Improved Apparatus for Carrying Out a Bioreaction

Introduction

Wastewater from various industrial and domestic sources contains many hazardous chemicals, which have to be treated prior to discharge into natural streams. Such treatment is done by employing an apparatus for carrying out bioreaction. The presently used apparatus, i.e. bioreactors have limitations such as low rates of bioconversion, non uniform mixing characteristics, adaptability for varying feed pattern or feed concentration, etc. In order to overcome these limitations a fluidized floc bioreactor has been developed. This improved reactor does not need any solid settling devices and no carrier material is required for biomass growth.

The bioreactor comprises of a cylindrical or tapered reactor disposed in a vertical position. Truncated cones are provided at the upper end and lower end to act as phase separator and liquid distributor respectively. An inlet port is provided at the lower end of the reactor for introduction of wastewater. Outlets for treated water and gas are provided at the top of the reactor. The height and the diameter are generally in the ratio of 5:1 to 30:1. The preferred ratio is however between 10:1 to 20:1. A number of outlets are provided at different heights along the vertical length of the reactor for removal of the flocs. Bio conversion is brought about by flocs of micro-organisms present in the reactor The fluid containing the reactants enters at the inlet preferably with such velocity so that the flocs are retained in the fluid state. As soon as the bioconversion progresses, the flocs grow in size and settle at the bottom of the reactor. In order to maintain the steady state operation of the bioreactor very large floc particles are regularly removed from the various outlets along the height of the reactor.

Special Features:

High rates of bioconversion due to high concentration of biomass; Excellent mixing characteristics due to fluidized nature of contents; Steady state of operation with constant biomass concentration; Steady state of operation with constant biomass concentration; Easy control of process because of withdrawal of solids at the bottom; Clarified liquid from the outlet

Prospective Users:

Domestic and Industrial waste water treatment plants

Keywords:

Waste water, Treatment, bioreactor

Type of Technology:

Process

Status of IPR Protection:

Indian Patent Application No. 1479/DEL/99 dated 15th January 2001 with title "An Improved Apparatus for carryingout Bio-reaction"

Status of Development:

Under the sponsorship of Dept. of Biotechnology, Govt. of India, studies were conducted in a 40 litre total volume reactor designed and fabricated in IIT, Delhi. Waste water from various sources like dairy effluents at different hydraulic and operating conditions were treated at the rate of 500 litres per day. Even at a very small hydraulic retention time of about 2 hours, the COD of the effluent was brought down from a value of about 1200 mg per litre to less than 100 mg per liter. This was accompanied by production of biogas containing 65% - 70% methane. The amount of methane produced was almost 300 titres (STP) per kg. of COD removed. The treated effluent had excellent sludge settling and dewatering characteristics also.

Major Equipment & Facilities required:

Reactor volume: 800 litres (approxly); Floor Area requirement : 4m x 4m

Services offered by Technology Transfer:

Know how manual including quality control procedures
Process demonstration
Consultancy

For further information please contact :

The Director
Foundation for Innovation and Technology Transfer
Indian Institute of Technology Delhi
Hauz Khas, New Delhi-110016
Tel : 91-011-26597167, 26857762, 26581013
Fax : 91-011-26851169
E-mail : mdfitt@gmail.com