Treatment System Research Articles

Transitional Medicine of Intractable Primary Dyslipidemias in Japan.

Transitional medicine refers to the seamless continuity of medical care for patients with childhood-onset diseases as they grow into adulthood. The transition of care must be seamless in medical treatment as the patients grow and in other medical aids such as subsidies for medical expenses in the health care system. Inappropriate transitional care, either medical or social, directly causes poorer prognosis for many early-onset diseases, including primary dyslipidemia caused by genetic abnormalities. Many primary dyslipidemias are designated as intractable diseases in the Japanese health care system for specific medical aids, as having no curative treatment and requiring enormous treatment costs for lipid management and prevention of complications. However, there are problems in transitional medicine for primary dyslipidemia in Japan. As for the medical treatment system, the diagnosis rate remains low due to the shortage of specialists, their insufficient link with generalists and other field specialists, and poor linkage between pediatricians and physicians for adults. In the medical care system, there is a mismatch of diagnostic criteria of primary dyslipidemias between children and adults for medical care expense subsidization, as between The Program for the Specific Pediatric Chronic Diseases and the Program for Designated Adult Intractable Diseases. This could lead some patients subsidized in their childhood to no longer be under the coverage of the aids after transition. This review intends to describe these issues in transitional medicine of primary dyslipidemia in Japan as a part of the efforts to resolve the problems by the Committee on Primary Dyslipidemia under the Research Program on Rare and Intractable Disease of the Ministry of Health, Labour and Welfare of Japan.

Effects of carbon to nitrogen ratio on nitrogen removal in a single-stage microaerobic system: A model-based evaluation

Single-stage microaerobic systems have been proven to be effective for concurrent removal of ammonium and organic carbon from sewage. While mechanistic models derived from activated sludge models (ASMs) have simulated nutrients removal under microaerobic conditions, classic ASMs exhibit limitations in capturing the intricate effects of carbon to nitrogen (C/N) ratio on nitrogen removal performance. To address this issue, a mechanistic model modified from the classic ASMs was proposed to capture the combined inhibitory effects of carbon and ammonium on microaerobic systems. This modified model was established based on experimental data from a single-stage microaerobic reactor encompassing simultaneous nitrification-denitrification and anammox processes. The inhibition coefficient of C/N ratio was integrated into the process rate equations, and its effectiveness was validated through model performance evaluation. Compared to the classic models, the modified one achieved superior predictions for nitrite and nitrate nitrogen concentrations. Simulations revealed that under optimized conditions with a C/N of 4.57 and a dissolved oxygen (DO) of 0.41 mg/L, the system could achieve up to 95.5% of total nitrogen (TN) removal efficiency. Based on the simulation of substrate uptake/production rate, increasing the nitrogen loading rate (NLR) rather than organic loading rate (OLR) was crucial for efficient nitrogen removal. The proposed modified model served as a valuable tool for designing and optimizing similar biological wastewater treatment systems.

Microplastics in anoxic/aerobic membrane bioreactor (A/O-MBR): Characteristics, biofilms, degradation and carrier for antibiotic resistance genes

Wastewater treatment plants (WWTPs)are proposed as one of the ways for microplastics (MPs) to enter the water environment. MPs as the carrier of other pollutants, the inevitable aging process will change the characteristics and fate of MPs. Herein, the physicochemical property alteration, microbial community evolution and antibiotic resistance genes (ARGs) occurrence of the aged MPs surface were analyzed in A/O-MBR system. Remarkable alteration in MPs surface properties, which included the decrease in hydrophobicity and the increase in oxygen-containing functional groups, led to aging of MPs. Aging MPs are more likely to grow biofilms, which further increased the probability of microbial colonization. The genera Hydrogenophaga, Exiguobacterium, Enterobacter, Vibrio, Flavobacterium and Bacillus on MPs surface showed higher degradation potential. ARGs determination results indicated that MPs could enrich ARGs on their surface, and the relative abundance of β-lactam ARGs on different MPs surfaces was the highest. The above research results indicated that MPs in sewage treatment systems not only undergo aging, but also carry ARGs, causing further harm to the environment.

Commissioning and first operation of East Japan Heavy Ion Center at Yamagata University

A world smallest carbon ion radiotherapy facility, East Japan Heavy Ion Center, Yamagata University, started treatment operations in February 2021. The treatment system consists of an ECR ion source, an RFQ and IH-type drift tube linac, a 430 MeV/u synchrotron and a spot-scanning irradiation system. It has two treatment rooms, one is a fixed horizontal beam port and the other is a rotating gantry beam port with superconducting magnets. The ECR ion source is the Kei2-type permanent magnet 10 GHz ECR ion source with a maximum field of 0.8 T. All the improvements of the previous facilities are applied to the ion source, such as helium gas-assisted operation and changes in the shape of an anode electrode and an extraction electrode to reduce the discharge. Owing to these improvements, the ion source has been operated stably during the commissioning and clinical operation. The irradiation system of Yamagata University eliminated the plastic block range shifter to realize a compact gantry, and has 600 energy levels to control the beam range in step of 0.5 mm. In order to optimize the beam transport parameters quickly, automation tools for orbit correction were developed. Machine commissioning and clinical commissioning were carried out in parallel to allow treatment to begin earlier. First, the horizontal fixed beam port was commissioned by verifying the dose distribution of the treatment planning system. Then, the gantry beam port was commissioned by full beam distribution measurement for representing beam angle of 90 degree, and other angles were sequentially released after the compatibility measurement of beam position, beam size, and two-dimensional uniformity. In September 2022, we were able to accept all treatment sites. By August 2023, 1151 cancer patients had been treated. Further improvements to increase available gantry angle and to increase beam efficiency are ongoing.

The role of smart optical biosensors and devices on predictive analytics for the future of aquaculture systems

Recirculating aquaculture systems (RAS) have been rising quickly in the last decade, representing a new way to farm fish with sustainable aquaculture practices. This system is an environmentally and economically sustainable technology for farming aquatic organisms by reusing the water in production. RAS present some benefits compared with other aquaculture methods, for instance, allows the minimization of water usage and disease occurrence, the absence of antibiotics in these systems, shortens the production cycle, functions as a water treatment system, allows the improvement of the feed conversion, and a reduction in the alteration of coastal habitat, among others. However, this is a complex system with complex interactions between the number of fish and water quality parameters, which can compromise the fish welfare. Currently, there is a huge gap in the global aquaculture sector in terms of smart sensors for cortisol (stress hormone), bacteria, water pollutants, volatile organic compounds and micro/nano-plastics assessment. This sector does not measure such critical parameters which brings a weak understanding of the wellbeing of fish. Therefore, it is crucial to implement point of care (POC) sensors for those critical parameters’ assessment via multiparameter solution and predictive analytic capabilities for data supply. This work presents an overall introduction about the impact of the RAS on fish production and its necessity as protein as well as the actual solutions for those problems. Additionally, it reviews the actual state of the art in terms of potential multiparameter POC sensors and predictive analytical approaches that have been investigated in recent years for future application in aquaculture with the aim to guide the researchers on the sector’s needs. Additionally, future perspectives are also described in order to digitize the aquaculture sector with novel optical systems and biosensing elements.

Critical factors for the rehabilitation of Hann Bay (Senegal, West Africa): Solutions for sustainable development

The advanced degradation of Hann Bay (Dakar, Senegal) has reached highly elevated levels, with serious environmental, health, and social consequences. Thus, this study focused on the determinants for rehabilitating Hann Bay and proposed solutions for sustainable development. The target area is currently home to 500,000 inhabitants and hundreds of industrial units, with virtually no suitable wastewater treatment systems. Socio-economic surveys and three rounds of effluent sampling were carried out between 2020 and 2022 at eleven sites in Hann-Bel Air, Dalifort Foirail, Thiaroye sur mer, Sicap Mbao, and Mbao. The study showed increased physicochemical, biological, and bacterial pollution of the heavily contaminated wastewater along the bay. The analytical results of the samples collected for the three series show that almost all sampling points exceed the limit value for TSS (50mg/l) and COD (200mg/l). This indicates that physicochemical and organic pollution are still present in the bay, causing fish to escape into the open sea. BOD measurements are also above the standard (N05-061; 80 mg/l) for series 1 and 2, showing an alteration in bay conditions. Analysis of the microbiological quality of the water in terms of oils and fats showed values well above the current standard (NS 05-061, 20-50 mg/l), which explains the frequent fish kills at the Hann marinas, Hann pêcheurs, and Cité ISRA sites. The same situation was observed in samples of fecal coliforms (CFU/100ml), helminth eggs (eggs/L), nitrogen, phosphorus, zinc, and lead at values outside the norm. Through socio-economic surveys of the populations and workers in the industrial units, the recommended solutions focus on protection and prevention measures, enforcement of regulations, communication and awareness-raising, equipment acquisition, and monitoring and surveillance to rehabilitate the bay.

An innovative “Up-and-Down” adsorption processes for pyrene removal from acid wastewater as new approach in water remediation

Polycyclic Aromatic Hydrocarbons (PAH) pose a risk to human health because they are highly toxic, carcinogenic, and mutagenic. In the context of water remediation, hybrid biopolymers are green materials that can reduce the pollutants in environmental matrices. This study aims to propose a new “up-and-down” wastewater treatment system based on the adsorption of contaminants from the bulk and their transport to the surface to promote future remediation processes. Pyrene was selected as a model pollutant for PAH, and hybrid alginate beads, such as thermally modified hematite montmorillonite alginate calcium carbonate beads (@H@MACaBs), were prepared to investigate their use in water remediation. The synthesized beads were characterized using FT-IR SEM and ion-TOF mass spectrometry techniques, and adsorption studies were performed to quantify the remediation process efficiency and investigate the adsorption processes. Approximately 50 % of pyrene was removed from the aqueous solution without stirring after 90 min of contact. A double increase in pyrene removal was observed when the classical hybrid alginate beads were compared with the new modified hybrid alginate beads. This study contributes to efforts to deploy innovative remediation strategies to reduce the environmental impact of the textile industry, which is a significant contributor to global manufacturing and pollution.

TiO2-Coated Meltblown Nonwoven Fabrics Prepared via Atomic Layer Deposition for the Inactivation of E. coli as a Model Photocatalytic Drinking Water Treatment System

The controlled manufacturing of semiconductor photocatalysts is crucial to their development for drinking water treatment. In this study, TiO2-coated meltblown nonwoven fabrics prepared via Atomic Layer Deposition (ALD) are applied for the inactivation of Escherichia coli (E. coli). It is observed that in the presence of an ultraviolet light-emitting diode (UV-LED) light source (255 nm), 1.35 log E. coli inactivation is achieved. However, exposure to catalyst-coated fabrics in addition to the light source resulted in >4 log E. coli inactivation, suggesting a much higher rate of hydroxyl radical formation on the surface, leading to cell death.

Eco-Flow: Water Management System Using UV Sterilization

Abstract: In our contemporary world, the accessibility of clean and potable water is a pervasive issue, particularly in residential complexes and apartment buildings where shared waterstorage facilities pose a significant challenge. The lack of awareness and diligence in maintaining these communal tanks exposes residents to waterborne diseases. The current hurdle in water monitoring and filtering systems is the creation of a cost- effective, scalable solution that can be easily implemented across diverse environments. This project introduces EcoFlow, an innovative and budget- friendly solution for water level monitoring and purification. The system utilizes UV lights and activated carbon to efficiently filter water, eliminating harmful microorganisms and removing impurities, chemicals, and odors. By addressing the unique challenges of different regions, EcoFlow aims to contribute to the broader adoption of UV and activated carbon-based water treatment systems. Beyond its filtration capabilities, EcoFlow incorporates a real-time water level monitoring system, empowering users with vital information for sustainable and equitable access to clean water

전국 먹는 수돗물의 만족도에 대한 결정 요인 분석과 정책적 시사점

This study offers the first analysis of the determinants of overall satisfaction with drinking tap water using a nationally representative sample based on data from the <2021 Drinking Tap Water Survey> in South Korea. Based on a representative sample from 161 regions across the nation, as our main explanatory variables, we select various perceptions concerning consuming tap water including overall quality, taste, being economical, convenience, and environmental-friendliness. When it comes to consumption of tap water with no treatment (inclusive of boiling it), we find that trust in the quality of the tap water is key to improving overall satisfaction with drinking tap water. With reference to consumption of tap water after filtration, the perception of convenience is found to have a statistically significant positive impact. Regardless of how tap water is consumed, the overall satisfaction improves for high income region respondents perceive that drinking tap water is environment-friendly. In addition, other supply-side factors such as trust in the municipal water treatment system and favorable ratings of the speed of response to complaints were associated with higher satisfaction with tap water. These findings have important policy implications.

Investigating the suitability of online flow cytometry for monitoring full-scale drinking water ozone system disinfection effectiveness

While online monitoring of physicochemical parameters has widely been incorporated into drinking water treatment systems, online microbial monitoring has lagged behind, resulting in the use of surrogate parameters (disinfectant residual, applied dose, concentration × time, CT) to assess disinfection system performance. Online flow cytometry (online FCM) allows for automated quantification of total and intact microbial cells. This study sought to investigate the feasibility of online FCM for full-scale drinking water ozone disinfection system performance monitoring. A water treatment plant with high lime solids turbidity in the ozone contactor influent was selected to evaluate the online FCM in challenging conditions. Total and intact cell counts were monitored for 40 days and compared to surrogate parameters (ozone residual, ozone dose, and CT) and grab sample assay results for cellular adenosine triphosphate (cATP), heterotrophic plate counts (HPC), impedance flow cytometry, and 16S rRNA gene sequencing. Online FCM provided insight into the dynamics of the full-scale ozone system, including offering early warning of increased contactor effluent cell concentrations, which was not observed using surrogate measures. Positive correlations were observed between online FCM intact cell counts and cATP levels (Kendall's tau=0.40), HPC (Kendall's tau=0.20), and impedance flow cytometry results (Kendall's tau=0.30). Though a strong correlation between log intact cell removal and CT was not observed, 16S rRNA gene sequencing results showed that passage through the ozone contactor significantly changed the microbial community (p < 0.05). Potential causes of the low overall cell inactivation in the contactor and the significant changes in the microbial community after ozonation include regrowth in the later chambers of the contactor and varied ozone resistance of drinking water microorganisms. This study demonstrates the suitability of direct, online microbial analysis for monitoring full-scale disinfection systems.

Evaluation of the Performance of Wastewater Treatment Plant at Steel Mill Karachi, Pakistan

The purpose of this study is to evaluate how well Steel Mill Karachi's wastewater treatment system works. Wastewater treatment facilities employ the activated sludge technique. Several influent and effluent locations allowed for the collection of influent and effluent samples. A number of physicochemical parameters, such as total dissolved solids (TDS), biochemical oxygen demand (BOD5), total suspended solids (TSS), chemical oxygen demand (COD), electric conductivity (EC), pH, and other metals, such as potassium (K), iron (Fe), sulphate (SO4-2), calcium (Ca), sodium (Na), zinc (Zn), and magnesium (Mg), were measured in order to evaluate the effectiveness of wastewater treatment plants. In a lab environment, the sample's analysis findings were compared to Sindh Environmental Quality Standards (SEQS) for Pakistan. EC, BOD5, COD, SO4-2, Ca, Mg, Na, K, TDS, TSS, EC, BOD5, COD, SO4-2, Ca, Mg, Na, K, Fe, and Zn were removed to different degrees: 42.93%, 60.33%, 43.63%, 51.53%, 40.5%, 35.56%, 26.33%, 22.12%, 34.09%, 20.75%, 55.87%, 22.12%, and 76.10%. Only two metrics, the COD and Zn concentrations, were over the SEQS limits, keeping other effluent results parameters within the limits. Additionally, it is advised that proper maintenance be carried out to increase the effectiveness of wastewater treatment plants.

BIO-MITIGATION STUDIES OF ARTIFICIAL SWEETENER IN WASTE WATER: A REVIEW

Artificial sweeteners, which are widely used in modern diets and are persistent and may have negative effects on aquatic ecosystems, such as saccharin (SAC), cyclamate (CYC), aspartame (ASP), acesulfame (ACE), sucralose (SUC), alitame (ALT), neotame (NEO), and neohesperidin dihydrochalcone (NSDH), are being found in wastewater effluents at an increasing rate. In order to address this problem, bio-mitigation studies have shown promise as a method of reducing the harm that wastewater-borne artificial sweeteners do to the environment. This review provides a comprehensive overview of recent advancements in bio-mitigation approaches for artificial sweeteners in wastewater treatment systems. Firstly, the prevalence and persistence of artificial sweeteners in wastewater are discussed, highlighting their widespread occurrence and challenges associated with their removal during conventional wastewater treatment processes. Subsequently, various bio-mitigation strategies are examined, including microbial degradation, phytoremediation, and advanced oxidation processes. Microbial degradation, facilitated by diverse microbial communities, has shown potential for degrading artificial sweeteners into less harmful byproducts. several other techniques like Photocatalytic Degradation, Bank filtration, Granular activated carbon (GAC), advanced oxidation processes, such as ozonation and UV/H2O2 treatment, are explored for their ability to degrade artificial sweeteners into non-toxic compounds.

Use of PGPR (Plant Growth Promoting Rhizobacteria) to Increase Yields of Cayenne Pepper (Capsicum frutescens L.) in Monoculture Planting Systems and Under the Shade of Mature Citrus Plants

Cayenne pepper is a vegetable commodity, which can be categorized as a commercial commodity and has the potential to be developed. The problem that arises is that more and more agricultural land is getting damaged. One effort to overcome this problem is to use organic fertilizers such as PGPR. The purpose of this study was to obtain the optimum dose of PGPR (Plant Growth Promoting Rhizobacteria) on the growth and yield (quantity and quality) of cayenne pepper in a monoculture cropping system and under the shade of mature citrus trees. The research was conducted in a Citrus Orchard, Tegalgondo Village, Karangploso District, Malang Regency. The time of the research was carried out in December 2022 - March 2023. This study used a Randomized Block Design (RBD) with two factors, namely the concentration of PGPR (Plant Growth Promoting Rhizobacteria) and the planting system. The first factor is the treatment of the application of the planting system which consists of 2 levels, namely MN (Monoculture) TS (Under the Orange Shade). The second factor was the treatment of PGPR concentration consisting of 4 levels, namely, P0 (without PGPR), P10 (10 ml.-1 concentration), P20 (20 ml.-1 concentration), P30 (30 ml.-1 concentration) and Treatment randomized in each group. and cropping system treatment. The results showed that there was no real interaction between the cropping system and PGPR on the growth of cayenne pepper plants. This is because there is a different effect on each treatment.

Functional and Radiological Outcomes of Distal Femur Fractures treated with Less Invasive Stabilization System versus Dynamic Condylar Screw

Introduction: Fractures in the distal femur are quite rare, comprising around 0.4% of all fractures and 3% of femoral fractures. Managing distal femur fractures has been a subject of debate, but recent developments favor indirect reduction and minimally invasive approaches. The objective is to find a harmonious equilibrium between the mechanical stability of the fractured segments and their biological viability. Given their elevated complication rate, achieving optimal restoration of functional anatomy and ensuring stable fixation is imperative for prompt recovery from distal femoral fractures. Comparison of less invasive stabilization system versus dynamic condylar screw fixation in treatment of distal femur fractures is subject of ongoing debate as to which one is better. Aims and Objectives: To compare the functional and radiological outcomes of distal femur fractures treated with less invasive stabilization system versus dynamic condylar screw fixation. Place and Duration of study: A randomized clinical trial was conducted in the Orthopedic Department of Sheikh Zayed Hospital, Lahore, from July 2, 2020, to January 1, 2021. Material and Methods: A randomized clinical trial was conducted at Sheikh Zayed Hospital in Lahore over a six-month duration. In total 104 patients who fulfilled the inclusion criteria were admitted to the Orthopedic Department via Emergency and OPD. Demographic data and medical histories were taken. The sample size consisted of 52 patients in each group, with random allocation to either the LISS (A) or DCS (B) groups determined by a lottery method. Follow-up appointments were scheduled for all patients at one month, three months, and six months post-surgery. Radiological outcome was evaluated at each follow-up visit while functional outcome assessed at sixth monthly follow up. Data analysis was performed using the SPSS: version 22, considering p ? 0.05 as significant. Results: Frequency of functional outcome was i.e. excellent (32.7%), good (14.4%), fair (2.9%) in group A and excellent (27.9%), good (31.7%), fair (7.7%) in group B (p-value&gt;0.05). Mean fusion time was 18.67±3.04 in group A and 19.62±4.36 in group B (p-value&gt;0.05). Conclusion: Our findings indicate no substantial distinction between the two groups. Using DCS or LISS, both methods yield favorable outcomes with negligible complications in the management of distal femoral fractures. Both systems effectively reduce soft tissue injury.

Determinants of antiretroviral therapy adherence among transgender women in South Africa.

Transgender women bear a huge burden of human immunodeficiency virus (HIV) in South Africa. However, they are not fully engaged in healthcare across the HIV continuum of care. In addition, transgender women face multiple facets of stigma and discrimination as well as socio-economic inequalities, which all have a negative impact on antiretroviral therapy (ART) adherence. The study aimed at exploring and describing the experiences of ART adherence of transgender women living with HIV in the Buffalo City Metro Municipality. The study employed an interpretative phenomenological analysis (IPA) design. Twelve participants were enrolled using a snowballing sampling technique. Data were collected using semi-structured interviews and analysed using an IPA framework. While exploring determinants to ART adherence among transgender women living with HIV in Buffalo City Metro, two superordinate themes emerged: enablers to ART adherence and psychosocial factors promoting adherence. The study found that factors such as differentiated ART service delivery, ARV medicines-related factors, motivators for taking treatment and support systems facilitated ART adherence. Emerging from this study is the need to scale up differentiated, person-centred ART service deliveries that will enhance access and adherence to treatment for transgender women.Contribution:This study provides unique insights on factors enhancing ART adherence among transgender women. There is a paucity of literature on access to HIV care services for key and vulnerable populations, and these findings will be shared in the country and in the region.

Combination of 308-nm excimer laser and piperine promotes melanocyte proliferation, migration, and melanin content production via the miR-328/SFRP1 axis.

Both piperine and a 308-nm excimer laser have significant curative effects on vitiligo. This study mainly explored the molecular mechanism of a 308-nm excimer combined with piperine in regulating melanocyte proliferation. Epidermal melanocytes were cultured in piperine solution, and the cells were irradiated by an XTRAC excimer laser treatment system at 308-nm output monochromatic light. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were for detecting the expression levels of genes or proteins. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and Transwell method was for assessing cell viability and migration capacity. The content of melanin was also detected. The combination of the 308-nm excimer laser and piperine enhanced the cell proliferation, migration, and melanin production of melanocytes and upregulated the level of miR-328, and restraint of miR-328 reversed the influence of the 308-nm excimer laser and piperine. Secreted frizzled-related protein 1 (SFRP1) is a direct target gene of miR-328, and miR-328 can inhibit the expression of SFRP1 and elevate the protein level of the Wnt/β-catenin signaling pathway. The 308-nm excimer laser combined with piperine may be more efficient than piperine alone in the remedy of vitiligo, and the miR-328/SFRP1 and Wnt/β-catenin pathways are participated in the proliferation, migration, and melanin synthesis of melanocytes.

Exploring the adsorption of five emerging pollutants on activated carbon: A theoretical approach

The identification and management of contaminants of emerging concern (CECs) in water systems is crucial for protecting public and environmental health. This paper reports a theoretical approach to studying the adsorption of five CECs: Atrazine (ATZ), Caffeine (CAF), Carbamazepine (CBZ), Sulfamethoxazole (SMX), and Ibuprofen (IBU) - onto Activated Carbon (AC). A set of computational methods, including electrostatic molecular potential maps, conceptual density functional theory, Fukui functions, thermodynamic analysis, and tight-binding molecular dynamics simulations, were employed to analyze the electronic/energetic interactions and mechanisms involved in the adsorption of CECs on AC. The theoretical methodology offered valuable predictions on reactivity sites, stability, and binding mechanisms. Results showed that adsorption primarily occurred through non-covalent interactions like π-π electron donor-acceptor interactions, van der Waals forces, and hydrophobic interactions. Thermodynamic properties suggested the adsorption process was spontaneous and exothermic. However, for the AC/SMX system, the Gibbs free energy reveals that adsorption may be unfavorably compared to the other study systems. Molecular dynamics simulations validated the kinetic stability in the following order CAF (0.13 Å)>CBZ (0.23 Å)>ATZ (0.75 Å)> IBU (1.28 Å)>SMX (1.54 Å). This exploratory theoretical study provides a deep understanding of the interactions between AC and five CECs, aiding in the rational design and optimization of AC-based treatment systems for environmental and industrial applications.

Regulatory Insights for On-Board Monitoring of Vehicular NOx Emission Compliance.

Nitrogen oxide (NOx) emissions from heavy-duty diesel vehicles (HDDVs) have adverse effects on human health and the environment. On-board monitoring (OBM), which can continuously collect vehicle performance and NOx emissions throughout the operation lifespan, is recognized as the core technology for future vehicle in-use compliance, but its large-scale application has not been reported. Here, we utilized OBM data from 22,520 HDDVs in China to evaluate their real-world NOx emissions. Our findings showed that China VI HDDVs had a 73% NOx emission reduction compared with China V vehicles, but a considerable proportion still faced a significant risk of higher NOx emissions than the corresponding limits. The unsatisfactory efficiency of the emission treatment system under disadvantageous driving conditions (e.g., low speed or ambient temperature) resulted in the incompliance of NOx emissions, especially for utility vehicles (sanitation/garbage trucks). Furthermore, the observed intertrip and seasonal variability of NOx emissions demonstrated the need for a long-term continuous monitoring protocol instead of instantaneous evaluation for the OBM. With both functions of emission monitoring and malfunction diagnostics, OBM has the potential to accurately verify the in-use compliance status of large-scale HDDVs and discern the responsibility of high-emitting activities from manufacturers, vehicle operators, and driving conditions.

Characteristics and key driving factors of nitrous oxide emissions from a full-scale landfill leachate treatment system

The characteristics of N2O emission from a full-scale landfill leachate treatment system were investigated by in-situ monitoring over 1.4 years and driving factors responsible for these emissions were identified by statistical analysis of multidimensional environmental variables. The results showed that the maximum N2O emission flux of 2.21 × 107 mg N·h−1 occurred in the nitrification tanks, where 98.5 % of the total N2O was released, with only 1.5 % of the total N2O emitted from the denitrification tanks. Limited oxygen in nitrification tank was responsible for N2O hotspot. The N2O emissions from the parallel lines A and B (both comprising the primary biochemical system) accounted for 52.6 % and 46.6 %, respectively, while the secondary biochemical system contributed only 0.8 % to the total emissions. Higher nitrite concentration in line A and lower nitrogen loading in the secondary biochemical system caused these discrepancies. We found that during the steady state of leachate treatment, intensive N2O emissions of 253.4–1270.5 kg N·d−1 were measured. The corresponding N2O emission factor (EF) ranged from 8.86 to 49.6 %, much higher than those of municipal wastewater treatment. But N2O EF was inconceivably as low as 0.42 % averagely after system maintenance. Influent with low salinity was the key reason, followed by the high MLSS and varying microbial community after maintenance. The dominant genus shifted from Lentimicrobium and Thauera to Norank-F-Anaerolineaceae and Unclassified-F-Rhodocyclaceae. This study underscores the significance of landfill leachate treatment in urban nitrogen management and provides valuable insights into the characteristics and driving factors of N2O emissions from such systems. The findings offer important references for greenhouse gas emission inventories and strategies for N2O control in full-scale wastewater treatment plants.