The Case of Milano-Nosedo Municipal Wastewater Treatment Plant Francesca Pizza Milano Depur
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Engineering Conferences International ECI Digital Archives Wastewater and Biosolids Treatment and Reuse: Proceedings Bridging Modeling and Experimental Studies Spring 6-11-2014 Agricultural reuse of treated wastewater: the case of Milano-Nosedo municipal wastewater treatment plant Francesca Pizza Milano Depur Follow this and additional works at: http://dc.engconfintl.org/wbtr_i Part of the Environmental Engineering Commons Recommended Citation Francesca Pizza, "Agricultural reuse of treated wastewater: the case of Milano-Nosedo municipal wastewater treatment plant" in "Wastewater and Biosolids Treatment and Reuse: Bridging Modeling and Experimental Studies", Dr. Domenico Santoro, Trojan Technologies and Western University Eds, ECI Symposium Series, (2014). http://dc.engconfintl.org/wbtr_i/24 This Conference Proceeding is brought to you for free and open access by the Proceedings at ECI Digital Archives. It has been accepted for inclusion in Wastewater and Biosolids Treatment and Reuse: Bridging Modeling and Experimental Studies by an authorized administrator of ECI Digital Archives. For more information, please contact [email protected]. Agricultural reuse of treated wastewater: the case of Milano-Nosedo municipal WWTP Francesca Pizza Process and Analytical controls - Milano Nosedo WWTP [email protected] WBTR Conference: Bridging Modeling and Experimental Studies Otranto, June 8-14 2014 EUROPE-ITALY-MILAN MILAN 2 MILAN Milan and the main Italian rivers BUSAN KOREA World water congress 16-21 3 September 2012 MILAN COMO MAGGIORE lake lake TICINO river Naviglio Martesana Canale Villoresi MILAN S.Angelo Lodigiano Confluence of the northern and Naviglio Grande southern Lambro River Naviglio Pavese Canale Muzza ADDA Chignolo Po river Confluence of Lambro and Po PO river A large agricultural district, just on the outskirts of the city… The WWTP of Milano Nosedo It’s the largest WWTP serving the city of Milano It treats sewage coming from the central and eastern area of the city, that means about 150,000,000 m3/year of wastewater The final water quality is suitable for agricultural reuse Total surface area involved: 40 ha Area occupied by the plant: 16 ha Population served: 1250000 p.e. * * Population equivalent = the average organic biodegradable load per person per day: it is defined in Directive 91/271/EEC as the organic biodegradable load having a five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day. The WWTP of Milano Nosedo Flow sheet Nosedo WWTP 3 Inlet flow = 5 to 15 m /sec Pretreatment Activated sludge Screening (coarse and Nitrification-oxidation Sand filtration Disinfection fine); grit and grease and denitrification; with P removal Peracetic acid removal phase final settling Reuse Sludge treatment Thickening Sludge Aerobic stabilisation valorisation Dewatering Thermal drying Odour treatment The WWTP of Milano Nosedo Main features Dry weather average inlet flow: 5 m3/s – 430.000 m3/d Max. inlet flow (wet weather): 15 m3/s of which 11 m3/s to complete treatment (4 m3/s subjected only to pretreatment) Average values of incoming and treated wastewater IN OUT % Parameter mg/L mg/L Removal BOD5 170 < 5 99 COD 300 < 15 97 Nitrogen tot. 27 6,5 76 P tot. 3,5 0,9 74 TSS 190 < 5 99 Milano-Nosedo WWTP Treated water quality: contractual, legal and actual values Legal limits for Legal limits Average Contractual agricultural values of Parameter U.M. values Leg. Dec. reuse treated water 152/2006 Min. Dec. since 2004 185/2003 Average bacterial charge in the final effluent pH 5.5 – 9.5 5.5 – 9.5 6 – 9.5 7.5 Suspended Solids mg/LParameter 10 35 CFU/100 mL 10 3 COD mg/L 100 125 100 < 15 Tot. Coliforms 40 – 200 BOD mg/L 10 25 20 < 5 Escherichia coli < 10 Nitrogen Total mg/L 10 10 15 7 Salmonella 0 P Total mg/L 1 1 2 0,9 Escherichia Coli CFU/100 mL 10 5000 10 < 10 Milano-Nosedo WWTP Treated water quality: ecotoxicological controls FROM DISINFECTION TO IRRIGATION 11 Milano-Nosedo WWTP: agricultural reuse of treated wastewater Annual volumes of treated water suitable for irrigation reuse Year 2005 2006 2007 2008 2009 2010 2011 2012 2013 Treated water 143.8 143.4 137.9 136.3 148.6 157.4 149.0 148.7 152.3 ( Mm3 ) Crops cultivated in the Vettabbia area: - 45% Corn - 15% Rice - 40% Grass and grain VETTABBIA Farmers Consortium • 84 farmers member ; 90 farms • Irrigated Area: 3700 ha (now), 4400 ha (in the past) • WATER USED – average values: - 700 L/s max for the irrigation of 1700 ha - 3000 L/s for the remaining 2000 ha • Farmers pay 1827,42 euros/year to Regione Lombardia, to have the concession rights to take water from the Vettabbia stream Milan water reuse scheme: following in footsteps of Cistercian Monks… One of the most important «key to success» of the water reuse scheme in Milan is the existence of a very old complex network of irrigation canals and an ancient agricultural activity that dates back to the Middle Ages, when the Cistercian monks realized the first land reclamation… The Vettabbia stream flows through the “monks valley” from Nosedo wwtp to Chiaravalle and Viboldone Abbeys North Nosedo wwtp Chiaravalle abbey Viboldone abbey And, last but not least, what about sludge? Sludge disposal 2011 (% of total dm) Sludge produced at Nosedo WWTP Year Tons of d.s. grds / p.e. x d Agricultural purposes 32% 32% 2011 12600 31 Incineration 2012 11840 30 Cement production sites 2013 11760 30 36% Sludge disposal 2012 Sludge disposal 2013 (% of total dm) (% of total dm) 11% 21% Agricultural purposes Agricultural purposes Incineration 48% Incineration 33% Cement production sites Cement production sites 56% 31% Nosedo sludge characteristics compared with European and National limits Nosedo sludge European Community Italy Parameter (2011-2012-2013) Working Document Directive (mg/kg dm) on Sludge 3rd draft D. Lgs. 99/92 Min Max 86/278/EEC (by 2015) Cd 20 - 40 5 20 < 0.5 2 Cr (tot.) - 800 - 56 128 Hg 16 - 25 5 10 < 0.2 2 Ni 300 - 400 200 300 21 63 Pb 750 - 1200 500 750 41 122 Cu 1000 - 1750 800 1000 247 487 Zn 2500 - 4000 2000 2500 268 795 AOX - 500 - - LAS - 2600 - - DEHP - 100 - - NPE - 50 - - PAH - 6 - < 5 * PCB 0.8 < 0.1 * PCDD/F - 100 (ng I-TE/kg dm) - < 1 * 46.3 * * Data referred to 2013-2014 Concluding remarks: the successful reuse of urban treated wastewater Delivery of high quality recycled water, ensured by an optimal treatment efficiency and by daily controls operated by qualified staff Cheap water resource, available all year The nourishing value of the nutrient enriched effluent improves the crop yields, and so the farmers’ revenues (is difficult to have a figures per hectar) Reduced need of artificial fertilizers Valorisation of historical heritage and peri-urban agriculture (“zero-kilometer products”) Public education programs and collaborations with non-profit organisations, research centers and Universities Thank you! http://www.depuratorenosedo.eu .