Key partners: Sewer Mining (SM) technology is a mobile wastewater treatment system in containers able to extract wastewater from local sewers, treat it directly and reuse at the point of demand in dense urban environments. The unit consists of a membrane bioreactor unit (MBR) and a UV disinfection component and produces high quality reclaimed water for irrigation and for aquifer recharge during the winter. The SM unit has an annual capacity of about 9.000 m3 of reclaimed water Treatment residuals are collected, treated locally in the site and are transformed to an eco-friendly fertilizer (compost), when merged with green waste from pruning. Implemented technology The technology has been tested for over 1.5 year. Sampling and analysis activities have been implemented at a weekly basis and the main results that are illustrated in the table and the diagrams are summarized below: • SM produces water of a quality that meets all national and international criteria for unrestricted irrigation and urban use • Achieves complete elimination of organic carbon and pathogenic content • Provides reduction of pathogens due to MBR filtration process (without addition of chemicals avoiding production of secondary pollutants) • UV disinfection unit showed great performance • System works automatically and is remotely monitored in terms of operation and quality performance. Parameters Influent Effluent after UV disinfection Legislation Limits TSS 253± 97 ≤ 2 for 80% of samples ≤2 for 80% of samples ≤10 for 80% of samples BOD5 216 ± 64 8,6 ± 2,4 3 ≤10 for 87% of samples ≤10 for 80% of samples COD 695 ± 97 24,2 ± 4,1 3 - TN 81 (average) 5,5 ± 1,4 3 ≤ 15 NH4-N 5 ± 3 0,2 ± 0,19 3 ≤ 2 TP 10 ± 1.4 1,57 (average) - Turbidity - 2 (median) ≤ 2 (median) Conductivity 1,109 ± 75 1,067 ± 0 - pH 7.1 ± 0,2 7.5 ± 0,3 - TC >10 2 for 80% of samples 9 for 95% of samples ≤2 for 80% of samples ≤20 for 95% of samples FC >10 ≤3 - EC >10 ≤ 3 for 95% of samples ≤5 for 80% of samples ≤50 for 95% of samples Sewer Mining (SM) technology as a Distributed Intervention for Water-Energy-Materials in the Circular Economy: A Real World Demonstration in the Athens Plant Nursery Klio Monokrousou1, Christos Makropoulos1, Konstantinos Tsimnadis2, Georgios Katsouras3, Nikolaos Tsalas3 1. Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, Heroon Polytechneiou 5, Zografou, 15780, Greece, kmonokrousou@gmail.com; cmakro@mail.ntua.gr 2. City of Athens, Department of Greenery and Urban Fauna, 5 Panag. Kanellopoulou, 11525 Athens, Greece, tsimnad@yahoo.gr 3. Athens Water Supply and Sewerage Company S. A (E.YD.A.P.) – Research and Development – 156 Oropou 11 str., 11146, Galatsi, Athens, Greece, gekats@eydap.gr; ntsal@eydap.gr Methodology Results The sewerage is extracted through two pumps that work alternately, from about four meters below the surface to fill in a buffer tank. The process starts when filtered wastewater enters a denitrification tank, where anaerobic microorganisms turn nitrates to nitrogen gas which naturally leaves the system. The denitrification tank communicates with a nitrification or aeration tank, where aerobic microorganisms turn reduced nitrogen compounds to nitrates. Subsequently, the biologically treated wastewater is transferred to the membrane tank and then the permeate passes through the UV disinfection unit and the final disinfected product flows naturally toward a storage tank to be reused mainly for irrigation purposes. The whole process is fully monitored through sensors and is automated using pneumatic actuated valves controlled by a PLC unit. The excess sludge produced from the SM unit along with the green and wood waste of the urban green spaces that end up in the Nursery, goes through a rapid composting process to produce on-site fertiliser. A heat exchanger and heat pump system recovers thermal energy from the wastewater to be reused for the technological processes of the c