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    Pesticide Industry Pesticide Industry Document Transcript

    • PESTICIDE INDUSTRY Page 2 INDEX – Sr no. Description Page No 1 Introduction 2 2 Manufacturing process 6 3 Water consumption& waste generated 12 4 Waste characteristics 13 5 Effluent standards 14 6 Pollution effects 16 7 Volume & strength reduction 20 8 Recovery techniques 21 9 Effluent treatment 22 10 References 30
    • PESTICIDE INDUSTRY Page 3  INTRODUCTION- Pesticides are defined as the substance or mixture of substances used to prevent, destroy, repel, attract, sterilise, mitigate any insects. Generally pesticides are used in three sectors viz. agriculture, public health and consumer use. The consumption of pesticide in India is about 600 gms / hectare, where as that of developed countries is touching 3000 gms / hectare. There are about 150 industrial units manufacturing pesticides (technical) and About 500 industrial units engaged in formulations in the country. There is a wide range of pesticides found used in non-agriculture situations such as industries, public health and for a number of purposes in the home. Domestic use of pesticides is mainly as fly killer, ant killer, repellants, rodenticides and fungicides etc. By and large industrial use of pesticide is of vital importance in the industries such as wood and carpet, wood preservation etc. Pesticide commonly used in the agriculture can be grouped as-  Insecticides – It control the insects that damage the crops. The classes are chlorinated hydrocarbons, organophosphates, carbamates. They are used on lawns, vegetables, grapes, tobacco, forest trees etc.  Organic fungicides and bactericides- They control plant molds & other diseases. Their classes are dicarboximides,dithiocarbamates,synthetic fungicides. Fungicides protects plants from fungal growth. They are used on grain, vegetables, grapes etc.  Organic herbicides- Herbicides are used to control the weeds which compete with crop plants with water, nutrients, space & sunlight. Their classes are phenoxyaliphathic acid,nitroanilines,aryaliphatic acid. They used on the grapes, fruit trees, sugar beets, beans, rice etc.  Pesticide Production in India- India is the largest producer of pesticides in Asia and ranks twelfth in the world for the use of pesticides. Pesticide is manufactured as technical grade products and consumable pesticides are then formulated .The installed capacity of technical grade
    • PESTICIDE INDUSTRY Page 4 pesticide was 1,45,800 tonnes during March 2005, and the production in the financial year 2004-05 was 94,000 tonnes. Year Production tonnes/ year 2001-02 81800 2002-03 69600 2003-04 84800 2004-05 94000  Comparison of pesticide use in India and worldwide-  Uses of pesticides in India – Sector Use Agriculture For control of pests, weeds, rodents, etc. Public health For control of malaria, dengue fever, cholera. Other than agriculture & public health Control of vegetation in forests and factory sites, fumigation of buildings and ships Domestic Household and garden spray, control of animals and birds Personal For application of clothing & skin care
    • PESTICIDE INDUSTRY Page 5 Material building Incorporation of paints, glues, plastic protection, sheeting, foundation of buildings etc.  State wise production in India during the year 2005/06 – State Production in MT/year Gujarat 36.05 Maharashtra 32.16 Andhra Pradesh 2.665 Kerala 2.407 Karnataka 0.11  Major pesticide control legislation in India- Legislation Regulatory body Insecticide Act, 1968 and the Insecticides Rules, 1971 Ministry of Agriculture Department of Agriculture & Cooperation Environment Protection Act, 1986 Ministry of Environment & Forest Prevention of Food Adulteration Act, 1954 Ministry of Health & Family Welfare  Persistence in soil of some pesticides- Insecticides, Herbicides and their groups Persistence Organophosphates 7-84 days DDT 10 yrs Carbamate 2-8 weeks Aliphathic acid 3-10 weeks Diuron 16 Months BHC 11 yrs Toxaphene 6 yrs
    • PESTICIDE INDUSTRY Page 6  MANUFACTURING PROCESS- Technical grade pesticide
    • PESTICIDE INDUSTRY Page 7  Formulating industry-
    • PESTICIDE INDUSTRY Page 8 PROCESS DESCRIPTION- The pesticide are produced in two stages the manufacture of pesticide and the formulation of the final product. Most of the pesticide pesticide process are batch process, the remaining are continous processes.  Raw material- The raw material used in the production of pesticide might include a large number of organic or inorganic compounds. There are various types of raw material or chemicals used for the different pesticide manufacturing such as herbicide, insecticide, fungicides etc. For ex. In the manufacturing process of malathion the raw materials used are DDPA (dimethyl-dithio phosphoric acid) and DEM (diethyl maleate). For DDT chlorine &ethanol, chlorobenzene are use as a raw materials.  Reactor system- In this reactor system the chemical reactions, chemical process is takes place in the presence of chemicals. There are various types of unit processes such as oxidation, nitration, condensation etc.  Fractionation system- Fractionation is a separation process in which a certain quantity of a mixture (solid, liquid, solute, suspension or isotope) is divided up in a number of smaller quantities (fractions) in which the composition changes. The recovery of certain chemicals can be done in this process.  Dryer- Drying is a mass transfer process consisting of the removal of water or another solvent by evaporation from a solid, semi-solid or liquid. This process is often used as a final production step before selling or packaging products.  Scrubbers- The identified priority pollutants from the pesticide process / operation can be efficiently removed using suitable scrubbing liquor in a mass transfer device. The liquor and gas can contact each other while both are flowing in the same direction (co-current flow), in opposite directions (counter current flow), or while are flows perpendicular to the other (cross flow). The scrubbing liquor used for the removal of gaseous pollutants can be by-product, in the form of
    • PESTICIDE INDUSTRY Page 9 slurry or a chemical solution. Scrubbing can be carried out in spray columns, packed bed columns, plate columns, floating bed scrubbers and liquid-jet scrubber or venturi scrubbers. The wastewater generated from the scrubbing action is further goes to wastewater treatment plant.  Packaging- The technical grade pesticide shall be packed in dry and clean containers. There are various types of drums are used for packaging of pesticides. The types are depend on the pesticide which is packed. The mild steel drums, HDPE drums, aluminium clad containers are used for liquid pesticide packaging. The packing drums are used are capacity of 10, 25, 50,100,200 lits. The drum should be temperproof. The closer should be provided so for not allowing leaking the drum. The drums should be sturdy.  Formulating unit/ industry - After a pesticide is manufactured in its relatively pure form (the technical grade material) the next step is formulation – processing a pesticide compound into liquids, granules, dusts, and powders to improve its properties of storage, handling, application, effectiveness, or safety. The technical grade material may be formulated by its manufacturer or sold to a formulator/ packager. The most important unit operations involved in formulation are dry mixing and grinding of solids, dissolving solids, and blending. Formulation systems are virtually all batch-mixing operations.  Active ingredient- These are the active ingredient which is the technical form of pesticide.  Mill- In this unit the grinding of pesticides is done. Some of the pesticides are in solid state which can cause problem in the mixing with the solvents in mixing tank. So for proper mixing the grinding is done before it.  Mixing tank- Liquid formulating- Liquid formulations contain mixtures of several raw materials, including pesticide active ingredients, inert ingredients, and a base solvent, and may also contain emulsifiers or surfactants. The solvent may be water or an organic
    • PESTICIDE INDUSTRY Page 10 chemical, such as isopropyl alcohol or petroleum distillate. In some cases, the formulation is an emulsion and contains both water and an organic solvent. Solid materials, such as powders or granules, may also be used as part of a liquid formulation by being dissolved or emulsified in the solvent to form a liquid or suspension. The formulated product may be in a concentrated form requiring dilution before application, or may be ready to apply. Typical liquid formulating lines consist of storage tanks or containers to hold active and inert raw materials, and a mixing tank for formulating the pesticide product. A storage tank may also be used on the formulating line to hold the formulated pesticide product, prior to a packaging step. These raw materials are either piped to the formulation vessel from bulk storage tanks, or added directly to the vessel from drums, bags. Typically, water or the base solvent is added to the formulation vessel in bulk quantities. The formulating line may also include piping and pumps for moving the raw material from the storage tanks to the mixing tank, and for moving formulated pesticide product to the packaging line. Other items that may be part of the line are premixing tanks, stirrers, heaters, bottle washers, and air pollution control equipment. Some lines may also contain refrigeration units for formulation, storage units and other equipment. Dry formulation- Dry formulations contain active and inert ingredients; the final product may be in many different forms, such as powders, dusts, granules, blocks, solid objects impregnated with pesticide, pesticides formed into a solid shape or microencapsulated dusts or granules. They are formulated in various ways, including mixing powdered or granular actives with dry inert carriers, spraying or mixing a liquid active ingredient onto a dry carrier, soaking or using pressure and heat to force active ingredients into a solid matrix, mixing active ingredients with a monomer and allowing the mixture to polymerize into a solid, and drying or hardening an active ingredient solution into a solid form. These dry pesticide products may be designed for application in solid form or to be dissolved or emulsified in water or solvent prior to application. Dry formulating lines typically have tanks or containers to hold the active ingredients and inert raw materials, and may include mixing tanks, ribbon blenders, extruding equipment, high-pressure and temperature tanks for impregnating solids with active ingredient.
    • PESTICIDE INDUSTRY Page 11 Raw materials for dry pesticide products may be liquid or solid. Liquid raw materials may be stored in drums, or bottles. Dry raw materials may be stored in silos, metal drums, fiber drums, bags, or boxes. Liquid raw materials may be pumped, poured, or sprayed into formulation vessels, while dry raw materials are frequently transferred to formulation equipment by screw conveyors (consisting of a helix mounted on a shaft and turning in a trough), through elevators, or by pouring.  Packaging- Liquid packaging- Many liquid formulations are packaged by simply transferring the final product into containers. Small quantities of product are often manually packaged by gravity feeding the product directly from the formulation tank into the product container. For larger quantities, the process is often automated. Formulated product is transferred to the packaging line through pipes or hoses, or is received from a separate formulating facility, and placed in a filler tank. A conveyor belt is used to carry product containers, such as jugs, bottles, cans, or drums, through the filling unit, where nozzles dispense the appropriate volume of product. The belt then carries the containers to a capper, which may be automated or manual, and then to a labeling unit. Finally, the containers are packed into shipping cases. Dry packaging- Dry formulations are also packaged by simply transferring the final product into boxes, drums, jugs, or bags. Again, small quantities or bags are typically packaged manually using a gravity feed to carry the product from the formulating unit into the containers or bags. Larger quantities may be packaged on an automated line, similar to liquid packaging lines.
    • PESTICIDE INDUSTRY Page 12  Water consumption & waste generation-  Wastewater generated from pesticides manufacturing processes consists of reaction water from chemical processes, process solvent water, process stream wash water, product wash water, spent acid etc.  Because of the nature of pesticides and their components, wastewaters generated from manufacturing plants usually contain toxic. The pollutants or groups of pollutants likely to be present in raw wastewater include halomethanes, cyanides, haloethers, phenols, heavy metals ,pesticides etc.  Washing and cleaning operations provide the principal sources of wastewater in formulating and packaging operations. Because these primary sources are associated with cleanup of spills, leaks, area wash downs, and storm water runoff.  Wastewaters from formulation and packaging operations typically have low levels of BOD, COD and TSS, and pH is generally neutral.  Also use of wet scrubber contributes to the waste water generation.  Waste water contributes from packaging of technical grade pesticides. Waste generation- Manufacture plant Kg/ton of active ingredient manufacture 200 Formulation plant Kg/ton of formulated product 3-4
    • PESTICIDE INDUSTRY Page 13  Characteristics of Pesticide waste – DITHANE Parameter (mg/l) pH 6.9 Total Solids 33000 Suspended solids 2000 Dissolved solids 31000 Total volatile solids 3220 BOD5 180 COD 1372 Chlorides 1500 Sulphates 2050 Manganese 215 Zinc 4
    • PESTICIDE INDUSTRY Page 14  Central pollution control board Effluent standards for Pesticide industry - Parameter Standards Temperature Shall not exceed 5 deg. above the receiving water temp. pH 6.5-8.5 Oil & grease 10 BOD 3 days 27° C Technical unit 100 BOD 3 days 27°C Formulation unit 30 Total suspended solids 100 Bio assay test 90% survival of fish after 96 hrs in 100% effluent Specific Pesticides In mg/l DDT 0.01 Benzenl Hexachloride 0.01 Endosulfan 0.01 Carbonyl 0.01 Malathion 0.01 Fenitrothion 0.01 Diamethoate 0.45 Phorate 0.01 Sulphar 0.03 2,4 D 0.4 Methyl parathion 0.01 Phenathoate 0.01 Pyrethrums 0.01 Ziram 1 Paraquate 2.3 Proponil 7.3 Copper sulphate 0.05 Copper oxychloride 9.6 Other pesticides 0.10
    • PESTICIDE INDUSTRY Page 15 Heavy Metals In mg/l Copper 1 Managanese 1 Zinc 1 Mercury 0.01 Antimony as sb 0.1 Any other metal like Nickel etc Shall not exceed 5 times the Drinking water standards of BIS Organics In mg/l Phenol & Phenolic compounds as C6H5OH 1 Inorganics In mg/l Arsenics as As 0.2 Cyanide as CN 0.2 Nitrate as NO3 50 Phosphate as P 5 Emissions In mg/Nm3 HCL 20 Cl 2 5 H2S 5 P2O5 as H3PO4 10 HBr 5 NH3 30 Particulate matter with pesticide compounds CH3Cl 20 HBr 5
    • PESTICIDE INDUSTRY Page 16  Pollution Effects -  Effects on Streams –  Presence of suspended solids causes odor & lowers the DO level in stream which is deadly to aquatics. It also increases the turbidity of water course & enhances flooding by diminishing the stream bed volume.  High BOD values will increase the organic matters & create unpleasant tastes, odors & general septic conditions due oxidation of organic matters. It decreases DO level & affects deadly to aquatic life.  All salts, some even in low concentration, are toxic to certain forms of aquatic life. chlorides are toxic to fish in 400ppm.  Effects on Sewers –  Suspended solids may cause clogging of sewers by getting accumulated at an invert.  The waste contains sulphates which are converted into H2S gas which can form odour problem.  The presence of sulphates also forms crown corrosion.  Effects on STPs –  BOD exerted by organics imposes a load on treatment plant. Increase in BOD load requires greater biological unit capacity for its treatment which increases daily operating expenses.  Suspended solids from industrial waste sometime may settle more rapidly than that of sewage solids, which are necessary to be removed at shorter intervals, otherwise they will build up excessively at tank bottom & cause septic conditions. Slower settling of industrial solids will require longer detention period & larger basins which increases the unit cost.
    • PESTICIDE INDUSTRY Page 17  Effects of Pesticide on Ecology-  Water- Pesticides are found to pollute every source of water including wells. The main routes through which pesticides reach the water are: 1. It may drift outside of the intended area when it is sprayed. 2. It may percolate, or leach, through the soil. 3. It may be carried to the water as runoff. 4. It may be spilled accidentally. They may also be carried to water by eroding soil.  Soil- Many of the chemicals used in pesticides are persistent soil contaminants whose impact may endure for decades and adversely affect soil conservation. The use of pesticides decreases the general biodiversity in the soil.  Air- Pesticides can contribute to air pollution. Pesticide drift occurs when pesticides suspended in the air as particles are carried by wind to other areas, potentially contaminating them. Volatile pesticides applied to crops will volatilize and are blown by winds to nearby areas posing a threat to wildlife. Sprayed pesticides or particles from pesticides applied as dusts may travel on the wind to other areas, or pesticides may adhere to particles that blow in the wind, such as dust particles.  Effects on human- Pesticides may cause acute and delayed health effects in those who are exposed. Pesticide exposure can cause a variety of adverse health effects. These effects can range from simple irritation of the skin and eyes to more severe effects such as affecting the nervous system, mimicking hormones causing reproductive problems, and also causing cancer. Strong evidence also exists for other negative outcomes from pesticide exposure including neurological, birth defects, fetal death, and neurodevelopment disorder.
    • PESTICIDE INDUSTRY Page 18  Effects on Biota-  Plants- Nitrogen fixation, which is required for the growth of higher plants, is hindered by pesticides in soil. The insecticides DDT, methyl parathion, and especially pentachlorophenol have been shown to this effect. It results in reduced nitrogen fixation and thus reduces crop yields.  Animals- Pesticides inflict extremely widespread damage to biota, and many countries have acted to discourage pesticide usage through their Biodiversity Action Plans. Animals may be poisoned by pesticide residues that remain on food after spraying, for example when wild animals enter sprayed fields or nearby areas shortly after spraying. Widespread application of pesticides can eliminate food sources that certain types of animals need, causing the animals to relocate, change their diet. Poisoning from pesticides can travel up the food chain. It affects on reproductive system of animals.  Aquatic life- A major environmental impact has been the widespread mortality of fish and marine invertebrates due to the contamination of aquatic systems by pesticides. This has resulted from the agricultural contamination of waterways through fallout, drainage, or runoff erosion, and from the discharge of industrial effluents containing pesticides into waterways. Most of the fish in Europe's Rhine River were killed by the discharge of pesticides, and at one time fish populations in the Great Lakes became very low due to pesticide contamination. Pesticide surface runoff into rivers and streams can be highly lethal to aquatic life, sometimes killing all the fish in a particular stream. Application of herbicides to bodies of water can cause fish kills when the dead plants rot and use up the water's oxygen, suffocating the fish. Some herbicides, such as copper sulfite, that are applied to water to kill plants are toxic to fish and other water animals at concentrations similar to those used to kill the plants. Some pesticides can cause physiological and behavioural changes in fish that reduce. Insecticides are more toxic to aquatic life than herbicides and fungicides.
    • PESTICIDE INDUSTRY Page 19  Birds- Pesticides had created striking effects on birds, those in the higher trophic levels of food chains. Pesticides will also kill grainand plant-feeding birds, and the elimination of many rare species of ducks and geese. Populations of insect eating birds such as partridges, grouse, and pheasants have decreased due to the loss of their insect food in agricultural fields through the use of insecticides.
    • PESTICIDE INDUSTRY Page 20 Volume & Strength reduction-  Waste segregation is an important step in waste reduction. Process wastewater containing specific pollutants can often be isolated and disposed of or treated separately.  Wastewater generation can be reduced by general good housekeeping procedures such as substituting dry cleanup methods for water wash downs of equipment and floors. This is especially applicable for situations where liquid or solid materials have been spilled.  Flow measuring devices and pH sensors with automatic alarms to detect process upsets are two of many ways to effect reductions in water use.  Prompt repair and replacement of faulty equipment can also reduce wastewater losses.  Floor wash water, surface runoff, scrubber effluents, water can be reused.  Use wet clothes instead of direct water application for floor wash. Use proper chemicals instead of water to remove colours on floors.  Use of automated filling systems for reactors, tanks and drums to minimize spills.  Use of low-volume, high efficiency cleaning systems (e.g. high pressure spray nozzles and steam cleaners).  Periodic cleaning of lines, using a plastic or foam “pig”.  Liquid pesticide packs should not be overfilled, and filling equipment should be designed to avoid splashing / foaming.  Proper and adequate training for the workers & awareness about environment.
    • PESTICIDE INDUSTRY Page 21  Recovery techniques- There are various techniques available for recovery however, concerning most important techniques for pesticide manufacturing industries to control priority pollutants emission are (i) absorption, (ii) adsorption, (iii) condensation, (iv) chemical reaction and (v) incineration (vi)Reverse osmosis & Ultrafiltration.  Absorption- The identified priority pollutants from the pesticide process / operation can be efficiently removed using suitable scrubbing liquor in a mass transfer device. The liquor and gas can contact each other while both are flowing in the same direction (co-current flow), in opposite directions (counter current flow), or while are flows perpendicular to the other (cross flow). The scrubbing liquor used for the removal of gaseous pollutants can be by-product, in the form of slurry or a chemical solution. Scrubbing can be carried out in spray columns, packed bed columns, plate columns, floatingbed scrubbers and liquid-jet scrubber or venturi scrubbers.  Adsorption- Adsorption is a surface phenomenon by which gas or liquid molecules are captured by and adhere to the surface of the solid adsorbent. It is desirable for removal of contaminant gases to extremely low levels and handling large volume of gases with quite dilute contaminants.
    • PESTICIDE INDUSTRY Page 22 Source control of pesticide waste - Source control and waste minimization can be extremely effective in reducing the costs for in plant controls and end-of-pipe treatment, and in some cases can eliminate the need for some treatment units entirely. The first step is to prepare an inventory of the waste sources and continuously monitor those sources for flow rates and contaminants. The next step is to develop in-plant operating and equipment changes to reduce the amount of wastes. The following are some of the techniques available for the pesticides manufacturing facilities. Waste segregation is an important step in waste reduction. Process wastewaters containing specific pollutants can often be isolated and disposed of or treated separately in a more technically efficient and economical manner. Highly acidic and caustic wastewaters are usually more effectively adjusted for pH prior to being mixed with other wastes. Separate equalization for streams of highly variable characteristics is used by many plants to improve overall treatment efficiency. Wastewater generation can be reduced by general good housekeeping procedures such as substituting dry cleanup methods for water washdowns of equipment and floors. This is especially applicable for situations where liquid or solid materials have been spilled. Flow measuring devices and pH sensors with automatic alarms to detect process upsets are two of many ways to effect reductions in water use. Prompt repair and replacement of faulty equipment can also reduce wastewater losses. Reactor and floor washwater, surface runoff, scrubber effluents, and vacuum seal water can be reused. Treatment methods of pesticide waste -  Activated carbon adsorption treatment  Hydrolysis  Chemical oxidation  Resin adsorption
    • PESTICIDE INDUSTRY Page 23  Activated carbon adsorption- Activated carbon adsorption is a well-established process for adsorption of organics in wastewater, water, and air streams. Granular activated carbon (GAC) packed in a filter bed or of powdered activated carbon (PAC) added to clarifiers or aeration basins is used for wastewater treatment. In the pesticide industry, GAC is much more widely used than PAC. Figure shows the process flow diagram of a GAC system with two columns in series, which is common in the pesticide industry. Activated carbon studies on widely used herbicides and pesticides have shown that it is successful in reducing the concentration of these toxic compounds to very low levels in wastewater. Some examples of these include BHC, DDT, 2,4-D, toxaphene, dieldrin, aldrin, chlordane, malathion, and parathion. Adsorption is affected by many factors, including molecular size of the adsorbate, solubility of the adsorbate, and pore structure of the carbon. A summary of the characteristics of activated carbon treatment that apply to the pesticide industry follows. 1. Increasing molecular weight is conducive to better adsorption. 2. The degree of adsorption increases as adsorbate solubility decreases. 3. Aromatic compounds tend to be more readily absorbed than aliphatics. 4. Adsorption is pH-dependent; dissolved organics are generally adsorbed more readily at a pH that imparts the least polarity to the molecule. Activated carbon adsorption is mainly a waste concentration method. The exhausted carbon must be regenerated or disposed of as hazardous waste. Thermal regeneration is the most common method for GAC reactivation, although other methods such as washing the exhausted GAC with acid, alkaline, solvent, or steam are sometimes practiced for specific applications. Other adsorbing materials besides GAC have also been investigated for treating pesticide containing wastewaters such as pine bark, a wood charcoal.
    • PESTICIDE INDUSTRY Page 24  Resin adsorption- Adsorption by synthetic polymeric resins is an effective means for removing and recovering specific chemical compounds from wastewater. The operation is similar to that of GAC adsorption. Polymeric adsorption can remove phenols, amines, caprolactam, benzene, chlorobenzenes, and chlorinated pesticides . The adsorption capacity depends on the type and concentration of specific organics in the wastewater as well as pH, temperature, viscosity, polarity, surface tension, and background concentration of other organics and salts. Regeneration can be conducted with caustic or formaldehyde or in solvents such as methanol, isopropanol, and acetone. Batch distillation of regenerant solutions can be used to separate and return products to the process. In study regarding the treatment of effluent from a manufacturer of chlorinated pesticides with Amberlite XAD- 4 and GAC. Results indicated that the leakage of unadsorbed pesticides from the XAD-4 column was significantly lower than that from the GAC column. An economic analysis indicated that pesticide waste treatment via XAD-4 resin and chemical regeneration would be more economical than GAC adsorption using external thermal regeneration.  Chemical oxidation- Chemical oxidation modifies the structure of pollutants in wastewater to similar, but less harmful, compounds through the addition of an oxidizing agent. During chemical oxidation, one or more electrons transfer from the oxidant to the targeted pollutant, causing its destruction. One common method of chemical oxidation, referred to as alkaline chlorination, uses chlorine (usually in the form of sodium hypochlorite) under alkaline conditions to destroy pollutants such as cyanide and some pesticide active
    • PESTICIDE INDUSTRY Page 25 ingredients. However, facilities treating wastewater using alkaline chlorination should be aware that the chemical oxidation reaction may generate toxic chlorinated organic compounds, including chloroform, bromodichloromethane, and dibromochloromethane, as byproducts. Adjustments to the design and operating parameters may alleviate this problem, or an additional treatment step (e.g., steam stripping, air stripping, or activated carbon adsorption) may be required to remove these byproducts. Chemical oxidation can also be performed with other oxidants (e.g., hydrogen peroxide, ozone, and potassium permanganate) or with the use of ultraviolet light.Although these other methods of chemical oxidation can effectively treat pesticide wastewaters.  Hydrolysis- Hydrolysis is a chemical reaction in which organic constituents react with water and break into smaller (and less toxic) compounds. Basically, hydrolysis is a destructive technology in which the original molecule forms two or more new molecules. In some cases, the reaction continues and other products are formed. Because some pesticide active ingredients react through this mechanism, hydrolysis can be an effective treatment technology for pesticide wastewater. The primary design parameter considered for hydrolysis is the half-life, which is the time required to react 50% of the original compound. The half-life of a reaction generally depends on the reaction pH and temperature and the reactant molecule (e.g., the pesticide active ingredient). Hydrolysis reactions can be catalyzed at low pH, high pH, or both, depending on the reactant molecule. In general, increasing the temperature increases the rate of hydrolysis.
    • PESTICIDE INDUSTRY Page 26  Disposal of pesticide Wastes – 1) Incineration 2) Deep well disposal 3) Ocean disposal  Incineration - Incineration is an established process for virtually complete destruction of organic compounds. It can oxidize solid, liquid, or gaseous combustible wastes to carbon dioxide, water, and ash. In the pesticide industry, thermal incinerators are used to destroy wastes containing compounds such as hydrocarbons (e.g., toluene), chlorinated hydrocarbons (e.g., carbon tetrachloride), sulfonated solvents (e.g., carbon disulfide), and pesticides. More than 99.9% pesticide removal, as well as more than 95% BOD, COD, and TOC removal, can be achieved if sufficient temperature, time, and turbulence are used. Sulfur- and nitrogen-containing compounds will produce their corresponding oxides and should not be incinerated without considering their effects on air quality. Halogenated hydrocarbons not only may affect air quality but also may corrode the incinerator. Also, organometallic compounds containing cadmium, mercury, and so on, are not recommended for incineration because of the potential for air and solid waste contamination. Using the proper type of incinerator and operating conditions to destroy the pesticide wastes, the incineration system must be equipped with the proper emission controls to ensure that toxic gases and particulates do not escape into the environment. The ash (which may contain hazardous substances) must be properly disposed. Many wet collection systems (scrubbers) can be used for removing gaseous pollutants. The various types of scrubbers available include venturi, plate, packed tower, fiber bed, spray tower, centrifugal, moving bed, wet cyclone, self-induced spray, and jet. Dry collection equipment is available for the removal of particulate pollutants and includes settling chambers, baffle chambers, skimming chambers, dry cyclones, impingement collectors, electrostatic precipitators, and fabric filters. The incinerator ash, scrubber water, and particulate collection can then be landfilled, chemically treated, or otherwise processed for disposal. Incinerator type Temp °C Fluidized bed 982 Fume 1664 Cyclonic 1664 Rotary kiln 815
    • PESTICIDE INDUSTRY Page 27 Effluent Treatment Flow Chart – Pumping Discharge Fenton oxidation Settling tank Activated carbon treatment Equali sation Equali sation Extended Aeration SST Treated eff. sump
    • PESTICIDE INDUSTRY Page 28 The Indofill chemicals Ltd. Have a large scale plant for the manufacture of pesticide located at Thane is selected for making ETP. The company manufactures Dithane which is one type of pesticide. The plant works in 3 shifts for all 7 day in a week. The industry discharges about 44 thousand litrs of waste per day.  Screening – Fine mesh screens are provided to remove fine matters from pesticide wastes.  Equalisation tank- Equalization tank provided in pesticide industry consists of a wastewater holding vessel or a pond large enough to dampen flow and/or pollutant concentration variation that provides a nearly constant discharge rate and wastewater quality. The detention time taken here is about 24 hrs. In this there are 2 equalisation tanks are provided.  Settling tank- The NaOH is added to the settling tank for the correction of pH before the extended aeration process.  Fenton oxidation- In this the dose of H2O2 is given about 2500mg/l for the oxidation & FeSO4 as a catalyst dose about 833mg/l. With the ratio about H2O2:Fe as 1:3. & removal percentage is about 80%.Before the Fenton oxidation the acid dosing is given for the lower the pH value because it will work only at lower pH value. After the Fenton process the pH is increased by addition of NaOH.  Extended aeration- The extended aeration is complete mix flow regime. The process employs low organic loading, high MLSS, long detention time, low F/M. As the influent coming from the pesticide waste the assumed removal efficiency is here about 65%.  Secondary settling tank (SST) – The biomass is generated in the aeration tank is flocculent & quick settling it is separated from the aeration sewage in secondary tank & recycled continuously to the aeration Tank as essential future of the process.
    • PESTICIDE INDUSTRY Page 29  Effluent sump- The treated effluent is collected in this sump & is given for the further treatment of activated carbon.  Activated carbon treatment – Activated carbon adsorption is process for adsorption of organics in wastewater from pesticide industry. In the pesticide industry, GAC is widely used. The treatment removes the concentration of pesticides at very low level. The effluent from the sump is pumped into the activated carbon tower. Process MLSS (mg/l) MLVSS/ MLSS F/M HRT (hrs.) Vol. Loading (kg BOD/m3) SRT (days) Qr/Q BOD rem- oval(%) Kg O2/kg BOD removal Air req./kg BOD removal Extended aeration complete mix flow 3000- 8000 0.6 0.15- 0.05 18- 36 0.2-0.4 20-30 0.35- 1.5 65 1-1.2 100-135 Parameter Waste characteristics Fenton Oxidation Settling tank Extended Aeration (65% removal) SUSPENDED SOLIDS (98%) 2000 40 COD (80%) 1372 274.4 96.04 MANGANESE ( 98%) 215 4.3 1.1 ZINK (98%) 4 0.08 0.02
    • PESTICIDE INDUSTRY Page 30  References-  EPA report on Pesticide industry  Use of Fenton's Reagent for Removal of Pesticides from Industrial Wastewater- research paper  Environmental, Health, and Safety Guidelines for Pesticide Manufacturing, Formulation, and Packaging- WHO report  PFPR Operations- EPA report  Ecological Effects of Pesticides- document by Calicut university, India  Pesticide use and application: An Indian scenario- research paper  Treatment of Pesticide Industry Wastes- by Wang & Hung  Industrial waste water treatment- A.D. Patwardhan  Central pollution control board- website  I S Codes on pesticides