Large-scale water reuse for agricultural irrigation in Milan from the Nosedo Waste Water Treatment Plant
4 June, 2050
Waste water source
The urban wastewater comes from the central eastern area of the City of Milan, coming under the discharger emissary of Nosedo and the collector Ampliamento EST.
The water quality parameters for the influent and effluent are visualized in the following table:
| Parameter | IN (mg/l) | OUT (mg/l) | % removal |
| BOD5 | 170 | <5 | 99 |
| COD | 300 | <15 | 97 |
| Total N | 27 | 6,5 | 76 |
| Total P | 3,5 | 0,9 | 74 |
| TSS | 190 | <5 | 99 |
Total coliforms in the reclaimed water average 40 – 200 CFU/100 ml, E. Coli do not exceed 10 CFU/100 ml.
Distribution System
During the irrigation period (April – September) the reclaimed water from the reclamation facility is discharged into a ditch called Roggia Verrabbia Bassa. This water is further derived to the fields by channels and ppen canals.
Farming system
In the area served by the agricultural water networks Emissario Nosedo, Roggia Vettabbia e Redefossi, the farming system is mainly extensive and traditional with fodder crops (grass, corn), rice and cereals.
Waste water treatment description
Nutrient removal : Tertiary treatment technologies remove Nitrogen and Phosphorus to avoid eutrophication in the Po valley, although relevant fertilizers for crops. N removal is performed by activated sludge recirculation with nitrification-oxidation followed by denitrification followed by the final decantation. To increase the N removal, also Mobile Bed Biological Reactor (MBBR) and Integrated Fixed Film Activated sludge are used. P removal is carried out by chemical precipitation and gravity sand filtering.
Pesticide removal : none
Disinfection : Disinfection takes place using UV radiation and paracetic acid.
Suspended solids removal : Coarse screening and fine grilling remove solid matter. Activated sludge bioreactors remove organic compounds.
Other : Odour removal
Capacity
The total capacity of the wastewater treatment plant is 1,250,000 population equivalents, a total annual volume between 135 and 150 hm³ is treated by the reclamation facility. From this volume, 80 hm³ is used every year for irrigation purposes.
Extent of the agricultural beneficiaries
3,700 hectares of land is irrigated with the reclaimed water.
Costs
The operational costs of the Nosedo wastewater treatment plant amount 0.139€/m3. The main operational cost component is the chemicals’ cost (30%), among other peracetic acid used for the disinfection. Other important operation costs are labour (21%), energy (20%), sludge disposal (15%) and maintenance (15%).
Type of agreement
The farmers associations called Vettabia Consortium groups 84 member farmes. The Lombardy region only charges an annual symbolic payment of 1,827 euros to the farmer association for the use of the reclaimed water.
Scientific results
Mazzini, R., Pedrazzi, L. and Lazarova, V. 2013. Production of high quality recycled water for agricultural irrigation in Milan. In: Lazarova, V., Asano, T., Bahri, A. and Anderson, J. (Eds) Milestones in water reuse: the best success stories. London: IWA publishing, p. 179- 190.
Zuccato E., Castiglioni S., and Mazzini R. (2009) Environmental pollution by drug residues. Ingengneria ambientale, 7/8, 353-357
http://www.depuratorenosedo.eu/en/images/stories/in%20cop%20ia%207-8%20-%20art.zuccato.pdf
