The construction of the new Ortiga WWTP has already entered the pre-start phase

Project Description

The current Waste Water Treatment Plants (WWTP) of Ortiga I and II are constituted by buried compact units, in poor state of conservation, thus not having capacity of treatment for the population agglomerates they have to serve. Taking into account the quality demands currently required for the effluent discharged, the space available for implementation, the type of treatment currently in the WWTP and the installations conservation state, it is technically and economically more advantageous to replace the existing WWTP, as well as the adoption of a new configuration of the sanitation subsystem, and the new WWTP should be based on an activated sludge system.

At the sites of the current WWTP (Ortiga I and Ortiga II), a pumping system will be built, more precisely a pumping station in Ortiga I and another in Ortiga II.

The WWTP of Ortiga municipality of Mação will be executed from scratch in a place close to the village.

The recommended treatment solutions will take into account the quality objectives for the effluents to be discharged into the receiving environment, the amount of population and also the current and future affluent flows, the intended treatment line, the rules and criteria identified as binding in the Specifications Book and the space available for the implementation of the solutions.

In the design of the object solution of the present proposal, the selection of proposed electromechanical materials and equipment was taken into account, which are characterized by a high level of quality and in which they score high levels of robustness and mechanical and chemical resistance.

The Ortiga WWTP is dimensioned, both in hydraulic and procedural terms, to respond to a population equivalent to 630 inhabitants. In the planned WWTP, the adopted operating principle corresponds to the biological treatment by active sludge systems in a prolonged aeration regime. In this context, a line of treatment of the liquid phase with the use of a biological reactor with anoxic zone is individualized.

In regard to the liquid phase, the raw waste water will flow to the entry site which will have a pumping station to pump the effluent to a compact unit to carry out the sieving and de-sanding processes. Between the process of sieving and removal of sand and the previous pumping station, the flow of raw wastewater affluent to the installation will be quantified, using an electromagnetic flowmeter.

Afterwards, the residual water is sent to the biological treatment stage, which includes the following elements:

· Biological reactor with anoxic zone

· Secondary lamellar decanter.

The final effluent, clarified and treated, is discharged into the water as mentioned above. In regard to the solid phase, the treatment begins in the decantation stage in the secondary lamellar decanter, continuing with the gravitational thickening of the excess sludge in a frusto-conical thickener silo with a diameter of 2.5 m and a bottom inclination of 60°.

The sludge extraction will be done gravitationally from the apex of the cone. The thickener silo will have a connection for discharge in the thick sludge transportation vehicle to another larger EPAL WWTP, as well as 3 sockets with respective sludge sediment control valves. As far as the gas phase is concerned, only its application in the lifting stations was foreseen. The applied deodorization system corresponds to a deodorization system by activated carbon filter, having the H2S values at the outlet of the filter be less than 0.1 ppm and the duration of complete filling, 12 months. The WWTP also has an Exploration Technical Building that will have a shower room, electric room, laboratory and a room where the airing blowers to the diffusers will be installed.