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Hitachi Aqua-Tech Engineering Pte. Ltd.

Conventional Sewage Treatment Plant uses activated sludge process to biodegrade and remove pollutants from wastewater for discharge or reuse purposes.


Conventional sewage treatment systems are based on activated sludge process and its variations. These included

  • Activated Sludge System
  • Extended Aeration
  • Sequencing Batch Reactor (SBR)
  • Moving Bed Bioreactor (MBBR)

Prefabricated Extended Aeration System

Conventional sewage treatment system can be prefabricated with durable FRP tanks and minimum site installation works are involved.

Conventional sewage treatment plant occupies larger space than MBR plant as separate activated sludge reactor and secondary sedimentation tank are required. Site works and civil works are minimised as the plant is prefabricated in FRP Tanks. In order to meet more stringent reuse requirement, which is beyond what can be accomplished by conventional sewage treatment plant; a tertiary treatment (filtration) is incorporated when requested, to further polish the secondary treated water.

Process Diagrams

Standard Features

Treatment Chambers

  • Solid separation chamber for pollutants buffering
  • Attached-culture anaerobic biological treatment chamber for BOD and other pollutants removal
  • Attached-culture aerobic biological treatment chamber for BOD and other pollutants removal
  • Sedimentation chamber for treated water clarification and settled activated sludge returning
  • Chlorination chamber to disinfect and reduce the number of microorganisms in the treated water before discharge

Variation of Conventional Activated Sludge System

Hitachi Aqua-Tech also designs and installs Sequencing Batch Reactor (SBR) and Moving Bed Bioreactor (MBBR) sewage treatment plants (STP) for our clients.

Sequencing Batch Reactors

Sequencing Batch Reactor is a batch process reactor where different reaction phases takes places in sequence: fill, react, settling, idle; When one cycle of the treatment is completed, the next batch of the wastewater is filled into the tank again and the process continues.

SBR process is suitable for small to medium sized sewage treatment plant.
Some features of the SBR systems are:

  1. Space saving
  2. Low capital costs
  3. Low running costs
  4. Easy operation and maintenance management
  5. Good-quality treated water
  6. High nitrogen & phosphorus removal rate

Moving Bed Bioreactor

Moving Bed Reactor process utilises attached growth biological process for BOD removal. Due to the high density population of the different types of bacteria growing in the carriers, MBBR process improves reliability, simplify operation, and require less space than traditional wastewater treatment systems.