The potential for water recovery from urban wastewater - the perspective of urban wastewater treatment plant operators in Denmark

Climate change and freshwater scarcity make water recovery from urban wastewater a key element of circular economy strategies. This article presents the results of a survey conducted in Denmark among urban wastewater treatment plant (WWTP) operators. Although Denmark is not traditionally water-stressed, local pressures and environmental ambitions drive growing interest in water recovery and reuse. The survey was administered to WWTP operators representing approximately 36 % of Denmark’s treatment capacity, focusing on current reuse practices, perceived barriers, and opportunities. Findings reveal that 70 % of operators already reuse treated effluent internally, primarily for equipment cleaning, while most others plan to implement similar steps. Industrial use is identified as the most promising application for external reuse, followed by urban use. However, major barriers include the absence of detailed legal frameworks and concerns of microbiological risks. Despite this, most respondents support the development of national legislation aligned with EU Regulation 2020/741. Operators emphasized the importance of financing based on cost recovery principles and highlighted industry as a key end-user in emerging water symbioses. The results confirm a high level of awareness and interest among Danish WWTP operators in advancing water reuse initiatives, especially within industrial and circular economy contexts. These insights provide a foundation for refining policies, aligning regulations, and investing further in sustainable water reuse infrastructure. • Water recovery from urban wastewater is developing in the Baltic Sea Region, including Denmark. • In external use, Danish operators focus on industry. • Survey results show the interest in water reclamation and reuse by Danish WWTP operators. • Use of wastewater for the treatment plant's internal purposes is very popular. • It is necessary to develop methods of recovering water from wastewater for industrial purposes.