New insights from grey water footprint assessment: An industrial park level

Abstract

Greywater is found to bring higher water pressure than freshwater consumption, thus grey water footprint (GWF) has received great attention as a comprehensive indicator to assess wastewater pollution. Industrial park is an important source for wastewater discharge, but few GWF studies have been conducted at the industrial park level due to lack of data availability. To fill such a gap, this study develops one GWF assessment model at the industrial park level by considering wastewater sources from enterprises, wastewater treatment plant (WWTP), residents and agriculture. Such a model is then tested in the Changzhou Economic and Technology Development Zone (CETDZ). Results show that non-connected enterprises were the dominant sources for wastewater discharge, particularly in terms of total phosphorus (TP) and NH3–N pollution. The critical pollutants for GWF in CETDZ include total nitrogen and TP, which are mainly from rural towns. The top ten companies for GWF are identified, which can help the local government to prepare more appropriate wastewater control policies. Several mitigation measures, including increasing connection rate of the non-connected enterprises, controlling key enterprises, recycling wastewater from WWTP, and reducing the background concentration of natural water bodies, are investigated, in which increasing connection rate is identified as the most effective one. Finally, several policy recommendations on increasing connection rate, such as implementing river dredging projects and artificial wetland technology, are proposed.