Wastewater Treatment in Castrocontrigo (León)

Analysis of the problematic of wastewater discharges in the municipality of Castrocontrigo, and technical proposal of the most appropiate solution for the treatment of wastewater generated in Morla de la Valdería, Torneros de la Valdería, Castrocontrigo, Nogarejas, Pinilla de la Valdería and Pobladura de Yuso.

In the towns of Morla de la Valdería, Pinilla de la Valdería and Pobladura de Yuso, the installation of a pre-treatment stage in the existing septic tank is planned, which will begin with a sand trap that will be periodically manually removed. Attached to the sand trap is a spillway that will allow the excess flows to be released. After the sand trap, a roughing system will be installed by means of a coarse grid.

In the case of Torneros de la Valdería, the construction of a waterwaste treatment plant with a purification system consisting of the following elements:

• Pre-treatment by desander and coarse grid roughing.
• Imhoff type decanter-digester of 2.5 m of Ø and 4.40 m of height.
• Two biological filters with 2m in diameter and 1.70m in height.

Finally, in the towns of Castrocontrigo and Nogarejas, the same treatment system is planned, consisting of the following elements:

• Roughing implanted in double channel. A screw screen will be installed in one of the channels and a coarse grid in the other channel.
• Pumping well in which 3 pumps (2+1) will be installed.
• Imhoff type decanter-digester of 5 m diameter and 4.98 m height.
• Bacterial bed of 5 m in diameter and 3 m in height.
• Buried secondary decanter of 5 m in diameter and 3.93 m high. The sludge will be purged in the central area of the decanter by means of a conduit that will connect it with the sludge purge chamber built next to the pumping well. A pump will be installed in this chamber to convey the sludge to the decanter-digester.
• Sampling pit, where a system for flow measurement is placed by means of a truncated cone weir with a strip.

In addition to the plants, the outfalls, spillways and actions necessary to reduce water infiltration into the sewage network are planned.