bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrated biological treatment of recalcitrant effluents from pulp mills
Authors: Ortega-Clemente A. , Estrada-Vázquez C. , Esparza-Garcia F. , Caffarel-Mendez S. , Rinderknecht-Seijas N. , Poggi-Varaldo H.M.
Published: May 2018

This work aimed at determining the degree of depuration of a recalcitrant effluent (weak black liquor, WBL) achieved in a series treatment consisting of a first stage methanogenic fluidised bed reactor followed by a second stage aerobic, upflow reactor packed with “biocubes” of Trametes versicolor immobilised onto small cubes of holm oak wood. The mesophilic, lab scale methanogenic fluidised bed reactor contained a microbial consortium immobilised onto granular activated carbon 500 mm average size. The process removed decreasing amounts of organic matter at decreasing hydraulic retention times (HRT), eventually reaching an average of 50% at 0.5 day HRT. Colour and ligninoid removals also decreased with decreasing HRT. Although the methanogenic fluidised bed reactor provided an effective treatment for the degradable organic matter, important concentrations of recalcitrant organic matter and colour still remained in the anaerobic effluent. This anaerobic effluent was fed to the aerobic packed bed reactor. Two HRT were tested in this unit, namely 5 and 2.5 days. The reactor averaged an organic matter removal in the range of 32% COD basis, during an experimental run of 95 days. Colour and ligninoid contents were removed in high percentages (69% and 54%, respectively). There was no significant difference in reactor performance at 5- and 2.5-day HRT. There was a positive correlation between pollutant removal efficiencies and Laccase activity in crude extracts of the reactor liquor. No supplemental soluble carbohydrate was required to sustain the fungus activity and the consistent reactor performance. Overall, the two-stage treatment achieved approximately a 78% removal of the original organic matter of the WBL (COD basis) and ca. 75% of colour and ligninoid contents.
Spectroscopic evidence of silica-lignin complexes: implications for treatment of non-wood pulp wastewater
Authors: Nour M.H. , Smith E.H. , Walther J.V.
Published: May 2018

This research examined the hypothesis that lignin compounds form aqueous complexes with silica increasing its solubility, thereby inhibiting its precipitation. An experimental program using four lignin model compounds was conducted to test the hypothesis. Laser Raman spectroscopy (LRS) was used to characterize, qualitatively, the interaction between lignin and aqueous silica, and to identify the possibility of silica-lignin complexation. Solubility studies were then performed by analyzing the solubility of silica in presence and absence of lignin within the relevant pH range to confirm the results of LRS, and to obtain a quantitative assessment of the relative solubility. The findings have established the formation of silica-ferulic, silica-vanillic, and silica-4-methoxycinnamic acid complexes, but no evidence was detected for the formation of silica-veratryl alcohol complex. In fact, the black liquor undoubtedly contains much more complex lignin materials than the simple model compounds used in this work. The more complex lignin compounds are likely to have an even greater tendency to form silica complexes, thus contributing to the initial hypothesis. This finding provides a fundamental understanding as to why previous efforts to precipitate silica by lowering the pH from 10-11 (for black liquor) to less than 9 did not achieve satisfactory silica separation, and why alternative strategies need to be investigated.
How Dutch drinking water production is affected by the use of herbicides on pavements
Authors: Bannink A.D.
Published: May 2018

About forty per cent of drinking water in The Netherlands is produced from surface water. Dutch water companies, that have to rely on this source, are dealing with major water quality problems due to the use of herbicides on pavements. Voluntary measures and bans have had only limited effect on the reduction of emissions of herbicides that runoff from pavements into surface water in The Netherlands. The effects on the production of drinking water from surface water should play a role in the authorisation of pesticides. Stricter regulations, including mandatory emission reduction measures and certification, are necessary. The enforcement of existing Dutch surface water pollution laws should solve part of the problem. Due to the international nature of most of the surface water used for drinking water supply, it is necessary that other countries take measures as well. European legislation brings a solution closer if implemented well and seriously enforced. The threat of strict legislation keeps pressure on the transition towards decreasing the dependence on chemicals for weed control on pavements.
How to assess chemical oxidation efficiency
Authors: Bertanza G. , Pedrazzani R.
Published: May 2018

In this work, a real wastewater (deriving from the chemical-pharmaceutical field) was treated by means of H2O2/UV process under different conditions in a pilot-scale plant. Several methods were used in order to assess the oxidation efficiency and to understand the main reaction features. It was shown that non-conventional COD measurement (with a 75°C digestion of the sample) is helpful for understanding reaction mechanisms, when integrated with TOC and COD analyses and GC-MS determinations. For the biodegradability study, beside BOD (5 and 20 days) measurements, OUR and AUR tests provide additional information especially when wastewater is tested by taking the activated sludge from the treatment plant which should really be fed with it. Finally, dehydrogenase activity measurements can show the presence of complex organic matter, which may be degraded only by an acclimated biomass.
Water Environment Research Foundation (WERF) anaerobic digestion and related processes, odour and health effects study
Authors: Witherspoon J.R. , Adams G. , Cain W. , Cometto-Muniz E. , Forbes B. , Hentz L. , Novack J.T. , Higgins M. , Murthy S. , McEwen D. , Ong H.T. , Daigger G.T.
Published: May 2018

Biosolids odour emissions can affect the ability of wastewater utilities to implement beneficial biosolids processing and reuse programs. Communities often become more sensitised and vocal about biosolids issues, once they experience odours emanating from a nearby site. Odour impacts from biosolids, including potential human health effects, have been targeted recently by many national and local newspapers, citizens' groups, and regulatory agencies, who have raised significant concerns, ranging from viable disposal methods/sites to outright bans. Many national and local regulatory agencies in the United States are considering biosolids disposal bans in their communities because of misinformation, poor science, and citizen pressure, but primarily because of odour impact concerns. The wastewater industry has a relatively poor understanding of the operations and treatment parameters that influence biosolids odour emissions. Thus, wastewater treatment plants are often unable to control the odour quality of the biosolids that are delivered into communities. A research study to demonstrate the influence of anaerobic digestion, mechanical dewatering, and storage design and operating parameters on the odour quality of the final product was performed and is the subject of this paper. Established and new sampling and analytical methods were used to measure biosolids odour emissions from 11 test sites in North America. By determining the impacts of these control variables on biosolids odour quality, design and operations of anaerobic digestion systems might be enhanced. This paper also summarises a corollary study performed as part of the WERF research study that addresses the health effects of biosolids odours.
Taking mass transfer limitation into account during ozonation of pollutants reacting fairly quickly
Authors: Benbelkacem H. , Mathé S. , Debellefontaine H.
Published: May 2018

Various situations observed when oxidizing organic compounds via ozone in a semi-batch reactor are illustrated. The resistance to the transfer of ozone from gas to liquid is accounted for using the film model. The mass balances are numerically solved simultaneously within the reactor and within the film to produce time dependent profiles of concentrations, Hatta, enhancement and depletion factors. Firstly, theoretical profiles are exemplified for various kinetic regimes from slow to fast; reaction occurs either in the bulk, in the film or in both. This shows the drastic importance of the shapes of the gas concentration profiles - both at the exit of the reactor and in the liquid phase - in determining the regime. Then, a typical example dealing with fumaric acid ozonation is shown. Firstly, the acid itself oxidizes rapidly producing an intermediate regime: part of the reaction occurs within the film, part within the bulk and the rate constant can be determined. Then, the by-products oxidize more slowly producing a typical regime: reaction occurs within the bulk, the concentration of dissolved ozone is almost 0 and the mass transfer coefficient can be determined. Finally, when all organics have oxidized, the self-decomposition of ozone governs a slow kinetic regime: the concentration of dissolved ozone is close to equilibrium.
The value of an odor-quality-wheel classification scheme for wastewater treatment plants
Authors: Suffet I.H. (Mel) , Burlingame G.A. , Rosenfeld P.E. , Bruchet A.
Published: May 2018

Each odorant possesses a unique odor signature (i.e. odor character or quality, odor threshold and chemical concentration). This paper develops an initial understanding of how the volatile odorous chemicals and their relative concentrations produced are related to the total odor quality from the process by their odor threshold concentrations and odor signatures.
Degradation of recalcitrant compounds by catechol-driven Fenton reaction
Authors: Rodriguez J. , Contreras D. , Oviedo C. , Freer J. , Baeza J.
Published: May 2018

Dihydroxybenzenes are able to reduce Fe(III) and promote the Fenton reaction in the presence of H2O2. The catechol/Fe(III)/H2O2 system has been successfully used to degrade different compounds, being more efficient than the Fe(II)-Fenton reaction. In this paper the possibilities for using the catechol-driven Fenton reaction to degrade recalcitrant compounds such as the Fe(III)-EDTA complex and veratryl alcohol are reviewed.
The catalytic and photocatalytic oxidation of organic substances using heterogeneous Fenton-type catalysts
Authors: Kuznetsova E.V. , Savinov E.N. , Vostrikova L.A. , Echevskii G.V.
Published: May 2018

This paper deals with catalytic and photocatalytic oxidation of organic substances using H2O2 over heterogeneous Fenton-type catalysts. In the study a series of Fe-containing catalysts was experienced. A zeolite named as FeZSM-5 was selected as the most active heterogeneous Fenton-type catalyst. The FeZSM-5 reported was prepared by hydrothermal crystallization in the presence of iron salt. In contrast to the homogeneous Fenton system the catalyst prepared had minimal, if any, leaching of iron ions, was stable during 30 catalytic runs and didnÕt lose its activity in the presence of complexing agents, e.g. P2O74-. The catalyst was active in oxidation of organic substances at pH from 1.5 to 8, maximum activity was observed at pH = 3. The FeZSM-5 effectively oxidized a simulant of the warfare agent, diethylnitrophenil phosphate, which is hardly detoxified by other methods. It appeared that the rate of oxidation of formic acid, ethanol and benzene over FeZSM-5 increased under the action of visible light (λ>436 nm), quantum efficiency being 0.06-0.14.
Photooxidation of 2,4-dichlorophenoxyacetic acid by ferrous oxalate-mediated system
Authors: Kwan C.Y. , Chu W.
Published: May 2018

The photodegradation of a herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) by ferrous oxalate/UV/H2O2 was studied. Ferrous oxalate, the more photoactive and reactive species, was found to react faster with hydrogen peroxide for hydroxyl radical production than ferrous ions under UV irradiation. About 2.9 times greater rate enhancement was found with the addition of 0.3 mM oxalate than that of a solution containing 0.1 mM Fe2+ and 1 mM H2O2 in the presence of UV light at 253.7 nm. The kinetics dependence of hydrogen peroxide concentration and initial solution pH were also investigated. A threefold increase in peroxide concentration could accelerate the removal of 2,4-D and nearly complete the reaction in 30 min of illumination. The initial decay rate of 2,4-D treated by ferrous oxalate/UV/H2O2 accelerated from 0.0029 to 0.0034 s-1 and the overall removal of the starting material increased from 78% to 99.9%. The 2,4-D transformation at lower initial pH had higher reaction rates than that at higher pH and different reaction mechanisms were identified. The efficiency of the herbicide decomposition was retarded 2.6 times and 9.6 times as initial pH increased from 2.8 to 5.1 and 9.0, respectively.
Photocatalytic water treatment: fundamental knowledge required for its practical application
Authors: Hufschmidt D. , Liu L. , Selzer V. , Bahnemann D.
Published: May 2018

This review attempts to present a state-of-the art overview of the underlying principles of photocatalysis that should not be neglected when designing pilot-scale facilities. In particular, the roles and properties of the primary charge carriers generated upon bandgap illumination within a photocatalyst particle, i.e. valence band hole and conduction band electron, are discussed. The chemical nature of the primary oxidant is critically assessed.
Electrochemical oxidation of drug residues in water by the example of tetracycline, gentamicine and aspirin®
Authors: Weichgrebe D. , Danilova E. , Rosenwinkel K.-H. , Vedenjapin A.A. , Baturova M.
Published: May 2018

Electro-chemical oxidation as a method to destroy drug residues like aspirin®, tetracycline or gentamicine in water was investigated with C-anodes (modified by manganese oxides) and Pt anodes. The mechanism of aspirin® and tetracycline oxidation and the influence of the biocide effect was observed using GC-MS and three different microbiological tests. In general, the biological availability increases with progressive oxidation of the antibiotics.
Electrochemical advanced oxidation process using DiaChem®electrodes
Authors: Tröster I. , Schäfer L. , Fryda M. , Matthée T.
Published: May 2018

The electrochemical advanced oxidation process (EAOP) using boron doped diamond (DiaChem®, registered trademark of Condias GmbH) has been studied for wastewater treatment and drinking water disinfection. DiaChem® electrodes consist of preferentially metallic base materials coated with a conductive polycrystalline diamond film by hot-filament chemical vapour deposition. They exhibit high overpotential for water electrolysis as well as high chemical inertness and extended lifetime. In particular the high overpotential for water decomposition opens the widest known electrochemical window, allowing the energy efficient production of hydroxyl radicals directly from aqueous solutions. The hydroxyl radicals on the other hand are effectively used for the oxidation of pollutants. The EAOP using DiaChem® electrodes thus facilitates the direct and, if necessary, complete decomposition of even hazardous or persistent pollutants in different wastewaters. Current efficiencies of more than 90%, also without the use of additives for hydroxyl radical generation, have been demonstrated. Additionally, for drinking water preparation diamond electrodes facilitate disinfection with and without the support of chlorine.
Odour and ammonia removal from pig house exhaust air using a biotrickling filter
Authors: Melse R.W. , Mol G.
Published: May 2018

Odour from agricultural activities, such as the spreading of manure and the housing of animals, is increasingly being considered a nuisance in densely populated countries like the Netherlands. The objective of this research was to study the odour removal from pig house exhaust air by a biotrickling filter that had been implemented for ammonia abatement. At a regular pig production farm, the performance of a running full-scale biotrickling filter was studied for 72 days. Ammonia and odour removal efficiency were on average 79% and 49% respectively. Ammonia removal appeared to be based on an unintended accumulation of ammonium and nitrite in the system, instead of on production and discharge of nitrate. The odour removal efficiency showed a large variation that, for a major part, about 80%, could be attributed to actual changes in the performance of the biotrickling filter. These changes were probably caused by variations in the composition of the air that were not completely reflected by the olfactometrically measured odour concentration, as the many different components that make up the odour each have different removal characteristics. It seemed that the biotrickling filter was operated below its maximum absolute odour removal capacity [OUE/(m3 filter)/s], which means that the absolute odour removal will probably rise at increasing load. It was, however, not possible to distinguish between the influence of either the odour load or the odour concentration on the odour removal, because of a positive correlation between the odour concentration and the air flow. To increase the odour removal efficiency (%), the design of the filter probably needs to be optimised for both well and poorly water-soluble odour components.
Efficiency of nanofiltration for the elimination of steroids from water
Authors: Weber S. , Gallenkemper M. , Melin T. , Dott W. , Hollender J.
Published: May 2018

Steroid hormones such as the synthetic 17-α-ethinylestradiol often persist in the sewage treatment process and metabolites of the natural steroids like estrone from estradiol accumulate resulting in relevant amounts in the aquatic environment. Since biological removal of steroids in the sewage treatment plant is not successfully complete, physical processes such as membrane filtration may become more important. We investigated the elimination of natural and synthetic steroids by nanofiltration using a laboratory membrane reactor. Chemical analysis of 17-β-estradiol, estrone, estriol, 17-α-ethinylestradiol, mestranol, diethylstilbestrol, progesterone and β-sitosterine was performed after solid phase extraction by GC-MS with standard addition. The elimination rate depended on the nanofiltration membrane material. LFC1 membrane consisting of polyamide removed the steroids over 99% whereas PES10 membrane consisting of hydrolysed polyethersulfone was less efficient, obviously caused by different pore sizes and permeability of the membrane structure.
Removal of hormones and pharmaceuticals in the Advanced Water Recycling Demonstration Plant in Queensland, Australia
Authors: Khan S.J. , Wintgens T. , Sherman P. , Zaricky J. , Schäfer A.I.
Published: May 2018

An advanced water recycling demonstration plant was employed to investigate the effectiveness of a number of treatment technologies in the removal of some residuals of commonly prescribed pharmaceuticals as well as natural and synthetic hormones found in sewage. Analysis of targeted compounds was carried out by solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS). Initial tests were undertaken to determine the background concentrations of the analytes during various stages of treatment. Subsequent tests, undertaken by spiking with standard solutions of the target compounds provided further information on the removal efficiencies of some selected treatment modules. The results of the study indicate that while ozonation, microfiltration and nanofiltration were partially effective, treatment by reverse osmosis was the most universally successful in the removal of the target residuals. While significantly more data is required for a full evaluation, this initial investigation suggests that reverse osmosis may be an effective means of removing a wider range of pharmaceutically active residuals and hormones from treated sewage.
Effects of advanced oxidation processes (AOPs) on the toxicity of a mixture of pharmaceuticals
Authors: Andreozzi R. , Campanella L. , Fraysse B. , Garric J. , Gonnella A. , Lo Giudice R. , Marotta R. , Pinto G. , Pollio A.
Published: May 2018

The possibility of applying main AOP techniques, namely ozonation, H2O2/UV photolysis and TiO2 photocatalysis to provide a significant reduction of toxicity of pharmaceutical mixtures has been evaluated. For the preparation of the mixture six pharmaceuticals were chosen among those found at highest concentrations in Sewage Treatment Plant effluents, namely carbamazepine, clofibric acid, diclofenac, sulfamethoxazole, ofloxacin and propranolol.

The blue-green alga Synechococcus leopoliensis and the rotifer Brachyonus calyciflorus were utilised to assess the toxicity of the mixtures after AOP treatments. All the toxicity tests were performed using chronic standardized bioassays. The best results were obtained with ozonation. With this type of treatment a complete removal of mixture toxicity on S. leopolensis was obtained even after the shortest time of application (1 min). The ozonation treatment leads also to removal of all the pharmaceutical mixture toxicity on B. calyciflorus, by applying the oxidizing agent for at least for 2 minutes.
The case of the nonionic alkylphenol ethoxylates in the Mediterranean Sea region: is there a problem?
Authors: Zoller U. , Plaut I. , Hushan M.
Published: May 2018

The concentration profiles of the potential endocrine disrupting nonionic alkylphenol ethoxylate (APEO) surfactants in Israel's rivers, groundwaters and coastal water of the eastern Mediterranean Sea, were found to be within the range of 12.5-74.6, trace - 20.2 and 4.2-25.0 mg/L respectively. Determination of the APEO's homologic distribution revealed “skewing” towards the more toxic shorter-chain ethoxylates. Egg production of zebrafish, Danio rerio, exposed to these actually found the environmental concentrations range of the APEOs decreased, after 20 days, to 89.6 ± 2.1, 84.7 ± 3.9 and 76.9 ± 2.2% of the baseline levels, compared with control, in concentrations of 10, 25 and 75 μg/L respectively. These results suggest that, (a) there is a potential health problem, particularly in countries in which the “hard”/environmentally persistent APEOs are still in use; and (b) the related health-risk is seasonally-dependent, particularly in semi-arid regions where the fluctuations in the water quantities in surface- and groundwater are substantial.
Derivatisation of 4-nonylphenol and bisphenol A with halogenated anhydrides
Authors: Stehmann A. , Schröder H. Fr.
Published: May 2018

The aim of this work is to synthesize and characterise the halogenated derivatives of the endocrine disrupting compounds (EDCs) 4-nonylphenol (4-NP) and bisphenol A (BPA). Characterisation was performed after gas chromatographic (GC) separation on-line coupled to mass spectrometric (MS) detector and a Fourier Transform Infrared (FTIR) spectroscopic detector. Further structure elucidation was done applying Nuclear Magnetic Resonance spectroscopy (NMR).

Two different approaches for the preparation of derivatives were evaluated. At first trifluoroacetyl derivatives were synthesized by the reaction of trifluoroacetic acid (TFA) anhydride and the EDCs in acetonitrile at a temperature of 50°C for 30 minutes. In a second step the 4-NP was derivatised using trichloroacetic acid anhydride and triethylamine in diethyl ether at 20¡C for 30 minutes.

After synthesis the halogenated NP and BPA derivatives were characterised applying GC/MS, GC/FTIR and NMR. Three indices for a successful derivatisation were observed: EI-GC/MS proved a complete derivatisation presenting a characteristic fragmentation pattern for each derivative. The IR spectra obtained by GC/FTIR after derivatisation and separation confirmed the loss of the phenolic O-H stretching vibration at 3,600 cm-1 while typical absorptions for halogenated compounds now were observed. The NMR-spectra contained the predicted resonance signals.
Determination of musks and other fragrance compounds at ng/L levels using CLSA (closed loop stripping analysis) and GC/MS detection
Authors: Mitjans D. , Ventura F.
Published: May 2018

Closed loop stripping analysis (CLSA), a suitable tool for the determination of volatile and semivolatile compounds at low trace levels (ng/l), has been used to determine and quantify seven selected musks and two fragrances (Acetyl cedrene and Amberonne). The obtained extracts are analyzed by high resolution gas chromatography coupled to mass spectrometry (GC/MS) operating in the SIM mode.

Quality parameters such as limit of detection; matrix effects; precision expressed as repeatability and reproducibility relative standard deviations of the method and an estimation of the uncertainty have been evaluated.

The method has been applied to the analysis of wastewater effluents, surface water and tap water from different places in Europe. All samples contained differents musks at ng/l levels with the polycyclic musks Galaxolide and Tonalide and both fragrances, Amberonne and Acetyl cedrene, being the most abundant. These results suggest the importance of studying and controlling the presence of these ubiquitous environmental compounds in water systems.
The effect of bisphenol A and chlorinated derivatives of bisphenol A on the level of serum vitellogenin in Japanese medaka (Oryzias latipes)
Authors: Tabata A. , Watanabe N. , Yamamoto I. , Ohnishi Y. , Itoh M. , Kamei T. , Magara Y. , Terao Y.
Published: May 2018

2,2-bis (4-hydroxyphenyl) propane or Bisphenol A (BPA), has been reported to behave as an endocrine disrupter below acute toxic levels, and is widely present in the water environment. Although BPA is easily chlorinated, very little is reported on the effect of chlorinated BPA to the aquatic organisms. In this study, the estrogenic activities of BPA and its chlorinated derivatives were evaluated by the induction of vitellogenin (VTG) in the serum of mature male Japanese medaka. In addition, the effect of sodium hypochlorite on the decomposition of BPA was tested. The relative potencies of estrogenic activities of chlorinated BPA descended in the order 3,3′-diClBPA>BPA≥3-ClBPA>3,3′,5-triClBPA, and no estrogenic activity was observed in 3,3′,5,5′-tetraClBPA. Lowest Observed Effect Concentration (LOEC) and No Observed Effect Concentration (NOEC) for both 3-ClBPA and 3,3′-diClBPA were 500 μg/L and 200 μg/L, respectively. LOEC for 3,3′,5-triClBPA was >500 μg/L. When BPA was reacted with sodium hypochlorite (24 hours; residual chlorine at 1 ppm), however, complete decomposition of BPA and its chlorinated derivatives was observed. The decrease in BPA and its chlorinated derivatives paralleled the decrease in estrogenic potency evaluated by the induction of vitellogenin (VTG) in the serum of mature male Japanese medaka.
Contamination of sediments in Varna Lake and Varna Bay
Authors: Shtereva G.P. , Dzhurova B.S. , Nikolova T.S.
Published: May 2018

Varna Bay is one of the hot spots along the Black Sea coastal zone. Its ecological state is strongly influenced by the connection with the Varna Lake. Along the lake coast are located many sources of pollution such as rivers, ports, chemical industry, WWTPs. The shipping is another pressure on the environment. The study was carried out in the western part of the Varna Lake and Varna Bay. The following parameters: heavy metals, polichlorinated biphenyls, chlororganic pesticides, phenols, petroleum hydrocarbons were analysed in sediments. The high content of the last one is indicative for an extremely unfavourable long-year exploitation of the lake as a water route. The metals concentration in lakes sediments shows the influence of anthropogenic inputs. Comparative analysis of the sediments shows higher concentrations of contaminants in Varna Lake. and near the ports. As a consequence of the worsened state of the bottom a very poor benthic community characterizes a part of the investigated area in the lake.
Contribution of brominated organic disinfection by-products to the mutagenicity of drinking water
Authors: Echigo S. , Itoh S. , Natsui T. , Araki T. , Ando R.
Published: May 2018

The activity inducing chromosomal aberrations of the mixture of brominated disinfection by-products (DBPs) was approximately three times higher than that of the chlorinated counterparts for the same hypohalous acid dose. With the combination of chromosomal aberration test and a new analytical technique to differentiate total organic chlorine (TOCl) and total organic bromine (TOBr), it was found that TOBr was correlated to the mutagenicity of chlorinated waters. It was also implied that for a bromide-to-TOC ratio of 0.1 (mg/mg C), brominated DBPs could account for at least 29% of the total toxicity of DBPs formed during chlorination. On the other hand, bromate ion, a major ozonation DBP, was not a major contributor to the activity inducing chromosomal aberrations of the water treated with an ozone/chlorine sequential process. Therefore, ozonation is one possible option to reduce the health risk caused by DBPs even in the presence of bromide.
Comparison of different advanced oxidation process to reduce toxicity and mineralisation of tannery wastewater
Authors: Schrank S.G. , José H.J. , Moreira R.F.P.M. , Schröder H. Fr.
Published: May 2018

Many organic compounds contained in wastewater are resistant to conventional chemical and/or biological treatment. Because of this reason different degradation techniques are studied as an alternative to biological and classical physico-chemical processes. Advanced Oxidation Processes (AOPs) probably have developed to become the best options in the near future. AOP while making use of different reaction systems, are all characterised by the same chemical feature: production of OH radicals (*OH). The versatility of AOPs is also enhanced by the fact that they offer different possibilities for OH radical production, thus allowing them to conform to specific treatment requirements. The main problem with AOPs is their high cost. The application of solar technologies to these processes could help to diminish that problem by reducing the energy consumption required for generating UV radiation.

In this work, different AOPs (O3, TiO2/UV, Fenton and H2O2/UV) were examined to treat tannery wastewater or as a pre-treatment step for improving the biodegradation of tannery wastewater, at different pH and dosage of the chemicals. Under certain circumstances retardation in biodegradation and/or an increase in toxicity may be observed within these treatment steps. Two different bioassays (Daphnia magna and Vibrio fischeri) have been used for testing the progress of toxicity during the treatment. In parallel other objectives were to analyse and identify organic compounds present in the untreated wastewater and arising degradation products in AOP treated wastewater samples. For this purpose substance specific techniques, e.g., gas chromatography - mass spectrometry (GC-MS) in positive electron impact (EI(+)) mode and atmospheric pressure ionisation (API) in combination with flow injection analysis (FIA) or liquid chromatography - mass and tandem mass spectrometry (LC-MS or LC-MS-MS) were performed.
Toxic effect of pharmaceuticals on methanogenesis
Authors: Fountoulakis M. , Drillia P. , Stamatelatou K. , Lyberatos G.
Published: May 2018

Pharmaceuticals present in sewage may inhibit the biological processes in a sewage treatment plant. In this work, the toxic-effect of six pharmaceuticals (carbamazepine, sulfamethoxazole, propranolol hydrochloride, diclofenac sodium, ofloxacin and clofibric acid) on the anaerobic digestion process is assessed. Acetoclastic methanogenes are the most sensitive group of microorganisms participating in the anaerobic digestion process. Appropriate toxicity tests for these microorganisms were then based on assessing the impact of pharmaceuticals on the specific methanogenic activity (SMA) of the anaerobic biomass. The toxicity was expressed by the IC80 and IC50 values, i.e. the concentration at which bioactivity was 80% and 50% of the control, respectively. Results showed that the pharmaceuticals tested caused a mild inhibition to the methanogenes in most cases, related directly to the tendency of the compounds to adsorb on the anaerobic biomass.
On the effect of pharmaceuticals on bacterial nitrite oxidation
Authors: Dokianakis S.N. , Kornaros M.E. , Lyberatos G.
Published: May 2018

Pharmaceuticals or their metabolites are partially excreted with urine or faeces ending up in raw sewage. Many of these substances are not biodegradable and their presence in influents of municipal wastewater treatment plants may cause adverse effects to sensitive biological processes such as nitrification, while on the other hand, they may go through the activated sludge process unreacted. The second step of nitrification, i.e. oxidation of nitrite to nitrate is particularly sensitive. Inhibition of this step under uncontrolled conditions may lead to accumulation of nitrite nitrogen in the plant effluent, a form of nitrogen which is particularly toxic. The effects caused by the presence of seven different pharmaceuticals to a culture of nitrite-oxidizing bacteria isolated from activated sludge are presented. These pharmaceuticals were ofloxacin, propranolol, clofibrate, triclosan, carbamazepine, diclofenac and sulfamethoxazole. Different effects were observed for each of the pharmaceuticals tested in this study. In the cases of ofloxacin and sulfamethoxazole significant inhibition was observed. Triclosan presented a substantial inhibitory effect on the substrate (nitrite) reduction rate. The long-term effect of triclosan on nitrite oxidizers was also examined in a CSTR reactor and conclusions were drawn regarding the reversibility of the inhibition caused by this compound.
Assessment of microbial natural attenuation in groundwater polluted with gasworks residues
Authors: Schulze S. , Tiehm A.
Published: May 2018

Intrinsic biodegradation, representing the key process in Natural Attenuation, was examined at a tar-oil polluted disposal site. Methods to assess microbial natural attenuation of BTEX and PAH included analysis of groundwater hydrochemistry, pollutant profiles, composition of the microflora, and microcosm studies. In the polluted groundwater downgradient the disposal site, oxygen and nitrate were only available adjacent to the groundwater table and at the plume fringes. In the anaerobic core of the plume, a sequence of predominating redox zones (methanogenic, sulphate-reducing, Fe(III)-reducing) was observed. Changing pollutant profiles in the plume indicated active biodegradation processes, e.g. biodegradation of toluene and naphthalene in the anaerobic zones. High numbers of microorganisms capable of growing under anaerobic conditions and of aerobic pollutant degrading organisms confirmed the impact of biodegradation at this site.

In microcosm studies, the autochthonous microflora utilised toluene, ethylbenzene, and naphthalene under sulfate- and Fe(III)-reducing conditions. Additionally, benzene and phenanthrene were degraded in the presence of Fe(III). Under aerobic conditions, all BTEX and PAH were rapidly degraded. The microcosm studies in particular were suitable to examine the role of specific electron acceptors, and represented an important component of the multiple line of evidence concept to assess natural attenuation.
Re-evaluation and reconstruction of water purification system using soil I. Assessment of soil as a sorbent of humic substances and phosphate ion
Authors: Fujikawa Y. , Hamasaki T. , Sugahara M. , Ozaki H. , Prasai G. , Yano T. , Imada R. , Tainaka Y. , Nakamura W. , Haruki F.
Published: May 2018

The purpose of our study is to develop a treatment procedure for humic substances (HS hereafter) and phosphate ion in wastewater and environmental water by percolation of the water through a constructed soil layer at the hydraulic loading of a few metres per day. In the present work, batch sorption tests were conducted for more than 80 samples of soil, sludge, mineral and organic materials in order to find good sorbents for fulvic acid (FA hereafter) and phosphate ion. The results showed that the sorption of FA was high for some charcoal, and apatite and goethite minerals. Comparatively high sorption of FA was found for some Andosols and volcanic ash soil. Significant sorption of phosphate ion, on the other hand, was found for various types of soil, sludge from water treatment plants and some waste materials. The linear isotherm was obtained for the sorption of FA to a charcoal, apatite and goethite minerals, and Andosols.
Biological removal of NOx from flue gas
Authors: Kumaraswamy R. , Muyzer G. , Kuenen J.G. , Loosdrecht M.C.M.
Published: May 2018

BioDeNOx is a novel integrated physico-chemical and biological process for the removal of nitrogen oxides (NOx) from flue gas. Due to the high temperature of flue gas the process is performed at a temperature between 50-55°C. Flue gas containing CO2, O2, SO2 and NOx, is purged through Fe(II)EDTA2- containing liquid. The Fe(II)EDTA2- complex effectively binds the NOx; the bound NOx is converted into N2 in a complex reaction sequence. In this paper an overview of the potential microbial reactions in the BioDeNOx process is discussed. It is evident that though the process looks simple, due to the large number of parallel potential reactions and serial microbial conversions, it is much more complex. There is a need for a detailed investigation in order to properly understand and optimise the process.
Nitrogen removal from pharmaceutical manufacturing wastewater via nitrite and the process optimization with on-line control
Authors: Li Y.Z. , Peng C.Y. , Peng Y.Z. , Wang P.
Published: May 2018

In this study, laboratory scale experiments were conducted to investigate the nitrogen removal from pharmaceutical manufacturing wastewater. The results indicate that by selective inhibition of free ammonia on oxidizers, nitrogen removal can be achieved by nitritation and denitritation process. The nitrite ratio was above 98% in the aerobic stage and the nitrogen removal efficiency was about 99%. The complete ammonia removal corresponded exactly to the “Ammonia Valley” in the pH versus time graphic and the anoxic reaction was completed when the “Nitrite Knee” appeared in the ORP versus time graphic. Optimization of the SBR cycle by step-feed and on-line control with pH and ORP strategy allowed the carbon and energy saving. The easy operation and the low cost make the SBR system an interesting option for the biological nitrogen removal from the pharmaceutical manufacturing wastewater.
Phosphorus removal under anoxic conditions in a continuous-flow A2N two-sludge process
Authors: Wang Y.Y. , Peng Y.Z. , Li T.W. , Ozaki M. , Takigawa A. , Wang S.Y.
Published: May 2018

The Anaerobic-Anoxic/Nitrification (A2N) system is a continuous-flow, two-sludge process in which Poly-P bacteria are capable of taking up phosphate under anoxic conditions using nitrate as an electron acceptor. The process is very efficient because it maximizes the utilization of organic substrate for phosphorus and nitrogen removal. An experimental lab-scale A2N system fed with domestic sewage was tested over a period of 260 days. The purpose of the experiment was to examine phosphorus removal capacity of a modified A2N two-sludge system. Factors affecting phosphorus and nitrogen removal by the A2N system were investigated. These factors were the influent COD/TN ratio, Sludge Retention Time (SRT), Bypass Sludge Flow rate (BSF) and Return Sludge Flow rate (RSF). Results indicated that optimum conditions for phosphorus and nitrogen removal were the influent COD/TN ratio around 6.49, the SRT of 14 days, and the BSF and RSF were fixed at about 26-33% of influent flow rate.
Application of Methanobrevibacter acididurans in anaerobic digestion
Authors: Savant D.V. , Ranade D.R.
Published: May 2018

To operate anaerobic digesters successfully under acidic conditions, hydrogen utilizing methanogens which can grow efficiently at low pH and tolerate high volatile fatty acids (VFA) are desirable. An acid tolerant hydrogenotrophic methanogen viz. Methanobrevibacter acididurans isolated from slurry of an anaerobic digester running on alcohol distillery wastewater has been described earlier by this lab. This organism could grow optimally at pH 6.0. In the experiments reported herein, M. acididurans showed better methanogenesis under acidic conditions with high VFA, particularly acetate, than Methanobacterium bryantii, a common hydrogenotrophic inhabitant of anaerobic digesters. Addition of M. acididurans culture to digesting slurry of acidogenic as well as methanogenic digesters running on distillery wastewater showed increase in methane production and decrease in accumulation of volatile fatty acids. The results proved the feasibility of application of M. acididurans in anaerobic digesters.
Treatment of landfill leachate by a pilot-scale modified Ludzack-Ettinger and sulfur-utilizing denitrification process
Authors: Bae J.-H. , Lee I.-S. , Jang M.-S. , Ahn K.-H. , Lee S.-H.
Published: May 2018

Nitrogen removal efficiency of a pilot-scale system consisted of Modified Ludzack-Ettinger (MLE) followed by sulfur-utilizing denitrification (SUDNR) process was evaluated with a landfill leachate. For SUDNR, a down-flow mode sulfur packed bed reactor (SPBR) filled with sulfur and limestone particles was used. Although total nitrogen removal efficiency of the MLE process was about 80% at the recycle ratio of 4, effluent contained 350-450 mg/L NO3--N. Up to a loading rate of 1.2 kg NO3--N/m3-day, the SPBR could achieve complete removal of nitrate, and nitrate removal rate was kept to that level even at higher loading rate. When a COD/N ratio of MLE process was maintained at 2 instead of 4, more organics with molecular weight less than 500 were utilized for heterotrophic denitrification although denitrification was not complete with the lack of electron donors. Clogging in the SPBR, mainly by the accumulation of nitrogen gas in the pores, could easily be removed by introducing the effluent in an upward direction for 1 min at 1 hr intervals. The proposed treatment system could achieve nitrate free effluent with a slight increase in chemical cost. Furthermore, depending on further COD removal requirement after biological treatment, the proposed treatment system can be an economical solution.
Experiences with a large-size WWTP based on activated sludge-biofiltration processes: 25 months of operation
Authors: Licskó I. , Csanád Szabó G. , Melicz Z.
Published: May 2018

The South-Budapest Wastewater Treatment Plant (SBWWTP) had been operated as a high-load activated sludge (AS) plant since the middle of the 60s. According to the requirements proposed by the water authorities the treatment process had to be upgraded into nutrient (phosphorus and nitrogen) removal. The upgrade of the plant comprised implementation of BIOFOR type nitrifying (NP) and post-denitrifying (DN) biofilters downstream of the AS stage. Phosphorus removal was obtained by chemical precipitation that can be done at five different points for feeding ferric-sulfate (Fe2(SO4)3). Partial flow recirculation was administered from the nitrifying BIOFOR unit ahead of the AS basin for pre-denitrification utilizing raw wastewater as carbon source. The plant performance was monitored since the test operation period for 25 months. Experience revealed that significant nitrification occurs in the high-load activated sludge basin originally designed for carbon removal. During the summer period (characterized by temperature of 20-25°C) about 37-42% ammonium conversion rate was observed in the reactor. The decreasing temperature in the wintertime resulted in lower nitrification rates, of about 6-10%. The combined activated sludge-biofiltration process proved its viability in the removal of organic matter, nitrogen and phosphorus. In this special configuration the AS system plays a key role in the nitrogen and organic matter removal.
Hybrid membrane systems for secondary effluent polishing for unrestricted reuse for agricultural irrigation
Authors: Oron G. , Bick A. , Gillerman L. , Manor Y.
Published: May 2018

Field experiments are in progress for secondary wastewater upgrading for unrestricted utilization for agricultural irrigation. The integrative approach of secondary effluent polishing is based on using a hybrid UltraFiltration (UF) and Reverse Osmosis (RO) membrane pilot system with a capacity of around 1 m3/hr. The UF effluent is used to feed the RO membranes. The RO permeate is subsequently applied for vegetable irrigation. Field results indicate the importance of the UF component in the removal of the organic matter and the pathogens that are still contained in the secondary effluent. Under specific conditions, when the dissolved solids content is relatively low, regarding sanitary and health aspects, the UF effluent can be applied for unrestricted irrigation. During the RO stage most nutrients are removed, allowing application of the effluent without jeopardizing the soil fertility and the aquifers. Preliminary economic assessment indicates that the extra cost for effluent polishing via the UF stage only is in the range of 5 to 15 US cents/m3. The extra cost for the RO stage is also assessed at 10 to 25 US cents/m3. The additional cost depends to a large extent on the quality of the incoming raw secondary effluent and local requirements of the command region.
Energy saving processes for nitrogen removal in organic wastewater from food processing industries in Thailand
Authors: Johansen N.H. , Suksawad N. , Balslev P.
Published: May 2018

Nitrogen removal from organic wastewater is becoming a demand in developed communities. The use of nitrite as intermediate in the treatment of wastewater has been largely ignored, but is actually a relevant energy saving process compared to conventional nitrification/denitrification using nitrate as intermediate. Full-scale results and pilot-scale results using this process are presented. The process needs some additional process considerations and process control to be utilized. Especially under tropical conditions the nitritation process will round easily, and it must be expected that many AS treatment plants in the food industry already produce NO2-N. This uncontrolled nitrogen conversion can be the main cause for sludge bulking problems. It is expected that sludge bulking problems in many cases can be solved just by changing the process control in order to run a more consequent nitritation. Theoretically this process will decrease the oxygen consumption for oxidation by 25% and the use of carbon source for the reduction will be decreased by 40% compared to the conventional process.
Six years of operation of a fluidised bed reactor for denitrification
Authors: Harri A. , Bosander J.
Published: May 2018

At Himmerfjärden wastewater treatment plant, a fluidised bed reactor for nitrogen removal has been operated since 1997. Despite its small footprint, the system enables a far-reaching nitrogen removal. The current nitrate reduction in the reactor is 95%. The reduction of total nitrogen at the wastewater treatment plant is 80-90% at normal operation. The concentration of nitrate in the effluent is easily controlled by changing the dose of carbon. As part of a series of full-scale experiments, the plant has, for the last two years, been operated without denitrification for a couple of months during spring/summer, in order to benefit a favourable N/P-ratio in the recipient and to counteract the growth of nitrogen fixing blue-green algae. When resuming the dosage of carbon, full denitrification was re-established in about two weeks. Important factors to take into consideration when operating the fluidised bed reactor are the abrasive characteristics of the carrier material (sand), the increased concentration of suspended solids in the effluent, and the importance of a suitable N/P-ratio in the influent, as lack of phosphorus might cause an uncontrolled microbiological growth.