Project:
Technical Assistance to the Works Management for the Mungia Stormwater Tank 

Promoter:
Water Authority for Bilbao Bizkaia

Synopsis:
The works on the new Munguía Stormwater Tank are focused on the storage and control of excess wastewater and rainwater flowing through the Interceptors of the Munguía system's sewage network, prior to pumping it to the Munguía WWTP, in such a way as to avoid discharges into the watercourse during the rainy season.

The works are located at the Munguía Pumping Station on the right bank of the Butrón river. This is intended to provide a solution for the continuity of the current tank associated with the pumping station, making it possible to increase its retention capacity.

The stormwater tank is a completely buried tank with a total retention volume of 10,475 m3 distributed in 3 chambers, so that each chamber can be filled and emptied sequentially, minimising maintenance. These three chambers are connected by perimeter walkways that allow access to them, as well as a dry gallery, through which the chamber emptying pipeline runs.

The tank has a natural outlet to the river and 2 Axial submersible relief pumps of 75 kW nominal power and 1.500 l/s of unitary flow in each one that allows a forced outlet to the river, despite the fact that the water level of the river is above 0. 
A powerful ventilation and deodorisation system has been installed in the tank, which allows internal access to both wet and dry areas without the need for Personal Protective Equipment.

Also installed are 2 motorised floodgates, 6 x 700 l/m tilting cleaners, numerous flaps, stairs leading down to the chambers, water supply to the tumblers and cleaners, lighting and electrical installation with flood prevention.