My project is wastewater treatment plant in Cadiz that uses wastewater in beneficial way to produce products and also turn it into an architectural didactic place to make people raise their concern about the water condition
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Cadiz is the city located by the coast in southwest of Spain which has a long history of polyculture as well as aquaculture. Since 1940, large piece of land along San Pedro River that was once used to be salt pan now has turned into fish farm. As the result of this, the level of ammonia in the water is high due to the high density of fish farm. As the number of fish farms grows, the wastewater discharged to the water is also increase
Ammonia, which is the product of the decay of these wastes, has been discharging into the channel down the stream which the natural park is located causing the interruption in the preserved land’s ecosystem. To protect the natural park, the level of ammonia must be lowered before it could enter the preserved zone.
To reduce the ammonia in the water, algae-based waste water treatment is introduced because the fact that for algae to grow, it needs carbon dioxide, sunlight, and most importantly, ammonia as its source of nutrient. Therefore, in the end of this water treatment process, algae are also the product of it which could be extracted and turned into biofuel. The water from the river is guided into the system through the grit bar to screen out the large objects, and then to the sedimentation ponds to remove sludge. After that, the water will be transferred into the algae cultivation process to remove the excess nutrients in the water. Algae will be harvested and to the algae extraction lab while the filtered water will be discharged into the river with lower level of ammonia. Also, the system will be used as the indication of water condition and I envision it as a research center of the water treatment and the public space for visitors to learn and appreciate the process of the system.
The site will be located where San Pedro River and Valdelagrana Road intersects which is where the end of fish farming and the start of the natural park meets to prevent the excess of ammonia in the water before it entering the natural park. The plant is placed by the left side of the river to connect with the two existing access path which are the road connected to the main street where the parking is available, and the dirt trail accessible through the natural park by either bicycle or walking.
The buildings are divided into mainly three levels, lower level, ground level, and roof area. Lower level is the area where wastewater treatment plants, the research lab and the office are placed. Ground level consists of the main reception which is connected to main accessible routes and the pedestrian path where visitors could experience and appreciate the space. The roof area is the green roof connected to the ground using slope to create the seamless transition between the roof and the wetland landscape.
There are two main circulation paths, one for visitor and other for workers. Visitors will enter through the reception hall, and then proceed to the main path which they will first encounter the grit bar filter and the sludge tank. And then, they will circulate around the sediment ponds where they could experience the 360° view of the site and landscape. The next facilities they will run into are the algae raceway ponds and algae extraction and research lab. They will then proceed to the outlet of treated water at the end of the plants. At the end of the path, visitors could choose to have some rest the restaurant or follow the path that makes a loop to the roof garden and back to the reception. Service path for workers in the other hand is the slope down to the lower level through the sides of the site. It leads to each treatment plants, the lab and the storage area where only workers are permitted.
The tide will slow the mass of moving water fed into the system so that the residence time will allow algae to be cultured. With the interval of the tide twice a day, residence time will last for 4 hours allowing the water to settle with the right condition to culture algae. The tide will also reveal part of the land in the site when it is low creating the extra public space and gathering point for people.
In the end, this wastewater treatment will lower the level of ammonia and the ammonia entering the natural park by using algae to consume nutrients and it will be a research and study ground that gives the information and raise the awareness of the water condition to the visitors.
