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Abstract. The main objective of wastewater treatment plants (WWTPs) is to remove pathogens, nutrients, organics, and other pollutants from wastewater. After these contaminants are partially or fully removed through physical, biological, and/or chemical processes, the treated effluents are discharged into receiving waterbodies. However, since WWTPs cannot remove all contaminants, especially those of emerging concern, they inevitably represent concentrated point sources of residual contaminant loads into surface waters. To understand the severity and extent of the impact of treated-wastewater discharges from such facilities into rivers and lakes, as well as to identify opportunities of improved management, detailed information about WWTPs is required, including (1) their explicit geospatial locations to identify the waterbodies affected and (2) individual plant characteristics such as the population served, flow rate of effluents, and level of treatment of processed wastewater. These characteristics are especially important for contaminant fate models that are designed to assess the distribution of substances that are not typically included in environmental monitoring programs. Although there are several regional datasets that provide information on WWTP locations and characteristics, data are still lacking at a global scale, especially in developing countries. Here we introduce a spatially explicit global database, termed HydroWASTE, containing 58 502 WWTPs and their characteristics. This database was developed by combining national and regional datasets with auxiliary information to derive or complete missing WWTP characteristics, including the number of people served. A high-resolution river network with streamflow estimates was used to georeference WWTP outfall locations and calculate each plant's dilution factor (i.e., the ratio of the natural discharge of the receiving waterbody to the WWTP effluent discharge). The utility of this information was demonstrated in an assessment of the distribution of treated wastewater at a global scale. Results show that 1 200 000 km of the global river network receives wastewater input from upstream WWTPs, of which more than 90 000 km is downstream of WWTPs that offer only primary treatment. Wastewater ratios originating from WWTPs exceed 10 % in over 72 000 km of rivers, mostly in areas of high population densities in Europe, the USA, China, India, and South Africa. In addition, 2533 plants show a dilution factor of less than 10, which represents a common threshold for environmental concern. HydroWASTE can be accessed at https://doi.org/10.6084/m9.figshare.14847786.v1 (Ehalt Macedo et al., 2021).

Green infrastructure (GI) is a land development approach that uses a network of natural and built areas and waterways to create healthier urban environments. This study presents a synthesis of GI planning and adoption in 16 cities selected from around the world; 12 of these cities are located in the United States. The study highlights key socio-economic benefits associated with GI adoption and documents analytical procedures used to quantify the benefits linked to GI implementation. The benefits as identified and reported in this study are qualitative rather than quantitative.

Abstract. The main objective of wastewater treatment plants (WWTPs) is to remove contaminants such as pathogens, nutrients, and organic and other pollutants from wastewaters using physical, biological and/or chemical processes prior to discharge into receiving waterbodies. However, since WWTPs cannot remove all contaminants, they inevitably represent concentrated point sources of residual contaminant loads into surface waters. To understand the severity and extent of the impact of wastewater discharges from such facilities into rivers and lakes, as well as to identify opportunities of improved management, detailed information about WWTPs is required, including (1) their explicit geospatial locations to identify the waterbodies affected; and (2) individual plant characteristics such as population served, flow rate of effluents, and level of treatment of processed wastewaters. These characteristics are especially important for contaminant fate models that are designed to assess the distribution of substances that are not typically included in environmental monitoring programs, such as contaminants of emerging concern. Although there are several regional datasets that provide information on WWTP locations and characteristics, data are still lacking at a global scale, especially in developing countries. Here we introduce HydroWASTE, a location-explicit global database of 58,502 WWTPs and their characteristics. This database was developed by combining national and regional datasets with auxiliary information to derive or complete missing WWTP characteristics, including the amount of people served. A high-resolution river network with streamflow estimates was used to georeference WWTP outfall locations and calculate each plant’s dilution factor (i.e., the ratio of the natural discharge of the receiving waterbody to the WWTP effluent discharge). The utility of this information was demonstrated in an assessment of the distribution of wastewaters at a global scale. Results show that 1.2 million kilometers of the global river network receive wastewater input from upstream WWTPs, of which more than 90,000 km are downstream of WWTPs that offer only primary treatment. Wastewater ratios originating from WWTPs exceed 10 % in over 72,000 km of rivers, mostly in areas of high population densities in Europe, USA, China, India, and South Africa. In addition, 2,533 plants show a dilution factor of less than 10, which represents a common threshold for environmental concern.

S1 National and regional wastewater treatment plant (WWTP) datasets S1.1 EuropeThe Urban Waste Water Treatment Directive (UWWTD; https://uwwtd.eu/) is concerned with the collection, organisation and management of data related to the treatment and discharge of urban wastewater. Version 6 of their WWTP database from 2017 contains 30,437 records from which we used 24,971. The excluded records were collection facilities (not connected to a discharge point) or records without point coordinates. The UWWTD database provides information on effluent load in terms of population equivalent and treatment level. In version 8 from 2020, wastewater discharge was included for 8,662 WWTPs. The countries included are: Austria,