Serzedelo Sewage Treatment Works


The municipal sewage treatment plant at Serzedelo in Portugal serves a population of 270,000 with a design flow of 40.7Ml/d. The process consists of four plug flow aeration lanes and two carrousel reactors with aeration provided by thirty-six 25kW blowers dedicated as six per plug flow lane and two 400kW blowers for the two carrousel reactors. Instrumentation consists of dissolved oxygen and ammonia analysers in each reactor and final effluent nitrate and turbidity. The discharge consent for total nitrogen is 15mg/l.

Energy Reduction Goal
The plant operator, Tratamento De Águas Residuais Do Ave, wanted to reduce energy consumption whilst ensuring compliance with the discharge consent.

Meeting the Nitrogen Consent
Tratamento De Águas Residuais Do Ave decided to install a new control system using the CREA® intelligent platform, with the N-Control AI module. The inputs to the module are ammonia, nitrate, dissolved oxygen, final effluent turbidity and energy price. The module calculates a dynamic set point for dissolved oxygen to achieve the effluent quality requirements and sets a working frequency and performance for the aeration blowers. It sets anoxic cycle durations to achieve nitrification based on the nitrogen removal rate. Further, it takes into account variation in the electricity price tariff to reduce energy consumption peaks based on a 24-hour average final effluent nitrogen concentration.

Since the implementation of the CREA® intelligent control system, overall plant energy consumption has been reduced by 13% and aeration energy by 26% with final effluent in full compliance with the discharge consent.

Claudio Costa, General Manager of Tratamento De Águas Residuais Do Ave is very pleased. “The platform has produced savings from day one”, he says.

Intelligent control solutions in the UK
Te-Tech’s extensive capabilities in MCC, control panels, system integration is strengthen by our relationship with CREA@ for the design and implementation of artificial intelligence solutions

Te-Tech’s experienced team of electrical, control, software and process engineers specialise in integrating designs with the full capability to deliver complete process solutions, from panel design & manufacture, Systems Integration software and CREA® intelligent software into both new and legacy systems.

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Key Benefits


CREA® generates cost saving

N-Control module

13% reduction in energy consumption

Optimisation of electricity tariff

Full compliance with discharge consent

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