Comparison contrast-enhanced CT with contrast-enhanced US in diagnosing combined hepatocellular-cholangiocarcinoma: a propensity score-matched study.

OBJECTIVES: To develop and compare noninvasive models for differentiating between combined hepatocellular-cholangiocarcinoma (cHCC-CCA) and HCC based on serum tumor markers, contrast-enhanced ultrasound (CEUS), and computed tomography (CECT). METHODS: From January 2010 to December 2021, patients with pathologically confirmed cHCC-CCA or HCC who underwent both preoperative CEUS and CECT were retrospectively enrolled. Propensity scores were calculated to match cHCC-CCA and HCC patients with a near-neighbor ratio of 1:2. Two predicted models, a CEUS-predominant (CEUS features plus tumor markers) and a CECT-predominant model (CECT features plus tumor markers), were constructed using logistic regression analyses. Model performance was evaluated by the area under the curve (AUC), sensitivity, specificity, and accuracy. RESULTS: A total of 135 patients (mean age, 51.3 years ± 10.9; 122 men) with 135 tumors (45 cHCC-CCA and 90 HCC) were included. By logistic regression analysis, unclear boundary in the intratumoral nonenhanced area, partial washout on CEUS, CA 19-9 > 100 U/mL, lack of cirrhosis, incomplete tumor capsule, and nonrim arterial phase hyperenhancement (APHE) volume < 50% on CECT were independent factors for a diagnosis of cHCC-CCA. The CECT-predominant model showed almost perfect sensitivity for cHCC-CCA, unlike the CEUS-predominant model (93.3% vs. 55.6%, p < 0.001). The CEUS-predominant model showed higher diagnostic specificity than the CECT-predominant model (80.0% vs. 63.3%; p = 0.020), especially in the ≤ 5 cm subgroup (92.0% vs. 70.0%; p = 0.013). CONCLUSIONS: The CECT-predominant model provides higher diagnostic sensitivity than the CEUS-predominant model for CHCC-CCA. Combining CECT features with serum CA 19-9 > 100 U/mL shows excellent sensitivity. CRITICAL RELEVANCE STATEMENT: Combining lack of cirrhosis, incomplete tumor capsule, and nonrim arterial phase hyperenhancement (APHE) volume < 50% on CECT with serum CA 19-9 > 100 U/mL shows excellent sensitivity in differentiating cHCC-CCA from HCC. KEY POINTS: 1. Accurate differentiation between cHCC-CCA and HCC is essential for treatment decisions. 2. The CECT-predominant model provides higher accuracy than the CEUS-predominant model for CHCC-CCA. 3. Combining CECT features and CA 19-9 levels shows a sensitivity of 93.3% in diagnosing cHCC-CCA.

Radiomics and nomogram of magnetic resonance imaging for preoperative prediction of microvascular invasion in small hepatocellular carcinoma.

BACKGROUND: Microvascular invasion (MVI) of small hepatocellular carcinoma (sHCC) (≤ 3.0 cm) is an independent prognostic factor for poor progression-free and overall survival. Radiomics can help extract imaging information associated with tumor pathophysiology. AIM: To develop and validate radiomics scores and a nomogram of gadolinium ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) for preoperative prediction of MVI in sHCC. METHODS: In total, 415 patients were diagnosed with sHCC by postoperative pathology. A total of 221 patients were retrospectively included from our hospital. In addition, we recruited 94 and 100 participants as independent external validation sets from two other hospitals. Radiomics models of Gd-EOB-DTPA-enhanced MRI and diffusion-weighted imaging (DWI) were constructed and validated using machine learning. As presented in the radiomics nomogram, a prediction model was developed using multivariable logistic regression analysis, which included radiomics scores, radiologic features, and clinical features, such as the alpha-fetoprotein (AFP) level. The calibration, decision-making curve, and clinical usefulness of the radiomics nomogram were analyzed. The radiomic nomogram was validated using independent external cohort data. The areas under the receiver operating curve (AUC) were used to assess the predictive capability. RESULTS: Pathological examination confirmed MVI in 64 (28.9%), 22 (23.4%), and 16 (16.0%) of the 221, 94, and 100 patients, respectively. AFP, tumor size, non-smooth tumor margin, incomplete capsule, and peritumoral hypointensity in hepatobiliary phase (HBP) images had poor diagnostic value for MVI of sHCC. Quantitative radiomic features (1409) of MRI scans) were extracted. The classifier of logistic regression (LR) was the best machine learning method, and the radiomics scores of HBP and DWI had great diagnostic efficiency for the prediction of MVI in both the testing set (hospital A) and validation set (hospital B, C). The AUC of HBP was 0.979, 0.970, and 0.803, respectively, and the AUC of DWI was 0.971, 0.816, and 0.801 (P < 0.05), respectively. Good calibration and discrimination of the radiomics and clinical combined nomogram model were exhibited in the testing and two external validation cohorts (C-index of HBP and DWI were 0.971, 0.912, 0.808, and 0.970, 0.843, 0.869, respectively). The clinical usefulness of the nomogram was further confirmed using decision curve analysis. CONCLUSION: AFP and conventional Gd-EOB-DTPA-enhanced MRI features have poor diagnostic accuracies for MVI in patients with sHCC. Machine learning with an LR classifier yielded the best radiomics score for HBP and DWI. The radiomics nomogram developed as a noninvasive preoperative prediction method showed favorable predictive accuracy for evaluating MVI in sHCC.

Tailoring a novel hierarchical cheese-like porous biochar from algae residue to boost sulfathiazole removal.

Aquatic pollution caused by antibiotics poses a significant threat to human health and the ecosystem. Inspired from "Emmental Cheese" that owns lots of natural pores, we here fabricated a hierarchical cheese-like porous Spirulina residue biochar (KSBC) activated by KHCO3 for efficiently boosting the removal of sulfathiazole (STZ). Through learning form nature that the CO2 produced by bacteria can serve as the natural pore maker (like cheese-making), KHCO3 was thus selected as the gas generating agent in this study. The effect of adding KHCO3 on the surface properties of KSBC was comprehensively investigated. Benefiting from the activation, the KSBC with the mass ratio of 2:1 (2K-SBC) possessed the largest specific surface areas (1100 m2 g-1), which was approximately 81 times that of the original (not activated) Spirulina residue biochar (SBC) (13.56 m2 g-1). Moreover, 2K-SBC exhibited the maximum adsorption capacity for STZ (218.4 mg g-1), dramatically higher than the SBC (25.78 mg g-1). The adsorption kinetics and adsorption isotherms exhibited that the adsorption behavior of 2K-SBC for STZ was consistent with the pseudo-second-order and Langmuir models. Additionally, the adsorption thermodynamics revealed that the adsorption of STZ on 2K-SBC was spontaneous and exothermic. The pore-filling and electrostatic interaction were considered the main mechanism for the adsorption of STZ on 2K-SBC, whereas the π-π electron donor-acceptor (EDA) interaction and hydrogen bond would also partially contribute to the adsorption process.

FX5, a non-steroidal glucocorticoid receptor antagonist, ameliorates diabetic cognitive impairment in mice.

Diabetic cognitive impairment (DCI) is a common diabetic complication characterized by learning and memory deficits. In diabetic patients, hyperactivated hypothalamic-pituitary-adrenal (HPA) axis leads to abnormal increase of glucocorticoids (GCs), which causes the damage of hippocampal neurons and cognitive impairment. In this study we investigated the cognition-improving effects of a non-steroidal glucocorticoid receptor (GR) antagonist 5-chloro-N-[4-chloro-3-(trifluoromethyl) phenyl]thiophene-2-sulfonamide (FX5) in diabetic mice. Four weeks after T1DM or T2DM was induced, the mice were administered FX5 (20, 40 mg·kg-1·d-1, i.g.) for 8 weeks. Cognitive impairment was assessed in open field test, novel object recognition test, Y-maze test, and Morris water maze test. We showed that FX5 administration significantly ameliorated the cognitive impairments in both type 1 and 2 diabetic mice. Similar cognitive improvement was observed in diabetic mice following brain GR-specific knockdown by injecting AAV-si-GR. Moreover, AAV-si-GR injection occluded the cognition-improving effects of FX5, suggesting that FX5 functioning as a non-steroidal GR antagonist. In PA-treated primary neurons (as DCI model in vitro), we demonstrated that FX5 (2, 5, 10 µM) dose-dependently ameliorated synaptic impairment via upregulating GR/BDNF/TrkB/CREB pathway, protected against neuronal apoptosis through repressing GR/PI3K/AKT/GSK3ß-mediated tauopathy and subsequent endoplasmic reticulum stress. In LPS-treated primary microglia, FX5 dose-dependently inhibited inflammation through GR/NF-κB/NLRP3/ASC/Caspase-1 pathway. These beneficial effects were also observed in the hippocampus of diabetic mice following FX5 administration. Collectively, we have elucidated the mechanisms underlying the beneficial effects of non-steroidal GR antagonist FX5 on DCI and highlighted the potential of FX5 in the treatment of the disease.

Peroxymonosulfate activation by oxygen vacancies-enriched MXene nano-Co3O4 co-catalyst for efficient degradation of refractory organic matter: Efficiency, mechanism, and stability.

Cobalt-based catalysts have been widely explored in the degradation of organic pollutants based on peroxymonosulfate (PMS) activation. Herein, we report an MXene nano-Co3O4 co-catalyst enriched with oxygen vacancies (Ov) and steadily fixed in nickel foam (NF) plates, which is used as an efficient and stable PMS activator for the removal of 1,4-dioxane (1,4-D). Ti originating from MXene was doped into the Co3O4 crystal, generating large amounts of Ov, which could provide more active sites to enhance PMS activation and facilitate the transformation of Co2+ and Co3+, causing a high stability. As a result, the 1,4-D removal efficiency of the NF/MXene-Co3O4/PMS system (kapp: 2.41 min-1) was about four times higher than that of the NF/Co3O4/PMS system (kapp: 0.62 min-1). In addition, singlet oxygen was the predominant reactive oxygen species. Notably, the 1,4-D removal of the NF/MXene-Co3O4/PMS system was over 95% after 20 h operation in the single-pass filtration mode with only 3.72% accumulative Co leaching, showing excellent stability and reusability of NF/MXene-Co3O4. This work provides a defect engineering strategy to design a robust and stable catalytic system for water treatment, which expands the application of MXene in the field of environmental remediation.

Light source for comfortable lighting and trapping pests in tea gardens based on solar-like lighting.

A large amount of tea is produced every year. Tea is often harmed by pests during the cultivation process, causing great economic damage. In this paper, we simulated a kind of light source for comfortable lighting and trapping pests based on solar-like lighting. We investigated three combinations of white LEDs and monochromatic LEDs for solar-like trapping light. The optimal combination of white LEDs and monochromatic LEDs was determined by the production cost and the spectral phototaxis ratio. We used TracePro for the trapping light mixing design. The results show that the combination of the cold white LED and six kinds of monochromatic LEDs is the best for trapping pests. A light source for comfortable lighting and trapping pests based on solar-like lighting with the color temperature of 7285 k, color coordinates of (0.3052, 0.3031), and color rendering index of 70 is obtained. The trapping light can not only be used as functional lighting but can also be applied to reduce the use of pesticides and improve the quality of tea.

Production, properties, and catalytic applications of sludge derived biochar for environmental remediation.

Environment-friendly and cost-effective disposal and reutilization of sludge wastes are essential in wastewater treatment processes (WWTPs). Converting activated sludge into biochar via thermochemical treatment is a promising technology for waste management in WWTPs. This review summarizes the compositions of sludge, the dewatering methods, and the thermochemical methods whichinfluence the structures, chemistry, and catalytic performances of the derived biochar. Moreover, the physiochemical characteristics and chemical stability of sludge biochar are discussed. Catalytic applications of biochar are highlighted, including the reaction mechanisms and feasibility for catalytic removal of organic contaminants. High-temperature carbonized sludge biochar exhibits excellent performance for persulfate activation in advanced oxidation processes due to the graphitic carbon structure, newly-created active sites, and fine-tuned metal species. Therefore, the sludge biochar can be produced via cost-effective and eco-friendly approaches to immobilize harmful components from sludge and remediate organic pollution in wastewater, offering a sustainable route toward sludge reutilization into value-added products for water purification.

Optimizing the production of short and medium chain fatty acids (SCFAs and MCFAs) from waste activated sludge using different alkyl polyglucose surfactants, through bacterial metabolic analysis.

Alkyl polyglucose is an environmentally-friendly biosurfactant, which is able to enhance short-chain fatty acids production with different carbon chain lengths and concentrations, during sludge anaerobic fermentation. This presents a promising strategy for sludge re-utilization by effectively converting hazardous sludge into value-added compounds. The maximum yield of short-chain fatty acids produced from sludge was 479.3 and 462.2 mg COD/g VSS, following pretreatment with APG06 and APG1214, respectively. To the best of our knowledge, the short-chain fatty acid production performance by sludge fermentation reported here, achieved a higher level than reported in previous studies. Additionally, these findings indicate that the production of medium-chain fatty acids from sludge can be induced by alkyl polyglucoses. Finally, the microbial community and enzyme activity were also assessed to reveal the mechanism of short-/medium-chain fatty acids biosynthesis under alkyl polyglucose pretreatment. This study demonstrates that alkyl polyglucose provides an environmentally-friendly and effective strategy for enhancing the production of short-/medium-chain fatty acids from waste activated sludge. These findings are useful for the assessment of alkyl polyglucose-assisted production of short-/medium-chain fatty acids, as well as for understanding the interactions between short-/medium-chain fatty acids and microbial communities with key enzymes, to establish short-/medium-chain fatty acids metabolic pathways during sludge fermentation.

A novel clean production approach to utilize crop waste residues as co-diet for mealworm (Tenebrio molitor) biomass production with biochar as byproduct for heavy metal removal.

Proper management of waste crop residues has been an environmental concern for years. Yellow mealworms (larvae of Tenebrio molitor Linnaeus, 1758) are major insect protein source. In comparison with normal feed wheat bran (WB), we tested five common lignocellulose-rich crop residues as feedstock to rear mealworms, including wheat straw (WS), rice straw (RS), rice bran (RB), rice husk (RH), and corn straw (CS). We then used egested frass for the production of biochar in order to achieve clean production. Except for WS and RH, the crop residues supported mealworms' life activity and growth with consumption of the residues by 90% or higher and degraded lignin, hemicellulose and cellulose over 32 day period. The sequence of degradability of the feedstocks is RS > RB > CS > WS > RH. Egested frass was converted to biochar which was tested for metal removal including Pb(II), Cd(II), Cu(II), Zn(II), and Cr(VI). Biochar via pyrolysis at 600 °C from RS fed frass (FRSBC) showed the best adsorption performance. The adsorption isotherm fits the Langmuir model, and kinetic analysis fits the Pseudo-Second Order Reaction. The heavy metal adsorption process was well-described using the Intra-Particle Diffusion model. Complexation, cation exchange, precipitation, reduction, deposition, and chelation dominated the adsorption of the metals onto FRSBC. The results indicated that crop residues (WS, RS, RB, and CS) can be utilized as supplementary feedstock along with biochar generated from egested frass to rear mealworms and achieve clean production while generating high-quality bioadsorbent for environment remediation and soil conditioning.

An influent responsive control strategy with machine learning: Q-learning based optimization method for a biological phosphorus removal system.

Biological phosphorus removal (BPR) is an economical and sustainable processes for the removal of phosphorus (P) from wastewater, achieved by recirculating activated sludge through anaerobic and aerobic (An/Ae) processes. However, few studies have systematically analyzed the optimal hydraulic retention times (HRTs) in anaerobic and aerobic reactions, or whether these are the most appropriate control strategies. In this study, a novel optimization methodology using an improved Q-learning (QL) algorithm was developed, to optimize An/Ae HRTs in a BPR system. A framework for QL-based BPR control strategies was established and the improved Q function, Qt+1(st,st+1)=Qt(st,st+1)+k·[R(st,st+1)+γ·maxatQt(st,st+1)-Qt(st,st+1)] was derived. Based on the improved Q function and the state transition matrices obtained under different HRT step-lengths, the optimum combinations of HRTs in An/Ae processes in any BPR system could be obtained, in terms of the ordered pair combinations of the . Model verification was performed by applying six different influent chemical oxygen demand (COD) concentrations, varying from 150 to 600 mg L-1 and influent P concentrations, varying from 12 to 30 mg L-1. Superior and stable effluent qualities were observed with the optimal control strategies. This indicates that the proposed novel QL-based BPR model performed properly and the derived Q functions successfully realized real-time modelling, with stable optimal control strategies under fluctuant influent loads during wastewater treatment processes.

N-doped graphitic biochars from C-phycocyanin extracted Spirulina residue for catalytic persulfate activation toward nonradical disinfection and organic oxidation.

Biochars are low-cost and environmental-friendly materials, which are promising in wastewater treatment. In this study, biochars were manufactured from C-phycocyanin extracted (C-CP) Spirulina residue (SDBC) via thermal pyrolysis. Simultaneously, N-doping was also achieved from the protein in the algae for obtaining a high-performance carbocatalyst for peroxydisulfate (PDS) activation. The SDBC yielded large specific surface areas, nitrogen loading, and good conductivity, which demonstrated excellent oxidation efficiencies toward a wide array of aqueous microcontaminants. An in-depth mechanistic study was performed by integrating selective radical scavenging, solvent exchange (H2O to D2O), diverse organic probes, and electrochemical measurement, unveiling that SDBC/PDS did not rely on free radicals or singlet oxygen but a nonradical pathway. PDS intimately was bonded with a biochar (SDBC 900-acid, pyrolysis at 900 °C) to form a surface reactive complex that subsequently attacked an organic sulfamethoxazole (SMX) adsorbed on the biochar via an electron-transfer regime. During this process, the SDBC 900-acid played versatile roles in PDS activation, organic accumulation and mediating the electron shuttle from SMX to PDS. This nonradical system can maintain a superior oxidation efficiency in complicated water matrix and long-term stable operation. More importantly, the nonradical species in SDBC 900-acid/PDS system were capable of inactivating the bacteria (Escherichia coli) in wastewater. Therefore, the biochar based nonradical system can provide a mild and high-efficiency strategy for disinfection in waste and drinking water by green carbocatalysis. This study provides not only a value-added biochar catalyst for wastewater purification but also the first insight into the bacteria inactivation via nonradical oxidation.

Magnetic biochar catalysts from anaerobic digested sludge: Production, application and environment impact.

Regulated disposal or re-utilization of dewatered sludge is of economic benefits and can avoid secondary contamination to the environment; however, feasible and effective management strategies are still lacking. In this study, a peroxydisulfate/zero-valent iron (PDS-ZVI) system is proposed to destroy proteins in soluble extracellular polymeric substances (S-EPS) and loosely bound EPS (LB-EPS) in anaerobic digested sludge (ADS) to improve the dewaterability. Moreover, ADS derived biochars supported via iron oxides (Fe-ADSBC) were generated by dewatering and thermal annealing. Intriguingly, the iron species was discovered to gradually transform from Fe3O4 to FeO with increased pyrolysis temperatures from 600 to 1000 °C. The manipulated iron species on the biochar can remarkably impact the catalytic activity in PDS activation and degradation of sulfamethazine (SMT). The in situ radical scavenging and capturing tests revealed that the principal reactive oxygen species (ROS) in Fe-ADSBC/PDS system experienced a variation from OH into SO4- at higher annealing temperature (1000 °C). In addition, the carbonaceous ADSBC can promote the catalytic activity of iron oxides by synergistically facilitating the adsorption of reactants and charge transfer through COFe bonds at the interfaces. This study enables the first insights into the properties and catalytic performance of Fe-ADSBC, meanwhile unveils the mechanism, reaction pathways, and environmental impacts of the ultimate transformation products (TPs) from SMT degradation in the Fe-ADSBC/PDS system. The study also contributes to developing value-added green biochar catalysts from bio-wastes towards environmental purification.

Highly efficient adsorption of dyes by biochar derived from pigments-extracted macroalgae pyrolyzed at different temperature.

Biochar is known to efficiently adsorb dyes from wastewater. In this study, biochar was derived from macroalgae residue by pyrolysis, and the influence of varying temperature (from 400 °C to 800 °C) on biochar characteristics was investigated. Among the biochar samples tested, macroalgae-derived biochar possessing highly porous structure, special surface chemical behavior and high thermal stability was found to be efficient in removing malachite green, crystal violet and Congo red. The biochar derived by pyrolysis at 800 °C showed the highest adsorption capacity for malachite green (5306.2 mg g-1). In this study, the transformation of microalgae residue into a highly efficient dye adsorbent is a promising procedure for economic and environmental protection.

Waste biorefineries - integrating anaerobic digestion and microalgae cultivation for bioenergy production.

Commercialization of microalgal cultivation has been well realized in recent decades with the use of effective strains that can yield the target products, but it is still challenged by the high costs arising from mass production, harvesting, and further processing. Recently, more interest has been directed towards the utilization of waste resources, such as sludge digestate, to enhance the economic feasibility and sustainability of microalgae production. Anaerobic digestion for waste disposal and phototrophic microalgal cultivation are well-characterized technologies in both fields. However, integration of anaerobic digestion and microalgal cultivation to achieve substantial economic and environmental benefits is extremely limited, and thus deserves more attention and research effort. In particular, combining these two makes possible an ideal 'waste biorefinery' model, as the C/N/P content in the anaerobic digestate can be used to produce microalgal biomass that serves as feedstock for biofuels, while biogas upgrading can simultaneously be performed by phototrophic CO2 fixation during microalgal growth. This review is thus aimed at elucidating recent advances as well as challenges and future directions with regard to waste biorefineries associated with the integration of anaerobic waste treatment and microalgal cultivation for bioenergy production.

Lead removal by a magnetic biochar derived from persulfate-ZVI treated sludge together with one-pot pyrolysis.

In this study, a novel method to treat the persulfate-ZVI dewatered WAS by producing a magnetic biochar as an environmentally friendly biosorbent (nZVI-WSBC) to remove heavy metals (HMs) from wastewaters was proposed. The nZVI-WSBC exhibited good adsorption property of Pb2+ and the adsorption isotherm data were fitted well to Langmuir isotherm. Corresponding reaction kinetics fitted well with the pseudo second-order adsorption model. Notably, nZVI-WSBC was successfully used for efficient removal of HMs from real. This study comprehensively demonstrates the mechanisms between Pb2+ and nZVI-WSBC surfaces, providing a breakthrough in making a sustainable biosorbent from the dewatered iron-containing WAS.

High-efficiency removal of lead from wastewater by biochar derived from anaerobic digestion sludge.

The properties of biochar derived from waste activated sludge and anaerobic digestion sludge under pyrolysis temperature varying from 400°C to 800°C were investigated. The heavy metals adsorption efficiency of the sludge-derived biochar was also examined. Among the biochar samples tested, ADSBC600 possessing highly porous structure, special surface chemical behaviors and high thermal stability was found to remove Pb2+ from aqueous solutions efficiently with an adsorption capacity of 51.20mg/g. The Pb2+ adsorption kinetics and isotherm for ADSBC600 can be described using the pseudo second-order model and Langmuir isotherm, respectively. Analysis of the characteristics of biochar before and after metal treatment suggests that electrostatic attraction, precipitation, surface complexation and ion exchange are the possible Pb2+ removal mechanisms. This study demonstrates a successful example of waste refinery by converting anaerobic digestion sludge to feasible heavy metal adsorbents to implement the concept of circular economy.

Feasibility of CO2 mitigation and carbohydrate production by microalga Scenedesmus obliquus CNW-N used for bioethanol fermentation under outdoor conditions: effects of seasonal changes.

BACKGROUND: Although outdoor cultivation systems have been widely used for mass production of microalgae at a relatively low cost, there are still limited efforts on outdoor cultivation of carbohydrate-rich microalgae that were further used as feedstock for fermentative bioethanol production. In particular, the effects of seasonal changes on cell growth, CO2 fixation, and carbohydrate production of the microalgae have not been well investigated. RESULTS: This work demonstrates the feasibility of using outdoor tubular photobioreactors (PBR) for whole-year-round cultivation of a carbohydrate-rich microalga Scenedesmus obliquus CNW-N in southern Taiwan. Time-course profile of the carbohydrate content under nitrogen-deficient conditions was monitored to assess the seasonal changes. The optimal CO2 fixation rate and carbohydrate productivity were 430.2 mg L-1 d-1and 111.8 mg L-1d-1, respectively, which were obtained during the summer time. Under nitrogen starvation, the microalgal biomass can accumulate nearly 45-50% of carbohydrates, mainly composed of glucose that accounted for 70-80% of the total carbohydrates in the microalgal cells. This glucose-rich microalgal biomass is apparently a very suitable carbon source for bioethanol fermentation. CONCLUSION: This work shows the feasibility of combining CO2 fixation and bioethanol production using microalgae grown in outdoor photobioreactors as feedstock. The understanding of the seasonal changes in the carbohydrate productivity makes this approach more practically viable. The novel strategy proposed in this study could be a promising alternative to the existing technology dealing with CO2 mitigation and biofuels production.

Economical evaluation of sludge reduction and characterization of effluent organic matter in an alternating aeration activated sludge system combining ozone/ultrasound pretreatment.

An ozone/ultrasound lysis-cryptic growth technology combining a continuous flow anaerobic-anoxic-microaerobic-aerobic (AAMA+O3/US) system was investigated. Techno-economic evaluation and sludge lyses return ratio (r) optimization of this AAMA+O3/US system were systematically and comprehensively discussed. Economic assessment demonstrated that this AAMA+O3/US system with r of 30% (AAMA+O3/US2# system) was more economically feasible that can give a 14.04% saving of costs. In addition to economic benefits, a 55.08% reduction in sludge production, and respective 21.17% and 5.45% increases in TN and TP removal efficiencies were observed in this AAMA+O3/US2# system. Considering the process performances and economic benefits, r of 30% in AAMA+O3/US2# system was recommended. Excitation-emission matrix and Fourier transform infrared spectra analyses also proved that less refractory soluble microbial products were generated from AAMA+O3/US2# system. Improvement in 2,3,5-triphenyltetrazolium chloride electron transport system (TTC-ETS) activity in AAMA+O3/US2# further indicated that a lower sludge lyses return ratio stimulated the microbial activity.