Development of National Emission Standards for Pesticides Manufacturing Industry

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Comprehensive Industry Document Series (COIN

COINDS/73/2007

DEVELOPMENT OFNATIONAL EMISSIONSTANDARDS FOR PESTICIDESMANUFACTURING INDUSTRY

ZFDF C LE A N

CENTRAL POLLUTION CONTROL BOARDMINISTRY OF ENVIRONMENT & FORESTSWe.bsite: www.cpcb.nic.in e-mail: [email protected]


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Com prehensive Industry Documen ts Series (COINDS)

COINDS/73/2007

D E V E L O P M E N T O FNATIONAL EMISSIONSTANDARDS FOR PESTICIDESMANUFACTURING INDUSTRY

m e i ` 'c'tbCENTRAL POLLUTION CO NTRO L BO ARDMINISTRY OF ENVIRON MENT & FORESTS

e-mail : [email protected] Website: www.cpcb.nic.inMay 2007


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CPCB, 250 Copies, 2007

Published By : Dr. B. Sengupta, Member Secretary, Central Pollution Control Board, Delhi 32Printing Supervision & Layout: P.K. Mahendru and A namika SagarC omposing & L aser Typesett ing : Suresh C hander SharmaPrinted at: DSIDC , Ne w Dellhi.


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Q-r .93}TTA..3it2l8iJ. M. MAUSKAR, la sChairman

(z ter1 T TPCentral Pollution Control Board(A Govt. of India Organisation)Ministry of Environment & ForestsPhone 22304948/22307233F OR E WOR D

Pesticide Sector comprises many processing units which adopt different technologies,equipments, unit process and unit operations for manufacturing various products. Themanufacturing processes lead to generation of a wide spectrum of air pollutants, mainlyinorganic hazardous air pollutants. Some of these pollutants are toxic, responsible fordamage of materials and creation of malodour. Besides these hazardous air pollutants,volatile organic compounds (VOCs) mainly solvents are generated as fugitiveemissions. Volume of VOCs in Pesticide units are quite low in comparison to VOCsgeneration in petrochemical and oil refinery, however.In order to reduce the air pollutants emissions to an acceptable level, it is necessary toadopt a comprehensive approach considering possible thermal destruction, recovery ofchemicals, good engineering practices and end-of-pipe technology with due regard totechno-economical feasibility within the framework of National Environment Policy(NEP), 2006. The salient features of NEP with respect to standards are as below:

(a) Gene ral availability of required technology and techno-econ omic feasibility;(b) Risk reduction related to health, ecosystem and manmade assets; and(c) Ensure to achieve the ambient air quality standard (location specific).Within this backdrop, the Central Pollution Control Board in association with M/sShriram Environment & Allied Services, Gurgaon, took up a study to develop NationalEmission Standards for the Pesticides Manufacturing Industry.My colleagues Sh. G. Thirumurthy, Assistant Environmental Engineer, Dr. -0. D. Basu,Senior Scientist were involve d in preparation, evaluation and finalisation of this Report.Sh. N. K. Verma, former Additional Director coordinated the project. The preparationand finalisation of this Report has been done under the overall supervision ofSh. P. M. Ansari, Additional Director and Dr. B. Sengupta, Member Secretary.Necessary support and inputs provided by the representatives of the Pesticideindustries and by various Experts during the finalisation of this Report need dueacknowledgement. Secretarial assistance rendered by Sh. Atul Sharma is alsoappreciated.I hope that the information contained in this Report will be useful to the RegulatoryAuthorities, the Pe sticide Industry and all other conc erned abo ut pollution in this Sector.

(J. M. Mausk^r)May, 2007

'Parivesh Bhawan' C.B.D.-cum-Office Complex, East Arjun Nagar, Delhi-110 032Fax . 22304948 / 22307078 email : [email protected] : http://www.cpcb.nic.in


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CONTENTS

S. No. Items PageNo.

List of Contents iList of Figures IvList of Tables viList of Abbreviations vii

1.0ntroduction 11 .1 Pesticide Use 21 .2 Pesticide Production in India 2

2.0anufacturing Process 62.1 Acephate 82.1.1ssociated air pollutants 92.2 Aluminium Phosphide 1 02.2.1ssociated air pollutants 1 1

2.3 Captafol 1 12.3.1ssociated air pollutants 1 22.4 Captan 1 22.4.1ssociated air pollutants 1 42.5 Cypermethrin 1 42.5.1ssociated air pollutants 1 6

2.6 Dimethoate 1 62.6.1ssociated air pollutants 1 72.7 2,4 Dichlorophenoxy Acetic Acid (2,4-D ) 1 92.7.1ssociated air pollutants 1 92.8 Dichlorvos (D.D.V.P.) 20

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S. No.tems PageNo.2.8.1ssociated air pollutants 202.9 Ethion 212.9.1ssociated air pollutants 222.10 Endosulphan 23

2.10.1ssociated air pollutants 232.11 Fenvalterate 242.11.1ssociated air pollutants 292.12 Malathion 29

2.12.1ssociated air pollutants 312.13 Methyl Bromide 31

2.13.1ssociated air pollutants 322.14 Monocrotophos 322.14.1ssociated air pollutants 332.15 Isoproturon 34

2.15.1ssociated air pollutants 352.16 Phosalone 35

2.16.1ssociated air pollutants 362.17 Phorate 382.17.1ssociated air pollutants 382.18 Phosphamidon 40

2.18.1ssociated air pollutants 402.19 Zinc Phosphide 41

2.19.1ssociated air pollutants 413.0ir Pollutants from Pesticide Industry 433.1 E missions P rofi le in Pesticide Industry 43

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S. No. Items PageNo.

3.2 Solvents 443.3 Prioritisation of Air Pollutants for Control 463.4 Toxicity and Health Impact of Priority Pollutants 46

4.0vailable Control Technology to Prevent and Control of Air 48Pollutants from Pesticide Industry4.1 Principle of Air Pollution Control Technology 48

4.1.1eparation techniques 484.1.2hermal destruction 484.1.3onversion to harmless product 494.1.4ombination approach 49

4.2 Control Technologies Adopted in Indian Industries 514.3 Efficiencyvaluationfxistingollutionontrol 52Technology4.4 Description of Various Treatment Technique 544.4.1bsorption 544.5 Condensation 6 04.6 Chemical Reaction 6 04.7 Incinerator Technology with Air Pollution Control Devices 6 04.8 Adsorption 61

5.0n Approach for Development of Emission Standards for 63Pesticide Industry5.1 Introduction 6 35.2 Best Practicable Approach (general availability to required 6 3

technology and techno-economic feasibility)5.3 Emission Standards with respect to Location Specificity 7 35.4 Emission Standards 7 55.5 Guidelines for Fugitive Emission Control 7 65.6 LDAR for Pesticide Industry 7 7Bibliography 7 9

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LIST OF FIGURES

S. No. Figure Page No.1 Typical Unit Operations of Chemical Synthesis 72 Process Flow Diagram of Acephate Manufacturing 93 Processlo wiagramfluminiumhosphide 1 0Manufacturing4 Process Flow Diagram of Captan Manufacturing 1 35 Process Flow Diagram of Cypermethrin Manufacturing 1 46 Process Flow Diagram of Dimethoate Manufacturing 1 87 Process Flow Diagram of 2,4-D Acid Manufacturing 1 98 Process Flow Diagram of D. D. V. P. Manufacturing 209 Process Flow Diagram of Ethion Manufacturing 22

1 0 Process Flow Diagram of Endosulphan Manufacturing 241 1 A Process Flow Diagram (Step PCT to D/PCBC) 251 1 B Process Flow Diagram (Step D/PCBC to C/PCCN) 251 1 C Process Flow Diagram (Step C/PCCN to D/PCAN) 261 1 D Process Flow Diagram (Step D/PCAN to D/PCACI) 271 1 E Process Flow Diagram of Fenvalerate (Step D/PCACI to 28Fenvalerate Technical)

12 Process Flow Diagram of Malathion Manufacturing 3013 Process Flow Diagram of Methyl Bromide Manufacturing 311 4 Process Flow Diagram of Monocrotophos Manufacturing 331 5 Process Flow Diagram of Isoproturon Manufacturing 34

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S. No. Figure Page No.1 6 Process Flow Diagram of Phosalone Manufacturing 371 7 Process Flow Diagram of Phorate Manufacturing 391 8 Process Flow Diagram of Phosphamidon Manufacturing 4119 Process Flow Diagram of Zinc Phosphide Manufacturing 4220 Available Techniques for End-of-Pipe Treatment of Waste 50Gases fromhemicalndustries inelation to Type ofContaminants21 Packed Tower Gas Scrubber 5622 Plate Tower Gas Scrubber 57

23 (a) Spray Tower Gas Scrubbers 58to (c)24 Liquid Jet Scrubber 5925 Agitated Tank Gas Scrubber 5926 Flowhartepictingethodologyorestracticable 65Means

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S.No.

Table PageNo.

1 Actual Production of Technical Grade Pesticides 22 Installed Vs Production Capacity of various Pesticides 33 Production of Technical Grade Pesticides 44 State-wise installed capacity Vs Production 55 Product and Associated Priority Pollutants 436 List of Solvents used in Manufacturing Process of Pesticides 447 Properties and Health Impact of Some Priority Pollutants 478 Control Technologies adopted in Indian Industries 519 Suitable Control Systems for Priority Pollutants 53

1 0 Incinerator Technology adopted by Pesticides Industries 6111 Air Pollution Control Devices for Controlling Different Pollutants 611 2 Typical Data for Adsorbent Material and their Use 621 3 Comparison of Control System for Identified Pollutants 6 61 4 Comparison of Best Practicable Technology for Pollutants 711 5 AB/AT Ratio for Various Pollution Control Systems 7 21 6 Controlystem0tackeightax.chievable 7 4

concentration1 7 Controlystem0tackeightax.chievable 74

concentration1 8 Proposed Emission Standards for Pesticides Manufacturing and 75Formulation Industry1 9 National Emission Standards for Pesticides Manufacturing and 76

Formulation Industry

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Abbreviation Full NameRC N AcetonitrileCMAC Cypermethric acid chlorideCMCB Chloro Methyl Chloro BenzoxazolaneDAA Diethyl aceto acetamideDCDAA Dichloro diethyl aceto acetamideDDPA Dimethyl dithio phosphoric acidDE M Diethyl maleiateD E T C Di-ethyl Thiophosphenyl ChlorideDHPD Diethyl hydroxy methyl phosphoric dithioateDMA Dimethyl AmineDMPAT Dimethyl thio phosphoramideDM S Dimethyl sulphateD V A C I 3-(2,2-Dichlorovinyl) 2,2-dimethyl-cyclopropone carboxylic acid

chlorideE DC Ethylene dichlorideHMCB Hydroxy methyl chloro benzoxazaloneMCAC Mono chloro acetic acidM C U Mono cumanyl ureaM -DTCI Dimethyl phosphorochloride athioateMMAA Mono-methyl aceto acetamideM M A C I Mono chloro monomethyl aceto acetamideMMCA Methyl Monochloro AcetateMPBAD Meta phenoxy benzaldehydeN a -DDPA Sodium dimethyl dithio phosphoric acidOA P Ortho ameno phenol

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P A C I Perm ethrin acid ch loridePC A (4-chloro ph enyl) isovaleric acidP C A C I (4-chloro p henyl) isovaleric chlorideP C A N (4-chloro p henyl) isovaleronitrideP C B C p-chloro ben zyl chlorideP C C N p-chloro benzyl cyanidePC T Pera chloro tolueneT C A C Trichloro Acetyl ChlorideTC E Tr i -chloro E thyleneT C E S C I Tri chloro Ethyl Sulphonyl ChlorideT C P N a Sodium S alt of TC A CTHPA Tetra hypo pthaticamideTMP Trimethyl phosphite

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1.0 INTRODUCTIONThe word pest comes from the Latin word "pestis" which includes an animal orplant that occurs in such abundance as to present a distinct threat, economicallyor medically to man or his interest. A pest may be insect, fungus, weed, rodent,bacteria, virus, nematodes, acarid / mite, parasite and even animal or bird.Worldwide, about 10,000 species of insects are important as pest, out of 750,006identified species. Over 50,000 species of fungi are responsible for some 1,500plant diseases; Over 1,800 species of weeds out of the known 30,000 causeserious economic loss. About 15,000 species of nematodes produce more than1,500 serious deleterious effects on plants. Over 1,00,000 species of pestsdestroy food which could be food for 135 million people. The word pest has nobiological meaning. Pests are organisms that diminish the value of resources inwhich we are interested.In India, crops are affected by over 200 major pests, 100 plant diseases,hundreds of weeds and other pests like nematodes, harmful birds, rodents andthe like. About 4,800 million rats cause havoc in India. Approximately, 30% ofIndian crop yield potential is being lost due to insects, disease and weeds whichin terms of quantity would mean 30 million tones of food grain. The value of totalloss has been placed at Rs 50,000 million, represents about 18% of the grossnational agriculture production. The pest wise losses are as follows:

Pestoss of Food Grains (% )Weeds 28Diseases 25Insects 23Storage 1 0Rats 8Others 6

Besides the agriculture, non agriculture pests are carriers of malaria, filaria,encephalitis, typhus, plague and other dreadful diseases. About 30 householdpests are worthy of attention, like files, fleas, bedbugs, lice, cockroaches, mites,termites and moths. Man's war against pests is perennial and almost eternal. Noagriculture or forest crop can be grown in an insect and disease freeenvironment. Pests and disease are parts of natural processes that are going onsince the beginning of the universe, and the biological process of evolution.Total extermination of pests is not possible and is no longer the aim of pesticideapplication. The control of pests is the objective and designated as plantprotection. The efficient producer wants to keep loss due to pests to a minimumpest control is now the chemistry of human survival.


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While pest control is one of the imperative prerequisite, it bears also higherdegree of negative impacts on environment. Since the chemicals which controlthe pest commonly known as pesticides. Pesticides are basically toxics andpersistence, it can enter in food chain and causes injury to human health. It alsodestroys the diversity and food web and causes ecological imbalance. Pestcontrol therefore needs regulation on the interest of human health andenvironment.1esticide UsePesticides are defined as the substance or mixture of substances used toprevent, destroy, repel, attract, sterilise, stupefy or mitigate any insects.Generally pesticides are used in three sectors viz, agriculture, public health andconsumer use. The consumption of pesticide in India is about 600 gms. / hectare,where as that of developed countries is touching 3000 gms. / hectare.There is a wide range of pesticides found used in non-agriculture situations suchas industries, public health and for a number of purposes in the home. Domesticuse of pesticides is mainly as fly killer, ant killer, moth killer, repellants,rodenticides and fungicides etc. By and large industrial use of pesticide is ofvital importance in the industries such as wood and carpet, wood preservation,paint industry, paper and board industry, leather industry, building industry,miscellaneous industrial application e.g. soluble cutting oils, industrial watersystems, drilling fluids etc.2esticide Production in IndiaPesticide is manufactured as technical grade products and consumablepesticides are then formulated The installed capacity of technical grade pesticidewas 1,45,800 tonnes during March 2005, and the production in the financial year2004-05 was 94,000 tonnes. The year wise actual production during year 2001 to2005 was given at Table 1.

Table 1: Actual Production of Technical Grade PesticidesS.No.

Financial Year Production(Tonnes/Year)

AnnualGrowth (% )

Overall Annual Growth(2004-05)/(2001-02)

1 . 2001-2002 81,80014.9%2. 2002-2003 69,600 -153. 2003-2004 84,800 21.8

4. 2004-2005 94,000 10 .8Source: Annual Report 2005-06 of Ministry of Chemicals & fertilizers, Department of

Chemicals & Petrochemicals, page no 54-55


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The annual growth of pesticide production between the years 2001 to 2005 was14.9%. The productions of various categories of technical grade pesticides againstthe installed capacity during the year 2004-05 in India are summarized in Table 2.

Table 2: Installed Vs Production Capacity of various pesticidesS.No. Pesticides Capacity (T/Y) Production

VsInstallation

Distributionof variouspesticidesnstalled Production

1 . Insecticides 1 0 4 20 0 63100 60.6% 67.13%2. Fungicides 26200 22800 87.0% 24.25%3. Herbicides 1 7 0 0 400 23.6% 0.43%4. Weedicides 1 0 1 0 0 59 0 0 58.4% 6.27%5. Rodenticides 3200 1 7 0 0 53.1% 1 . 8 1 %6 . Fumigants 400 1 0 0 2.5%

Total 1 4 5 8 0 0 9 4 0 0 0 1 0 0 %Source: Annual Report 2005-06 of Ministry of Chemicals & fertilizers, Department of Chemicals

& Petrochemicals

From above table, the percentage distribution of various categories of technicalgrade pesticides are insecticides (67%), Fungicides (24%), Weedicides (6%) and theothers Herbicides, Rodenticides, Fumigants (3%). The table clearly indicates that inIndia the production of insecticides is very high compared to the other types ofpesticides. The list of technical grade pesticides manufactured under various typesin India during the year 2004-05 is given at Table 3. The technical-grade pesticidesmanufactured are registered under the Insecticides Act, 1968 in India.Information compiled from the Monitoring and Evaluation Division, Department ofChemicals & Petrochemicals, Ministry of Chemicals and Fertilizers reveal that in thepesticide sector, Gujarat has in installed capacity of 77.68 MT but produces about36.05 MT, followed by Maharashtra with installed capacity of 41.08 MT butproducing about 32.16 MT, Andhra Pradesh produces 2.655 MT against an installedcapacity of 3.4 MT, Kerala producing 2.407 MT against an installed capacity of 4.594MT and Karnataka producing 0.911 MT against installed capacity of 3.9 MT. This issummarized in Table 4.

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Table 3: Production of Technical Grade PesticidesS.No. Name of the Pesticide Type

_ Capacity ( 000' MT)Installed P rodu c tion1 . D.D.T Insecticides 6.3 4.02. Malathion 11.9 4.73. Parathion 4.0 1.04. Dimethoate 3.2 0.95. D.D.V.P 4.3 5,0

0.99.5

6 . Quinalphos 4.07 . Monocrotophos 13.98 . Phosphamidon 3.99 . Phorate 8.2 _0.43 .61 0 . Ethion 5.6 1 .81 1 . Endosulphan 10 .1 3.11 2. Fenvalerate 2. 7 0 . 61 3. Cypermethrin 5. 9 6.51 4 Anilophos 1 .1 041 5. Ace hate 6.1 6 .11 6 . Chlorpyriphos 8.6 9.01 7 . Phosalone 1.0 0.51 8 . Metasystox 0.61 9 . Abate 0.020 . Fenthion 0.2-- - ----------21 . Triazophos 29

0.4- ---- ---- -- -2. Lindane 1.4------0.2-------- -3. Terne hos 0.3-------------- ---0 . 44. Deltamethr in 0.525. Alphamethrin 1.3 0.326 . Ca tan & Ca tafol Fungicides 1.8 0.927 . Ziram 0.5 0.328 . Carbendzim 1.5 0.729 . Calixin 0.2 0 .130 Mancozab 20.7 ----------2 0.831 . C on - ox chloride 1.5 ---- 0.0-- ----- ------32. 2,4- D Herbicides 1.2 0 .133. Butachlor 0.5 034.71.0_34. Isoproturon Weedicides

------- -----

5.435. Glyphosate 3.936 . Para uat -- 0 .0---- ----37 . Diuron 0 .1 0.00.00.2------- -- -- -

38 . Atrazine 0.50.2 ---

9 . Fluchloralin40 . Zinc Phosphide Rodenticides 0.9 0 .311 . Aluminium Phos hate 2.342. Methyl Bromide Fumigants 0.2 0.043. Dicofol 0.2 0.1Total 145.7 94.0source: Annual Report 2005-06 of Ministry of Chemicals & fertilizers, Department of Chemicals & Petrochemicals


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Table 4: State wise Installed capacity Vs Production

S.No. Name of the Installed ActualState capacity Production

(MT/Year ) (M T/Year)1 . G ujarat 77.68 36.052. M aharashtra --- 41.08- - - - - 3 2.1 6---------3. Andhra 3.4 2.665Pradesh4_ Ke rala 4594 ---- 2.407__---5. Kar nataka 3.9 0.9 1 1Source: Annual Report 2005-06 of Ministry of Chemicals & fertilizers, Department of Chemicals& Petrochemicals


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2.0. MANUFACTURING PROCESSPesticides are produced by chemical reactions of organic materials, which seldom go tocompletion. The degree of completion of organic reaction is generally very much lessthan those involving inorganic reactions. The law of mass actions states that in order totransform one reactant fully, the other reactant must be present far in excess in weightthan the stoichometric requirement. This law is applied in practical field. As a result, thefinal mass of an organic reaction is associated with not only the desired product, but alsountreated reactants and undesired products of side reactions or partially completedreactions. The manufactures of pesticide is hardly accomplished in one reaction, in mostcases, it involves various unit processes and unit operations.The important types of unit process (chemical reactions) are:olkylationoarboxylationocetylationoondensationoyclization,oDehydrationoalogenationoOxidationoulfonationoitrationominationAlso, the important types of unit operations (physical) are:oiquid / Liquid extractionoiquid / Liquid separationoiquid / Solid separationoGas / Solid separationoDistillationorystallizationoGas obsorptionoDryingoGrindingoMixingIn each reaction, state some raw material remain un-reacted, and some unwantedproduct are formed which remain in the system. Desired products are carefullyrecovered in each step from the system. Unwanted products are discarded, but notcarefully. These inevitably become pollutants in wastewater and solid waste. Some arevented out in the atmosphere. Although in some cases some recyclable materials arealso profitably taken back in to the system. Impurities present in raw materials may alsoreact with one another and in many cases show up as a scum, froth or tar or simply asun-reacted raw material. In order to understand generation of wastewater, solid wasteand emission understanding of unit process and operation is required. The typical unitoperation of chemical synthesis is depicted in Fig. 1. Within this backdrop themanufacturing process of some of the technical grade pesticides and associated airpollutants are discussed in the subsequent paragraphs.

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EnergyOil ,coal, natural gas,electricity, steam etc

Thermo oil, pressurisedair, hydraulic oil, etc

Auxiliary media 1Stich ascaYsacids,alkaline, neutral saltswhich don't take partingthe chemical reaction

Chemical Auxiliaries

Recycling especiallyeciChemical Rawf catalystsmaterials Chemical operationsprocess/ reactions and UnitroductsOperations I By Products forinternal or external useL-----------------------------------on reacted rawmaterials recovery

and reuse possible

I Waste Heat IGaseousWastages

Usually different defined sources with certain flowand compositon - to treat with / without reuseSolid W aste

Wa ste Water\aually different defined sources with certain flow andcomposition - to pre-treatment and final treatment,sometimes with reuseFig.1: Typical Unit operations of Chemical SynthesisWa ter7


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2.1. AcephateProcess starts with the addition of Dimethyl Sulphate to Dimethyl thio phosphoramide(DMPAT) to give Methamodophos, which is acetylated with acetic Anhydride in presenceof sulphuric acid to give crude acephate. Crude acephate is neutralised with ammoniasolution and extracted in methylene chloride. The extracted acephate liquor iscrystallised under chilled condition in presence of Ethyl acetate. Crystallised Acephateis then centrifuged and dried. The chemistry of Acephate production is stated below:

Step 1: Isomerisation

CH 3 C0P NH S

CH 3 COD M P A T

+ DMSDienethylSulphate

C H 3 C O7 0 C\ II---P-NH2CI-i3CSMethamodophose

Step 2:Acetylation

C 1 - 1 3 C0//2 P NH2Cl 3 C SMethamodophose

0CH 3 -C 65-70C

+H2SO4CH3-CI 10 CH 3CO001 11P-N-C-CH 3 + CH 3 000HCH3 C S HAcetic AnhydridecephateStep 3: Neutralisation & Extraction of AcephateLiquor ammonia is slowly added under stirring to neutralize sulphuric acid and aceticacid. Liquor ammonia is added till pH is about 7. Layers are separated. Organic layer iswashed with water. Aqueous layer is sent to effluent treatment plant.

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Step 4: Crystallisation of Acephate LiquorOrganic layer is subjected to vacuum distillation to recover methylene chloride. Afterrecovery of methylene choloride, mother liquor is taken in a crystallizer. Ethyl acetate isadded, stirred and crystallized Acephate is allowed to settle. Acephate is filtered andmother liquor is taken for ethyl acetate recovery. Viscous organic mother liquor afterethyl acetate recovery is sent for incineration. The process flow diagram of Acephate isgiven in Fig. 2.

DM PATD MSMethylenechlorideSOMERISATIONMcC1 2A n hydrideCETYLATIONAmmonia_NEUTRALISATIONLiquor

McC12XTRACTION(Recycle)Ethyl AcetateRYSTALISATION McCl2 (Recycle)Sulphuric Acid^ Aqueous Phase[1 ] Acetic Acid (50%)[2 ] Ammonium SulphateCENTRIFUGATION

ACEPHATE W/C

Fig. 2: Process Flow Diagram of Acephate Manufacturing

2.1.1 Associated Air PollutantsThere is no channelised emission observed in the process of Acephate manufacturing.Because, process steps for preparation of Dimethyl thio phosphoramide (DMPAT) hasbeen eliminated / stopped, which is the source of HCI emission as data received fromthe industrial units manufacturing Achephate.

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2.2luminium PhosphideAluminium phosphide is manufactured by reacting Aluminium and Phosphorus in aclosed chamber. Aluminium phosphide is formed, instantaneously liberating heat ofreaction. The Aluminium phosphide thus obtained, is reduced to required size, blendedwith inert ingredients and converted into various tablets and pouches.The process flow diagram of Aluminium phosphide is shown in Fig. 3.

ALUMINIUMPOWDER WATER PHOSPHORUSMELTERTRANSFER WASTEWATER

TO ETP

MIXINGUNITent P 2 0 5 (as H3 PO 4 mist)1H3PO4

ABSORBERY PRODUCTL WASTEWATER TO ETPUrea/MR-17

Zn StGRAPHITE

CRUSHING

WAX

BLENDING

SEINING

TABLETING POUCHING

P A C K I N GAluminium Phosphide

OVER SIZERECYCLE

Fig 3. : Process Flow Diagram of Aluminium Phosphide Manufacturing


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2.2.1. Associated Air PollutantsDuring the course of reaction, P205 fumes (as H3PO4 mist) generated, which arepass through scrubber, followed with mist eliminator so as to control the emissionof pollutants. Also, dilute phosphoric acid is generated as a by-product by theindustrial units.

2.3aptafolSulphur is charged in reactor then chlorine is slowly passed at controlledtemperature (55 to 60 C) to form sulphur Mono Chloride. Again Chlorine ispassed through Sulphur Mono Chloride to convert it to Sulphur Dichloride.Sulphur Dichloride is added to hot (86 C) Trichloro Ethylene & then Misture isheated to 135C to form .Tetrochloro Ethyl Sulphomyl Chloride (TCESCL), whichis then washed with water and diluted with Toluene. Finally TCESCI iscondensed with Tetra hydro phthalic imide (THPI) in presence of NaOH to giveCaptafol, which is centrifuged & dried.The steps of chemical reactions for Captafol manufacturing are as follows:Step 1:ulphur Mono Chloride Preparation2S+l2SzCl2Sulphurhlorineulphur MonochlorideStep 2:ulphur Dichloride Preparation

S2Cl20122SC12SulphurhlorineulphurMonochlorideichlorideStep 3:etrachloro Ethyl Sulphonyl Chloride Preparation (TCESCI)Cll^C=C 6 HCI + H 2 SO 4 + 6 HCI + CSCI 4

Step 2:ashing & Dilution of CSCI 41 2


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Step 3:ondensation 0I IIlC S C I 4 + NaOH +H-S C--CI -1 N aC

OTetra Hydro Pthelic AmideaptanStep 4:ashingStep 5:iltration & DryingProcess flow diagram for manufacturing of Captan is given in Fig. 420% NaOHC S zHC IC R U B B E RE TPEDO TLHLORINATIONWaterWaterSCI4queous Phase to ETPWashina

TolueneSCI4dilutionTHPINaOHONDENSATIONH 2 O Recycled MLWeWASHINGo- A queous Phase to E TP

FILTERATIONL to Recycle& DRYIN GCAPTANI

Fig. 4: Process Flow Diagram of Captan Manfuacturing

1 J


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2.4.1 Associated Air PollutantsThe air pollutants identified from the process of manufacturing of Captan areHydrochlor ic A cid (HC I) and C hlorine (C 1 2 ) .

2.5 CypermethrinDichloro Vinyl Cyclo propane Carboxylic Acid Chloride (DVACI) also known asCypermethric Acid Chloride (CMAC) and Meta Phenoxy Benzaldehyde (MPBAD)are taken in an agitator reactor, in a solvent (Hexane). Sodium cyanide andwater are added to the mass. Mass is agitated in reactor for the required time. Atthe end of reaction, the reaction mass is separated into two phases, organic layerand aqueous layer.Organic layer containing the product, Cypermethric technical with solvent istaken for distillation, where the solvent is removed and recycled. The final tracesof solvent, which are around 3-4%, are removed under vacuum and recycledback. The process flow diagram is shown in Fig. 5.

NaCN, H 2O,MPBAD, TEA

DVACI, Hexane 1-CYPER REACTIONIq. CN - LAYER Cyanide Treatment)

CYPER + HEXANE1st Water wash1st Soda wash2nd Soda wash2nd Water wash

2-WASHINGI AqCYPER + HEXANE

CN LAYER (Cyanide Treatment)

Rec. HEXANE. (Recycle)

3-CONCENTRATION

CYPER TECH.

Fig. 5: Process Flow Diagram of Cypermethrin Manufacturing

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DVA chlorideAcrylonitrile and Carbon tetrachloride are reacted in presence of catalyst to giveTetrachloro butyronitrile (TCBN) and the same is taken for distillation. PurifiedTCBN is hydrolysed with Sulphuric acid to form Tetra chloro butyric acid. Thespent acid is separated, taken for despatch. TCB acid is reacted with Thionylchloride to make TCB Acid chloride. The gases liberated are scrubbed withwater to remove HCI and with Caustic to remove S02. TCBACI is taken fordistillation.Distilled TCBACI is reacted with Isobutylene in presence of Tri Ethyl Amine tomake 2-Cyclobutanone (2-CB). After recovery of solvent, it is taken for filtration.Mother liquid is taken for recycle. 2-CB powder is isomerised in presence ofcatalyst to give the derivative of 4-Cyclobutanone (4-CB).4-Cyclobutanone thus obtained is reacted with Caustic solution to form Sodiumsalt of DVA. DVANa is acidified with HCI to make DV Acid. DVA is furtherreacted with Thionyl chloride to obtain DVA chloride. The gases liberated arescrubbed with water to remove HCI and with Caustic to remove S02. DVAchloride thus obtained is taken for solvent recovery followed by distillation tomake purified DVA chloride.Metaphenoxy benzaldehyde (MPBAD)Benzaldehyde is reacted with Bromine and chlorine in presence of EDC to formMeta Bromo Benzaldehyde (MBB). HCI generated during the course of reactionis scrubbed in water to form HCI, which is recycled. Reaction mass is washedwith HCI (3-4%). AIC1 3 solution formed during the wash is sold after treatment.Organic portion from above wash is treated with thio sulphate and given a waterwash. Organic layer containing MBB and EDC is taken for distillation. CrudeMBB thus formed is then fractionally distilled to get distilled MBB. EDC and midfractions recovered during the distillation are recycled. Distilled MBB is thenreacted with Mono Ethylene Glycol in presence of catalyst to form Meta Bromobenzaldehyde acetal (MBBA).MBBA is reacted with phenol in presence of catalyst, KOH and Toluene to formMeta Phenoxy benzaldehyde acetal (MPBA). MPBA is further treated withcaustic lye in presence of water. Aqueous layer is separated from organic layerand treated with sulphuric acid. KBr solution formed during the course oftreatment is then taken for Bromine recovery. Organic layer containing MPBAand toluene is taken for hydrolysis in next stage.MPBA in toluene is heated with sulphuric acid (98%) to form MetaphenoxyBenzaldehyde (MPBAD). MEG generated during the reaction is taken forrecovery and recycled. MPBAD + Toluene are fractionally distilled to get pureMPBAD. Toluene and mid fractions recovered during the distillation arerecycled.

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2.5.1 Associated Air PollutantsThe air pollutants identified from the process of manufacturing of Cypermethrinare Chlorine (CIZ), Hydrochloric Acid (HCI) and Sulphur dioxide (SO2).

2.6 DimethoateThe process of manufacturing Dimethoate is furnished below alongwith processchemistry:Step 1: DDP A preparationPhosphorous penta Sulphide reacts with methanol to produce Dimethyl DithioPhosphoric Acid, which is used in next step.

SOCH3P_sP4 CH 2OH_H 2 SSS C H 3Phosphorous pentasulphideimethyl Dithio Phosphoric AcidStep 2: Na-DDPA preparation20% Sodium carbonate is added to the DDPA solution prepared as above till pH7.0. The layers are separated. The toluene layer goes for purification and the

aqueous layer containing sodium salt of DDPA is taken for next step.

SI IOCH3P/

HS CH3I - N a 2 C O 3-- SCH3OIP+CO

CH30'NaD D PAa -DDPA1 6


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Step 3: Methyl monochloro acetate (MMCA)

Monochloro Acetic Acid, Methanol and Catalytic amount of sulphuric acid arerefluxes and MMCA formed is distilled out at 140oC and used for the next step.

C H 2 CICOOH + CH 3 OHH2CICOOCH3 + H2OMonochloroethanolMCAAcetateStep 4: Condensation

N a-DDPA prepared as in step 2 and MMCA prepared as in step 3 are mixed andheated for four hours at 60C under stirring. After the reaction is over same iswashed with water and carried out amidation reaction with MMA at 2 C. Thereaction mass is neutralised to pH 5.5 6.0 with 10% sulphuric acid and theproduct is extracted with ethylene dichloride solvent. The solvent is thenremoved from the separated organic layer under vacuum at 70 -75 C anddimethoate is packed.The process flow diagram is shown in Fig.6.

2.6.1 Associated Air PollutantsThe air pollutants identified from the process of manufacturing of demethoate areHydrogen Sulphide (H2S) and Methanol (CH 3OH). Methanol is not reported bythe industrial units.

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P2S5 --HS to ScurbberMethanolDPATolueneREPARATIONFILTERATIONP2S5ResdueN a 2 C O 3(20%-NEUTRALISATION

S EPER ATI O Nrude Toluene toDistillationM A Met anolMAONDENSATIONPREPARATION S EPER ATI O NNaCI Solution to ETPIceED C%MMAMIDATION10% H 2 SO4

SEPERATION -- Aqueous Layer to ETP

DRYINGDC to RecycleLossFINISHEDDIMETHOATE

Fig. 6: Process Flow Diagram of Dimethoate Manufacturing

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2.7 2,4 Dichlorophenoxy acetic acid (2,4 D)Phenol is chlorinated to get Dichlorophenol, which is condensed with monochloro Acetic Acid in presence of Alkaline solution to get 2,4-D Sodium. Astirrable slurry of 2,4-D Sodium is prepared and its pH adjusted to 1.0 1.2 byadding 98% Sulphuric acid. 2,4-D acid thus formed is filtered, dried & packed.The process flow diagram is shown in Fig. 7.

Q 1CRUBBER ICHLORINATIONHC I. PHENOL2. ACETIC ACIDCONDENSATION

Q 2FILTRATIONII,4-D SODIUM

ACIDIFICATIONOF2,4-D SODIUM

Q31FILTRATION2,4-D ACIDFig. 7: Process Flow Diagram of 2, 4 D Acid Manufacturing

2.7.1 Associated Air PollutantsThe air pollutants identified from the process of manufacturing of 2, 4 D Acidare Hydrochloric Acid (HCI) and Chlorine (C12 ).

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2.8ichlorvos (D.D.V.P)In the first step Tri -Methyl Phosphite (TMP) is slowly allowed to react chemicallywith tri chloro acetaldehyde at controlled conditions of temperature and atambient pressure to produce crude DDVP.Product obtained from step 1 is purified under vacuum by film evaporator to getfinal product having purity around 95%. The chemistry of DDVP manufacturingprocess is stated below: O

C C 1 3 C HO -+- (C H 3 0) 3 P(CI-130)2P -O-CH = CCi z + CH3 C IChloralMPDVPethyl ChlorideThe process flow diagram for manufacture of DDVP is shown in Fig. 8.

Fig. 8: Process Flow Diagram of D.D.V.P. Manufacturing2.8.1 Associated Air Pollutants

Methyl chloride (CH3CI).is identified air pollutant from the manufacturing processof D.D.V.P.

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2.9 EthionPhosphorus penta-sulphide and absolute alcohol are reacted to produce diethyldithiophsophoric acid (DDPA), which is reacted with caustic to form sodium salt ofDDPA. This salt and methylene dibromide are reacted together to produce Ethion. Themanufacturing process step by step is given below alongwith process chemistry:Step 1: Preparation of DithioacidToluene is taken in the reactor and phosphorus pentasulfide is added under stirring.Temperature is raised and ethanol is slowly added under controlled temperatureconditions. During the reaction, hydrogen sulphide gas is evolved. It is absorbed in dilutesodium hydroxide solution in a scrubber.Step 2: Sodium salt preparation:With Dithioacid formed in step No. 1, sodium hydroxide solution is added slowly andtemperature is controlled by circulating cooling water in the jacket of reactor. At the endof reaction, two layers are separated. Aqueous layer is taken for next step and organiclayer is sent for toluene recovery.Step 3: CondensationTo the aqueous solution of sodium salt of dithioacid, methylene bromide is added, andtemperature is raised under maintain condition. At the end of reaction, layers areseparated. Aqueous layer contains sodium bromide and organic layer contain product issteam stripped to remove impurities.

SC 2 H S OI4 C 2H S OH + P 2S 5 -* 2P - SH + H 2 SC 2 H S OSC 2H S OI2HSOI>P-SH+2NaOH-+2P-S-N a +H2OC 2 H S O2HSO

SC2HSOI2HSOIIC2H52P-S-N a +Br-CH2-Br--42P-S-CH2-S-P(2NaBrC 2 H 5 O2HSOC2H521


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The process flow diagram of Ethion manufacturing is given at Fig. 9.CATALYST

Fig. 9: Process Flow Diagram of Ethion Manufacturing

2.9.1 Associated Air Pollutants

Hydrogen Sulphide (H2S) and Ethyl Mercaptan (C2H5SH) are identified airpollutants from the manufacturing process of Ethion.

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2.10 EndosulphanThe manufacturing process for Endosulphan alongwith process chemistry insequence is stated below:Step 1: Hexa-chloro-cyclo-pentadiene (HCCP) is reacted with 2-Butene 1:4-Diol

in presence of carbon tetra chloride as solvent to form Het Diol.CllOH2CC (I +C-'C IICH C C POH2C

But. Diol

C lC lH2OHCI CICI H2OHC lHet Diol

Step: Solid Het Diol is separated from mother liquor by centrifuge.

S tep 3 : Het Diol is then reacted with Thionyl chloride in Carbon tetrachloridesolvent to give Endosulphan solution.

C llC IH2OHlCH2OC CH+ SOC2LcJICI H >S=O+2HCIClCH2OHlCH2OC llStep 4: Carbon tetrachloride is recovered by distillation to give moltenEndosulphan, which is flaked and packedThe process flow diagram of Endosulphan manufacturing is given at Fig. 10.

2.10.1 Associated Air PollutantsHydrochloric Acid (HCI) is identified air pollutant from the manufacturing processof Endosulphan.

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HexachlorocydapentadieneButene Diololvent

Ieactor-IHET Diol Slurrytage-1ecovered SolventCrystallisesvaporationSolventhionyl Chloride Stage-1ecovered HCCPoC Ieactor-IIvaporationTower

DistillationRecovered SolventUnit

Endosulphan (Technical)

Fig. 10: Process Flow Diagram of Endosulphan Manufacturing

2.11 FenvaleratePara chloro toluene (PCT) is chlorinated to Para chloro benzyl chloride (PCBC).The HCI and 012 gases liberated are scrubbed with water and caustic solution.The chlorinated mass is distilled to remove excess PCT. PCBC is reacted withSodium cyanide to form PCCN. The aqueous layer is treated with Sodiumhypoch'orite to reduce cyanide content.The para chloro benzyl cyanide is reacted with Isopropyl bromide in presence ofcaustic to form PLAN. The reaction mass is washed with water. Aqueous layeris taken for NaBr recovery. The organic layer is taken for fractional distillation.PLAN thus obtained is hydrolysed with sulphuric acid to form PCA.PCA is further reacted with Thionyl chloride to obtain PCA chloride. The gasesliberated are scrubbed with water to remove HCl and with caustic to remove SO2.PCA chloride thus obtained is condensed with MPBAD, alongwith sodiumcyanide and washed with water. Organic mass containing solvents is taken forsolvent distillation. Fenvalerate (Tech) thus obtained is packed in drums.

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The aqueous layer containing excess cyanide is treated with Sodiumhypochiorite and is drained to ETP. The process flow diagram is given at Fig.11 A to Fig. 11 EPC TCATALYSTDC MCl,

TO SCRUBBER (30% HCI)

HO L T

C / P C B C + P C T

PC T

CUT

Fig. 11 A. Process Flow Diagram (step PCT to D/PCBC)D/PCBC(96%)N a C NH 2 OCatalyst

Reactor1st. Dilution water1St. Wash Water

Washer(1st. Dilution + 1st. Wash)C N - Effluent(For ON Treatment)

C/PCCN

Fig. 11 B. Process Flow Diagram (step D/PCBC to C/PCCN)

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C /PCCN (96%)IPBr. (98% min.)CatalystCaustic Lye (47%)

Reactor1st. Dilution water1 st . Wash water

WASHER

(1st. DILUTION)Aq. NaBr(For Br, - Recovery)

Effluent to ETP

Ref. IPBr

1st. Fraction

D /PCAN (96%)

DISTILLATION

Residue (Incineration)

Fig. 11 C. Process Flow Diagram (step C /PCCN to D /PCAN)

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D/PCAN (96%)H 2 SO 4 (98%)H 2OED C

1 - HYDROLYSISSpt. H 2 SO 4 (Sell)

PCA +ayerHalf part to StorageTankalf part for IsolationH 2 OCaustic Lye (47%)E DCHexaneHC I2 - ISOLATION

IDCEffluent to ETPPCA + HEXANE

HCI 1 'SOC12S02TS0 2DMF Rec. Hexane

3 - P C A C IReactionDMF Layer

C / P C A C IRec. Hexane1st FractionD / P C A C I

4 - DISTILLATION

Residue (Incineration)

I -^ To Scrubber

Fig. 11 D. Process Flow Diagram (step D/PCAN to D/PCACI)

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N a C NH2OCATALYSTMPBAD (99%)D /PCACI (96%)TOLUENESalt SIn.

1. FEN. REACTION

CN - Effluent (CN - Treatment)

FEN. + TOLUENE

SODA-WASHWATER-WAS

2. WASHINGCN - Effluent (For CN - Treatment)

FEN. + TOLUENE

Rec. TOLUENE

3. CONCENTRATION

FENVALERATE (TECH.)

Fig. 11 E. Process Flow Diagram of Fenvalerate(step D /PCACI to Fenvalerate technical)

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2.11.1 Associated Air PollutantsHydrochloric Acid (HCI), Chlorine (C12) and Sulphur Dioxide (SO2) are identifiedair pollutant from the manufacturing process of Endosulphan.

2.12 MalathionThe process description for manufacturing of Malathion alongwith processchemistry is furnished below:Step 1: DDPA preparationPhosphorus penta sulphide reacts with methanol to produce Dimethyl-Dithio-phosphoric Acid (DDPA).Step 2: DEM preparationMaleic anhydride is reacted with ethyl alcohol in presence of Benzene andcatalytic amount of sulphuric acid. The water formed is removed azeotropicallyand then the solvent is distilled out. The diethyl-maleate (DEM) is neutralised andpurified.Step 3: Malathion preparationIt is manufactured by the condensation reaction (at 70-80 C) of dithio-phophoricacid (DDPA) and diethy-maleate (DEM) in the presence of catalyst. The excessacidity is neutralised using dilute caustic solution and then washed with waterThe solvent and moisture is removed under vacuum and dry Malathion tech ispacked. CH3 0^ SP 2 S5 + 4C H 3 0H>2\\HZSC H 3 0/SHC H C OHCOOC2H5+ 2C2H SOH 6H-- ^ ^H20, 1HSOCH30H000C2H5( D EM )

CH3O / S CHCOOC2H5H3O/ SPQNCH3O NSH C H C O O C 2 H 5H3O 'NSCHCOOC2H5( D E M )H2000C2H5Process flow diagram is shown in Fig. 12.2 9


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DDPA P REPARATIONNaOH + WATER

H ZS GASCRUBBERP 2 S 5DP AMETHANOL -- PREPARATIONTOLUENEPENT NaOH SOLUTIONReaction Mass

FILTERATION I-- PS5 Residue[00'Al

DEM PREPARATION

BENZENEMALEIC ANHYDRIDEETHANOL

SODA SOLUTIONWATER

H2SO4APOUR LOSSESTERIFICATION ETHANOLBENZENEH 2 OCRUDE DEMNEUTRALISATIONLTOETPNEUTRALISED DEM

MALATIIION PREPARATION

DDPA-1------ OEMCONDENSATIONCRUDE MALATHIONCAUSTIC -- - NEUTRALISATION TO ETPWATER

DRYINGL I I-*TOLUENEMALATHION TECHNICAL

Fig. 12: Process Flow Diagram of Malathion manufacturing

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2.12.1 Associated Air PollutantsHydrogen Sulphide (H2S) is an identified air pollutant from the manufacturingprocess of Malathion.

2.13 Methyl Bromide

Methyl Alcohol and Bromine are reacted in a glass lined reactor. After completionof Bromination, distillation of Methyl Bromide is started. As the boiling point ofMethyl Bromide is 4.5 C, chilled brine having temperature less than 8 C iscirculated in the Reflux condenser as well as Product condenser.

Methyl Alcohol + Bromine > Methyl BromideA dense ash (Na2 CO3) column is used to prevent carry over of un-reactedbromine if any. When the colour of the vapour is colourless the reflux condenserchilled brine flow is controlled to allow the vapour to flow to product condenser.The Methyl Bromide vapour gets condensed in the product condenser and flowsto the receiver tank. Chilled brine is circulated in the Jackets of the receivertanks. The process flow diagram for manufacture of Methyl Bromide is shown inFig. 13

Chilled brine inletilled brine inletReflux Producti

Ch illed brine outletondenserondensellhilled brine outletDense ashcolumn

Bromine I Methyl Alcohol

Glasslincd Product Productreactor receiver receiver

with tank tank Container/agitator No. 1 No.2 tonner filling

Fig.13. Process Flow Diagram of Methyl Bromide Manufacturing

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2.13.1 Associated Air PollutantsThere is no reported emission from closed reaction of Methyl Bromidemanufacturing.

2.14. MonocrotophosManufacturing of Monocrotophos, following steps are involved:Step 1: Chlorination of MMAA:Chlorination of Monomethyl acetoacetamide (MMAA), water and methanol aretaken and cooled to 25 C to 30 C temperature then chlorine gas is passed. Afterthe reaction is completed, the reaction mass is neutralised to pH 7.0 with 20%Sodium Carbonate solution. The solvents (methanol & some amount of water)and distilled out and chlorinated product is extracted with EDC. The water isremoved by refluxing the chlorinated product in EDC with simultaneous waterremoval. The reaction mass is taken for the next step.Step 2: CondensationThe chlorinated product (MMACI) is condensed with Trimethyl phosphite (TMP)to form Monocrotophos Technical.The process flow diagram is shown in Fig. 14.

CH3000H2CONHCH3 + 012 -aH3000HCICONHCH3 + HCI(MMAA)M M A C I )CH3OH3 OM M A C I P - OCH3p/C H ? C ICH3OH3O\- C =CH-CO-NHCH 3

C H 3TMPonocrotophos32


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Mathanol + WaterCI FumesMMAAUreaChlorineHLORINATIONSoda Sol" 20%EUTRALISATIONO2 (g)M E T H A N O LDISTILLATION Reuse (16% Water)Recovered Methanol

E DCXTRACTION Aqueous to ETPSOLVENTecovered EDCE D CISTILLATION NaCl + Water to ETPTM PE DC C O N D E N S A T I O N Methyl Chloride

PURIFICATIONMP + EDC + Impurities to EDCRecoveryMONOCROT OPHOSFig. 14: Process Flow Diagram of Monocrotophos Manufacturing


Hydrogen Chloride (HCL) and Methyl Chloride (CH3CI) are identif ied air pollutantfrom the man ufacturing process of Monocrotophos.

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2.15 IsoproturonCumene is nitrated with a mixture of nitric acid and sulphuric acid to producenitrocumenes. Nitrocumenes are reacted with sulphur and caustic soda to givecumidine. Cumidine is reacted with urea and di-methyl amine in presence ofsolvent to produce isoproturon. lsoproturon is isolated by filtration and dried thenpulverised and packed. The process flow diagram is given at Fig. 15NEIXED ACIDNITRATIONPENT ACID FOR SALEWATER. CAUSTIC LYEWASHINGo E T P

Caustic LyeAKE UP MAKE UP WATERWATERS UR SULPHURIC ACIDSULPHUR

REDUCTIONHIOStil PHATFULPHURRECOVERYo ETPDISTILLATIONESIDUES FOR_NCINERATIONOFF GASESWO STAGE-N H 3WATERABSORBERECOVEREDMAKE UP DMAH3 Reuse /Sale4CONDENSATION IIMETHYL AMINEMMONIA/DMARG.LAYER (DMA) RECYCLEDECOVERYPURIFICATION IQUEOUS STREAMWATERAFFINATE to ETPDMUC BRECOVERYECOVERYSEPARATION AQUEOUONOCHLORO RESIDUE ACIDARACUMIDINEBENZENE (MCB)OR REUSE INRECOVERYONDEN-STEP

ORGANICYDROLYSISL A Y E R ORTHO NITROCUMENE FORPURIFICATIONOM STEAM DISTILLATION to ETPNCINERATIONDRYING, PULVERIZING & PACKINGFig 15: Process Flow Diagram of Isoproturon Manufacturing

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2.15.1 Associated Air PollutantsAmmonia (NH3) is an identified air pollutant from the manufacturing process ofIsoproturon.

2.16. PhosaloneOrthoaminophenol is reacted with urea in solvent medium to getbenzoxozolone, which is then chlorinated in solvent medium, and formaldehydeis added to get hydroxy methychloro benzoxazolone (HMCB). HMCB ischlorinated using dry HCI gas to get chloromethyl chlorobenzoxazolone(CMCB) which is extracted in methylene chloride medium. P2S5 is reacted withethyl alcohol to get diethyl dithiophosphoric acid (DDPA) which is neutralisedwith caustic soda to get sodium salt of DDPA. This sodium salt and CMCB arereacted to get crude phosalone.

0NH2 I tNH+ H2 N - C - N H 22N H 3UC=O(HMCB)-NH + HCIC l S/C=00-NH1 C lVC=00-NHN-CH20H+ HCHO

CIS/C=0l^C=OO 0-N-CHz CI+ HC Gas / IH20CIS/C=Ol^/C=0O(CMCB)C2HSOSH

P2S5 + 4C2H SOH-* 2> PH 2 SC2 HSO( DDPA )3 5


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(-HOH-H2ON aPNaOH>fH2OC 2H S Os2 H S Os

(N a salt of DDPA)

C 2 H SO7-SNa Q N CH Z CI -CH2 SC2H5++NaCC2HSOVC=OVC=OSOC2H5

0(Phosalone)

The process flow diagram for manufacture of Phosalone is shown in Fig. 16.

2.16.1 Associated Air PollutantsAmmonia (NH3), Hydrochloric Acid (HCI) and Hydrogen Sulphide (H2S) are theidentified air pollutants from the manufacturing process of Phosalone.

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r -M

L L

C AC 7U2

c G

QUC D= O

G L .

w

ZwJ0U )C CW

Q OUC IDMZ 0

w

UZQOw0

dDwF -zwJO

T ,ZO

w( DL L

Zw0

ZO _IZUw0

UQ

w^2O00s J LW

OwF -ZwJ0U )

U )I -ZwD- JL LL Lw

w02w0JOri

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I0wU!JiQ^NLL

a0Wu0

oZH Z! J QW)OZZ QW---JU )DZZo=UW3QHZwUZOhU )ZZ _IL3wH ZG O _ZZU_0- Q0!-t i j >-0 wZ _OJU


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2.17 PhoratePhosphorus pentasulfide and ethyl alcohol are reacted slowly in the presence ofDiethyl thio phosphoric acid (DETA) heel at 60-65 CHydrogen sulphideevolves from the reaction mixture. The gas is scrubbed with caustic lye. It getsconverted to Di- sodium sulphide and sodium hydrogen sulphide, which has a byproduct value. After the completion of reaction, the product is charged inanother reactor through a sparkler filter. The product of step one is reacted withFormaldehyde and Ethyl Mercaptan at room temperature to produce crudephorate. This is a condensation reaction. Crude Phorate thus obtained fromstep I is washed using washing soda and steam stripped to remove volatileorganics and moisture. The process flow diagram of phorate manufacturingprocess is show in Fig. 17.

SI ISPS - PS(phosphorus pentasulphide)

C 2H 5OSH\ / SH/ +HSC 2 H 5 OSDiethyl thio phosphoric acid( D E T A ) C2H5OH----- Diethyl thio(E thyl A lcohol)hosphoric acid(NaOH Scrubber)__oNHS(Sodium hydrogen sulphide)DETA + 2HCHO2 C2H5SH3(Formaldehyde) (Ethyl Mercaptan)C 2 H S O C H 2 -SC 2 H5CHOs (Phorate)


+ H 2 O

Hydrogen Sulphide (H 2 S) and Ethyl Mercaptan (C2H5SH) are the identified airpollutants from the manufacturing process of Phorate.

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Phosphorous Penta Sulphide

Industrial Alcohol

Ethyl Mercaptan

Para Formaldehyde

DTA Reactor

Caustic lye

Hydrogensuiphide Reactor

F y Product -odium sulphideSoda Ash

Water

Caustic lye

Phorate Reactor

Washing Reactor

Purification Reactor

J Recycle-Irr Phorate-

Water Treatment ReactorChlorine

Organic layer and treatedwater to effluent treatmentplant and incinerator

Fig. 17: Process Flow Diagram of Phorate Manufacturing

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2.18. PhosphamidonDiethylacetoacetamide (DEA) is chlorinated by using chlorine. HCI gasremoved by degassing is scrubbed to obtain HCI as by-product. Reactionmass is neutralised using sodium carbonate and dichloro diethyl acetoacetamide (DDA) present in the organic layer is removed. DDA is diluted insolvent, heated to 100 C and Trimethyl phosphite (TMP) is added. From thereaction mass, methyl chloride gas is removed by degassing andphosphamidon technical is obtained.

The process flow diagram for manufacture of Phosphamidon is shown in Fig.18

0CI OuC H3 -C -CH2 -C - N(C2H5)2 + C12 -H '3 - C - d - C - N(C2H 5 )2 +2HC Idl(DEA)DDA)ChlorobenzeneDDA + (CH3O)3P

(TMP)

H3CO 0H3 0I^I^P-O- C = C - C -N(C2H5)2H3 C0l

(Phorphamidon)

2.18.1 Associated Air PollutantsHydrochloric Acid (HCI) and Methyl Chloride (CH3CI) are the identified airpollutants from the manufacturing process of Phosphamidon

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DE ACHLORINE

CHLORINATION 1 HCI GASW A T E R

S CRUBBE R }TO ETP

DEGASSING

DDA DRYINGMETHYL C HLORIDE

TM PO STAC KaOHTOXIFICATIONSOLVENTPRECONCENTRATIONURIFICATIONE-TOXIFICATION

JET CONDENSATEO E T PHAZARDOUS WASTE TOHOSPHAMIDON TO INCINERATORINCINERATORFig.18: Process Flow Diagram of Phosphamidon Manufacturing2.19inc PhosphideZinc dust is charged in a reactor and heated. Phosphorous is added slowly into the reactor. Once the reaction is completed, Zinc phosphide mass iscrushed in ball mill and packed into desired containers. The process flowdiagram for manufacture of Zinc phosphide is shown in Fig. 192.19.1 Associated Air Pollutants

Phosphorus Pentaoxide (P205 as H3PO4 mist) is identified air pollutants fromthe manufacturing process of Zinc Phosphide.

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ZINC IATER PHOSPHORUSDUSTIANK/RANSFER WATER TO ETPREACTOR

BALL MILLGRINDING

SEIVING

PACKING

DESPATCH

Zinc Phosphide

Fig. 19: Process Flow Diagram of Zinc Phosphide Manufacturing

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3.0 AIR POLLUTANTS FROM PESTICIDE INDUSTRY3.1missions Profile in Pesticide IndustriesIn general, process emissions can be classified into channelised and

fugitive emissions. The channelised emission is a point source emissionfrom process operations and the fugitive emission is an uncontrolledemission from storage tanks/drums, spills, leaks, overflows etc. In order toidentify the various sources of process emissions and their controlsystems in pesticide industries a questionnaire survey and in-depth studyof some pesticide industries were conducted.The manufacturing process for a product is a combination of various unit-operations and unit process. The material balance of the reactants andproducts gives the characteristics and quantity of emissions. However,their quantity is constrained by the efficiency of conversion of the system.Chances of pure process emissions of only one gaseous pollutant arevery less. The process emissions are contaminated by other vapours ofraw materials, solvents and also some times product of the unitoperations. Theoretical emission of pollutants is difficult to compute.Very often during the unit operations wastewater and solid waste areseparated, whereas waste gas is directly released from the reactionsitself. It is observed that no process or production site is directlycomparable to another. However, there are some forms of similarities withrespect to air pollutants with product specific group such asorganochiorine, organophosphate etc.Based on the studies conducted on various pesticide manufacturing units,as the identified pollutants associated with products are given in Table 5.

Table 5: Product and associated priority pollutants

S. No. Pesticide Name of the Pollutants1 . Acephate HC I2. Aluminium phosphide P 205 fumes (as H 3 PO 4 mist)3. Captafol C1 2 and HCI4. Captan C1 2 and HCI5.6 .

CypermethrinDimethoate

C12, HCI and SO2H2 S

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S. No. Pesticide Name of the Pollutants7 . 2, 4 D Acid HCI and C l 28 . Dichlorvos (D.D.V.P) C H 3 C I9 . Ethion H2S and C 2 H 5 SH1 0 . Endosulphan HC I1 1 . Fenvalerate HCI, 01 2 and SO21 2. Isoproturon N H31 3. Malathion H2S1 4. Monocrotophos HCI and CH 3 C I1 5. Phosalone N H3, HCI and H2S1 6 . Phorate H2S and C 2 H 5 SH1 7 .1 8 .

PhosphamidonZinc Phosphide

HCI and CH 3 C IP205 as H 3 PO 4 mist

3.2. SolventsBesides the air pollutant listed in Table 5, the pesticide manufacturingprocesses use various types of solvents for separation of desired productfrom other chemicals. The list of solvents for various pesticidesmanufacturing process is given in Table 6. Spent solvent are recoveredeither recycle in the same system or reuse for other purposes. The un-recovered solvents are generally incinerated in the pesticide industries inIndia. The loss of solvent is not so significant. A well designed LDARprogramme can prevent loss due to fugitive emissions.

Table 6: List of Solvents used in manufacturing process of pesticidesS.

NoName of the

SolventsProduct list

1 . Acetone Quinalphos,cetamiprid,riazophos,Pendimethalin2. Acetonitrile Divenyl acid chloride, Acetamiprid,midachlorprid,Tetrachloroutyronitrile,ypermethrin,A lphamethrin, Permethrin44


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S. Name of the Product listNo. Solvents

Acephate,4-Dacd,_Mancozeb. Acetic acid4. Acetic anhydride Acepate, 2,4-D acid5. Benzene Malathion, Diethyl Aniline, Dimdethoate,Lindane6 . Butanol Aureofungin7 . Carbon Enddsulfan,,6 ,ichloroyridine,ivenylcidtetrachloride chloride,soproturan,etrachloroutyronitrile,Cypermethrin,Alphamethrin, Permethrin8 . Dioxane Metconazole9 . Diethyl Amine Cypermethrin, Alphamethrin, Permethrin, Devrinol1 0 . Di Methyl Fenvalerate,exaconazole,ropiconazole,Formamide Hexaconazole(DMF)11. Ethanol Malathion,horate,thion,erbufos,iethylAniline, Ethylchloride, Phenthoate, Lindane

1 2 Ethyl acetateCaptan, Dimethote, Monocrotophos, Meta Bromo3. Ethylene Di

Chloride Benzaldehyde,envelerate,ypermethrin,PhosphamidonPhorate, Tebufos4 Formaldehyde1 5. Hexane Cypermethrin,lphamethrin,ermethrin,Deltamethrin,envalerate,ypermethrin,ivenylacid chloride, iso proturon1 6 Isopropyl alcohol Delatamethrin, Phosphamidon, lmidactorpnd1 7 . Methanol Dimethote,alathion,ethylromide,hexaconazole,uinalphos,etamitron,Phenthoate, Methyl Paraffnon,Temephos1 8 . Methylene Acephate,ichlorvos,epiquatehloride,Chloride Hexaconazole1 9 . Methylene Acephate, Deltamethrin, Propiconazole

dichloride20 . Piperidine Mepiguate chloride21 . Phenol-D acid, Metanzaidehyde22 , Pyridine D-Allethrin, Carbendazin23 Renine For formulations,-Captafol, Captan, Cypermethrin, Ethion, Malathion,4. Toluene Dimethote,envalerate,-Aminoalicyliccid,Andpa, Meta Phenoxy Denzaldehyde, Permethrin,Benfuresate, d-Allethrin, Penpropathrin, Tenephos,Metconazole25. Triethyl amine Cypermethrin,ivenyl acid chloride,enfuresate,

Permethrin, Deltamethrin26 . Xylene Quinalphos,riazophos,ymoxanil,elalxyl,Marcozeb,nilofos,M T A ,xadiargyl,Benfuresate,Ppphamidon,Pencmethaiin,45


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3.3rioritisation of air pollutants for controlConsidering the health risk or damage to environment and effects on manmade assets and the volume of discharge, a combinatory tree is evolvedfor prioritisation or selection of air pollutant for control, has been identified.This is stated below:

HIGH/

RisLOW

Volume ofDischarge

HIGH Most priority Air pollutant

Medium priority Air pollutantLOW

HIGHess priority Air pollutantVolume ofDischargeLeast priority Air pollutantLOW

An exercise has been made with said combinatorial tree, accordingly thepriority air pollutants identified are listed below:oAmmonia (NH3)oChlorine (Cl2)oHydrogen Bromide (HBr)oHydro Chloric Acid (HCI)oHydrogne Sulphide (H2S)oMethanol (CH3OH)oMethyl Chloride (CH3CI)oPhosphorous Pentoxide (P205 as H3PO4 mist)oSulphur Dioxie (SO2)

3.4. Toxicity and Health Impact of Priority PollutantsSummary of toxic properties of priority pollutants identified from thestudied process are given in Table 7 .

,,


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Table 7: Properties and Health impact of some priority pollutantsS. Pollutants Physical &Chemical Exposure, odour and Health impact

No. Property Corrosively1 . Ammonia Colourless, stable at room TWA 50ppm, Ammoniacal Exposureanause

(NH3 ) temp,nhydrous strong,ighorrosiven coughing,hestainsammoniailleact presence of Cu andts difficultyn

reathing.exothermically withcids alloys.lightlyorrosive Repeatedignificantandater.nhydrous in presence of Al and Zn. overexposureanammonia decompose to Very slightly corrosive in cause permanent lunghydrogennditrogen presencefildteel. functionamage,gasesbove50. Nonorrosiven edemandhemicalDecomposition presenceflassr pneumonitis.aytemperatureaye Stainlessteel304r cause serious damageloweredy contact with 316) to eyescertain metals.2. Chlorine Greenishellowas, TLV.5pm,ungent Can cause itching and(C l 2 ) extremelyeactivean suffocatingleachike burningfhe

yes,reactiolentithany odour,trongly corrosive nose,hroat.tighcombustible materials and toostetalsnhe concentrations chlorineother chemicals including presence of moisture is respiratory poison.water

3. Hydrogen Colourlessas,table TWApm,ungent Toxic-auseseriousBromide incompatibleithtrong suffocatingdour, burns(HBr) oxidisinggents,trong corrosiveoostbases.azardous commonetalsnddecompositionroducts: al loysBromine and H dro en4. Hydro Colourlessolightly TLVTWA 5 ppm, irritating ToxicayeatalfChloric Acid yellowas,table pungentdour,dour inhaled,evere irritant,(HCI) incompatible with alkalis threshold 0.77 ppm, and veryarmfulydryaseousydrogen inhalation,ngestionrchloride can be handled through skin contact.

inanyetalsndalloys,lthoughtelevated temperature thecorrosionates increase.Commonlysedetalsare

arbon

teel

lloy400, 300, series stainlesssteels,lloy00ndNickel 2005, Hydrogne Colourlessas,table, TWA 10 ppm, smell of High toxic may be fatalSulphide highlynflammable,

ay rotten eggs, corrosive to if inhaled. Skin contact(H2S) formxplosiveixture most metals mayauseurns.with air incompatible with Asphyxiant.oxidisinggents,xidesand metals

6 . Sulphur Colourlessas,table, TWAppm,rritating Toxic-highDioxie incompatibleithtrong pungentdour,on concentrations are fatal(SO2) reducingrxidising corrosiveoommon

agents, moisture Zinc and materials except Zn whenits allo s_ y; corrosive when wet

7 . Ethyl Colourlessas,table TWA 0.5ppm, extremely Highly toxic, affects theMercaptan underormaltorage strongndepulsive central nervous system(C2H5SH) condition,ecomposition smell. Odour threshold isofhemicalanmit 0.001 ppmcarbononoxide,hydrogenulphidendsulphur dioxide47


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4.0 AVAILABLE CONTROL TECHNOLOGY TO PREVENT AND CONTROL OFAIR POLLUTANTS FROM PESTICIDE INDUSTRY

4.1rinciple of Air Pollution Control TechnologyPrinciple of air pollution control technology can be broadly classified intofollowing groups.veparation techniques-as solid separationLiquid-liquid separationGas liquid separationvonversation to harmless end producthermal destructionThese are illustrated below.

4.1.1 Separation techniquesIn case of gas solid separation, the following techniques are employed:

SeparatorCycloneMulticloneElectrostatic precipitatorWet dust scrubberFabric filter including ceramic filter

With respect to liquid-gas or liquid-liquid separation, the following techniquesare considered:Mist filterCondensationAdsorptionWet scrubbing

4.1.2 Thermal destructionThermal destruction is generally used, when toxic and carcinogenic chemicalsare emitting from the process. The thermal destruction technology generallyused is stated below:

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Thermal oxidationCatalytic oxidationFlaring

4.1.3 Conversion to harmless product

These techniques are used for organic pollutants; however, these techniquesare not used in India. The techniques are:Bio filtrationBio scrubbingBio trickling

4.1.4 Combination approachThe technique for cleaning of flue gases can combine both recovery andabatement. The techniques are as follows:

Dry sorbent injectionSemi dry sorbent injectionSelective non-catalytic reduction (SNOR) of NOxSelective catalytic reduction (SCR) of NOX

In order to provide an overview, all available techniques are compiled inFig. 20. To this purpose it appears appropriate to distinguish between twosources of waste gases:

"Normal" temperature processes, such as production, handling orwork-up processes, with the main contaminants:-olatile organic compounds such as solventsInorganic gases, such as hydrogen halides, hydrogen sulphide,ammonia, carbon monoxide-articulates in the form of dustIncineration processes, with main contaminants:-articulates in the form of ashes and dust, containing soot,

metal oxides-uel gases such as carbon monoxide, hydrogen halides,

sulphur-oxygen compounds (SOx), nitrogen-oxygen compounds(NOx)

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NCl CCEC0C Q0mQONC0rL-LCNmrNC( 6UEdUE0C Oa >Nc aC )a >NC U

OCc)C Umara )O _0.

OCc)wNN

CL)drd0

N

^ n

COQ )-0 oE u )O O0 0O

OL 0` ~ OC + ^W

EoW .^

iO Or o o ( I )LU 2 2L U - X. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . = O_ Z U2 c aa.O

V/

U )0 0

o) . QO L`ABU O^ _ ON Q3 Ud un OO (6

NC LN dc o O (0 U(0 O O0 C O.n 0CW0CUW++ U (I) o0 2(no:coV C .) 4= y .`-.^a o OUC6La>ao 3.m.in L Q o o O m m o pL0 >,^ m 3'`^Zf ; U ) UQ c00w I =mmco UL i- U cnUwLf-- =n07

@ CU O U UWO 0 )U oc UZO ' c C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ Nc U

V0VC tom CU ) o2cvi Coc o W O o ^ t0 m Cl- _ ^ 2

EO pUW O V U 2C )L L


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Arising waste gases are treated by techniques where:he waste gas content is recovered and either recycled to the originalprocess or used in another process as raw material or energy carrierhe contaminants are abated.Compounds normally worth to recover comprise:

VOC, recovered from, solvent vapours or vapours of low-boilingproductsVOC used as energy carrier in incinerators or boilers

-ydrogen chloride, transferred into hydrochloric acidAmmonia to recycle into the production processyulphur dioxide, transferred into sulphuric acid, sulphur or gypsum-ust containing higher amounts of solid raw products or end products4.2 Control Technologies Adopted in India

On the basis of information received from various industries either inquestionnaire survey or collected during in-depth study of pesticidesindustries, the control technologies adopted to control the identified gaseouspollutants are given in Table 8.

Table 8: Control technologies adopted in Indian industries

S. No Pollutants Control System1 HC I -ater Scrubber,

-austic Scrubber,-ater / C austic Scrubber2 Cl2 -ater Scrubber,-austic Scrubber,-ater / C austic Scrubber3 CH3CI -harcoal Bed Scrubber,_ -iquification, fi ll ing and /or C om bustion4 HS -crubber with N aOC I media-crubber with N aOH m edia_ _ -harcoal Bed Scrubbe r

5 SO 2 -austic Scrubber-ater/Caustic Scrubber

6 P205 -ater Scrubber(as H 3 PO 4) -atercrubberRingetcrubber)istEliminator + Demister-ist Eliminator7 NH3 - Two Stage W ater Scrubber-ecovery System5 1


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4.3

S. No Pollutants Control System8 CH3OH -hannelised E mission was not observed, becausethis chemical (solvent) is used in less quantity inthe ma nufacturing

HBr -austic Scrubber1 0 Odours -ncinerator / chemical reaction

compounds,no nrecoveredsolventsEfficiency Evaluation of Existing Pollution Control TechnologiesThe concept of control efficiency is the limitation of emissions into theatmosphere by the use of air pollution control equipment systems. Theefficiency of pollution control technology / system is defined as the ratio of thequantity of emissions prevented from entering to the atmosphere by thecontrol device to the quantity of emissions that would have entered theatmosphere (quantity input to the control device); if there had been no control.The efficiency of gas cleaning devices is expressed in a variety of ways,including control efficiency, penetration, and decontamination factor. Themost common means for expressing the efficiency of performance is in termsof the control efficiency, which is defined as the ratio of the quantity ofpollutant prevented from entering the atmosphere by the control device to thequantity that would have been emitted (inlet quantity to the gas cleaningdevice) to the atmosphere had there been no control device.

Efficiency (r') = Collected / Inlet = C/I= (Inlet Outlet)/Inlet = (1-0)/I

Penetration is defined as the ratio of the amount of pollutant escaping(penetrating without control) the gas cleaning device to the amount entering.

Penetration (P) = Outlet / InletHence penetration focuses attention upon the quality of the emission stream,but in reality it is actually another way of looking at control efficiency. Since

Efficiency (q) = 1 [outlet / inlet]then= 1 PFor a control efficiency of 99.999% (i.e., E = 0.99999), the penetration is0.00001, or 10 -5 . Alternatively, efficiency can be expressed as thedecontamination factor (DF), which is defined as the ratio of the inlet amountto the outlet amount.

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Decontamination Factor = Inlet / Outlet=1/(1E)For a percentage control efficiency of 99.999%, OF is 105 . The logarithm totl%e base 10 of the decontamination factor is the decontamination index. Inthe numerical example above, this index is 5.0. These efficiency terms areused to represent the overall efficiency of control of a single device or anycombination of control devices.

Based on the data obtained from the industry and also monitored / measuredduring the in-depth study, it is found that the control system as presented inthe Table 9 are suitable for identified priority pollutants on efficiency point ofview.

Table 9: Suitable Control Systems for Priority Pollutants

S. No. Pollutants Control System1 . HC I Water/Caustic Scrubber2. C 1 2 Water/Caustic Scrubber3. CH3CI Liquification system and/or Incinerator4. H2S Scrubber with NaOH media5. S0 2 Water/Caustic Scrubber6 . P205(as H3PO4) Water Scrubber (Ring jet scrubber) + MistEliminator + Demister7 . NH, Two Stage Water Scrubber8 . CftOH Adsorption Bed (Charcoal or Molecular Sieve)9 . H f 3 Y Caustic Scrubber1 0 . Mercaptan Incinerator

After review of available and adopted control technologies for the control ofidentified gaseous pollutants, it is found that the technologies based onabsorption end chemical reaction are being commonly used to control thegaseous pollutants e.g. HC I, H2S, SO2, P205 (as H3PO 4), C1 2, NH 3 and HBr. Incase of H2 S adsorption and incineration technology is also adopted by somepesticide industry. To control the emission of CH3CI, condensation(liquificationmm and incineration system is observed in one or two large scaleindustry.

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4.4 Description of Various Treatment TechniquesIn the previous paragraph, it is indicated that the absorption (scrubber)generally used as air pollution control devices in India for pesticides industry.However, incinerator is also used for destruction of odorous compounds orun-recovered solvents, in some occasion chemical oxidation is also used forabatement of odorous compounds. Condensation is used as an intermediatestep for recovery of chemicals before using cleaning up technology such asincinerator. In this paragraph, an attempt is made to describe the mostcommonly used techniques such as absorption, condensation, chemicalreaction and incinerator as air pollution control devices for controlling prioritypollutants in pesticides manufacturing industries in brief.There are various techniques available for recovery and abatement, however,concerning most important techniques for pesticide manufacturing industriesto control priority (gaseous) pollutants emission are (i) absorption, (ii)adsorption, (iii) condensation, (iv) chemical reaction and (v) incineration.

4.4.1 AbsorptionThe identified priority pollutants from the pesticide process / operation can beefficiently removed using suitable scrubbing liquor in a mass transfer device.The liquor and gas can contact each other while both are flowing in the samedirection (co-current flow), in opposite directions (counter current flow), orwhile are flows perpendicular to the other (cross flow). The scrubbing liquorused for the removal of gaseous pollutants can be by-product, in the form ofslurry or a chemical solution. In chemical engineering terminology thealternate terms for scrubbing is absorption.Absorption is a diffusion-controlled, gas-liquid mass transfer process. Theefficiency of absorption in air pollution control is governed by the ease withwhich contaminants can be transferred through the interface into the liquidface. Absorption is enhanced by high diffusion rates, high solubility, largeinterfacial areas and turbulence. The gaseous containing vapours arescrubbed with water or liquid in which they are soluble. Scrubbing can becarried out in spray columns, packed bed columns, plate columns, floating-bed scrubbers and liquid-jet scrubber or venturi scrubbers. With the properchoice of operating conditions, almost complete removal of gaseous vapour ispossible by this method.

Absorption is carried out in variously designed scrubbers. The variousdesigns of scrubbers are based on the consideration to provide maximumcontact between absorbent and the gas so as to achieve a high efficiency ofgas removal.An account of some common type of scrubbers is given below:

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a) Packet Tower ScrubberThe design of a packed tower scrubber is given in Fig. 21. It consistsof a long tower packed with a suitable inert packing material such aspolyethylene. The absorbent trickles down from the top to downward,while the gases pass in the opposite direction from downward to thetop, thus allowing the maximum reaction time. The presence ofpacking material makes the absorbent to trickle down in thin films toprovide maximum surface area for contact. The packed tower isusually more economic for corrosive gases and vapours in view of thelesser quantities of corrosion resistant materials required for itsconstruction.

b) Plate Tower ScrubberThe construction of a plate tower scrubber is shown in Fig. 22. Itconsists of a long vertical chamber fitted with perforated circular platesat equal spacing. The gases or vapours pass from downward to the topof the tower making a contact with the liquid present on the eachperforated plate. The liquid do not fall through the pores on the platesas it is held by the pressure created by the velocity of the gases. Eachplate is provided with a pipe to carry the excess absorbent downwardfrom plate to plate. The plate towers are most suitable when a frequentcleaning is required particularly in case of the liquid which afterabsorption contains high quantities of particulates and relativelyinsoluble and offensive gases.

c) Spray Tower ScrubberThe design and construction of these scrubbers is given in Fig. 23a toFig. 23c. In these types of scrubbers, the liquid is sprayed on thepollutant gas that provides the turbulence to the gases for betterabsorption. The method is best suited for highly soluble and offensivegases. The design of the scrubber can be so made as to give acentrifugal force to both liquid spray and the gas to achieve maximumcontact between the two for higher efficiency of removal. The spraytower scrubber can also be used for removal of both solid and liquidparticulates.

d) Liquid Jet ScrubberThe device is most suitable for the condensable gaseous pollutants.The scrubber is shown in Fig. 24, and consists of two verticalchambers. In one of the chambers, a liquid jet is sprayed whichatomizes and produces small droplets of the absorbent. Gases arealso introduced into the same chamber from the upper end. Non-condensable clean gases are femoved from the other chamber.

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eon gases

quid distributor

-ramin tower

cking m aterial

cking support plateGas or vapour inlet

Liquid---outlet

e)gitated Tank ScrubberThe effluent gases, in this type of scrubber, are agitated together withthe absorbent in a tank against baffle plates fitted on the sides of thetank as shown in Fig. 25. The turbulence caused by stirring providesgreater absorption efficiency when particulates are also present.

1:....:.i1Fig. 21:- Packed Tower Gas Scrubbe r

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Liquid

Liquid down pip(,

Siel cup

.squid down pip^

, teef cup

CSor vapour

Ciryas

Gus or vapou,

Wei

Sievepinta

'vas or vapour

Neir

Sieve plate

Fig. 22: Plate Tower Gas Scrubber

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C L E A N G A S

DtS1RtBUTVONPLATE

1 1 t S t f 1DIRTY _..-4M A N I F O L DW A T E RP4PINGIRTY GAS CIE. t.'ci,.r{s;j)I ) ! ) 'R E C Y C L EPUMP 5CRU88'N;C L E A N G A S

C O R E B U S T E RD I S K^PRAYM A N I F O L DDIRT Y ^WAIE + R i i W A T E RGASU TN

Fig. 23 (a) to (c) : - Spray Tower Gas Scrubbers

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Liquid spra ylean gasesGasorvapour_.

11

i1

11[1'Wasteefltuent" =L7

Fig. 24: Liquid Jet Scrubber

M O T O

GAS iNld E

-BAFFLEAG) TATOR

I--DRAINFig. 25: Agitated Tank Gas Scrubber

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All these scrubbers described above, operate efficiently at a temperaturebelow 100C that avoids the undue loss of the absorbent by evaporation, andkeeps it in the liquid state. For this, the scrubbers are always preceded bysome cooling devices to bring down the temperature of effluent gases to thedesired level. The treated gases have always a lower temperature, andcontain large quantities of water vapours and absorbent droplets. Demistersor some other suitable devices are installed in sequence after the scrubber toremove water vapours and the traces of the absorbent from the effluentgases. Reheating of the gases is also necessary in most cases to providerequired buoyancy to the gases for their escape from the long stacks.

4.5 Condensation

Condensation is best for vapours with reasonable high vapour pressure. Inthese process volatiles gases and vapours are controlled. Condensation maybe useful for primary recovery before final cleanup with another method suchas adsorption and incineration of gas. In the condensation process gaseswere cooled to achieve adequate condensation. Fog occurs when the rate ofheat transfer appreciably exceeds the rate of mass transfer. When fogformation is unavoidable, it may be removed by high efficiency moist collectordesigned for 0.5-5pg droplets. Condensation procedures were normally usedin the organic-chemical process.

4.6 Chemical ReactionOdours of many organic compounds can be destroyed by strong oxidantssuch as KMnO4 , HNO3, H 2 02 , K2Cr2O7 and hypochlorite solution. Conversionof HCI to NH 4CI is an example of changing a gas to a particulate (as by-product). Use of alkaline scrubbing medium to collect acidic gases is a wayof enhancing the collection of an absorption process. In general, gaseouspollutants were collected easily by chemical reactions.

4.7ncineration Technology with Air Pollution Control DeviceIncinerator is a versatile process. Organic materials are destroyed the organicmolecular structure by oxidation or thermal degradation. Incineration providesthe highest degree of destruction and control for a broad range of hazardoussubstances. Design and operating experience exists and a wide variety ofcommercial incineration system are available, which are stated below:

( i) Liquid injection;(ii) Rotary kiln;(iii) Fixed hearth;(iv) Fluidised bed incinerator; and(v)yrolysis bases incinerationo m


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In India, it is observed that selection of incinerator technology mainly guidedby physical state of hazardous waste generated by the pesticides industry.The incinerator technology adopted by pesticides industries is given in Table1 0,Table 10: Incinerator Technology adopted by Pesticides Industries

Physical state T e^ % share Technology adoptedOnly liquid waste Only aqueous 1 0 0 Liquid injection

(horizontal)Aqueous 9 0 Fluidised bed+ combustionLiquid organic 8Aqueous 40-50 Liquid injectionLiquid organic 40-50

Predominantly Liquid 70-95 Liquid injectionliquid with some +solid waste Soid 5- 30 PyrolysisOnly solid waste Solid waste 1 0 0 Rotary kiln(solid & semisolid) - -Typical air pollution control devices for controlling different pollutants from anincinerator are given in Table 11.

Table 11:ir Pollution Control Devices for Controlling DifferentPollutantsAir pollutant Air pollution control devices (APCDs)Acidases,ercury,ioxin, Packedowers,prayryersrryand Furan Emission injectionactivatedarbon,ime)scrubbers_______Particulatendeavyetal Venturicrubbers,etrryEmission electrostaticrecipitatorsES P s )rfab ric filtersOxide of Nitrogen Emission Selective non-catalytic reduction (SNCR)a nd selective catalytic reduction (SC R)__

4.8 AdsorptionBesides the techniques stated above on air pollution control system ofpesticide, adsorption technique has a large potential too. Adsorption is asurface phenomenon by which gas or liquid molecules are captured by andadhere to the surface of the solid adsorbent. It is desirable for removal of

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contaminant gases to extremely low levels (


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5.0 AN APPROACH FOR DEVELOPMENT OF EMISSION STANDARDS FORPESTICIDE INDUSTRY

5.1ntroductionThe National Environment Policy (NEP), 2006, with respect to emissionstandards i.e. permissible discharges of specified waste by different class ofactivities relates to risk reduction of health, sensitive and valuable ecosystem andmanmade asset. The NEP further stated that standard for each class of activitiesneed to be set on the basis of general availability of required technology, thefeasibility of achieving the applicable environmental quality standards at thelocation (specific or category) concerned with the proposed emissions standards,and the likely unit costs of meeting the proposed standard. It is also importantthat the standard is specified in terms of quantities of pollutants that may beemitted,

Documents

Development of National Emission Standards for Pesticides Manufacturing Industry