Water Supply and Drainage Master Plan

Contracting Entity:
Alcanena Municipality

Project Description

The settlements of Covão do Coelho, Vale Alto, Carvalheiro, Casal Saramago and Moita, do not have drainage and wastewater treatment infrastructures, and the current individual septic tank system does not guarantee adequate discharge conditions in the receiving environment. Therefore, technical solutions for wastewater drainage and treatment have been developed in line with the specific requirements of each site, imposed at a geographical, environmental and/or land-use planning, economic and technical level. Given the characteristics of the populations under study, four individual solutions were designed for each location (subsystems 1 to 4).

According to the constraints, the solutions considered viable were those that would allow the connection to already existing systems, or that would carry out the drainage and local treatment of the collected wastewater. Thus, it was proposed that the villages of Carvalheiro and Casal Saramago were endowed with autonomous drainage and wastewater treatment systems, and the subsystems of Vale Alto and Covão do Coelho (subsystem 1) and Moita (subsystem 4) were connected to the existing systems, namely the Minde system and the Malhou system, respectively, which have the capacity to drain and treat the additional flows of the mentioned villages.

The solutions developed also took into consideration the need to eliminate, in dry weather, the risk of effluent discharge, even if treated, in the receiving/soil environment. This condition was particularly relevant in the villages of Vale Alto, Covão do Coelho and Carvalheiro, as they are located in the Serra d’Aire and Candeeiros Natural Park, a protected area integrated in the Maciço Calcário Estremenho, created by the Decree-Law nº 118/79, of May 4th.

The project included the dimensioning of the infrastructure described below, by village.

Vale Alto (252 inhabitants):

• 5.8 km of sewers in corrugated polypropylene (PP), with a diameter of 200 mm (including the final segment);
• wastewater pumping station equipped with two electric pump groups (1 + 1), basket screen and operation building, equipped with a power generator;
• 0.2 km of HDPE rising main, with 110 mm diameter.

Covão do Coelho (587 inhabitants):

• 7.7 km of PP corrugated sewers, with 200 mm diameter (including connection to the Minde system);
• wastewater pumping station equipped with two electric pump groups (1 + 1), basket screen and operation building, equipped with a power generator;
• 0.3 km of HDPE rising main, with 110 mm diameter.

Carvalheiro (89 inhabitants):

• 3.8 km of sewers in corrugated PP and 200 mm diameter;
• wastewater pumping station, equipped with two electric pump groups (1 + 1), basket screen and a power generator;
• 0.1 km of rising main in HDPE and 110 mm in diameter;
• Wastewater treatment plant equipped with a pumping station (with two electric pump units (1 + 1) and a basket screen), a flow measurement chamber, a septic tank; two macrophyte beds, an evaporation pond and an operation building, equipped with a power group.

Casal Saramago (57 inhabitants):

• 0.95 km of sewers in corrugated PP, with 200 mm diameter;
• WWTP equipped with headworks (with screen system), a septic tank, a bed of macrophytes and an operation building.

Moita (42 inhabitants):

• 1.8 km of sewers in corrugated PP, with 200 mm diameter (including connection to the Malhou system);
• a wastewater pumping station equipped with two electric pump groups (1 + 1), basket screen and operation building, equipped with a power generator;
• 0.5 km of HDPE rising main, with 110 mm diameter.