Gist-Brocades N.v.

Biothane Corporation

Grontmij Advies & Techniek B.v.

Joseph Johannes Heijnen

Pieter A Lourens

Robert J Zoetemeyer

Wilhelmus Antonius Koevoets

Marinus Cornelis Van Loosdrecht

Marinus Cornelius Maria Van Loosdrecht

Albertus J Vixseboxse

Albert J Vroemen

Cornelis P Venema

Abraham Antonius Keijzers

Willem Adolf Enger

Robert Jan Zoetemeyer

A method is described for the biological treatment of ammonium-rich wastewater in at least one reactor which has a temperature of at least 25&deg; C., which involves the wastewater being passed through the said reactor(s) with a population, obtained by natural selection in the absence of sludge retention, in the suspended state of nitrifying and denitrifying bacteria to form, in a first stage with the infeed of oxygen, a nitrite-rich wastewater and by the nitrite-rich wastewater thus obtained being subjected, in a second stage without the infeed of oxygen, to denitrification in the presence of an electon donor of inorganic or organic nature, in such a way that the contact time between the ammonium-rich wastewater and the nitrifying bacteria is at most about two days, and the pH of the medium is controlled between 6.0 and 8.5 and the excess, formed by growth, of nitrifying and denitrifying bacteria and the effluent formed by the denitrification are extracted. In addition the growth rate of the nitrifying and denitrifying bacteria is expediently controlled by means of the retention time, in the reactor, of the wastewater to be treated which is fed in.

Biological treatment of wastewater

A method is described for the biological treatment of ammonium-rich wastewater in at least one reactor which has a temperature of at least 25.degree. C., which involves the wastewater being passed through the said reactor(s) with a population, obtained by natural selection in the absence of sludge retention, in the suspended state of nitrifying and denitrifying bacteria to form, in a first stage with the infeed of oxygen, a nitrite-rich wastewater and by the nitrite-rich wastewater thus obtained being subjected, if required, in a second stage without the infeed of oxygen, to denitrification in the presence of a carbon source such as methanol, in such a way that the contact time between the ammonium-rich wastewater and the nitrifying bacteria is at most about two days, and the pH of the medium is controlled between 6.5 and 8.5 by the infeed of the said carbon source, and the excess, formed by growth, of nitrifying and denitrifying bacteria and the effluent formed by the denitrification are extracted, the demand for the said carbon source during the treatment being controlled as a function of the amount of heat produced in the reactor. In addition the growth rate of the nitrifying and denitrifying bacteria is expediently controlled by means of the retention time, in the reactor, of the wastewater to be treated which is fed in.

The invention relates to a three phase separator which comprises a compartment for the substantial separation of the gas-phase, this compartment being equipped with at least one partition which is applied for an internal gaslift circulation.

Three-phase separator for a fluidized bed apparatus

Fluidized-bed apparatus

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.

Process for preparing biomass attached to a carrier

A single unit fluidized-bed reactor having a reaction space for purification of waste water with biomass attached to carrier particles, comprising a liquid distribution device above the bottom of the reaction space particularly suited for introduction of waste water in wide reactors to achieve uniform fluidization therein, said device consisting of a number of substantially horizontal pipes, each having in the under-surface a number of regularly distributed openings for downward introduction of the liquid, and on top of the reaction space united therewith a multifunctional separation compartment for complete separation of the gas-liquid-solids mixture leaving the reaction space and for complete return of attached biomass into the reaction space, the separation compartment being construction so as to handle treatments involving large or small gas fractions in reactors of varying width.

Fluidized bed reactor

An oxidative biological purification process for waste water in a fluidized-bed reactor at a pH between 5 and 8 in the oxidation space comprising passing waste water upwards through an air-sparged oxidation space containing aerobic biomass attached to insoluble carrier particles of a size of 0.1 to 2 mm with a specific gravity of 2 to 5 g/cm.sup.3 at such a rate that space loads of COD of 4-50 kg/m.sup.3 day are achieved while continuously and completely separating purified waste water leaving the oxidation space from said attached aerobic biomass, whereby the aerobic biomass prevails to at least a very substantial extent in a state of attachment to said carrier particles, undue surplus formation of said sludge being minimized by continuous control of the residence time of the waste water to be treated in the oxidation space between the limits of 0.3 to 20 hours, and at least all attached aerobic biomass is recycled to the oxidation space by way of settling. Preferred embodiments include placing of a relatively smaller settling tank above the oxidation space, the use of sand as carrier material, gas and liquid flows being the only sources for stirring applied continuously, and purification at a temperature of 30.degree.-50.degree. C. The process gives a reliable waste water purification at a low level of surveillance even when considerable variations occur in the supply of COD and in the pH of the waste water introduced.

Growing community of inventors

Rijen, Netherlands

Joseph Johannes Heijnen