Can Cabanyes project: reclamation of water and nature

Ajuntament de Granollers (2003-now)


Can Cabanyes (Catalonia – Spain)

X: 438917.67 Y:46022144.64


To create a tertiary wetland for supplying reuse water to the city

To create a tertiary wetland for supplying reuse water to the city

To use alternative water resources in the watering of public green areas

To enhance the biodiversity with the creation of wetlands in Can Cabanyes

To put into practise an environmental best practise that can serve as an example at the local level



The source of waste water is a mixture of industrial and domestic waters: Mixture The technical specifications according to the design data: WW flow/day: 30.000 m3/day BOD Biological oxygen demand: 250 mg O2/l

BOD Biological oxygen demand: 250 mg O2/l Suspended Solids: 200 mg O2/l Total N: 63 mg/l Total P: 10.7 mg/l


The Can Cabanyes system is an indirect reuse system where the reclaimed water is placed into a wetland (and later in tanks) before its distribution and use.


5a) Treatment:

Conventional treatment in WWTP plus tertiary treatment in a constructed wetland WWTP 112.154 equivalent inhabitants 1 ha constructed wetland

5b) Post treatement desinfection:

Disinfection and filtration
Disinfection: chlorination of water (two dosing pumps, automatic chroline analyzer, remote control)


Network of pipes, tanks and pumps to distribute the reclaimed water from Can Cabanyes to the city

Transport and storage indicators:


Green areas irrigation and maintenance of the ecological flow of river Congost

Uses indicators:

Total volume of reused water produced 120.000 m3/year

Agricultural uses:

Agricultural lands surface with reused water irrigation 0 Consumption of reused water in agriculture 0 Crops 0

Industrial uses:

Consumption of reused water in industry 00

Consumption of reused water in industry Sector (chemical, paper and pulp, beverage, textile…) 0

Urban uses:

Use (green areas, street cleaning, fire protection systems…) 5.000 m3/year

5.000 m3/year in watering green areas

(due to the rish of Legionella, the street cleaning has Consumption of reused water in each use (i.e. green areas) been temporaly discarded)



Explain which are the main costs specific to water reuse and how is their frequency (transport, additional treatment…)

Main Costs indicators:

a) Investments

Cost of the project (until putting into operation) 231758,67 €

b) charges

Maintenance expenses 1000 (€/year) Consumables expenses 400 (€/year) Energy expenses 1100 (€/year)


a) Environmental benefits

Efficient water management reduce water footprint use of alternative water resources Creation of a water body for the biodiversity Local production of water Excelent water resource in case of drought Reduction ot the consumption of underground water

Reduction ot the consumption of underground water Great contribution for the maintenance of water levels in the river Congost and wetlands in Can Cabanyes Better treatment of waste water before its urban use or its discharge in natural habitats Water reused is an excelent response to mitigate and adapt to the climate change

b) Economical benefits

Local management of the reused water network can optimize the supply costs Non-expensive maintenance of the system Save of fertilizers in gardening and agricultural uses Options to purchase the reused water to industrial users

Options to purchase the reused water to industrial users

c) Social benefits

Reuse water is a great strategy in areas with lack of water Great alternative resource in societies with water deficit due to the increasing demand of water The use of recycled water enables the reserve of the high quality water for the most demanding uses Reused water supply is reliable, because it isn’t dependent on weather variations or competes with drinking water supplies The production of reuse water with constructed wetlands contributes to the creation of new landscapes Quick response to the needs of local water demand on green areas

Quick response to the needs of local water demand on green areas


High initial investment Long-term profitability low social perception and lack of awareness of the benefits of water reuse Difficulties in the implementation in some industrial activities


Cada vegada més hi ha més empreses interessades en millorar el seu comportament ambiental mitjançant el consum d’aigua reutilitzada, una bona pràctica ambiental, ja que actualment la indústria consumeix el 11% de l’aigua potable consumida a Europa.

L’aigua reutilitzada industrial es consumeix en usos no potables, com ara la refrigeració, l’aigua per processos i les activitats de construcció. En sistemes ben optimitzats, aquest subministrament pot arribar a suposar fins i tot un estalvi econòmic, ja que l’aigua regenerada és un recurs local que esdevé una bona inversió econòmica vistos els escenaris futurs d’increment del preu de l’aigua..

Al projecte ALERA l’Ajuntament de Granollers i la Universitat Politècnica de Catalunya promouran aquest tipus de reutilització i estudiaran la seva viabilitat.