Environmental Engineering Systems Research Articles

Anaerobic Degradation of Aromatic and Aliphatic Biodegradable Plastics: Potential Mechanisms and Pathways.

Biodegradable plastics (BDPs) have been widely used as substitutes for traditional plastics, and their environmental fate is a subject of intense research interest. Compared with the aerobic degradation of BDPs, their biodegradability under anaerobic conditions in environmental engineering systems remains poorly understood. This study aimed to investigate the degradability of BDPs composed of poly(butylene adipate-co-terephthalate) (PBAT), poly(lactide acid) (PLA), and their blends, and explore the mechanism underlying their microbial degradation under conditions of anaerobic digestion (AD). The BDPs readily depolymerized under thermophilic conditions but were hydrolyzed at a slow rate under conditions of mesophilic AD. After 45 days of thermophilic AD, a decrease in the molecular weight and significant increase in the production of methane and carbon dioxide production were observed. Network and metagenomics analyses identified AD as reservoirs of plastic-degrading bacteria that produce multiple plastic-degrading enzymes. PETase was identified as the most abundant plastic-degrading enzyme. A potential pathway for the anaerobic biodegradation of BDPs was proposed herein. The polymers of high molecular weight were subjected to abiotic hydrolysis to form oligomers and monomers, enabling subsequent microbial hydrolysis and acetogenesis. Ultimately, complete degradation was achieved predominantly via the pathway involved in the conversion of acetic acid to methane. These findings provide novel insight into the mechanism underlying the anaerobic degradation of BDPs and the microbial resources crucial for the efficient degradation of BDPs.

Soret effect on stability of Darcy problem in a bidispersive porous medium with an exothermic chemical surface reaction

AbstractWe examine a saturated bidispersive porous medium undergoing an exothermic chemical reaction at its lower boundary. The fluid flow within this medium is modelled using the Darcy approach. While the Dufour effect is disregarded, the influence of the Soret effect is thoroughly explored. This problem represents a complex multiphysical phenomenon that integrates fluid dynamics, heat and mass transfer, chemical kinetics and thermoelectric effects. This problem finds relevance in various scientific and engineering applications, including enhanced oil recovery, chemical engineering, environmental engineering and energy systems. We introduce a complementary energy theory alongside a linear theoretical framework for the model. The Chebyshev collocation method is employed to derive both linear and nonlinear results. Our findings reveal that the effect of enhancing the Soret coefficient on the system's stability is contingent upon the boundary conditions and the Lewis number. Specifically, an increase in the Soret coefficient generally stabilises the system during stationary convection. Conversely, in scenarios where oscillatory convection prevails, a higher Soret coefficient tends to destabilise the system.

Quantitative mixed-valence state identification of metal ions based on fluorescence response of graphene quantum dots

Quantitative identification of mixed-valence metal ions is essential for gaining deeper insights into critical chemical and biological processes in environmental science, chemical engineering, and biological systems. However, a simple approach of quantitative identification mixed-valence metal ions in solution has remained a challenge. In this study, we have experimentally observed a significant linear correlation (R2 = 0.99) between the concentration of high-valence metal ions (using iron ions as an example) and the fluorescence intensity of graphene quantum dots (GQDs). Utilizing the distinct fluorescence responses of GQDs to high-valence and low-valence metal ions, reliable quantitative detection of mixed-valence metal ions has been successfully achieved. Remarkably, we introduced real-time monitoring of mixed-valence metal ions, revealing a shift from a molar ratio of approximately 4.0 to 2.0. Density functional theory calculations have revealed significant differences in charge transfer between high-valence and low-valence states of metal ions adsorbed onto GQDs. Furthermore, the versatility of this method can extend to various types of GQDs and metal ions, highlighting its universal applicability. This work presents a simple, convenient, and cost-effective approach for quantitatively identifying mixed-valence metal ions in solution, offering a new avenue and opportunity for applications in biochemistry, environmental science, catalysis and materials science.

Practical ethical frameworks for civil engineering and environmental systems

ABSTRACT Ethics is receiving increased emphasis in civil and environmental engineering. However, despite the proliferation of college textbooks and courses encouraging ethical reasoning, engineers in practice often limit their understanding narrowly to their individual actions. Broader issues of global importance are usually addressed in an ad-hoc manner, if at all. Our goal is to present the topic of ethics in a way that appeals to engineers, especially those receptive to ‘systems thinking’. Our broader motivation is to encourage the development of educated, virtuous and caring professionals who engage in contextual ethical reasoning about complex systems. To these ends, we summarise relevant theoretical and applied concepts for ethical analysis, building from a recent chapter that reflects on ethics from an engineering systems perspective (but applied to the healthcare industry). We emphasise virtue ethics and the ethics of care as crucial supplements to duty ethics and utilitarianism. Analytical methods we discuss include Value Sensitive Design, Design for Care, and a multi-level classification of ethical issues into the micro (individual), meso (institutional), and macro (societal) levels. This work collects relevant considerations for designers of civil and environmental engineering systems and researchers interested in developing related design and analysis methods that include practical ethical reasoning. This work is part of a Special Issue on Systems Perspectives: Clarity through Examples (see Dias 2023).

Editorial: Aquaculture environment regulation and system engineering

Editorial: Aquaculture environment regulation and system engineering

Numerical modeling and rational methods of water supply network operations in environmental engineering systems

This research paper uses a numerical modeling process to recreate the actual operating conditions of the water distribution system in the town of Kleosin, located on the border with Bialystok. The performed calculations allowed for the creation of a model for the functioning of the water supply network and for taking rational and optimal decisions affecting the effective operation of the entire system. The numerical modeling process is presented as a common tool to rationally and optimally manage the water distribution system. At the same time, numerous possibilities of computationally modeling and processing accurate real data were presented. The scope of the study included the network model analyzed in terms of the basic quality parameters that the network should meet, such as flow velocity, pressure, unit losses, water age, and operating conditions during simulated events, such as expansion or system failure, broken down into assumed time variants. As part of the paper, a situational variant was presented, which concerned the planned modernization in order to improve the functioning of the system by extending water distribution with new sections. The Epanet computer program distributed by US EPA was used in the research.

New insights into biofilm control and inhibitory mechanism analysis based on the novel quorum quenching bacterium Acinetobacter pittii HITSZ001

Quorum quenching (QQ) has proven its potential as an innovative approach for biofouling control in membrane bioreactor (MBR) for wastewater treatment. In this study, a novel quorum-quenching bacterium, Acinetobacter pittii HITSZ001, was isolated from activated sludge. In contrast to previous studies, in which QQ bacteria were directly applied in the MBR system, in this investigation, this strain was co-cultured with Pseudomonas aeruginosa to illustrate the inhibitory effect of the QQ strain on the key genes involved in biofilm formation. The types of QQ enzymes secreted by A. pittii HITSZ001 and its functional ahlm gene was also identified. To better apply this strain, it was encapsulated in the QQ beads with great activities, which could well adapt to a complex real activated sludge environment and effectively controlled biofilm formation on the membrane. The results of this study suggest that A. pittii HITSZ001 represents a novel and promising strain for biofilm mitigation to promote MBR performance and that it would be economically and technically feasible to expand biofouling control with this strain to plant-scale MBRs and similar environmental engineering systems.

Advanced AI Applications in Energy and Environmental Engineering Systems

Artificial intelligence (AI) constitutes a kind of modelling method widely used in various fields of science including energy and environmental engineering [...]

Discussion on the ecological theory and assessment methods of ecosystem quality and its evolution

Ecological civilization construction and ecological environment governance are basic tasks of state gover-nance in China. China has clearly put forward the goal of improving ecosystem quality and stability. However, there are no consensus on the scientific concept of ecosystem quality and the assessment methods of ecosystem quality evolution, which has puzzled the academic community. Based on the summarization of the scientific concept of ecosystem quality and its evolution, we discussed the concept of ecosystem quality and its ecological theory basis by referencing the concept of production quality, quality management and quality assessment of material production. The scientific connotation of ecosystem quality and its evolution was discussed from the perspectives of ecosystem natural attribute-social attribute-economic attribute and the relationships between them, the cascade relations of ecosystem component-structure-process-function-service-efficacy, the feedback of factor-system-environment, and the logic relation of state ecosystem fluctuation-quantity variation-quality alternation. We proposed perspectives and approaches of multi-objective assessment of ecosystem quality alternation from the aspects of natural resource environment system, typical ecosystem, regional macro-ecosystem, and ecological engineering efficacy.

Modifications of ultraviolet irradiation and chlorination on microplastics: Effect of sterilization pattern

Chlorination and ultraviolet disinfection in drinking water treatment plants (DWTPs) may be highly destructive for microplastics (MPs). Investigating the effect of sterilization patterns on MPs behavior modifications can provide useful information to evaluate their potential risk to drinking water safety. In this study, aged polyethylene (PE), polyethylene terephthalate (PET), polystyrene (PS) and polyvinyl chloride (PVC) were applied, and five well-designed sterilization patterns with low and high doses disinfection were performed. Especially, a combining sterilization pattern including ultraviolet disinfection, low-dose chlorination and high-dose chlorination was designed to simulate the actual disinfection processes in environmental engineering systems. Different sterilization patterns contributed various chlorinated and oxidized modifications on the MPs surface, resulting in distinct effects on their sinking and adsorption performance. After combining sterilization (180 mJ cm−2 UV-C irradiation +9675 mg min L−1 chlorination), the adsorption capacities of ciprofloxacin by PET and PVC were slightly improved, and the one by PS was inhibited. Yet, PET, PVC and PS tend to sink (>95%) after this combining sterilization, implying that these MPs would be retained in DWTPs or water supply pipes. For PE, even though it maintained floating on water, its adsorption of ciprofloxacin was inhibited by combining sterilization (Kf reduced from 0.142 L g−1 to 0.069 L g−1). In general, multiple sterilization patterns can enhance the sinking and inhibit the adsorption performance of MPs, reducing their potential to become vectors of organic contaminants and risk to drinking water users.

Grand Challenges in Environmental Systems Engineering

Grand Challenges in Environmental Systems Engineering

Resilience Requirements Patterns

AbstractIn recent years, achieving resilience has become an important objective in many system development efforts. Resilience is defined as a system's ability to deliver required capability in the face of adversity. Developing resilient systems often depends on first establishing good resilience requirements. Resilience requirements are complex compound requirements and developing high quality resilience requirements is a challenge. In this paper we follow both a deductive and inductive approach to identify the critical content and structure of resilience requirements. We develop a pattern that represents that information and model that pattern in three forms, all containing the same information. The three forms are: 1) natural language, 2) entity‐relationship diagram, and 3) an extension to SysML. Having multiple forms makes the pattern easily developed, understood, and validated by stakeholders who are not modeling experts, while at the same time being formal, precise and computationally consumable. The resulting resilience requirements are consistent with systems engineering methodologies and are easily utilized in Model Based Systems Engineering and Digital Engineering environments.

Environmental systems engineering consideration on treatment of emerging pollutants and risk prevention and control of chemicals

As the impact of emerging pollutants (EPs) on human health and ecosystems becomes significant, attention is being drawn to the treatment of EPs. Unlike conventional pollutants (e.g., chemical oxygen demand, biochemical oxygen demand, SO2, NO x , etc.), EPs have relatively short history of use and production, or have their hazards be identified only recently, and thus are largely beyond the scope of current laws or regulations on environmental pollutants. Synthetic chemicals and unintentionally released chemical substances constitute an important source of EPs. EPs have diverse chemical structures and can take varied forms, including molecules, polymers, and aggregates. EPs can be released into the environment via multiple routes during the life cycle of products that contain corresponding chemicals. In the environment, EPs can be persistent or pseudo-persistent due to continuous release and resistance to degradation. EPs can exert a variety of hazardous effects, including endocrine disruption, carcinogenicity, mutagenicity, etc. In addition, the chronical effects tend to be insidious. All these features have complicated the treatment and control of EPs, resulting in high cost for restoring the contaminated environment. Hence, it is recognized that the key to the treatment of EPs is to prevent potential pollution of the corresponding chemicals. In order to address the issues of EPs, environmental systems engineering (ESE) thinking is required. Environmental issues such as ecological damage and environmental pollution can be regarded as human activity-induced devastation to the structure and function of the Earth surface system, which involves two EPs or chemicals-related processes: (1) The sources, flows and sinks of EPs or chemicals in the human society and natural environmental system, which are informative for controlling policies and strategies to intervene; (2) the effects of EPs or chemicals on the human society system, ecosystem and inorganic environmental system, which provide the basis for setting “objective functions and constraint conditions” for sustainable development of the system. Briefly, ESE for the treatment of EPs and the risk management of chemicals, aims to realize the simulation of systems evolution under various treatment scenarios, by modeling and analyzing the above EPs and chemicals-involved processes in the human society and the natural environmental system. With the constraints on the sustainability of human society, the objective functions, i.e., the economic and social benefits of chemicals and related products, are maximized. Then, the best strategies and practice for the treatment of EPs could be reasonably selected. Several ESE technologies are discussed, among which material flow analysis and life cycle assessment could track the sources, flows, and sinks of chemicals in the human society-economy system, and further quantify their impacts on the environment. Computational toxicology could, via in silico simulations, predict the distribution and fate of EPs, estimate the exposure of human and ecological species to the EPs, and evaluate the adverse effects of EPs on human and ecological species under certain exposure levels. Green chemistry, namely “benign by design”, on the other hand, aims to diminish the use of hazardous feedstocks and the release of waste, and eventually design and produce chemicals with low or zero hazards. All these ESE technologies combined with the relatively conventional process control and terminal treatment technologies, are promising for supporting the risk prevention and control of chemicals, as well as the effective treatment of EPs.

Preface

The 5th International Conference on Environmental and Energy Engineering (IC3E 2021) was held in Yangzhou, China on March 19 to 21, 2021 as a combination of on-line and offline event due to the growing concerns over the coronavirus outbreak (COVID-19), and in order to protect the well-being of our attendees, partners, and staff as our number one priority. IC3E 2021 was organized by Asia Pacific Institute of Science and Engineering (APISE). This conference aimed to provide a platform for researchers from multiple disciplines to share their recent developments and practices in Environmental and Energy Engineering. The participants of the conference were from many parts of the world. The success and prosperity of the conference were reflected through a number of high-quality papers.This scientific event brings together more than 74 national and international researchers in Environmental and Energy Engineering. On top of the local participants coming from different national universities, international participants are also registered from different countries, namely Thailand, India, Nigeria, China, Canada, USA and so on. During the conference, there are keynote speeches, oral presentations, and poster presentations.The proceedings form a compilation of accepted papers for this conference. It includes 3 chapters, covering the areas of Energy and Power Systems Engineering, Environmental and Ecological Systems Engineering, and Advances in Energy and Environmental Studies.List of Committees are available in the pdf.

Automatic Formal Verification of SysML State Machine Diagrams for Vehicular Control Systems

<div class="section abstract"><div class="htmlview paragraph">Vehicular control systems are characterized with numerous complex interactions with a steady rise of autonomous functions, which makes it more challenging for designers and safety engineers to identify unexpected failures. These systems tend to be highly integrated and exhibit features like concurrency for which traditional verification and validation techniques (i.e. testing and simulation) are insufficient to provide rigorous and complete assessment. Model Checking, a well-known formal verification technique, can be used to rigorously prove the correctness of such systems according to design Requirements. In particular, Model Checking is a method for formally verifying finite-state concurrent systems. Specifications about the system are expressed as temporal logic formulas, and efficient symbolic algorithms are used to traverse the model defined by the system and check if the specification holds or not. Systems Modeling Language (SysML) has been widely used in architectural and functional modeling in automotive industries. However, it cannot directly be verified against safety requirements. In this work, SysML is used to establish a unified system model that can present an integrated autonomy software and hardware system of a vehicular control system. A generic model transformation strategy is developed to integrate SysML with one of the state-of-the-art Model Checking tools, NuSMV. Cameo Systems Modeler is an industry leading cross-platform collaborative Model-Based Systems Engineering environment for designing standard-compliant SysML models and diagrams. A native Cameo's plugin is constructed to transform SysML state machines to the input language of NuSMV model checker and also to replay the verification results back into the Cameo's environment. A case study of an executable state machine for a high-level autonomous driving system is built. The NuSMV model checker is used to model check the state machine of the autonomous driving system against design requirements expressed as temporal logic formulas. Upon violation of design requirements, our SysML-NuSMV integration allows to replay counterexamples in the Cameo modeling environment. Thus a bi-directional integration of system modeling language with the model checker is developed and the transformation rules are defined. The case study result shows how this method can help designers and safety engineers to automatically identify hidden design errors in a variety of possible design models.</div></div>

Time-change Reliability Assessment and Analysis of Cryogenic Pneumatic Valve Based on Dynamic Bayesian Network Theory

In order to fully identify the root cause of cryogenic pneumatic valve failure in the process of liquid rocket engine test, and to analyze the dynamic time change of the process of cryogenic pneumatic valve reliability analysis, this paper first analyzes the failure factors of low temperature pneumatic valve in the test process of liquid rocket engine according to the human-machine environment system engineering. By introducing the dynamic Bayesian network theory, and by means of analyzing the time-change failure failure mode of cryogenic pneumatic valve, constructing the time-change reliability model of cryogenic pneumatic valve was constructed in the test process of liquid rocket engine, and the reliability growth technology of cryogenic pneumatic valve was researched by the optimal failure search strategy. Finally, the validity and accuracy of this method are verified by the example. This method can provide a method guide for quantitative analysis and improvement of the reliability of cryogenic pneumatic valve, and provide support for the accurate and objective evaluation and development of liquid rocket engine performance.

КОНЦЕПЦИЯ СОВЕРШЕНСТВОВАНИЯ СПЕЦИАЛЬНЫХ СИСТЕМ ИНЖЕНЕРНОЙ ЗАЩИТЫ ОКРУЖАЮЩЕЙ СРЕДЫ СУДОВ КОМПЛЕКСНОЙ ПЕРЕРАБОТКИ ОТХОДОВ

КОНЦЕПЦИЯ СОВЕРШЕНСТВОВАНИЯ СПЕЦИАЛЬНЫХ СИСТЕМ ИНЖЕНЕРНОЙ ЗАЩИТЫ ОКРУЖАЮЩЕЙ СРЕДЫ СУДОВ КОМПЛЕКСНОЙ ПЕРЕРАБОТКИ ОТХОДОВ

A System and Method for improving the Model Based Systems Engineering Environment capability

AbstractAs the evolution of new technologies such as IOT and Cloud Computational Analysis continue, the Systems have become more and more complex and it is grown much in size. Unfortunately the present day SE Environments, Modeling languages and the related tool sets are not sufficient enough to represent the multiple streams problem at hand in one integrated modeling environment which makes all of the Stakeholders and Engineers & Non‐engineers understand the problem scenarios. This lack of integrated modelling environment and a methodology for an additional representation of multiple problem domains limits off the analysis capabilities, timely communication of the technical and project risks to various stakeholders for decision making. It happens due to the inherent capability & limitations of each modeling languages followed so far by the Model Based System Engineering (MBSE) community & to bridge across them. This research paper focuses on improving the SE modeling environment capability from at least three distinct directions. First, it proposes a way to strengthen the SysML semantics with concrete guidelines which helps to reduce the incompleteness & ambiguous nature of the SysML elements especially in the Non Functional Requirements modeling. Then it explores the possibility of integrating the ontology aspects offered in evolving Life‐cycle Modeling Language (LML) specification to an extended SysML profile to complement its constructs to facilitate communication with non‐system engineers as well. Finally, this paper draws parallel between the LML architectural modeling concepts with the Architecture Analysis & Design Language (AADL) constructs and realizes them in an extended SysML profile. This will facilitate the seamless flow of models at various abstraction levels & translation of architectural model information from LML to AADL analytical environment. A case study implemented using an extended SysML profile & a methodology will be presented to measure its effectiveness.

Evaluating reactor hydraulics in a cost‐effective and environment‐friendly way: Numerical tracer study

AbstractTracer analysis is commonly used to evaluate the hydraulics of environmental and chemical engineering systems. The traditional tracer analysis is conducted through physical experiments that are usually complex, costly, time‐intensive, and may be impractical. Because of the continued advancement of computing technology, computational fluid dynamics (CFD) has demonstrated its applicability in simulating tracer transport. CFD can provide advantages, including no interruptions of existing water treatment process, no impacts of background concentration, and a relatively low cost. However, no reports have quantitatively studied the cost that CFD can save on tracer analysis. This study first proved the accuracy of CFD tracer analysis for an existing ozone disinfection tank and then compared the economic expenses and environmental impacts of CFD tracer analysis with those of a field tracer analysis. It was found that CFD‐based tracer analysis has accuracy on par with the physical‐based study but at relatively low economic cost and environmental impacts.

Constructing True Model-Based Requirements in SysML

Some authors suggest that transitioning requirements engineering from the traditional statements in natural language with shall clauses to model-based requirements within a Model-Based Systems Engineering (MBSE) environment could improve communication, requirements traceability, and system decomposition, among others. Requirement elements in the Systems Modeling Language (SysML) fail to fulfill this objective, as they are really a textual requirement in natural language as a model element. Current efforts to directly leverage behavioral and structural models of the system lack an overarching theoretical framework with which to assess the adequacy of how those models are used to capture requirements. This paper presents an approach to construct true model-based requirements in SysML. The presented approach leverages some of SysML’s behavioral and structural models and diagrams, with specific construction rules derived from Wymore’s mathematical framework for MBSE and taxonomies of requirements and interfaces. The central proposition of the approach is that every requirement can be modeled as an input/output transformation. Examples are used to show how attributes traditionally thought of as non-functional requirements can be captured, with higher precision, as functional transformations.