Biomedical subjects

Hardy Temmink

Publications and source records attributed to Hardy Temmink.

5 recordsLinked to original sources

PubMed2006

A new reactor concept for sludge reduction using aquatic worms.

Biological waste water treatment results in the production of waste sludge. The final treatment option in The Netherlands for this waste sludge is usually incineration. A biological approach to reduce the amount of waste sludge is through predation by aquatic worms. In this paper we test the applicability of a new reactor concept for sludge reduction by the aquatic worm Lumbriculus variegatus. In this reactor concept the worms are immobilized in a carrier material. In sequencing batch experiments, the sludge breakdown in the predation reactor is compared to sludge breakdown in a blank reactor (i.e. without worms). Predation by the worms results in a distinct sludge reduction, which is almost three times higher than in the blank experiment. The worm faeces that are produced after sludge predation have a sludge volume index (SVI) that is approximately half that of the initial waste sludge. Due to the configuration of the predation reactor, waste sludge, worm faeces and worms are separated, which is beneficial to further processing. The obtained results show that the proposed reactor concept has a high potential for use in large-scale sludge processing.

Animals↗

PubMed2005

Fate and biodegradability of sulfonated aromatic amines.

Ten sulfonated aromatic amines were tested for their aerobic and anaerobic biodegradability and toxicity potential in a variety of environmental inocula. Of all the compounds tested, only two aminobenzenesulfonic acid (ABS) isomers, 2- and 4-ABS, were degraded. The observed degradation occurred only under aerobic conditions with inocula sources that were historically polluted with sulfonated aromatic amines. Bioreactor experiments, with non-sterile synthetic wastewater, confirmed the results from the aerobic batch degradation experiments. Both ABS isomers were degraded in long-term continuous experiment by a bioaugmented enrichment culture. The maximum degradation rate in the aerobic bioreactor was 1.6-1.8 g 1(-1) d(-1) for 2-ABS and a somewhat lower value for 4-ABS at hydraulic retention times (HRT) of 2.8-3.3 h. Evidence for extensive mineralization of 2- and 4-ABS was based on oxygen uptake and carbon dioxide production during the batch experiments and the high levels of chemical oxygen demand (COD) removal in the bioreactor. Furthermore, mineralization of the sulfonate group was demonstrated by high recovery of sulfate. The sulfonated aromatic amines did not show any toxic effects on the aerobic and anaerobic bacterial populations tested. The poor biodegradability of sulfonated aromatic amines indicated under the laboratory conditions of this study suggests that these compounds may not be adequately removed during biological wastewater treatment.

Aerobiosis↗

PubMed2005

Tertiary activated carbon treatment of paper and board industry wastewater.

The feasibility of activated carbon post-treatment of (biologically treated) wastewater from the paper and board industry was investigated, the goal being to remove refractory organic pollutants and produce water that can be re-used in the production process. Because closing water-circuits in the paper and board industry results in higher water temperatures, the effect of the temperature on activated carbon treatment was also investigated. Batch and column adsorption tests showed that activated carbon provides an excellent removal of cationic demand and color related compounds, the two most important representatives of organic compounds that have to be removed. Unexpectedly, higher water temperatures enhanced the performance of activated carbon. However, the treatment costs, mainly determined by transport and regeneration of the carbon, were very high. At long contact times between the wastewater and the carbon the occurrence of biodegradation was observed. Biological regeneration of the carbon may therefore provide a means to reduce the treatment costs, but a practical application requires further research.

Adsorption↗

PubMed2003

Kinetic comparisons of mesophilic and thermophilic aerobic biomass.

Kinetic parameters describing growth and decay of mesophilic (30 degrees C) and thermophilic (55 degrees C) aerobic biomass were determined in continuous and batch experiments by using oxygen uptake rate measurements. Biomass was cultivated on a single soluble substrate (acetate) in a mineral medium. The intrinsic maximum growth rate ( micro (max)) at 55 degrees C was 0.71+/-0.09 h(-1), which is 1.5 times higher than the micro (max) at 30 degrees C (0.48+/-0.11 h(-1)). The biomass decay rates increased from 0.004 h(-1) at 30 degrees C to 0.017 h(-1) at 55 degrees C. Monod constants were very low for both types of biomass: 9+/-2 mg chemical oxygen demand (COD) l(-1)at 30 degrees C and 3+/-2 mg COD l(-1)at 55 degrees C. Theoretical biomass yields were similar at 30 and 55 degrees C: 0.5 g biomass COD (g acetate COD)(-1). The observed biomass yields decreased under both temperature conditions as a function of the cell residence time. Under thermophilic conditions, this effect was more pronounced due to the higher decay rates, resulting in lower biomass production at 55 degrees C compared to 30 degrees C.

Aerobiosis↗

PubMed2003

A new method to study biodegradation kinetics of organic trace pollutants by activated sludge.

A reliable prediction of the behaviour of organic trace compounds in activated sludge plants requires an accurate input of the biodegradation kinetics. Often these kinetics are extrapolated from the results of standardised biodegradation tests. However, these tests generally are not designed to yield kinetic information and do not reflect the conditions in activated sludge plants. To overcome these problems a new test method was developed which is referred to as a 'by-pass' test. The test methodology is explained and examples are given for three compounds: the C(12)-homologue of linear alkylbenzene sulfonate, nitrilotriacetic acid and toluene. More experience with the test is required, particularly with respect to selection of the proper test settings, which are compound related. The test is a suitable tool in a research environment, for example to investigate the effect of plant operational parameters on the biodegradation kinetics.

Biodegradation, Environmental↗