RESEARCH AND ANALYSIS
Table3 Parameters for waste treatment and net additions to stock Parameter Value Reference Net addition to stock 0.09 (0.06 to0.12) (Cote et al. 2015; IEA 2007; FAO 2010) Fraction of consumption to sewage 0.03 (Cote et al. 2015) Fraction of residual waste to energy recovery 0.12 (OECD 2015) Fraction of residual waste to incineration 0.08 (OECD 2015) distribution of product lifetimes can be flexibly captured using, among others, a Weibull distribution (Mu¨ller et al. 2014). This study uses a Weibull distribution of total annual waste paper outputs in Germany based on the parameters determined by Cote and colleagues (2015) and applies it to global paper and cardboard consumption. The second method follows the FAO (2010) and uses a decay model with a half-life of 2 years for all paper products. For both methods, the net addition to stock in a single year is highly sensitive to variations in annual con- sumption. To deal with this, the global paper and cardboard consumption time series (1961–2012) was approximated with a least squares quadratic regression function. The two methods result in fractions of net additions to stock of 0.06 and 0.09, respectively. A third estimate was taken from the IEA (2007, 264). This report suggests a value of 0.12 to 0.15, but because of the discrepancy with the results from the more advanced estimations, only the lower value of 0.12 is considered. The quantities of residual waste paper per country are cal- culated from FAO (2016) and the parameters for additions to stock and losses to sewage. The parameter for sanitary paper to sewage is set based on the fraction of toilet paper reported for Germany (Cote et al. 2015). It was assumed that all residual waste paper ends up effectively treated as residual municipal solid waste (MSW). The rates of residual MSW going to energy recovery, incineration without energy recovery, and landfill (or other disposal) for 30 of 34 Organization for Economic and
Cooperative Development (OECD) countries and China are taken from OECD (2015). Residual waste paper from the rest of the world is assumed to go to landfill. Paper in sewage sludge is assumed to receive the same treatment as residual waste pa- per with the difference that the non-burned fraction is divided equally between landfill and non-energy recovery such as land application. Industrial Waste The fate of industrial waste generated during pulping is ex- trapolated from industry sustainability reports and annual re- ports. Table 4 summarizes the data from four of the largest paper companies in the world, covering 11% of global paper and card- board production. It shows total paper production per company and the reported amounts of waste landfilled or used for non- energy recovery. Some of these quantities were calculated from reported waste treatment per tonne of final product or treatment as a percentage of total waste generation. Non-energy recovery includes land application or composting of sludge. Waste used for energy recovery is not directly reported by most companies, but follows from the difference between pulping losses and the amounts of waste landfilled and used for non-energy recovery. Monte and colleagues (2009) list many pretreatments for en- ergy recovery, but company reports tend not to differentiate such pretreatments. The representativeness of the data is compromised by a se- lection bias—reporting is voluntary and the worst perform- ers naturally stay silent—but the sample does feature good geographical coverage. Data reported by UPM, Stora Enso, Resolute FP, and SCA were excluded as these companies also produce significant amounts of timber. Small fractions of waste dealt with by third parties are allocated to non-energy recovery. Incineration without energy recovery is considered negligible. It is assumed that, on average, the companies produce as much pulp as needed for their own paper and cardboard production and thus reflect the global average for pulping waste per unit of final product. The figures reveal significant differences in perfor- mance between the different companies. On average, 0.06 (0.04 to 0.12) tonne/tonne of paper and cardboard production goes to non-energy recovery and 0.06 (0.04 to 0.11) tonne/tonne goes to landfill.
Table 4 Paper production and industrial waste flows as reported by major paper producers
Industrial waste treatment (megatonnes)
Paper production (megatonnes)
Company
Country
Landfill
Non-energy recovery
International Paper
United States
23.8
1.5 0.3 0.6 0.3
0.9 0.7 0.5 0.6
APP
Indonesia
8.3
5.4 a
Sappi
South Africa United States
Kimberly Clark
4.8
Total
42.2
2.6
2.7
a Based on reported capacity and assumed 90% capacity utilization.
4
Journal of Industrial Ecology
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