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Wastewater contains a diverse array of organic and inorganic compounds and its complex composition strongly depends on the location and the connected dischargers. However, municipal wastewater as a carrier of feces and urine generally contains considerable amounts of the main nutrients nitrogen and phosphorus. The latter is in the focus of the discussions about the recovery potential of wastewater due to the relatively high mass flows of phosphorus in wastewater and the finite nature and decreasing quality of phosphate rock reserves. But due to the presence of the whole periodic table of elements, wastewater might contain further valuable components of interest for recovery including those defined as critical raw materials by the European Commission. Phosphorus and most of the other critical raw materials are fixed in the sewage sludge and after incineration in the sewage sludge ash (SSA). This is accompanied by high concentration factors from wastewater via sludge to ash. However, the mass fractions of the majority of elements in sewage sludge are comparable to those of the earth crust, indicating no relative enrichment. Nevertheless, enrichment factors of 100 or higher are given for phosphorus, copper, zinc, cadmium, silver, tin, lead and the platinum group elements indicating an anthropogenic input. An economic value of sewage sludge was estimated to $460,-/t calculated on the basis of the respective market prices for high purity elements – a theoretical value. A German survey of sewage sludge ashes showed that the mass fractions and the mass flows of most of the elements present in SSA are probably too low for an economic recovery. In most cases the mass flows are rather small compared to the imports and the chemical forms are not suitable for recovery. An exception is phosphorus that is present in high mass fractions up to 13% and that bears a high substitution potential. If the application of P-recovery technologies lead to a further concentration of valuable elements e.g. as by-products in side streams of the process, it would probably make also the recovery of other elements of economic interest.
The scope of our study was to prepare Fe-based highly active catalysts for water treatment processes. The reactive nanomaterials were
synthesized by chemical precipitation; the post-synthesis coating of the as obtained nanostructures was achieved by capping the magnetic cores with a
polymeric surfactant, polyethylene glycol (PEG). The resulted Fe3O4/PEG nanoparticles were further used to immobilize two types of reactive materials on
their surface, either ferrous oxalate (FO) or ferric citrate (FC), yielding the final products – two green Fenton-like heterogeneous nanocatalysts. The
sensitized catalysts were characterized by several microstructure characterization techniques such as X-ray diffraction (XRD), vibrating sample
magnetometry, BET, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). All experiments were performed on a
laboratory scale set-up. Important variables such as effect of hydrogen peroxide concentration, UV light, the amount of catalyst and contact time for the
catalytic wet peroxide oxidation (CWHPO) of BPA were examined. The results indicate that the oxidation rate increased under UV light in the presence of
low-concentration H2O2.
Due to the demand of monitoring the water quality regarding emerging pollutants, such as drug residues, selective, high-throughput and multi-target analytical methods must be established. On the one hand, the influence of sewage on natural surface waters must be routinely monitored. On the other hand, estimation of removal efficiencies of pollutants, such as drug residues, is in the focus of industrial and public wastewater treatment. Immunoassays, such as ELISA, offer the possibility to be highly sensitive and selective due to the high target affine and specific recognition of antibodies to target molecules. Batch-wise processing in microtiter plates allow the necessary high-throughput, but only a single analyte can be determined within one measurement.
To overcome these disadvantages, we developed a four-plex micro-bead based flow cytometric assay, which is adaptable for the microtiter plate format. The modular and self-prepared bead support consists of polystyrene-core-silica-shell particles. While the polystyrene core is used for encoding, by introducing different amounts of fluorescent dyes, the silica-shell creates a solid-support for the immunoassay: The target analytes, three drugs, carbamazepine, diclofenac and caffeine and the f ecal marker isolithocholic acid are covalently coupled to amino-groups on the surface via NHS-chemistry. A competitive immunoassay is subsequently conducted in a simple mix-and-read procedure. Finally, we could use SAFIA to assess the influent of treated and untreated waste water on the Douro river estuary in Portugal. The results of the analysis are comparable to ELISA. However, measurements could be carried out in 25% the time of analysis.
Pharmacologically active compounds are omnipresent in contemporary daily life, in our food and in our environment. The fast and easy quantification of those substances is becoming a subject of global importance. The fluorescence polarization immunoassay (FPIA) is a homogeneous mix-and-read format and a suitable tool for this purpose that offers a high sample throughput. Yet, the applicability to complex matrices can be limited by possible interaction of matrix compounds with antibodies or tracer.
Caffeine is one of the most frequently consumed pharmacologically active compounds and is present in a large variety of consumer products, including beverages and cosmetics. Adverse health effects of high caffeine concentrations especially for pregnant women are under discussion. Therefore, and due to legal regulations, caffeine should be monitored. Automated FPIA measurements enabled the precise and accurate quantification of caffeine in beverages and cosmetics within 2 min. Samples could be highly diluted before analysis due to high assay sensitivity in the low μg/L range. Therefore, no matrix effects were observed.
The antiepileptic drug carbamazepine (CBZ) is discussed as a marker for the elimination efficiency of wastewater treatment plants and the dispersion of their respective effluents in surface water. The development of a FPIA for CBZ included the synthesis and evaluation of different tracers. Using the optimum tracer CBZ-triglycine-5-(aminoacetamido) fluorescein, CBZ concentrations in surface waters could be measured on different platforms: one sample within 4 min in tubes or 24 samples within 20 min on microtiter plates (MTPs). For this study, a commercially available antibody was used, which led to overestimations with recovery rates up to 140% due to high cross-reactivities towards CBZ metabolites and other pharmaceuticals.
For more accurate CBZ determination, a new monoclonal antibody was produced. In this attempt, methods for improving the monitoring during the production process were successfully applied, including feces screening and cell culture supernatant screening with FPIA. The new monoclonal antibody is highly specific for CBZ and showed mostly negligible cross-reactivities towards environmentally relevant compounds. Measurements at non-equilibrium state improved the sensitivity and selectivity of the developed FPIA due to slow binding kinetics of the new antibody. Additionally, this measure enables for CBZ determination over a measurement range of almost three orders of magnitude. The comprehensively characterized antibody was successfully applied for the development of sensitive homogeneous and heterogeneous immunoassays.
The new antibody made the development of an on-site measurement system for the determination of CBZ in wastewater possible. After comprehensive optimization, this automated FPIA platform allows the precise quantification of CBZ in wastewater samples only pre-treated by filtration within 16 min. Recovery rates of 61 to 104% were observed. Measurements in the low μg/L range are possible without the application of tedious sample preparation techniques.
Different FPIA platforms including MTPs, cuvettes and tubes were successfully applied. For the choice of the right format, the application field should be considered, e.g. desired sample throughput, usage for optimization or characterization of antibodies or if a set-up for routine measurements is sought for. For high sample throughput and optimization, FPIA performance on MTPs is advantageous. The best results for the application to real samples were obtained using kinetic FP measurements in cuvettes.
Bisphenol A (BPA) is widely used in many Polymers. Many outdoor applications are made from BPA-based materials which are exposed to a variety of environmental impacts, like temperature, solar radiation, rain, and others. This could lead to damaging and aging of the material which might cause leaching or migration of pollutants into the environment. To understand the fate and behavior different transformation products of selected Bisphenols will be generated and analyzed.
Bisphenol A (BPA) is widely used in Polycarbonate (PC), Polyacrylic resins (PAR), Polysulfones (PSU), Epoxy resins (ER), and Polyetherimides (PEI). It is also used in recycled Polyvinyl chloride (PVC) [1–3]. These BPA-containing materials have a wide area of application, especially outside. All outdoor applications are exposed to a variety of environmental impacts, like temperature, solar radiation (physical influences), chemical influences (rain or ozone), biological influences (microorganisms), and mechanical influences (hail, sand). These impacts are damaging and aging the material which can be followed by leaching or migration of pollutants like Bisphenol A into the environment. Understanding the fate and behavior of the released pollutants is very important. Therefore, different transformation products of selected Bisphenols will be generated and analyzed.
Bisphenol A (BPA) is used in Polycarbonate, Polyacrylic resins, Polysulfones, Epoxy resins, and Polyetherimides. It is also used in recycled Polyvinyl chloride [1–3]. BPA has been classified as a substance of very high concern (SVHC) under REACH [4] due to its endocrine disrupting properties. The German competent authorities want to reduce the content of BPA in the environment. Possible substitutes for BPA are Bisphenol B (BPB), Bisphenol E (BPE),
Bisphenol F (BPF), or Bisphenol S (BPS), as they are similar in structure.
BPA-based materials have a wide area of application especially outside. These outdoor applications are exposed to different external influences, including physical, biological, mechanical and chemical influences. This results in damage and aging of the material with leaching or migration into the environment. There, the substance is transformed by various transformation processes. The emerging metabolites and transformation products (TPs) can have different properties than the parent substance. Understanding the fate and behavior of the emerging pollutants is very important.
Therefore, different transformation products of selected bisphenols will be generated and analyzed:
To investigate the fate of different bisphenols in water treatment plants technical transformation products [5] will be generated by chlorination, ozonization, the Fenton reaction, and UV-radiation.
For the investigation of the fate of Bisphenols in surface water global radiation will be simulated with UVA-lamps
Simulation of phase-I-metabolism with an electrochemical cell coupled to mass spectrometry (EC-MS).
Two types of surface modified magnetite (Fe3O4) nanoparticles, coated with either tannic acid (TA) or dissolved natural organic matter (NOM), were evaluated as magnetic heterogeneous catalysts. Simple and efficient procedures for the synthesis of the magnetic catalysts were employed, their properties being fully assessed by various characterization techniques. The catalytic activity in heterogeneous oxidation of aqueous solutions containing Bisphenol A (BPA) over the catalysts was comparatively studied. The optimum experimental parameters were: 1g/L of catalysts, 10 mM H2O2, under UV irradiation. The highest mineralization rates were observed for Fe3O4-TA catalyst. More than 80% of BPA were removed after 30 minutes of reaction time under the specified experimental conditions. The results showed that the obtained catalysts are suitable candidates for the removal of pollutants in wastewaters by means of heterogeneous reaction
Pharmacologically active compounds are often detected in wastewater and surface waters. The nonsteroidal anti-inflammatory drug diclofenac was included in the watch list of substances in the EU that requires their environmental monitoring in the member states. DCF may harmfully influence the ecosystem and the natural organization already at concentrations of ≤1 μg/l. The fast and easy quantification of DCF is becoming a subject of global importance. Fluorescence polarization immunoassay (FPIA) is a homogeneous mix-and-read method, which does not require the immobilization of reagents, they can be performed in one phase, making it possible to analyze wastewater without any complicated pre-treatment, performed within 20–30 min.