Types of waste and sources

Transcription

1 Exclusion Specifically excluded are waste finished products in which the chlorinated alkane is an integral part e.g., discarded PVC cable, rubber belting and specialised papers. In these cases CAs are not additive to environmental hazards and normal disposal techniques are acceptable e.g., municipal incineration or landfill, according to local regulation. Such materials are under EU review at present. Types of waste and sources Solids These include accidental spillages of liquid CAs that have been absorbed onto an absorbent powder/ sand/ powder type CP70 that is unusable through contamination or other reasons, dried sludges from user process such as paper coating or swarf from metal cutting operations. Liquids/Semi-liquids These may be further sub-divided into: Oil based Examples include used oils from metal forming/deforming operations, plasticisers collected during the processing of flexible PVC or unusable liquid CA. Water based These could be mixtures or emulsions containing liquid CAs principally from metal forming/deforming but also including used leather textile treatment liquors. Sludges These include mixtures of solids with either oil or water based waste containing CAs e.g. unusable pigment, resin or filler dispersions from paint, sealant and paper. Classification and regulations Waste chlorinated alkanes have been classified by a number of bodies: The 25 th Adaptation to Technical Progress to the Dangerous Substances Directive 67/548/EC has formally classified Short Chain Chlorinated Paraffins C as Category 3 carcinogens (R40), and as Dangerous for the Environment (R50/53). International Maritime Goods Code (IMDG) listing C grades as "severe marine pollutants". Other types are not listed in IMDG so long as the CA does not contain more than 1 % of C products.

2 In Germany C grades are classified in KBwS Water Hazard Class 3 (serious water pollution hazard). Long-chain 70% (solid) types are classified in WGK 1 (slight hazard). Liquid grades from C and long-chain wax are classified WGK 2. The Directive 91/689/EC on hazardous waste specifies ecotoxicity as one of the criteria according to which such wastes should be classified. Therefore, classification as Dangerous to the Environment would mean that waste containing significant quantities of C CAs will almost certainly be regarded as "hazardous waste". At the time of writing, the percentage that would be regarded as "significant" is still unclear, although it is likely that the proposed "Dangerous Preparations Directive" may be used to assess criteria for waste in addition to products. Longer chain (C 14 and above) CAs have much lower aquatic toxicity and solubility than C types. These longer chain products are not classified as Dangerous for the Environment. Nevertheless, the EU has proposed the same R50/53 label as for short-chain chlorinated paraffins despite the fact that they are far less hazardous to the environment. Consequently, waste containing these products would not be termed hazardous under Directive 91/689/EC. See the Directive 91/689/EC page on eur-lex.europa.eu Currently in the USA, under the Federal Resource Conservation Recovery Act (RCRA) system, CAs are not regulated hazardous wastes. Ecotoxicity is among the general properties on the basis of which waste may be classified as hazardous. Therefore C CAs could be classified as hazardous in case of an amendment. The detail of US state regulation is available on request. Disposal of wastes containing chlorinated alkanes There are three possibilities: resource recovery (reuse/ recycling or recovering of energy by incineration) destructive incineration landfill Each type of waste may be safely managed by one or more of these techniques. Recommendations are as follows (local regulations should be consulted to ensure compliance): Solids C liquids adsorbed onto solids - Hazardous waste landfill or Incineration. C 14-17, C 18-20, C solid and liquid CPs absorbed onto non-combustible solids - Landfill. C 14-17, C 18-20, C solid and liquid CPs adsorbed/ absorbed onto combustible solids - Incineration or landfill.

3 Metal swarf with CAs - Incineration/re-smelting or degreasing/separation from solvent or incineration. Oil based liquids Used oil from metal working operations - Recovery (N.B. restrictions in Germany) or incineration. Mixed plasticiser condensates - Recovery/ deodorisation/ re-use when feasible or incineration. Unusable liquid CAs - Incineration. Water based liquids Emulsions and mixtures should first be split into oil and water phases. The oil phase should then be disposed of by incineration. Three techniques can be utilised in the splitting process producing split waste of differing quality. 1. Chemical splitting This gives split water with high salt content and imperfect oil separation meaning that further treatment is required. The oil phase is also contaminated with chemicals, water, etc. and is consequently treated as "hazardous waste". Mineral oils can also be carcinogenic. 2. Aqueous evaporation The water is evaporated and, when condensed, often requires no additional treatment (unless contaminated by volatile substances). The oil phase can be disposed of by normal incineration/energy generation (depending on calorific value). 3. Ultrafiltration The separated water may require some additional treatment e.g. to reduce Chemical Oxygen Demand (COD). The oil phase can be treated as required for "aqueous evaporation". Sludges Three phase mixtures (oil, water and solid) of this type are best disposed of as hazardous waste by a specialist contractor. Alternatively, a combination of the above separation processes may be employed by larger companies with their own facilities.

4 Oil recovery Oil recovery and secondary refining are rightly encouraged (EU Directives such as 75/442/EEC and 87/101/EEC and in the USA via RCRA waste minimisation) and oils containing chlorinated alkanes do not present problems in these processes. Undesirable by-products are not present in or formed from chlorinated alkanes either in metal working operations or recovery. In an attempt to prevent waste PCBs entering oil recovery processes in Germany their government, in the early 1990s, modified the "old oil law" in such a way that it also penalises users of chlorinated alkanes (the limit to halogen content at <0.2% for "old oil" purposes). It is expected that other EU Member States and federal USA will continue to encourage the full and proper re-use of waste oils which include the highly cost-effective CAs. Euro Chlor and the CASG support this. Incineration Studies on the combustion of chlorinated alkanes mixed with either waste solids/ liquids have shown that in full-scale industrial installations it is entirely possible to operate without forming or emitting any dioxins. Excessively high operating temperatures are not required. In fact, in vapour phase studies dioxins were not detected above 700 C. Download the dioxins information sheet document (pdf) A major product of combustion is hydrogen chloride and incineration facilities are designed so that condensation does not occur on metallic surfaces leading to corrosion. Large modern incineration facilities are often fitted with acid scrubbing facilities to remove HCl. Where scrubbing is not available, the incinerator gaseous effluent may be limited to its allowable halogen and other gas contents. CAs containing waste oils are also used in energy generation (cement kilns, direct power etc). In this case, for calorific value purposes and minimisation of HCl formation, it is suggested that the chlorine content of the waste oil be limited to ~1%. Landfill Chlorinated alkanes are not normally disposed of to landfill as liquids, nor are liquids containing chlorinated alkanes put in landfills. Solid wastes containing shorter chain chlorinated alkanes (C ) should be treated as hazardous waste in a landfill context in view of their toxicity to aquatic organisms. Solid wastes containing chlorinated alkanes C 14-17, C or C may be disposed of to landfill. The chlorinated alkane is firmly bound to solids and cannot escape into groundwater at a level

5 above its solubility limit. These CAs are of significantly lower toxicity to aquatic organisms at or below their solubility limit.