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1

Assessment of eutrophication in the Berdan River Basin (Türkiye) using various classification tools

Özbay Özgür, Akçay Ismail, Alp Mehmet Tahir, Göksu Münir Ziya Lugal

Oceanological and Hydrobiological Studies

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2024

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Vol. 53, No. 1

16--23

EN

The trophic status of the Berdan River Basin was determined using univariate and multivariate classification tools. The results indicated that the water quality/trophic status of a downstream section of the Berdan River was characterized as “poor/eutrophic” due to anthropogenic inputs from agricultural, industrial and domestic wastewater discharges. Strong and positive correlations between TRIX values and concentrations of eutrophication parameters suggest that nutrient enrichment of water in the Berdan River during its flow will result in further eutrophication in the coastal region of the NE Mediterranean Sea. Therefore, the trophic and pollution status of the Berdan River, as well as other regional rivers flowing into the coastal area of the NE Mediterranean Sea should be monitored to develop action plans and sustainable management of eutrophication in regional rivers and the oligotrophic Mediterranean Sea.

2

Continuing long-term expansion of low-oxygen conditions in the Eastern Gulf of Finland

Stoicescu Stella-Theresa, Hoikkala Laura, Fleming Vivi, Lips Urmas

Oceanologia

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2024

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Vol. 66 (1)

139--152

EN

o develop an oxygen indicator for the eastern part of the Gulf of Finland (EGOF), a dataset covering 1900–2021 was compiled. The analysis revealed a long-term declining trend in dissolved oxygen concentrations in the EGOF deep layer of 0.022 mg L–1 a–1 and multi-decadal variations associated with the observed changes in hydrographic conditions. About 27% of the decline in oxygen concentrations for 1900–2021 and 40% for 1990–2021 can be explained by the decrease in solubility due to the temperature increase and changes in hydrographic conditions. The water volume and bottom area under low oxygen conditions in 2016–2021, characterized by dissolved oxygen concentrations <= 6 mg L–1, have increased, compared to the selected reference period with almost no human impact in the 1920s–1950s, from 9.8 km3 to 78.0 km3 (from 2.6% to 20.9% of the EGOF total volume) and from 1190 km2 to 4950 km2 (from 13.4% to 56.0% of the EGOF total area), respectively. The environmental status of the EGOF was assessed as not good based on the introduced oxygen indicator. We conclude that, in the long-term, low oxygen conditions have expanded mostly due to the excess load and accumulation of nutrients in the system and temperature-related changes in biogeochemical processes and fluxes. However, on a decadal scale, changes in hydrographic conditions, i.e. stratification and mixing, can significantly impact the sub-surface oxygen conditions in the EGOF and similar estuarine basins.

3

Badania fizykochemiczne ścieków komunalnych na przykładzie Zakładu Oczyszczania Ścieków Płaszów w kontekście redukcji potencjału eutrofizującego. Cz. 1

Pyssa Justyna, Piech Magdalena

Przemysł Chemiczny

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2023

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T. 102, nr 10

1092--1099

PL

Przedstawiono wyniki analiz wybranych parametrów fizykochemicznych ścieków komunalnych z Zakładu Oczyszczania Ścieków Płaszów. Omówiono zjawisko eutrofizacji oraz pierwiastki biogenne. W części badawczej skupiono się na analizie bioprzyswajalnych form azotu oraz fosforu w ściekach. Ponadto porównano właściwości fizykochemiczne ścieków surowych i oczyszczonych biologicznie oraz oceniono skuteczność systemu oczyszczania ścieków w Płaszowie.

EN

The phys. chem. parameters of municipal sewage from the Płaszów Wastewater Treatment Plant were analyzed, such as the content of bioavailable forms of N and P, total suspended solids, BOD5, COD and pH. The phys. chem. properties of raw and biologically treated sewage were compared and the effectiveness of sewage treatment in Płaszów was assessed. During the analyzed period, the av. efficiency of removing the tested pollutants from sewage was high and, in most cases, exceeded 94%

4

Developing an empirical model for assessment of total nitrogen inflow to rivers and lakes in the Biebrza river watershed, Poland

Canchig Jessica, Kustina Rinda, Grygoruk Mateusz

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2023

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Vol. 32, No. 3

201--220

EN

Nitrogen load is crucial for its application in various fields such as agriculture and improving water quality control for authorities responsible for establishing agricultural policies in the area. The calculation of nitrogen load using existing equations is not applicable for all types of rivers, thus requiring the development of a new equation that can be applied to lakes and rivers in the Biebrza river catchment. To determine the new equation, extensive mapping of the catchment area was conducted, which was adjusted to precipitation and runoff in the area, allowing the observed results to be compared. Based on several analyses, the new equation has better accuracy, RMSE of the new model-based estimation decreased by 65.9% in 2005–2015 and 62.2% in 2016–2021 for river and 92% in 2008–2019 and 95% in 2020–2021 for lakes. Therefore, the application of the new calibrated empirical model provides results close to the real values and it can be used in the Biebrza river basin to simulate the total nitrogen runoff.

5

Nutrient inputs from two major rivers into the cilician basin of the north-eastern Mediterranean Sea

Türkeri Mehmet, Marankoz Suat, Özbay Özgür, Akçay Ismail, Alp Mehmet Tahir

Oceanological and Hydrobiological Studies

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2023

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Vol. 52, No. 2

240--244

EN

In this study, dissolved nutrients concentrations weremeasured monthly at downstream points of the tworegional rivers (the Berdan and Göksu rivers) flowing into the Cilician Basin of the North-eastern (NE) Mediterranean Sea. The dissolved nutrients data obtained between September2021 and August 2022 were used to determine riverinenutrient fluxes. This study showed that spatial and temporalvariations were recorded in nutrients concentrations of thetwo regional rivers with the maximum values consistentlyrecorded in the Berdan River having lower volume fluxes.The annual nutrient inputs of the two regional riversindicated that higher amounts of dissolved nutrients werecarried by the Göksu River due to its higher volume fluxrate. The calculated molar ratios from total nitrogen (TN)and phosphorus (TP) fluxes ranged from 13 in the GöksuRiver to 22 in the Berdan River. The higher TN/TP molar ratiocompared to the classic Redfield Ratio of N/P in the BerdanRiver is very likely to modify nutrient dynamics leadingto further eutrophication in the shelf waters of the NE Mediterranean Sea.

6

Analysis of the impact of nutrients deposited from the land side on the waters of Puck Lagoon (Gdańsk Basin, Southern Baltic) : A model study

Dybowski Dawid, Dzierzbicka-Głowacka Lidia

Oceanologia

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2023

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Vol. 65 (2)

386--397

EN

The article analyzes the impact of nutrients (nitrates and phosphates) supplied from the land on the waters of the Puck Lagoon (Gdańsk Basin, southern Baltic). The study is based on the numerical modelling. The model data was verified by comparison with the in situ measurement data. The spatial and temporal variability of the concentrations of nitrate, phosphate, and chlorophyll a were analyzed. We came to the conclusion that the load of nutrients deposited from the land side to the waters of the Puck Lagoon is relatively small (but not negligible compared to the Vistula River). However, even when a little runoff enters the reservoir with a very limited water exchange, like the Puck Lagoon, there are periods when riverine nutrients load significantly affects the functioning of the ecosystem.

7

Hydrochemical conditions of three lakes located in the West Pomeranian region in the annual cycle

Tórz Agnieszka, Bonisławska Małgorzata, Nędzarek Arkadiusz, Rybczyk Agnieszka, Tański Adam

Journal of Water and Land Development

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2023

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no. 56

262--274

EN

The objective of the study was to trace the variability of the hydrochemical conditions in three lakes of the West Pomeranian Voivodeship (Poland) - Starzyca, Maszewskie and Nowogardzkie in the annual cycle. The research was done in 2018-2019, and samples for analysis were collected 4 times a year. All analyses were performed applying standard methods. Such hydrochemical indices were determined as dissolved oxygen, chemical oxygen demand, content of orthophosphates, total phosphorus, nitrite, nitrate, ammonium, chlorophyll a and iron. The study showed that all lakes in the research cycle were characterised by a polymictic type of water mixing, and the trophic level, based on the adopted criteria, indicated advanced eutrophy, which may also be caused by anthropogenic pressure. Oxygen conditions characterised by deoxidation of the waters in the bottom layer in the spring and summer seasons, and clear oxygenation in the surface water layer (in Lake Maszewskie reaching even 188.5% in the spring) confirm the significant advancement of the eutrophication process. The supply of phosphorus and nitrogen in spring from pelagic waters in the waters of the examined lakes influences concentrations of chlorophyll a in the summer. The influence of “internal supply” (bottom waters and bottom sediments) on the amount of nutrients available for autotrophs is clearly visible in the analysed lakes - an increase in nitrogen and mineral phosphorus concentrations in relation to surface waters was observed in the bottom layer.

8

Preliminary Investigation of Bioaccumulation of Microcystins in Hypereutrophic Irrigation Ponds Case Study – the Jordan Valley

Al Kuisi Mustafa, Hyarat Tasneem, Al Qaisi Khaled, Alhejoj Ikhlas, Al-Rshaidat Mamoon

Journal of Ecological Engineering

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2023

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Vol. 24, nr 4

36--53

EN

Microcystis blooms and the related toxin known as microcystin-LR (MC-LR) put the safety of human water consumption and global irrigation practices in jeopardy. MC-LR is widely distributed in various environments, including water, sediments, plants, and other aquatic organisms. The use of water-containing microcystins for agricultural purposes may have to be restricted despite the limited availability of clean water resources. Accordingly, the present work aimed to determine the MC-LR concentrations and recognize the environmental parameters that initiate the growth of toxic cyanobacteria and MC-LR occurrence in 20 irrigation ponds in the Jordan Valley area. The irrigation ponds studied were found in a hypereutrophic condition, with high levels of N:P ratio and low transparency. These cause inseparable effects such as cyanobacterial bloom and MC-LR occurrence. The investigated ponds were classified as hypereutrophic according to General Quality Index (GQI), with two different types of algae covering the surface. The first was the Lemna sp. or duckweeds (Family Araceae) which are free-floating masses, and the second was the cyanobacteria algal bloom. Unpaired t-tests were performed and showed that the concentrations of MC-LR in pond water abundant with cyanobacteria algal bloom in September 2021 were significantly higher (P = 0.7906) than in June for the same year (0.3022 ± 0.0444 and 0.1048 ± 0.0171 ppb, respectively). Two methods for extracting MC-LR were used and showed a significant difference in MC-LR concentration in ponds with an abundance of cyanobacteria algal blooms (0.2273 ± 0.0356 ppb) compared to the ponds with an abundance of Lemna sp. or duckweeds collected in June 2021 (0.1048 ± 0.0171 ppb). Despite all of the efforts made by Jordan Valley farmers to prevent or limit the mass growth of cyanobacteria and its consequences for the eutrophication process in their irrigation ponds through the use of fish breading and chemicals such as copper sulfate, this environmental problem is still harming their crops and irrigation methods and requires immediate government assistance.

9

Phytoplankton Dynamics and Its Relation to Physicochemical Parameters in the Dry Season of Maninjau Lake, West Sumatra, Indonesia

Komala Puti Sri, Silvia Shinta, Windi Sherina

Journal of Ecological Engineering

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2023

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Vol. 24, nr 9

218--231

EN

Physicochemical parameters play a significant role in determining phytoplankton structure and dynamics in the lake. The present study investigated the phytoplankton dynamics and their correlation with physicochemical parameters in the dry season of Maninjau Lake. The parameters measured, including temperature, transparency, pH, DO, TN, and TP concentrations, were collected from seven lake locations, i.e., in the middle of the lake, near domestic, hydropower, endemic fisheries, and aquaculture cage areas, and inlet-outlet rivers. Phytoplankton samples were collected from the middle of the lake, near domestic and aquaculture cage areas. TSI analysis shows that Maninjau Lake was hypereutrophic, with an average TSI of 101.15. The phytoplankton community comprises six classes and 22 species dominated by Microcystis aeroginosa and Synedra acus. Bacillariophyceae had the highest phytoplankton concentration, while Cyanophyceae had the highest density. The diversity and equity index of the phytoplankton community structure were low and less evenly distributed, confirming that the lake was hypereutrophic. The highest diversity index was found in the middle of the lake or the most profound part, while the lowest was near the domestic area. Among the physicochemical parameters, transparency has a strong correlation with dominant phytoplankton.

10

Performance of Compact Bio-Contact Oxidation Reactors for Municipal Wastewater Treatment Under Different Hydraulic Retention Time

Awad Ameera Mohamad, Ibrahim Husham T., Al-Aboodi Ali H.

Journal of Ecological Engineering

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2023

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Vol. 24, nr 12

304--318

EN

This study employed a laboratory-scale continuous upflow bio-contact oxidation reactor to treat 50 L/day of municipal wastewater in Al Rumaitha City, located north of Al Muthanaa Province in Iraq. The reactor configuration consisted of two anoxic-aerobic reactors nested inside each other, with a 1:3 volume ratio of anoxic to aerobic zones. Both the anoxic and aerobic reactors were loaded with K1 bio-media, filling them to 50% capacity for fixing and preserving the biomass. The reactors were operated in a mode that achieved full nitrification-denitrification without any sludge return, relying solely on internal recycling from the aerobic to the anoxic reactor. After biofilm formation on the carriers, three distinct hydraulic retention times (HRTs) were investigated – ranging from 24 to 12 hours – to evaluate their impact on removing biological nutrients from municipal sewage. In this operational approach, the preferred internal recycle ratio and gas/water ratio for effective nitrogen removal were a complete feed rate recycle of 100% and a ratio of 1:5, respectively. The experiment results highlighted that a 24-hour hydraulic retention time was most suitable for the simultaneous removal of organic carbon (COD) and nutrients. During this period, average removal efficiencies were found to be 93.51% for COD, 94.50% for ammonium (NH4+), 60.98% for total nitrogen (TN), and 67.57% for total phosphorus (TP). Furthermore, the aerobic bio-contact oxidation reactors maintained an average dissolved oxygen (DO) concentration of 4.89 mg/L. In contrast, the anoxic bio- contact oxidation reactors exhibited a lower average DO concentration of 0.38 mg/L.

11

Pływające wyspy hydrofitowe jako rozwiązanie problemów eutrofizacji wód - koncepcja metody, zastosowanie i wybrane zagadnienia projektowe

Nawrot Nicole, Janowicz Natalia, Wojciechowska Ewa

Instal

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2023

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nr 3

46--49

PL

Pływające wyspy hydrofitowe są coraz częściej spotykanym elementem krajobrazu - szczególnie na otwartych akwenach miejskich. Posiadają walory estetyczne, są rozwiązaniami opartymi na naturze, poprawiają mikroklimat, a przede wszystkim pełnią funkcję oczyszczającą. Do tej pory jednak nie udało się precyzyjnie sklasyfikować rozwiązań pływających wysp hydrofitowych (z ang. floating treatment islands) w nomenklaturze polskiej. Brakuje również specyficznych wytycznych do ich projektowania. W niniejszym artykule podjęto się wyjaśnienia idei metody, klasyfikacji systemu pływających wysp hydrofitowych, omówiono podstawowe mechanizmy usuwania zanieczyszczeń oraz wybrane zagadnienia projektowe. Praca powstała w wyniku realizacji projektu Preludium 18 [2019/35/N/ST8/01134].

EN

The popularity and presence of floating treatment istalnds in the landscape is increasing rapidly, particularly on open urban reservoirs. They are distinguished by their aesthetic value, belong to nature-based solutions, improve the microclimate, and, most importantly, have a cleansing function. However, in the Polish nomenclature, floating treatment islands solutions have yet to be precisely classified. There are also no specific design guidelines. This article attempts to explain the method’s concept, classify the system of Floating Treatment Wetlands, discuss the basic pollutant removal mechanisms, and discuss selected design issues. The work was created as a result of the Preludium 18 project [2019/35/N/ST8/01134].

12

Wielopoziomowa walka z zanieczyszczeniem wód - nowa odsłona dyrektywy ściekowej

Dawidowicz Magdalena, Kowalczyk Jakub, Pietrzak Dominik

Gospodarka Wodna

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2023

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Nr 3

24--27

PL

Za zanieczyszczenie wód substancjami biogennymi - azotem i fosforem - w dużej mierze odpowiadają rolnictwo i gospodarka ściekowa. By ograniczyć wpływ tych sektorów na stan wód, regularnie prowadzone są przeglądy i aktualizacje programów i polityk w tym zakresie, zarówno na poziomie Unii Europejskiej, jak i krajowym, oraz realizowany jest szereg działań i inwestycji. Z uwagi na dynamiczny rozwój przemysłu i produkcji w ostatnich dekadach problemem dla wód stały się nowe rodzaje zanieczyszczeń. Do walki z ich ograniczeniem służyć ma szeroki wachlarz nowych rozwiązań proponowanych w projekcie znowelizowanej dyrektywy ściekowej.

EN

Agriculture and wastewater management are among the main sources of pollution of waters with biogenic substances such as nitrogen and phosphorus. In order to reduce the impact of these sectors on the status of waters, regular revisions and updates of related programmes and policies are carried out, both on EU and national levels, followed by a series of actions and investments. Due to the dynamic development of industry and production over recent decades, waters now face new types of pollutions. The draft revision of the wastewater directive - the so-called transformation - includes a wide range of new solutions to reduce them.

13

Ochrona wód przed azotanami w dobie przyspieszającej zmiany klimatu

Piórkowski Piotr

Gospodarka Wodna

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2023

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Nr 3

19--23

PL

Dobry stan ekosystemów wodnych ma kluczowe znaczenie dla życia i zdrowia ludzi oraz dla rozwoju gospodarki. Jedną z przyczyn degradacji tych ekosystemów są zanieczyszczenia biogenami, takimi jak azot i fosfor, przyczyniające się do eutrofizacji, a jednym z głównych źródeł tych zanieczyszczeń jest rolnictwo. W artykule przedstawiono zmiany wprowadzone w aktualizacji „Programu działań mających na celu zmniejszenie zanieczyszczenia wód azotanami pochodzącymi ze źródeł rolniczych oraz zapobieganie dalszemu zanieczyszczeniu” w kontekście kierunków polityki Unii Europejskiej i zobowiązań wynikających ze strategii i inicjatyw Europejskiego Zielonego Ładu, takich jak: unijna strategia na rzecz bioróżnorodności 2030, nowy plan działania dotyczący gospodarki o obiegu zamkniętym czy strategia „od pola do stołu”. Artykuł opisuje znaczenie zrównoważonego rolnictwa dla ochrony wód i ograniczenia zjawiska eutrofizacji.

EN

Good status of water ecosystems is of key importance to the life and health of people, as well as to the economic development. One of the reasons behind degradation of these ecosystems is biogenic pollution, including nitrogen and phosphorus, contributing to eutrophication; one of the main sources of this pollution is agriculture. The article presents modifications introduced to the updated "Programme of measures to reduce water pollution with nitrates from agricultural sources and prevention of further pollution" in the context of EU policy directions and obligations resulting from the strategy and initiatives of the European Green Deal, such as: EU Biodiversity Strategy for 2030, new Circular Economy Action Plan, or Farm to Fork Strategy. The article describes the importance of sustainable agriculture for the protection of waters and reduction of the eutrophication phenomenon.

14

Studying the Effect of Mineral Fertilizers on the Development of the Eutrophication Process in the Water Bodies

Kostenko Viktor, Tavrel Maryna, Bohomaz Olha, Kostenko Tetiana, Kostyrka Olesia, Zemlianskyi Oleh

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 4

79--87

EN

The article is devoted to the disclosure of the effect on the vital activity of cyanobacteria by changes in the nutrients in the chemical composition of artificial aquatic biotopes. The research results allowed us to establish that the dissolution of complex mineral fertilizer (nitrogen, phosphorus and potassium) in the range of up to 10 g/L contributes to the active development of cyanobacteria, which is accompanied by complete binding of mineral additives and absorption of oxygen. The addition of fertilizers in the amount of more than 1 g/L contributes to a sharp increase in the growth rate of the cyanobacteria population, which provokes the conditions for the blooming of the solutions. Enrichment of the nutritive base of biotopes ensures rapid growth of biocenosis and accelerated consumption of dissolved substances. The recorded average absorption rate of phosphorus reached more than 17 g/(L·day), and nitrogen – 30 g/(L·day). The formation of sediment and foam in the test vessels was associated with the depletion of nutrients and the death of hydrobionts. This phenomenon can serve as an indicator of oxygen decrease in the water. The results of the experiment confirmed the ability of cyanobacteria to transform nitrogen and phosphorus dissolved in water into bound organic forms with high intensity. This opens up the prospect of creating biological methods and means of wastewater demineralization.

15

Kryzys fosforowy – czym jest i jak się z nim można uporać?

Byczyński Łukasz

Przemysł Spożywczy

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2022

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T. 76, nr 11

14--19

PL

Wyczerpujące się zasoby łatwo dostępnego dla roślin fosforu, wzrost cen pasz i fosforytów oraz zanieczyszczenie fosforanami wód powierzchniowych są objawami szerszego zjawiska, określanego jako kryzys fosforowy. W artykule pokrótce wyjaśniono, jakie znaczenie ma fosfor w produkcji rolniczej i żywieniu zwierząt, z czego wynika obecna sytuacja związana ze zmniejszaniem się źródeł fosforu oraz jego udziałem w procesie eutrofizacji wód, a także dokąd prowadzą te zmiany oraz jak można sobie z tym problemem poradzić.

EN

The depletion of readily available for plants phosphorus, the increase in feed and phosphate prices, and the pollution of surface waters with phosphate are symptoms of a wider phenomenon known as the phosphorus crisis. This article briefly explains the importance of phosphorus in agricultural production and animal nutrition, what causes the current situation with decreasing sources of phosphorus and its contribution to process of eutrophication of waters, as well as where we are going and how we can deal with this problem.

16

Seasonal assessment of the trophic status in the coastal waters adjoining Tuticorin harbor in relation to water quality and plankton community in the Gulf of Mannar, India

Sathishkumar Rengasamy Subramaniyan, Sundaramanickam Arumugam, Mohanty Ajit Kumar, Sahu Gouri, Ramesh Thangavelu, Balachandar Kumar, Nithin Ajith, Surya Parthasarathy, Silambarasann Krishna

Oceanologia

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2022

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No. 64 (4)

749--768

EN

Seasonal variations in hydrography, trophic status, and plankton community structure were studied along the Tuticorin coastal waters (TCWs) in the Gulf of Mannar (GoM). Samples were collected in 2015 and 2016 to analyze physico-chemical (temperature, pH, salinity, suspended particulate matter (SPM), dissolved oxygen (DO), nutrients, etc.) and biological parameters (chlorophyll-a, phytoplankton, and zooplankton). The trophic index (TRIX) and eutrophication index (EI) were calculated to describe the eutrophication status of TCWs. Temperature, pH, salinity, DO, and SPM showed seasonality due to the impact of the northeast monsoon. A massive bloom of Trichodesmium erythraeum was observed, with a visible impact on water quality and the plankton community. The cluster and principal component analysis indicated the bloom event as a distinct phenomenon. ANOVA results showed significant seasonal variations rather than spatial variations. According to the trophic indices, the area had a low trophic level in 2015 and a high trophic level in 2016. The Tuticorin inshore waters had the highest TRIX and EI values during the dominance of cyanobacteria bloom in the post-monsoon 2016. The trophic indices had a positive relationship with phytoplankton abundance but showed an inverse relation with zooplankton abundance. The overall range of the TRIX index (3.18–5.96) indicated that the environment was oligotrophic to eutrophic, and EI values (0.72–21.61) indicated that the state of coastal waters was moderate to poor. This study states that periodic monsoonal flow and frequent algal bloom events have a significant impact on the GoM coastal waters.

17

Nutrients from beach recreation in the context of the limnological status of a mesotrophic lake

Serafin Artur, Grzywna Antoni, Augustyniak Renata, Bronowicka-Mielniczuk Urszula

Journal of Water and Land Development

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2022

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no. 54

160--171

EN

The study objective was to analyse the number of tourists present in the shore zone and bathing areas of lakes with regard to their tourist carrying capacity and the amount of biogenic substances potentially entering the ecosystem from the beach and bathing areas. The procedures from project between the EU and Poland, in the module “Development of the sanitary supervision of water quality” were used in three categories: physiological substances - sweat and urine; water-soluble and insoluble organic compounds; and biogenic elements - nitrogen and phosphorus. The research was conducted in two model mesotrophic lakes, Piaseczno and Zagłębocze, located in the Łęczna-Włodawa Lakeland (eastern Poland). The data were analysed in reference to biological trophic status indices defining the limnological status of lakes in the summer of 2014 and 2016. Analyses of gross primary production of phytoplankton using the light and dark bottles method and the analysis of chlorophyll a concentration were applied using the laboratory spectrophotometric method. The relatively small number of tourists recorded in the shore zone of both lakes did not exceed their tourist carrying capacity, and their potential contribution of biogenic substances to the lake ecosystems was small. Biological trophic indices for both lakes indicated that they had been continually late-mesotrophic for decades. The amount of biogenic substances directly linked to beach tourism usually has a minor effect on the limnological status of mesotrophic lakes. Due to the specific character of lake ecosystems, however, even small amounts of these substances can contribute to the destabilisation of the biocenotic system.

18

Utilizing the Eutrophication in Bioresources Recovery and Biogas Production – A Case Study in Egypt

Khalil Mohamed M., Ficara Elena, Colaninno Nicola, EL-Baz Amro

Journal of Ecological Engineering

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2022

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Vol. 23, nr 12

299--313

EN

In this work, the nutrients and eutrophication problem are integrated into a nature-based solution by incorporating microalgae-based nutrient removal from wastewater and collecting the residue in an anaerobic digestion plant to produce biogas that is directly exported to an existing gas-fired power plant and closes the bioresource loop. El Burullus lake in Egypt was selected as a case study because it is rich in nutrients and suitable for the integrated system. The theoretical results were promising as for one-hectare, nutrient pollution could be reduced with a total nitrogen removal rate of 4 kg•d-1, a total phosphorus removal rate of 1.1 kg•d-1, and a total COD removal rate of 9.3 kg•d-1. The digester volume corresponding to the biomass produced was 120 m3 per hectare of algae pond and the methane yield () from anaerobic digestion was 73 m3•d-1.

19

Recirculating Airlift for Aeration of Shallow Water Bodies

Tavrel Maryna, Kostenko Viktor, Bohomaz Olha, Kostenko Tetiana, Zemlianskyi Oleh, Pidhornyy Mykola

Ecological Engineering & Environmental Technology

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2022

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Vol. 23, iss. 5

177-187

EN

The article is devoted to solving the issue of ensuring the efficient operation of aeration equipment in the conditions of shallow water bodies with an average depth of only a few meters. The article offers a technical solution for reducing the size of airlift aerators and increasing their performance by creating a recirculation movement of water inside the unit. With the help of a laboratory model, it was established that the dynamics of oxygenation of water in the pool with the help of a recirculating airlift is subject to a logarithmic dependence on the size of the flow regulator. It was possible to increase the oxygen concentration in the pool by 2.6 times within three hours as part of the simulation. The rate of water oxygenation was much higher than for a conventional airlift of the same size. The offered cost-efficient aeration unit, which uses wind flow as an energy source, can be used for fish farms and other applications.

20

Experimental Testing of Water Body Aeration Airlift Technology

Kostenko Viktor, Tavrel Maryna, Bohomaz Olha, Zavialova Olena, Kostenko Tetiana, Myhalenko Kostiantyn, Kostyrka Olesia

Ecological Engineering & Environmental Technology

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2022

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Vol. 23, iss. 3

184--192

EN

The article is devoted to substantiation of parameters of water body aeration technology at high, as well as low, air temperatures. As a result of studies, the design of the water aerator based on a two-stage airlift has been improved. A study of its physical model has been conducted. The cost indicators of the set-up and its components have been obtained. It has been established that at various design parameters, the proposed scheme of operation allows to oxygenate water more effectively when compared to conventional design. A new type of water aerator based on two-stage airlift has been proposed. The linear dependence of the dynamics of the aerator flow rate on the supply of compressed air by the compressor, as well as the logarithmic dependence regarding the water oxygenation have been established. The indicator of effective rate, which allows for evaluating efficiency of water body oxygenation has been substantiated. The study results open the possibility of using an aerator with improved design to prevent eutrophication of water in open water and industrial reservoirs, e.g. in construction.