Environmental Challenges Facing Sugar Sector in Pakistan By Talha Usman M.Sc(Env,Science)
Waste produce during sugar Production:Mill House Sugar cane(waste & by product)Wastewater from bearing house of the millcontain SS and oil contents also includewashing water used for floor cleaning,whichcontain sugar content like BagasseProcess House Sugar Juice(waste & by product)Filter cake generates aggressive effluentslike BOD5,COD,TDS and Molasses
Boiler House Bagasses,Furnaceoil (Waste & by product) Fly ash, smoke, flue gassesCooling pond water andchemical (waste & by product)
Environmental Solution It can be classified into three main categories.1. In-House improvement options (Waste reduction at source )2. Air & Noise Emission control measures3. Waste water treatment technologies for NEQS compliance
In-House improvement options ( Waste reduction at source)Flow measurement through flow meter and monitoring atinlet and out let of each consumer unit at the mill for betterwater management practices.Use of optimum imbibitions rate to save energy in terms ofsteam consumption and to reduce organic and hydraulicload from the process houseDry cleaning of mill floors with bagasseEfficient operation of evaporators will reduce wastedisposal problems and enhance sugar recovery.overloadingof evaporators and vacuum pans, boiling at excessive rates,operating them at incorrect liquid levels,and variation ofvacuum lead to a loss of sugar through condenser water.Recycling of cooling and condenser water
The simple measure of controlling spillover of molassescan very significantly reduce the organic pollutioncontent(BOD5) of the wastewater stream.Segregation of oil from other effluent will allow for therecovery and reuse of lubricating oil and reduce soilcontamination when wastewater is applied for irrigation.Controlling the mixing of filter mud with wastewater canvery significantly reduce the organic and inorganic pollutioncontent of wastewater stream.Routine inspection of units, particularly pumps, pipes andother vessels.Reducing water used for floor sweeping and washing byrecovering water from various mill processes and reusing itfor cleaning purposes.Detaining filter cloth washing in a holding tank for a shorttime before being allowed to mix with other effluents fromthe mill will reduce the contamination in the condenser
Installation of circular mist eliminators or demistersconstructed of stainless steel in the multiple effectevaporators can eliminate sugar entry in condenser water.Bagasse management is of paramount importance inestablishing overall energy efficiency in the mill .steam andpower generation and reduction in fuel oil consumption arelargely dependent on an adequate supply and efficientutilization of bagasse .Benefits will also result from ensuringthat maximum moisture has been removed beforebagasses is used in the boiler.As far as air emissions are concerned the first step shouldbe to set up a system of regular monitoring of stackemissions with periodic boiler tune ups.this canconsiderably increase boiler efficiency and minimizationemissions.Reduction of the use of Lead sub Acetate(Toxic chemical)
Air and Noise Pollution ControlAir Emission Control Methods:1. Regular monitoring of stack emissions2. Settling chamber (These chamber will remove large particulate matters)3. Wet collectors (Mostly available in simply spray tower is an effective method for removing particulate matters.)4. Gas Scrubber5. Electrostatic precipitator
Air and Noise Pollution ControlNoise Pollution Control Methods:1. Sound reduction at source (using silencers)2. Interrupting the path of the sound (using sound barrier)3. Protecting the recipient (using Ear muffs,plug)
Strategy for wastewater ManagementSteps for wastewater minimization:Arrangement to divert the washing of Lime house and grit washing to condenser water channel to reclaim both the water and residual Lime which helps to make up the condenser water pH.Collection and recirculation of leakage from pumps glandsCollection of centrifugal house floor washing and pumping it back to raw juice.Using sugar contaminated condensate for maceration at mill house.Recirculation of all cooling waters.Reclamation of hot water and vapors from boiler blow
Drainage within the plant should not be allowed as this leads to indiscriminate use of water.Arrangement for collection of all cooling waters should be made designed for cascade cooling of water which follow the recirculation.Boiler feed water requirement will be met by condensation from vapors cells, if need be supplemented by the condensate from pans, the collection system should be tow ways.Vapour condensate from vapour line juice heaters is collected and used in maceration.The overflow of spray pond and boiler blow downs can be used for spraying over bagasse and fly ash in dumping yard to prevent the hazard of fire.Prepare the Do,s and Don,t for the plant personals.
All ground water tube wells have meters. Daily recording and monitoring shall help in reduction of ground water extraction through effluents generation.Set up a pit for collecting juice contaminated water to reduce sugar content in washing and cleaning water.Monitor and follow up the quality and quantity of pollution sources to prevent additional polluting effluent.Precipitation and filtration of flue gas washing water will regenerate it into a colorless and transparent state. This regenerated clean water can be reused in the flue gas washing system.Training and developing the concept of water conservation to managers, operators and labors.Organizing the internal seminar giving opportunity to express the views to suite the environmental and company
Wastewater Treatment TechnologiesSolution Technical Characteristics Operational CharacteristicsLagoon Anaerobic lagoons are BOD5 loading kg/m3? Leasts deep earthen basins used efficient for high strength organic BOD5 removal efficiency ? wastewater with high solid 85-90% concentration. Energy requirement for Facultative lagoons are aeration kwh/kg BOD treated ? earthen basins filled with Moderately efficient screened or primary Hydraulic detention time ? effluent in which Very high stabilization of east is mechanical complexity ? low brought about by a combination of aerobic, Reactor resilience for power anaerobic and facultative failure and shock loads ? bacteria. Moderate to high Aerobic lagoons are large, By-product ? Nil shallow earthen basin used for Land requirement ? large treatment of wastewater by natural processes.
Solution Technical Characteristics Operational CharacteristicsLagoons Maturation ponds are low On –site environmental impact rate stabilization ponds –soil infiltration and aerosols usually designed to provide dispersion for secondary effluent Man power requirement ? polishing and seasonal Skilled nitrification. Frequency of repair & maintenance ? mediumTricking Wastewater flows from BOD5 loading kg/m3 ? LeastFilters top to bottom, dispersed efficient over filter material BOD5 removal efficiency ? 85 (stones,plastic during 90% which soluble compounds Hydraulic detention time ? are removed and, to a Most efficient lesser extent, solids are Land requirement ? Small taken up into the biofilm adhered to the carrier Man power requirement ? material. Skilled Mechanical complexity ? Low By product ? nil
Solution Technical Characteristics Operational CharacteristicsUpflow The basic idea of this BOD5 loading kg/m3/d ? VeryAnaerobi system is that the flocs of efficientc Sludge anaerobic bacteria will tend BOD5 removal efficiency ? 80Blanket to settle under gravity, 90 %(UASB when applying a moderate Energy requirement for aerationReactor up flow velocity of water. In kwh/kg BOD treated ? Most this way no separate efficient sedimentation tank is Hydraulic detention time ? Mos necessary. efficient The waste water passes Mechanical complexity ? low the reactor from the bottom to top. To guarantee By product ? Biogas sufficient contact between On site environmental impact ? the incoming wastewater Nil and the bacteria in the Land requirement ? Small sludge layer the Man power requirement ? wastewater is fed evenly over the bottom of the Highly skilled reactor .Further mixing is Frequency of repair & brought about by the maintenance ? low production of the gas
Solution Technical Characteristics Operational CharacteristicsActivated Many variations of BOD5 loading kg/m3/d ? VerySludge activated sludge treatment efficientTreatmen exist, depending on load BOD5 removal efficiency ? 85t characteristics. Activated 95% sludge treatment is most Energy requirement for aeration appropriate for high kwh/kg BOD treated ? Least organic pollution loads. efficient Most successfully applied if Hydraulic detention time ? hourly flow is low. Moderately efficient System consist only of mechanical complexity ? High aeration tank (operated as fill and draw system ) and Reactor resilience for power mechanical surface failure ? Low and for shock loads aerators. Aeration and ? Moderate sedimentation takes place By product ? Nil in the same reactor on the On site environmental following cyclical principle: impacts ? Aerosol dispersion and feeding and aeration of the reactor during a certain period, noise switch off the aeration, followed Land requirement ? Moderate by settling of the sludge and Man power requirement ? discharge of the effluent. Highly skilled
End-of-pipe Treatment in sugar millsCombination of Lagoons in Sequence(Anaerobic,Facultative and Maturation)Preliminary design and costing of this option?for a mill generating6,000 - 7,000mg/l BOD5 ? Suggests that to achieve of 90%removal efficiency the lagoons system would require a totalsurface area of 120 hectares, a total volume of 1.5 million cubicmeters,and a total retention time 216 days.The exorbitant level ofretention time, land requirement and high cost of lining make thisinadvisable for local sugar mills. However, unlined lagoons,though pose serious threat to ground water quality, can also betaken into consideration after careful analysis of environmentalcondition around the mill.
End-of-pipe Treatment in sugar millsCombined Treatment System Comprising of aUASB Reactor and an Activated Sludge SystemWhen used alone, the activated sludge system has a highoperational cost because of the energy required for aeration.Combining it with a UASB Reactor significantly reduces this cost.The UASB Reactor can remove about 80 - 90 % BOD5;inaddition, a by-product of the process is methane which can thenbe used as a source of energy for the boiler. After passingthrough the UASB Reactor, the effluent can passed through theActivated Sludge System for treatment of remaining BOD5. Thecombined system will achieve the same pollutant removalefficiency as the Activated Sludge System but at lower cost. Thiscombined system will bring the present BOD5 and suspendedsolids level near or below the NEQS.Such a system will requirearound 1,500 - 3,000 square meters of land and its annualoperation and maintenance expenditure would be approximately10% of its total cost .with in–house improvement USAB reactoras single treatment can be applied.
Health RisksBagasses dust, fly ash and high noise levels (reaching up to109dB)are particularly health irritant.Excessive exposure tofly ash and bagasse dust may cause irritation toeyes,asthma,and other respiratory diseases includingbagassosis(a lung disease caused by inhalation of bagassedust)Dust prone areas ,including cane preparation and theboiler house, should be carefully monitored. Nuisance dustlevels should be controlled properly.Dermatitis or skindisease is a major health complaint resulting from chemicalburns,and contact with lime and sugar.Toxic gassesincluding sulfur dioxide,caustic fumes are released atvarious stages of the process and are health hazards.Fluegas which is produce by the combustion of bagasse causea visual nuisance and have serious health concern.Theseproblems are particularly high in boilers due to not equippedwith scrubbing or cyclone systems.
ISO 14001A set of environmental managementrequirements for environmentalmanagement systems.The purpose of thisstandard is to help all kinds of organizationsto protect the environment, to preventpollution, and to improve their overallenvironmental performance.
Components of ISO 14001Environmental policyPlanningImplementationMonitoring and evaluationReview
Requirements for ISO 14001 CertificationExistence of EMSEffective operation of EMS for at least three monthInternal audit conducting capacity should exist in the companyEnvironmental training has been imparted to its employeesDocuments are maintainedManagement review has been conducted
ISO 9001 & ISO 14001 will help you:Promote & Enhance your business & marketing effortsIncrease income revenuesKeep your customers happy & satisfied.
By having ISO 9001 & 14001 Certification,you gain:Reduced liabilities & added protectionExtended management & operation tools, including those to reduce “non quality” costs.Improved control, to manage internal andexternal activities.Improved quality for products and services.Improved supply schedules for products and services.A better feeling caused by better managed environmental care.
Environmental Management Systems:It is set of policy measures, managementactions, operating procedures,documentation and record keeping,definedresponsibilities and accountabilities ofpersonals within an organization to addressits environmental issues.
Concept of EMSManagement review Env, consequences of operationEnvironmental policy Set objective for Env,performanceAction planning To achieve objectiveImplementation To monitor performance against these objectivesCorrective action For continue improvement
Environmental Management Systems BenefitsThe benefits of an EMS and registration of theEMS to ISO 14000 are organized into thesecategories:Increased profitsOperationsMarketingRegulatory ComplianceSocial Status