Leather/Skin/Hide Processing Industry - Environmental Clearance

Leather / Skin / Hide Processing Industry (Tannery)3.3.2 Air emissionsAir emissions from tanning facilities include the following:Table 3-4: Sources of Air Emissions and Preventive MethodsEmissionto AirOrganicSolventsVOCsSulfidesAmmoniaDustSource Operations inTanneryDegreasingFinishingSpray-finish MachinesDryersBeam house andEffluent treatmentBeam HouseDelimingDehairingDrying after dyepenetrationStorage handling ofpowdery chemicalsDry shavingBuffingDust removal machinesMilling drums, StalkingSuggestive Methods of Prevention Usage of water-based formulations for spraydyeing Usage of roller coating techniques or curtaincoating machines wherever applicable Usage of spraying units with economizers andhigh volume / low-pressure spray guns Avoid usage of internationally banned solvents Usage of wet scrubbers, activated carbonadsorption, bio-filters (to remove odors),cryogenic treatment, and catalytic or thermaloxidation. Maintain a basic pH over 10 in the equalizationand sulphide oxidation tanks. Avoid breeding anaerobic conditions in sulphatecontaining materials. Add manganeese sulphate to treated effluent. Use adequate ventilation Adequate ventilation followed by wet scrubbing centralized system employing cyclones Usage of scrubbers/bag filters, as needed.Emissions of sulfur dioxide may occur during bleaching, post-tanning operations, orcarbon dioxide (CO 2 ) deliming, but they are not typically a significant source ofemissions.Table 3-5: Odour Emissions to AirOdorousEmissionsto AirSource Operations in TannerySuggestive Methods of PreventionNH 3 Beam house operations Prompt curing of raw hidesH 2 SBeam house operationsETP collection tanksETP Primary Treatment Units Reduce the time that sludge remains inthe thickener, dewater thickened sludgeby centrifugation or filter press, and drythe resulting filter cake. SludgeTGM for Tanneries August 20103-12