Showing papers in "Water Science and Technology in 1994"

TL;DR: A survey over the capabilities of a new simulation and data analysis program for laboratory, technical and natural aquatic systems is given that provides methods for system identification (sensitivity analysis and automatic parameter estimation) and allows us to estimate the uncertainty of calculated results.

TL;DR: Macrophytes stabilise the surface of the beds, provide good conditions for physical filtration, prevent vertical flow systems from clogging, insulate against frost during winter, and provide a huge surface area for attached microbial growth.

TL;DR: In this paper, a new moving bed biofilm reactor has been developed in Norway, where the biomass is attached to carrier elements that move freely along with the water in the reactor.

TL;DR: In this article, the authors summarized the state-of-the-art of the uses of constructed wetlands in water pollution control by reviewing the basics of the technology, the historical development, and the performance expectations with focus on the use of free water surface and subsurface flow constructed wetlands for municipal wastewater treatment.

TL;DR: It was observed that the amount of excess sludge is reduced to nearly zero when 1.2 kg/m 3 -aeration tank volume of biomass is recirculated in a day from the biological stage to the ozonation stage at a BOD loading of 1.0 kg/ m 3 /d.

TL;DR: In this article, the ozone treatment of textile wastewaters in combination with inexpensive biological processes has the potential to play a major role in the future, and partial replacement of coagulation/precipitation can be expected.

TL;DR: It could be concluded that a reduction of the phosphorus release by nitrate in biological phosphorus removal systems is partly due to the presence of DPB, which utilize HAc for denitrification, not for phosphorus release.

TL;DR: Case histories of systems that use alternating shallow and deep water zones to create both environments are presented and regression analysis of N removal and N loadings in 18 shallow-deep water systems suggested that NH 4 + loading could be used to predict effluentNH 4 + values.

TL;DR: A mathematical model has been formulated describing the reduction of nitrate, nitrite, and nitrous oxide and estimated parameters indicate that nitrite serves mainly as a denitrification intermediate rather than as an inhibitor.

TL;DR: Experiments with various imposed wasting rates showed that viability and sludge production yield decreased when sludge age increased and this work gives a new outlook on the AS process and leads to the development of processes with control and reduction ofSludge production.

TL;DR: In this paper, microbial metabolism in the activated sludge of a failed enhanced biological phosphorus removal process was investigated to clarify the cause of the failure, indicating that the dominant microorganisms in the sludge consumed carbohydrates in the uptake process of acetate or propionate under anaerobic conditions.

TL;DR: The microstructure of three types of UASB granules respectively treating sucrose, glutamate and brewery wastewaters in mesophilic conditions were analyzed, and the acetoclastic Methanothrix was found as the key structural element in all the granules, suggesting that it plays an important role in granulation.

TL;DR: In this paper, a novel methodology is proposed to estimate the adhesion strength of biofilm developed in an attached-growth reactor, where the time variation of adhesion strengths was quantified in the course of formation of a biofilm consisting of denitrifiers, and a strong correlation was observed between the dry density and the extracellular biopolymer content per unit biofilm volume.

TL;DR: In the paper this postulate is examined and disproved based on real operational data from of full-scale mesophilic and thermophilic biogas plants, finding the start-up procedure was, however, found to be crucial for determining the period needed before full capacity of the thermophile plant could be achieved.

TL;DR: Ethanol was found to be considerably more readily available as a carbon source for denitrification than was methanol, and an efficient denitrify with ethanol was established in a short time, while den itrification with meethanol required a substantial adaptation time and never showed the same stability as denitrified with ethanol.

TL;DR: Chemostat experiments demonstrated that both nitrifiers produce SMP that can support heterotrophic bacteria, and preliminary kinetic analysis suggested that SMP kinetic parameters can be adapted from parameters measured for heterotrophs.

TL;DR: The effect of pH on the adsorption isotherm was investigated at pH values of 4, 6, 7, 8, 10 and 12 in a batch adsorber as mentioned in this paper.

TL;DR: In this article, the ozone colour removal plant at Leek S.T.W. is described and early operating data is given, but compliance with the consent has been 89.7% and not the 100% required.

TL;DR: Temperature is a key parameter in the nitrification process producing two opposite effects: bacteria activation and free ammonia inhibition, and knowledge of this threshold in a biofilm process is fundamental in order to control the nitrite accumulation in nitrifying biofilm reactors.

TL;DR: In this article, constructed wetlands are categorized into two types: free water surface flow or subsurface flow, and design criteria are set out for both types and operational details are given for both municipal wastewater treatment plants.

TL;DR: A comparison between the different biofilm processes and activated sludge alternatives showed that biofilm systems may lead to remarkably smaller reactor volumes, but high energy consumption due to unfavorable oxygen utilization.

TL;DR: In this article, both aerobic and anaerobic processes can be incorporated into the final design of a wetland treatment system for trace metal removal, and the results showed that both processes can successfully treat neutral drainage in overland flow systems.

TL;DR: In this paper, the respiration rate determinations used for the bi- or tri-substrate determinations are coupled to removal capacity in order to develop rate-capacity diagrams, that give a fuller picture of the wastewater and its influence on the biological processes.

TL;DR: In this article, an algorithm was developed based on equilibrium chemistry to quantitatively predict the struvite precipitation potential of the water in such a process and then extended to predict the change in state together with precipitation potential due to chemical perturbations, particularly variations of p CO 2.

TL;DR: In this paper, the authors investigated the granule development in IC-reactors and elucidated the process limitations with respect to granules development and biomass retention. But, the results showed that IC granules are larger than UASB-granules grown on similar wastewater, while the strength of ICgranules is lower as a result of the higher sludge loading rate.

TL;DR: In this paper, the importance of decaying plant material, in a floating mat of the wetland plant Glyceria maxima, as a source of organic carbon and anoxic sites for denitrification in surface-flow wetlands was investigated.

TL;DR: In this paper, the upflow Staged Sludge Bed (USSB) was used for thermophilic anaerobic treatment of acidified and partially acidified wastewater using upflow staged sludge bed (usSB) reactors.

TL;DR: In this article, the monitoring of a dozen medium capacity (7,500 to 150,000 p.m.) plants designed to treat organic pollution, has enabled the authors to evaluate the process and its performance and the results obtained show that at applied loads of less than 7 kg of COD, the effluent is of satisfactory quality.

TL;DR: Experiments showed that competition in biofilms resulted in non-uniform spatial distributions of bacterial populations and metabolically active bacteria, which affected the substrate transfer and substrate competition within the biofilm.

TL;DR: Highly hydrophobic bacteria coexist in the flocs with highly hydrophilic bacteria which seem to release large quantities of exopolymers which increases both exopolymer production and the sludge volume index.