_TETRA^® _ColOX^TM _{Bioreactor System}

Severn Trent Services offers the TETRA ColOX aerobic bioreactor system that uses a fixed-film biological process to provide superior nitrification, BOD reduction and filtration of suspended solids for water and wastewater applications where aerobic biological treatment is used. Configured as a submerged packed bed

reactor,  this  compact  space-saving  unit  offers  greater  efficiency,

operational  reliability  and  versatility  than  other  aerobic  biological

treatment processes. When combined with the TETRA Denite system

for biological  denitrification,  ColOX  provides  superior  biological

nutrient removal to meet strict discharge standards in a fraction of the

space required for other systems.

The ColOX system functions predominantly as a fixed-film system with

microorganisms attaching themselves to the surface of the media. The

voids between the media granules also serve as areas for suspended biomass growth, resulting in a significant increase in total microorganism  concentration.  Therefore,  the  detention  time  required  for  effective  wastewater  treatment  is  significantly decreased while the solids retention time is increased.

ColOX media is submerged, maximizing treatment efficiency and enabling greater process control. Media selection is essential and provides the maximum surface area and void volume for biomass growth and the filtration capability to assure superior solids removal. Media is selected on the basis of effective size (high specific surface area), uniformity coefficient, shape, hardness, and specific gravity. Air supplied from the bottom of the unit has a slow movement upward through the media which provides for very high oxygen transfer efficiencies.

Influent suspended solids and excess biomass are removed by  the TETRA Power Backwash^TM,  a procedure where backwash air and water are supplied to the bottom of the reactor as required to control solid loading within the reactor.

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Nitrification: applied loadings of ammonia-nitrogen of
30-50 lb/day per 1,000 ft³ of media can be handled at wastewater temperatures as low as 10^oC (50^oF) with
an oxygen transfer efficiency of at least 15%.

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BOD Reduction: high loadings of soluble organics (up to
250 lb of BOD/day per 1,000 ft³ of media) can be treated due to the unique media characteristics and the heavy-duty reactor construction. Intimate contact of the water with the concentrated biomass assures treatment efficiency.

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Suspended Solids Removal: the reactor media can accommodate high solids loadings and the effluent meets most secondary  treatment  standards.  Excess  solids  are  wasted  from  the  reactor  by  applying  backwash  air  and  water, simultaneously, to the bottom of the reactor at rates of 6 icfm/ft² air and 6 gpm/ft² water.

Any cooperation about web site, domain, please contact at mail m.colox@gmail.com

_TETRA^® _ColOX^TM _{System Components and Specifications}

Depending on the application, the TETRA ColOX system will consist of one or more packed bed bioreactors with all necessary auxiliary equipment. All units are custom designed to meet treatment and site requirements.

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Reactor Vessel: concrete or steel, round or rectangular - usually 18-20 feet deep.

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Reactor Bottom: nozzleless design; stainless steel air headers and pipe laterals; plastic jacketed 5000 psi concrete T Block underdrains.

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Reactor Media: monomedia granular sand with 2-3 mm effective size at depths of up to 10 feet.

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Support Layers: gravel in five layers totaling 36 inches deep in a reverse graded fashion.

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Backwash Air: distributed across the entrie area of the reactor bottom, supplied by a positive displacement blower at a rate of 6 icfm/ft².

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Backwash Water: supplied at a rate of 6 gpm/ft² with a low head centrifugal pump. The head loss across the reactor bottom is 4.0 inches water column.

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Process Air: utilizes the same distribution system as backwash air, each reactor is supplied by a dedicated blower.

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Reactor Valves: pneumatic or electric control valves with double acting cylinders. Isolation valves can be included.

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Instrumentation:  PLC  with  human  machines  interface  and  multiple  screens  included.  Also  includes  output  for  a centralized computer control and/or SCADA system. It also includes flow meters, analyzers, level switches, local panels and system alarms.

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Reactor Operation: Automatic with manual overrides. Backwashing and air bumping are time based.

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System Integration: Works well with other treatment plant processes such as overall nitrogen removal.

Any cooperation about web site, domain, please contact at mail m.colox@gmail.com