Survey on number and size distribution of treatment wetlands in Austria.

In Austria, 1,840 wastewater treatment plants (WWTPs) with design size >50 population equivalent (PE) serve about 95% of the population. The remaining 5% of the population live in single houses and small settlements that require on site and decentralized wastewater treatment technologies. There is no common database on small WWTPs with design size <50 PE; thus data had to be collected from the Austrian federal states and compiled in a database.

Influence of the gas composition on the efficiency of ammonia stripping of biogas digestate.

Impact of strip gas composition on side stream ammonia stripping, a technology aiming at the reduction of high ammonia levels in anaerobic reactors, was investigated. Evaluation of the effect of oxygen contact during air stripping showed a distinct, though lower than perceived, inhibition of anaerobic microflora. To circumvent, the feasibility and possible constraints of biogas and flue gas as alternatives in side stream stripping were studied.

Environmental sustainability of an energy self-sufficient sewage treatment plant: improvements through DEMON and co-digestion.

It is still not proven that treatment of sewage in a wastewater treatment plant (WWTP) is (in every case) environmentally friendly. To address this matter, we have applied a state-of-the-art life cycle assessment (LCA) to an energy self-sufficient WWTP in Strass (Austria), its supply chain and the valorization of its 'products': produced electricity out of biogas from sludge digestion and the associated stabilized digestate, applied as agricultural fertilizer. Prominent aspects of our study are: a holistic environmental impact assessment, measurement of greenhouse gas emissions (including N2O), and accounting for infrastructure, replacement of conventional fertilizers and toxicity of metals present in the stabilized digestate.

Waste management in mountain refuges - an integrated evaluation.

Mountain refuges are an excellent example of public stand-alone infrastructures equipped with energy and water supply, and wastewater and waste disposal systems suited to operating under unfavourable conditions, often comprising lengthy distances for transportation or scarce resources. An international project was undertaken to evaluate the existing supply and disposal schemes at 100 mountain refuges both individually and in an integrated manner. On the basis of the results obtained guidelines to be applied in the sustainable planning, construction and operation of supply and disposal systems will be published in the near future.

Gaseous nitrogen and carbon emissions from a full-scale deammonification plant.

The aim of this work was to give a quantitative description of the gaseous nitrogen and carbon emissions of a full-scale deammonification plant (DEMON system). Deammonification accounted for the net carbon sequestration of 0.16 g CO2/g NO2-N.

Fate of cancerostatic platinum compounds in biological wastewater treatment of hospital effluents.

The present work focuses on the fate of two cancerostatic platinum compounds (CPC), cisplatin and carboplatin, as well as of two inorganic platinum compounds, [PtCl(4)](2-) and [PtCl(6)](2-) in biological wastewater treatment. Laboratory experiments modelling adsorption of these compounds onto activated sludge showed promising specific adsorption coefficients K(D) and K(OC) and Freundlich adsorption isotherms. However, the adsorption properties of the investigated substances were differing significantly.

Determination of activated sludge biological activity using model corrected CO2 off-gas data.

Carbon dioxide (CO(2)) online off-gas monitoring is useful to detect changes in biological activity for activated sludge systems especially under limited oxygen conditions like under simultaneous nitrification-denitrification (SND) where respirometric measurements are not applicable. So far, the influence of the bicarbonate system on the liquid-gas transfer of CO(2) prevented the wider use of off-gas CO(2) for monitoring purposes in wastewater treatment. The objective of the paper is to demonstrate a practical method to correct measured off-gas CO(2) as an indicator of biological activity by taking into account pH shifts (resulting in CO(2) release or retention) and changes in influent alkalinity.

NOx monitoring of a simultaneous nitrifying-denitrifying (SND) activated sludge plant at different oxidation reduction potentials.

Simultaneous nitrification-denitrification (SND) allows biological nitrogen removal in a single reactor without separation of the two processes in time or space but requires adapted control strategies (anoxic/aerobic conditions). In this study, the formation of gaseous nitric oxide (NO(G)) and nitrogen dioxide (NO(2G)) was monitored for SND in relation to the oxidation-reduction potential (ORP) and nitrogen removal in a lab batch reactor and a pilot membrane bio-reactor (MBR). In addition hospital wastewater (COD/N(tot)>6:1) was treated on site for 1 year.

Presence of cancerostatic platinum compounds in hospital wastewater and possible elimination by adsorption to activated sludge.

Platinum originating from the excreted cancerostatic platinum compounds (CPC) cisplatin, carboplatin and oxaliplatin was monitored over a period of 28 days in the wastewater of the oncologic ward of the Vienna University Hospital. Concentration levels ranging from 4.7 to 145 microg L(-1) were measured by inductively coupled plasma mass spectrometry (ICP-MS).