Modeling domestic geographical transfers of toxic substances in WEEE: a case study of spent lead-acid batteries in China
This study models previously unknown domestic geographical transfers of toxic substances in waste electrical and electronic equipment (WEEE) by using the minimum distance and maximum flow (MDMF) algorithm. Using lead scrap as a typical case, the results present a complete picture of domestic geographical transfers in China: (1) the total interprovincial transfer of lead scrap is 996 k tonnes, accounting for 63% of total lead recycled; (2) lead scrap transfers between 4 pairs of provinces are more than 100 k tonnes with an average distance per k tonne of lead scrap transferred of 967 km; and (3) using outdated processing technology, national pollutant emissions of lead, CO2 and SO2 resulting from these transfers can reach 50, 497, and 105 k tonnes, respectively. In addition, if provinces recycle locally generated and imported LAB at a ratio below 1:1, or 50% imported LAB, using the advanced process, emissions can be reduced. The domestic geographical transfer model has the following advantages: (1) it is helpful for the geographic distribution and capacity planning of WEEE recycling plants; and (2) it provides a method that may be less time-consuming in estimating the external quantified environmental responsibility of the WEEE generating provinces.