aWARE demonstration site
The demonstrative actions of the aWARE project, including the operation and optimization of the MBR-PAC-NF prototype will take place in the existing Wastewater Treatment and Water Reclamation Plant of Baix Llobregat. This will allow comparing the proposed innovative treatment scheme with the existing full scale plant in terms of water quality and treatment costs as well as environmental impacts and benefits.
Baix Llobregat WWTP, with a design capacity of 3.25 m³/s, consists of a conventional scheme comprising primary clarification and an activated sludge biological treatment for organic carbon and nutrient Removal (N & P) followed by secondary clarification.
The Water Reclamation Plant aims at producing reclaimed water for the different uses considered in Barcelona’s water reuse sheme. Baix Llobregat Water Reclamation Plan (WPR), which has a design flow rate of 12,600 m³ /h and a peak treatment flow rate of 14,400 m³/h, consists of the following processes (Figure 2):
- Two regulation basins and a total of 4+1 lift pumps with a unit flow of 3,150 m³/h.
- Three sedimentation units, each unit consisting of a 90 m³ coagulation tank with PAC injection, a 90 m³ sand and anionic polyelectrolyte injection tank, a 198 m³ maturation tank, and a clarification basin with a surface area of 42 m².
- Ten microfiltration rotary disc filters with 10 μm mesh.
- Four ultraviolet light (UV) disinfection channels with a total of 216 lamps per channel arranged in two banks per channel.
- A post-disinfection with sodium hypochlorite and oxygen saturator.
The water treated by this process has the “basic quality”, that allows reusing it for several applications including ecological flow and wetlands mantainance as well as for industrial and municipal water reuse. However, there are other applications which require further treatment and satellite treatments are implemented in order to archive the requested for irrigation and direct aquifer recharge for saline intrusion barrier.
The EDAR plant that was built in 2009 enables water from the basic reclamation process to be demineralised from 2000-3000 to 800 μS/cm. The demineralised water is then mixed with a suit able portion of water from the basic reclamation process, after passing through closed sand filters and 5 micron cartridge filters, as to obtain final reclaimed water suitable for agricultural irrigation with a similar conductivity to the Llobregat River, which is the conventional supply source of local farmers.
Saline intrusion barrier
The basic water reclamation plant also supplies water to the advanced water reclamation facility for the seawater intrusion barrier in the Llobregat Delta aquifer. This facility allows the injection of reclaimed water through 15 wells, forming a barrier between the Mediterranean and the aquifer. The reclaimed water injection capacity of the facility is 15,000 m³/d. supplied from the UF and RO stages after which water is disinfected with ultraviolet light. The water finally injected into the aquifer is a 50/50 mixture of water treated by reverse osmosis and water treated by the ultrafiltration stage.