A review on anaerobic-aerobic treatment of industrial and municipal wastewater.

Nitrification with high nitrite accumulation for the treatment of wastewater with high ammonia concentration.

In a membrane bioreactor (MBR), fast growth of anammox bacteria was achieved with a sludge residence time (SRT) of 12 days. This relatively short SRT resulted in a—for anammox bacteria—unprecedented purity of the enrichment of 97.6%. The absence of a selective pressure for settling, and dedicated cultivation conditions led to growth in suspension as free cells and the complete absence of flocs or granules. Fast growth, low levels of calcium and magne- sium, and possibly the presence of yeast extract and a low shear stress are critical for the obtainment of a completely suspended culture consisting of free anammox cells. During cultivation, a population shift was observed from Candida- tus ''Brocadia'' to Candidatus ''Kuenenia stuttgartiensis.'' It is hypothesized that the reason for this shift is the higher affinity for nitrite of ''Kuenenia.'' The production of ana- mmox bacteria in suspension with high purity and produc- tivity makes the MBR a promising tool for the cultivation and study of anammox bacteria. Biotechnol. Bioeng. 2008;101: 286-294. 2008 Wiley Periodicals, Inc.

/pdf/the-membrane-bioreactor-a-novel-tool-to-grow-anammox-4ryzg1op0v.pdf

The membrane bioreactor: a novel tool to grow anammox bacteria as free cells.

Wastewater treatment with particulate biofilm reactors

In this article, the conditions for aerobic biofilm formation on suspended particles, the dynamics of biofilm formation, and the biomass production during the start-up of a Biofilm Airlift Suspension reactor (BAS reactor) have been studied. The dynamics of biofilm formation during start up in the biofilm airlift suspension reactor follows three consecutive stages: bare carrier, microcolonies or patchy biofilms on the carrier, and biofilms completely covering the carrier. The effect of hydraulic retention time and of substrate loading rate on the formation of biofilms were investigated. To obtain in a BAS reactor a high biomass concentration and predominantly continuous biofilms, which completely surround the carrier, the hydraulic retention time must be shorter than the inverse of the maximum growth rate of the suspended bacteria. At longer hydraulic retention times, a low amount of attached biomass can be present on the carrier material as patchy biofilms. During the start-up at short hydraulic retention times the bare carrier concentration decreases, the amount of biomass per biofilm particle remains constant, and biomass increase in the reactor is due to increasing numbers of biofilm particles. The substrate surface loading rate has effect only on the amount of biomass on the biofilm particle. A higher surface load leads to a thicker biofilm.A strong nonlinear increase of the concentration of attached biomass in time was observed. This can be explained by a decreased abrasion of the biofilm particles due to the decreasing concentration of bare carriers. The detachment rate per biofilm area during the start-up is independent of the substrate loading rate, but depends strongly upon the bare carrier concentration.The Pirt-maintenance concept is applicable to BAS reactors. Surplus biomass production is diminished at high biomass concentrations. The average maximal yield of biomass on substrate during the experiments presented in this article was 0.44 +/- 0.08 C-mol/C-mol, the maintenance value 0.019 +/- 0.012 C-mol/(C-mol h). The lowest actual biomass yield measured in this study was 0.15 C-mol/C-mol.

Formation and growth of heterotrophic aerobic biofilms on small suspended particles in airlift reactors.

A simple hydrodynamic model for the liquid circulation velocity in a full-scale two- and three-phase internal airlift reactor operating in the gas recirculation regime

Large Scale Anaerobic-Aerobic Treatment of Complex Industrial Waste Water Using Biofilm Reactors

Results are presented on pilot and full-scale pretreatment of industrial wastewater in an anaerobic 2-stage fluidized bed reactor for CH 4 -production and laboratory and pilot scale post-treatment of the anaerobic effluent, which contains NH 4 + and HS − in an aerobic air-lift suspension reactor for the production of NO 3 − and SO 4 2−

Large‐scale anaerobic/aerobic treatment of complex industrial wastewater using immobilized biomass in fluidized bed and air‐lift suspension reactors

Reduction of the hysteresis effects in a gaslift loop reactor is effected with a draft tube for solids suspension. The gas or liquid flow rates for generating complete solid suspension are significantly higher than the flow rates necessary for maintaining that state. These hysteresis effects may be significantly reduced and a substantial reduction is obtained for the energy necessary to obtain the state of suspension. Preferably a draft tube which comprises openings through which an extra circulation takes place especially during the startup phase is used.

Startup openings in a three-phase gaslift loop reactor

A draft tube (4) which comprises openings (1) through which an extra circulation takes place especially during the startup phase to be used for reducing the hysteresis effects in an air lift reactor for solids suspension.

Rene Weltevrede

Papers

A simple hydrodynamic model for the liquid circulation velocity in a full-scale two- and three-phase internal airlift reactor operating in the gas recirculation regime

Large Scale Anaerobic-Aerobic Treatment of Complex Industrial Waste Water Using Biofilm Reactors

Large‐scale anaerobic/aerobic treatment of complex industrial wastewater using immobilized biomass in fluidized bed and air‐lift suspension reactors

Startup openings in a three-phase gaslift loop reactor

Process for reducing the hysteresis effect in a gaslift loop reactor with suspended solid particles