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1.
J Environ Manage ; 304: 114295, 2022 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-35021589

RESUMEN

This study investigated the impact of seasonal variation and operating conditions on recovery of potable quality water from municipal wastewater effluent using an integrated algal treatment process with a dual forward osmosis (FO)-reverse osmosis (RO) membrane system. Pilot study of the algal process treating primary effluent validated the technical viability and seasonal performance during warm weather (May to October, 25-55 °C) using an extremophilic algal strain Galdieria sulphuraria, and during cold weather (November to April, 4-17 °C) using polyculture strains of algae and bacteria. Algal effluents from both seasons were used as the feed solution for the laboratory FO-RO study. In addition, pilot-scale FO-RO experiments were conducted to compare the system performance during treatment of algal effluent and secondary effluent from the conventional treatment facility. At 90% water recovery, the FO-RO achieved over 90% overall rejection of major ions and organic matter using the bench-scale system and over 99% rejection of all contaminants in pilot-scale studies. Detailed water quality analysis indicated that the product water from the integrated system met both the primary and secondary drinking water standards. This study demonstrated that the FO-RO system can be engineered as a viable alternative to treat algal effluent and secondary effluent for potable water reuse independent of seasonal variations and operating conditions.


Asunto(s)
Agua Potable , Purificación del Agua , Membranas Artificiales , Ósmosis , Proyectos Piloto , Aguas Residuales
2.
J Eur Acad Dermatol Venereol ; 36 Suppl 2: 26-34, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34979590

RESUMEN

The exposome has an impact on skin from life-long exposure. Acute short-term exposure to exposome stressors can also alter skin functions such as skin physical barrier and immune defenses, leading to skin dryness, sensitivity, flares of inflammatory skin conditions, or viral reactivations. Probiotics are defined as live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host. An extract produced by lysing Vitreoscilla filiformis (VfeV) cultured in Vichy volcanic mineralizing water (VVMW) has properties of probiotic fractions. In this review, we present in vivo and ex vivo studies with a dermocosmetic formulation containing 80% VVMW, 5% VfeV, 4% niacinamide (vitamin B3), 0.4% hyaluronic acid, and 0.2% vitamin E (M89PF) to evaluate the clinical efficacy in preventing and repairing stressed skin. Skin barrier benefits of M89PF were shown in studies after the skin was exposed to sudden thermal changes, after skin irritation by tape stripping, and in sleep-deprived women. M89PF significantly accelerated skin renewal compared to untreated skin. Skin antioxidant defense activity of M89PF was shown after exposure to stress from UVA plus cigarette smoke aggression. Skin microbiome recovery after acute stress from a harsh cleanser was significantly better in M89PF-treated skin compared to bare skin. Clinical benefits of M89PF on correcting clinical signs of stressed skin were shown in both Caucasian and Asian women exposed to a stressful lifestyle and various external (pollution, tobacco smoking, solar radiation) and internal (poor sleep, stressful work, unbalanced diet, and alcohol consumption) exposome factors. M89PF also showed depigmenting properties on dark spots in Asian women. Further clinical studies are now warranted to evaluate the efficacy of M89PF as adjuvant care to prevent and repair skin barrier disruption and reinforce skin defenses in skin exposed to acute stresses.


Asunto(s)
Cosméticos , Ácido Hialurónico , Niacinamida , Piel/efectos de los fármacos , Vitamina E , Vitreoscilla , Femenino , Humanos , Crema para la Piel , Agua
3.
Water Environ Res ; 94(1): e1685, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35048438

RESUMEN

The current study was aimed to designed laboratory scale constructed wetland (CW) for the treatment of domestic wastewater under temperature range (18-38°C) and hydraulic retention times (24 and 48 h). Besides, the soil of vegetative unit of CW was assessed using conventional culturing techniques, and 13 different bacterial species (Escherichia coli, Micrococcus, Pseudomonas, Proteus, Klebsiella, Streptococcus, Alcaligenes, Salmonella, Bacillus, Enterobacter, Staphylococcus, Shigella and Corynebacterium spp.) were determined. The pathogenic microbial load was high in influent samples, but after treatment, about 73.1-99.7% and 43.5-86.7% reduction in CFU/ml and MPN/100 ml index, respectively, were observed. Moreover, the organic loads in terms of COD, TDS, TSS, and turbidity were high in all influent samples, but after treatment, average percentage removal in different physico-chemical parameters was observed during overall treatment operations, that is, COD (59.7-65.6%), TDS (59.6-76.8%), TSS (64.9-76.7%), and turbidity (72.7-91.6%), while pH of the effluent samples was observed in the prescribed limits. It was concluded that laboratory scale CW using natural flora Paspalidium flavidum and bacterial species was efficient in the reduction of different pollution indicators and hence a best option to be modified on pilot-scale for wastewater treatment in the rural regions of Peshawar. PRACTITIONER POINTS: Role of retention times on performance of CW were studied. The commonly existing vegetation was utilized to treat domestic waste water. Both vegetations and HRT are key ingredients in obtaining high treatment efficiency.


Asunto(s)
Aguas Residuales , Purificación del Agua , Poaceae , Eliminación de Residuos Líquidos , Aguas Residuales/análisis , Humedales
4.
Huan Jing Ke Xue ; 43(1): 26-36, 2022 Jan 08.
Artículo en Chino | MEDLINE | ID: mdl-34989487

RESUMEN

In recent years, solid waste iron sludge (red mud, iron-containing water treatment residues, and iron-rich sludge) has been widely used to remove pollutants in the water environment; however, the difficulty of separating powdered iron sludge from the water environment media makes it impossible to apply it as a water treatment material on a large scale, and preparing iron sludge into magnetic materials that are easy to be separated is one of the effective strategies to solve this bottleneck. According to the existing research on iron sludge-based magnetic materials at home and abroad, the preparation methods of magnetic materials using iron sludge as raw materials are summarized, including a series of methods, including the thermal decomposition method, hydrothermal and solvothermal method, co-precipitation method, reduction roasting method, and carbonization method. Additionally, it is pointed out that the currently commonly used preparation methods are thermal decomposition, hydrothermal and solvothermal, and co-precipitation. In addition, the performance and application of these magnetic materials as adsorbents or catalysts in water treatment are also summarized. In general, iron sludge-based magnetic materials can better absorb heavy metals and organic pollutants in water. The main adsorption mechanisms are complexation, electrostatic interaction, reduction, cation exchange, and precipitation. As a catalyst, it can efficiently oxidize and degrade organic pollutants by generating strong oxidizing substances:SO4-· and ·OH. Although there have been many studies on the preparation and application of iron sludge-based magnetic materials, because the raw material iron sludge contains many impurities, the magnetic materials prepared from iron sludge also have certain impurities. Therefore, it is still necessary to strengthen the research on the safety of iron sludge-based magnetic materials in the future to further ensure that they can be used as environmentally friendly materials for water environment restoration.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Hierro , Fenómenos Magnéticos , Aguas del Alcantarillado , Contaminantes Químicos del Agua/análisis
5.
Huan Jing Ke Xue ; 43(1): 409-415, 2022 Jan 08.
Artículo en Chino | MEDLINE | ID: mdl-34989525

RESUMEN

A new type of zeolite-suspended packing was developed by using zeolite as an important raw material, which was then used to start the zeolite moving bed biofilm reactor (ZMBBR). ZMBBR was compared with the ceramsite moving bed biofilm reactor (CMBBR) packed with ordinary ceramsite-suspended packing to investigate the different nitritation performance. The results showed that stable nitritation was successfully achieved in two reactors by the inhibitory effect of free ammonia (FA), and both of their nitrite accumulation rates (NAR) reached 90%; due to the adsorption of zeolite to ammonium, ZMBBR relieved the inhibition of FA on AOB faster than CMBBR and achieved nitritation earlier; CMBBR and ZMBBR could maintain long-term stable nitrosation when ρ(NH4+-N) was 350 mg·L-1 and 1050 mg·L-1 and NPRAVG was 0.43 kg·(m3·d)-1 and 1.26 kg·(m3·d)-1, respectively, and ARECMBBR=82.21% and AREZMBBR=88.85%. In the process of the influent ρ(NH4+-N) gradually increasing from 250 mg·L-1 to 1250 mg·L-1, the maximum nitrite production rate (NPR) of CMBBR was 0.5634 kg·(m3·d)-1; when ρ(FA) reached 166 mg·L-1 at the influent ρ(NH4+-N) of 750 mg·L-1, CMBBR broke down for the heavy inhibition of FA. The maximum NPR of ZMBBR was 1.800 kg·(m3·d)-1, and the performance of ZMBBR was getting worse after the ρ(FNA) reached the peak value of 1.9611 mg·L-1 at the influent ρ(NH4+-N) of 1250 mg·L-1. Subsequently, the ρ(FA) of ZMBBR reached 158 mg·L-1 rapidly, the NPR dropped significantly to 0.9028 kg·(m3·d)-1, and the performance of ZMBBR became significantly worse. It was demonstrated by high-throughput sequencing analysis that the dominant strain of ZMBBR and CMBBR was Nitrosomonas_europaea, and the relative abundances of N._europaea in ZMBBR and CMBBR were 11.15% and 10.92%, respectively.


Asunto(s)
Compuestos de Amonio , Purificación del Agua , Zeolitas , Amoníaco , Biopelículas , Reactores Biológicos , Nitritos , Nitrógeno , Oxidación-Reducción , Aguas Residuales
6.
J Environ Manage ; 302(Pt B): 114094, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34775334

RESUMEN

Algal organic matters (AOM) produced by cyanobacteria is an important part of the organic pollution and deterioration of water quality. Due to the complex composition, high solubility and easy dispersion of AOM, its flocculation characteristics become an important factor affecting the treatment for cyanobacteria-containing water. In this study, the cyanobacteria both in the Lab- and Taihu-environment were taken as research objects, aiming at the flocculation characteristic analysis of their extracellular organic matters (EOM) and intracellular organic matters (IOM) with the release risks. Results showed that EOM required more coagulant dosage than IOM and its removal effect was relatively lower. The complex water environment factors in Taihu Lake might cause easier separation of cyanobacterial AOM, which increased the removal efficiency of EOM and IOM by 11.05-26.18% and 8.54.-12.8%, respectively. The flocculation efficiency of cyanobacterial AOM was not only affected by the zeta potential driven charge neutralization, but also by the component distribution and content of AOM. Aromatic protein-like microbial metabolites were the main combination targets of coagulants rather than humic acids and fulvic acids. The wider floc particle size range and worse floc uniformity of cyanobacterial EOM was also one of the reasons for its poor coagulation effect. This paper provides an important theoretical basis and data support for the targeted flocculation and removal of cyanobacterial AOM.


Asunto(s)
Cianobacterias , Purificación del Agua , Floculación , Lagos , Calidad del Agua
7.
J Pharm Biomed Anal ; 208: 114465, 2022 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-34826673

RESUMEN

Pharmaceutical effluents are complex media containing hundreds of compounds including active ingredients, intermediate products and unknown impurities. Bringing an industrial wastewater treatment plant (WWTP) into compliance with European directives requires a thorough analysis of the effluent. In this study, we demonstrate how online comprehensive two-dimensional liquid chromatography (on-line LC × LC) hyphenated to high resolution mass spectrometry (HRMS) can be a powerful analytical methodology to monitoring the outlet water, by analysing the content of known molecules while characterizing unknown compounds. Reversed phase liquid chromatography (RPLC) was used in both dimensions, with a penta-fluoro-phenyl silica-based column at neutral pH in the first dimension (1D) and a C18 column at acidic pH in the second one (2D). The conditions were optimized for a total analysis time of 60 min. The variability of both retention times and peak areas was evaluated. The average standard deviation on retention times was found to be less than 0.1 s in 2D. The relative standard deviation on peak area was about 7% for run-to-run analysis. This analytical approach, applied to the pharmaceutical effluents before (inlet) and after (outlet) wastewater treatment permitted to detect 240 compounds. These included 27 priority pharmaceutical products, 8 of which were of very high priority and their concentrations could be compared to target values. The comparison of 2D-LC and 1D-LC approaches clearly highlights the power of on-line RPLC x RPLC technique, which allows both targeted quantitative analysis and non-targeted qualitative analysis of pharmaceutical effluents.


Asunto(s)
Preparaciones Farmacéuticas , Plantas Medicinales , Purificación del Agua , Cromatografía de Fase Inversa , Espectrometría de Masas , Agua
8.
J Environ Manage ; 302(Pt A): 114009, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34872175

RESUMEN

Green infrastructure (GI) is becoming a common solution to mitigate stormwater-related problems. Given the uncertain costs of GI relative to other stormwater management strategies, stakeholders investing in GI need performance-analysis tools that consider the full suite of benefits and the impacts of uncertainty to help justify GI expenditures. This study provides a quantitative and comparative analysis of GI benefits, including nutrient uptake from stormwater and air pollutant deposition. Economic costs and benefits of GI are assessed using two metrics, benefit-cost ratios (BCRs) and nutrient removal costs, at three scales: household, subwatershed, and watershed scale. Results from a case study in the state of Maryland show that the costs of nutrient uptake at the subwatershed scale can be lower than those at either the watershed or household scales. Moreover, rain gardens are far more efficient in stormwater treatment at the household scale in comparison to watershed scale, for which large-scale dry or wet basins are more efficient. Using a BCR metric, smaller subwatersheds show more promise, while using a nutrient removal cost metric indicates that upstream subwatersheds are more suitable for stormwater treatment. The results also show that implementation of GI at all potential pervious locations does not necessarily increase nutrient removal costs and that self-installation of rain gardens greatly reduces nutrient removal costs. Finally, the results show that using numerous small-sized rain garden practices in front of residential buildings yields lower nutrient removal costs in comparison to permeable pavements placed in parking lots and commercial buildings.


Asunto(s)
Lluvia , Purificación del Agua , Análisis Costo-Beneficio , Incertidumbre , Abastecimiento de Agua
9.
Bioresour Technol ; 344(Pt B): 126129, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34655783

RESUMEN

The ability of microalgae to grow in a broad spectrum of wastewaters manifests great potentials for removing contaminants from effluents of industries and urban areas. Since the post-treatment microalgae biomass is also a significant source of high-value products, microalgae-based wastewater treatment is an economical and sustainable solution to wastewater management. Adding more value, the integration of microalgae with living/non-living materials looks more promising. Microalgae-based treatment technology has certain limitations like high operational costs, problematic harvesting, large land requirements, and hindrance in photosynthesis due to turbid wastewater. These challenges need to be essentially addressed to achieve enhanced wastewater remediation. This review has highlighted the potential applications of microalgae in contaminant removal from wastewaters, simultaneous resource recovery, efficient microalgae-based hybrid systems along with bottlenecks and prospects. This state-of-the-art article will edify the role of microalgae in wastewater remediation, biomass valorization for bio-based products, and present numerous possibilities in strengthening the circular bioeconomy.


Asunto(s)
Microalgas , Purificación del Agua , Biocombustibles , Biomasa , Fotosíntesis , Aguas Residuales
10.
Bioresour Technol ; 344(Pt B): 126192, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34710609

RESUMEN

Bioaugmentation is an optimization method with great potential to improve the treatment effect by introducing specific strains into the biological treatment system. In this study, a comprehensive review of the mechanism of bioaugmentation from the aspect of microbial community structure, the optimization methods facilitating application as well as feasible approaches of scale-up application has been provided. The different contribution of indigenous and exogenous strains was critically analyzed, the relationship between microbial community variation and system performance was clarified. Operation regulation and immobilization technologies are effective methods to deal with the possible failure of bioaugmentation. The gradual expansion from lab-scale, pilot scale to full-scale, the transformation and upgrading of wastewater treatment plants through the combination of direct dosing and biofilm, and the application of side-stream reactors are feasible ways to realize the full-scale application. The future challenges and prospects in this field were also proposed.


Asunto(s)
Microbiota , Purificación del Agua , Biopelículas , Reactores Biológicos
11.
Bioresour Technol ; 344(Pt B): 126201, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34710611

RESUMEN

Enzymatic conversion of micropollutants into less-toxic derivatives is an important bioremediation strategy. This paper aims to critically review the progress in water and wastewater treatment by both free and immobilized enzymes presenting this approach as highly efficient and performed under environmentally benign and friendly conditions. The review also summarises the effects of inorganic and organic wastewater matrix constituents on enzymatic activity and degradation efficiency of micropollutants. Finally, application of enzymatic reactors facilitate continuous treatment of wastewater and obtaining of pure final effluents. Of a particular note, enzymatic treatment of micropollutants from wastewater has been mostly reported by laboratory scale studies. Thus, this review also highlights key research gaps of the existing techniques and provides future perspectives to facilitate the transfer of the lab-scale solutions to a larger scale and to improve operationability of biodegradation processes.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Enzimas Inmovilizadas , Eliminación de Residuos Líquidos , Aguas Residuales , Agua , Contaminantes Químicos del Agua/análisis
12.
Bioresour Technol ; 344(Pt B): 126249, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34732372

RESUMEN

Phthalates are well-known emerging contaminants that harm human health and the environment. Therefore, this review aims to discuss about the occurrence, fate, and phthalates concentration in the various environmental matrices (e.g., aquatic, sediment, soil, and sewage sludge). Hence, it is necessary to treat sources containing phthalates before discharging them to aqueous environment. Various advanced wastewater treatments including adsorption process (e.g., biochar, activated carbon), advanced oxidation processes (e.g., photo-fenton, ozonation, photocatalysis), and biological treatment (membrane bioreactor) have been successfully to address this issue with high removal efficiencies (70-95%). Also, the degradation mechanism was discussed to provide a comprehensive understanding of the phthalate removal for the reader. Additionally, key factors that influenced the phthalates removal efficiency of these technologies were identified and summarized with a view towards pilot-scale and industrial applications.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Humanos , Ácidos Ftálicos , Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aguas Residuales/análisis , Contaminantes Químicos del Agua/análisis
13.
Bioresour Technol ; 344(Pt B): 126272, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34737048

RESUMEN

Cattle farm wastewater, as a significant reservoir for antibiotic resistance genes (ARGs), has received wide attention. Intracellular and extracellular ARGs (iARGs and eARGs) were detected during wastewater treatment, including solid-liquid separation, anaerobic regulation, upflow anaerobic sludge blanket (UASB) digestion, an anoxic-oxic-anoxic-oxic (A2O2) process, a membrane bioreactor (MBR), and ozone disinfection. Ten abundant ARGs were chosen as the target ARGs according to metagenomic sequencing. The concentrations of the total target iARGs and eARGs were 6.12 × 107 and 3.24 × 106 copy numbers/mL in raw wastewater, and then 3.79 × 103 and 3.95 × 105 copy numbers/mL in final effluent, because UASB, A2O2, MBR and ozone disinfection can gradually reduce the concentrations of most ARGs. The concentrations of ARGs were positively correlated with almost all wastewater quality indicators. Positive correlation was also observed between iARGs and Bacteroidetes, Firmicutes and Spirochaetes, indicating that the bacteria in these three phyla might be the main hosts of ARGs. Wastewater quality indicators and bacterial community composition affected the distribution and removal of ARGs during cattle wastewater treatment.


Asunto(s)
Antibacterianos , Purificación del Agua , Animales , Antibacterianos/farmacología , Bovinos , Farmacorresistencia Microbiana/genética , Granjas , Genes Bacterianos/genética , Aguas Residuales/análisis
14.
Bioresour Technol ; 344(Pt B): 126274, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34737054

RESUMEN

Three-dimensional biofilm electrode reactors (3D-BERs) are highly efficient in refractory wastewater treatment. In comparison to conventional bio-electrochemical systems, the filled particle electrodes act as both electrodes and microbial carriers in 3D-BERs. This article reviews the conception and basic mechanisms of 3D-BERs, as well as their current development. The advantages of 3D-BERs are illustrated with an emphasis on the synergy of electricity and microorganisms. Electrode materials utilized in 3D-BERs are systematically summarized, especially the critical particle electrodes. The configurations of 3D-BERs and their integration with wastewater treatment reactors are introduced. Operational parameters and the adaptation of 3D-BERs to varieties of wastewater are discussed. The prospects and challenges of 3D-BERs for wastewater treatment are then presented, and the future research directions are proposed. We believe that this timely review will help to attract more attentions on 3D-BERs investigation, thus promoting the potential application of 3D-BERs in wastewater treatment.


Asunto(s)
Purificación del Agua , Biopelículas , Electrodos , Aguas Residuales
15.
Bioresour Technol ; 344(Pt B): 126245, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34743994

RESUMEN

The bioremediation of emerging pollutants in wastewater via algal biotechnology has been emerging as a cost-effective and low-energy input technological solution. However, the algal bioremediation technology is still not fully developed at a commercial level. The development of different technologies and new strategies to cater specific needs have been studied. The existence of multiple emerging pollutants and the selection of microalgal species is a major concern. The rate of algal bioremediation is influenced by various factors, including accidental contaminations and operational conditions in the pilot-scale studies. Algal-bioremediation can be combined with existing treatment technologies for efficient removal of emerging pollutants from wastewater. This review mainly focuses on algal-bioremediation systems for wastewater treatment and pollutant removal, the impact of emerging pollutants in the environment, selection of potential microalgal species, mechanisms involved, and challenges in removing emerging pollutants using algal-bioremediation systems.


Asunto(s)
Contaminantes Ambientales , Microalgas , Purificación del Agua , Biodegradación Ambiental , Aguas Residuales
16.
Bioresour Technol ; 344(Pt B): 126291, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34752884

RESUMEN

Biotransformation of trace-level organic micropollutants (OMPs) by complex microbial communities in wastewater treatment facilities is a key process for their detoxification and environmental impact reduction. Therefore, understanding the metabolic activities and mechanisms that contribute to their biotransformation is essential when developing approaches aiming to minimize their discharge. This review addresses the relevance of cometabolic processes and discusses the main enzymatic activities currently known to take part in OMPs removal under different redox environments in the compartments of wastewater treatment plants. Furthermore, the most common methodologies to decipher such enzymes are discussed, including the use of in vitro enzyme assays, enzymatic inhibitors, the analysis of transformation products and the application of several -omic techniques. Finally, perspectives on major challenges and future research requirements to improve OMPs biotransformation are proposed.


Asunto(s)
Contaminantes Químicos del Agua , Purificación del Agua , Reactores Biológicos , Biotransformación , Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aguas Residuales
17.
Bioresour Technol ; 344(Pt B): 126336, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34785331

RESUMEN

In this study, a radial basis function neural network (RBFNN) model was developed and implemented in a multi-objective optimization procedure to determine the optimal hydraulic loading rate (HLR), hydraulic retention time (HRT), and mass loading rates (MLR) for enhanced removal of nitrogen and phosphorus by an integrated surface flow treatment wetland-pond system treating drinking source water in Yancheng, China. Prior to modelling, the system's 6-year nitrogen and phosphorus removal efficiencies were found to trend downwards as effluent concentrations trended positively. Meanwhile, operating parameter interaction effects impacted final effluent quality. Thus, total nitrogen and total phosphorus removal were simulated by an RBFNN model with satisfactory R2 of 0.99 and 0.98 respectively. Optimal average HLR, HRT and MLR for 80% simultaneous removal efficiencies were subsequently determined to be 0.10860 ± 0.03 md-1, 30.43 ± 9.96 d and 306.416 ± 89.54 mgm-2d-1 respectively. The results highlight the feasibility of the RBFNN modelling based optimization procedure for treatment wetlands.


Asunto(s)
Purificación del Agua , Humedales , Redes Neurales de la Computación , Nitrógeno , Fósforo , Estanques , Eliminación de Residuos Líquidos
18.
Bioresour Technol ; 344(Pt B): 126322, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34785336

RESUMEN

Membrane bioreactor (MBR) has been widely implemented to advance wastewater treatment and reuse. Nevertheless, conventional MBRs with porous microfiltration or ultrafiltration membranes are not designed for the removal of micropollutants, which ubiquitously occur in wastewater at trace concentrations, but potentially exert detrimental impacts to the ecosystem. Several effective strategies have been applied to improve MBR performance for micropollutant removal, particularly the hydrophilic and recalcitrant compounds. These strategies mainly include the optimization of operational conditions, employment of high-retention membranes to replace porous ones, addition of functional materials into bioreactor, and integration of effluent purification processes. In particular, effluent purification by advanced oxidation processes (AOPs) and high-retention membranes can complement MBR to secure almost complete removal of micropollutants. Nevertheless, further research is still necessary to evaluate the technical and economic feasibility of these strategies, especially for long-term treatment performance, to screen the suitable techniques for industrial MBR applications.


Asunto(s)
Aguas Residuales , Purificación del Agua , Reactores Biológicos , Ecosistema , Membranas Artificiales , Eliminación de Residuos Líquidos
19.
Water Res ; 208: 117847, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34794020

RESUMEN

The inactivation of algae by a combined process of peracetic acid and ultraviolet irradiation (UV/PAA) was systematically investigated by choosing Microcystis aeruginosa as the reference algal species. Both hydroxyl (HO•) and organic radicals (RO•) contributed to the cell integrity loss and RO• played the dominant roles. The algae inactivation kinetics can be well fitted by the typical Hom model, showing that the inactivation kinetic curves followed a type of shoulder and exponential reduction. The initial shoulder might be induced by the protection from the cell wall. Although the results from the cell morphology, UV-vis spectra and fluorescence excitation-emission matrices analysis suggested the cell lysis and the release of algal organic matter (AOM) in the UV/PAA process, the AOM could be subsequently degraded. Humic acid (1 - 5 mg/L) inhibited the algal cell inactivation, and the presence of chloride (0.5 - 2 mM) had little effect on the cell viability reduction. However, the addition of bicarbonate (1 - 5 mM) promoted cell integrity loss. The UV/PAA process displayed better performance under the natural water background, demonstrating the extensive potential for the practical application of this approach. This study suggests that the UV/PAA process is an effective strategy for algae inactivation.


Asunto(s)
Microcystis , Purificación del Agua , Radical Hidroxilo , Ácido Peracético/farmacología , Rayos Ultravioleta
20.
Water Res ; 208: 117855, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34801818

RESUMEN

The present study provides an overall view of the effect of the ultrasound treatment on waste activated sludge (WAS) rheological and dewatering properties as well as its impact on the economic balance of a theoretical wastewater treatment plant. The results showed that ultrasonication at 27,000 kJ/kg TS increased the soluble protein concentration (> 100%), bound water content (∼25%), and capillary suction time (> 100%) of WAS. The molecular weight distribution of the extracellular polymeric substances (EPS) revealed that the ultrasound treatment solubilised a portion of the peptides and low-molecular-weight proteins. The thixotropic behaviour of the WAS was analysed by means of a rheological structural model that defines the time evolution of a structural parameter as a function of kinetic coefficients for the breakdown and build-up processes. The ultrasound treatment reduced the kinetic coefficients for the breakdown process and changed the fast speed of alignment of flocs because of the reduction of WAS structures. Similarly, the creep tests revealed that the ultrasound treatment at 27,000 kJ/kg TS reduced the initial elasticity (∼80%) and the zero-shear rate viscosity (∼60%), which means that the internal structure of the WAS loosened and disrupted. Finally, a techno-economic analysis showed that ultrasonication was not yet economically favourable since its implementation increased 14% the net cost for WAS treatment and disposal. However, a sensitivity analysis illustrated that increasing electricity revenue and reducing biosolids disposal costs through improvement in WAS biodegradability is important to make ultrasound implementation economically attractive.


Asunto(s)
Aguas del Alcantarillado , Purificación del Agua , Reología , Eliminación de Residuos Líquidos , Aguas Residuales , Agua
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