Degradation of pharmaceuticals in non-sterile urban wastewater by Trametes versicolor in a fluidized bed bioreactor

Occurrence and removal of transformation products of PPCPs and illicit drugs in wastewaters: a review

Pharmaceuticals and personal care products (PPCPs) along with illicit drugs (IDs) are newly recognized classes of environmental pollutants and are receiving considerable attention because of their environmental impacts: frequent occurrence, persistence and risk to aquatic life and humans. However, relatively little information is often available with regard to their possible biotic and abiotic transformation products (TPs). This lack of knowledge has resulted in a substantial amount of ongoing effort to develop methods and approaches that would assess their occurrence, degradability potential elimination mechanisms and efficiencies in sewage treatment plants as well as environmental and human health risks. In this article, an extensive literature survey was performed in order to present the current stage of knowledge and progress made in the occurrence of TPs of PPCPs and IDs in raw and treated wastewaters. Apart from the TPs resulting from structural transformations of the parent compound in the aquatic environment or in technological treatment facilities (e.g. sewage and drinking water treatment plants), free metabolites and drug conjugates formed during human metabolism have also been included in this review as they are also released into the aquatic environment through wastewaters. Their concentration levels were reported in influents and effluents of WWTPs, hospital effluents and their removals in the treatment plants were discussed. Finally, information on the toxicity of TPs has been compiled when available.

Identification of some factors affecting pharmaceutical active compounds (PhACs) removal in real wastewater. Case study of fungal treatment of reverse osmosis concentrate

Many technologies are being developed for the efficient removal of micropollutants from wastewater and, among them, fungal degradation is one of the possible alternative biological treatments. In this article, some factors that might affect pharmaceutically active compounds (PhACs) removal in a fungal treatment of real wastewater were identified in batch bioreactor treating reverse osmosis concentrate (ROC) from urban wastewater treatment plant (WWTP). We found that degradation of PhACs by Trametes versicolor was enhanced by addition of external nutrients (global removal of 44%). Moreover, our results point out that high aeration might be involved in the increase in the concentration of some PhACs. In fact, conjugation and deconjugation processes (among others) affect the removal assessment of emerging contaminants when working with real concentrations in comparison to experiments with spiked samples. Moreover, factors that could affect the quantification of micropollutants at lab-scale experiments were studied.

Capability of the natural microbial community in a river water ecosystem to degrade the drug naproxen

The present work aims at evaluating the ability of the River Tiber natural microbial community to degrade naproxen in water samples collected downstream from a wastewater treatment plant. For this purpose, different water microcosms were set up (microbiologically active vs sterile ones) and treated with naproxen (100 μg/L) alone or in the co-presence of gemfibrozil in order to evaluate if the co-presence of the latter had an influence on naproxen degradation. The experiment was performed in the autumn and was compared with the same experimental set performed in spring of the same year to highlight if seasonal differences in the river water influenced the naproxen degradation. Pharmaceutical concentrations and microbial analysis (total cell number, viability, and microbial community composition) were performed at different times in the degradation experiments. The overall results show that the natural microbial community in the river water had a key role in the naproxen degradation. In fact, although there was a transient negative effect on the natural microbial community in all the experiments (3 h after adding the pharmaceutical), the latter was able to degrade naproxen within about 40 days. On the contrary, no decrease in the pharmaceutical concentration was observed in the sterile river water. Moreover, the co-presence of the two drugs lengthened the naproxen lag phase. As regards the natural microbial community composition detected by Fluorescence in situ Hybridization, Alpha and Gamma-Proteobacteria increased when the pharmaceutical halved, suggesting their role in the degradation. This study shows that with the concentration studied, naproxen was degraded by the natural microbial populations collected from a river chronically contaminated by this pharmaceutical.

The ability of biologically based wastewater treatment systems to remove emerging organic contaminants--a review

Biologically based wastewater treatment systems are considered a sustainable, cost-effective alternative to conventional wastewater treatment systems. These systems have been used and studied for the treatment of urban sewage from small communities, and recently, it has been reported that they can also effectively remove emerging organic contaminants (EOCs). EOCs are a new group of unregulated contaminants which include pharmaceutical and personal care products, some pesticides, veterinary products, and industrial compounds among others that are thought to have long-term adverse effects on human health and ecosystems. This review is focused on reporting the ability of biologically based wastewater treatment systems to remove EOCs and the main elimination mechanisms and degradation processes (i.e., biodegradation, photodegradation, phytoremediation, and sorption) taking place in constructed wetlands, ponds, and Daphnia and fungal reactors.

Hybrid bioreactor (HBR) of hollow fiber microfilter membrane and cross-linked laccase aggregates eliminate aromatic pharmaceuticals in wastewaters

Widespread detection of numerous micropollutants including aromatic pharmaceuticals in effluents of wastewater treatment plants has prompted much research aimed at efficiently eliminating these contaminants of environmental concerns. In the present work, a novel hybrid bioreactor (HBR) of cross-linked enzymes aggregates of laccase (CLEA-Lac) and polysulfone hollow fiber MF membrane was developed for the elimination of acetaminophen (ACT), mefenamic acid (MFA) and carbamazepine (CBZ) as model aromatic pharmaceuticals. The MF alone showed removals of the three drugs varying approximately from 50 to 90% over the course of 8h in the filtrate of aqueous solution. Synergistic action of the MF and CLEA-Lac during operation achieved eliminations from aqueous solution of around 99%, nearly 100% and up to 85% for ACT, MFA and CBZ, respectively. Under continuous operation, the HBR demonstrated elimination rates of the drugs from filtered wastewater up to 93% after 72h for CBZ and near complete elimination of ACT and MFA was achieved within 24h of treatment. Concomitantly to the drugs eliminations in the wastewater, the CLEA-Lac exhibited 25% residual activity while being continuously recycled with no activity in the filtrate. Meanwhile, the filtrate flowrate showed only minor decline indicating limited fouling of the membrane.

Hospital wastewater treatment by fungal bioreactor: removal efficiency for pharmaceuticals and endocrine disruptor compounds

Hospital effluents contribute to the occurrence of emerging contaminants in the environment due to their high load of pharmaceutical active compounds (PhACs) and some endocrine disruptor compounds (EDCs). Nowadays, hospital wastewaters are co-treated with urban wastewater; however, the dilution factor and the inefficiency of wastewater treatment plants in the removal of PhACs and EDCs make inappropriate the co-treatment of both effluents. In this paper, a new alternative to pre-treat hospital wastewater concerning the removal of PhACs and EDCs is presented. The treatment was carried out in a batch fluidized bed bioreactor under sterile and non-sterile conditions with Trametes versicolor pellets. Results on non-sterile experiments pointed out that 46 out of the 51 detected PhACs and EDCs were partially to completely removed. The total initial PhAC amount into the bioreactor was 8185 μg in sterile treatment and 8426 μg in non-sterile treatment, and the overall load elimination was 83.2% and 53.3% in their respective treatments. In addition, the Microtox test showed reduction of wastewater toxicity after the treatment. Hence, the good efficiency of the fungal treatment regarding removal of the wide diversity of PhACs and EDCs detected in hospital effluents is demonstrated.

Re-inoculation strategies enhance the degradation of emerging pollutants in fungal bioaugmentation of sewage sludge

The use of Trametes versicolor has been partially successful in the removal of some pharmaceuticals from sewage sludge in laboratory-scale biopile systems. The application of two strategies for the re-inoculation of biomass was assessed during the fungal bioaugmentation of non-sterile sludge (42-d treatment) as an approach to improve the elimination of pharmaceuticals and other groups of emerging pollutants. Globally, the re-inoculation of biopiles with blended mycelium exerted a major effect on the removal of pharmaceuticals (86%), brominated-flame-retardants (81%) and UV filters (80%) with respect to the re-inoculation with additional lignocellulosic substrate colonized by the fungus (69-67-22%). The performance was better than that of the analogous non-re-inoculated systems that were assayed previously for the removal of pharmaceuticals. The results demonstrate the ability of T. versicolor to remove a wide spectrum of emerging micropollutants under non-sterile conditions, while re-inoculation appears to be a useful step to improve the fungal treatment of sludge.

Biodegradation of the X-ray contrast agent iopromide and the fluoroquinolone antibiotic ofloxacin by the white rot fungus Trametes versicolor in hospital wastewaters and identification of degradation products

This paper describes the degradation of the X-ray contrast agent iopromide (IOP) and the antibiotic ofloxacin (OFLOX) by the white-rot-fungus Trametes versicolor. Batch studies in synthetic medium revealed that between 60 and 80% of IOP and OFLOX were removed when spiked at approximately 12 mg L(-1) and 10 mg L(-1), respectively. A significant number of transformation products (TPs) were identified for both pharmaceuticals, confirming their degradation. IOP TPs were attributed to two principal reactions: (i) sequential deiodination of the aromatic ring and (ii) N-dealkylation of the amide at the hydroxylated side chain of the molecule. On the other hand, OFLOX transformation products were attributed mainly to the oxidation, hydroxylation and cleavage of the piperazine ring. Experiments in 10 L-bioreactor with fungal biomass fluidized by air pulses operated in batch achieved high percentage of degradation of IOP and OFLOX when load with sterile (87% IOP, 98.5% OFLOX) and unsterile (65.4% IOP, 99% OFLOX) hospital wastewater (HWW) at their real concentration (μg L(-1) level). Some of the most relevant IOP and OFLOX TPs identified in synthetic medium were also detected in bioreactor samples. Acute toxicity tests indicated a reduction of the toxicity in the final culture broth from both experiments in synthetic medium and in batch bioreactor.

Fungal biosynthesis of gold nanoparticles: mechanism and scale up

Gold nanoparticles (AuNPs) are a widespread research tool because of their oxidation resistance, biocompatibility and stability. Chemical methods for AuNP synthesis often produce toxic residues that raise environmental concern. On the other hand, the biological synthesis of AuNPs in viable microorganisms and their cell-free extracts is an environmentally friendly and low-cost process. In general, fungi tolerate higher metal concentrations than bacteria and secrete abundant extracellular redox proteins to reduce soluble metal ions to their insoluble form and eventually to nanocrystals. Fungi harbour untapped biological diversity and may provide novel metal reductases for metal detoxification and bioreduction. A thorough understanding of the biosynthetic mechanism of AuNPs in fungi is needed to reduce the time of biosynthesis and to scale up the AuNP production process. In this review, we describe the known mechanisms for AuNP biosynthesis in viable fungi and fungal protein extracts and discuss the most suitable bioreactors for industrial AuNP biosynthesis.

Fungal biosynthesis of gold nanoparticles: mechanism and scale up

Gold nanoparticles (AuNPs) are a widespread research tool because of their oxidation resistance, biocompatibility and stability. Chemical methods for AuNP synthesis often produce toxic residues that raise environmental concern. On the other hand, the biological synthesis of AuNPs in viable microorganisms and their cell-free extracts is an environmentally friendly and low-cost process. In general, fungi tolerate higher metal concentrations than bacteria and secrete abundant extracellular redox proteins to reduce soluble metal ions to their insoluble form and eventually to nanocrystals. Fungi harbour untapped biological diversity and may provide novel metal reductases for metal detoxification and bioreduction. A thorough understanding of the biosynthetic mechanism of AuNPs in fungi is needed to reduce the time of biosynthesis and to scale up the AuNP production process. In this review, we describe the known mechanisms for AuNP biosynthesis in viable fungi and fungal protein extracts and discuss the most suitable bioreactors for industrial AuNP biosynthesis.

Bioremediation of coking wastewater containing carbazole, dibenzofuran, dibenzothiophene and naphthalene by a naphthalene-cultivated Arthrobacter sp. W1

A naphthalene-utilizing bacterium, Arthrobacter sp. W1, was used to investigate the cometabolic degradation of carbazole (CA), dibenzofuran (DBF) and dibenzothiophene (DBT) using naphthalene as the primary substrate. Both the growing and washed cells of strain W1 could degrade CA, DBF, DBT, and naphthalene simultaneously and quickly. Inhibition kinetics confirmed that the presence of CA, DBF and DBT in the growing system would inhibit the cells growth and biodegradability of strain W1. The relationship between ln(C/C0) and time, and specific degradation rate and CA, DBF and DBT concentration could be described well by First-order and Michaelis-Menten kinetics. The treatment of real coking wastewater containing high concentration of phenol, naphthalene, CA, DBF, DBT and NH3-N was shown to be highly efficient by naphthalene-grown W1 coupling with activation zeolite. Toxicity assessment indicated the treatment of the coking wastewater by strain W1 coupling with activation led to less toxicity than untreated wastewater.