Sludge removal from four WWTP ponds in Baixo Alentejo

News date: 1 October 2021

The works referring to the tender launched by AgdA - Águas Públicas do Alentejo, S.A. for “Removal of Sludge from Ponds at the WWTP of Almograve, Campo Redondo, Mina de São Domingos and Rio de Moinhos” were awarded to BioSmart.

The works are carried out in phases over a period of 180 days, in four different installations of the system managed by AgdA within the scope of SPPIAAlentejo – Public Integrated Partnership System of Águas do Alentejo.

The public procedure, with a maximum value of 365 thousand euros, estimates 7,864 m3 of sludge to be removed after surface drainage, resulting in a final estimate of 2,768 tonnes of sludge.

The final amount to be borne by AgdA will essentially depend on the volume of sludge removed (m3) and the amount of sludge (tons) sent to its final destination (agricultural recovery or composting).

In the case of the Almograve and Campo Redondo WWTP, after surface drainage, the cleaning and removal of the accumulated sludge inside the aerated lagoon will be carried out using a raft with pumping to suction the sludge and send it to a mobile dewatering unit at install by BioSmart.

In the case of the WWTP at the São Domingos Mine and Rio de Moinhos Mine, after draining the surface layer, the removal of sludge will be carried out using mechanical means of the rotating type with a cleaning bucket without teeth and rubber caterpillars (or equivalent), so as not to damage the screens, after natural drying in the lagoon.

The Almograve WWTP serves the populations of Almograve, Cruzamento do Almograve and Longueira, having been dimensioned to treat, in the project's horizon year, the urban wastewater corresponding to around 1,247 inhabitants.

The treatment line consists of a preliminary treatment with a mechanical cleaning grid, an aerated lagoon (the target of the intervention), two decanters and a sludge stabilization lagoon.

The Campo Redondo WWTP serves the town that gives it its name and has around 113 inhabitants.

Its treatment line consists of preliminary treatment with a mechanical cleaning grid, septic tank and optional pond (target of the intervention).

The Mina de São Domingos WWTP serves the population of Mina de São Domingos and has been operating since 2004. Sized for a population of 3,500 equivalent inhabitants, the WWTP has a treatment capacity of 315 m3/day.

Its treatment line consists of preliminary treatment with a mechanical cleaning grid, 1st series aerated lagoon (target of the intervention), 2nd series aerated lagoon, maturation lagoon and drying beds.

The Rio de Moinhos WWTP serves the town of Rio de Moinhos and was dimensioned to treat, in the project's horizon year, the urban wastewater corresponding to about 2,000 inhabitants, having started operating in 1992.

The treatment line consists of Preliminary treatment with a mechanical cleaning grid, aerated Pond with 2 Tornado-type aerators (target of the intervention) and Facultative Pond.