Sewage Treatment

WEC Projects has designed, installed and commissioned hundreds of packaged sewage treatment plants in Africa over the last decade.

Providing Quality Sewage Treatment Plants

WEC Projects is experienced in contracting on large bulk municipal sewage treatment facilities. With our focus firmly on the needs of our customers, our robust and high-quality packaged sewage treatment plants can be customised for specific applications. They have also been designed for easy transportation to any destination in Africa.

Our capabilities as an EPC contractor allow us to add value to bulk sewage treatment projects in South Africa and anywhere else on the continent.

Our various models of packaged sewage treatment plants

Key features include

  • Easy to transport
  • Heavy duty
  • Modular
  • Suitable for remote locations
  • Easy to instal
  • Complete and ready for site assembly
  • Easy to operate

Model A, B, C & D Packaged Sewage Treatment Plants​

The Model A-D ranges are completely factory-built, modular units. These plants are combined activated sludge and clarification treatment plants ready for site assembly. They are rectangular in shape and modules can be bolted together depending on the flow requirements and are designed for smaller flows up to 300 m3/day.

Our capabilities as an EPC contractor allow us to add value to bulk sewage treatment projects in South Africa and anywhere else on the continent.

Model R Packaged Sewage Treatment Plants​

The Model R ranges are partially factory built and site erected plants. These units are self-contained treatment plants that will treat most domestic wastewater and organic effluent. The capital cost, land usage requirements and erection time of the Model R systems are greatly reduced compared to a conventional treatment plant. The Model R plant is designed to run as an extended aeration activated sludge system and consist of two concentric circular walls. It can be located above or below ground to suit gravity flow or other site conditions. 

The plant retaining structures can be constructed from mild steel, concrete, or glass to steel fused tanks. The designed flow range is 150 m³/day to 3000 m³/day.

Key features include

  • Partially factory built and site erected
  • Reduced lead times
  • High quality effluent
  • Modular

Alternative sewage treatment solutions

These include Trickle filters, Sequential Batch Reactors (SBR) as well as our Model M, which houses Moving Bed Biofilm Reactors (MBBR).

Advantages

  • Inexpensive capital costs
  • Low energy requirements
  • Simple operation
  • Low sludge production
  • Better shock load recovery
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Trickle Filters

Trickle Filters are non-submerged media with attached growth-activated sludge and have been utilised in wastewater treatment for many years. They can be constructed in any geometry – round or rectangular-  to accommodate site conditions. Higher flows can be facilitated by building tower structures to reduce the plant’s footprint.  Primary sedimentation or septic tanks are installed ahead of the plant to reduce solids and COD loading.  A secondary semination tank after the reactor removes the biomass from the treated water, before being discharged at the applicable limit.

The plant retaining structures can be constructed from mild steel, concrete, or glass to steel fused tanks. The designed flow range is 150 m3/day to 3000 m3/day.

Sequential Batch Reactors (SBR)

Sequential Batch Reactors (SBR) plants utilise suspended growth-activated sludge technology in a batch process. Initially, the reactor is filled with screened wastewater.  Aeration and mixing then takes place, followed by clarification and finally decanting. All these unit processes occur in the same tank and there is therefore no need for recycle streams, etc. The phases are controlled to optimise each cycle of the process by means of a PLC.  In most cases, wastewater is continuously fed to a treatment plant.  The plant will need to be configured accordingly, as the SBR is batch treatment system.  This typically involves the addition of a second treatment tank and/or buffer tank.

Model M – Moving Bed Biofilm Reactor (MBBR)

Model M – Moving Bed Biofilm Reactor (MBBR) plant is an attached growth-activated sludge plant.  This means there is plastic packing media in the aeration tank to enable biofilm growth.  The aerobic zone is thoroughly mixed with the introduction of air, ensuring the packing media is kept in suspension. The benefit of the Model M plant is a reduction in aeration tank sizing due to the higher biomass concentrations.  Additionally, there is an improved nitrification rate to achieve denitrification due to the additional anoxic zone in the biofilm.  The Model M plant would require an upfront screen or sedimentation/septic tank for the removal of solids.  A secondary sedimentation tank after the reactor will clarify the effluent before being discharged.

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