The objective of this study was the experimental evaluation of ozonation as an additional treatment step for the removal emerging contaminants from secondary effluents of two wastewater treatment plants (WWTPs), one receiving a primarily domestic wastewater (WWTP-A), and the other one domestic sewage together with pretreated tannery wastewater streams (WWTP-B). The experimental runs were conducted at two different pH values (i.e., original pH and adjusted pH of 10) and at six different ozone doses ranging between 0.2 and 1.5 mg O₃/mg DOC. A total of 20 compounds, including 12 micropollutants (MPs) and 8 metabolites, were selected as the target analytes for the evaluation of ozonation performance. When the tested MPs and metabolites were considered individually, the maximum elimination level for each compound was reached at different doses; therefore, optimum ozone doses were determined based on the reduction of the total MP content. Ozonation at the original pH with an ozone dose in the range of 0.4–0.6 and 0.8–1.0 mg O₃/mg DOC was selected as the optimum operating condition for WWTP-A and WWTP-B, respectively, both resulting in an average overall removal efficiency of 55%. Ozone treatment yielded only poor elimination for o-desmethyl naproxen (15%), which was found to be by far the main contributor accounting alone for approximately 30% of the total MP concentration in the secondary effluents. The systematic approach used in this study could well be adopted as a guide to other domestic and municipal WWTPs, which are thought to have a highly variable composition in terms of the MPs and metabolites.

Many cities are facing various environmental problems, where performance-based planning and nature-based solutions have been proposed to address such problems. As a natural landscape in the city, urban waterfront space has efficient ecological benefits, high-quality landscape vision and environment, and it is an important carrier of citizens’ activities. However, existing studies have mainly focused on coping with environmental problems, while social functions and strategies have been neglected. Therefore, this study aims to fill such research gaps by understanding the social performance of urban waterfront spaces. Field observation and questionnaire survey were conducted in a famous urban waterfront space, Qiantang riverside walkway, in Hangzhou, China. The results indicate that the Qiantang riverside walkway serves as a space for tourism, leisure and entertainment, as the visitors who lived more than 5 km away from here accounted for about 50% and the local people also accounted for about 50%. People’s activities exhibited significantly temporal differences, where the occupation of the Qiantang riverside walkway reached a peak at night. For the people who lived far from here, they mainly depended on self-driving, which led to two critical problems relevant to transport linkage with the city and parking lot. Results also indicate that the landscape, supporting facilities and road functions could perform well among the mind of 102 respondents. However, public service and main facilities should be improved to meet more people’s requirements. Moreover, importantly, the results indicate the phenomenon of stratification and agglomeration so that the similar aspects (e.g. rest seat quantity, rest seat style) could be merged into the same cluster (e.g. rest seat) for consideration in the urban waterfront space planning and design. This study also generates some implications for the renovation of urban waterfront spaces. Overall, this study provides people with basic understanding of the social performance of existing urban waterfront spaces, which can further promote urban planners and designers to comprehensively build sustainable, resilient and healthy water-based living environments.

Recently, nanoparticles as adsorbents have received great attention due to their notable properties. In this regard, the acrylic acid adsorption from aqueous medium was examined by utilizing copper oxide (CuO) nanoparticles. In this research, initially, CuO nanoparticles were synthesized using a simple precipitation technique. CuO nanoparticles were characterized by Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM) analyzes. CuO nanoparticles synthesized were in nano scale size ranged between 140 and 180 nm. FTIR analysis also confirmed the functional groups of CuO nanoparticles. Lastly, the effects of contact time (30–240 min), concentration of acrylic acid (2–10% w/w), temperature (25–55 °C), and CuO nanoparticle dosage (0.05–0.25 g) on the adsorption of acrylic acid with CuO nanoparticles were examined. The optimum adsorption conditions were obtained as the contact time of 180 min, the concentration of acrylic acid of 10% (w/w), nanoparticle dosage of 0.05 g, and temperature of 25 °C. At these conditions, the maximum adsorption capacity of CuO nanoparticles for acrylic acid was found as 202.67 mg g⁻¹. This result confirmed that the synthesized CuO nanoparticles exhibited good adsorption performance towards to acrylic acid.

Sewage effluent has been identified as a potential source of metal(loid) contamination in the aquatic environment. The Sydney rock oyster, Saccostrea glomerata, can accumulate most metals and is well established as a biomonitor of metals in the marine environment. To determine if Burwood Beach wastewater treatment works (WWTW) is a source of metal(loid) contamination, S. glomerata was deployed for 6 weeks in effluent receiving waters (Burwood Beach near and Burwood Beach far) and at reference locations (Redhead, Fingal Island 1 and Fingal Island 2) at depths 4, 8 and 12 m. In dried oyster tissue, inductively coupled plasma mass spectrometry (ICPMS) was employed to measure concentrations of a suite of metal(loid)s including aluminium, arsenic, cadmium, copper, lead, iron, manganese, mercury, nickel, selenium, silver and zinc. It was found that for all metal(loid)s, S. glomerata tissue concentrations were not significantly higher at Burwood Beach locations in comparison to all reference locations. Concentrations of metal(loid)s were similar to those which have been detected in previous studies of background locations in New South Wales (NSW). Further, all metals fell below National Food Authority maximum residue levels (MRLs), except for arsenic and this does not appear uncommon for concentrations in biota within NSW. Comparisons to historical data suggested that concentrations of metal(loid)s in sewage effluent from Burwood Beach WWTW, assessed via concentrations in oyster tissue, are similar or lower, suggesting that changes in treatment processes initiated in the intervening time have lowered metallic inputs.

In order to investigate arsenic migration and transformation behavior under the action of microorganisms in Shimen long-term arsenic-contaminated soil under the condition of avoiding any influence of complicated soil environmental factors except increasing soil arsenic pollution degree, exogenous arsenic(III) or arsenic(V) stress experiments were carried out under the same experimental condition using the same soil sample. The changes of microbial community with exogenous arsenic concentrations and stress time were regularly monitored and comparatively analyzed. The soil microbial community shows extremely high diversities, and arsenic pollution degree affects microbial community composition rather than microbial diversity due to the long-term adaptation of microorganism to the arsenic-contaminated soil. Acidiobacteria and Nitrospirae play a key role in soil arsenic migration and transformation. Nitrospirae through producing NO₃⁻ takes part in the oxidation of As(III), and Acidiobacteria oxidizing sulfide minerals, as well as the adsorption and deposition of As(V), can enhance the soil acidity to promote soil arsenic migration and transformation, which can bring about the significant change of soil microbial community composition. Finally, its microbial community should tend to maintain a new pseudo-dynamic balance after a long time and a long-term arsenic-contaminated soil must be an arsenic oxidation-state soil. This work helps us understand why total arsenic, total organic carbon(TOC), NO₃⁻, and pH are the key environmental factors that indirectly control the mobilization and release of arsenic via influencing the structures of the microbial communities in Shimen arsenic-contaminated soil.

The goal of the present paper was to elucidate if—and how—the parameters of the Brouers–Sotolongo fractal (BSf) (n,α) kinetic model (α and τC) on the one hand, and of the generalised Brouers–Sotolongo (GBS) isotherm model (a and b) on the other hand, are correlated with adsorption pH and temperature. For that purpose, adsorption of aqueous solutions of two common dyes, methylene blue (MB) and methyl orange (MO) was carried out on four activated carbons (ACs) at three temperatures (25, 35 and 50 °C) and three pH (2.5, 5 and 8). Adsorption kinetics and isotherms were measured, and the corresponding curves were best fitted with specific forms of the aforementioned models, and corresponding to equations known as BSf (1,α) kinetic and Brouers–Gaspard isotherm models. Correlations between all model parameters and adsorption conditions were found, bringing some information about the adsorbate–adsorbent interaction.

The increasing number of applications of nanoparticles (NPs) in various fields has led to negative effects on the environment. In this study, the effects of CuO nanoparticles (CuO NPs) on Arabidopsis root tips were investigated. Significant growth inhibition on Arabidopsis roots was observed after treatment with both CuO NPs (10 mg/L) and the correspondingly released Cu²⁺ (0.80 mg/L). Scanning electron microscope images demonstrated that NPs primarily deposited on the surface of root tips and penetrated intercellular spaces after CuO NP exposure. Light and fluorescence microscope visualization revealed that the root tips were damaged severely after CuO NP exposure, with swelling of the hair zone, splitting of the cell wall junction, and disordered cell arrangement in the root tip. Semiquantitative analysis by Fourier transform infrared spectroscopy demonstrated that the cell wall xyloglucan and esterified pectin contents in the roots were decreased. Similar but weaker effects on the roots were detected after Cu²⁺ treatment. Additionally, some genes related to cell wall organization were downregulated by CuO NP stress, partially contributing to the cell wall component change. The results demonstrated that CuO NPs produced phytotoxicity to the cell wall through both physical damage and biochemical disruption, causing loosening of the tethers between cellulose microfibrils in the cell wall and the disruption of cell adhesion. The phytotoxicity of CuO NPs in the plant cell wall was mainly caused by NPs and was partially related to the released Cu²⁺. These findings are helpful to understand better the negative effects of CuO NPs on plant regarding the cell wall.

Mercury contamination and its rate of transformation and transport are increasing in the environment due to climatic variations. The mercury contamination is also rising in the polar ecosystems too. The present study assessed the content of mercury and other metals in the surface soils of tundra ecosystem of Ny-Ålesund, Svalbard. The samples were taken during summer months of 2015–2018 as part of Indian Arctic expedition. Mercury content in the surface soils were ranged from 0.01 to 0.14 μg/g and is comparable with the earlier studies carried out in the circumpolar regions. Total mercury content in plant samples was also comparable and the mean concentration was 83.45 ng/g. The mercury content is significantly varied from site to site; however, no significant variation was found between years. The interrelationship shown by mercury and other metals indicated a common contaminant pathway. The results indicated that the metals might have influenced by the local variations in the environment especially the increased thawing of permafrost as it led to more runoff of accumulated as well as atmospherically deposited metals. Hence, more detailed studies are required to understand the effect of thawing and atmospheric conditions on the cycling of metals in the polar environment.

The efficiency of xylano-pectinolytic enzymes, co-produced by a single microbial strain Bacillus pumilus, was analysed for the recycling of mixed office waste paper through deinking and compared with the alkaline chemical deinking method. Enzymes showed maximum deinking at pH 8.5, pulp consistency of 10%, xylanase-pectinase dose of 12 and 4 IU per gram pulp, respectively, after 120 min of deinking period, and temperature at 50 °C. A chemi-enzymatic approach was employed with xylano-pectinolytic enzymes and various concentrations of deinking chemicals, which showed that enzyme-treated mixed office waste pulp requires only 40% chemicals for deinking, in order to get the almost same level of various handsheets properties, as obtained by the chemical method with 100% chemicals. Similarly, the effluent load of BOD and COD contents was also decreased by 17.90 and 19.75%. This combinational approach of deinking significantly improved the various properties of the handsheets and resulted in gain of 7.5, 9.38, 6.33 and 11.65% in tear factor, burst factor, breaking length and viscosity of the handsheets, while the effective residual ink concentration analysis of deinked handsheets of mixed office waste paper showed deinking efficiency of 22.45%, which revealed the removal of ink particles during enzymatic deinking steps.

The reuse of olive mill wastewater (OMW) by spreading on agricultural land is subject to a long-time debate since they supply to agricultural land both substances of undoubted positive influence on fertility and compounds that may adversely alter its chemical, physical and microbiological characteristics and/or cause negative effects on crops. In this study different amounts of OMW from 3-phases centrifugal decanter were spread in February on soil cultivated with grapevine in a research-farm located in central Italy for 11 consecutive years, with the aim to verify the long term effect on grape production, physico-chemical and microbiological characteristics of soil. In particular, the effect of the OMW spread in the largest amount (50 L m⁻²) was an increase of the weight of the grape-brunches and total grapes production and, in addition, an improvement of the soil characteristics due to the increase of the content of the organic reducing substances with humic-like properties. Moreover, it was also ascertained that in the short-medium period (2–8 months) the respiratory activity of the micro-organisms of the soil parcels, treated with different amount of OMW, was higher than that of the soil control parcels. The results obtained demonstrated that the controlled spreading of OMW helps to increase both the grapes crop and the fertility of the soil, recycling the organic matter and mineral nutrients, in this way allowing to reduce, or avoid, the use of chemical fertilisers.