Ecological Engineering and Environment Protection

doi.org/10.32006/eeep.2020.1.0514
BIOREMOVAL OF COPPER(II) VIA HYDROGEN FERMENTATION OF ECOLOGICALLY HAZARDOUS MULTICOMPONENT FOOD WASTE
Olesia Havryliuk, Vira Hovorukha, Galina Gladka, Oleksandr Tashyrev

Abstract: The environmental pollution by copper and the increasing amount of environmentally hazardous organic waste destroy natural ecosystems and have negative and even lethal effect on living organisms. The chemical techniques of metal containing waste detoxification are expensive and hazardous being the advanced problem today. The aim was to justify theoretically and confirm experimentally the possibility of toxic Cu²⁺ removal by hydrogen producing microbiome (HPM) via dark hydrogen fermentation of solid multicomponent food waste (MFW). Colorimetric and potentiometric methods were used for pH and redox potential measurement. Volumetric and chromatographic methods were applied to control volume and composition of synthesized gas. Fermentation parameters were calculated with the use of mathematical and statistical ones. The high effectiveness of solid waste destruction and Cu²⁺ removal was shown by spore forming HPM. The MFW were fastly and effectively digested by the microbiome at the absence of Cu²⁺. The weight of MFW was 90 times decreased (Kd = 90). The maximum concentration of H₂was 35% and biohydrogen yield was 76 L/kg of MFW counting on absolutely dry weight (ADW). The fermentation process was inhibited by Cu²⁺ in the form of citrate complex. The biohydrogen yield and efficiency of waste destruction were decreased on 41% (45 L/kg of waste) and 37% (Kd = 57) consequently after addition of 50 ppm Cu²⁺to the culture liquid of the bioreactor during the beginning of final phase (50 hours) of MFW fermentation. The effect of complete inhibition of H₂synthesis was obtained in the case of adding 100 ppm Cu²⁺ to the culture liquid sampled from bioreactor during the final phase (80 hours) of fermentation. Nonetheless, the Cu²⁺ was bioremoved by HPM with high efficiency up to 99.0 % and 99.5% after 5 hours and 30 hours of fermentation where initially the concentrations of Cu²⁺were consequently 50 and 100 ppm. The synthesis of gas was not significantly restored after the addition of Cu²⁺ in both variants of the experiment. Obtained patterns will be used as a basis for the development of novel universal biotechnologies of metal-containing sewage purification with simultaneous destruction of MFW.
Keywords: environmental biotechnologies, biohydrogen fermentation, toxic copper (II) compounds, multicomponent food waste, metal-containing sewage purification

doi.org/10.32006/eeep.2020.2.1520
REMOVAL OF HEAVY METAL Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II) IONS FROM AQUEOUS SOLUTION BY MENTHA PIPERITA EXTRACT
Ersin Yücel, Mine Yücel

Abstract. In this study, the usage of the peppermint (Mentha piperita) for extracting the metal ions [Mg (II), Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II)] that exist at water was investigated. In order to analyze the stability properties, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms were used at removing the metal ions and the highest correlation coefficients (R²) were obtained at Langmuir isotherm. Therefore, it is seen that the Langmuir model is more proper than the Freundlich model. However, it was found that the correlation coefficients of removing Ni and Cd is higher at Freundlich model than Langmuir and low at Dubinin-Radushkevich isotherm. It is established that the biosorption amount increase depends on the increase of biosorbent and it can be achieved high efficiency (95%) even with small amount (0.6 mg, peppermint extract) at lead ions. It is also determined that the peppermint extracted that is used at this study shows high biosorption capacity for metal ions and can be used for immobilization of metals from polluted areas.

Keywords: biosorption, isotherms, equilibrium, Mentha piperita, metal ions

doi.org/10.32006/eeep.2020.2.2127
INVESTIGATION OF NATURAL RADIOACTIVITY OF MINERAL WATERS IN SOUTHERN BULGARIA

Elena Geleva, Hristo Protohristov, Nikolay Goutev, Vladimir Bashev, Stefan Genchev, Dimitar Tonev

Abstract. The activity of naturally occurring radionuclides in mineral waters from certain most frequently used sources in Rhodope Mountains region, Southern Bulgaria has been measured with high precision by means of nuclear and radiochemical methods. The survey is pointed at radium-226 (²²⁶Ra), lead-210 (²¹⁰Pb) and natural uranium (nat. U), which are most important from the point of view of public health in Bulgaria, because of their high toxicity and radiotoxicity in drinking water.
Seventeen water sources were under investigation.
The activity concentrations of ²²⁶Ra and ²¹⁰Pb varied from 13 to168 mBq/L and from ≤ 1.8 to 104 mBq/L respectively. The concentration of nat. U in the mineral water was in the range ≤ 3 to 21 µg/L.
The annual effective doses were calculated for all investigated waters for adult inhabitants assuming yearly consumption of 730 litres.
The results have shown that all values of the annual effective dose of ingestion of mineral waters were below the individual dose criterion of 100 µSv/y reported by World Health Organization (WHO).
The obtained new results are used to assess the radiation status of the investigated waters. They will support timely and adequate measures to reduce the harmful impact of ionizing radiation on the population in cases of increased radioactivity
Key words: ²²⁶Ra, ²¹⁰Pb, nat. U, mineral water

doi.org/10.32006/eeep.2020.2.2833
CULTIVATION OF PLEUROTUS OSTREATUS MUSHROOM ON WASTE PRODUCTS AND COMPOST FOR PHENOL DEGRADATION
Spaska Yaneva, Metodi Mladenov

Abstract. Remediation through application of different kinds of mushrooms is relatively limited due to different objective factors affecting the growth and development of the mushroom species. This paper presents the results of experiments performed to cultivate the Pleurotus ostreatus mushroom on substrates based on various organic wastes and composts. The mushroom mycelium blocks were transferred to soil mixtures and the period of adaptation and sporophores formation was monitored. From sporophores was isolated and purified enzyme tyrosinase, which was tested for phenol degradation activity. The obtained results, show’s that the dense homogeneous blocks formed between the mycelium and the substrate can be used for the recovery of solid waste products for direct application to soils contaminated with phenol.

Key words: Pleurotus ostreatus, bioremediation, toxic compounds degradation, phenol decomposition, compost.

doi.org/10.32006/eeep.2020.2.3444
PHOSPHORUS RECOVERY FROM WASTE AS STRUVITE
Gergana Peeva, Ralitza Koleva, Maya Stancheva, Husein Yemendzhiev, Valentin Nenov
Abstract. The paper gives information on the depletion of phosphorus (P) as an important element for all forms of life and its pollution impact on the environment in case of intensive discharge of phosphorus compounds into water bodies. Two secondary waste sources of Phosphorus are under consideration, namely the domestic wastewater and sludge and animal manure. The characteristics of these two fluids regarding organic matter and nutrient content are summarized. Discussing the techniques for P extraction mostly attention is given to phosphorus precipitation as ammonium magnesium phosphate (struvite). Examples of effectiveness of P precipitation as struvite in Municipal Wastewater Treatment Plants (MWWTPs) with chemical and biological P removal are presented. The examples of struvite production from sewage and manure waste show evidently the great potential of utilization of such a waste as a source of phosphorus. The recovered product is valuable both as it is a slow release fertilizer and with its low content of heavy metals compared to the mineral fertilizers. In respect of the diminishing amount of natural P rocks, the sewagec wastewater and sludge and the animal manure can be regarded as an important secondary source of Phosphorus.
Keywords: phosphorus recovery, wastewater treatment, struvite

doi.org/10.32006/eeep.2020.2.4551
ECOLOGICAL-PHYTOGEOGRAPHIC CHARACTERISTICS OF THE MAIN EDIFICATORY SPECIES IN THE FORESTS OF LOZENSKA MOUNTAIN Plamen Glogov, Mira L. Georgieva
Abstract. The study covers Phase 2 of the ecological-phytogeographic analysis of the dendroflora of Lozenska Mountain. Its purpose is to characterize 15 species-edificators of tree and shrub communities in the mountain and to point out the indicators that most determine the assessment of their ability to long-term adaptability to mountain conditions (convertibility). The performed characterization of the edificators with respect to the reference species shows some heterogeneity in the influence of the factors and the distribution of the groups of species. Indicators, which determinate the most convertibility assessments of edificators are cryoclimatic factor, edaphic regimes and soil pH.
Keywords: trees, shrubs, dendroflora, evaluation

doi.org/10.32006/eeep.2020.2.5262
THE SOILS OF BOTEVGRAD VALLEY
Biser Hristov
Abstract: The paper deals with Botegrad valley soil cover, properties, conditions and vegetation. The soil cover in the Botevgrad region is characterized by considerable diversity in the ravine valleys of the Bebresh River and its tributaries. Alluvial and Diluvial soils occur in the middle of the region in lowest parts. Gray forest soils developed in the Pre-Balkans and the northern slopes of the Balkan Mountains and Light Gray forest soils (Pseudopozolic soils) are spread there too. The most fertile soils are Dark gray forest soils but only in limited area. Shallow soils (Lithosols), are widely spread over reddish-brown quaternary materials, characterized by the presence of many skeletal particles. The soil cover on the slopes is eroded, cut by deep ditches, ravines and valleys.
Main part of the land in the valley is cultivated. Arable lands for cultivation and pastures are about 68.4%, other 22% are used for mainly for forestry. Settlements, industrial zones and other infrastructure occupy 9% of the valley.
Key Words: soil cover, soil property, Botevgrad valley

doi.org/10.32006/eeep.2020.2.6369
PRECISION AGRICULTURE THROUGH AGROECOLOGICAL APPROACH AND MATHEMATICAL MODELING
Alexander Sadovski

Abstract. Precision agriculture is a modern farming management concept using digital techniques to monitor and optimize agricultural production processes. The agroecological approach focuses on the interactions between plants, animals, soil organisms, people, and the environment. It aims to optimize the use of natural resources, enhance biological processes in the soil, and improve biomass, nutrient, carbon, and water cycles. The paper deals with the basic dependencies between some of the factors determining nutrient processes in the soil and the need for fertilizing crops with the main nutrients as components of precision agriculture. An approach to modeling is proposed that meets several requirements and criteria. Mathematical models for calculating fertilizer recommendations give the amounts of the following nutrients: nitrogen, phosphorus, and potassium, required for the target yield on each particular field. Guidelines for improving and refining models for determining the need for fertilizers are given, taking into account all factors governing nutrient flows in the soil.

Keywords: precision agriculture, agroecological approach, mathematical modeling, fertilizer requirements

COVID-19 - ENVIRONMENTAL, ETIOLOGICAL AND EPIDEMIOLOGICAL ASPECTS

Abstract. COVID-19 (declared as a pandemic by the WHO) has become a global health problem with serious economic consequences for more than 200 countries on six continents. The etiological agent SARS-CoV-2 is a RNA virus that is highly contagious and transmitted mainly by airborne droplets, and not only symptomatic but also asymptomatic people are a source of infection. Currently, the prevalence and mortality are growing exponentially, which requires regular and mass testing with reliable tests to identify and isolate individuals infected with SARS-Cov-2.
Numerous scientific data have been presented confirming the ability of coronaviruses to adapt to new tissues and show sustainable tissue tropism, to overcome the evolutionarily constructed barriers of individual host animal species and to acclimatize successfully in different ecological niches. They clarify to a large extent the question of the origin of SARS-CoV-2 and support the hypothesis of its natural origin. Covid-19 is also seen in the light of the WHO's One Health concept, which makes it clear that human health is closely linked to animal health and environmental health.
The main epidemiological characteristics of Covid-19 are presented and emphasis is placed on standard methods of diagnosis and the urgent need for a vaccine and specific drugs for the control and prevention of this dangerous disease.

Keywords: Covid-19

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