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Cyclic Biological Treatment (CBT)

State of the Art Technology – For the Future and Beyond!

As pressure on the world's natural resources continues to grow, wastewater treatment facilities are becoming ever more important to the protection and preservation of our environment. Urban and rural populations are continually expanding, causing many existing facilities to operate at or over design capacity while utilizing aging equipment and technology. Modern communities understand that inadequate wastewater treatment poses serious concerns for our precious environment and have enacted increasingly stringent governmental requirements.

The two most significant barriers confronting the wastewater treatment industry are simple aesthetics and, of course, cost. Treatment facilities are regarded by the public as odorous, unsightly, and unsanitary, leading communities to locate them as far away as possible. In addition, traditional treatment processes have generally utilized multiple basins and excessive mechanical equipment, further driving up land use and cost. 

Our goal at International Wastewater Technologies, Inc. (IWT) is to meet these challenges with the most efficient and cost effective technologies available. IWT has developed patented technologies that enable our CBT™ Process to produce tertiary quality effluent in a manner that is environmentally friendly, aesthetically pleasing, easily maintained, and energy efficient. The IWT development team will continuously strive to improve our methods of treating residential, commercial, and municipal wastewater.

International Wastewater Technologies is proud to present the CBT™ Process, rapidly becoming the wastewater choice of the future.


The Cyclic Biological Treatment (CBT™) Process was developed by International Wastewater Technologies (IWT) to process on-site wastewater. The high quality effluent produced by the CBT™ Process protects our precious ground water, watersheds, and quality of life.

Frequently, the design of treatment systems must cost effectively address a wide array of challenges over and above simply treating wastewater:

> Limited or Inadequate Infrastructure
> Land Use
> Odor Control
> High Water Tables
> Equipment Maintenance
> Energy Usage
> Aesthetics

IWT has developed the CBT™ Process, with patented influent velocity reduction devices, to address these issues while maintaining cost efficiency.



For quite a long time, the most widely used wastewater treatment method has been the activated sludge process. Traditionally, the activated sludge process uses separate basins to accomplish flow equalization, aeration, solids settling, effluent withdrawal, and filtration. This process is a very reliable and proven method of treatment, but unfortunately uses an excess amount of tankage, equipment, and energy. 

Land and energy costs have risen considerably, and will continue to do so in the future. In order to conserve land and energy, the wastewater treatment industry has focused on methods of performing multiple treatment steps of the activated sludge process in a single basin. The Sequencing Batch Reactor (SBR) was developed to aerate, settle, and withdrawal effluent from a single basin. The primary drawback of SBR's has been the need for a separate basin and mechanical equipment to divert and hold influent so as not to upset the settling and decant processes. Attempts have been made to accept influent on a continuous basis, but usually at the cost of increased mechanical equipment and maintenance. 

IWT has made great strides in the improvement of this area of wastewater technology. The patented and patent pending CBT™ Process successfully accommodates continuous inflow of wastewater while utilizing a single treatment basin. The CBT™ Process accomplishes this without the need for an influent control valve or separate basin to hold diverted flow. It does not utilize a baffle wall with underflow weirs which may create turbulence within the sludge blanket during the settle phase, creating potential for washout. The CBT™ Process uses influent velocity reduction devices with no moving parts that simply control influent hydraulics better than other designs of similar theory.

Cyclic Biological Treatment (CBT) Process
A single Basin Reactor Wastewater Treatment Plant

Developed by International Wastewater Technologies, CBT™ Process is a low cost highly efficient wastewater treatment plant – utilizing the patented Velocity Reduction and Distribution (VRD™) technology components.

Excellent for use in rapidly developing and over-populated third world countries or as conversion units in existing, out dated private treatment facilities – CBT™ is an economically viable solution.

International Wastewater Technologies (IWT) has made great strides in the improvement of current wastewater technology. The patented component of the Cyclic Biological Treatment (CBT™) system allows continuous inflow of wastewater while utilizing a single basin. Flow through the CBT™ basin is never interrupted. This proprietary design combines continuous inflow with intermittent decant, which minimizes basin size and the need for multiple basins.

Technology – The CBT™ is like a Single Basin Reactor (SBR), and an ICEAS system in that is process-controlled through time. They all carry out all the steps of flow equalization, biological oxidation, nitrification, denitrification and solids-liquids separation in the same basin. You may conclude that all the advantages of the SBR and ICEAS as compared with the Continuous Activated Sludge (CAS) system apply to the CBT™ as well.

The CBT™ Process, however, does not require an influent control valve or another basin to hold diverted flow such as is the case of other SBRs. It also does not have a baffle wall, which increase the width of the basins in other technologies. Systems that utilizes underwater weirs are known to create turbulence within the sludge blanket during the settling phase, with is a potential for washout and has a mechanical high maintenance draw-down decanter, which have been known to fail.

Operation – Automation makes the CBT™ Process very easy to maintain and operate. The entire operation is on a 24-hour cycle. The clock/microprocessor automatically coordinates all the equipment and phases of each cycle. The system will also automatically switch to a storm cycle when the infow reaches a certain level. The CBT™ Process can accommodate up to six times the average daily flow during a four hour period without effluent degradation. The operation can manually adjust any phase or cycle to respond to varying loading conditions.

Automation also reduces the demand on labor by at least 50%. Labor and maintenance costs are significantly lower than comparable systems using trickling filters; continuous activated sludge, rotating biological contractors or oxidation ditches. A Supervisory Control and Data Acquisition (SCADA) system can be provided to monitor plant operations, collect, store and analyze data for our customers.

Operational flexibility offered by the CBT™ Process large hydraulic capacity basins provides a large surface area for clarification of supernatant, the basin accommodates shock loads unlike any other system and the CBT™ Process can accommodate 20 to 30 hours of retention time.

Expansion – Flexibility in the design allows for easy expansion, as needs increase. To accommodate larger volumes of wastewater, several CBT™ Process basins can be constructed in parallel to handle the increased supply of influent. In other technologies, it is much more difficult and expensive, as they require multiple process units, plumbing, pumps, controls, etc.

Since all the CBT™ operations are in one basin, planning construction and subsequent expansion are simpler and more cost effective.

Why Utilize the CBT™ Process? Water is a precious commodity, when millions of gallons is wasted each day, why not take steps to extract the most water out of your waste for other usage and savings. Because today's waste infrastructure is overcapacity and current technology continues to damage our environment, the CBT™ Process produces the safest biologically treated effluent in the least amount of time.

Overview of Wastewater – Wastewater usually is composed of 1% percent solids versus 99% water. Extracting this 99% water is viable, both economically and environmentally. There are three methods in use for treating domestic wastewater; (1) Primary, (2) Secondary, and (3) Tertiary. CBT™ is Secondary Treatment producing Tertiary results due to the efficiency and nature of the system.

The CBT™ Process System – Cyclic Biological Treatment (CBT™) Process was designed and patented by International Wastewater Technologies, Inc. (IWT). The patented technology is cost efficient, energy efficient, easily installed (as well as adaptable to existing system), the most maintenance-friendly wastewater treatment technology on the market and it was designed to provide many years of trouble-free sewage treatment service.

The CBT™ Process systems can accommodate flows from 1,000 GPD to 25 MGD (with modular expansion allowing for endless possibilities).

Wastewater plants can be installed in less time than conventional systems. The reason, true single basin technology, less piping, less overall equipment requirements, less excavation, installation and coordination. Remember … time is money!

How Did IWT Accomplish This Task? IWT has developed a way to reduce the velocity of the wastewater flow entering the treatment basin. This is accomplished at the same time the settle and decant phases of the treatment process occurs. The wastewater is then distributed in a laminar fashion, into the biomass unlike any other system.

By controlling the influent hydraulic flow velocities, the CBT™ Process treats the sewage immediately without the requirement of separate primary clarifiers, separate secondary clarifiers and separate aeration basins (all sources of odors). This reduction in separate basins is a great cost reduction too!

The CBT™ Influent Gate Housing – This is where the Velocity Reduction and Distribution (VRD™) technology begins. The theory of turbulence, by-product aeration, and splash energy to reduce influent velocities is utilized here. Plus it is all non-mechanical.

The CBT™ Process Floating Decanter – The benefits of the CBT™ Process floating decanter is of a simple design, its non-mechanical, so it never breaks. There is little to no maintenance. The decanter is internally floated, and features maintenance – free ball check valve intake ports. The ball check valves are not exposed to the elements.

Biological Process – The CBT™ Process typically takes place over a four-hour cycle which is automated via an electronic timer throughout a 24-hour day. During the cycles, influent is received continuously while other biological reactions occur. They are Nitrification, BOD5 Oxidation, Hydrogen Sulfide Gas Intervention, Denitrification and Phosphorous Removal. This is known as Biological Nutrient Removal (BRN).

Importance of Denitrification – High levels of Nitrates are very polluting which has been linked to Algae Bloom and Blue Baby Syndrome (birth defects).

Importance of Phosphorous Removal – Phosphorous is a nutrient for algae growth that often must be removed. Under the ideal conditions created by the CBT™ Process, phosphorous removal is accomplished by biological means. The microorganisms in the mixed liquor are able to remove an amount of phosphorous from the wastewater over and above the amount that is required for growth termed “luxury uptake.” This can be more cost-effective than chemical treatment.

Importance of Hydrogen Sulfide Gas Intervention – Hydrogen sulfide gas intervention reduces the deadly gases created by the sewage treatment process, which is highly corrosive and has a rotten egg odor.

Safety Features – Some of the safety features included in the CBT™ Process System are: Float Tree Automation or transducers that automate the process through time even during storm flows, Emergency Gravity Overflow, Standby Generator, Emergency Telephone Dialer/Alarm, Supervisory Control and Data Acquisition (SCADA).

Disinfection – This can be accomplished with a disinfection system suitable for the appropriate application. IWT has found that because our effluent quality has been so superior, maintenance of such disinfection apparatuses have been decreased compared to other systems.

CBT™ Manufacturing – IWT uses the finest, quality parts utilizing local manufacturers, whenever possible, for better and more expeditious service to our customer. IWT specifies the quality of the parts installed which reduces the lead-time necessary for the manufacturing and installation of the wastewater treatment plant.

When Should CBT™ Process Be Used?

  • When your current facility/technology has failed.
  • When your current facility is at capacity.
  • When your current facility has offensive odors.
  • When your business requires an economic solutions to applying a wastewater treatment system.
  • When your current facility does not meet environmental standards or other requirements.
  • When your maintenance costs, energy costs and other costs are reducing your profits and the possible growth of your business.
  • When you are in need of a state-of-the-art wastewater treatment facility.
  • When your business property is limited in size and requires a solution to its wastewater needs.

Applications of the CBT™ System
Apartments, Condominiums & Townhouse Complexes • Schools • Campgrounds • Retreats & Parks
Golf & Country Clubs • Community Centers • Business & Industrial Parks • Airports • Shopping Centers • Office Buildings • Restaurants • Hospitals • Hotels & Resorts
Cities • Towns Large Subdivisions

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For more information please contact our sales department at
(808) 833-2298 or