José R. Valéro

Membrane processes for removal of pharmaceutically active compounds (PhACs) from water and wastewaters

Pharmaceutically active compounds (PhACs), which find their way easily into the water sources, are emerging as a major concern for drinking water quality and aquatic species. Therefore, their removal from water sources is a priority from environmental point of view. During the past decade, different methods including membrane separation, adsorption systems and chemical transformation have been evaluated for removal of these compounds. This paper reviews different aspects of PhAC removal by using membrane separation processes, as they have been conventionally known to show high potential in the production of superior quality drinking and industrial water. In brief, osmosis membranes can efficiently remove almost all PhACs though its operational cost is relatively high and nanofiltration (NF) membranes are highly influenced by electrostatic and hydrophobic interaction. Moreover, the efficiency of membrane bioreactors (MBRs) is difficult to predict due to the complex interaction of compounds with microorganisms. To improve the performance and robustness of membrane technology, it is suggested to combine membranes with other systems, such as activated carbon and enzymatic degradation.

Adsorption of methylene blue on biochar microparticles derived from different waste materials

Biochar microparticles were prepared from three different types of biochar, derived from waste materials, such as pine wood (BC-PW), pig manure (BC-PM) and cardboard (BC-PD) under various pyrolysis conditions. The microparticles were prepared by dry grinding and sequential sieving through various ASTM sieves. Particle size and specific surface area were analyzed using laser particle size analyzer. The particles were further characterized using scanning electron microscope (SEM). The adsorption capacity of each class of adsorbent was determined by methylene blue adsorption tests in comparison with commercially available activated carbon. Experimental results showed that dye adsorption increased with initial concentration of the adsorbate and biochar dosage. Biochar microparticles prepared from different sources exhibited improvement in adsorption capacity (7.8±0.5 mg g(-1) to 25±1.3 mg g(-1)) in comparison with raw biochar and commercially available activated carbon. The adsorption capacity varied with source material and method of production of biochar. The maximum adsorption capacity was 25 mg g(-1) for BC-PM microparticles at 25°C for an adsorbate concentration of 500 mg L(-1) in comparison with 48.30±3.6 mg g(-1) for activated carbon. The equilibrium adsorption data were best described by Langmuir model for BC-PM and BC-PD and Freundlich model for BC-PW.

Encapsulation of ligninolytic enzymes and its application in clarification of juice.

The thermal stability, physico-chemical properties and effect on juice clarification of hydrogel formulations of ligninolytic enzymes from Phanerochaete chrysosporium were evaluated. The results showed that enzyme entrapment increase significantly (P<0.05) the thermal stability of enzymes at 4 and 75 °C. At 75 °C, maximum activity decreased to non detectable values of 7.9% for free laccase, manganese peroxidase (MnP), lignin peroxidase (LiP), respectively; to 94%, 97%, 93% for laccase, MnP and LiP entrapped into Polyacrylamide/pectin, 94%, 98%, 88% for laccase, MnP and LiP encapsulated respectively into polyacrylamide/ gelatine and to 87%, 91%, 87% for laccase, MnP and LiP entrapped, respectively into polyacrylamide/carboxymethylcellulose (CMC). When particle size and viscosity of the formulation increased, enzyme stability increased. The polyphenolic reduction and clarity amelioration in mixed juice of berry and pomegranate was more significant (p>0.05) using encapsulated enzymes treatment than free enzymes. This suggested that enzymatic treatment was efficient for the juice clarification.

Adsorption study of environmentally relevant concentrations of chlortetracycline on pinewood biochar.

The presence of pharmaceutically active compounds (PhACs) in water and wastewater has raised concerns because of potential environmental impacts and thus their removal is of high importance. The adsorption behavior of chlortetracycline (CTC) from aqueous solution on raw and activated pinewood biochar was studied at 298 K. The effect of initial pH of the solution was studied by performing the experiment at three different pHs (1, 5 and 9). At each pH, CTC showed varied electrostatic charge (+1, 0 and -1, respectively) which affected its adsorption. The results indicated that CTC followed Langmuir isotherm and the related parameters were calculated. Also, it was observed that the maximum adsorption occurred at pH1. The adsorption capacity of CTC for raw and activated biochar was at least 2.1 and 208.3mg/g adsorbent, respectively. The characteristics of biochars were studied using zeta potential analyzer, laser size analyzer and scanning electron microscopy (SEM). The results showed that raw and activated biochars are promising candidates for removal of CTC from water due to the acidic character of pinewood that can result in better interaction with ionizable compounds at lower pHs.

Industrial wastewaters and dewatered sludge: rich nutrient source for production and formulation of biocontrol agent, Trichoderma viride

Axenic cultivation of biocontrol fungus Trichoderma viride was conducted on a synthetic medium and different wastewaters and wastewater sludges in shake flasks to search for a suitable raw material resulting in higher biocontrol activity. Soluble starch based synthetic medium, dewatered municipal sludge, cheese industry wastewater sludge, pre-treated and untreated pulp and paper industry wastewater and slaughter house wastewater (SHW) were tested for T. viride conidia and protease enzyme production. The maximum conidia production followed the order, soluble starch medium (>109xa0c.f.u./mL), untreated pulp and paper industry wastewater (4.9xa0×xa0107xa0c.f.u./mL)xa0>xa0cheese industry wastewater (1.88xa0×xa0107xa0c.f.u./mL)xa0≈xa0SHW (1.63xa0×xa0107xa0c.f.u./mL)xa0>xa0dewatered municipal sludge (3.5xa0×xa0106xa0c.f.u./mL)xa0>xa0pre-treated pulp and paper industry wastewater (1.55xa0×xa0106xa0c.f.u./mL). The protease activity of T. viride was particularly higher in slaughterhouse wastewater (2.14xa0IU/mL) and dewatered municipal sludge (1.94xa0IU/mL). The entomotoxicity of soluble starch based synthetic medium was lower (≈6090xa0SBU/μL) in contrast to other raw materials. The entomotoxicity inversely decreased with carbon to nitrogen ratio in the growth medium and the conidia concentration and protease activity also contributed to the entomotoxicity. The residual c.f.u./g formulation of T. viride conidia were up to approximately, 90% after 1xa0month at 4xa0±xa01xa0°C and about 70% after 6xa0months at 25xa0±xa01xa0°C. Thus, production of T. viride conidia would help in marketability of low cost biopesticide from the sludge and safe reduction of pollution load.

Diclofenac in municipal wastewater treatment plant: quantification using laser diode thermal desorption—atmospheric pressure chemical ionization—tandem mass spectrometry approach in comparison with an established liquid chromatography-electrospray ionization–tandem mass spectrometry method

Diclofenac (DCF), a prevalent non-steroidal anti-inflammatory drug (NSAID) is often detected in wastewater and surface water. Analysis of the pharmaceuticals in complex matrices is often laden with challenges. In this study a reliable, rapid and sensitive method based on laser diode thermal desorption/atmospheric pressure chemical ionization (LDTD/APCI) coupled with tandem mass spectrometry (MS/MS) has been developed for the quantification of DCF in wastewater and wastewater sludge. An established conventional LC-ESI-MS/MS (liquid chromatography-electrospray ionization-tandem mass spectrometry) method was compared with LDTD-APCI-MS/MS approach. The newly developed LDTD-APCI-MS/MS method reduced the analysis time to 12s in lieu of 12 min for LC-ESI-MS/MS method. The method detection limits for LDTD-APCI-MS/MS method were found to be 270 ng L(-1) (LOD) and 1000 ng L(-1) (LOQ). Furthermore, two extraction procedures, ultrasonic assisted extraction (USE) and accelerated solvent extraction (ASE) for the extraction of DCF from wastewater sludge were compared and ASE with 95.6 ± 7% recovery was effective over USE with 86 ± 4% recovery. The fate and partitioning of DCF in wastewater (WW) and wastewater sludge (WWS) in wastewater treatment plant was also monitored at various stages of treatment in Quebec Urban community wastewater treatment plant. DCF exhibited affinity towards WW than WWS with a presence about 60% of DCF in WW in contrary with theoretical prediction (LogKow=4.51).

Toxicity of chlortetracycline and its metal complexes to model microorganisms in wastewater sludge.

Complexation of antibiotics with metals is a well-known phenomenon. Wastewater treatment plants contain metals and antibiotics, thus it is essential to know the effect of these complexes on toxicity towards microorganisms, typically present in secondary treatment processes. In this study, stability constants and toxicity of chlortetracycline (CTC) and metal (Ca, Mg, Cu and Cr) complexes were investigated. The calculated stability constants of CTC-metal complexes followed the order: Mg-CTC>Ca-CTC>Cu-CTC>Cr-CTC. Gram positive Bacillus thuringiensis (Bt) and Gram negative Enterobacter aerogenes (Ea) bacteria were used as model microorganisms to evaluate the toxicity of CTC and its metal complexes. CTC-metal complexes were more toxic than the CTC itself for Bt whereas for Ea, CTC and its metal complexes showed similar toxicity. In contrast, CTC spiked wastewater sludge (WWS) did not show any toxic effect compared to synthetic sewage. This study provides evidence that CTC and its metal complexes are toxic to bacteria when they are biologically available. As for WWS, CTC was adsorbed to solid part and was not biologically available to show measurable toxic effects.

Elucidating the Effect of Glycerol Concentration and C/N Ratio on Lipid Production Using Yarrowia lipolytica SKY7

The high demand for renewable energy and increased biodiesel production lead to the surplus availability of crude glycerol. Due to the above reason, the bio-based value addition of crude glycerol into various bioproducts is investigated; among them, microbial lipids are attractive. The present study was dedicated to find the optimal glycerol concentration and carbon/nitrogen (C/N) ratio to produce maximum lipid using Yarrowia lipolytica SKY7. The glycerol concentration (34.4 to168.2xa0g/L) and C/N ratio (25 to 150) were selected to investigate to maximize the lipid production. Initial glycerol concentration 112.5xa0g/L, C/N molar ratio of 100, and with 5xa0%xa0v/v inoculum supplementation were found to be optimum for biomass and lipid production. Based on the above optimal parameters, lipid concentration of 43.8xa0%xa0w/w with a biomass concentration of 14.8xa0g/L was achieved. In the case of glycerol concentration, the maximum Yp/s (0.192xa0g/g); Yx/s (0.43xa0g/g) was noted when the initial glycerol concentration was 112.5xa0g/L with C/N molar ratio 100 and inoculum volume 5xa0%xa0v/v. The glycerol uptake was also noted to increase with the increase in glycerol concentration. At low C/N ratio, the glycerol consumption was found to be high (79.43xa0g/L on C/N 25) whereas the glycerol consumption was observed to decrease when the C/N ratio was raised to 150 (40.8xa0g/L).

Rheological profile of diets produced using agro-industrial wastes for rearing codling moth larvae for baculovirus biopesticides

A rheological study of diets using the agro-industrial wastes (brewery wastewater and pomace waste) was carried out in order to obtain a diet most adapted to supply nutrients for growth of codling moth (CM) larvae. Nutritive capacity (g/L) of brewery wastewater (BWW) (25.5 ± 5.5 carbohydrates; 16.9 ± 2.1 proteins; 6 ± 1.6 lipids) and pomace waste (POM) (22.0 ± 0.03 carbohydrates; 11.3 ± 1.3 proteins; 2 ± 0.2 lipids) were essential and important as replacement or in association with other ingredients [soya flour (SF), wheat germ (WG), yeast extract (YE)] of the standard diet for the breeding of codling moth larvae. These diet additives also contributed to the preservation of texture and nutritive content of larvae diet. The eggs and CM larvae were grown on alternate diets under industrial conditions (16:8 h photoperiod; 25 ± 1°C and 50 ± 0.5 % of humidity). The higher assimilation of nutrients of the diets in BWW and control diet was observed by calculating the rate of hatching of eggs (0.48 to 0.71); larvae growth (0.23 to 0.4) and fertility (1.33 to 3 for control diet). The excellent growth and fertility rates of codling moth larvae were attributed to variations in viscosity (varying from 50 to 266 mPa.s−1), particle size (varying 24.3 μm in 88.05 μm with regard to 110 μm the control diet) and total solids (145.88 g/L POM + YE; 162.08 g/L BWW + YE; 162.2 g/L POM + WG; 173 g/L control; 174.3 g/L BWW + WG) diets. Lower viscosity favored improved diet due to ease of assimilation of nutrients. Thus, rheology is an important parameter during preparation of diets for growth of codling moth larvae as it will dictate the nutrient assimilation which is an important parameter of larvae growth.

Batch and fed-batch fermentation of Bacillus thuringiensis using starch industry wastewater as fermentation substrate

Bacillus thuringiensis var. kurstaki biopesticide was produced in batch and fed-batch fermentation modes using starch industry wastewater as sole substrate. Fed-batch fermentation with two intermittent feeds (at 10 and 20xa0h) during the fermentation of 72xa0h gave the maximum delta-endotoxin concentration (1,672.6xa0mg/L) and entomotoxicity (Tx) (18.5xa0×xa0106xa0SBU/mL) in fermented broth which were significantly higher than maximum delta-endotoxin concentration (511.0xa0mg/L) and Tx (15.8xa0×xa0106xa0SBU/mL) obtained in batch process. However, fed-batch fermentation with three intermittent feeds (at 10, 20 and 34xa0h) of the fermentation resulted in the formation of asporogenous variant (Spo−) from 36xa0h to the end of fermentation (72xa0h) which resulted in a significant decrease in spore and delta-endotoxin concentration and finally the Tx value. Tx of suspended pellets (27.4xa0×xa0106xa0SBU/mL) obtained in fed-batch fermentation with two feeds was the highest value as compared to other cases.