The use of fluidized-bed bioreactors in waste and drinking water treatment has several advantages, the most significant of which is the specific removal rate, which is an order of magnitude higher than that of equivalent activated sludge processes. In this paper, the usual concept of nitrification-denitrification in separated units is replaced by a new concept in which the two processes are performed together in a single high-performance fluidized-bed. Based on the former nitrifying reactor, new equipment was designed. This reactor contained a fluidized bed with separated aerobic and anoxic sections for nitrification and denitri fication respectively. This was accomplished by the use of different-diameter sand as carrier material and appropriate reactor shape, recirculation, feed and aeration conditions. The reactor (20 L fluidized-bed volume) was operated for 3 months. It was fed with synthetic waste water (50 L/h) containing 25-40 mg NH4 +-N/L. Propionic acid and ethanol in a 1:4 ratio were used as the carbon source (2.3 g C/L) for deni trification, fed in at different points of the reactor. Ammonium removal reached 50%, while denitrification was 75%. The total nitrogen removal rate was 0.8-1.2 kg N/m 3.d. A new simple hydrostatic pressure method was used to monitor biofilm thickness in the fluidized bed. During the experiments the oxidation-reduc tion potential (ORP) was tested as a tool to monitor reactor performance; its use for the control of the process was found to be limited.

The use of fluidized-bed bioreactors in waste and drinking water treatment has several advantages, the most significant of which is the specific removal rate, which is an order of magnitude higher than that of equivalent activated sludge processes. In this paper, the usual concept of nitrification-denitrification in separated units is replaced by a new concept in which the two processes are performed together in a single high-performance fluidized-bed. Based on the former nitrifying reactor, new equipment was designed. This reactor contained a fluidized bed with separated aerobic and anoxic sections for nitrification and denitrification respectively. This was accomplished by the use of different-diameter sand as carrier material and appropriate reactor shape, recirculation, feed and aeration conditions. The reactor (20 L fluidized-bed volume) was operated for 3 months. It was fed with synthetic waste water (50 L/h) containing 25-40 mg NH4+-N/L. Propionic acid and ethanol in a 1:4 ratio were used as the carbon source (2.3 g C/L) for denitrification, fed in at different points of the reactor. Ammonium removal reached 50%, while denitrification was 75%. The total nitrogen removal rate was 0.8-1.2 kg N/m(3).d. A new simple hydrostatic pressure method was used to monitor biofilm thickness in the fluidized bed. During the experiments the oxidation-reduction potential (ORP) was tested as a tool to monitor reactor performance; its use for the control of the process was found to be limited.

A fluidized bed denitrifying reactor was run to examine the vertical segregation of sand particles on the basis of different biofilm coverage, so far neglected when modelling fluidized beds. The segregation was found to be significant and it can be directly correlated with the vertical hydrostatic pressure profile in the bed. A procedure was developed for the rapid determination of biofilm thickness from hydrostatic pressure data using a recently published method based on the use of the novel criteria “expansion coefficient” and “specific occupied volume”. A key feature of the procedure is the “particle content”, which can be calculated from particle characteristics and is correlated in this study with the hydrostatic pressure gradient. The method was verified by directly measuring biofilm thickness as a function of the vertical position in the bed. This way biofilm thickness can be calculated from a readily measurable hydrostatic pressure profile with an error of 0.04–0.06 mm. This error is believed to be due to N2 gas entrapment in the denitrifying biofilm and to the original inaccuracy of the determination of particle size and volume. The method is rather insensitive to the exact biofilm density when the usual high-density carrier material is used.

Biofilm processes are widely used; the most effective of these fluidized bed reactors, the design and modelling of which is still difficult. A fluidized sand bed denitrifying reactor was run to clarify contradictions in the applicability of the Richardson-Zaki model for the description of fluidization hydrodynamics and to determine fully the true biofilm parameters experimentally. Biofilm density was found to be 1.055 ±0.018 g/cm3. A fundamental parameter of the Richardson-Zaki model, the terminal settling Reynolds number, was found to be not characteristic of the particles. Consequently a new approach was developed for the description of biofilm-coated particle fluidization. The model is based on two new parameters: the ‘expansion coefficient’ and the ‘specific occupied particle volume at zero flow’, which are readily determinable and characteristic parameters of the fluidized particles, being independent of reactor size and shape, liquid velocity or of the quantity of carrier particles. The model is suitable for modelling bed porosity or biomass concentration as a function or the biofilm thickness and upflow liquid velocity. We found that there can be an optimal biofilm thickness above which not only can the diffusion limitation increase, but the overall biomass concentration decreases at a given liquid velocity.

Sunflower lecithin is an important product in countries producing large amounts of sunflower oil. Due to its high phosphatidylcholine and essential fatty acid contents, it can be well utilized as an additive in food and feedstuffs. After refinement and fractionation, its utilization in food products and cosmetics can be greatly increased and further extended after appropriate modification. Utilized as an additive in the feedstuff to piglets and porklings, it results in higher bodyweight and shortened breeding and fattening periods. It is also suitable for adjusting the energy level of broiler feeds and, owing to its choline content, the use of synthetic choline chloride can be eliminated.

The specific gas production rate for various anaerobic sludges was determined as a function of acetate concentration at 35°C and pH 7.0. Three substrate inhibition kinetic equations were fitted to experimental data by a non-linear regression method. The best description was reached with modified Haldane-type kinetics. Comparison of raw and granular sludges of different origin showed reduced sensitivity of granular sludges to substrate inhibition. A continuous experiment with molasses waste-water in an upflow anaerobic sludge blanket reactor gave similar results: substrate inhibition continuously decreased as granule development proceeded. by modification of the model real physical meaning was attributed to calculated kinetic parameters. This allowed more adequate comparison with data reported previously based on the equations of Monod and Andrews. Our results are of the same magnitude as previously reported data.

Several types of high organic matter pollutants containing (COD-range: 3-50 kg.m-3) industrial waste waters were treated in laboratory scale (1.2-23 dm3) sludge blanket (UASB) and UASB-fixed bed hybrid (UBF) reactors. In most cases higher than 80% of COD-removal efficiency has been attained. The CO2 content of the biogas developed was mainly influenced by the neutralization (base to acid) ratio related to feed pH.Cell immobilization by granule formation was considered as a change in microbial population: enrichment and aggregate formation of Methanotrix-like filamentous microorganisms. Based on physiological and physical indexes of microbial selection and with regard to the different sensitivities of microorganisms to substrate inhibition, a new start-up method was developed for rapid (40-45 days) granulation of raw digested sludge.

AbstractRecent results are surveyed concerning the average conformation of starch polysaccharides in solution. Special regard is given to possible detection of helical segments by high resolution NMR spectroscopy combined with theoretical energy calculations.

The development of granular sludge in laboratory-scale upflow anaerobic sludge-blanket reactors was studied. Acetate was supplied as sole carbon source in order to select the acetotrophs Methanosarcina and Methanothrix. These microorganisms are dominant in methanogenic ecosystems and their ratio seems to control the speed of granulation. Changing the ratio of the above species was followed on the basis of their different F420-coenzyme content. Five reactors were operated at the same hydraulic retention time but at different feed substrate concentrations. We found that granulation takes place only in acetate-fed systems but this process was slower and the resultant granules looser and less stable than those developed on sugar-starch substrate. In the range of feed acetate levels examined (0.5−0.3 g/1) higher concentrations of feed caused faster granulation of the sludge bed and, presumably, of the microbial population, and resulted in larger granules containing sludge that settled more readily. We found no evidence for selection pressure at substrate concentrations below 0.5 g/1 acetate in the reactor.

If the wastewater to be treated contains various forms of nitrogen, three biological treatment steps are required for nitrogen removal: (a) in a bio-oxidation step, organic nitrogen is anerobically broken down to ammonia nitrogen; (b) in a subsequent nitrification step, ammonia nitrogen in the wastewater is aerobically converted to nitrate nitrogen; and (c) in a final denitrification step, nitrate nitrogen is anaerobically or anoxically converted to nitrogen gas. This chapter discusses bio-oxidation, nitrification and denitrification process steps, their principles, and design considerations in detail.

AbstractComputer graphics with energy‐minimalization incorporated as a tool in a Biomolecular Program (BMP) helps to develop three‐dimensional structure models for starch components in order to understand the role of conformation in solutions.

AbstractSunflower contains, in addition to oil, considerable amount of protein, therefore, a very important aspect in processing sunflowerseeds is to obtain high quality, well utilizable meal. The quality of meal is mainly dependent on hull content and consistency and these two factors can be favourably changed by dehulling techniques and special treatment. On the basis of average data in Hungary, without dehulling, hull content of the meal was 46–48%, as a result of a dehulling technique developed by the industry, however hull content dropped to 20–22%, thus, min. 40% protein content has been attained, In the course of the efficient technology, dehulling is carried out in dehulling drums operating on the principle of the beating and/or centrifugation adjusted to seed quality, and separation of the hull and kernel is gradually performed by size‐gradign and aspiration. With a view to minimum loss of oil, the huge amounts of selected hulls are passed through a hull‐cleaning device, then burned in special hull‐burning boilers, thus utilizing its energy for the generation of steam. In our experience, the feeding of monogastrics, especially of young animals requires even higher standards of meal quality than described above, where hull consistency in the meal can be favourably changed by chemical and/or mechanical treatment. Thus, in the rearing and finishing feeds of broilers, 50‐75% of the soybean can be satisfactorily replaced by the above sunflower meal, supplemented by lysine, and can be favourably utilized as a fodder product for pigs, as well.

AbstractDer Verfasser gibt in seinem Festvortrag einleitend einen Überblick über die Weltproduktion von Ölsamen, die in den letzten Jahren stark angestiegen ist. Die Produktionsdaten der wichtigsten Ölpflanzen werden angegeben. Im Anschluß daran werden die Aufarbeitungstechnologien für Ölpflanzen in der Vergangenheit und die heutigen industriellen Verfahren und Trends (optimale Betriebsgröße, spezielle Betriebe, Senkung der Betriebskosten, Qualitätsverbesserung der Produkte, Ausbildung des Personals, Arbeitsschutz) umfassend behandelt. Bei den technologischen Schritten der Aufarbeitung von Ölsamen werden die Entwicklungstendenzen des Transports, der Übernahme, Lagerung und Reinigung der Rohstoffe, der Entschalung der ölhatigen Samen, der vorbereitenden Operationen zur Ölgewinnung, Konditionierung und Pressung sowie der Extraktion von Ölsamen mit Lösungsmitteln im einzelnen aufgezeigt. Weiterhin werden die Trends in der meß‐ und regeltechnischen Ausrüstung der Anlagen ausführlich dargelegt und Energiewirtschaftsfragen bei der Aufarbeitung von Ölsamen besprochen. Abschließend werden die Möglichkeiten der Qualitätsverbesserung von Futterschrot behandelt.

In steady state, attained by continuous aeration after oxygen saturation of water in a bubble column, vertical composition distribution of liquid and gas phases has been determined. It has been assumed that, as a result of absorption at the bottom of the column, desorption in the upper section and vertical dispersion of dissolved oxygen flux, a closed oxygen circulation is created. Determination of the axial dispersion coefficient from hydrodynamic and oxygen transfer data verifies the mathematical model proposed. The results allow conclusions to be drawn about supersaturation and desorption and other phenomena expected in biological systems.

AbstractComputer aided molecular modelling has been used to study the solution‐conformation of various complexes of amylose. The preferred conformation of the complexes is determined by the HSEA Hard‐Spheres Exo‐Anomeric effect) method using the interactive computer program CAOS (Conformational Analysis of Oligosaccharides). NMR spectroscopy (nOe experiments, relaxation time measurements and the observation of local shielding) can follow and prove the conformation changes in solution.