conducted in 2 bottles, in which 950 ml rubber wastewater sample and 50 ml meanogenic sludge was filled into each. The seeding i.e. meanogenic sludge, was reduced to 5% in is trial. Bo bottles were connected to rubber tubes for gas collection. On e 45 day, e gas was flared and e wastewater sample was tested for COD and BOD to determine e removal efficiency and e biomeanation process was stopped. The nitrates content of e sample was also tested. Trial 7: Trial 7 was conducted similar to trial 6 except for e seeding material used. In is trial 50 ml of cow dung slurry was used as e seeding material. Trial 8: Trial 8 was conducted in an 1800 ml plastic bottle in which 900 ml rubber wastewater sample and 100 ml of meanogenic sludge for seeding were filled. The meanogenic sludge used in is trial was prepared in e lab by complete anaerobic digestion of cow dung slurry for 122 days, which had stopped producing biogas. The gas was collected by water displacement meod and flared regularly up to e 16 day to test e presence of st meane. On e 31 day e gas was flared again and e process was stopped. The COD of e biomeanated sample was tested to determine e removal efficiency. RESULTS AND DISCUSSION The average wastewater generation was found to be m /sheet and m /day. The general characteristics of e rubber wastewater are shown in Table I, which shows high streng in all 3 samples in terms of BOD, COD and solids. C/N ratio of e wastewater was found to be and at of e agriculture waste was found to be 1,135. Trial 1, 2 and 3 were stopped due to failure in e biomeanation apparatus and meanogenesis temperature not being attained. Trial 4 showed significant reductions in COD wi e generation of biogas, which burned wi a blue flame. Trials 6 and 7 showed significant reduction in BOD and COD but did not yield sufficient meane content for e gas to burn. In trial 8, e gas generated up to e 16 day did not contain sufficient meane to burn, but e gas generated furer up to e 38 day burned wi a blue flame. Completely digested meanogenic sludge seeding used in is trial shows at e gas generated was from e rubber processing effluent alone. Figure-I shows e BOD and COD removal efficiency in trials 4, 6, 7 and 8. 6

7 Original Research Article Koilparambil & Kama Hence from e results obtained, it shows at rubber wastewater can be treated by biomeanation and wi e addition of agriculture wastes to e process can produce useful biogas. Since e wastewater generation rate is low and most farmers own biogas plants at eir farms, e rubber wastewater could also be added to e biogas plant to reduce construction costs of a separate digester. Furer studies need to be conducted on C/N mixing ratios of e wastes and increasing e HRT in e process. Table 1: General Characteristics Sl. No. Parameter Sample 1 Sample 2 Sample 3 1 BOD (mg/l) 10,656 1,728 8,064 2 COD (mg/l) 20,800 2,560 9,920 3 ph Total Solids (mg/l) 27,840 5,000 17,400 5 Dissolved Solids (mg/l) 25,920 4,400 13,560 6 Sulphates (mg/l) Nitrates (mg/l) Figure 1: Experimental trials wi varying BOD and COD removal percentage 7

8 Biomeanation of Effluent from Raw Rubber Sheet production REFERENCES [1] Krishnan Vijayaraghavan (2008). Electrolytic treatment of Standard Malaysian Rubber process wastewater. Journal of Hazardous Materials. 150, [2] Rubber Board indentifies 1 lakh hectare land in State, [3] Shannikodi Ashwini (2013). Contemporary Agriculture Issues from Dakshina Kannada: A Field View, International Research Journal of Social Sciences, 2(1), [4] Ukun M. S., Soedjanaatmadja & Toto Subroto (1995). The effluent of natural rubber factories is enriched in e antifungal protein hevein. Journal of Bioresource Technology, 53, [5] Sirinapa Santipanusopon & Sa-Ad Riyajan (2009). Effect of field natural rubber latex wi different ammonia contents and storage period on physical properties of latex concentrate, stability of skim latex and dipped film. Journal of Physics Procedia, 2, [6] Nguyen (2012). Situation of wastewater treatment of natural rubber latex processing in e Soueastern region, Vietnam. Journal of Vietnamese Environment, 2, [7] Molino A. (2013). Biomeane production by anaerobic digestion of organic waste. Journal of Fuel, 103, [8] Meena Krishania (2013). Analysis of different techniques used for improvement of biomeanation process: A review. Journal of Fuel, 106, 1 9. [9] Gopi Krishna Kale, Sang Hun Kim (2013). Anaerobic treatment of apple waste wi swine manure for biogas production: Batch and continuous operation. Journal of Applied Energy, 103,