SPERC fact sheet. Industrial use of coatings in installations with wet scrubber for collection of overspray

Transcription

1 SPERC fact sheet Industrial use of coatings in installations with wet scrubber for collection of overspray Section SPERC Title SPERC code Content Industrial use of liquid spray coatings in installations with wet scrubber for collection of overspray ACEA SPERC 4.1.a.v4 Application of liquid solvent-borne spray coatings, volatile lead substance with water solubility > 10 mg/l ACEA SPERC Application of liquid solvent-borne spray coatings, volatile lead substance with water solubility < 10 mg/l ACEA SPERC 4.1.c.v4 Application of liquid water-borne spray coatings, volatile lead substance with water solubility > 10 mg/l ACEA SPERC 5.1.a.v4 Application of liquid spray coatings, non-volatile lead substance with water solubility <100 mg/l ACEA SPERC 5.1.b.v4 Application of liquid spray coatings, non-volatile lead substance with water solubility < 10 mg/l Scope Covers the process of manual or automatic application of liquid spray coatings in case of transfer of compounds to a process waste water stream due to the use of wet scrubbers for collection of overspray. This includes paint loss due to colour change operations and small amounts of typical purging and rinsing liquids when the major part of purging liquids is collected separately and not transferred into the wet scrubber. The SPERCs are relevant for operations which are linked to a system for separation of paint sludge and water for recirculation and an industrial physico-chemical waste water treatment plant with discharge of pretreated wastewater to a municipal sewage treatment plant. The SPERCs cover large, medium and small operations with usage of aquatically hazardous substances (R 50 to R53, H400 to H413) up to 1,000 kg/d (volatile and/or non-volatile). Typical substance transfer rates have been investigated for large operations, but can be extrapolated to medium and small operations. Professional use (e.g. refinish body-shops) is included as far as small operations work in close-to-industry settings and substance transfer to wet scrubber occurs. Substance Domain: All (see Narrative Description)

2 Related use descriptors Main User Group: SU 3 Sector of Use: SU5, SU6a, SU6b, SU7, SU11, SU 12, SU13, SU15, SU16, SU17, SU18, SU19, SU22, SU24 Environmental Release Class: ERC4, ERC5 Process Categories: PROC7, PROC11 Product categories: PC9a, PC9b Operational conditions Operational conditions Phrases Applies for solvents and other volatile organic compounds which do not become part of coated objects; release to air in compliance with directive 2010/75/EC and its national transpositions no applicable standard phrases ACEA 5.1.a.v4 ACEA 5.1.b.v4 Applies for liquid and solid compounds which are meant to form a durable solid coating on objects; due to the characteristics of spray atomization, a part (10 to 70 %) of these compounds is not deposited on objects, but forms so-called overspray; release to air restricted by directive 2010/75/EC, its national transpositions and further applicable regulations (typically to 3 to 5 mg/m³) no applicable standard phrases ACEA 5.1.a.v4 ACEA 5.1.b.v4 Operational conditions - Free text background Large installations may use up to 1,000 kg/d of volatile compounds with aquatic toxicity (e.g. aromatic hydrocarbons, terpenes, high-boiling alcohols) in application of coatings. Overspray may be collected by a wet scrubber (Venturi or similar, actually wet scrubbers are more and more replaced by dry systems for collection of overspray). Volatile compounds are only retained at low levels in circulating water, as huge air volumes and water movement lead to a relatively low equilibrium stage, far below theoretical dissolution levels of solvents (typically < 0.1 % for solvent-borne coatings, < 0.5 % for water-borne coatings, measured as COD < 2,000 mg/l resp. < 10,000 mg/l). Circulating water is continuously separated from paint sludge but has to be replaced typically once per year due to increase of salt content and activity of microorganisms. Finally, dissolved solvents are transferred into a process waste water stream for further treatment on-site or off-site. Only few installations provide biological treatment for the dissolved organic content in waste water. In order to avoid overload of biological treatment plants, exchanged water from wet scrubbers is typically transferred into a buffer tank from which it can be released at appropriate amounts (e.g. 10 m³/d) for a longer period (between 3 and 100 days). Large installations may use up to 1,000 kg/d of non-volatile compounds with aquatic toxicity (e.g. zinc phosphate, catalysts, UV absorbers) in application of coatings. State of the art application technology limits overspray and purge loss to maximum 40 % for automotive OEM resp. 70 % for automotive parts and smaller industrial objects. Overspray may be collected by

3 Obligatory onsite RMMs a wet scrubber (Venturi or similar, actually wet scrubbers are more and more replaced by dry systems for collection of overspray), which allows to continuously extract minimum 95 % of all non-volatile compounds as paint sludge. Non-volatile compounds may be dissolved in circulating water. However due to their inclusion into the polymer matrix, measured values are ten times lower than theoretical dissolution levels (e.g. < 10 mg/l for zinc compounds with theoretical solubility around 100 mg/l, organic compounds are much more difficult to measure). Circulating water is continuously separated from paint sludge but has to be replaced typically once per year due to increase of salt content and activity of microorganisms. Finally, dissolved compounds are transferred into a process waste water stream for industrial physico-chemical treatment (precipitation, filtration) on-site or off-site. A second step of physico-chemical treatment may occur at municipal sewage treatment plants, however with low impact due to first-hand treatment and dilution. RMM - Phrase RMM-Efficiency (RE SPERC ) ACEA 4.1.a.v4 No RMM for volatile comps., 0 ACEA physico-chemical treatment 0 for non-volatile compounds 0 ACEA 5.1.a.v4 90 ACEA 5.1.b.v4 90 Substance use rate Phrase Value (M SPERC ) ACEA ACEA 4.1.a.v4 Indicative worst case value for the substance use rate per site (M SPERC in kg/d) 11.6 (isotridecanol with actual PNEC surface water of mg/l 1) ) 1,000 (until now no PNEC values provided for aromatic hydrocarbons) ACEA 5.1.a.v4 1,000 (zinc orthophosphate with PNEC surface water of mg/l) Justification M SPERC can be used by the registrant when starting the environmental assessment. M SPERC -represents an indicative worst case value for the substance use rate per site. The M SPERC values have been estimated in dependence of the size of the operation, the number of days emitting, and the concentration of the substance in a finished product (i.e. mixture). See M SPERC -derivation in Appendix. Days emitting Phrase Value (d) ACEA 5.1.a.v4 ACEA 5.1.b.v4 Emission Days (days/year): Emission Days (days/year): 300 for continuous withdrawal 30 (withdrawal from buffer, rate 10 m³/d), (may also be 90 days every three years) 300 for continuous withdrawal 30 (withdrawal from buffer, rate 10 m³/d)

4 Release factors Values (per pathway) To air To water To soil To waste ACEA 4.1.a.v ) ) ACEA ) ) 0.9 2) ) ACEA 5.1.a.v ) ACEA 5.1.b.v ) Justification Releases to air: Volatile compounds are released to air in spray-booths, flash-off zone and drying ovens. Final release to air is depending on required abatement to comply with directive 2010/75/EC (ovens are often connected to abatement which reduces release to air by 5 to 25 for solvent-borne coatings and by 10 to 50 % for water-borne coatings; abatement for spraybooths is only typical for solvent-borne basecoats). Non-volatile compounds are captured in the wet scrubber. Residual emission is typically below 3 mg/m³. 15 kg/h of paint atomized in a spray-booth with 50,000 m³/h exhaust air volume result in 150 g/h residual emission (i.e. 1 %). Releases to water via waste-water: A minor amount of volatile compounds remains in the paint sludge and in the circulating water of the wet scrubber. The content in the water of the wet scrubber depends on a dynamic equilibrium (< 0.1 % for solvent-borne coatings, < 0.5 % for water-borne coatings). Typical solvents for water-borne coatings (alcohols, glycol ethers) have higher water solubility than typical solvents for solvent-borne coatings. Due the different solvent content of coatings, the total transfer rates amount to < 0.5 % for solvent-borne coatings and < 5 % for water-borne coatings. The water volume of the wet scrubber is regularly exchanged at rates between twice per year and once every three years. Exchanged volumes are transferred to a buffer tank and released from there to waste-water treatment plants at typical rates of 10 m³/d. This results in a peak emission for a few days (typically ten-fold for one tenth of all operating days) Releases to soil: Paint sludge and filter sludge is hazardous waste which needs to be incinerated resp. recovered energetically. Inert residues are not used for agricultural purposes. Optional risk management measures Type of RMM Efficiency Industrial biological WWTP 75% Reduced release rates from buffer To be determined

5 Narrative description Scaling Industrial use of liquid spray coatings in installations with wet scrubber for collection of overspray A number of compounds which are used in coatings are assigned to hazards for the aquatic environment and thus have to undergo an assessment of conditions for safe use also when used in mixtures (high-boiling alcohols, aromatic hydrocarbons, terpenes, zinc compounds, catalysts, UV absorbers). As some of these compounds have already been registered under REACH and are assigned to very low PNEC values surface water (e.g mg/l for isotridecanol, mg/l for zinc orthophosphate), a tier 0 assessment would lead to M(safe) volumes which would not match with industrial consumption figures. SPERCs for industrial use of liquid spray coatings in installations with wet scrubber for collection of overspray are based on a calculation model which has been derived from industrial data collection and expert judgment as the relevant substance parameters cannot be measured under real life conditions with reasonable effort. The calculation model is attached. Besides standard scaling algorithms as described hereafter, the model may be widened for substances with higher or lower theoretical solubility in water and for processes with diverging relations between total substance transfer rates and periods with peak releases. Scaling options are based on the comparison of the M Safe SPERC with M Site and changes due to RMM (RE) and/or dilution situation on site (q and G Effluent ). Scalable parameters Parameter description Values SPERC /ES M Safe SPERC, (kg/d) Amount which can be safely used based on the SPERC M Safe outcome of chemical safety assessment RE Total, SPERC Removal efficiency assumed in the SPERC 0 q SPERC Factor by which receiving surface water. dilutes the sewage after treatment 10 G Effluent, SPERC (m 3 /d) Discharge rate of sewage Site-specific parameters M Site, (kg/d) RE Total, Site q Site G Effluent, Site Scaling condition risk driven by wastewater treatment plant microbes [M Safe,SPERC x (1 RE Total, SPERC )] / G Effluent, SPERC [M Site x (1 RE Total, Site )] / G Effluent, Site risk driven by freshwater/freshwater sediments, marine water/marine water sediments [M Safe,SPERC x (1 RE Total, SPERC )] / (G Effluent, SPERC x q SPERC ) [M Site x (1 RE Total, Site )] / (G Effluent, Site x q Site ) Parameter description Values Site Amount which is actually used on-site Removal efficiency realized through RMMs on site Factor by which receiving surface water.dilutes the sewage after treatment Discharge rate of sewage. To be determined by Downstream User

6 Footnotes 1) mg/l is actually communicated as PNEC surface water for isotridecanol. Main manufacturer announced to reconsider this extremely low value by reducing applied safety factors due to better evidence from test results: This will probably lead to higher M(safe) volumes. When isotridecanol is used in coatings, the typical content in mixtures is around 1 %.It is expected that after amendment of the PNEC value, safe use can be demonstrated for reasonable usage volumes. 2) Figures for release to air are worst case figures assuming that volatile compound are not abated. In practice, installations are run in compliance with directive 2010/75/EU and its national transpositions which results in lower release rates. 3) Figures refer to volatile and non-volatile compounds which are bound in paint sludge (hazardous waste for incineration). Figures for the non-volatile compounds (sperc 5.1) express paint overspray rates. Their complement to 1 (between 0.29 to 0.89) refers to transfer efficiency of different spray techniques on different substrates. Appendix: M SPERC -Derivation

7 Considerations for coating spercs Feedback Calculation Input for volatile compounds (consumption) If input figures are at lower end of range, and output figures are at higher end of range, calculated transfer rates are conservative 30 carbodies per hour (most lines have higher capacity) 30 to 60 units per hour 16 hours per day (most lines are operating > 20 h/d) 16 to 24 hours per day 230 days per year 230 to 300 days per year 1.5 kg paint per car sprayed per booth (most figures higher) 1.5 to 5.3 kg per layer 720 kg paint sprayed per booth per day (minimum) 1.5 kg/u x 30 u/h x 16 h/d a. 40 % solvent content (minimum for solventborne) 38 to 75 % 288 kg/d solvent input 720 kd/d x 0.4 b. 12 % solvent content (minimum for waterborne basecoats) 8 (primer) to 18 % 86.4 kg/d solvent input 720 kg/d x 0.12 Output for volatile compounds (via process waste water) If input figures are at lower end of range, and output figures are at higher end of range, calculated transfer rates are conservative Dissolution in water of scrubber to dynamic equilibrium a. 0.1 % solvent content in water at exchange (SB maximum) < 0.1 % b. 0.5 % solvent content in water at exchange (WB maximum) < 0.5 % d. 4 % solvent content in water when purge fluid discharged into scrubber 2.5 to 4% 100 m³ water content in wet scrubber (maximum) 32 to 100 m³ 2 times per year complete exchange (most lines have 1 time or less) 0.33 to 1 time per year a kg/d solvent extraction via scrubber (solventborne) 100 m³/change x 2 changes/a x 0.1 %./. 230 d/a b kg/d solvent extraction via scrubber (waterborbe) 100 m³/change x 2 changes/a x 0.5 %./. 230 d/a 10 m³/d release rate to WWTP/STP after water exchange in wet scrubber 30 m³ in 3 d to 750 m³ in 100 d Scrubber content plus rinsing water is transferred to buffer and released from there Result a. Total solvent output via process waste water is maximum 0.5 % of input for solventborne coatings 0.87 kg/d output./. 288 kg/d input (exact value is 0.3 %) b. Total solvent output via process waste water is maximum 5 % of input for waterborne coatings 4.35 kg/d output./ kg/d input c. Peak release is 10 times higher, but only lasts for one tenth of working days If no on-site biological WWTP is available, the 10 m³ daily peak release volume is diluted into 2,000 m³ default STP volume. d. Purging liquids (water/solvent mixturer or detergents) have to be considered separately in addition Biological treatment assumed off-site by municipal STP only few on-site WWTPs Further reasoning Transfer is measured per parameter COD (0.1 % = 2,000 mg/l COD) Organic substance measurements are difficult at concentrations < 0.1 % In practice, substances are part of azeotropic mixtures Hazardous substances (decanol, heptane, aromatic HC) have low solubility For hazardous substances with solubility below 10 mg/l in solventborne coatings, scaling may be applied by a factor of 10 Input for solid compounds (consumption) 30 carbodies per hour (most lines have higher capacity) 30 to 50 units per hour 16 hours per day (most lines are operating > 20 h/d) 16 to 24 hours per day 230 days per year 230 to 300 days per year 1.5 kg paint per car sprayed (most figures higher) 1.5 to 5.3 kg per layer 720 kg paint sprayed per booth per day (minimum) 1.5 kg/u x 30 u/h x 16 h/d a. 0.5 % content of hazardous and soluble solid compound (e.g. catalyst, stabilizer) 3.6 kg/d critical substance input (not valid for zinc compounds or lead pigments) 720 kd/d x b. 15 % content of hazardous and soluble solid compound (e.g. lead pigment, zinc orthophosphate) 108 kg/d critical substance input (valid for zinc compounds or lead pigments) 720 kd/d x 0.15 Output for solide compounds (via process waste water) 70 % transfer to wet scrubber (maximum overspray plus purge loss) 20 to 70 % a. Typical solubility of catalyst/stabilizer in slightly acidic water 10 mg/l 0.2 to 4 mg/l b. Typical solubility of zinc/lead compounds in slightly acidic water 100 mg/l < 100 mg/l Even lower dissolution rate in water due to polymer inclusion Factor of 10 a. Maximum content of catalyst/stabilizer in water at exchange 1 mg/l b. Maximum content of zinc/lead compound in water at exchange 10 mg/l 100 m³ water content in wet scrubber (maximum) 32 to 100 m³ 2 times per year complete exchange (most lines have less 1) 0.33 to 1 time per year a. 0.9 g/d detectable substance extraction via wet scrubber 100 m³/change x 2 changes/a x %./. 230 d/a b. 8.7 g/d hazardous substance extraction via wet scrubber 100 m³/change x 2 changes/a x %./. 230 d/a 10 m³/d release rate to WWTP/STP after water exchange in wet scrubber 30 m³ in 3 d to 750 m³ in 100 d Scrubber content plus rinsing water is transferred to buffer and released from there Result a. Hazardous solid transfer into process waste water is maximum 0.05 % of input 0.9 g/d output./. 3.6 kg/d input (exact value is %) b. Hazardous solid transfer into process waste water is maximum 0.01 % of input 8.7 g/d output./. 108 kg/d input (exact value is %) c. Peak release is 10 times higher, but only lasts for one tenth of working days If no on-site biological WWTP is available, the 10 m³ daily peak release volume is diluted into 2,000 m³ default STP volume. Physico-chemical treatment (90 % efficiency) assumed by on-site waste water treatment plant Further reasoning Substance measurements are difficult for organic substances, feasible for metals Detectable substance may be portion of hazardous substance (e.g. tin in organotin compounds) Further reduction due to continous extraction via paint sludge removal