To provide additional guidance to facility operators, the Technical Advisory Committee (TAC) prepared a "Code of Good Housekeeping" as a brief outline of what should be considered to ensure that environmental releases of Ozone Depleting Substances (ODS) through all media are minimized. This Code is also intended to provide a framework of practices and measures that should be adopted at facilities undertaking the destruction of ODS.
Not all measures will be appropriate to all situations and circumstances, and as with any Code, nothing specified should be regarded as a barrier to the adoption of better or more effective measures if these can be identified.
This refers to measures that may be appropriate prior to any delivery of ODS to a facility.
- Facility operator to generate written guidelines on ODS packaging/containment criteria, together with labelling and transportation requirements. These guidelines to be provided to all suppliers/senders of ODS prior to agreement to accept such substances.
- Facility operator to seek to visit and inspect proposed senders stocks and arrangements prior to movement of the first consignment. This is to ensure awareness on the part of the sender of properpractices, and compliance with standards.
This refers to measures to be taken at the time ODS are received at the facility gate.
- Immediate check of documentation prior to admittance to facility site, coupled with preliminaryinspection of the general condition of the consignment.
- Where necessary, special or "fast-track" processing/repackaging facilities may be needed to mitigate risk of leakage/loss of ODS.
- Arrangements should exist to measure gross weight of consignment at the time of delivery.
Unloading from Delivery Vehicle
This refers to measures to be taken at the facility in connection with unloading ODS. It is generally assumed that ODS will normally be delivered in some form of container, drum, or other vessel that is removed from the delivery vehicle in total. Such containers may be returnable.
- All unloading activities should be carried out in properly designated areas, to which restricted personnel access applies.
- Areas should be free of extraneous activities likely to lead to, or increase the risk of, collision, accidental dropping, spillage etc.
- Materials should be paced in designated quarantine areas for subsequent detailed checking and evaluation.
This refers to the arrangements for detailed checking of the consignments of ODS prior to destruction.
- Detailed checking of delivery documentation should be done, along with a complete inventory, to establish that delivery is as advised and appears to comply with expectation.
- Detailed checks of containers should be made both in respect of accuracy of identification labels, etc, and of physical condition and integrity. Arrangements must be in place to permit repackaging or "fast-track" processing of anything identified as defective.
- Sampling and analysis of representative quantities of ODS consignments should be carried out to verify material type and characteristics. All sampling and analysis should be carried out using approved procedures and techniques.
This refers to matters concerning the storage and stock control of ODS.
- ODS materials should be stored in specially designated areas, subject to the regulations of the relevant local authorities.
- Locations of stock items should be identified through a system of control that should also provide a continuous update of quantities and locations as stock is destroyed, and new stock is delivered.
It is important to be aware of the quantities of ODS processed through the destruction equipment. Where possible, flow meters or continuously recording weighing equipment for individual containers should be employed. As a minimum, containers should be weighed "full" and "empty" to establish quantities by difference.
Residual quantities of ODS in containers that can be sealed, and are intended to be returned for further use, shall be allowed. Otherwise, containers shall be purged of residues and/or destroyed as part of the process.
This refers to basic features and requirements of plant, equipment, and services deployed in the facility.
In general, any destruction facility should be properly designed and constructed in accordance with the best standards of engineering and technology, and with particular regard to the need to minimize, if not eliminate, fugitive losses.
- ODS Pumps: Magnetic drive, sealess, or double mechanical seal pumps should be installed to eliminate environmental releases resulting from seal leakages.
- Valves: Valves with reduced leakage potential should be used. These include quarter-turn valves or valves with extended packing glands.
- Tank Vents (including Loading Vents): Filling and breathing discharges from tank/vessels should be recovered or vented to a destruction process.
- Piping Joints: Screwed connections should not be used, and the number of flanged joints should be kept to a minimum that is consistent with safety and the ability to dismantle for maintenance and repair.
- Drainage Systems: Areas of the facility where ODS are stored or handled should be provided with sloped concrete paving and a properly designed collection system. Water that is collected should, if contaminated, be treated prior to authorized discharge.
In general, all maintenance work should be performed according to properly planned programs, and should be executed within the framework of a permit system to ensure proper consideration of all aspects of the work.
ODS should be purged from all vessels, mechanical units, and pipework prior to the opening of these items to the atmosphere. The contaminated purge should be routed to the destruction process, or treated to recover the ODS.
All flanges, seals, gaskets and other sources of minor losses should be checked routinely to identify developing problems before containment is lost. Leaks should be repaired as soon as possible.
Consumable or short-life items, such as flexible hoses and couplings must be monitored closely, and replaced at a frequency that renders the risk of rupture negligible.
All sampling and analytical work connected with ODS, the process, and the monitoring of its overall performance should be subject to quality assessment and quality control measures in line with some recognized practices. This should include at least occasional independent verification and confirmation of data produced by the facility operators.
Consideration should also be given to the adoption of quality management systems and environment quality practices covering the entire facility.
All personnel concerned with the operation of the facility (with "operation" being interpreted in its widest sense) should have training appropriate to their task.
Of particular relevance to the ODS destruction objectives is training in the consequences of unnecessary losses, and training in the use, handling, and maintenance of all equipment in the facility.
All training should be carried out by suitably qualified and experienced personnel, and the details of such training should be maintained in written records. "Refresher" training should be conducted at appropriate intervals.
In the interest of protecting the stratospheric ozone layer, it is essential that used ODS and products containing ODS be collected and moved efficiently to facilities practicing approved destruction technologies. For transportation purposes, used ODS should receive the same hazard classification as the original substances or products. The following proposed code of transportation for ODS from customer to destruction facilities is provided as a guide to help minimize damage caused to the ozone layer as a result of ODS transfers.
It is important to supervise and control all shipments of used ODS, and products containing ODS, according to national and international requirements to protect the environment and human health. To ensure that ODS and products containing ODS do not constitute an unnecessary risk, they must be properly packaged and labelled. Instructions to be followed in the event of danger or accident must accompany each shipment to protect human beings and the environment from any danger that might arise during the operation.
Notification of the following information must be provided at any intermediate stage of the shipment from the place of dispatch until its final destination. When making notification, the notifier shall supply the information requested on the consignment note, with particular regard to:
- The source and composition of the ODS, and products containing ODS, including the customer's identity;
- Arrangements for routing and for insurance against damage to third parties;
Measures to be taken to ensure safe transport and, in particular, compliance by the carrier with the conditions laid down for transport by the member states concerned;
- The identity of the consignee, who should possess an authorized centre with adequate technical capacity for the destruction; and
- The existence of a contractual agreement with the consignee concerning the destruction of ODS and products containing ODS.
This code of transportation does not apply to the disposal of ODS-containing rigid insulation foams. The most appropriate way to dispose of such products may be by incineration in municipal waste incinerators.
Where national standards do not exist, the TAC recommends adoption of the following monitoring guidelines to ensure that destruction processes operating with an approved technology meet the suggested minimum standards contained in this report:
- All sampling and analysis of ODS and other required pollutants, including dioxins and furans, shall be carried out using ISO-standards.
- ISO-standards for reference measurement methods and the calibration of automatic measurement systems shall also be applied.
- Parties may use their own standards after having demonstrated that the results are comparable with results using ISO-standards.
- While awaiting the elaboration of ISO-standards, national standards shall apply.
- If no national or ISO-standards are available corresponding US EPA methods can be used.
Measurement of ODS
Operators of destruction facilities should take all necessary precautions concerning the storage and inventory control ODS containing material received for destruction. Prior to feeding the ODS to the approved destruction process, the following procedures are recommended:
- The mass of the ODS containing material must be determined.
- Representative samples should be taken where appropriate to verify that the concentration of ODS matches the description given on the delivery documentation.
- Samples should be analyzed by an approved method. If no approved methods are available, the adoption of US EPA methods 5030 and 8240 is recommended.
- All records from these mass and ODS concentration measurements must be documented and kept in accordance with ISO 9000 or equivalent.
Operators shall ensure that destruction processes are operated efficiently to ensure complete destruction of ODS to the extent that it is technically feasible for the approved process. This shall include the use of appropriate measurement devices and sampling techniques to monitor the operating parameters, burn conditions, and mass concentrations of the pollutants that are generated by the process.
Gaseous emissions from the process must be monitored and analyzed using appropriate instrumentation. This should be supplemented by regular spot checks using manual stack-sampling methods. Other environmental releases, such as liquid effluents and solid residues, require laboratory analysis on a regular basis.
The continuous monitoring recommended for on-going process control, including off-gas cleaning systems, is as follows:
- Measurement of appropriate reaction and process temperatures.
- Measurement of flue gas temperatures before and after the gas cleaning system.
- Measurement of flue gas concentrations for oxygen and carbon monoxide.
Any additional continuous monitoring requirements are subject to the national regulatory authority that has jurisdiction. The performance of on-line monitors and instrumentation systems must be periodically checked and validated. When measuring detection limits, error values at the 95% confidence level must not exceed 20%.
At no time during the destruction process must the measured pollutants exceed the acceptable minimum standards stated in this report. The approved processes must be equipped with automatic cut-off control systems on the ODS feed system, or be able to go into standby mode whenever:
- The temperature in the reaction chamber is below 8500C.
- The required minimum destruction conditions stated in the performance specifications cannot be maintained.
The ODS destruction efficiency, for a process within an approved facility, as well as for other environmental releases, shall be validated at least once every 3 years. Once a destruction facility has been fully commissioned (new or rebuilt) the process must undergo a complete validation to ensure that all facility characteristics are completely documented and demonstrated to meet UNEP requirements. At least three test runs per condition shall be used to determine the limitation of ODS concentrations in the feed and the optimum facility operating conditions. Only those test runs for the optimum condition need to be reported to the appropriate regulatory body.
Tests shall be done with known feed rates of a given ODS-compound or with well-known ODS mixtures. In cases where a destruction process incinerates halogen containing wastes together with ODS, the total halogen load shall be calculated and controlled. Three tests results, each of at least 6 h duration must be completed.
The destruction efficiency (DE) recommended means that less than 0.1 g of total ODS will enter the environment from flue gas emissions, liquid effluents, and solid residues, when 1000 gram ODS are fed into the process. A detailed analysis of stack test results should be made available to verify emissions of halogen acids and PCDD/PCDF. In addition, a site-specific test protocol should be prepared and made available for inspection by the appropriate regulatory authorities. The sampling protocol shall report the following data from each test:
- ODS feed rate,
- Total halogen load in the waste stream,
- Residence time for ODS above 8500C,
- Oxygen content in flue gas,
- Gas temperature in combustion chamber,
- Flue gas flow rate,
- Carbon monoxide in flue gas,
- ODS content in flue gas,
- Effluent volumes and quantities of solid residues discharged,
- ODS concentrations in the effluent and solid residues, and
- Concentration of PCDD/PCDF, dust, HCl, HF, and HBr in the flue gases.
Source: Extract from the report of the ad-hoc technical advisory committee on ODS destruction technologies, reproduced in the Handbook for the International Treaties for the Protection of the Ozone Layer, Sixth Edition (2003), UNEP Ozone Secretariat, Nairobi, Kenya, ISBN:92-807-2316-2, pg 277-282. Full document available at www.unep.org/ozone.