Life cycle inventory of the automotive paint processes

JCT CoatingsTech, June, 2008 by Lindita Prendi, Edwin K.L. Tam

Table 6--Solid Emissions

Emissions                                     /1000 [m.sub.2]
                                                Painted BIW

Sludge to landfill (NPRI reportable  
non-reportable) 828

Sludge to landfill (NPRI reportable)

  Glycol Ethers                                     0.07

  Mn compounds                                     83

  Zn compounds                                      0.07

  Phosphorus                                        0.33

  1-Methoxy-2-propanol                              0.02

  Glycol ethers                                     0.08

Total reportable compounds to land (sludge)        83

Filters to landfill (NPRI reportable)

  (a) Mn compounds                                  2.84

  (b) Zn compounds                                  9.11

  (c) Phosphorus                                    0.05

Total reportable compounds to land (filters)       12

Non-Reportable Metals Emissions

  Copper compounds                                 46

Finally, the NPRI reporting is restricted to regulated compounds present as sludge (i.e., reportables); however, total sludge produced typically exceeds the reportable portion. For the pretreatment sub-module, additional data was obtained for the key phosphating unit process from shipping manifest tracking sheets used to transport the sludge to offsite treatment and disposal. However, the shipping manifest data used an average of the 1999 and 2000 calendar years; the older datasets were used because reporting practices at the selected assembly plant changed as of the 2001 calendar year and sludge shipments are no longer monitored by environmental specialist personnel. The pretreatment phosphating non-reportable sludge is included in the emissions inventory only to demonstrate the typical magnitude of difference between reportable and non-reportable sludge emissions.

Additionally for the pretreatment module, a walk-through audit of containers was completed to identify waste containers typically used at the assembly plant for the storage and transport of process materials.

CONCLUSIONS AND RECOMMENDATIONS

Completing Future Manufacturing LCIs

Standard LCI protocols are largely product-based and may need to be adapted for successful completion of LCIs for manufacturing, which is process-based.

Challenges in completing a manufacturing LCI primarily involve data collection. This includes potential lengthy time allowances for establishing appropriate contacts and securing access to internal and confidential data. Further, a manufacturing facility's existing data measurement and reporting is unlikely to be at a resolution corresponding to the scoped LCI system boundaries, thus requiring engineering estimates to apportion data.

Due to limitations in available/measured data resolution and time and resource demands of stage-by-stage, the effort to develop high resolution LCI process flow maps outweighs their benefits to the LCI process with respect to data collection. A lower resolution LCI process flow map should instead be constructed, achieved by placing the system boundary around the LCI sub-module in consideration and aggregating the material/energy/emissions flows within the sub-module boundary.