Holger Gulyas

Ryegrass uptake of carbamazepine and ibuprofen applied by urine fertilization.

Human urine is a potential alternative fertilizer for agriculture. However, its usage is associated with a risk of spreading pharmaceutical residues to fields. The individual and combined behavior of carbamazepine and ibuprofen was investigated by GC/MS analysis in a greenhouse experiment using ryegrass fertilized with pharmaceutical-spiked urine. Only carbamazepine could be detected in soil, roots, and aerial plant parts. Fifty-three per cent of carbamazepine originally present in the urine was recovered in soil samples taken after three months. Additionally, 34% of carbamazepine was found in aerial plant parts and 0.3% in roots. Model calculations showed that neither roots nor Casparian strip posed a considerable barrier to uptake. Carbamazepine transport was clearly driven by transpiration. Ibuprofen was not detected in the soil or in any plant parts after three months. This was assumed to be due to biodegradation of ibuprofen. Carbamazepine and ibuprofen, singly or in combination, did not adversely affect the growth of ryegrass.

Comparison of analytical and theoretical pharmaceutical concentrations in human urine in Germany

Urine is considered as a valuable plant fertiliser due to its high nutrient content. However, urine also contains pharmaceuticals. Currently, little is known regarding expected pharmaceutical concentrations in urine and the resulting risks. Through series of analyses in Hamburg and Berlin and results from the development of a concentration prediction model this knowledge gap was intended to be filled. To which extent the theoretical calculations can substitute analyses of pharmaceuticals was also tested. Results showed that the model fits well for bezafibrate, carbamazepine, diclofenac, ibuprofen, phenazone, and pentoxifylline. In Hamburg an R(2) value of 0.98 and in Berlin of 0.90 was achieved for correlations between predicted and analysed concentrations. Additionally, it was shown that a sufficient number of people discharging their urine to the respective collection system are important to allow for reasonable predictions via calculation. Also, comparisons of predicted pharmaceutical concentrations to those determined in other projects showed good correlations. Overall, it can be concluded that in any case the calculated concentrations exceed the measured ones and are therefore conservative. This overestimation can be explained by several factors discussed in this article.

A comparison of human pharmaceutical concentrations in raw municipal wastewater and yellowwater

Currently, many articles report on pharmaceutical residues detected in various compartments of the environment. A major pathway into the aquatic environment is municipal wastewater. This article discusses the relevance of yellowwater (urine) as pharmaceutical source within this wastewater stream. Literature data about concentrations of 28 pharmaceutical residues detected in raw wastewater are compared to their theoretically calculated concentrations in urine. The study shows that these pharmaceuticals and their metabolites are excreted predominantly via urine although some substances show reasonable excretion via faeces. It is demonstrated that the influence of pharmacokinetic activities is one important issue affecting the presence of pharmaceuticals in the aquatic environment. Nevertheless, only a weak correlation between concentrations of pharmaceuticals calculated in yellowwater and analysed in raw wastewater was observed. This is due to environmental effects taking place between the excretion of urine and the entrance of sewerage into the wastewater treatment plant. The data show that urine separation and separate handling/treatment of this wastewater stream represents a promising approach to protect the aquatic environment safely from human pharmaceuticals.

Occurrence of Cryptosporidium in a Wastewater Treatment Plant in North Germany

Cryptosporidium parvum is one of the most common human parasitic protozoa and is responsible for many waterborne outbreaks in several industrialized countries. The oocyst, which is the infective form, is known to be highly resistant to wastewater treatment procedures and represents a potential hazard to human populations through contaminated raw or treated wastewater. In this investigation, the occurrence of Cryptosporidium in wastewater samples was monitored and removal efficiency was assessed. Treated (effluent) and untreated (influent) wastewater samples were collected seasonally over a period of 2 years. Oocysts were repeatedly detected in influent and effluent samples collected from the treatment plant during all sampling seasons, with a mean concentration of 782 oocysts/L. The seasonal distribution showed that oocysts are predominant during autumn and winter. Molecular analyses via the small (18S) subunit of rRNA amplification and subsequent sequencing with an objective of characterizing the oocysts revealed that Cryptosporidium parvum was the dominant Cryptosporidium parasite present in wastewater.

Degradation of triethylene glycol dimethyl ether by ozonation combined with UV irradiation or hydrogen peroxide addition

Ozonation of pure aqueous solutions of the polar aliphatic refractory triethylene glycol dimethyl ether (TEGDME) which is a typical representative of organic solutes of oil reclaiming wastewaters does not lead to effective mineralization unless high ozone doses are applied. Small doses of UV irradiation do not markedly increase TEGDME mineralization by ozonation, but transformation to more oxidized products (mainly carboxylic acids containing methoxy and/or ethoxy groups) which are biodegradable to a higher degree than TEGDME. Addition of high concentrations of hydrogen peroxide during ozonation results in efficient increase of TEGDME mineralization, however. The presence of humic acids - which is a consequence of biological treatment of wastewaters containing biodegradable organic constituents - has a beneficial effect on transformation of TEGDME during ozonation or ozone/UV treatment because hydrogen peroxide is formed during ozonation of humic acid C-C double bonds.

Combining activated carbon adsorption with heterogeneous photocatalytic oxidation: Lack of synergy for biologically treated greywater and tetraethylene glycol dimethyl ether

The aim of the study was to evaluate whether the addition of activated carbon in the photocatalytic oxidation of biologically pretreated greywater and of a polar aliphatic compound gives synergy, as previously demonstrated with phenol. Photocatalytic oxidation kinetics were recorded with fivefold concentrated biologically pretreated greywater and with aqueous tetraethylene glycol dimethyl ether solutions using a UV lamp and the photocatalyst TiO2 P25 in the presence and the absence of powdered activated carbon. The synergy factor, SF, was quantified as the ratio of photocatalytic oxidation rate constant in the presence of powdered activated carbon to the rate constant without activated carbon. No synergy was observed for the greywater concentrate (SF≈ 1). For the aliphatic compound, tetraethylene glycol dimethyl ether, addition of activated carbon actually had an inhibiting effect on photocatalysis (SF<1), while synergy was confirmed in reference experiments using aqueous phenol solutions. The absence of synergy for the greywater concentrate can be explained by low adsorbability of its organic constituents by activated carbon. Inhibition of the photocatalytic oxidation of tetraethylene glycol dimethyl ether by addition of powdered activated carbon was attributed to shading of the photocatalyst by the activated carbon particles. It was assumed that synergy in the hybrid process was limited to aromatic organics. Regardless of the lack of synergy in the case of biologically pretreated greywater, the addition of powdered activated carbon is advantageous since, due to additional adsorptive removal of organics, photocatalytic oxidation resulted in a 60% lower organic concentration when activated carbon was present after the same UV irradiation time.

Solar Heterogeneous Photocatalytic Oxidation for Water and Wastewater Treatment: Problems and Challenges

Solar operation of heterogeneous photocatalytic oxidation reactors is looked at as a sustainable process for water and wastewater treatment, because it does not consume electric power and chemicals. However, there are still problems for technical-scale application. The problems addressed in this article are large area demand, water evaporation from open reactors and lack of simple photocatalyst recovery. An optimum solar reactor type is the parabolic compound collector reactor with borosilicate glass tubes. Challenges for further research are improvement in mass transfer as well as identification of novel photocatalysts which make use also of visible light, are efficient and stable, and are easy to be produced in an economically feasible way. Also the combination of photocatalysts with adsorbents is promising. Although membrane filtration processes have been successfully combined with solar photocatalytic oxidation and represent a safe barrier against spreading photocatalyst nanoparticles into the aquatic environment, more simple and less energy-consuming methods for photocatalyst recovery would be desirable.

Organic micropollutants in raw and treated greywater: a preliminary investigation

Effluent and influent of a constructed wetland treating separately collected greywater were subjected to liquid/liquid extraction with dichloromethane as well as to solid phase extraction. Extracts were analysed by gas chromatography/mass spectrometry. More than 80 organics were tentatively identified or roughly characterised in the raw greywater by their mass spectra. A lower number (26) of organic compounds was tentatively identified in the constructed wetlands effluent. Major compounds found in at least one extract of the effluent were an alkane, a squalene isomer, hexadecanoic acid, two not exactly identified phthalates, tris-chloropropyl phosphate, an acephylline derivative and an unidentified nitrogenous heterocycle. The persistent flame retardant tris-chloropropyl phosphate and a couple of phthalates found in the biologically treated greywater are of concern when biologically treated greywater will be reused for high quality demand. Most of the trace organics found in the greywater samples were related to household chemicals, personal care products and foodstuffs.

Measuring nitrate concentration in wastewaters with high chloride content

ABSTRACT The presence of chloride ions in wastewaters in concentrations above 50 mg/L poses interference in several methods used for the measurement of nitrate-nitrogen. The aim of this study was to characterise the reliability and costs of some commonly available methods for the analysis of nitrate concentration in landfill leachate which contains high chloride levels. To investigate the effect of chloride interference, several widely used methods [ion chromatography (IC), continuous flow analysis (CFA), the German standard method (DIN), cuvette test (CUV), standard addition method (SAM) and reflectometric test (REF)] were used to measure the nitrate concentration in synthetic solutions containing varying concentrations of chloride and nitrate-nitrogen. Nitrate recoveries of the various methods were found to decrease in the following rank order: CUV (>95%) > IC (>90%) > CFA (89%) > DIN (88%) > REF (70%) > SAM (<80%). In the second part of the study, the same methods were used to measure nitrate concentrations in samples of biologically nitrified landfill leachate with and without chloride elimination. For leachate samples without chloride elimination, CUV results were well correlated (linear regression) with IC results (slope = 1.02/R2 = 0.99) but to lesser extents with results obtained by CFA (0.91/0.86), DIN (0.89/0.97) and REF (0.86/0.77), and not correlated with SAM (0.74/–1.3). The incurred measurement costs per sample (in Euros) for the methods were as follows: CFA (<0.1) < DIN (0.6) < REF (0.7) < SAM (3) < CUV (3.8) < IC (15). Cuvette tests are recommended as the method of choice due to their accuracy and lower cost than IC.

TiO2 Photocatalyst Nanoparticle Separation: Flocculation in Different Matrices and Use of Powdered Activated Carbon as a Precoat in Low-Cost Fabric Filtration

Separation of photocatalyst nanoparticles is a problem impeding widespread application of photocatalytic oxidation. As sedimentation of photocatalyst particles is facilitated by their flocculation, the influence of common constituents of biologically pretreated wastewaters (NaCl, NaHCO3, and their combination with humic acid sodium salt) on flocculation was tested by the pipet method. Results showed that the impact of these substances on TiO2 nanoparticle flocculation is rather complex and strongly affected by pH. When humic acid was present, TiO2 particles did not show efficient flocculation in the neutral and slightly basic pH range. As an alternative to photocatalyst separation by sedimentation, precoat vacuum filtration with powdered activated carbon (PAC) over low-cost spunbond polypropylene fabrics was tested in the presence of two PAC types in aqueous NaCl and NaHCO3 solutions as well as in biologically treated greywater and in secondary municipal effluent. PAC concentrations of  g/L were required in order to achieve a retention of nearly 95% of the TiO2 nanoparticles on the fabric filter when TiO2 concentration was 1 g/L. Composition of the aqueous matrix and PAC type had a slight impact on precoat filtration. PAC precoat filtration represents a potential pretreatment for photocatalyst removal by micro- or ultrafiltration.