Behaviour of biodegradable plastics in composting facilities.

Composting is a preferred treatment strategy for biodegradable plastics (BDPs). In this sense, the collection of BDPs together with organic household wastes is a highly discussed possibility. Under the aspect of the behaviour of BDPs in composting facilities, a telephone survey was carried out with selected composting facility operators.

Reproduction of the estuarine and marine amphipod Corophium volutator (Pallas) in laboratory for toxicity testing.

The acute whole sediment bioassay with the estuarine and marine amphipod Corophium volutator (Pallas) is broadly used within Europe. Hitherto, the test is carried out with field-collected animals. In order to provide a more standardized and continuously available test organism reproduction and growth experiments were performed for a period of one year in laboratory under simulated summer conditions (light/dark 16:8 at 15, 19, and 23 degrees C).

Cloning, sequencing, and characterization of a heat- and alkali-stable type I pullulanase from Anaerobranca gottschalkii.

The gene encoding a type I pullulanase was identified from the genome sequence of the anaerobic thermoalkaliphilic bacterium Anaerobranca gottschalkii. In addition, the homologous gene was isolated from a gene library of Anaerobranca horikoshii and sequenced. The proteins encoded by these two genes showed 39% amino acid sequence identity to the pullulanases from the thermophilic anaerobic bacteria Fervidobacterium pennivorans and Thermotoga maritima.

Greywater treatment by constructed wetlands in combination with TiO2-based photocatalytic oxidation for suburban and rural areas without sewer system.

In this study greywater treatment through constructed wetlands and subsequently through TiO2-based photocatalytic oxidation was investigated. Through constructed wetlands treatment the organic substances have been reduced greatly. For further removal of organic substances and pathogens, a TiO2-based photocatalytic oxidation process was used subsequently.

Microbial oxidation of methane from old landfills in biofilters.

Landfill gas emissions are among the largest sources of the greenhouse gas methane. For this reason, the possibilities of microbial methane degradation in biofilters were investigated. Different filter materials were tested in two experimental plants, a bench-scale plant (total filter volume 51 l) and a pilot plant (total filter volume 4 m3).

Investigation and optimization of composting processes-test systems and practical examples.

To determine the optimal course of composting it is useful to carry out experiments. The selection of the right experimental set-up depends on the question of concern. Each set-up is useful for a particular application and has its limits.

Polishing of secondary effluent by an algal biofilm process.

The potential in polishing secondary effluent by an algal biofilm composed of different green and bluegreen algae was investigated. During the photosynthesis process of algal biofilm oxygen was produced while dissolved carbon dioxide was consumed. This led to an increasing pH due to the change of the carbon dioxide equilibrium in water.

Early warning-system for operation-failures in biological stages of WWTPs by on-line image analysis.

By the observation and evaluation of the microscopic picture of activated sludge samples it is possible to introduce another biological parameter additional to conventional physico-chemical parameters for the control of biological stages of waste water treatment plants. Considering the fact that parameters like floc size and floc size distribution, structure of the flocs (compact/open), shape of the flocs (round/irregular) allow perceptions of the adjusted operation conditions of the biological stages, evidence for changing operation conditions or threatening operation disturbances can be recognised. This recognition takes place at a very early phase, because the morphology of activated sludge flocs reacts very fast to changing conditions.

A new rechargeable dialysis pore water sampler for monitoring sub-aqueous in-situ sediment caps.

A new rechargeable dialysis pore water sampler is proposed that is adapted to the requirements of monitoring in-situ sediment remediation techniques, in particular in-situ capping. Sampling and recharging of the sampler can be carried out from a boat or a pontoon by means of separate tubing and a peristaltic pump. The possibility of repeated sampling permits a temporal as well as a spatial resolution of pore water geochemistry.

Evaluation of a leaching process coupled with regeneration/recycling of the extractant for treatment of heavy metal contaminated solids.

A hydrometallurgical circuit process combining the leaching of metals with the electrolytic regeneration of the mass separating agent is an option to effectively treat heavy metal contaminated solids. This process aims towards a dosed loop utilisation of the extractant by its regeneration and recycling, enabling the use of high cost extractants and the recovery of the heavy metals as well. The circuit process, in which each cycle consists of an extraction step followed by the electrolytic regeneration of the mass separating agent and a second extraction to finally recycle the separating agent and start a new cycle, was applied on a lead contaminated soil from an accumulator manufacturing facility and for the removal of copper from a municipal solid waste incinerator bottom ash.

The evolution of the biotechnology industry in Germany.

In the past five years, the climate for commercial biotechnology in Germany has improved significantly and has resulted in an increase in the number of biotechnology companies. On examination of the underlying factors of the evolution of the biotechnology industry in Germany, and against the background of the current situation, it is predicted that many German biotech companies will have to change their business models to focus on product development rather than on platform technologies.

Effect of glucose, maltose, soluble starch, and CO2 on the growth of the hyperthermophilic archaeon Pyrococcus furiosus.

The hyperthermophilic archaeon Pyrococcus furiosus was cultivated in batch and continuous fermentations on different carbon substrates. The cultivation of P furiosus on soluble starch as the only carbon source resulted in cell densities three times higher than in cultivations on maltose, 1.06 x 10(10) cells/ml compared to 3.

Options for alternative types of sewerage and treatment systems directed to improvement of the overall performance.

Technology for future houses may well include a high-tech water recycling unit that makes tapwater while people drink bottled water of high quality. There may be toilets that produce just a bag of dry fertiliser per year, hopefully without fossil energy. Rainwater infiltration is increasingly replacing storm sewers anyway.

Impact of natural nanophases on heavy-metal retention in zeolite-supported reactive filtration facilities for urban run-off treatment.

The retention of lead in zeolite-supported sand-filter columns has been tested with focus on the effect of potentially mobile natural nanophases (natural colloids, humic substances). It could be shown that interaction of lead with natural nanophases enhanced the mobility of the contaminant. In the presence of iron oxide particles (goethite) a normal breakthrough of lead was observed.

Removal of chlorinated pollutants by a combination of ultrasound and biodegradation.

Chlorinated organic compounds are hazardous pollutants found in waste water, surface water, and ground water. Our study shows that a combination of ultrasonic pretreatment and biodegradation effectively removes the solvent chlorobenzene and the disinfectant 2,4-dichlorophenol, also reduces Adsorbable Organic Halogens (AOX) and Chemical Oxygen Demand (COD). In our experiments, the ultrasonic dechlorination was not influenced by the presence of other soluble organic compounds like acetate or glucose.

Ultrasonic waste activated sludge disintegration for improving anaerobic stabilization.

The pretreatment of waste activated sludge by ultrasonic disintegration was studied in order to improve the anaerobic sludge stabilization. The ultrasound frequency was varied within a range from 41 to 3217 kHz. The impact of different ultrasound intensities and treatment times was examined.

Contaminants in sediments: remobilisation and demobilisation.

In this study, the contaminated anoxic sediment of the Mulde reservoir (Saxony, Germany) was investigated. Several sediment cores were analysed for heavy metals and organic chemicals such as chlorobenzenes and DDTs. The comparison between anoxic and oxidised sediment cores showed the potential danger for heavy metal (Zn and Cd) remobilisation from sediment due to bioturbation or resuspension by flooding.

Modeling of three-dimensional pressure fields in sonochemical reactors with an inhomogeneous density distribution of cavitation bubbles. Comparison of theoretical and experimental results.

During the last 50 years extensive experimental investigation has been carried out on the chemical effects of ultrasound, but limited work has been reported on modeling. This paper presents a new model in which a numerical calculation of the three-dimensional linear sound pressure field distribution in a commonly used sonoreactor containing three transducers is carried out. In this model the inhomogeneous three-dimensional time-dependent wave equation was solved using the finite difference approach.

Stability of immobilized soybean lipoxygenases: influence of coupling conditions on the ionization state of the active site Fe.

The potential application of lipoxygenase as a versatile biocatalyst in enzyme technology is limited by its poor stability. Two types of soybean lipoxygenases, lipoxygenase-1 and -2 (LOX-1 and LOX-2) were purified by a two step anion exchange chromatography. Four different commercially available supports: CNBr Sepharose 4B, Fractogel((R)) EMD Azlactone, Fractogel((R)) EMD Epoxy, and Eupergit((R)) C were tested for immobilization and stabilization of the purified isoenzymes.

The relative importance of intracellular proteolysis and transport on the yield of the periplasmic enzyme penicillin amidase in Escherichia coli*.

Intracellular proteolysis is an important mechanism for regulating the level of the periplasmic enzyme penicillin amidase in Escherichia coli. Evidence is presented that the active enzyme is localized in the periplasmic space and maturation of pro-enzyme occurs during transport through the cytoplasmic membrane or rapidly after its entrance in the periplasm. The rate constants of the transport through cytoplasmic membrane and of the intracellular proteolysis were estimated to be 0.

pH dependence of penicillin amidase enantioselectivity for charged substrates.

The pH dependence of E (enantiomeric ratio or enantioselectivity, a quantitative measure for enzyme stereospecificity) was studied for penicillin amidase catalysed hydrolysis of charged enantiomeric substrates. Theoretical analysis shows that a pH dependence can only be observed around the pK values of groups in the active site whose ionisation control the enzyme activity. For charged substrates that may perturb these pK values, a pH dependence of E is also expected.

Purification and characterization of thermostable pectate-lyases from a newly isolated thermophilic bacterium, Thermoanaerobacter italicus sp. nov.

A novel thermophilic spore-forming anaerobic microorganism (strain Ab9) able to grow on citrus pectin and polygalacturonic acid (pectate) was isolated from a thermal spa in Italy. The newly isolated strain grows optimally at 70 degrees C with a growth rate of 0.23 h(-1) with pectin and 0.