Decomposing the Influencing Factors of China’s Industrial Wastewater Discharges Using LMDI I Method

Abstract

China’s industry accounts for 46.8% of the national gross domestic product (GDP) and plays an important strategic role to its economic growth, but it is also the main water pollution sources. In order to identify the relationship between the underlying driving forces and various environmental indicators, two critical industrial wastewater pollutant discharges over 2001-2009, including Chemical Oxygen Demand (COD) and ammonia nitrogen (NH4-N), were decomposed into three factors, i.e., production effect (caused by change in the scale of economic activity), structural effect (caused by change in economic structure) and intensity effect (caused by change in technological level of the sector), using a logarithmic mean Divisia index I (LMDI I) decomposition method. Results showed that: (1) the average annual effect changes of industrial wastewater changes of COD discharges in China is -2.99% with the production effect, structural effect, and intensity effect as 14.64%, -1.39%, and -16.24%, respectively. Similarly, the average effect changes of industrial wastewater changes of NH4-N discharges is -4.03% with production effect, structural effect, and intensity effect as 16.18%, -2.88%, and -17.33%, respectively. (2) production effect was the major factor responsible for the rise of COD and NH4-N discharges, accounting for 45% and 44% of the total contribution. (3) structural effect contributed to the decrease of COD and NH4-N discharges with a small effect of 4% and 8% in total contribution. (4) intensity effect had an dominant decremental effect in COD and NH4-N discharges, accounting for 50% and 48% of the total contribution; intensity effect could be further decomposed in cleaner production effect and pollution abatement effect, and cleaner production effect of COD and NH4-N accounts for 60% and 55% in pollution reduction. (5) the main contributors to incremental COD and NH4-N discharges among industrial sub-sectors were manufacture of paper and paper products, processing of food from agricultural products, manufacture of textile and so on. These sectors should be the top priorities for policy makers to reduce pollutants discharges, and the potential measures are industrial restructuring and related regulation.