Ecological Engineering and Environment Protection

Abstract. The poultry industries are growing rapidly due to its availability of lean meat with low cholesterol content. However, the problems also coming along with the poultry manure production as a waste from poultry industries. Тhe increase in the demand of poultry products have led to fast and concentrated growth of the poultry industry, which deliver superabundant manure supplies. Poultry waste is one of the best organic manure and also much valuable resource. At present the poultry farming supply vital sprig of animal protein and also the most freely reared livestock species amongst the all livestock species. In spite of its huge benefits like production of meat, eggs and job generations it frequently creates some environmental risks that adversely affect both humans and animals, because the poultry farming is the main cause of offensive odor, water, soil, and air pollution. The conversion of poultry waste into biogas and biofertilizer is considered one of the most effective waste management and recycling strategies.

The aim of this manuscript is to deliver a comprehensive overview of the state of the art, the technical feasibility and some perspectives of the anaerobic digestion and anaerobic co-digestion of poultry waste for biogas production including our own results in this field.

Keywords: poultry waste, environmental pollution, chicken manure, AD, AcoD, complex mixtures, biogas production, biofertilizer

doi.org/10.32006/eeep.2026.1.3037
Topography Analysis of Terrain Within Protonilus Mensae region of Mars Using Fractal Dimension and Lacunarity

Rosen Iliev, Boyko Ranguelov

Space Research and Technology Institute, Bulgarian Academy of Sciences, Sofia, Bulgaria

Abstract: This study investigates the surface complexity of the Protonilus Mensae region in the northern hemisphere of Mars using an integrated approach based on fractal dimension (FD) and lacunarity analysis. Digital elevation model (DEM) data derived from the Mars Orbiter Laser Altimeter (MOLA), with a spatial resolution of 463 m, were analyzed using Python-based algorithms. Surface roughness was analyzed using a variogram-based fractal method. The results show that the topography of Protonilus Mensae exhibits fractal behavior, with FD values ranging from 2.11 to 2.70 and a mean value of 2.35. Spatial patterns of FD reveal predominantly low to moderate surface complexity. Lacunarity analysis was employed to characterize spatial heterogeneity and the distribution of topographic gaps. (Lacunarity means empty spaces (gaps) in DEM with similar fractal dimensions but different surface view.) The results show a strong dependence of lacunarity on elevation, with maximum heterogeneity occurring at intermediate elevations associated with fretted (not smooth) terrain. Lower and higher elevations exhibit reduced lacunarity. The combined fractal and lacunarity results suggest that the present-day morphology of Protonilus Mensae represents a degraded landscape shaped by a balance between roughness-enhancing processes and smoothing processes. This integrated quantitative approach provides new insights into the geomorphological evolution of not flat terrains on Mars.

Keywords: Protonilus Mensae, Mars, fractal dimension, lacunarity, variogram, smooth terrains.

doi.org/10.32006/eeep.2026.1.3844
VALORIZATION OF TARO (Colocasia esculenta L.) AGRICULTURAL WASTE INTO ENERGY DENSE BRIQUETTES: A SUSTAINABLE FUEL QUALITY ASSESSMENT

Arum Widyasmara¹, Erna Styani², Chairil Anwar², Winny Iftari³, Kurnia Widhi Astuti¹, *Poppy Sri Lestari²

¹Department of Chemical Analysis, Polytechnic of AKA Bogor, Bogor 16154, Indonesia.

² Department of Industrial Waste Treatment, Polytechnic of AKA Bogor, Bogor 16154, Indonesia.

³Department of Food Industry Quality Assurance, Polytechnic of AKA Bogor, Bogor 16154, Indonesia.

Abstract. This study investigates the potential of taro (Colocasia esculenta L.) peel, a significant agricultural waste, as a raw material for high-quality solid fuel briquettes. To optimize characteristics, briquettes were pre-treated by oven-drying (90ºC-120ºC, 30-60 min) and assessed via proximate analysis, DSC, and Ignition Rate testing. Results confirmed successful property upgrades, identifying 120ºC for 45 minutes as optimal for energy concentration. This condition yielded the highest Fixed Carbon (55.08%) and total thermal output (1,689.176 J/g by DSC), plus the maximum Ignition Rate (0.0008778 g/second), confirming superior combustion kinetics. The 120ºC variant's superior energy content and confirmed thermal stability (onset 206.840ºC) establish it as the most promising fuel. Findings validate the technical feasibility of transforming taro peel waste into an energy-dense solid fuel, demonstrating a viable strategy for sustainable waste management and renewable energy generation.

Keywords: Taro Peel Waste, Solid Fuel Briquettes, Valorization, Fixed Carbon, Thermal Stability, Ignition Rate, DSC

doi.org/10.32006/eeep.2026.1.4557

OPTIMIZING TRANSPLANTING AGE FOR ENHANCED YIELD AND SEED QUALITY OF T. AMAN RICE VARIETIES IN SUBTROPICAL BANGLADESH: A STUDY ON VARIETAL RESPONSES

Nasir Uddin Soykot^1,*, Md. Sharieutullah¹, Deen Mohammad Deepo² & Dr. A. K. M. Ruhul Amin³

¹Institute of Seed Technology, Sher-E-Bangla Agricultural University, Dhaka, Bangladesh

²Department of Agricultural Science, Daffodil International University, Dhaka, Bangladesh

³Dept. of Agronomy, Sher-E-Bangla Agricultural University, Dhaka, Bangladesh

Correspondence: nasiruddinsoykot.sau.74@gmail.com*

Abstract. A field experiment was conducted during the Aman season (July–December 2019) in a subtropical region of Bangladesh to address the prevailing challenge of low national T. Aman rice yield and the common farmer practice of using over-aged seedlings. The study aimed to determine the optimal seedling age and genotype combination for maximizing both grain yield and seed quality. Three rice varieties (BRRI dhan32, BRRI dhan62, and BRRI dhan80) were evaluated across four transplanting ages (20, 25, 30, and 35 days) using a two-factor Randomized Complete Block Design (RCBD). Results demonstrated that the variety BRRI dhan32 was statistically superior, yielding the highest grain (4.68 t/ha) and exhibiting the best seed germination (88.33%), primarily due to its robust yield components, including a greater number of effective tillers and filled seeds per panicle. Seedlings transplanted at 30 days old (A₃) significantly outperformed other ages, promoting optimal growth and development and resulting in a maximum yield of 4.83 t/ha and germination of 92.01%. Crucially, the interaction between BRRI dhan32 and 30-day-old seedlings (V₁A₃) produced the highest combined performance, recording an exceptional grain yield of 5.12 t/ha, superior germination (92.86%), and the highest vigor index (2152.49), largely attributable to enhanced 1000-seed weight. This research conclusively recommends cultivating BRRI dhan32 with 30-day-old seedlings as a practical and effective strategy to significantly boost the productivity and quality of T. Aman rice, thereby enhancing national food security in subtropical environments.

Keywords: Seeding, Yield Quality, T. Aman, Harvesting, Rice.

doi.org/10.32006/eeep.2026.1.5867

MODELING AND ANALYSIS OF FLUX AND POWER DISTRIBUTION FOR HTR-10 REACTOR CORE

        Mohamed A. Alzamly¹, Hesham Elkatib²

¹Fuel Cycle Safety Department, Nuclear and Radiological Safety Research Center, Egyptian Atomic Energy Authority, Cairo, Egypt

²Reactor Department, Nuclear Research Center, Egyptian Atomic Energy Authority, Cairo, Egypt

        Abstract. MCNP6 computer code is used to model HTR-10 core reactor. UO₂ fuel is used. We predict the Flux and power distribution for normal core loaded by UO₂ fuel pebbles of the reference HTR-10 reactor. The MCNP model consisted of the reactor structure which included the graphite reflector, the borated carbon bricks surrounding it and the pebble-bed core. The results show an analogue between the thermal neutron flux distribution and the power distribution, where the thermal neutrons are responsible for causing the fission, and hence power generation. The thermal neutron flux and power generation have its maximum value at the core center and decreases as we move away from the center to core boundary. The thermal flux is increased near the reflector because the neutron reflector scatters back (or reflects) into the core many neutrons that would otherwise escape. The neutrons reflected back into the core are available for chain reaction (reflector savings).

         Keywords: Pebble-bed, HTR-10, Flux distribution, power distribution, thorium-based fuel.

doi.org/10.32006/eeep.2026.1.6874
RESEARCH ON THE ALPHA OMEGA WATER® CRYSTAL INSTRUMENT: RESULTS AND ANALYSES WITH FT–IR, EIS, NMR, AND DFT

Ignat Ignatov¹, Yordan G. Marinov²

¹Scientific Research Center of Medical Biophysics (SRCMB), Sofia, Bulgaria

²Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria

Abstract: Alpha Omega Water® represents an innovative approach within environmental engineering aimed at improving the physicochemical properties of water as a key natural resource. As a high-quality treated water product, it is associated with processes that help maintain cleaner, more environmentally friendly water systems.

This study examines the properties of Alpha Omega Water® using Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (NMR) spectroscopy, electrochemical impedance spectroscopy (EIS), and quantum chemical calculations based on Density Functional Theory (DFT). Treated water was compared with untreated control samples to evaluate possible differences in molecular organization and electrical behavior.

The results showed measurable differences in spectroscopic characteristics, impedance response, and modeled water-cluster parameters between treated and control samples under the applied experimental conditions.

These findings may be consistent with differences in the local hydrogen-bond environment and the associated physicochemical behavior of water.

These results indicate that Alpha Omega Water® possesses properties relevant to processes that improve the physicochemical characteristics of water, thereby contributing to the maintenance of a cleaner, more environmentally favorable water environment.

Keywords: Alpha Omega Water, hydrogen bonds, water clusters, FT-IR, NMR, DFT, EIS

doi.org/10.32006/eeep.2026.1.7582
FEASIBILITY OF INTEGRATING INTERNET OF THINGS (IoT) -ENABLED DOCKED ELECTRIC SCOOTER SYSTEMS WITH PUBLIC TRANSPORT: A CASE STUDY OF SOFIA, BULGARIA

Tsvetan Iliev

The Institute of Robotics, Bulgarian Academy of Science (IR-BAS), Sofia, Bulgaria

Abstract: Urban transport systems face increasing challenges related to congestion, emissions, and inefficient first- and last-mile connectivity. This study proposes a methodological framework for evaluating the integration of Internet of Things (IoT)-enabled docked electric scooter systems with urban public transport through a composite index combining travel time, emissions, and cost. A case study based on the transport network of Sofia, Bulgaria, compares a conventional public transport scenario with an integrated metro and shared e-scooter scenario. The results demonstrate that the integrated approach can reduce travel time by approximately 27% and transport-related emissions by approximately 29%, while providing improved overall mobility performance despite slightly higher direct user cost. The proposed framework offers a simple and adaptable methodology for evaluating integrated micromobility solutions in sustainable urban transport systems.

Keywords: micromobility, electric scooters, urban mobility, public transport integration, IoT, sustainable transport

doi.org/10.32006/eeep.2026.1.8392
IN VITRO ANTIMICROBIAL ACTIVITY OF L-MALIC ACID-BASED COMPOSITION

Teodora P. Popova^1*, Mila D. Kaleva², Fabio Huether³, Alexander I. Ignatov⁴, Ignat Ignatov⁴

¹Faculty of Veterinary Medicine, University of Forestry, 10 Kl. Ohridski Blvd., 1756 Sofia, Bulgaria

²The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

³EVODROP AG, 8306 Brüttisellen, Switzerland

⁴Scientific Research Center of Medical Biophysics (SRCMB), 1111 Sofia, Bulgaria

Email of corresponding author: tpopova@ltu.bg

Abstract. The increasing prevalence of antimicrobial resistance has intensified the search for safe and effective alternatives to conventional antimicrobial agents, including natural compounds. L-malic acid, a naturally occurring in fruits and plant tissues, has attracted interest in this respect. The present study evaluated the in vitro antimicrobial activity of a formulation containing L-malic acid against reference strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans using a suspension assay. The tested formulation comprised 60% (w/w) L-malic acid, 30% (w/w) starch, and 10% (w/w) organosilica, obtained from product IONSIEVE MALOX^®. The formulation was evaluated at nominal L-malic acid concentrations of 1, 2, and 3 mg·L^-1 and exposure times of 1, 4, and 24 h using final inoculum levels of 5×10² or 1×10² CFU/mL. Under the tested conditions, the formulation reduced the number of recoverable cells of all examined microorganisms in a concentration-, time-, and inoculum-dependent manner. At 3 mg·L^-1, no recoverable E. coli cells were detected after 1 h at 5×10² CFU/mL, whereas C. albicans reached undetectable levels after 4 h and P. aeruginosa and S. aureus after 24 h. At 1×10² CFU/mL no recoverable C. albicans cells were detected after 1 h, while in the other tested microorganisms - after 4 h. The formulations at 1 and 2 mg·L^-1 also reduced recoverable counts of all tested strains, although with weaker early effects. These findings indicate that, under in vitro suspension-test conditions, L-malic acid exhibited significant antimicrobial activity against the tested bacterial and yeast strains and merit further investigation under application-relevant conditions.

Keywords: L-malic acid, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, antimicrobial activity

CONTENTS

doi.org/10.32006/eeep.2026.1.4557

OPTIMIZING TRANSPLANTING AGE FOR ENHANCED YIELD AND SEED QUALITY OF T. AMAN RICE VARIETIES IN SUBTROPICAL BANGLADESH: A STUDY ON VARIETAL RESPONSES

doi.org/10.32006/eeep.2026.1.5867

MODELING AND ANALYSIS OF FLUX AND POWER DISTRIBUTION FOR HTR-10 REACTOR CORE