Journal of Marine Technology and Environment 2025 Vol. 2

Biogas is an increasingly important renewable energy resource in a world facing environmental challenges and the urgent need for sustainable solutions. Produced through the anaerobic decomposition of organic materials, biogas offers an efficient means of valorising organic waste. The production process yields a gas mixture, primarily methane and carbon dioxide, that can be converted into electricity, heat, or fuel, thereby contributing to the reduction of greenhouse gas emissions. Moreover, it supports a sustainable resource cycle, making this technology a highly promising solution for the future of green energy. This study presents a comparative analysis of the operational performance of the Moara-Suceava biogas plant when using agricultural residual biomass (corn and animal waste) versus organic waste from the food industry. The results indicate that, although larger quantities of raw material are required to produce the same volumetric amount of biogas from food industry waste, the latter yields higher lower heating values (5.81–6.20 kWh/Nm³) compared to agricultural residual biomass (4.50–4.91 kWh/Nm³).

This study provides an overview of greenhouse gas (GHG) emissions in Romania between 1970 and 2023, highlighting long-term trends, sectoral contributions, and their implications for climate policy. Using data from the Emissions Database for Global Atmospheric Research (EDGAR), annual values of CO₂, CH₄, N₂O, and F-gases were analysed across eight major anthropogenic sectors. Results show that Romania experienced a peak of approximately 280 MtCO₂eq in 1988, followed by a sharp decline after the political and economic transition in 1989. By 2023, emissions decreased to around 105 MtCO₂eq, representing a 62% reduction. This decline was largely driven by the restructuring of heavy industry, closure of inefficient energy facilities, and adoption of EU-aligned environmental policies. However, transport, agriculture, and waste sectors gained increasing relevance as industrial and power-related emissions fell. Despite progress, sustained challenges remain for achieving Romania’s climate neutrality targets by 2050, particularly in transport decarbonization, agricultural emissions control, and methane capture from waste management.

Detection of underwater mines is very important for military, maritime security, and environment safety applications. However, the development of machine learning models is limited heavily because of the lack of quality labeled sonar datasets, especially in military contexts as the data there is highly confidential and expensive. The problem with current synthetic datasets is that they fail to properly replicate how complex operational underwater environments are which leads to major performance gaps when deployed in the real world. This work shows the design and validation of a low-cost sonar prototype, specifically developed for synthetic dataset generation to work on the issue of the scarcity of data in applications of mine detection underwater. The sonar prototype was built using an Arduino Uno microcontroller, Texas Instruments TUSS4470 ultrasonic analog front end along with a 200khz waterproof transducer in a controlled water tank environment. For echo analysis the system generates 16 cycle bursts and captures approximately 850 samples at 13 μs intervals. The signal processing consists of zero-phase low-pass Butterworth filtering, short-time energy analysis, and adaptive thresholding which is for echo detection. Under varying conditions (like, salinity 0-35 ppt and temperature 10-30°C), the sonar prototype operated successfully and was able to produce high fidelity acoustic datasets. These datasets are suitable for training machine learning models. The sonar prototype provides a proper platform for the generation of acoustic datasets that are realistic under varying environmental conditions and offers a lot of potential for improving the training of machine learning models and generalization in applications of detecting underwater mines.

Environmental engineering programs are extremely important having in view the projected job growth and the increase in global demand for solutions to face environmental challenges. Universities all over the world respond to this need by providing specialized environmental engineering degrees. It is also the case of Constanta Maritime University which is coming to reply to this request by developing the Engineering and Environmental Protection in Industry program. This is a result of the fact that there is a strong need that each of us should be informed about the environment situation, through out environmental awareness. This concept leads to public health and well being of the environment. On the other hand, we assist to population growth- process direct linked to higher energy demand. In this context, the use of renewable energy sources is of great importance since their impact on the environment is considerable less then traditional ones. This paper exposes a planned and carried out activity by Constanta Maritime University and its 4 partners- high schools with energy profile in the country. The activity called “I choose to become a specialist in renewables” is, in fact, a competition aiming to rank essays reflecting the vision of high school students regarding this profession, to analyze a survey conducted to assess the level of environment awareness of the young participants and to facilitate a discussion between the respondents and teachers specialized in the field. The findings are encouraging: the scientific board of the competition found motivating ideas in the presented essays and the survey revealed that the students coming from high schools with such a profile shows maturity and understanding of current environmental issues.

The need to replace traditional refrigerants in marine refrigeration equipment with low-GWP alternatives is growing due to international climate regulations. This paper discusses the current status and potential of R290 (propane) as a long-term substitute in marine air conditioning systems. Compared to other refrigerants, R290 offers higher energy efficiency, low environmental impact, and compatibility with existing system designs. Challenges related to flammability are addressed through compliance with safety standards and technical solutions approved by major classification societies. Calculations of performance parameters under different climatic conditions support the feasibility of switching to R290 as a sustainable alternative.

The publication examines the challenges facing the countries of the Black Sea region and the key role of human resources in the development of the blue economy, analyses how they can be effectively adapted to the new realities related to technologies, skills and policies. The data are based on our own researches, the reports and discussions of the annual National Round Table "The Sea - Border or Door". They show how the challenges can be addressed in order to improve cooperation processes, ensure citizen participation in management processes, increase knowledge about marine resources and accelerate the process of blue growth in the region.

The Black Sea basin is a territory that is distributed between countries with different status and level of economic and social development, in which various historical, cultural and social transformations have been and continue to be realized, in which challenges and risks of a different nature are encountered. Nowadays the territory around the Black Sea is identified as the "Black Sea Region". That is the reason for which it is important to create models through which various risks are managed - economic, social, natural, technological. The research is aimed at preventing natural and technological risks in coastal zones and the water area, as a prerequisite for sustainable development, associated with the ever-complicating technical and technological processes. The development proposes the use of specialized software for risk assessment and analysis and prevention management, the application of which creates a prospect for safer socio-economic development and sustainable growth and the assets we assess and seek to improve.

The maritime and offshore sectors are under increasing pressure to reduce greenhouse gas (GHG) emissions in line with European Union regulations. Starting from January 2025, the revised EU Monitoring, Reporting, and Verification (MRV) framework extends its scope to offshore vessels above 400 Gross Tonnage. In this context, energy efficiency has come increasingly into focus of operational team of offshore vessels equipped with Dynamic Positioning (DP) systems. Aiming to identify the strategies to optimise fuel consumption and to improve energy efficiency in DP operations, the authors adopted a simulation-based approach using Kongsberg K-POS simulator. This research study analyses the performance of a DP-equipped vessel under varying environmental conditions, system settings, and operational modes. The results highlight several practical pathways for reducing energy consumption: lower gain, the use of green mode, and the optimisation of vessel heading relative to external forces. The conclusions confirm that strategic adjustments to DP system parameters and vessel orientation can yield meaningful reductions in fuel consumption and emissions, thereby lowering operational costs and supporting compliance with EU MRV requirements. This research demonstrates the utility of simulator-based analysis in evaluating energy efficiency strategies and provides practical insights for offshore operators seeking to improve sustainability and compliance to EU regulations.

In the present paper, we will tackle the water quality problem in the lentic environment of one of the most well-known lakes in Constanta, Tăbăcărie. The pollution degree will be evaluated to identify the qualitative composition of the microbiota from the analysis sites, respectively, the chlorophyll indicator and the physical-chemical parameters (ammonium and phosphate ions, dissolved oxygen (DO), biochemical oxygen demand (BOD) and pH).

This paper investigates the impact of emerging technologies on seafarers' roles, focusing on how various Asia-Pacific countries are adapting their policies and skills development in the digital era. Using a descriptive research methodology—comprising observation, literature review, and content analysis, the paper explores the challenges and opportunities associated with the adoption of advanced maritime technologies and also examines the evolving landscape of seafarers' skills and policies amidst emerging technological advancements in the maritime sector, with focus on their implications for regional strategic policy development and training frameworks within the Asia-Pacific region. As digitalization, automation, and innovative maritime technologies reshape maritime operations, the demand for a highly skilled, adaptable, and technologically proficient seafarer workforce becomes paramount. The study explores current skills gaps, policy challenges, and opportunities for harmonizing regional standards to support sustainable maritime growth. Furthermore, it proposes a comprehensive strategic policy framework and a modular training program tailored to the unique needs of Asia-Pacific maritime nations, fostering resilience, safety, and competitiveness in the face of rapid technological change. Moreover, the findings also inform policymakers, industry stakeholders, and maritime education providers on effective strategies to equip seafarers with future-ready skills, ensuring the region's maritime sector remains robust and responsive to ongoing technological transformations. Ultimately, the study provide a roadmap for regional stakeholders especially in the Asian countries to harness emerging technologies effectively, ensuring a resilient, competent, and future-ready maritime workforce in the Asia-Pacific maritime context towards success in a dynamic world.

The presented paper analyses the steps by which radio direction estimation algorithms are used to visualize the direction from which a radio signal originates. This study aims to use ULA (Uniform Linear Array) and URA (Uniform Rectangular Array) antennas and integrate them into a simulation in order to find the direction of origin of the signals, what the contrast between the phase and time differences is when the signal reaches the antennas and how the systems for estimating the directions of arrival (DOA) affect the signal at the receptor. The difference between ULA and URA antennas is exemplified by using them in a more complex system that can be implemented physically and not just digitally. These two arrays of antennas have several particularities such as the DOA algorithms used by each antenna, its angled directions and their representation from a matrix point of view. The simulation was conducted as a preliminary study for a hardware implementation of this system using a USRP N 310 software defined radio platform.