New Approach to Municipal Grey Water Footprint Estimation: A Case Study for Aegean Region Cities in Turkey

Abstract

This study aimed to develop an approach to investigate grey water footprint-GWF of municipalities in the Aegean Region in Turkey. In this scope 8 out of 81 cities were analyzed in terms of their waste water production (volume), waste water treatment (type of treatment, waste water receiving media etc.) in the country. Data was handled, within the series of waste water official surveys at a municipal level published annually/ biannually by the National Institute of Statistics (TUIK) since 2001. "Total Nitrogen TN" has been selected as a reference variable for GWF calculations. The required additional data/information for the calculations was natural/background nitrogen concentrations, maximum allowable nitrogen concentrations for water bodies. Grey water footprint was calculated for each single city and then spatial differences were determined. Study results revealed that GWF was changeable from one city to another (450-1150 m 3 /ca.yr). Higher GWF (treated) amount compared to the GWF (un-treated) in some regions was explained by higher volume of treated wastewater. Observation of relatively high values for GWF (treated) in some places was due to type of water treatment processes. Availability of N removal process at treatment plants was major impact on low GWF value. It can be concluded that GWF could be indicator to investigate effectiveness of wastewater management strategies, and determine its environmental effects.