A process for denitrifying a highly nitrogenous wastewater in the presence of high concentrations of ammonia is described. The process is based on upflow packed bed and fluidized bed reactors containing denitrifiers on the packing material. A carbon source, e.g. molasses, is metered into the wastewater as a source of carbon and energy to the bacteria. Excess bacteria are removed by hydraulic shear.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. application Ser. No. 806,166, filed June 13, 1977 now abandoned, which is incorporated by reference herein. Said prior application is directed to a method of denitrifying a strongly nitrogenous effluent, wherein the nitrogen content exceeds 150 mg/l, comprising charging a packed reactor with denitrifying bacteria, being heterotrophic and facultative anaerobes, and passing the effluent mixed with a predetermined amount of a carbon source at a predetermined flow rate through the reactor, the flow rate, amount of carbon source and reactor and process variables being selected for a desired denitrification of the effluent.
The use of plant suspension cultures to remove ionic metallic species and TNT-based explosives and their oxidation products from aqueous solution is described. Several plant strains were investigated including D. innoxia, Citrus citrus, and Black Mexican Sweet Corn. All showed significant ability to remove metal ions. Ions removed to sub-ppm levels include barium, iron, and plutonium. D. innoxia cells growing in media containing weapons effluent contaminated with Ba.sup.2+ also remove TNT, other explosives and oxidation products thereof from solution. The use of dead, dehydrated cells was also found to be of use in treating waste directly.
In a process for the production and maintenance of well-adhering biomass attached to carrier particles capable of decomposing contaminants in waste water containing both well-adhering and non-adhering microorganisms wherein a granular carrier is contacted in a reaction space with a continuous stream of waste water containing both well-adhering and non-adhering microorganisms and nutrients for the growth and the maintenance of the microorganisms in an adherent layer until a sufficiently thick, well-adhering layer of microorganisms is formed and maintained on the carrier, the improvement comprising maintaining the residence time of the waste water in the reaction space lower than the reciprocal maximum growth rate of the microorganisms on carrier particles of at least 0.1 mm while generating in the reaction liquid shear forces caused by liquid motion and circulation caused by gas bubbles and washing out of the reaction space all non-adhering microorganisms. The process can be used for the production of high amounts per cubic meter of reactor volume of all kinds of biomass attached to a carrier, e.g. biomasses as are applied in the biological purification of waste water, aerobic biomass, anaerobic biomass, nitrifying biomass and denitrifying biomass, as well as biomasses forming a desired metabolic product which inhibits its own production rate at higher concentrations, e.g. biomass for the production of alcohol.
A system for the anaerobic bacterial degradation of organic material in waste water, comprising introducing the waste water into a contact reactor, pumping the waste water into the bottom of a fluidized bed reactor containing anaerobic bacteria attached to the particles in the bed, the fluidized bed reactor having an effective volume not more than 0.35 times the effective volume of the contact reactor, returning the waste water which has passed through the fluidized bed reactor to the contact reactor and continuously or discontinuously removing treated effluent from the system. A start-up procedure for the anaerobic treatment system is described comprising culturing anoxic bacteria in the system by adding nitrate ions to the waste water and gradually reducing the amount of nitrate ions in the stream until the population of anoxic bacteria is substantially replaced by a population of anaerobic bacteria. A viable microbial population is established in both the fluidized bed reactor and the contact reactor.
In a denitrification process wherein denitrifying agents are supported on a carrier material, the invention comprises conducting denitrification in the presence of a carrier impregnated with an organic substance capable of serving as a reducing agent for the denitrifying agents. In another aspect the invention relates to a method of preparing such a carrier and to the carrier itself.
In a process for the production and maintenance of well-adhering biomass attached to carrier particles capable of decomposing contaminants in waste water containing both well-adhering and non-adhering microorganisms wherein a granular carrier is contacted in a reaction space with a continuous stream of waste water containing both well-adhering and non-adhering microorganisms and nutrients for the growth and the maintenance of the microorganisms in an adherent layer until a sufficiently thick, well-adhering layer of microorganisms is formed and maintained on the carrier, the improvement comprising maintaining the residence time of the waste water in the reaction space lower than the reciprocal maximum growth rate of the microorganisms on carrier particles of at least 0.1 mm while generating in the reaction liquid shear forces caused by liquid motion and circulation caused by gas bubbles and washing out of the reaction space all non-adhering microorganisms. The process can be used for the production of high amounts per cubic meter of reactor volume of all kinds of biomass attached to a carrier, e.g. biomasses as are applied in the biological purification of waste water, aerobic biomass, anaerobic biomass, nitrifying biomass and denitrifying biomass, as well as biomasses forming a desired metabolic product which inhibits its own production rate at higher concentrations, e.g. biomass for the production of alcohol.
