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Co-culture of microalgae-activated sludge has the potential to purify wastewater while reduce energy demand from aeration. In this work, a mechanically stirred membrane photobioreactor (stirred-MPBR) was used to evaluate the impact of the biomass retention time (BRT) on the treatment performance and membrane fouling. Results showed that stirred-MPBR was affected by BRT during treating domestic wastewater at a flux of 16.5 L m

This study aims to investigate the distribution and ecological risk assessment of microplastics (MPs) in peatland areas located in Long An province, Vietnam's Mekong Delta. In general, polyvinyl chloride (60.7%), polyethylene (25.8%), and polypropylene (11.9%) were the most abundant polymers determined in the thirty sediment samples. The hazard index (HI) remarked a level of III for MPs contamination in Tan Thanh and Thanh Hoa districts. The pollution load index (PLI) and potential ecological risk index (RI) indicated that the contamination risk of MPs polymer types in the studied sites is relatively high. According to PLI values, MPs levels of peatlands in Tan Thanh and Thanh Hoa are high and moderate, respectively, while the peatland sediments in Duc Hue district are less contaminated. Furthermore, ecological risk indexes in the peatland areas were relatively high, with PLI

This article provides an overview of heavy metal contamination in rivers and assessment methods of their contamination and effects. According to literature, rivers with heavy metal contamination in surface water are mainly found in developing countries in Asia, Africa, and Latin America and the Caribbean area, while rivers with heavy metal contamination in sediments are mostly found in Europe. The increase in heavy metal contamination in rivers has led to the adoption of individual and synergistic assessment methods. Individual methods are useful in assessing the contamination and effects for a single heavy metal, while synergistic methods assess the combined contamination and effects of several heavy metals present in surface water and sediments. These two approaches have been commonly used together in recent studies to overcome the limitations of each other and provide a more comprehensive assessment. The developments, equations, advantages, limitations, and future perspectives of these methods are discussed in this review. Calculating indexes are simple, easy-to-implement, and effective methods to provide early alerts for the environmental changes and the adverse impacts on ecosystems and human health. However, calculating indexes still have limitations due to the lack of background concentrations of heavy metals in the study area. Therefore, this issue should be addressed to overcome the limitations of these methods in the future. This review provides a useful reference for future studies on heavy metal contamination in global rivers and the assessment methods for heavy metal contamination and effects.

Emerging contaminant microplastics (MPs) are getting worldwide attention for their ubiquitous occurrence and potential risk to the environment. However, the seasonal influence on freshwater MP pollution remains poorly understood. To better understand and evaluate the riverine MPs in different seasons, this study conducted the risk assessment of MPs in an urban river, Houjin River, during the different seasons. The present study found that the MPs (0.1-5 mm, mostly 0.1-2 mm) were more abundant in the dry season (183.33 ± 128.95 items/m

Despite the known high toxicity of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, or dioxins), there are few case studies of PCDD/Fs contamination in sediment and there remains much to learn regarding their ecological impact. In this study, we performed an environmental risk assessment of a brine water storage pond near a chemical plant with high PCDD/Fs pollution potential before and after corrective actions. We found PCDD/F accumulation in the pond's fish and crab from the brine water storage pond, and the PCDD/Fs concentrations in biota higher than Taiwan's food safety standard (3.5 pg-TEQ/g). Furthermore, we found a high degree of pollution using different indices, including contamination factor (CF), modified degree of contamination (mCd), and pollution index (PI), in the pond's sediment. Before corrective actions, we also found high risk in the PCDD/F contamination in the sediment using various biological risk indices, including potential ecological risk index (RI) and risk quotient (RQ). After the corrective actions, including institutional/engineering control and remediation, the CF, mCd, and PI had decreased by 20-41 % and RI and RQ by 41-56 %. In addition, despite the slight reduction of pollution and risk index values in the whole pond, significant reduction was observed in the sediment of highly polluted area A owing to the lower disturbing suction dredging. In conclusion, the corrective actions used in this study helped decrease the pollution and ecological risk associated with this site's PCDD/Fs polluted sediment to some extent, suggesting that contamination and risk could be reduced to acceptable levels if these corrective actions are continued.

This study investigates distribution, pollution indices, and potential risk assessment for human health and ecology of eight heavy metals in twenty-five street dust samples collected from metropolitan area—Ho Chi Minh City, Vietnam. Results showed that Zn was of the highest concentration (466.4 ± 236.5 mg/kg), followed by Mn (393.9 ± 93.2 mg/kg), Cu (153.7 ± 64.7 mg/kg), Cr (102.4 ± 50.5 mg/kg), Pb (49.6 ± 21.4 mg/kg), Ni (36.2 ± 15.4 mg/kg), Co (7.9 ± 1.9 mg/kg), and Cd (0.5 ± 0.5 mg/kg). The principal component analysis revealed that three sources of heavy metals measured in street dust include vehicular activities (32.38%), mixed source of vehicular and residential activities (26.72%), and mixture of industrial and natural sources (20.23%). The geo-accumulation index values showed levels of non-pollution to moderately pollution for Mn and Co; moderately pollution for Ni; moderately to strongly pollution for Cd, Cr, and Pb; and strongly pollution for Cu and Zn. The potential ecological risk values of all sampling sites were close to the high-risk category. Zn (28.9%), Cu (25.4%), and Mn (24.4%) dominantly contributed to the ecological risk. For non-carcinogenic risk, the hazard quotient values for both children and adults were within a safety level. For carcinogenic risk, the TCRChildren was about 3 times higher than TCRAdults, but still within a tolerable limit (1 × 10−6 to 1 × 10−4) of cancer risk. Cr was a major contribution to potential risks in humans. Such studies on heavy metal in street dust are crucial but are still limited in Vietnam/or metropolitan area in Southeast Asia. Therefore, this study can fill the information gap about heavy metal contaminated street dust in a metropolitan area of Vietnam.

This study investigated the spatiotemporal variation, chemical characteristics, and source resolution of PM

Di-(2-ethylhexyl) phthalate (DEHP), a plasticizer derived from phthalate ester, is used as an additive in industrial products such as plastics, paints, and medical devices. However, DEHP is known as an endocrine-disrupting chemical, causing cancers and adverse effects on human health. This study evaluated DEHP biodegradation efficiency via food waste composting during 35 days of incubation. At high DEHP concentrations (2167 mg kg

This study investigated the spatiotemporal variation and source characteristics of volatile organic compounds (VOCs) in Kaohsiung Harbor, one of the busiest ports in the world. The VOCs' potential to form ozone (O

One of the most industrially affected rivers in Taiwan, the Houjing River, was studied in this research. The water and sediment samples were collected at five locations to measure the concentration of eight metals (As, Cd, Cr, Cu, Hg, Pb, Ni, and Zn). In order to assess the heavy metal contamination and its adverse biological effect, the heavy metal pollution index (HPI), the degree of contamination index (DC), the contamination factor (CF), the index of geo-accumulation (Igeo), and hazard quotients (HQs) were employed. The results showed that the Houjing River’s water and sediment were contaminated with heavy metals. The annually averaged values of HPI (128.3) and DC (21.3) indicate that the water is unsafe for potable use and the sediment contamination level is at considerable degree of contamination. CF and Igeo calculation show that Zn, Cu, and Cd are the three main metals contributing to heavy metal contamination in sediment. Evaluation of adverse biological effects suggests that Zn, Cu, and Ni are the major metals that cause adverse effects on organisms. This study provides an overview of the synergistic heavy metal contamination degree of the Houjing River and its adverse biological effects, which should be a reliable reference for future contamination control and management plans.

Composting is very robust and efficient for the biodegradation of organic waste; however secondary pollutants, namely greenhouse gases (GHGs) and odorous emissions, are environmental concerns during this process. Biochar addition to compost has attracted the interest of scientists with a lot of publication in recent years because it has addressed this matter and enhanced the quality of compost mixture. This review aims to evaluate the role of biochar during organic waste composting and identify the gaps of knowledge in this field. Moreover, the research direction to fill knowledge gaps was proposed and highlighted. Results demonstrated the commonly referenced conditions during composting mixed biochar should be reached such as pH (6.5-7.5), moisture (50-60%), initial C/N ratio (20-25:1), biochar doses (1-20% w/w), improved oxygen content availability, enhanced the performance and humification, accelerating organic matter decomposition through faster microbial growth. Biochar significantly decreased GHGs and odorous emissions by adding a 5-10% dosage range due to its larger surface area and porosity. On the other hand, with high exchange capacity and interaction with organic matters, biochar enhanced the composting performance humification (e.g., formation humic and fulvic acid). Biochar could extend the thermophilic phase of composting, reduce the pH value, NH

This review investigates the findings of the most up-to-date literature on bioremediation via composting technology. Studies on bioremediation via composting began during the 1990s and have exponentially increased over the years. A total of 655 articles have been published since then, with 40% published in the last six years. The robustness, low cost, and easy operation of composting technology make it an attractive bioremediation strategy for organic contaminants prevalent in soils and sediment. Successful pilot-and large-scale bioremediation of organic contaminants, e.g., total petroleum hydrocarbons, plasticizers, and persistent organic pollutants (POPs) by composting, has been documented in the literature. For example, composting could remediate >90% diesel with concentrations as high as 26,315 mg kg−a of initial composting material after 24 days. Composting has unique advantages over traditional single- and multi-strain bioaugmentation approaches, including a diverse microbial community, ease of operation, and the ability to handle higher concentrations. Bioremediation via composting depends on the diverse microbial community; thus, key parameters, including nutrients (C/N ratio = 25–30), moisture (55–65%), and oxygen content (O2 > 10%) should be optimized for successful bioremediation. This review will provide bioremediation and composting researchers with the most recent finding in the field and stimulate new research ideas.

The odor emission such as ammonia (NH

In recent years, the adoption of sustainable alternatives has become a powerful tool for replacing petroleum-based polymers. As a biodegradable alternative to petroleum-derived plastics, bioplastics are becoming more and more prevalent and have the potential to make a significant contribution to reducing plastic pollution in the environment. Meanwhile, their biodegradation is highly dependent on their environment. The leakage of bioplastics into the environment and their long degradation time frame during waste management processes are becoming major concerns that need further investigation. This review highlights the extent and rate of the biodegradation of bioplastic in composting, soil, and aquatic environments, and examines the biological and environmental factors involved in the process. Furthermore, the review highlights the need for further research on the long-term fate of bioplastics in natural and industrial environments. The roles played by enzymes as biocatalysts and metal compounds as catalysts through composting can help to achieve a sustainable approach to the biodegradation of biopolymers. The knowledge gained in this study will also contribute to the development of policies and assessments for bioplastic waste, as well as provide direction for future bioplastics research and development.

In this study, the Bragg resonance of water waves scattered by multiple permeable thin barriers over a series of periodic breakwaters was solved by employing the eigenfunction matching method (EMM). The geometrical configuration was divided into multiple shelves separated by steps, on which thin permeable barriers were implemented. The solution was approximated using eigenfunctions with unknown coefficients that were considered as the amplitudes of the water waves for each shelf. The conservations of mass and momentum were then applied to form a system of linear equations, which was sequentially solved by a sparse-matrix solver. The proposed method degenerates to traditional EMM formulations if thin barriers, the permeability of the barrier, or bottom undulations are not considered. The validity of the suggested method was examined based on the results in the literature. Bragg resonances by bottom-standing, surface-piecing, and fully submerged permeable barriers over a series of periodic trapezoidal or half-cosine breakwaters were studied. In addition, the breakwater amplitudes, permeable parameters of the barriers, and incident angles of water wave scattering by different types of periodic breakwaters were discussed.

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.

Microplastic pollution is becoming a global challenge due to its long-term accumulation in the environment, causing adverse effects on human health and the ecosystem. Sludge discharged from wastewater treatment plants (WWTPs) plays a critical role as a carrier and primary source of environmental microplastic contamination. A significantly average microplastic variation between 1000 and 301,400 particles kg

Refined cobia liver oil is a nutritional supplement (CBLO) that is rich in polyunsaturated fatty acids (PUFAs), such as DHA and EPA, however, PUFAs are prone to oxidation. In this study, the fabrication of chitosan-TPP-encapsulated CBLO nanoparticles (CS@CBLO NPs) was achieved by a two-step method, including emulsification and the ionic gelation of chitosan with sodium tripolyphosphate (TPP). The obtained nanoparticles were inspected by dynamic light scattering (DLS) and showed a positively charged surface with a z-average diameter of between 174 and 456 nm. Thermogravimetric analysis (TGA) results showed the three-stage weight loss trends contributing to the water evaporation, chitosan decomposition, and CBLO decomposition. The loading capacity (LC) and encapsulation efficiency (EE) of the CBLO loading in CS@CBLO NPs were 17.77–33.43% and 25.93–50.27%, respectively. The successful encapsulation of CBLO in CS@CBLO NPs was also confirmed by the Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. The oxidative stability of CBLO and CS@CBLO NPs was monitored by FTIR. As compared to CBLO, CS@CBLO NPs showed less oxidation with a lower generation of hydroperoxides and secondary oxidation products after four weeks of storage. CS@CBLO NPs are composed of two ingredients that are beneficial for health, chitosan and fish oil in a nano powdered fish oil form, with an excellent oxidative stability that will enhance its usage in the functional food and pharmaceutical industries.