VIETNAM JOURNAL OF CHEMISTRY VOL 51 (3) 373 378 JUNE 2013 SMALL SCALE RICE MILLS ENTERPRISES IN THE MEKONG DELTA THE ENVIRONMENTAL POLLUTION AND REMEDY SOLUTIONS Nguyen Vo Chau Ngan*, Le Van Linh, and[.]
VIETNAM JOURNAL OF CHEMISTRY VOL 51 (3) 373-378 JUNE 2013 SMALL-SCALE RICE MILLS ENTERPRISES IN THE MEKONG DELTA THE ENVIRONMENTAL POLLUTION AND REMEDY SOLUTIONS Nguyen Vo Chau Ngan*, Le Van Linh, and Truong Hoang Dan College of Environment & Natural Resources - Can Tho University, Vietnam Received 14 September 2012 Abstract The Mekong Delta of Vietnam is known as a rice bowl of the country, where produces more than 50% national production ofrice.This sector following by the rice mill enterprises which dehusk and polishrice.Almost Ihe nce Mills in the Mekong Delta are small- or medium-scale enterprises which located inside the residential areas This investigation conducting a survey of current status at 12 small-scale rice null enterprises at Thoi Lai district Can Tho city The survey recorded such of rice mill factories used a diesel engine to nm the milling machines that cause of indoor pollution Beside that, the results showed the negative affects from these activities onto the local commuiuties such as worse air quality, uncontrolled waste and wastewater discharge, unsufficient working conditions, etc Based on that fact, there are some suggestions issuing to inprove the mentioned situation Keywords: Rice mills processing, the Mekong Delta BACKGROUND 1.2 Technical aspect of rice milling I.L Introduction on rice production Broadly defined, rice milling consists of five steps: drying, cleaning, removing the hull, milling, polishing, and sizing - Paddy is dried to 12-^14% to avoid eterioration and improve milling efficiency This may be accomplished by spreading the paddy out in the sun, by using a mechanical drier, or by both methods - Cleaning is remove stones, dirt and other strange materials to increase the value of the final product and avoid damage to milling equipment This is accomplished with a variety of vibrating screens that separate by size and density - The nce hull can be removed by a hulling machine These machines use rotating disks, steel rollers, or rubber rollers to separate the hull and part of the germ - Milling is removing the outer bran layers usmg machines that create abrasion The degree of milling is variable Less milled rice has more bran, making it more nutiitious At the same time, less milled rice is chewier, darker, takes longer to cook, and has a shorter shelf-life As a result, white rice is generally preferred by consumers - Polishing is the removal of the innermost layer of bran This stage is optional, depending on consumer preferences and willingness to pay for whiter rice Vietnam is one of the major rice producing countries and the second largest rice exporter, with milled rice exports reaching 6.8 million tons in 2010 (Gummert et al.) To get the edible rice for consumption or export, the husk and the bran layer need to remove from the paddy grain through the nce miller Rice milling process embraces two basic operations: (i) one operation called dehusking is the removal of the husk to produce brown nce; (ii) the other operation called polishing is the removal of the bran layer from brown rice to produce polished rice Milling also removes the germ and a portion of the endosperm as broken kernels and powdery materials Knowing as a "rice bowl" in Vietnam, the Mekong Delta can supply an estimated million tonnes of rice husk from the rice mill sectors per year According to the survey from the Mekong Delta Development Research Institute - Can Tho University, there was about half of the rice husk from the mills is used for household fuel, fertiliser and other purposes; the other half is disposed of by burning or dumping into rivers and canals that polluting the environment and affect to the health of locaj residence (VNS, 2010) Nguyen Vo Chau Ngan, etal VJCVoL 51(3), 2013 - Grains may be separated according to size usmg two machines Rough sizing can be done with vibrating screens with different sized holes, similar to those used for other grains Finer sizing can be done with screens with thousands of small indentations to pick up individual kernels As the screen is tilted to become vertical, the longest grains are the first to fall out Not all rice mills cany out all of these processing activities Smaller mills usually focus on either shelling or milling (bran removal) Mediumsize mills may clean, shell, and mill, but not polish or grade by size Only the largest mills typically perform all of these tasks environmental noise Beside that, personal interviews with total 67 persons using standard questionaires were carried out Interviewers were divided into three groups: the factory' managers (12 persons), factory's workers (20 persons) and local residents within 100 m from factories (35 persons) Information gathered from interviews helped evaluate the environment affects and environment management conditions of each factory Descriptive analysis was used in interpreting the collected data RESULTS AND DISCUSSION 1.3 Study objectives 3.1 Operation conditions of factories This study aim to evaluate on the kind of pollution, pollution level, how the pollution affect on the local residence, the environment management situations at the rice mill factones in the Mekong Delta Among 12 factories, the earliest factory was found from 1996, the newest one was start from 2011, The grovrth in the number of rice mills was not gradually increasing by time In the period 1996 to 2005, there is one to two factories was bom each year in this area, but from 2005 to 2011 there was only one factory create This figure presents the number of rice millers already sufficient to the demand of this area 2, METHODOLOGY 2.1 The study sites Located in the intensive nce produce area, Thoi Lai district ovming 18 rice milling factories which create around 550,000 tons of milled rice per year By intermix in the residental areas, these factories causes of such environmental problems as solid waste, dust, noise, vibration, etc Based on the technical type, the operation capacity and operation time, surveys were conduct in 12 factories for advance sUidy These factories located at Thoi Lai town (9 units), Thoi Tan ward (1 unit), and Tan Thanh ward (2 units) Most of factories placed at the center area of the district due to easy access of fransportation in both road and waterway, 2.2 Data collection and analysis There is two parameters were onsite recorded at indoor and outside of each factory include ambient air quality (by the SIBATA dust indicator), noise (by the Sound level meter RION NL-21) The indoor values recorded at the running machine position, and the outdoor parameters recorded at the nearby households where within the radius of 100 m from each factory The record methods were following the national standards on TCVN 5067:1995 Weighing method for determination of dust content; TCVN 7878-1:2008 and TCVN 7878-2:2010 Acoustics Description, measurement and assessment of Table 1: Bom-time and capacity of factories No Factory Year of bom 10 11 12 RMOl RM02 RM03 RM04 RM05 RM06 RM07 RM08 RM09 RMIO RMll RM12 1996 1997 1999 1999 2000 2000 2004 2004 2004 2004 2004 2011 Design capacity (ton/year) 30,000 15,000 22,000 18,000 25,000 36,500 20,000 18,000 24,000 36,500 35,000 60,000 Real capacity (ton/year) 18,000 5,000 11,000 10,000 14,000 12,000 7,000 5,000 4,500 12,000 17,500 50,000 Almost real capacity of factories less than the design capacity But the decrease in operation capacity is not corresponding to the operation time of each factory The oldest factory - Phuoc Hung has the real capacity still take part of 60% comparing to the design capacity, while the later factory - Thanh Loi - only get 19% The capacity of each factory depend both on the subjective and the objective factors Normally rice mill factories only reach the design capacity from to months per VJC, Vol 51(3), 2013 Small scale rice mills enterprises year due to the Winter - Spring and the Summer Autumn crops At the other time, they have to active under the design capacity, even stop for equipment repairing For the objective factor, by the age of factories, some of boss did not want to invest for equipment upgrading Due to age of factories, most of equipment have the remained using ratio from 50 to 80%, except the new factory which was build in 2011 And almost assembly line was national manufacture, only some equipment import from foreign countries Within surveyed factories, there is two firms (RM04 and RM09) applying diessel as fuel for system operation Other tens factories (83.33%) running the machine by electricity According to the mention from factories' managers, they could save the operation fee and getting higher operation efficiency with the system miming by electricity In detail, to produce one ton of milled rice, the diessel take about 4.5L while it is take about to kW of electricity significant different It showed that the noise from rice millers not disturb to local community Table 2: The average noise value from factones Unil: dB NTesting Households Households Indoor of NMte at below at front factories wind blow wind blow Factor^ Factories with capacity from 14,000 tons upward RMll 80.1±0.00" 76.6±0.20' 68.9*0.20' RM12 75.9*1.32" 66.3±0.17' 64.3*0.30" RM05 84.7±0.10' 68.2±0.10' 66.6*0.30' RMOl 85.6±0.30' 64.9*0.10" 67.8*0.30" Factories with capacity from 7,000 to 14,000 tons RM03 78.8±0.30" 66.5*0.17' 67.4*0.00" RM06 85.1*0.40" 68.1*0.30" 66.8*0.10" RMIO 85.U0.10" 70.3*0.30' 74.6*0.26" RM04 86.5±0.10" 64.5*0.00" 66.5*0.20' Factories with capacity from 4,500 to 7,000 tons RM07 82,8±0.30' 69.7*0.20' 74.3*0.20' 78.6±0.40' 64.5*0.20° RM08 70.1*0.10" RM02 83.5±0.26" 62.7*0.20' 69.5*0.20' RM09 82.6±0.20' 73.2*0.40" 72.1*0.10' 3.2 The environment situations of factories Notes: the average value ± the SD followed by a commo letter are not significantly different at p < 0.05 based o Duncan's Multiple Range Test (in collumn) Due to big range of factories' capacity, we evaluate the environment conditions of factories by groups of factories' capacity: from 4,500 to less than 7,000 tons, from 7,000 to less than 14,000 tons, and from 14,000 tons upward 3.2.2 Ambient air quality Table 3: The average dust values at nce millers 3.2.1 Noise status Unit: pg/rr^ When the factory running, the average noise value records from indoor of factories and its effect to nearby households at below and front of wind direction shows significant different (p < 0.05) in each group of factones Between groups, the average noise values were not significant different even the factories' capacities range from 4,500 tons to over 14,000 tons It clearly showed the noise is a obvious problem which present at all rice millers The indoor noise of factories ranges from 75.9 to 86.5dB are more less the indoor permission noise value defined in Decision No 3733/2002/QD-BYT promulgating 21 standards of labour sanitation, 05 principles and 07 parameters of labour sanitation In this decision, the noise level equivalent should not higher than 85dB in eight continuous work-hours There are five factories where the noise could affect direct to workers The noise recorded inside and outside the factories are significant different (p < 0.05) But the noise level at 100m distance households in front and below the wind direction from the factory are not Households Households at below at front wind wind blow blow Factories with capacity from 14,000 tons upward 253.30*0.20' RMll 6656.30*1.70' 416.30*0.30" RM12 1265.37*1.25" 180.40*0.40" 150.37*0.20' RM05 2086.50*0.50' 242.30*0.10' 230.20*0.20' RMOl 4612.40*1.60" 321.20*0.30" 285.60*0.60° Factories with capacity from 7,000 to 14,000 tons RM03 3714.17*4.01' 214.30*0.60' 232.53*0.20' RM06 5236,67*3.25" 256.30*0.26' 242.30*0.00' RMIO 3564.50*1.00' 241.30*0.26' 230.50*0.20" RM04 5360.20*1.20" 285.60*0.20" 242.30*0.20' Factories with capacity from 4,500 to 7,000 tons RM07 6859.50*2.00" 235.60*0.30' 224.20*0.17' RM08 4454.20*2.80" 225.60*0.00" 230.50*0.20" RM02 3564.50*2.50' 231.20*0.50' 256.30*0.10' RM09 4240.60*18.2" 221.30*0.10" 251.30*0.40° Indoor of factories Notes- the average value ± the SD followed by a commo letter are not significantly different at p < 0.05 based o Duncan's Multiple Range Test (in collumn) 375 Nguyen Vo Chau Ngan, et al VJCVoL 51(3),2013 For air quality, the average dust values recorded indoor of factories are significant different (p < 0.05) in each group but not significant different between groups According to the Decision No 3733/2002/QD-BYT, the maximum concenfration value of indoor grain dust is mg/m\ There only two factories have the indoor dust concentration pass the standard value which cause of health problems to workers The ambient air quality values at the households m front and below the wind direction were significant different (p < 0.05) in each group and between groups It means the dust from factory may disperse to the downsfream local residents by the wind blow In fact, this is a major environmental concern for rice mills Comparing to the QCVN 05:2009/BTNMT National technical regulation on ambient air quality, the total suspended particulates with aerosol sets of 30Dpg/m' which higher than the recorded values at the downsfream households of factories with capacity less than 14,000 tons But for the factories produce more than 14,000 tons, there are two recorded dust values higher than the standard The factory's capacity may result of air pollution, but not the factory's age 3.2.3 The waste management Within 12 surveyed rice millers, there were one factory apply rice husk as source to produce brick, two factories use nce husk to produce husked wood, other factones just sell or give for free the rice husk as fuel The quantity of nce husk at surveyed rice millers as show in table Table 4: The rice busk situation at factories RMOl RM02 Quantity tons/year 3,600 1,000 RM03 RM04 RM05 2,200 2,000 2,800 10 11 12 RM06 RM07 RM08 RM09 RMIO RMll RM12 2,400 1,400 1,000 900 2,400 3,500 10,000 No Factory Treatment method sell sell, produce huskwood sell sell give for free, produce husk-wood sell, give for free sell produce brick sell sell, give for free sell sell, give for free At present, number of households apply rice husk as fuel decrease much due to convenient in liquid pefrolium gas supply The huge of nce husk cummulative in rice millers which could not treat may unofficial discharge into surrounding canal At all factories, the survey shows poor management conditions on this kind of waste tig I: I be unconfrolied nce husk at factones 3.3 The environment management of factories 3.3.1 Environmental policies execution Among surveyed factories, there are two factones (16.7%) submitted the environmental impact assessment reports and eight factones (66.6%) prepared the environmental protection commitments This is a required procedure to start an mdustrial project according to the Circular 05/ 2008/TT-BTNMT guiding strategic environmental assessment, environmental impact assessment and environmental protection commitment However within ten submitted factones, there were nine factories not implemented the regularly environmental monitoring program as they engaged It showed that the factories' manager did not pay attention on environmental protection conditions Fig 2: The poor nce husk storage VJC, Vol 51(3), 2013 3.3.2 Environmental protection conditions According to response from factories' manager, almost managers claimed their factories in so-so rice husk management, so-so dust and noise treatment conditions (83.33%) However the onsite survey showed different figures on this status The results on dust and ambient air quality as showed in section 3.2 The rice husk management was in poor conditions which cause of rice husk discharge into surrounding canal or even burning at the RM04 factory's storehouse Small scale rice mills enterprises they have no any official equipments to measure pollution sources, but rice millers were not process for undertook environmental monitoring procedure so that they could not prove for their environment conditions Beside that, rice millers' manager did not care on fixing some pollution sources, some of them told that it is take much cost to improve their system but without refunding These points caused a big gap between the rice millers and their nearby communities tJ)) • "W,H" „„ I I Noi good VM- n So-so • •_'.ii.^i I i:'fift;i Good ,i«.,; Fig 3: Viewpoint from the factories' managers To reply on working conditions, 50% of survey workers mentioned about high level of noise and 65% complained on high level of dust This evaluate somehow different to response of noise worse than dust from factories' manager Working at rice millers in eight hours with high level of noise and dust may affect to workers In this connection, Lim et at (1998) suggest that a distinct clinical syndrome of the rice mill workers seems to be associated with exposure to rice husk dust Fig 6: The old equipment at one rice miller 4, CONCLUSION AND RECOMMENDATION LJ So-so • High Noise level Dust level Fig 4: Comments from rice miller's workers The local residents had disadvantage comments on environmental protection response by factories There were 27% feedback on poor react, 70% at soso react and 3% at good response to environmental protection The recorded values on outdoor noise and ambient air quality showed some factories may affect to local residents From local residents side, A onsite survey at 12 rice millers in Thoi Lai show environmental problems at some factories The noise and ambient air quality at some factories are higher than the permission values in national standards not only affect to workers but also the local communities Beside the objective reasons, there were subjective reasons which cause of above mentioned problems There were factories have no submitted the environmental protection proposal, and factories did not implemented the regularly environmental monitoring program as they engage^ The negative response from rice miller owner to their technical and management works caused of unpleasant to local community To minimize the environmental problems in this Nguyen Vo Chau Ngan, etal VJC, Vol 51(3), 2013 sector, the following cleaner production measures are particularly relevant for rice mills: - Good and adequately maintained drainage to facilitate run-off and minimize the likelihood of flooding, - Regular inspection of bulk storage tanks to minimize the risk of surface water pollution, - Separation of milling areas from all other areas of operation, - Walls are designed to preyent accumulation of dust and entry of rodents, birds, or pests, - Adequate ventilation to prevent dust pollution and reduce heat, - Prevention of build up of dusts on machinery and ledges, and in the building, - Regularly measures to confrol noise levels and ambient air quality at indoor and the site boundary, - Treatment of effluents discharges, - Re-use of rice husk as fuel for paddy drying, steam generator, or gasifier, - Sale rice husk to only confrolled burning site REFERENCES I Gununert M., Cabardo C and Phan V T Workshop on paddy storage for the Mekong Delta Retrieved at http://irri ,org/index ,php?option=com_k2&vie w=item &id=11424:workshop-on-paddy-storage-for-themekong-deIta&Iang=en H H Lim, Z Domala, S Joginder, S H Lee, C S Lim, C M Abu Bakar Rice millers' syndrome: a preliminary report, Br J, Ind Med., 41, 44549(1984) doi; 10.1136/oem.41.4.445 VNS Rice husks may fuel Cuu Long, (2010) Retrieved at htlp://victnamnews.vnagency.com.vii/ AgricuImre/196409/rice-husks-may-fueI-cuu-longmekong-.html Corresponding author: Nguyen Vo Chau Ngan College of Environment and Natural Resources - Cantho University 3-2 sfreet, Xuan Khanh ward, Ninh Kieu dishict, Can Tho city, Vietnam Email: nvcngan@ctu.edu.vn ... 10.1136/oem.41.4.445 VNS Rice husks may fuel Cuu Long, (2010) Retrieved at htlp://victnamnews.vnagency.com.vii/ AgricuImre/196409/rice-husks-may-fueI-cuu-longmekong-.html Corresponding author: Nguyen... their nearby communities tJ)) • "W,H" „„ I I Noi good VM- n So-so ã ã_''.ii.^i I i:''fift;i Good ,iô.,; Fig 3: Viewpoint from the factories'' managers To reply on working conditions, 50% of survey... small indentations to pick up individual kernels As the screen is tilted to become vertical, the longest grains are the first to fall out Not all rice mills cany out all of these processing activities