PCFC ENVIRONMENTAL GUIDELINES (EGs)
TABLE OF CONTENTS
EG No.
Description
1. Air Environment Guidelines
1.1: Air Environment General Guidelines 1.2: Chimneys and Dispersion Modeling 1.3: General Industry Air Emissions Guidelines 1.4: Source Emission Criteria- Air Pollutants 2. Large Boilers and Furnaces
2.1: General Guidelines
2.2: Technical Guidelines for Steam Boiler Installation 3. Chemical Fertilizer Works
4. Ammonia Works 5. Sulphuric Acid Works 6. Lead Works
7. Mineral Works
8. Iron and Steel Works-Foundries 9. Secondary Aluminum Works 10. Chemical Incineration Works 11. Cement Works
12. Di-isocyanates Works
13. Petroleum Works – Refineries
14. Chlorine and Hydrochloric Acid Works 15. Iron and Steel Works
16. Montreal Protocol for Ozone Depleting Substances 17. Control of Substances Hazardous to Health and a Danger
17.1: Handling and Processing 17.2: Storage
17.3: Guidance Note
17.4: General Guidelines for Dangerous/ Hazardous Materials Handling and Storage 17.5: PCFC Requirements for Handling, Export of Radioactive Substances
18. Water Environment Guidelines
18.1: Water Environment General Guidelines
18.2: Treated Wastewater Disposal in Harbour/Gulf (Open sea)
18.3: Elements to be taken into Account in the Issue of the Authorization for Discharge of Treated Waste in to Harbour/Open Sea
18.4: Wastewater Criteria at Point of Discharge to Marine Environment/Harbour: Standards for Discharge of Waste to Harbour
18.5: Wastewater Pre-Treatment Criteria for Industrial Effluent to Dubai Municipality Sewers
19. Environmental Management Tools (EMT)
20. Guidelines for Conducting Environmental Impact Assessment (EIA) Study in PCFC/Pre-qualified Consultants list for EIA/RA Studies.
21. Best Available Techniques (BAT) and Best Practicable Environmental Option (BPEO) 22. Guidance for Linear Soakaways Installation
23 Guidance for Groundwater Monitoring Wells Installation 24. Energy Efficiency
25. EHS Standards References
26. DUCAMZ Environmental Guidelines. 27. Guidelines for Cleanliness
PCFC-EGs-Table of Contents i Revised: 23/04/03
28. General Environmental Guidelines for Manufacturing/Assembly/Service Industries. 29. EHS Performance Audits
30. Guidelines for Conducting Waste Audits in PCFC.
31. Environmental Guidelines for Gold and Diamond Facilities in DMCC 32. Energy, Water Conservation and Management Guidelines
33. Glass Recycling
34. Environmental Reporting
35. Cleaner Production, Waste Minimization and RRR Options 36. Waste Management in PCFC
PCFC-EGs-Table of Contents ii Revised:23/04/03
ENVIRONMENTAL GUIDELINE No.1
AIR ENVIRONMENT GUIDELINES1.1 AIR ENVIRONMENT GENERAL GUIDELINES:
There are some general guidelines/features which are common to most works. Such guidelines are outlined below.
a. As part of proper supervision, the owner shall make tests and inspections of the process at frequent intervals as required by the Authority.
b. The results of all tests shall be recorded for inspection by the Authority representatives. c. Adequate facilities for sampling shall be provided on chimneys and ducts.
d. The reference test method for particulate emissions is by the procedure of British Standard 3405:1983 or similar relevant standard.
e. All limit values including EGs are expressed as being at the gas reference conditions of 30oC and a
pressure of 1 bar, without correction for water vapour content. f. Emissions shall be monitored continuously wherever practicable. g. Roads and operating areas shall be hard surfaced and kept clean. h. A good standard of housekeeping is essential.
i. Staff at all levels shall receive proper control training and instructions in their duties, with special emphasis on start-up, shut-down and abnormal conditions.
j. Chimney heights shall be determined by the Authority taking into account all the relevant information on throughput, type of material, quality of emission, fuel type and rate of usage, local circumstances, etc.
k. Dry emissions shall normally be vented to air with an efflux velocity of 10 to 15 m/sec at full load. l. When waste gases are wet, or have been in contact with liquids, the maximum chimney velocity shall
be 9m/s to prevent the emission of liquid droplets physically stripped from the wet inside chimney surfaces by high velocity gases.
m. The minimum height of any chimney shall not be less than 3m above the ridge of any tallest building to which it is attached or adjacent.
n. There shall be suitable means for dealing with spillages, as agreed with the Authority.
o. The construction of any boiler, heater, oven etc shall comply with PCFC requirements (see relevant EG)
p. For any spray painting operation, a proper painting booth should be constructed with a proper extraction/filtration system to the Authority’s satisfaction.
q. Proper extraction/filtration system to be provided for the air borne emissions from the proposed machinery. The detailed drawings to be submitted to PCFC for approval.
PCFC-EG#1 Page 1 of 4 Revised:23/04/03
1.2 CHIMNEYS AND DISPERSION MODELING
When the best practicable control means for prevention of emission of noxious or offensive substances have been used, the second part is to render harmless and inoffensive such substances as may be discharged. This is achieved by dispersion from suitably tall chimneys, taking into account the composition, volume rate of emission and temperature of the waste gases. The final decisions on the heights and diameters of chimneys shall be taken by the Authority.
For purposes of deciding on chimney heights of industry in the Free Zone, industry is divided into two parts:
(a) where chimneys are needed to disperse the products of combustion of fuel, and (b) where chimneys are needed to disperse airborne emissions from process operations.
In the case of (a), for relatively small plants where the heat output is below 30 MW, the publication on “Chimney Heights” issued by the UK government and obtainable from HMSO is used for determining heights of chimneys. It is a well - tried document over many years and allows multiple sources to be sited in industrial areas without exceeding permitted ground level concentrations. On a case-by-case basis air dispersion modeling would be required from the clients.
1.3 GENERAL INDUSTRY AIR EMISSIONS GUIDELINES
a. Particulate matter Emission
Limit
(i) Inert dust in ducts and chimneys from combustion sources. 250 mg/m3
(ii) Fugitive dust - there shall be no significant visible emission except from
combustion sources.
(iii) There are many dusts and fumes which can have a harmful or nuisance effect on humans, animals, vegetation and materials of construction and for which special limits of emission are required. The following list is not exclusive and substances not on the list will be considered on their merits.
Iron oxide fume from oxygen refining 75 mg/m3
*Petroleum - solids from catalytic crackers 100 mg/m3
*Petroleum - furnace carbon black 5 mg/m3
Phosphorus (as P2 O5) 5 mg/m3
Tar fumes 20 mg/m3
Vinyl Chloride 10 mg/m3
*Note: Desired range of Sulphur Recovery Units (SRUs) efficiency 98- 99.9%
All volumes are referred to standard conditions of 30oC and 1 bar; electricity works burning fossil
fuels are also referred to a standard of 12 percent carbon dioxide in the waste gases.
(iv) Routine methods of assessment may be used by agreement with the Authority, and continuous monitoring instruments shall be fitted wherever practicable.
(v) Emissions in normal operation shall be free from visible smoke and in any case shall not exceed 250 mg/m3.
(vi) Sand is prohibited for use as blasting media. Use of any abrasive blasting media containing more than 1% free silica shall not be used in abrasive blasting operations in PCFC.
PCFC-EG#1 Page 2 of 4 Revised:23/04/03
(vii) All abrasive blasters operating in PCFC shall use a recyclable non-metallurgical abrasive material.
b. Gaseous Emissions Emission
Limits
Amines - total amine 5 p.p.m v/v
- trimethylamine 1 p.p.m v/v
Asphalt fumes 5 mg/m3
The waste gases from industrial processes are often a mixture of acid gases and whilst it is not practicable to measure each component separately, it is convenient to measure the total acidity and to express it as sulphur trioxide (see below table) as a basis for comparison.
1.4 SOURCE EMISSION CRITERIA - AIR POLLUTANTS
SUBSTANCE SYMBOL SOURCES
EMISSION LIMITS (mg/Nm3)
Visible Emissions Combustion sources
Other sources
250 none
Carbon Monoxide CO All sources 500
Nitrogen Oxides
(Expressed as nitrogen
dioxide)
NOx Combustion sources Material producing industries Other sources Gas fuel-350 Liquid fuel-500 1500 200 Sulphur Dioxide SO2 Combustion sourcesMaterial producing industries Other sources 500 2000 1000 Sulphur Trioxide
Including Sulphuric Acid Mist (Expressed as sulphur trioxide)
SO3 Material producing industries Other sources 150 50 Total Suspended Particles
TSP Combustion sources Cement Industries Other sources 250 50 150 Ammonia and Ammonium
Compounds (expressed as ammonia) NH3 Material producing industries Other sources 50 10
Benzene C6H6 All sources 5
Iron Fe Iron & Steel foundries 100 Lead and its compounds
(expressed as lead)
Pb All sources 5
Antimony and its Compounds (Expressed as antimony) Sb Material producing industries Other sources 5 1 Arsenic and its Compounds
(expressed as arsenic)
As All sources 1
Cadmium and its compounds (expressed as cadmium)
Cd All sources 1
Mercury and its compounds (expressed as mercury)
Hg All sources 0.5
Nickel and its compounds (expressed as nickel)
PCFC-EG#1 Page 3 of 4 Revised:23/04/03
Copper and its compounds (expressed as copper)
Cu All sources 5
Hydrogen Sulphide H2S All sources 5
Chloride Cl Chlorine Works
Other sources
200 10
Hydrogen Chloride HCI Chlorine Works
Other sources
200 20
Hydrogen Fluoride HF All sources 2
Silicon Fluoride SiF4 All sources 10
Fluoride and its Compounds Including HF & SiF4
(expressed fluoride)
F- Aluminum smelters
Other sources
20 50 Formaldehyde CH20 Material producing
industries Other sources
20 2
Carbon C Anode production
Waste incineration
250 50 Total Volatile Organic Compounds
(expressed as total organic carbon -TOC)
VOC All sources 20
Dioxins and Furans All sources 1 ng TEQ/m3
Notes:
1. The concentration of any substance specified in the first column emitted from any source specified in the third column shall not at any point before admixture with air, smoke or other gases, exceed the limits specified in the fourth column.
2. “mg” means milligram; 3. “ng” means nanogram.
4. “Nm3” means normal cubic meter, being that amount of gas which when dry, occupies a cubic meter
at a temperature of 25 degree Centigrade and at an absolute pressure of 760 millimeters of mercury (1 atm);
5. The limit of “Visible Emission” does not apply to emission of water vapour and a reasonable period for cold start up, shutdown or emergency operation.
6. The measurement for “Total Suspended Particles (TSP)’’ emitted from combustion sources should be @12% reference CO2.
7. The total concentration of the heavy metals (Pb, Cd, Ni, Hg, Cu, As & Sb) must not exceed 5 mg/Nm3.
8. VOC limit is for unburned hydrocarbons (uncontrolled).
9. The emission limits for all the substances exclude “Dioxins and Furans” conducted as a daily average value.
10. TEQ means “Total Equivalent Quantity.” Dioxins and Furans”. Average values shall be measured over a sample period of a minimum of 6 hours and a maximum of 8 hours. The emission limit value refers to the total concentration of dioxins and furans calculated using the concept of toxic equivalence (Refer to PCFC-ER, 3rd Edition for more details).
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
PCFC-EG#1 Page 4 of 4 Revised:23/04/03
ENVIRONMENTAL GUIDELINE No.2
LARGE BOILERS AND FURNACES2.1 GENERAL GUIDELINES
(i) These notes apply to works in which solid, liquid or gaseous fuel is burned, having a heat input equal to or greater than 30 megawatts (100 million BTU/h). A guide for boiler installation (available from EHS Dept. separately) should be used as a reference.
A. Sampling, Measurement Of Emissions And Monitoring
(i) Emissions of sulphur dioxide, nitrogen oxides and particulate matter, including smoke, from each boiler or furnace shall be monitored continuously and shall be displayed on a meter visible to operating staff. Sampling ports and ladder/flanges facilities to be made available for monitoring. (ii) The accepted form of particulate emission monitoring is by optical density measurements for the fine
particles and by a gravimetric method for coarse particles.
(iii) Zero and calibration checks on monitoring instruments shall be carried out by the company. The reference test method for particulates is by the procedure of British Standard 3405:1983.
(iv) All limit values in these notes are expressed as being at the reference conditions of 30oC and 1 bar
and a standard of 12 percent CO2 in the waste combustion gases.
B. Emission Limits And Controls
(i) For oil-fired plant, sulphur dioxide removal equipment shall be installed with a removal efficiency of not less than 99.9 per cent.
(ii) The design of the combustion system on oil-fired plant shall aim to limit the emission of nitric oxides to the air to a concentration not exceeding 500 mg/m3 in normal operation for oil-fired.
(iii) The concentration of particulate matter in emissions to air shall not exceed 500mg/m3 as a 2-hour
average.
(iv) Emissions in normal operation, shall be free from visible smoke and in any case shall not exceed 250 mg/ m3.
(v) For non-combustion plant, the concentration of particulate matter in emissions to air from the handling, crushing or screening of solid materials used in or produced by the combustion process shall not exceed 250 g/m3.
C. Operational Controls
(i) Means for preventing the emission of acid soot from oil-firing shall be operated continuously and the temperature of the gases in the chimney shall normally be maintained at not less than 150oC.
(ii) Chimneys, flues and the duct work leading to the chimney shall be insulated to prevent liquid condensation on internal surfaces.
PCFC-EG#2 Page 1 of 2 Revised:23/04/03
D. Chimneys
(i) Chimney heights shall be assessed on the basis of estimated ground-level concentrations of the residual gases and taking account of local circumstances and recognized air quality standards or criteria.
(ii) The efflux velocity of the emitted hot, dry gases shall not be less than 15 m/s at maximum continuous rating for boilers or furnaces from 30 to 700 MW thermal rating, and not less than 18/m/s for combustion plant rated above 700 MW.
(iii) For non-combustion processes, chimneys shall normally be designed for an efflux velocity of not less than 15 m/s, but where a wet method of arrestment has been used, the velocity in the chimney shall not exceed 9 m/s to avoid droplet entrainment from the chimney surface.
2.2 TECHNICAL GUIDELINES FOR STEAM BOILER INSTALLATION
Prior to any steam boiler installation in the Free Zone, the following Health, Safety and Environment Guidelines are to be fulfilled:
(i) Details of the steam boiler including capacity, fuel type (with sulphur content < 1%), fuel rate, fuel sulphur content etc. have to be provided.
(ii) Boiler room height and any adjacent building height to be provided. Boiler chimney height calculation will be provided by PCFC to the client.
(iii) The fuel tank should be bunded with impervious bund wall including the bund floor. The same should be designed to confine fuel of 110% fuel tank capacity and the underground bund area to be lined with proper PVC lining. Details of the bund wall volume calculation and design should be provided.
(iv) Proper drainage facility should be provided for the boiler condensate and blow down to PCFC satisfaction, away from the domestic drainage of the facility. A detailed drawing in this regard should be provided.
a. Conditions mentioned under the title ‘Large Boilers and Furnaces’ should be fulfilled and acknowledged.
b. Proper sampling point to be provided on the chimney for emission quality checks.
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
ENVIRONMENTAL GUIDELINE No.3
CHEMICAL FERTILIZER WORKS
1 INTRODUCTION
These notes apply to processes for the manufacture of superphosphate, phosphoric acid, ammonium nitrate and ammonium phosphate, the granulation of compound fertilizer and the production of complete fertilizer mixtures by melt granulation or prilling.
2 SAMPLING, MEASUREMENT OF EMISSIONS AND MONITORING
The tests normally carried out are for total acidity and hydrogen chloride, ammonia, hydrogen sulphide, fluoride and particulates, depending on what is being processed at the time of sampling.
3 EMISSION LIMITS AND CONTROLS
A Phosphate Rock Processing
i. All emissions to the air shall be substantially free from persistent mist or fume, and free from droplets.
ii. The concentration of particulate matter in emissions to the air from phosphate rock grinding shall not exceed 250 mg/m3
B Superphosphate and Phosphoric Acid Plant
i. The total acidity of all process gases emitted to the air shall not exceed 150 mg/m3, expressed as
sulphur trioxide.
ii. The hydrogen sulphide concentration in all process gases shall not exceed 5 p.p.m v/v.
iii. Waste or recovered acids likely to cause the emission of odorous substances shall not be used without prior evaluation and agreement of the Authority.
C Granulation and Prilling Plant
i. The concentration of particulate matter shall not exceed 150 mg/m3.
ii. The concentration of hydrogen chloride shall not exceed 200 mg/m3.
iii. The concentration of ammonia (free) shall not exceed 50 mg/m3 to meet 2 ppm ambient criterion
iv. The concentration of fluorides (as HF) shall not exceed 2 mg/m3.
v. VOCs should be removed/incinerated 99.9% to ensure maximum emission of 20 mg/ m3.
D Ammonium Nitrate
i. The concentration of free ammonia from prilling plants shall not exceed 10 p.p.m v/v.
ii. The concentration of free ammonia from neutralisers and evaporator shall not exceed 50 p.p.m. v/v.
iii. The concentration of particulate matter from evaporators, prilling towers and melt granulation plants shall not exceed 150 mg/m3.
iv. The concentration of particulate matter from coolers and dryers, and from other contained emissions shall not exceed 150 mg/m3.
E Ammonium Phosphate
i. The concentration of free ammonia shall not exceed 10 p.p.m v/v.
ii. The concentration of fluoride shall not exceed 20 mg/m3 expressed as hydrogen fluoride.
iii. The concentration of particulate matter from all contained sources shall not exceed 150 mg/m3.
F Operational Controls
i. Emissions from rock grinding, evolution of acid gases from dissolving plant and emissions from granule preparation vessels, dryers and coolers, shall be contained and ducted to a suitable treatment plant acceptable to the Authority to meet the limit values above.
ii. Inlet and outlet gas temperatures on granulation plants shall be continuously monitored to prevent decomposition of the materials. Where ammonium nitrate is used, provision shall be made for quenching any exothermic decomposition occurring in the dryer. Measures shall also be taken to prevent the possibility of unburnt fuel entering the dryer.
iii. It is preferable that ammonium nitrate neutralisers should be fully enclosed with no direct vent to air, but if this is not practicable then suitable treatment equipment shall be installed to meet the limit values in above paragraphs. Total condensation evaporators are preferred to emission treatment plant.
G Material Handling and Storage
i. Stocks of dusty material shall be stored under cover to prevent wind-whipping. Loading to and from stockpiles shall be carried out so as to minimize airborne dust.
ii. Storage silos for dusty material shall be vented to air through suitable equipment to prevent dust emissions.
iii. All handling, transport and processing of dusty materials shall be carried out in a manner which gives rise to no significant visible emission.
iv. The storage and handling of liquids shall be carried out in such a manner as to prevent the emission of noxious or offensive substances to the satisfaction of the Authority.
H Chimneys
i. The minimum height for process gases shall be 37m. Discharge heights for other emissions shall be agreed with the Authority and shall not be less than 3m. above roof ridge level of nearest tallest building. Emissions should take place from the minimum number of chimneys and it is good practice to combine clean, warm, dry emission with wet emissions where practicable.
ii. To reduce the risk of mist formation, emissions containing ammonia should not be mixed with other emissions, and outlets should be spaced as far as practicable from outlets discharging acidic gases.
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
ENVIRONMENTAL GUIDELINE No.4
AMMONIA WORKS
1 INTRODUCTION
These notes apply to all new ammonia production plants and works in which ammonia is stored and handled in anhydrous form in fixed tanks with an aggregate capacity exceeding 100 tons.
2 EMISSION LIMITS AND CONTROLS
(i) A single emission limit for ammonia is not readily applicable to this class of works. Design criteria for the discharge from individual plant exits shall be discussed with the Authority and where practicable should aim for a concentration of free ammonia (point source limit 50 mg/m3) shall be so that ambient
criterion of 2 ppm (fenceline) is met at all times.
(ii) All emissions shall be free from droplets and persistent mist.
(iii) The emission of combustion products from reformer or other furnaces shall be maintained free from visible smoke or fumes during normal operation.
3 OPERATIONAL CONTROLS
(i) Reformer production gas (‘make gas’) during start-up or shut-down procedures shall be vented to a suitable flare, or when not combustible, discharged at an agreed height.
(ii) Carbon dioxide discharged to atmosphere from CO2 absorber - stripper units shall at all times pass
through an efficient droplet and spray eliminator system. This shall apply also to emergency venting systems, and extra care shall be taken when absorbents of high toxicity are used.
(iii) All gas purged from the synthesis loop during normal operation shall be burned in a suitable furnace or flare.
(iv) Gaseous ammonia from pressure relief systems shall when practicable be vented to a flare or discharged at an agreed height.
(v) Storage facilities for ammonia liquor shall be vented to a suitable absorber.
(vi) Means shall be provided for minimizing escapes of ammonia from loading or unloading facilities. (vii) Storage for light liquid hydrocarbon feedstocks shall be fitted either with double-sealed floating
roofs, or with a vapour recovery system, or equivalent means for minimizing vapour loss.
4 CHIMNEYS
(i) Chimney heights (min.37m) for ammonia works shall be agreed with the Authority on the basis of the expected maximum rate of emission of ammonia or any other significant pollutant, taking into account emergency situations.
(ii) To reduce the possibility of mist formation, chimneys for emissions containing ammonia should be spaced as far as practicable from chimneys discharging acid gases.
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
ENVIRONMEMNTAL GUIDELINE No.5
SULPHURIC ACID WORKS
1 INTRODUCTION
These notes apply to the manufacture of sulphuric acid by the double-contact process and to the production of sulphur trioxide for use in chemical processes.
2 SAMPLING, MEASUREMENT OF EMISSION AND MONITORING
(i) As part of proper supervision, the owner shall make tests and inspections of the process. Tests shall normally be taken not less than once per day from each exit and adequate facilities shall be provided on chimneys and ducts.
(ii) Continuous monitors for emission of sulphur dioxide shall be installed, with sufficient range to cover start-up conditions.
(iii) The Reich test or an agreed alternative shall be used to determine the sulphur dioxide (SO2) content
of the strong gas fed to the first catalytic converter. Allowance shall be made for the use of quench or additional air.
3 EMISSION LIMITS AND CONTROLS
(i) During normal operation the proportion of sulphur dioxide emitted to air shall not exceed 2000 mg/m3. SO3, including Sulphuric Acid mist, shall not exceed 150 mg/m3.
(ii) The waste gases shall be substantially free from persistent mist.
4 OPERATIONAL CONTROLS
(i) An efficient mist eliminator shall be provided after the final absorber. (ii) Means for rapid warning of absorber acid feed failure shall be installed.
(iii) Means for indicating the sulphur feed rate and the air flow rate to the sulphur burner shall be installed.
(iv) Means for the early detection of leaks on acid coolers shall be provided.
(v) When sulphuric acid is being transferred or loaded into tanks, non-splash techniques and bottom
loading shall be practised. (vi) Adequate preheating facilities shall be provided to enable at least two catalyst stages to “strike” as
soon as sulphur dioxide is fed to the system.
(vii) Absorber acid strength and temperature shall be adjusted to optimum before the start-up.
(viii) By careful preparation and control, the duration of abnormal emissions on start-up shall be minimized.
5 MATERIALS HANDLING AND STORAGE
(i) The receipt, handling and storage of powdered raw materials shall be carried out in such a manner as to minimise the emission of dust to the point where there is no significant visible emission. Covered storage shall be provided.
(ii) Gaseous sulphur trioxide shall be kept in a closed system and escapes to air shall be prevented. (iii) If oleum is produced, storage and tanker-loading facilities shall be fitted with means to prevent the
emission of fumes.
6 CHIMNEYS
(i) Chimneys are an insurance policy against plant breakdown and are determined on the basis of the expected maximum rate of sulphur dioxide emission.
(ii) The minimum height for a sulphuric acid plant shall be as follows:
Plant Rated Capacity Height
Up to 400 tonnes/day 60 meters
600 “ 75 “
800 “ 85 “
1000 “ 95 “
(iii) The height may need to be increased to allow for special local circumstances. (iv) The linear velocity of waste gases in the chimney shall not exceed 9m/s.
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
ENVIRONMENTAL GUIDELINE No.6
LEAD WORKS
1 INTRODUCTION
These notes apply to:
a. works in which compounds of lead are produced by the application of heat:
i. lead is extracted or recovered from any material containing lead or its compounds; or ii. lead is refined; or
iii lead is applied as a surface coating to other metals by spraying; or
b. works in which compounds of lead are manufactured, extracted, recovered or used in processes which give rise to dust or fume.
2 SAMPLING AND MEASUREMENT OF EMISSIONS AND MONITORING
(i) As part of proper supervision, the owner shall make inspections of the process and tests of the chimney emissions at least once per week for each exit. Where effective continuous monitors are fitted, less frequent manual tests shall be carried out, with the agreement of the Authority, to check the performance of the monitors. The results of all tests shall be recorded for examination by the Authority.
(ii) Fugitive emissions shall be assessed visibly by the company’s control staff on a daily basis.
3 EMISSION LIMITS AND CONTROLS
(i) The permitted limit for the mass rate of emission of lead is based on the aggregate volume of emission from all lead processes on the site, including emissions from secondary collection systems.
(ii) Each emission to air shall not exceed 5 mg/m3 of lead.
(iii) Where lead-containing fumes or dusts are collected by secondary extraction, installed to prevent fumes entering the working atmosphere, they shall be passed through filters before discharging to air and the concentration of lead in each emission shall not exceed 5 mg/m3.
(iv) The concentration of total particulates in emissions to air shall not exceed 150 mg/m3.
4 MATERIALS HANDLING AND STORAGE
(i) Dusty materials shall be delivered to the works in a manner which prevents their escaping into the external environment, e.g. wetted, in closed containers, or sheeted wagons. The same applies to the transport of dusty materials within the works.
(ii) a. Dusty materials shall be stored and handled under cover where practicable, preferably wetted. For outside storage of dusty materials, enclosed bays shall be provided with walls sufficiently high to prevent wind whipping, and water sprays shall be installed where applicable.
b. Where materials contain compounds which could emit noxious or offensive substances (such as arsine or stibine) when in contact with water, they shall be stored under dry conditions in clearly marked bays or containers.
(iii) The handling and transfer of collected fine dusts from dry arrestment plant shall be carried out by methods which do not give rise to dust emission.
a. Preferred practices include:
i) recycling within the process by means of a directly connected closed handling system.
ii) conversion into a non-dusty form by feeding into a continuous fusion furnace.
iii) discharging directly from the arrestment plant into bags or drums in an enclosed filling booth extracted to a filter.
iv) direct filling into containers which can be charged unopened into furnaces.
b. Another option is the wet pelletising of dust, but this requires careful control to produce a stable pellet which will not break down again.
(iv) The transfer of dusty materials to storage and the recovery of materials from storage shall be carried out by methods which minimize dust emissions. Preferred practices for materials reclamation and transport within the works include:
a. transport of materials from stockpiles to process by fully enclosed mechanical conveying systems, with enclosed transfer points, and not by vehicles.
b. chutes or conveyors discharging onto stockpiles shall be equipped with fixed water sprays. c. conveyor discharge points shall be arranged to minimize the height of fall onto the stockpile or
hopper.
d. for reclamation from stockpiles, an overhead grab crane is preferred to front end loaders. e. all conveyors external to buildings shall be enclosed.
(v) Storage silos for fine materials shall be enclosed and vented to air through filters.
5 OPERATIONAL CONTROLS
All sources of lead fume and dust emissions from the process, such as charging points, slag and metal pouring points, shall be closely hooded and adequately draughted to filters.
Preferred practices include:
a. the provision of lock chambers, where furnaces are top charged.
b. the use of covered launders and ladles for slag and metal tapping, together with close hooding of the tapping points.
c. the hooding of facilities for removing hot drosses from refining or melting furnaces, extended to include the dross receptacles.
d. effective local extraction, or almost complete enclosure, of rotary furnaces to contain combustion gases and fume escape from charging and tapping operations.
6 GENERAL OPERATIONS
(i) The highest standards of housekeeping shall be achieved throughout the works.
(ii) Roadways and other areas where there is regular movement of vehicles shall be hard-surfaced and kept clean, preferably by a machine which combines sweeping, vacuum suction and wetting.
(iii) Measures shall be taken to control dust arising from works traffic, preferably as follows: a. preclude the access of private vehicles to the works area.
b. restrict works operating vehicles to designated functions and do not allow such vehicles onto public roads.
c. use one-way systems for delivery or collection vehicles entering or leaving works. d. a single exit route for vehicles to the site.
(iv) Adequate vehicle washing facilities shall be provided and used to prevent transport of dust outside the works. Particular attention shall be given to the cleaning of vehicle wheels.
7 CHIMNEYS
(i) Chimney heights for lead works shall be determined by the Authority after discussions with works management. As a first assessment the formula He = 2 x M1/2 shall be used, where He is the effective
chimney height in meters, and M is the total site lead emission in g/hr calculated at the emission limits specified in above paragraphs. The chimney heights so obtained may need to be adjusted to allow for thermal buoyancy and local circumstances such as topography, nearby buildings and other nearby emissions.
(ii) The minimum chimney height for lead works shall normally be 30m, but in the case of small scale processes, or works with dual arrestment systems the minimum chimney height shall be 3m above the ridge of the attached or adjacent building.
(iii) In order to obtain maximum advantage from thermal buoyancy, it is recommended that hot emissions take place from the practicable minimum number of chimneys.
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
ENVIRONMENTAL GUIDELINE No.7
MINERAL WORKS
1 INTRODUCTION
(i) These notes apply to works in which min erals, metallurgical slags, or pulverised fuel ash are subjected to any size reduction, grading or heating by processes giving rise to dust or fume, including the subsequent handling of the products of such process. The crushing, screening, drying and coating of materials for use as roadstone, etc. fall within this definition, whether fixed or mobile.
(ii) The concentration of particulates in emissions to air shall not exceed 150 mg/m3.
(iii) Emissions shall be maintained free from visible smoke during the normal operations and substantially free from persistent mist or fume (excluding steam).
(iv) The emissions from any chimney or final outlet shall be free from droplets. (v) Fugitive emissions shall be substantially free from visible emissions of dust.
2 GENERAL OPERATIONS
A Arrestment Plant
High efficiency scrubbing or bag filters, or their equivalent, are appropriate methods of arrestment capable of meeting the emissions limits.
B Materials processing, handling and storage.
In general and where practicable a policy of dust containment is preferred. In some cases suppression techniques, where properly designed, used and maintained, can be an effective alternative and may be the preferred method for some operations.
C Crushers
Crushing plant shall be fitted, where necessary, with an efficient means for the control of dust emission, including the tipping of raw materials into the hopper and the separation of oversize. It may be necessary to require such dusty operations to be carried out in an enclosed structure ventilated to a filter, or to have an equally effective alternative system.
D Conveyors
i. All exposed belt-type conveyors carrying dusty materials shall be enclosed to such an extent as to prevent the generation of airborne dust, e.g.wind-whipping.
ii. Transfer points shall be enclosed and fitted with flexible seals on inlet and exit. Where dry materials are being handled, transfer points shall be ducted to arrestment plant.
iii. Conveyors shall be fitted with an effective means of cleaning the returning belt. E Surge piles and storage
i. Open surge piles following primary and secondary crushing and screening shall be kept to a minimum and the height of free fall of stone similarly minimized, incorporating dust suppression treatment.
ii. Loading to and from stockpile shall be carried out by methods which minimize dust emission and the stockpile should be wetted before being disturbed.
iii. Storage silos for fine materials shall be enclosed and vented to air through filters. F Transport/loading
i. Tankers carrying dusty non-waste material shall discharge only into vessels fitted with an effective dust collecting system.
ii. Road transport of dusty materials shall be carried out in closed tankers or sheeted vehicles. iii. Loading of road vehicles or ships shall be carried out in a manner to minimize airborne dust. iv. Waste dust shall be transported, disposed of or stored in a manner which prevents the emission
of dust.
3 CHIMNEYS
Chimney heights for roadstone plants shall be determined by the Authority after consideration of all the relevant information on throughput, type of material, type and rate of fuel usage, etc.
4 GENERAL
A high standard of housekeeping shall be maintained and all roadways and working areas in regular use shall be hard surfaced and kept clean.
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
ENVIRONMENTAL GUIDELINE No.8
IRON AND STEEL WORKS - FOUNDRIES
1 INTRODUCTION
These notes apply to works where iron or steel are melted, refined and cast, and they cover the associated processes. Melting is usually carried out in cupolas, electric arc furnaces, induction furnaces, and similar small furnaces.
2 SAMPLING, MEASUREMENT OF EMISSIONS AND MONITORING
(i) As part of proper supervision, the owner shall make tests and inspections of the process. The frequency of testing shall normally be not less than once per year, but more frequent tests may be necessary in special circumstances. The results of all tests and inspections shall be recorded and made available to the Authority’s representatives.
(ii) Visual inspections shall be made of fugitive emissions which cannot be measured.
3 EMISSION LIMITS AND CONTROLS
A Cupola Furnaces
During normal operation and blow-down all the cupola gases shall be contained and burnt before discharge to air through a suitable dust arrestor. The final discharge to air shall be virtually invisible as judged by the naked eye and shall contain not more than 150 mg/m3 of total particulate matter.
B Electric Arc Furnaces
i. Primary collection and arrestment are required on all new furnaces and the final emission to air shall contain not more than 150 mg/m3 of particulate matter.
ii. For large furnaces over 20 tonnes capacity, secondary collection shall be used to remove all fume from tapping, refining, charging, etc. and the emission from the arrestment plant shall contain not more than 150 mg/m3 of particulate matter.
iii. Where associated processes give rise to particulate emissions, collection and arrestment are normally required and the concentration of particulate emissions to atmosphere shall not exceed 150 mg/m3.
iv. The emission from any chimney or other final outlet shall be free from liquid droplets. C Induction Furnaces
i. Induction Furnaces normally melt relatively clean scrap and discharge waste gases into the factory atmosphere and thence to air through roof ventilators. The final discharge shall not exceed 150 mg/ m3.
ii. When dirty and greasy scrap is being melted, it shall either be pre-cleaned, or the furnace shall be hooded and the waste gases must pass through suitable treatment plant to give an emission which is virtually invisible as judged with the naked eye.
PCFC-EG#8 Page 1 of 2 Revised:23/04/03
i. Scrap metal usually contains small quantities of non-ferrous metals such as lead and zinc and where this is so the limits for emissions of the non-ferrous metals industries apply, e.g. lead to be less than 0.005 g/m3 and Iron 0.1g/m3. Total heavy metals concentration not to exceed 5 mg/
m3.
ii. There are many processes associated with foundry work which give rise to particulate emissions and these shall be treated suitably to render them harmless and inoffensive. Where shot blasting is carried out the process shall be extracted to a filter to give an invisible emission.
iii. Fugitive dust emissions shall have no significant visible emission as judged by the naked eye.
4 OPERATIONAL CONTROLS
(i) In general, finely divided materials associated with or arising from the process, shall be controlled in such a manner as to minimize emissions to atmosphere.
(ii) Stocks of fine materials (e.g. fluxes, additives, etc) shall normally be delivered and stored under cover to prevent wind-whipping. Loading to and from stock shall be carried out so as to minimize airborne dust.
(iii) Storage silos for fine materials shall be enclosed and vented to air through a filter. (iv) Slag shall be handled and disposed of in a manner which minimizes dust generation.
5 CHIMNEYS
(i) Waste cupola gases shall be vented to air from chimney heights based on the table below, but shall be not less than 6 metres above the cupola structure or adjacent buildings.
Cupola Capacity, TPH Chimney Height, m.
7 or below 21
10 23
15 26
20 28
25 30
(ii) The heights of chimneys for emissions shall be decided by the Authority after discussions with works managements, taking into account local circumstances and nearby buildings. The minimum height shall not be less than 3m above any tallest building to which it is attached or adjacent.
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
ENVIRONMENTAL GUIDELINE No.9
SECONDARY ALUMINIUM WORKS
1 INTRODUCTION
(i) These notes apply to works in which:
a. Aluminum swarf is degreased by the application of heat; or
b. Aluminum or aluminum alloys are recovered from aluminum or aluminum scrap fabricated metal, swarf, skimmings, drosses or other residues by melting; or c. aluminum is recovered from slag; or
d. molten aluminum or aluminum alloys are treated by any process involving the evolution of chlorine or its compounds;
The materials used in above processes or the products are treated or handled by methods which cause noxious or offensive substances to be evolved.
(ii) The notes are intended to provide a basis for consultation between works management and the Authority with flexibility to meet special needs and circumstances.
2 SAMPLING AND MEASUREMENT OF EMISSIONS
(i) As part of proper supervision, the owner shall make tests and inspections of the process. The results of tests and inspections shall be recorded and made available for examination by the Authority representatives. The frequency of testing shall be determined by the Authority after discussions with the works management.
(ii) Tests shall be carried out periodically for emissions of chlorine and hydrogen chloride, where applicable.
3 EMISSION LIMITS AND CONTROLS
(i) The concentration of particulate matter in emissions to air from furnaces using salt as a flux shall not exceed 150 mg/m3. Emissions shall also be substantially free from persistent mist or fume.
(ii) The concentration of particulates in emissions to air from swarf degreasing furnaces shall not exceed 150 mg/m3.
(iii) The concentration of particulates in emissions to air from operations in which dross is treated mechanically for the recovery of metal residues shall not exceed 150 mg/m3. HF/Si F4 not to exceed
20 mg/m3.
(iv) Concentration of chlorine in emissions to air shall be as low as practicable, and in no case shall exceed 10 mg/m3.
(v) Concentrations of hydrogen chloride in emissions to air shall be as low as practicable, and in no case shall exceed 20 mg/m3.
(vi) During normal operation, including charging, emissions shall be maintained substantially free from visible smoke and in any case not more than 150 mg/ m3.
(vii) Where a wet method of gas cleaning is used, the emission from any chimney or final outlet shall be free from liquid droplets.
4 OPERATIONAL CONTROLS
A Treatment of Oily swarf and contaminated scrap
i. Aluminum swarf contaminated with oil-based materials shall not normally be fed to a processing furnace, but shall be treated substantially to remove the oil so as to meet the smoke limit in above paragraph. Alternatively, additional equipment, such as an afterburner, may be installed, effectively to consume smoke emissions from the charging of contaminated swarf.
ii. Charging of contaminated scrap, other than swarf, to furnaces shall be controlled so as to minimize emissions to air.
B Arrestment plant
Because of the corrosive nature of the emissions from most secondary aluminum operations, particular emphasis shall be paid to the selection of suitable materials of construction for ducting, arrestment plant and chimneys.
C Use of chlorine
The storage, handling and use of chlorine shall be carried out with particular care to prevent emissions to atmosphere, preferably to the supplier’s recommendations, and to the satisfaction of the Authority. Safer alternates are recommended for use.
D Use of fluoride fluxes
Procedures for the use of fluoride-containing fluxes shall be agreed with the Authority and additional monitoring may be needed to ensure control of gaseous and particulate fluoride emissions. Each case will be judged on its merits.
E Dross handling and recovery
i. Drosses from the processing furnaces shall be handled and stored in such a manner as to prevent particulate emissions to atmosphere. Drosses shall be cooled in covered containers or tipped for cooling purposes in an enclosed building, with adequate extraction to arrestment plant if necessary in the opinion of the Authority.
ii. Dross recovery operations shall be fully enclosed and extracted to suitable arrestment plant, and the remaining dross residues shall be discharged in a manner which produces no significant visible dust.
iii. Where drosses and other materials contain compounds which emit noxious or offensive gases on the application of heat or contact with water, e.g. arsine or stibine, they shall be stored under dry conditions in clearly marked bays or containers. Procedures for processing such materials shall be agreed with the Authority.
5 CHIMNEYS
(i) Chimney heights for secondary aluminium plants shall be determined by the Authority after discussions with works management.
(ii) The minimum chimney height for any rotary furnace using salt flux shall normally be 37m and for other furnaces shall be 3m above the roof ridge of the building to which it is attached or close by tallest building. The height may need to be increased to allow for local circumstances such as topography, nearby buildings and existing emissions.
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
ENVIRONMENTAL GUIDELINE No.10
CHEMICAL INCINERATION WORKS
1 INTRODUCTION
(i) These notes apply to:
Works for the destruction by burning of:
a. Waste produced from chemical manufacturing processes; or
b. Chemical wastes containing combined bromine, cadmium, chlorine, fluorine, iodine, lead, mercury, nitrogen, phosphorus, sulphur or zinc; or
c. Waste produced in the manufacture of plastics.
(ii) In the context of these notes “works” includes the storage and handling of such wastes at the incineration works prior to incineration, and to the handling of any residues or ashes by methods whereby any noxious or offensive substance may be evolved. Incineration, however, is not considered as safe disposal means of waste gases.
2 SAMPLING AND MEASUREMENT OF EMISSIONS
On incinerators burning a wide variety of wastes, a continuous monitoring and recording instrument shall be installed on the chimney to measure the emission of particulate matter by optical methods.
3 EMISSION LIMITS
(i) All limit values for emission concentrations are expressed as being at the reference conditions of 30oC and a pressure of 1 bar, without correction for water vapour content.
(ii) Emissions shall be maintained free from visible smoke or carbon and in any case not 50 mg/m3,
during normal operation.
(iii) Emissions shall be substantially free from persistent mist or fume, as judged by the naked eye. (iv) Emissions shall be free from droplet fallout.
(v) The concentration of black carbon or particulate matter in emissions to air shall not exceed 50 mg/m3.
(vi) With the exception of Iron, Potassium, Sodium and Calcium, the concentration of any individual metal, or metal compound calculated as metal, shall not exceed 5 mg/m3. The term ‘metal’ shall be
taken to include such elements as Arsenic, Antimony, Selenium, etc. which are also called semi-metals or metalloids.
The following limits will also apply:
Phosphorus compounds, calculated as P 5 mg/m3
Total acidity, calculated as sulphur trioxide 150 mg/m3
Hydrogen chloride 20 mg/m3
Hydrogen fluoride 2 mg/m3
(vii) In addition to the above limits it may be necessary to set limits on other emissions, depending on what is being incinerated. Each case will be considered on its merits. In order to meet the strict emission limits, it may be necessary to restrict the rate of incineration of certain feedstocks.
4 OPERATIONAL CONTROLS
There is a wide variety of types and sizes of incinerators and an equally diverse chemical and physical nature of wastes handled, so it is not possible to lay down requirements which are universally applicable. Each case will be considered on its merits, taking into account the general principles in the following paragraphs.
A Receipt and handling of materials
i. Materials for incineration should normally be tested to determine the appropriate method of storing and means of transfer to the incinerator, and required operating conditions for the incinerator and flue gas treatment plant.
ii. Where materials differing widely in composition are received there should be a comprehensive and well documented system for testing or analysing and for controlling movement of the material through storage and transfer to the incinerator to ensure that it is processed in the correct manner.
iii. All materials for incineration should be handled and stored in suitable equipment and in such a manner as to minimize atmospheric emissions and odours by such practices as closed circuit connections for vapour displacements from liquid transfers, the use of self sealing hose couplings, venting of tanks to vapour control systems, and minimum opening of containers. Account should be taken of any reactions which may take place on mixing of wastes or during storage. Special facilities will be required for handling strongly smelling substances such as mercaptans, amines and acrylates.
iv. There should be appropriate facilities for transferring waste to the incinerator with the minimum emissions of vapour or odour and for controlling the rate of transfer. The requirement shall be considered in relation to the feed systems(s) of the particular incinerator and may include:
a. Pipeline systems for bulk liquids or sludges;
b. Drum handling facilities for liquids, sludges or solids; c. Systems for handling packaged solids;
d. Conveyor or screw feed systems for solids or sludges.
v. Suitable facilities shall be provided to contain and deal with any spillage of materials destined for incineration, arising from operations on the site.
vi. All containers which have been emptied should be disposed of by methods which minimize emissions to atmosphere.
B Design and operation of the incinerator
i. The class of materials to be incinerated, operating conditions of the incinerator and maximum rate of incineration should be agreed between the works management and the Authority. ii. When wastes containing polychlorinated biphenyls (PCBs) are to be incinerated a trial burn
must be carried out to demonstrate that the equipment is capable of achieving a Destruction Efficiency Removal (DRE) of not less than 99.9999%.
iii. Where solids are to be incinerated the feed system and primary combustion chambers must be so designed and operated that charging does not cause an unacceptable rise in chamber pressure, drop in temperature, or oxygen starvation except where starved air incineration is designed for and therefore subject to above paragraph and adequate instrumentation must be installed to ensure this requirement is met.
iv. All liquids and sludges being handled in pumped systems should be injected into the combustion chambers through burner assemblies that are designed to achieve complete combustion.
v. Incinerators will normally be equipped with a separate afterburner/secondary chamber facility. An afterburner must be provided in all cases where starved air combustion in the primary chamber is practiced. Systems where complete combustion can be achieved at all times in the primary chamber with effective control of temperature, residence time and excess oxygen may be allowed to operate without a separate afterburning facility.
vi. The minimum residence time for any chemical incineration process shall be 0.5 seconds. vii. The afterburner chamber shall be designed to produce a high level of turbulence with a
minimum of 3% excess oxygen over that required for complete combustion. Afterburners on incinerators used for the destruction of wastes which could contain chlorinated organic compounds, including phenols, dioxins or related chemical compounds, shall be operated at not less than 1100oC with a residence time of 2 seconds. If the primary combustion chamber
outlet is also maintained at a minimum of 1100oC with not less than 3% oxygen content then the
2 second residence time may refer to the whole system. Less stringent afterburning conditions may be agreed for specific limited ranges of waste material but after burner temperatures of less than 800oC will not normally be permitted.
viii. The suitability of an incinerator for a particular waste and the maximum rate of incineration will depend on such factors as the chemical and physical nature of the waste, achievable temperatures in the combustion chambers, performance of afterburners and flue gas cleaning plant, the chemical nature of gaseous or particulate matter in the flue gas and the height of the chimney.
ix. Where liquid wastes are to be burnt suitable facilities for sampling the liquid(s) in the feed tank, and in the feed line to the burners will be required.
x. Where no scrubber is fitted wastes containing more than 0.1% by weight of halogen should not be burned. Alternatively wastes containing more than 0.1% by weight of chlorine may be incinerated providing that the concentration of hydrogen chloride in the undiluted combustion gases shall not exceed the limit value of paragraph 9 and that the hydrochloric acid gas concentration be continuously monitored.
xi. There shall be an adequate supply of clean support fuel for lighting the incinerator, for bringing the combustion chamber and afterburner up to the required temperatures, and for maintaining these conditions during operation. Clean liquid support fuel shall only be stored in dedicated tanks and its specification agreed.
xii. The incinerator and associated control systems shall be designed so that the plant can be shut down safely, without any significant increase in emission, in the event of a failure of the electricity supply. Requirements may include the provision of stand-by power supplies to enable the plant to continue operating or be shut down safely.
xiii. Removal from the incinerator of ash, burned-out drums or containers should be effected in a manner which minimises the emission of smoke, dust or odour. Where facilities for quenching ash or burned-out containers need to be provided the operation should be ventilated to an appropriate point on the incinerator. Removal of ash or drums shall only be effected when incineration is complete.
C Flue gas treatment
i. The design and method of operation of any flue gas treatment equipment will be specified and agreed according to the type and quantity of materials to be incinerated. Incinerators handling a wide range of chemical wastes will normally require flue gas treatment systems to deal with both gaseous and particulate matter.
ii. Where wet arrestment is used the plant shall be designed and operated to achieve a substantially invisible plume for not less than 95% of operating hours.
iii. Where wet scrubbing plant is to be used the liquid supply should be free from contaminants which could give rise to the emission of noxious or offensive substances. Liquid circulation should be monitored by suitable instruments, such as pH meters and flow meters, to give continuous indication of operating conditions, and interlocks between these and waste feed may be required. Incineration shall not commence until it has been ascertained that the absorption capacity of the liquid is sufficient adequately to scrub all the combustion gases expected to arise during the proposed period of incineration.
iv. Where high energy wet scrubbers are used there shall be continuous recording of the differential pressure across the scrubbing section.
v. Wet arrestment systems should be provided with effective droplet elimination to prevent carry-over of liquid droplets into the exhaust gas stream.
vi. Where dry collection systems are used, the particulate matter collected should be handled in a manner which prevents emission of dust.
D Monitoring and automatic control systems
i. The primary combustion chamber and afterburner chamber shall be fitted with temperature recorders and alarms. Oxygen and carbon monoxide monitors shall also be fitted where practicable to indicate that satisfactory combustion conditions are being attained.
ii. The control systems of the incinerators shall be fitted with interlocks to prevent the introduction of waste, when combustion conditions are such that adequate thermal destruction would not be achieved.
iii. Instrumentation shall be fitted, where practicable, to measure and record the concentration of total dust in the exhaust gases. The use of data logging equipment will be considered.
iv. When organochlorine compounds are being burned samples of the exhaust gases shall be taken continuously and analyzed to an agreed schedule for agreed “marker” compounds which demonstrate the effectiveness of destruction. At least quarterly samples shall be analyzed for the presence of dioxins and dibenzofurans.
5 CHIMNEYS
(i) Chimney heights for chemical incineration works shall be determined by the Authority after discussions with the works management. The first assessment will be based on the maximum mass emission rate of the most significant pollutants, such as sulphur dioxide or others above in paragraphs calculated at the limiting values as appropriate.
(ii) The chimney height so obtained may need to be increased to allow for local circumstances such as topography, nearby buildings and existing emissions.
(iii) The minimum chimney height for any chemical incineration works shall normally be 40m, but this may be modified by the Authority depending on the scale of the operation and the type of material being burnt.
(iv) Chimneys or vents shall normally be designed for an efflux velocity of not less than 15m/sec at full load operation. Caps or cowls will not be permitted. Care should be taken to avoid generating positive pressure zones within the chimney unless the wall is impervious or suitably lined.
(v) All new chimneys shall be designed and insulated to minimize the cooling of waste gases and condensation on internal surfaces. This is particularly important for acidic gases.
6 GENERAL OPERATIONS
(i) All roads, storages and operating areas shall be hard surfaced with facilities for washing spillages and contamination into sumps for recovery or treatment to render them harmless and inoffensive. (ii) A high standard of housekeeping shall be maintained with particular attention being given to
chemical waste storage areas. This shall include regular inspection of drums awaiting treatment, adequate facilities for dealing with suspect drums or containers, satisfactory means of decontamination of containers not being themselves incinerated, methods of preventing spillages entering the environment.
(iii) There should be provision of suitable cleaning substances and/or inert adsorbents to deal with spillages.
For more information please contact Environment, Health and Safety – Free Zone
(EHS-FZ) Department on Tel# 8040275, Fax # 8817023 or P.O.Box17000, Dubai.
ENVIRONMENTAL GUIDELINE No.11
CEMENT WORKS
1 INTRODUCTION
These notes apply to works in which: a. cement clinker is produced; or
b. cement clinker is handled and ground; or
c. ground cement is packed, or loaded into vehicles in bulk.
The definition above includes the handling, storing and processing of raw materials used in cement works.
2 SAMPLING, MEASUREMENT OF EMISSIONS AND MONITORING
(i) As part of proper supervision, the owner shall make tests and inspections of the process to ensure that the equipment is achieving the required results. The results of tests and inspections shall be recorded for examination by the Authority’s representatives.
(ii) Emissions of particulate matter from kilns and clinker coolers, and any other outlet considered by the Authority to be significant, shall be continuously monitored, preferably by optical density measurement.
(iii) Check tests shall be carried out at least once every six months on chimney emissions monitored continuously, to ensure that the calibration has not changed.
3 EMISSION LIMITS AND CONTROLS
(i) The concentration of particulate matter in emissions to the air from kiln waste gases shall not exceed 50 mg/m3, in normal operation.
(ii) The concentration of particulate matter in emissions to air from all other contained sources shall not exceed 50 mg/m3, in normal operation.
(iii) The concentration of hydrogen sulphide in kiln exhaust gases shall normally be absent and in any case shall not exceed 5 ppm (v/v).
(iv) The oxygen content of the kiln waste gases shall be controlled so as not to fall below 1.5% oxygen. (v) The kiln waste gases shall be maintained free from visible smoke and in any case not more than 50
mg/ m3.
(vi) Fugitive dust from miscellaneous operations shall be substantially free from visible emissions as judged with the naked eye.
4 MISCELLANEOUS CEMENT WORKS OPERATIONS
(i) Roads and operating areas shall not be of interlock bricks but be hard surfaced and kept clean, and a high standard of housekeeping shall be maintained throughout the works.
PCFC-EG#11 Page 1 of 2 Revised:23/04/03
(ii) Operations such as clinker cooling, grinding, handling and storage, and cement packing, bulk loading and storage, shall be fitted with filters to prevent emissions of dust. Bulk storage silos shall be vented to air through bag filters.
(iii) Special attention shall be paid to methods of handling if and when clinker has to be stored temporarily in the open in an emergency, in order to minimize dust emissions.
(iv) Miscellaneous non-cement operations such as rock and gypsum crushing, screening, storage, recovery and handling, which may give rise to appreciable emissions of dust shall be fitted with efficient means of dust extraction and arrestment, or dust suppression.
(v) Conveyors above ground shall be enclosed or fitted with wind-boards to prevent wind-whipping, and where dusty materials are being conveyed shall be enclosed and fitted with dust extraction and filtration equipment at changeover points.
(vi) Collected dust shall be disposed of in a manner which is harmless and inoffensive.
(vii) Vehicle speeds in the works should be limited to 16 km./h and downward pointing exhausts should be discouraged.
(viii) An adequate supply of essential spares should be held and duplicate equipment should be installed whenever practicable and necessary to maintain continuity of operations whilst minimizing emissions to air.
5 CHIMNEYS
(i) The minimum height of a new chimney for kiln waste gases shall be 60m and not less than the heights shown below, as extrapolated for intermediate throughputs.
Clinker Throughput TPH Dry Process (m)
30 60
60 73
90 85
120 94
240 126
(ii) The chimney height so obtained might need to be further adjusted to take care of exceptional local circumstances.
(iii) Chimneys should be adequately insulated to avoid condensation on inner surfaces which may lead to the emission of agglomerates.
