WASTE ABATEMENT AND MANAGEMENT IN NATURAL RUBBER PROCESSING SECTOR ED 78.20 Industrial Waste Abatement and Management Prepared by Group 3: HOANG NGOC TUONG VAN DANG THI THUY DUONG NGUYEN THI MAI THANH THACH HUYNH THI THU TRANG IMASTINI DINURIAH SUBARNA SHARMIN HUYNH MINH KHAI TRAN NGUYEN QUANG HUY 104946 104953 104945 104960 101481 104766 104964 104963 ASIAN INSTITUTE OF TECHNOLOGY SCHOOL OF ENVIRONMENT, RESOURCES AND DEVELOPMENT April 2007 INTRODUCTION Natural rubber (NR) processing sector is an industry which produces raw materials used for the manufacture of rubber industrial products (conveyor belts, rubber rollers, etc.), automotive products (fan belts, radiator hoses, etc.), latex products (rubber gloves, toys hygienic products, etc.) and many kinds of adhesives (see Figure 1.) The major users of natural rubber are tire and footwear industries NR MANUFACTURING NR PROCESSING industrial products (conveyor belts, rubber rollers, etc.), automotive products (fan belts, radiator hoses, etc.), Rubber Sheet LATEX Crepe Rubber Crumb Rubber rubber gloves, toys hygienic products Latex Concentrate Skim Latex Figure Flow diagram of typical Natural Rubber (NR) processing and manufacturing The raw material used for natural rubber processing is latex mainly tapped from rubber tree (Hevea brasiliensis) Historically, natural rubber has been used since pre-columbian period by ancient people in Mexico, Peru, and the Amazon Basin but its processing industries were firstly developed in Brazil in 1870 However, due to the lack of labor sources and limited land for rubber tree plantations in Brazil, the industries move to Asian countries where land and labor sources are abundant Therefore, it is reasonable that nowadays Asia is the main source of natural rubber in the world, which account for around 94% of output in 2005 and the three largest natural rubber producing countries i.e Indonesia, Malaysia and Thailand account for around 72% of all natural rubber production (http://en.wikipedia.org/wiki/Natural rubber, 2007) Natural rubber factories are always located around the plantation area, and they could be categorized from small scale to large scale industries depending upon the size of rubber tree plantation As the demand of rubber products is increasing time to time, the existence and development of natural rubber processing sectors become significantly important Data from International Rubber Study Group in http://www.lgm.gov.my/nrstat/nrstatframe.html showed that global natural rubber production increased from 6,440 metric tons in 1996 to 8,821 metric tons in 2005, whereas its consumption increased from 6,110 metric tons in 1996 to 9,000 metric tons in 2005 (see Annex 1, Table 1.) It is estimated that world net exports in 2010 are projected to grow by 1.3 percent annually to reach 5.5 million tons, 15 percent above the average of 1998-2000, with the bulk of the increase from Indonesia, Vietnam and some smaller Asian countries (www.fao.org., 2007) Raw material products from natural rubber processing sector provide huge benefits to human beings as they are exploited to manufacture many kinds of important rubber goods However, environmental damages generated from this sector could become big issues Natural rubber processing sector consumes large volumes of water and energy and uses large amount of chemicals as well as other utilities It also discharges massive amounts of wastes and effluents The most common environmental issues are wastewater containing chemicals and smell, hazardous waste, noise, and thermal emission In order to reduce the damage in the environment, waste abatement and management in natural rubber processing sector should be handled properly This paper is presented to discuss in detail about natural rubber processing sector in terms of its processing operations, major environmental issues generated from the sector and its sources as well as its characteristics In addition, waste treatment practices and identification of CP potential in this sector are conferred One case study referring to Xuan Lap natural rubber processing in Vietnam is also discussed NATURAL RUBBER PRODUCTION PROCESSESS The raw material used for the production of natural rubber is “white milky fluid” called latex taken from the latex vessels of rubber trees, which can be categorized as field latex, scrap, soil lump, and bowl lump Chemically, latex consists of rubber, resins, proteins, ash, sugar, and water Verhaar (1973) mentioned that rubber content in the latex comes from the trees is approximately 30 to 40% Latex, which is a kind of biotic liquids, will be deteriorated if it is not preserved by ammonia or sodium sulfite which is called anticoagulant Anticoagulants prevent latex from pre-coagulation The kind of anticoagulant used is depended upon the production process Sodium sulfite is preferred if crepe or sheet rubbers are to be made, but ammonia is more suitable for latex concentrate In summary, the product of natural rubber can be broadly classified under two categories i.e dry and liquid rubber Dry rubber refers to the grades, which are marketed in the dry form such as rubber sheet, crepe rubber, and crumb rubber, whereas liquid rubber refers to the latex concentrate production in which the field latex is separated into latex concentrate containing about 60% dry rubber and skim latex with 4-6% of dry content Skim latex is produced as a byproduct during the preparation of latex concentrate It has a dry rubber content of only to 7% and its dirt content is very low Coagulation of skim latex can be either spontaneously or by acid treatment It is important that the ammonia content is kept as low as possible Further processing is the same as for smoked sheet The processing of miscellaneous latex also exists in some factories (see Annex 6, Figure 6.) Referring to the whole steps in natural rubber processing, it is obvious that both dry and wet processes are involved Size reduction, digestion, washing, and drying are unit operations involved in these processing activities The step of washing consumes large amount of water, so that wastewater generated from these processing operations mainly comes from this step Brief descriptions of processing of each type of natural rubber are presented below 2.1 Processing of rubber sheet Rubber sheet could be categorized as Air Dried Sheet (ADS) and Ribbed Smoked Sheet (RSS) The main difference of ADS and RSS is on the method used for drying the sheet, in which ADS exploits air, whereas RSS uses smoke provided in a smokehouse with the temperature up to 60°C The original type of smokehouses has been replaced by so-called “Subur” smokehouses The principle of the design of these houses is to eliminate as much as possible manhandling of sheets The smoking chambers are on ground level, so that trolleys can be loaded with sheets in the factory and then transported by rail into the smoke chambers The smoking process in the “Subur” smokehouses is basically a continuous process Rubber sheet processing is started from latex collection in the field It is then diluted and screened before the addition of formic acid for coagulation process The wet sheet is sheeted off to a thickness of about mm and finally passes an embossed two roll mill The sheets are dried whether by air or in a smokehouse for about one week at temperatures The specific smell of the smoked sheets is caused by the wood and other organic materials such as coconut shells used to produce the smoke The sheets produced are finally classified and packaged The flow diagram of rubber sheet processing is presented in the Annex 2, Figure 2.2 Processing of Crepe rubber Crepe rubber is made from latex field coagulum In the production of crepe rubber from latex, the raw material is prevented from coagulation by adding ammonia After transported to the factory, latex is filtered through a screen to remove coagulated rubber, particles, or leaves It is then transferred to mixing tank with stirring blade after determine dry rubber content (DRC), latex is diluted with water to reduce DRC to 20 – 22% In the production of crepe rubber, there are three important steps Diluted latex from mixing tank is transferred to stationary coagulation troughs through movable throughs Acetic or formic acid solution (2%) is normally used to neutralize ammonia added in the field for coagulation prevention and to reduce pH to 5.0 – 5.2, near the isoelectric point of 4.3 The second step is primary and secondary milling After coagulation, water is added to coagulation troughs to float up the coagulum In water, coagulum is easy to move to milling machine After primary milling, slabs of coagulum is passed through pair of roller of which the final one is grooved so as imprint on each the rib to increase the surface area for drying Each roller is equipped with water sprayers to wash away non rubber particles Then coagulum is cut into small, then it is dried by hot air and pressed The flow diagram of crepe rubber processing is presented in the Annex 3., Figure 2.3 Processing of crumb rubber This type of natural rubber product is relatively new, which in trade market it is known as “technical specification rubber” (Setyamidjaja, 1993) There are some benefits of crumb rubber processing i.e the process is faster, the product is more clean and uniform, and the appearance of product is more interesting Raw materials used for making crumb rubber can be field latex or low quality lump The steps included in crepe rubber processing using field latex are latex coagulation, milling, drying, bale pressing, and packing Coagulation process uses 1% formic acid plus 0.36% melase Sodium bisulfate is usually added to the coagulation mixture to get brighter end-product If the raw material used is lump, the step will be started by soaking and/or washing the lump, and then followed by hammer milling, crepe formation, milling, drying, bale pressing, and packing The flow diagram of crumb rubber processing is presented in the Annex 4., Figure 2.4 Processing of latex concentrate Latex colleted from the field is pre-treated such as screen, wash and ammonia addition before processing After processing, the field latex is centrifuged Because the disperse phase (rubber) and the continuous phase (water mainly) differ in density, the concentrated latex (60%) rubber is separate and is collected from the center of centrifuge bowl, whereas skim, about 5% rubber, is taken from the outer edge of centrifuge bowl The concentrate latex is bulked, ammoniated and then stored The skim latex is deammoniated, coagulated with acid, creped and dried The flow diagram of rubber sheet processing is presented in the Annex 5., Figure ENVIRONMENTAL ISSUES PROCESSING SECTOR OF NATURAL RUBBER Despite the numerous benefits that are rendered to the modernization of this world by natural rubber, the consequence of natural rubber processing has yet provide a serious problem due to its highly polluted effluents The rapid growth of this industry generates large quantities of effluents coming from its processing operations which is really a big problem because of its wastewater contains high biological oxygen demand and ammonia Without proper treatment, discharge of wastewater from rubber processing industry to the environment may cause serious and long lasting consequences 3.1 Major environmental problems 3.3.1 High concentration of BOD, COD, & SS Wastewater discharged from latex rubber processing usually contains high level of BOD, COD and SS (see Table 2) These characteristics vary from country to country due to difference in raw latex and applied technique in the process The main source of the pollutants is the coagulation serum, field latex coagulation, and skim latex coagulation These compounds are readily biodegradable and this will result in high oxygen consumption upon discharge of wastewater in receiving surface water Table Typical characteristics of wastewater from rubber processing Type of pH BOD COD SS processing 5.05 4,080 8,080 Ribbed smoked sheet rubber Latex 8.95 34,900 58,752 14,142 concentrate 5.30 3,645 5,873 1,962 - Creaming - Centrifuging 6.8 137 464 303 Crumb Crepe 5.7 2,260 4,667 391 - Pale latex 6.9 137 469 386 - Estate Brown Note: All Parameters are expressed in mg/I, except pH Source: India Central Pollution Control Board, 2001 TDS Sulfide 4,120 ND 28,307 13,597 - 804 - 2,303 513 44 - 3.3.2 Acidic effluent It is noted by Pandey et al (1990) that the effluent from latex rubber processing industries is basically acidic in nature Different extents of acid usage in the different factories attribute to pH variation of different effluent Due to the use of acid in latex coagulation, the effluent discharged from latex rubber factories is acidic and re-dissolves the rubber protein The effluent comprises mainly of carbonaceous organic materials, nitrogen and sulfate The quantity of acid used for coagulation of the latex, specifically in skim latex after centrifugation operation, is generally found to be higher than the actual requirement 3.3.3 High concentration of ammonia and nitrogen compounds The high concentration of ammonia presents in the latex concentrate effluent posed another serious threat to the environment Most of the concentrated latex factories in the South of Thailand discharge treated wastewater that contains high level of nitrogen & ammonia to a nearby river or canals leading to a water pollution problem If high level of ammonia is discharged to water bodies, it could lead to death of some aquatic organisms living in the water Land treatment system has been conducted to treat and utilize nitrogen in treated wastewater from the concentrated latex factory 3.3.4 High level of sulfate The effluent from latex concentrate factories contains high level of sulfate which originated from sulfuric acid used in the coagulation of skim latex The high level of sulfate in this process can cause problem in the biological anaerobic treatment system as high levels of H2S will be liberated to the environment and generates malodor problem The free H2S also inhibits the digestion process, which gives lower organic removal efficiency (Yeoh et al., 1993) 3.3.5 High level of odor The odor causing compound such as hydrogen sulfide, ammonia, amines, can be produced by many of wastewater treatment process Most odor of organic nature arises from the anaerobic decomposition of compounds containing nitrogen and sulfur (Dague, 1972; Henry, 1980) The odor is detectable even at extremely low concentrations and makes water unpalatable for several hundred miles downstream from the rubber plants The problems presents varies considerably depending on the plant site, the raw material used, and the number of intermediary product Most rubber factories in Songkhla province have been forced to use activated sludge process or aerated lagoon to prevent the bad smell from the anaerobic condition Table Gaseous concentration emission from latex processing No NH3 (mg/m3) Process unit H2S (mg/m3) Reception tank 0.23 – 8.53 0.022 – 0.03 Coarse chopping 0.21 – 1.67 0.017 – 0.021 Cutting/Rolling 0,23 – 0.67 0.019 – 1.27 Granulating 0.18 – 0.53 0.018 – 0.024 Centrifuging 2.56 - 4.42 0.008 – 0.012 Drying 0.15 – 0.36 0.01 - 0.021 Packaging 0.19 – 0.25 0.005 - 0.016 Source: Environmental Monitoring Report, 2004 – Dau Giay and Long Thanh latex rubber processing factories, Vietnam 3.3.6 Favorite condition for pathogenic bacteria A large population of bacteria also presents in the effluent discharged from the factories The type of bacteria found in rubber effluent are coliform, Streptococci and E.Coli Most of constituents of the effluent can act as substrate for the growth of these microorganisms (Baskaran, 1980) 3.2 Pollution Norms Table Typical Wastewater/ Effluent Discharged per ton of Product Product Effluent (m3) Skim latex 25 Latex concentrate 18 Miscellaneous latex 35 Total flow rate 106 m3/year Source: Vietnam Rubber Company, 2004 3.3 Wastewater pollution load (kg/ton) Table Wastewater pollution load Parameter Latex Skim concentrate latex Miscellaneous Crumb latex rubber Pale latex Estate brown latex Flow - 18 25 35 45 45 43 COD 32 - 140 180 75 21 210 20 BOD 20 - 74 105 45 101 TS 37 – 75 45 30 36 104 22 TN – 11 1 N-NH3 3-9 - 1 Source: Synthetic data from Vietnam and India Latex rubber Industry WASTE TREATMENT PRACTICES The waste treatment practices may change accordingly to the characteristics of effluent discharges and allowable limitations Waste treatment practices include practices for wastewater treatment, air pollution control and solid management Of all environmental issues generated from this industry, wastewater is the major problem with a wide range of effects on human health and environmental health Air pollution and solid management are not major problems hence in this paper we mainly focus on wastewater treatment practices 4.1 Wastewater treatment practices Wastewater collected from rubber processing factory contains a variety of substances as well as the commercially important constituent, in this case rubber hydrocarbon It contains proteins, minerals, non-rubber hydrocarbons and carbohydrates This wastewater has high concentration of ammonia, BOD5, COD, Nitrate, Phosphorus as well as total solids Moreover, the wastewater from latex concentrate and skim crepe industry contains sulfate which comes from sulfuric acid in the skimming process and in some processes produce rather high content of zinc and cadmium Wastewater treatment practices can be mentioned as pollution abatement Pollution abatement involves (a) in-plant control of waste and (b) end-process treatment of wastewater Some in-plant control measures can be introduced to enable reduction in consumption of water, generation of pollutants and to increase the efficiency of the end-of-process wastewater treatment 4.1.1 In-plant control measures In the crepe and crumb rubber units, in which field coagulum is processed, high required water quantity is generally used for soaking and also the soaking time allowed is not adequate If the raw scrap rubber is properly soaked and primary dirt removal is done by scrap-washer, the quantity of water consumed in milling can be reduced In the crumb units, wastewater from final milling can be collected separately from the effluent of the other milling section and can be used either for soaking the scrap rubber or for the first milling process This is comparatively clean and the amount of reduction can be up to 25% of the total water consumption In centrifuge machine bowl, washing is done at the interval of 3-4 hours to remove the sludge About 0.5% rubber is lost during this washing step To reduce loss, washing step can be done at two stages The first washing which is more concentrated may be segregated and collected in a separate tank and coagulated for recovery of the rubber lost during washing This will result in reduction of pollution load in the effluent The possibility of diverting this waste stream into the skim coagulation tank can also be considered The quantity of acid used for coagulation of the latex, especially skim latex kit after centrifugation stage is generally found to be higher than the actual requirement The time needed in coagulation tank is also less The incomplete coagulation results in the loss of rubber particles into the effluent along with the skim serum The excess acid not only causes acidic effluent but also re-dissolves the rubber protein and causes delay in coagulation Hence, it is suggested that proper acid concentration applied and sufficient coagulation time should be provided to obtain more or less clear liquid after complete coagulation The skim latex if de-ammoniated before coagulation, acid requirement can be reduced and the ammonia concentration in effluent may also be reduced In the latex process units the segregated first washing of the coagulum may be diverted to the skim coagulum tank where after skim coagulum recovery, the effluent may join the other wastewater streams 4.1.2 End of process treatment Basically wastewater treatment can be divided into pretreatment, primary treatment, secondary treatment, and tertiary treatment Pretreatment The rubber trap used for arresting suspended matters should have holding capacity of at least 12 hours with proper baffles to induce continuous up and down flow pattern If designed properly, this can reduce suspended solids by 40 to 60% The equalization tank should have at least one day detention time It is preferred to have two equalization tanks, each of them with one day detention time Primary treatment For a latex processing unit, effluent from the equalization tank to be sent for neutralization and chemical treatment by alum and iron salt (about 200 mg/l) Combined wastewater of latex process units also needs neutralization by using of lime and settling of suspended solids by using of coagulants The settler/clarifier should have adequate detention time for removal of suspended solids The sludge may be taken to sludge drying beds for dewatering The dewatering of sludge produced by primary clarifier is normally carried out on belt or vacuum filters which raises the sludge consistency from 20 to 40% Secondary treatment Following the primary treatment, the effluent should be subjected to the biological treatment If sufficient land area is not available, then the effluent after primary settling may be subjected to an extended aeration activated sludge type biological treatment process Before going for biological treatment, it must be ensured that: (a) All the in-plant control measures are adopted, (b) Primary treatment e.g rubber trap equalization neutralization and clarification steps are incorporated The above measures will reduce substantial quantity of pollutants particularly BOD and suspended solids The primary treated effluent can be treated in a secondary/biological treatment unit It is envisaged to render secondary treatment by adoption of extended aeration activated sludge process The biological treated effluents should be settled in a secondary settling tank If there is no constraint of land, the biological treatment could be anaerobic followed by aerobic pond system with the proper dimensions, holding capacity and adequate detention time (10 to 15 days) for anaerobic pond followed by to 10 days for aerobic ponding system The type of soil and proximity to the wastewater and ground water table condition should be taken into consideration before going for these treatment systems Protective lining is recommended to eliminate any risk In place of the anaerobic-aerobic system, an oxidation ditch of detention time of 2-3 days can also be considered as an alternative for treating the effluents of the crumb rubber unit Depending on the real conditions of countries and specific processes, some units of wastewater treatment are modified and adjusted to have better efficiency For example, most of the latex concentrate factories in the South of Thailand discharge treated wastewater that contains high level of nitrogen to a nearby river or canals leading to a water pollution problem Land treatment system is used to treat and utilize nitrogen in treated wastewater from the concentrated latex factory The land treatment system resulted high removal efficiency for nitrogen (Rungruang, 1998) In recent years, many studies were carried out to treat wastewater from this industry by biological methods such as ASP (activated sludge process) and use of oxygenic phototrophic bacteria for treating latex rubber sheet wastewater (Thongnuekhang and Puetpaiboon, 2004) These studies aim at improving the efficient treatment of wastewater from this industry and contribute to partially reduce the emission of toxic gases into the environment Tertiary treatment The remaining components after primary and secondary treatment are residual SS, residual BOD, odor and hydrocarbon Tertiary treatment designed to remove these components are generally carbon adsorption, massive lime treatment and foam separation, mainly for treatment of Residual Refractory Organics The flow diagram of treatment system adopted presently given in Annex 8., Figure 4.2 Air pollution control In production process, a mixture of poisonous gases is generated from coagulation of rubber and latex It should be controlled and reduced by activated carbon treatment Chimney gases should be controlled technically, otherwise it might affect the growth of agricultural plants in the fields Besides, foul smell due to wastewater drainage is a problem and it is difficult to control It can be reduced by applying in-plant measures or cleaner production such as reducing the amount of wastewater generated from the process and separating wastewater from the latex immediately when discharged Most rubber factories in Songkhla province, Thailand have been forced to use activated sludge process or aerated lagoon to prevent the bad smell from the anaerobic condition Air pollution control is related to wastewater treatment methods Hence, air pollution control can be obtained by controlling and treating wastewater from production process IDENTIFICATION OF CP POTENTIAL IN NATURAL LATEX RUBBER PROCESSING A closed look reveals that rubber industry consumes large volumes of water, uses a lot of chemicals and other utilities and discharges enormous amounts of wastes and effluents The few cleaner production assessments and implementation programs carried out in many countries has shown tremendous benefits Some of them are lesser usage of chemicals, efficiency in energy and utilities including water, improvement in productivity and profitability, lesser loads and volumes of effluent discharged to the neighborhood, better image and relationship with employees internally and with the neighborhood externally Rubber Tapping and Transportation Usage of traditional coconut shell as the cup for latex collection gives a large cup lump increasing the scrap crepe This should be replaced by a plastic bowl and the traditional galvanized iron bucket is replaced by plastic buckets The addition of chemicals to the field latex is still a problem and training of tapers and other personnel seems to be the main option available The transportation of the field latex by mild steel bowlers adds rust to latex A coating of epoxy is very effective to eliminate rust contamination of latex Coagulation A simple partitioning of the coagulation tank using wooden planks will be very effective instead of cutting the coagulum to size by a knife as in tradition This saves labor involved and the blocks are of uniform size, which produces uniform edged laces at milling Skim Coagulation In centrifugation unit, the scrum water contains about 1% rubber which is usually coagulated using sulfuric acid The addition of ammonia in the field as well as in the factory prior to centrifugation results in high usage of acid for skimming and causes many problems in final treatment of effluent To get the most effective latex formulation and chemical dosing at field and in the factory through controlled trials is the most appropriate solution to the problem which is complicated and time consuming The long-term benefits of this solution are very attractive Before skim coagulation, the de-ammoniation of effluent helps to reduce usage of sulfuric acid In all latex concentrate factories the scrum water from latex, centrifuge wash water and bowler wash water is discharged as one stream The segregation of these streams can help to reduce final treatment cost and possibility of recycling of the wash water with a little treatment for selected uses Energy Consumption The uniform edged laces reduced the milling needs and blankets and bundles formed took lesser time In the dryer tower the internal partitioning and systematic passing of hot air from chamber to chamber improved the drying efficiency Scrum Water The serum water has many nutrients and other substances, which can be of high commercial value Trials are being conducted to use serum water as a liquid fertilizer 10 Step 4: Accounting for wastewater Average Flows, strengths and Pollution Loads of Strong Liquors Wastewater Centrifugation Flow m3/d BOD pH mg/l COD kg/d mg/l 158 6.25 5,565 897 9,450 SS Total N kg/d mg/l kg/d mg/l kg/d 1,493 2,050 324 250 40 Combine wastewater flows, strengths and Pollution loads Wastewater Strong liquors Flow BOD (m /day) mg/l 158 Rinse 412 water/General washdown Total 570 kg/d COD mg/l 5,565 897 430 177 - kg/d SS mg/l Total N kg/d mg/l kg/d 9,450 1493 2050 324 250 40 510 210 102 42 36 15 1,056 - 1,073 - 366 - 55 Step 5: Accounting for gaseous emission (assumed that it is not considered) Step 6: accounting for By-Product/Solid waste - Screening: tree skin, leaf contain latex but in a very small amount, dumped onsite - By-Product: + Coagulated latex: reused for block rubber process, not considerable + Skim latex: 7,740 kg/day Step 7: Material balance Inputs Field latex Chemical Water Total Output Centrifuged latex Skim latex Gaseous Wastewater Total kg/d 106,000 476,2 554,000 660,476.2 Overall Centrifugation process kg/d 35,000 7,740 Not considered as a major output 570,000 612,740 15 Step 8: Evaluating the material balance and Suggestion After balancing input and output of the process and refining the material balance, it is showed that there are 47,736.2 kg/d (7.2% of input) lost from the process This may happen due to: - Leaking of field latex on the way from harvesting field to the factory, and from subsequence steps in the process; - Wastewater is leaking from the process; or there are problems in wastewater collecting system, especially is rinse water A part of it may run to the storm water collecting system - Percentage of converting field latex to latex concentrate and skim latex is quite low due to low performance of centrifuge machine, so that large amount of latex is washing out through wastewater To overcome these problems, such measures are proposed i.e.: + Check the field latex collecting step to minimize leaking of field latex + Repair or replace centrifuge machine to improve centrifugation efficiency + Examine wastewater collecting system 6.6 Waste sampling and monitoring 6.6.1 Water quality a Location to take sample: influent and effluent of wastewater treatment plant b Parameters: pH, BOD5, COD, SS, ammonia, N, P, Zn, Al, Mn 6.6.2 Air quality a Location to take samples: main entrance gate, raw material intake area, WWTP, chemical storage house, workshop areas, stack of drying room and downwind areas 200 and 500 meters away from factory b Parameters: PM, CO, NOx, SO2, NH3, H2S, and noise 6.6.3 Applied Standard Following standards of Vietnam (TCVN): Discharge: 5945-1995 (class B) Emission: 5937-1995 (class B), 5938-1995, 5939-1995 6.4 Frequency of monitoring: times/year (at production season) 16 REFERENCES Anil, K.B., Malcolm, M.H., H.A., Benarey, et al (1994) Rubber products manufacturing technology Marcel Dekker, Inc Applied Technique and Production Company (2004) Environmental Impact Assessment report for Xuan Lap latex rubber processing company Dong Nai province, Vietnam Asia, I O and Akporhonor, E E (2007) Characterization and physicochemical treatment of wastewater from rubber processing factory Retrieved March 2007, from Department of Chemistry, Ambrose Alli University, P M B 14 Ekpoma, and Department of Chemistry, Delta State University, Abraka, Nigeria Website: http://homepage.eng.psu.ac.th/chem/File/polngan/2548/vee/1.Treatment%20of%20indu strial%20latex%20wastewater.pdf Central Pollution Control Board CPCB Divisions - Activities Pollution Control Implementation - III Divisions Natural Rubber Processing Industry Website: http://www.cpcb.nic.in/pciiiidivrubber.htm Dong Nai Rubber Company (2004), Monitoring report Xuanlap natural rubber, Dong Nai province, Vietnam Duangporn Kantachote, Salwa Torpee, Kamontam Umsakul (2005) The potential use of anoxygenic phototrophic bacteria for treating latex rubber sheet wastewater Retrieved June 24, 2005, from Faculty of Science, Prince of Songkla University, Thailand Website: http://www.scielo.cl/pdf/ejb/v8n3/a12.pdf http://www.fao.org., 2007 http://en.wikipedia.org/wiki/Natural rubber, 2007 IRSG in http://www.lgm.gov.my/nrstat/nrstatframe.html (2007) 10 Peiris, S (2000) Experience of Cleaner Production elementation in rubber industry and potential for future in Sri Lanka Retrieved March 20, 2007, from Sena Peiris, Cleaner Production Professionals Association of Sri Lanka Website: http://www.uneptie.org/pc/cp/library/training/howtoCPC/manual_cdrom/CPlinks/pdfs/P eiris.pdf 11 Rungruang, N (1998) Treatment of natural rubber processing wastewater by combination of ozonation and activated sludge process (Masters research study No EV-98-32, Asian Institute of Technology, 1998) Bangkok: Asian Institute of Technology 12 Setyamidjaja, D (1993) Karet: Budidaya dan Pengolahan Penerbit Kanisius Yogyakarta 13 Thonglimp, V., Srisuwan, G., and Jkaew (2005) Treatment of industrial latex wastewater by activated sludge system Retrieved May 2005, from Prince of Songkla University, Faculty of Engineering, Department of Chemical Engineering, Hat-Yai, Songkla 90110, Thailand Website: http://homepage.eng.psu.ac.th/chem/File/polngan/2548/vee/1.Treatment%20of%20indu strial%20latex%20wastewater.pdf 17 14 Thongnuekhang, V and Puetpaiboon, U (2004) Nitrogen removal from concentrated latex wastewater by land treatment Retrieved 22 March 2004, from The Joint Graduate School of Energy and Environment, King Mongkut’s University of Technology Thonburi, Bangkok, 10140 Thailand, Department of Civil Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla, 90112 Thailand Website: http://www2.psu.ac.th/PresidentOffice/EduService/journal/26-4pdf/09wastewater.pdf 15 Verhaar, G (1973) Processing of Natural rubber Food and Agriculture Organization of the United Nation 16 C., Visvanathan (2007) Industrial Waste Abatement and Management (Lecture note, Course No ED78.20, School of Environment, Resources and Development) Bangkok: Asian Institute of Technology 18 ANNEXES 19 ANNEX Table World natural rubber production and consumption Year Production (1000 tons) Consumption (1000 tons) 1996 6,440 6,110 1997 6,470 6,460 1998 6,850 6,570 1999 6,872 6,646 2000 6,764 7,383 2001 7,242 7,334 2002 7,303 7,627 2003 7,976 8,003 2004 8,639 8,579 2005 8,821 9,000 Source: IRSG in http://www.lgm.gov.my/nrstat/nrstatframe.html (2007) 20 ANNEX water From rubber plantation Soil rubber 0.5% Scrap 2.5% Latex 97% Left over latex in cup and basket Lump + foam 2% Water Filter Water Mixing tank Water Filter Water Waste water Coagulation tank Milling Smoking Drying Waste from cutting Off crepe Compo Sortation and packing Compo Standard sheet 89% Figure Flow diagram of rubber smoke sheet processing 21 ANNEX Field latex Lump (Bowl lump, soil lump) Ammonia 0.1% Preservation Latex reception (Screen and dilution) Washing Formic acid 2% WW Coagulation WW Milling WW Cutting WW Drying T= 110 – 120oC Export Pressing, Packing and Storage Figure Diagram of crepe rubber processing 22 ANNEX Latex Lump (100%) Pre-breaking Coagulation Hammer milling Filter Calendar hammer milling Drying Weighing Bale pressing Packaging Storage Figure Flow diagram of crumb rubber processing 23 ANNEX Field latex Ammonia 0.1% Preservation Latex reception (screen) Ammonia 98% WW DRC & NH3 determination Centrifugation Skim latex Sulfuric acid Ammonia 98% Coagulation WW Crushing WW Milling WW Cutting WW Concentrated latex Storage Centrifugation Export Drying T= 110 – 120oC Pressing, Packing and Storage Figure Diagram of latex concentrate processing 24 ANNEX Miscellaneous latex Soaking basin (receiving, classifying, soaking and washing out) Water Wastewater Solid waste Electricity Water Coarse pressing and cutting Wastewater Solid waste Electricity Water Chopping small bits Wastewater Solid waste Electricity Water Sheet flattening Wastewater Solid waste Electricity Water Fine chopping Wastewater Solid waste Electricity Water Sheet flattening Wastewater Solid waste Electricity Water Granulating Wastewater Solid waste Arranging, draining Wastewater Electricity Drying Leftover heat Electricity Weighing Electricity Compressing Leftover heat Packing Solid waste Wood Pallet Plastic bag Storage Figure Diagram of miscellaneous rubber processing 25 ANNEX 7: CLEANER PRODUCTION OPTIONS Stages 1) Tapping Cleaner Production Opportunities Technologies - Replacing traditional coconut shells by plastic bowls (2,4) - Replacing traditional galvanize iron buckets by plastic buckets (2,4) 2) Preservation 3) Transportation 4) Coagulation 5) Skim Coagulation 6) Milling 4) Drying Technical training tapers (2,3,4) Coating of epoxy for mild steel bowls to prevent rust to latex (2) Using of wooden planks to cut the coagulum to size (4) - De-ammonization of effluent before skim coagulation to reduce usage of sulfuric acid (3) -Segregation of serum water from latex, centrifuge wash water and bow wash water (1,3) -Recycling of the wash water with a little treatment for selected uses (non-critical operations) (1,2,3) Using of uniform edged laces to reduce the milling needs and blankets and bundles formed take lesser time (1,4) Internal partitioning and systematic passing of hot air from chamber to chamber (1) 5) Scrum Water Notes: Management Practices Technical training tapers (2,3,4) Controlled trials of latex formulation and chemical dosing (NH3, H2SO4) (3,4) Use of scrum water as a liquid fertilizer (with trials)(2) ( ) refers to Benefits, i.e.: Reduction in Energy Consumption Reduction in Pollution Load Reduction in Chemical Requirements/ Utilities Requirements Reduction in Labor/Time and Improvement of Product Quality 26 27 ANNEX 8: WASTEWATER TREATMENT PLANT Grit Equalization Coagulation and Flocculation Neutralization DAF – Dissolved Air Fl i UASB landfill Sedimentation Aeration Treated water Absorption tank Filter Thicken landfill Figure Flow diagram of treatment system adopted 28 ANNEX Centrifuged process Drum screen Skim process Solid maters reused for the process Miscellaneous process General washout Equalization tank C Grid removed Wastewater Figure Xuan Lap wastewater t ... environment, waste abatement and management in natural rubber processing sector should be handled properly This paper is presented to discuss in detail about natural rubber processing sector in terms... latex Soaking basin (receiving, classifying, soaking and washing out) Water Wastewater Solid waste Electricity Water Coarse pressing and cutting Wastewater Solid waste Electricity Water Chopping small... soaking and/ or washing the lump, and then followed by hammer milling, crepe formation, milling, drying, bale pressing, and packing The flow diagram of crumb rubber processing is presented in the