SECTIONAL VIEW OF A TYPICAL HYDRO BIOX SYSTEM

Process

• In the Hydro Biox system the wastewater is distributed through the special distribution system in the reactor.
• The organics contained in the wastewater when flows down the reactor through the specially developed silica based media, the immobilized microorganisms perform biological degradation of the organics & the media performs catalytic oxidation at the same time.
• An interesting feature of the system is that even after continuous operation for 6 months no clogging of the reactor has been recorded. The media matrix has demonstrated a marked increase in its performance of oxidation of organics expressed as COD, BOD in wastewater discharge from industries.
• The media is held between the strainer plates. A blower is provided in the space between the Hydro Biox media & the sand gravel media to provide air the microorganisms.

Hydroair in conjunction with CSIR has launched a system known as Hydro Biox System with Catalyst media for treatment of wastewater. The system has the basic feature such that bacteria are immobilized in the pores of the carbon matrix. The immobilized organisms are prevented from shock load application as the diffusion of the pollutants from the bulk fluid phase to the organism follows the principles of Fick’s law. In addition to the pores for immobilization of organics, the outer pore surface area is imparted with active sites of varying degrees of potential energy. The energetic active sites are abundantly available for solute molecules which leads to the condition that the solute molecules wander throughout the outer pore surface area, so that entropy of the solute molecules tend to increase.

The enhanced entropy of the system will tend to lower the enthalpy of absorption of solute molecules for the fixed quantity of free energy of the system. The decrease in enthalpy of absorption also favors desorption of the products formed. The oxygen molecules supplied for oxidation purpose also absorb at the activated sites. Oxidation of organic molecules will be accompanied with the quenching of electrons released from them. The electrons released from the oxidisable organic occupies the electron hole created during the excitation of electron from the valence band to conduction band as the fermi level is very closer to conduction band. Thus electrical balance is maintained. The hydroxyl ions formed from the electron and molecular oxygen combination helps in opening of complicated molecules such as phenol and naphthalene compounds. The transfer of electrons from oxidisable organics and other inorganic sulphur compounds has been confirmed through several experiments.

The electron conducting carbon matrix has demonstrated a marked increase in its performance for oxidation of organics expressed by COD, BOD in wastewater discharged for industries. The dissolved organics estimated as COD and BOD have been proved to be decreased to a credible level such that the treated wastewater deserves to be discharges onto open land. The treated wastewater has been used for irrigation and it has recorded the growth of vegetative plants, commercial crops and ornamental plants. The treated wastewater has been tested for carcinogenity and test results suggest that human population can safely handle the treated wastewater.

An interesting feature of the system is that the biomass production was recorded to be negligible so that clogging of the reactor was not recorded even after continuous operation for four years. The maintenance cost on treatment of wastewater through the system is estimated to be 30% of the existing treatment system. This technology has been extended to leather, textile, resin sago and starch processing, chemical and pharmaceuticals etc. and recently to domestic effluent also.

The wastewater is aerated and mixed by an airlift system in a reactor vessel packed with special matrix amorphous carbon. Air or Oxygen is introduced from the bottom of the reactor through venturi or diffusers providing fine bubbles for efficient oxygen transfer. The media has a low surface area. Unlike biological systems – there is no sludge formation. The microbes remain in a high growth phase – forming a fully developed food chain. The acclimated microbe population is resistant to shock loads.

Depending on the application, HYDROBIOX may be used alone or as a cost-effective pretreatment stage to upgrade existing treatment systems. Biochemical oxidation is an effective means of removing many organic contaminants from wastewater, but conventional aerobic systems have a number of drawbacks.