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Emerging contaminants (ECs) are increasingly recognized as threats to human health and ecosystems. This review evaluates advanced analytical methods, particularly mass spectrometry, for detecting ECs and understanding their toxicity, transformation pathways, and environmental distribution. Our findings underscore the reliability of current techniques and the potential of upcoming methods. The adverse effects of ECs on aquatic life necessitate both in vitro and in vivo toxicity assessments. Evaluating the distribution and degradation of ECs reveals that they undergo physical, chemical, and biological transformations. Remediation strategies such as advanced oxidation, adsorption, and membrane bioreactors effectively treat EC-contaminated waters, with combinations of these techniques showing the highest efficacy. To minimize the impact of ECs, a proactive approach involving monitoring, regulations, and public education is vital. Future research should prioritize the refining of detection methods and formulation of robust policies for EC management.

Pesticide pollution has been posing a significant risk to human and ecosystems, and photocatalysis is widely applied for the degradation of pesticides. Machine learning (ML) emerges as a powerful method for modeling complex water treatment processes. For the first time, this study developed novel ML models that improved the estimation of the photocatalytic degradation of various pesticides using ZnO-based photocatalysts. The input parameters encompassed the source of light, mass proportion of dopants to Zn, initial pesticide concentration (C0), pH of the solution, and irradiation time. Notably, the numerical data were extracted from the literature via relevant tables (directly) or graphs (indirectly) using the web-based tool WebPlotDigitizer. Additionally, physicochemical properties such as the molecular weight of the dopants and pesticides, as well as the water solubility of both dopants and pesticides, were considered. Four ML models including multi-layer perceptron artificial neural network (MLP-ANN), particle swarm optimization-adaptive neuro fuzzy inference system (PSO-ANFIS), radial basis function (RBF), and coupled simulated annealing-least squares support vector machine (CSA-LSSVM) were developed. In comparison, RBF showed the best accuracy of modeling among all models, with the highest determination coefficient (R2) of 0.978 and average absolute relative deviation (AARD) of 4.80%. RBF model was effective in estimating the photocatalytic degradation of pesticides except for 2-chlorophenol, triclopyr and lambda-cyhalothrin, where CSA-LSSVM model demonstrated superior performance. Dichlorvos was completely degraded by ZnO photocatalyst under visible light. The sensitivity analysis by relevancy factor exhibited that light irradiation time and initial pesticide concentration were the most important parameters influencing photocatalytic degradation of pesticides positively and negatively, respectively. The new ML models provide a powerful tool for predicting pest

Perfluorooctanoic acid (PFOA) is a highly persistent organic pollutant of global concern. A novel nanocomposite composed of ZnO nanoparticles and citric acid-modified g-C3N4 was synthesized by ball milling process. The synthesized nanocomposite was more efficient than pure ball-milled ZnO nanoparticles for PFOA elimination under visible light irradiation. The optimal hybrid photocatalyst, produced by the addition of 5 wt% of citric acid-modified g-C3N4, demonstrated significantly better performance for PFOA removal than pure ZnO nanoparticles under UV irradiation, with the apparent rate constants of 0.468 h−1 and 0.097 h−1, respectively. The addition of peroxymonosulfate (0.53 g L−1) significantly increased PFOA removal, clarifying the crucial effect of sulfate radicals on PFOA photodegradation. In comparison, citric acid-modified g-C3N4 was not effective for PFOA elimination under visible light irradiation, even with the addition of peroxymonosulfate. Further experiments under dark conditions identified surface adsorption on hybrid photocatalyst as a key process in total PFOA removal. In summary, PFOA removal by ZnO@citric acid-modified graphitic carbon nitride nanocomposites is due to the combined action from adsorption and photodegradation, with adsorption as the dominating mechanism.

Pharmaceuticals are widely used and often discharged without metabolism into the aquatic systems. The photocatalytic degradation of pharmaceutical compounds propranolol, mebeverine, and carbamazepine was studied using different titanium dioxide nanostructures suspended in water under UV and UV-visible irradiation. Among three different photocatalysts, the degradation was most effective by using Degussa P25 TiO2, followed by Hombikat UV100 and Aldrich TiO2. The photocatalytic performance was dependent on photocatalyst dosage, with an optimum concentration of 150 mg L-1. The natural aquatic colloids were shown to enhance the extent of photocatalysis, and the effect was correlated with their aromatic carbon content. In addition, the photocatalysis of pharmaceuticals was enhanced by the presence of nitrate, but inhibited by the presence of 2-propanol, indicating the importance of hydroxyl radicals. Under optimum conditions, the pharmaceuticals were rapidly degraded, with a half-life of 1.9 min, 2.1 min, and 3.2 min for propranolol, mebeverine, and carbamazepine, respectively. In treating sewage effluent samples, the photocatalytic rate constants for propranolol (0.28 min-1), mebeverine (0.21 min-1), and carbamazepine (0.15 min-1) were similar to those in water samples, demonstrating the potential of photocatalysis as a clean technology for the effective removal of pharmaceuticals from sewage effluent.

This work presents an innovative approach to developing a low-carbon and hazard-free cementitious material (EGC) by activating ground granulated blast-furnace slag (GGBS) with electrolytic manganese residue (EMR), which has an excellent heavy metal solidified capacity. Herein, the multi-step leaching was creatively conducted to investigate the solidified morphology of heavy metals in hazardous EMR. CO2 emission per unit strength factor was calculated to quantitatively analyze the low-carbon degree. The results show that the added hazardous EMR rich in sulfate and the dilution effect caused by the decrease in GGBS lessen the final setting time and fluidity. Low-temperature calcination (200 °C) alters the dissolution rate of ettringite and AFm-like phases by changing the sulfate crystal. Excessive acidic EMR consumes more calcium hydroxide and lowers the pH of the EGC system, resulting in weakened GGBS activity. The formation of jouravskite, thaumasite, and henritermierite are AFm-like hydrated lamellated structures, which provides evidence for the immobilization of Mn2+ in EMR. Vast Mn2+ are embedded in the main interlayer of [Ca2Al(OH)6]+ by substituting Al to form AFm-like phase. The lowest 60d unit compressive strength carbon emission of the EGC system containing 20 % calcinated EMR is 0.78 kg∙MPa-1∙m-3, meaning the substitution barrier is better addressed by adding calcined EMR. This work provides an innovative solution for high value-added and hazard-free utilization for EMR and carbon reduction in the cement industry.

Phthalic acid esters (PAEs) are known as the most widely used plasticizer as well as one of the ubiquitously distributed emerging pollutants. Biodegradation and bioremediation via application of PAEs-degrading microbes is promising. In this study, a novel marine microbe, Gordonia hongkongensis RL-LY01, was isolated from mangrove sediment showing high di-(2-ethylhexyl) phthalate (DEHP) degradation capacity. Strain RL-LY01 could degrade a wide range of PAEs and the degradation kinetics of DEHP followed the first-order decay model. Meanwhile, good environmental adaptability, preference to alkaline conditions and good tolerance to salinity and metal ions was shown. Further, metabolic pathway of DEHP in strain RL-LY01 was proposed, with di-ethyl phthalate, phthalic acid, benzoic acid and catechol as intermediates. Additionally, one known mono-alkyl phthalate hydrolase gene (mehpH) was identified. Finally, the excellent performance during bioremediation of artificial DEHP-contaminated saline soil and sediment indicated strain RL-LY01 employs great application potential for the bioremediation of PAE-contaminated environments.

Simultaneous removal of nitrogen, phosphate and emerging pollutants are critical for safe reuse of wastewater, but research in this field is limited. In the present study, a novel aerobic denitrifying phosphate-accumulating bacterial strain RL-GZ01 was found to be able to utilize phthalic acid esters (PAEs) as carbon resource for cell growth. Based on 16S rRNA gene analysis, physiological and biochemical characterization, and genome-based average nucleotide identity calculation, RL-GZ01 was identified as Rhodococcus pyridinivorans. Strain RL-GZ01 showed high DEHP degradation in alkaline conditions and good tolerance of salinity and organic solvents. The degradation of DEHP by RL-GZ01 fitted well with a modified Gompertz model (R2 = 0.9985). Metabolic intermediates of DEHP were identified via UHPLC-MS/MS analysis and the catabolic pathway was proposed thereafter. Genes and gene clusters contributed to the utilization of DEHP were analyzed through genomic analysis. Analysis of KEGG nitrogen metabolism pathway indicated that nitrate and nitrite were further transformed into ammonium which was further used for the biosynthesis of L-glutamine and L-glutamate. Strain RL-GZ01 was further identified as a denitrifying phosphate accumulating organism which can accumulate phosphate by generating polyphosphate. Finally, strain RL-GZ01 was applied to municipal wastewater treatment for simultaneous removal of nitrogen, phosphate and DEHP. The removal percentages of DEHP (5 mg/L), TN (71.2 mg/L), NH4+-N (70.9 mg/L), PO43−-P (10.89 mg/L) and COD (622.4 mg/L) by strain RL-GZ01 were 89.94 %, 64.45 %, 64.94 %, 76.30 % and 63.23 % within 84 h, respectively. These demonstrated the capability of strain RL-GZ01 for the biological treatment of wastewater containing PAEs.

As the global population reaches eight billion, large quantities of wastewater (domestic, industrial, livestock) need to be treated in an efficient, green, and environmentally friendly manner. Wastewater hydroponics technology (HP) can efficiently remove various pollutants (conventional and emerging pollutants, heavy metals, and microorganisms) and create economic benefits. This paper aims to systematically review the principles, applications, and limitations of wastewater hydroponics technology in the context of pollution and nutrient removal. Unlike constructed wetlands, wastewater hydroponics has been proven to be effective in removing pollutants through small-scale in situ restoration. For instance, the average removal of COD, total nitrogen (TN), total phosphorus (TP), copper (Cu), and zinc (Zn) was more than 70%, 60%, 80%, 64.2%, and 49.5%, respectively. However, HP technology still has the disadvantages of high energy consumption, complex control parameters, and low public acceptance of using wastewater for planting crops. Therefore, further research is needed to reduce system energy consumption. In addition, hybrid technologies, such as two-stage hydroponics that use aquatic plants (algae or aquatic floating weeds) to recycle pollutant-containing wastewater nutrients for hydroponics, should be further developed.

Mycolicibacterium phocaicum RL-HY01, a marine bacterial strain with the capability to degrade phthalic acid esters (PAEs), was isolated from Zhanjiang Bay, China. Here, the complete genome sequence of strain RL-HY01 was presented. The genome of strain RL-HY01 contains one circular chromosome of 6,064,759 bp with a G + C content of 66.93 mol%. The genome contains 5681 predicted protein-encoding genes, 57 tRNA genes, and 6 rRNA genes. Genes and gene clusters potentially involved in the metabolism of PAEs were further identified. The genome Mycolicibacterium phocaicum RL-HY01 will be helpful for advancing our understanding of the fate of PAEs in marine ecosystem.

To mitigate the shortage of freshwater resource in the island and coastal regions, using seawater (SW) for concrete mix can provide significant economic and environmental benefits. To achieve a safe and reliable application, in-depth investigation is needed on hydration of Portland cement in SW. The composition of solid and liquid phases in hydrated Portland cement was quantitively determined and analysed in this study. The use of SW not only significantly increases the hydration rate of clinker but also affects the evolution of phase assemblage. Both the thermodynamic calculations and experimental determinations indicates the formation of Friedel's salt (FS) instead of sulfo-AFm in hydrated cement by SW, implying sulfate ions cannot compete with chloride ions to combine with AFm phases. The characteristic reaction in SW leads to higher sulfate concentration, thus indirectly hindering ettringite (AFt) conversion at the late stage. Through the experimental quantification of thermogravimetric analysis and X-ray diffraction analysis, the kinetic model of clinker dissolution was modified to be more suitable for the hydration of Portland cement in SW. The calculation from coupled models exhibits a novel method to evaluate the evolution of phases in cement hydration. Through model calculations, 3.70% higher solid volume and 12.2% lower liquid volume were obtained in the cement-SW paste at the end of the hydration, which may cause the mechanical properties to be more sensitive under environmental humidity and the temperature.

Of current interest is visible-light activated g-C3N4, owing to its unique physicochemical properties for the photocatalytic H2 production and pollutant remediation. In this research, the synthetic procedures, physicochemical properties, and major approaches to overcome the intrinsic drawbacks of g-C3N4 are reviewed. Of different synthesis procedures for GCN, thermal polymerization is recommended with advantages such as simplicity, economic, and high yield. Element doping, as a facile method, can modify g-C3N4 structure and improve its performance in the photocatalytic evolution of H2 which is significantly increased from 208 µmol h−1 g−1 for bare g-C3N4 to 5128 µmol h−1 g−1 for P-doped g-C3N4. Ammonium salts can be effectively used for the synthesis of g-C3N4 nanosheets and element doping simultaneously. Vacancy defect plays an important role in the improvement of the photocatalytic activity. Compared to custom photocatalysis and electrocatalysis, photoelectrocatalysis is highly promising for pollutant decontamination due to the effective separation of charge carriers.

One of the key concerns in the 21st century, alongside the growing population, is the increase in energy consumption and the resulting global warming. The impact of CO2, a prominent greenhouse gas, has garnered significant attention in the realm of CO2 capture and gas purification. CO2 absorption can be enhanced by introducing some additives into the aqueous solution. In this study, the accuracies of some of the most up-to-date computational approaches are investigated. The employed machine learning methods are hybrid-adaptive neuro-fuzzy inference system (Hybrid-ANFIS), particle swarm optimization-adaptive neuro-fuzzy inference system (PSO-ANFIS), least-squares support vector machines (LSSVM) and genetic algorithm-radial basis function (GA-RBF). The developed models were used in estimating the solubility of CO2 in binary and ternary amines aqueous solutions. i.e. blends of monoethanolamine (MEA), triethanolamine (TEA), aminomethyl propanol (AMP), and methyldiethanolamine (MDEA). This modeling study was undertaken over relatively significant ranges of CO2 loading (mole of CO2/mole of solution) as a function of input parameters, which are 0.4–2908 kPa for pressure, 303–393.15 K for temperature, 36.22–68.89 g/mol for apparent molecular weight, and 30–55 wt % for total concentration. In this work, the validity of approaches based on different statistical graphs was investigated, and it was observed that the developed methods, especially the GA-RBF model, are highly accurate in estimating the data of interest. The obtained AARD% values for the developed models are 18.63, 8.25, 12.22, and 7.54 for Hybrid-ANFIS, PSO-ANFIS, LSSVM, and GA-RBF, respectively.

In this work, the electrolytic manganese residues (EMR) were used as sulfate activators for fly ash and granulated blast-furnace slag to fabricate highly reactive supplementary cementitious materials (SCMs). The findings promote the implementation of a win-win strategy for carbon reduction and waste resource utilisation. The effects of EMR dosing on the mechanical properties, microstructure and CO2 emission of the EMR-doped cementitious materials are investigated. The results show that low dosing EMR (5 %) produced more ettringite, fostering early strength development. The fly ash-doped mortar strength increases and then decreases with the addition of EMR from 0 to 5 % to 5-20 %. It was found that blast furnace slag contributes less to strength than fly ash. Moreover, the sulfate activation and the micro-aggregate effect compensate for the EMR-induced dilution effect. The significant increase in strength contribution factor and direct strength ratio at each age verifies the sulfate activation of EMR. The lowest EIF90 value of 5.4 kg∙MPa-1∙m3 was achieved for the fly ash-doped mortar with 5 % EMR, suggesting the synergistic effect between fly ash and EMR optimised the mechanical properties while maintaining lower CO2 emissions.

Per- and polyfluoroalkyl substances (PFAS), one of the main categories of emerging contaminants, are a family of fluorinated organic compounds of anthropogenic origin. PFAS can endanger the environment and human health because of their wide application in industries, long-term persistence, unique properties, and bioaccumulation potential. This study sought to explain the accumulation of different PFAS in water bodies. In aquatic environments, PFAS concentrations range extensively from <0.03 (groundwater; Melbourne, Australia) to 51,000 ng/L (Groundwater, Sweden). Additionally, bioaccumulation of PFAS in fish and water biota has been stated to range from 0.2 (Burbot, Lake Vättern, Sweden) to 13,900 ng/g (Bluegill samples, U.S.). Recently, studies have focused on PFAS removal from aqueous solutions; one promising technique is advanced oxidation processes (AOPs), including microwaves, ultrasound, ozonation, photocatalysis, UV, electrochemical oxidation, the Fenton process, and hydrogen peroxide-based and sulfate radical-based systems. The removal efficiency of PFAS ranges from 3% (for MW) to 100% for UV/sulfate radical as a hybrid reactor. Therefore, a hybrid reactor can be used to efficiently degrade and remove PFAS. Developing novel, efficient, cost-effective, and sustainable AOPs for PFAS degradation in water treatment systems is a critical area of research.

Anaerobic digestion (AD) was utilized to treat the ever-growing amount of organic fraction of municipal solid waste (OFMSW) generated due to population growth and the expansion of the global economy. The widespread application of AD has led to a continuous increase in residual solid digestate that necessarily requires further disposal. Improving AD efficiency and reducing the large amount of digestate is necessary. This study investigated the chemical and physical characteristics of biochar derived from digestate at different pyrolysis temperatures (300 °C, 500 °C, and 700 °C), as well as corn stover biochar at 500 °C, and their effects on AD performance. The pH value of the biochar increased with an increase in pyrolysis temperature while the electrical conductivity decreased. Macropores dominated the biochar’s pore size, and decreased with an increased pyrolysis temperature. The biochar preparation temperature significantly influenced the AD efficiency. Biochar prepared at 700 °C outperformed the other groups, improving the biogas production yields by 10.0%, effectively shortening the lag time, and increasing the average chemical oxygen demand (COD) degradation rate by 14.0%. The addition of biochar (700 °C) and corn stover biochar increased the relative abundance of the volatile fatty acid (VFAs)-oxidizing bacteria Syntrophomonadaceae, which expedited the acid conversion in AD systems. Biochar facilitated direct interspecies electron transfer between DMER64 and Trichococcus with Methanosaeta, enhancing the biogas production performance. These findings confirmed that the biochar derived from digestate promoted biogas production and acid conversion in the AD system of OFMSW. Furthermore, biochar has an improved AD stability, which represents a promising approach to recycling digestate.

Fat-soluble vitamins (FSVs) occur in various active forms, each of which exhibits the biological activity of the respective vitamin and performs the same metabolic functions within the body. The accurate determination of these compounds in food, biological, and pharmaceutical samples is significant for food labeling, treatment/diagnosis of hypo/hypervitaminosis, pharmacological research, and quality supervision of food/drug. In this review, the most recent advances in extraction and chromatographic methods to evaluate active forms of FSVs in various matrices have been discussed and compared. Owing to the recent research trends in the multiform-vitamin assay, particular attention was devoted to the newly established extraction and analytical approaches allowing the simultaneous isolation, separation, and detection of multiple FSV compounds, considering the challenges and their potential solutions. The suitability and specificity of multi-dimensional chromatography-based approaches for FSV substances have been illustrated in detail. Analytical challenges related to mass spectrometry detection of FSV substances have also been briefly discussed.

This research represented the first study of perfluorooctanoic acid (PFOA) decomposition using immobilized ZnO nanoparticles by electrophoretic deposition in photocatalysis and photoelectrocatalysis. Overall, considering process performance, application under visible light exposure, and cost-effectiveness, ZnO nanoparticles are highly promising for PFOA degradation. The effect of the probable production of sulfate radicals on PFOA photocatalytic decomposition over ZnO films was investigated by the addition of different concentrations of peroxymonosulfate (PMS). Notably, ∼42% of PFOA was decomposed within 2 hours (rate constant = 0.287 h−1) under UV irradiation in the presence of 0.27 g L−1 PMS. Importantly, the same amount of PMS initiated PFOA degradation under visible light exposure with the rate constant of 0.125 h−1. In photoelectrocatalysis, the optimal ZnO film demonstrated an excellent degradation performance of ∼49% within 2 hours at V = 0 (under UV irradiation). Overall, ZnO was highly promising in both photoelectrocatalysis and PMS-assisted photocatalysis, although PMS could enhance ZnO corrosion. In addition to the sulfate radicals, the photogenerated holes and superoxide radicals were among the main active species responsible for PFOA decomposition.

The adsorption process of inorganic arsenic (As) plays an important role in its mobility, bioavailability, and toxicity in the river environment. In this work, the adsorption of dissolved arsenite (As(III)) and arsenate (As(V)) by microplastics (MPs) pellets (polystyrene (PS) and low-density polyethylene (LDPE)), river sediment, and their mixture were investigated to assess the adsorption affinities and mechanism. The adsorption kinetics showed slow and mild rising zones from the natural behavior of the chemical adsorption. The results indicated that both MP characteristics and water properties played a significant role in the adsorption behavior of inorganic As species. The As adsorption equilibrium was modeled well by both Langmuir and Freundlich isotherms and partly fitted with the Sips model suggesting that both mono-layer and multi-layer adsorption occurred during adsorption The spontaneous adsorption process for both As(III) and As(V) was evidenced by the adsorption thermodynamics. The maximum adsorption capacities of As(III) and As(V) reached 143.3 mg/kg and 109.8 mg/kg on PS in deionized water, which were higher than those on sediment-PS mixture (119.3 mg/kg, 99.2 mg/kg), which were all lower than on sediment alone (263.3 mg/kg, 398.7 mg/kg). The Fourier transform infrared spectroscopy analysis identified that As(III) and As(V) interaction with sediment surface functional groups was the main adsorption mechanism from surface complexation and coordination. Two functional groups of polystyrene (-NH2, -OH) were mainly involved in the adsorption of inorganic As species on PS, while -COO- and -OH functional groups contributed to the adsorption mechanism of inorganic As species on LDPE. The findings provide valuable insight on the adsorption behavior and mechanisms of As(III) and As(V) in river systems in the presence of MPs particles. Both PS and LDPE were shown to be less effective than river sediment in the adsorption of As species from water, which provides a

Perfluorooctanoic acid (PFOA) is used in a variety of industries and is highly persistent in the environment, with potential human health risks. Photocatalysis has been extensively used for the decomposition of various organic pollutants, yet its simulation and modeling are challenging. This research aimed to establish different machine learning (ML) algorithms which can simulate and predict the photocatalytic degradation of PFOA. The published results were used to estimate and predict the photocatalytic degradation of PFOA. Statistical criteria including the coefficient of determination (R2), mean absolute error (MAE), and mean squared error (MSE) were considered in assessing the best method of modeling. Among the seven ML algorithms pre-screened, Adaptive Boosting (AdaBoost), Gradient Boosting Machine (GBM), and Random Forest (RF) showed the best performance and were chosen for deep modeling and analysis. Grid search was used to optimize the models developed by AdaBoost, GBM, and RF; and permutation variable importance (PVI) was used to analyze the relative importance of different variables. Based on the modeling results, GBM model (R2 = 0.878, MSE = 106.660, MAE = 6.009) and RF model (R2 = 0.867, MSE = 107.500, MAE = 6.796) showed superior performances compared with AdaBoost model (R2 = 0.574, MSE = 388.369, MAE = 16.480). Furthermore, the PVI results suggested that the GBM model provided the best outcome, with the light irradiation time, type of catalyst, dosage of catalyst, solution pH, irradiation intensity, initial PFOA concentration, oxidizing agents (peroxymonosulfate, ammonium persulfate, and sodium persulfate), irradiation wavelength, and solution temperature as the most important process variables in decreasing order.

This paper reviewed the mechanisms of biochar in relieving ammonia inhibition. Biochar affects nitrogen-rich waste's anaerobic digestion (AD) performance through four ways: promotion of direct interspecies electron transfer (DIET) and microbial growth, adsorption, pH buffering, and provision of nutrients. Biochar enhances the DIET pathway by acting as an electron carrier. The role of DIET in relieving ammonia nitrogen may be exaggerated because many related studies don't provide definite evidence. Therefore, some bioinformatics technology should be used to assist in investigating DIET. Biochar absorbs ammonia nitrogen by chemical adsorption (electrostatic attraction, ion exchange, and complexation) and physical adsorption. The absorption efficiency, mainly affected by the properties of biochar, pH and temperature of AD, can reach 50 mg g-1 on average. The biochar addition can buffer pH by reducing the concentrations of VFAs, alleviating ammonia inhibition. In addition, biochar can release trace elements and increase the bioavailability of trace elements.

Aerobic composting is widely used worldwide as a natural process for handling human waste. Such waste often contains pharmaceutical residues from human consumption, yet their impact on composting has not been studied. The aim of this study is to investigate the impact of the antihistamine cimetidine (10 mg/kg, 100 mg/kg) on the aerobic composting of human feces. The key results show that 10 mg/kg of cimetidine accelerates temperature increase and moisture removal of the composting substrate. The organic matter in all the groups gradually decreased, and the pH values increased first and then declined with the composting time, with no significant differences between the groups. The NH4+-N concentrations and NH3 emission reached the maximum at 1.5 days and then declined rapidly, while the NO2−-N concentrations increased and then decreased, and the NO3−-N contents tended to increase all the time during the composting. The 100 mg/kg cimetidine caused a higher maximal NH4+-N concentration of compost, and a lower maximal NH3 emission at 1.5 days, while 10 mg/kg cimetidine led to more NO2−-N and NO3−-N contents. In addition, 10 mg/kg cimetidine enhanced the aromatization and humification of dissolved organic matter and promoted the degradation of aliphatic substances. Furthermore, 100 mg/kg cimetidine generated a larger influence on the microorganisms than 10 mg/kg cimetidine, especially for the microorganisms related to nitrogen transformation. The findings imply that cimetidine has a dose-dependent impact on the decomposition of organic matter and the conversion of nitrogen in human feces during composting. It deserves further investigation of the possible hormesis effect.

The consumption of pharmaceuticals and personal care products (PPCPs) has been widely increasing, yet up to 90-95% of PPCPs consumed by human are excreted unmetabolized. Moreover, the most of PPCPs cannot be fully removed by wastewater treatment plants (WWTPs), which release PPCPs to natural water bodies, affecting aquatic ecosystems and potentially humans. This study sought to review the occurrence of PPCPs in natural water bodies globally, and assess the effects of important factors on the fluxes of pollutants into receiving waterways. The highest ibuprofen concentration (3738 ng/L) in tap water was reported in Nigeria, and the highest naproxen concentration (37,700 ng/L) was reported in groundwater wells in Penn State, USA. Moreover, the PPCPs have affected aquatic organisms such as fish. For instance, up to 24.4 × 103 ng/g of atenolol was detected in P. lineatus. Amongst different technologies to eliminate PPCPs, algae-based systems are environmentally friendly and effective because of the photosynthetic ability of algae to absorb CO2 and their flexibility to grow in different wastewater. Up to 99% of triclosan and less than 10% of trimethoprim were removed by Nannochloris sp., green algae. Moreover, variable concentrations of PPCPs might adversely affect the growth and production of algae. The exposure of algae to high concentrations of PPCPs can reduce the content of chlorophyll and protein due to producing reactive oxygen species (ROS), and affecting expression of some genes in chlorophyll (rbcL, psbA, psaB and psbc).

Limestone powder (LP) and sodium meta-aluminate (SMA) were used to fabricate calcium carbonate-based cementitious material, as a solution to address the solid waste problem. The effects of SMA doses and curing conditions on the hydration properties and mechanical performance of paste were investigated. The results show that the 28-day unconfined compressive strength and flexural strength of the paste with an LP/SMA ratio of 2/1 were 49.7 and 15.9 MPa, respectively. The characterization by scanning electron microscopy, X-ray diffraction, and thermal gravimetry shows that the calcium aluminum carbonate hydroxide hydrate (CACHH) was the predominant hydrated product and had a dense layered double hydroxide structure (LDHs). The microbridge effect developed by LDHs significantly increases the flexural strength of the paste. Meanwhile, the developed paste exhibited an extremely low carbon emission and energy consumption. This study also reveals the mechanism of LP incorporated with SMA to form CACHH. Overall, this work provides an approach of high value-added utilization for LP as a binder without tedious operation, which could address carbon emission reduction and circular economy of LP.

The direct stockpiling of electrolytic manganese residues (EMR) poses a major environmental issue, and more eco-friendly disposal is urgently needed. The combination of cement solidified waste (CSW) and direct electric curing (DEC) provides a potential solution for hazard-free value-added utilization of EMR. The effects of DEC voltages and EMR dosages on mechanical properties, hydrated products, pore structure of mixture were investigated. The influencing mechanism of DEC on the properties of cement hydration was explored in-depth using TG and XRD results. The environmental and economic evolution of DEC was analyzed, and the leaching test was conducted to evaluate the immobilization of heavy metals. Results indicate that cement-EMR pastes cured in higher DEC voltage and reduced EMR dosage increase mechanical strength and improve pore structure and capillary water absorption with respect to indoor curing (IC). The increased cement dosage improves the effectiveness of CSW, while the increased DEC voltage enhances the ionic driving force. The boosted ettringite formation occurs in system after introducing DEC and amplifying the DEC voltage. The improvement of ion concentration in DEC accelerates the formation of hydration products. The CO2-e per MPa (EIF) and cost per MPa (CIF) values of paste DMP-7 cured in 12V-DEC exhibit the lowest values with respect to those cured in other voltages and IC. The decrease in the leaching amount of Mn2+ and NH4+-N as the DEC voltage increases, and the 28-d leaching concentration of Mn2+ and NH4+-N in pastes are in accordance with the national standards. The application of DEC and cement-solidified disposal for EMR could provide a potential solution for high-value and large-capacity disposal of hazardous solid waste.

The application of aluminum-based flocculant in wastewater treatment results in a large amount of aluminum-rich sewage sludge. This work investigated the influence of calcination process on physicochemical characteristics and pozzolanic activity of aluminum (Al)-rich sludge ash and studied the effect of sludge ash on cement hydration. The results showed that higher calcination temperature from 600 ℃ to 900 ℃ increased the amorphous content in sludge ash. The pozzolanic activity of sludge ash calcined at 800 ℃ and 900 ℃ was confirmed by Frattini test. In view of strength activity index of blended mortar and energy conservation, the optimal calcination condition of sewage sludge ash was calcined at 800 ℃ with air-cooling. The addition of sludge ash promoted the transformation of ettringite to monosulfate phase in cement paste. However, the high Al concentration dissolved from S6 and S7 ash inhibited significantly the cement hydration and resulted in low compressive strength values of the blended mortars. The pozzolanic reaction of S8 and S9 ash produced more hydration heat and additional Al-bearing products such as katoite and monosulfate which contributed to the strength development of mortars. Furthermore, the heavy metals in sewage sludge can be immobilized in ash structure during calcination process and the structure of hydration products, which ensures the environmental security of sludge ash utilization in construction materials.

The presence of pesticides in aquatic environments has threatened marine food resources, aquaculture, fisheries and human health; therefore, two most used insecticides were removed during this study. Two photobioreactors, including biochar and Chlorella vulgaris/activated sludge (reactor 1), and Chlorella vulgaris/activated sludge (reactor 2) were run to remove chlorpyrifos (CPF) and cypermethrin (CYP). Proteobacteria, Bacteroidetes and Chloroflexi were the dominant phyla of activated sludge. The optimization performance of both reactors was conducted by response surface methods. The performance of first photobioreactor was better than that in the second reactor, achieving abatement of 88.80% CPF and 93.12% CYP, at 69.7 h contact time and 0.32 mg/L initial concentration. The toxicity of CPF and CYP to Chlorella vulgaris was monitored under 0–4 mg/L of insecticide concentrations and 0–72 h contact time. The minimum chlorophyll content (2 mg/L) and protein (16.7%), and maximum growth inhibition (89.7%) were recorded at 4 mg/L insecticides concentration and 72 h contact time. Moreover, molecular docking simulation for catalytic enzyme degradation of Proteobacteria, Bacteroidetes and microalgae was carried out using individual hydrolase enzymes: carboxypeptidase in microalgae, isochorismatase hydrolase in Proteobacteria and alpha-L-arabinofuranosidase in Bacteroidetes. Ligand-binding energy, affinity and dimensions of ligands-binding sites in the enzyme cavity were calculated in each case. Hydrolase is an enzyme group that offers a promising practical application for the degradation of CYP and CPF due to its cavity features. This analysis demonstrated the mode of interaction of ligands with hydrolase enzymes in different species.