Editorial

4 pages, 194 KiB

Open AccessEditorial

Agro-Industrial Wastewater Treatment with Decentralized Biological Treatment Methods

by Christos S. Akratos, Athanasia G. Tekerlekopoulou and Dimitrios V. Vayenas

Water 2021, 13(7), 953; https://doi.org/10.3390/w13070953 - 31 Mar 2021

Cited by 6 | Viewed by 1754

Food processing consumes high volumes of water, making agro-industries the third biggest industrial user of water after oil refineries, primary metals and chemicals industries [...] Full article

(This article belongs to the Special Issue Agro-Industrial Wastewater Treatment with Decentralized Biological Treatment Methods)

Research

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16 pages, 1468 KiB

Open AccessArticle

Adsorption of Patent Blue V from Textile Industry Wastewater Using Sterculia alata Fruit Shell Biochar: Evaluation of Efficiency and Mechanisms

by Balendu Shekher Giri, Mandavi Goswami, Prabhat Kumar, Rahul Yadav, Neha Sharma, Ravi Kumar Sonwani, Sudeep Yadav, Rajendra Prasad Singh, Eldon R. Rene, Preeti Chaturvedi and Ram Sharan Singh

Water 2020, 12(7), 2017; https://doi.org/10.3390/w12072017 - 16 Jul 2020

Cited by 16 | Viewed by 3046

Abstract

Biochar prepared from Sterculia alata fruit shell showed a better performance for dye removal than the biomass from Sterculia alata fruit shell. The important process parameters—namely the pH, the amount of biochar, the initial dye concentration and the contact time—were optimized in order [...] Read more.

Biochar prepared from Sterculia alata fruit shell showed a better performance for dye removal than the biomass from Sterculia alata fruit shell. The important process parameters—namely the pH, the amount of biochar, the initial dye concentration and the contact time—were optimized in order to maximize dye removal using biochar of Sterculia alata fruit shell as the bio-sorbent. The results from this study showed that the maximum adsorption of dye on the biochar was obtained at a biochar dosage of 40 g/L, at a contact time of 5 h, and an initial dye concentration of 500 mg/L (pH 2.0; temperature 30 ± 5 °C). The increase in the rate adsorption with temperature and the scanning electron microscopic (SEM) images indicated the possibility of multilayer type adsorption which was confirmed by better fit of the Freundlich adsorption isotherm with the experimental data as compared to the Langmuir isotherm. The values n and R² in the Freundlich isotherm were found to be 4.55 and 0.97, respectively. The maximum adsorption capacity was found to be 11.36 mg/g. The value of n > 1 indicated physical nature of the adsorption process. The first and second order kinetics were tested, and it was observed that the adsorption process followed the first-order kinetics (R² = 0.911). Full article

(This article belongs to the Special Issue Agro-Industrial Wastewater Treatment with Decentralized Biological Treatment Methods)

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16 pages, 3462 KiB

Open AccessArticle

Feed Types Driven Differentiation of Microbial Community and Functionality in Marine Integrated Multitrophic Aquaculture System

by Yale Deng, Fan Zhou, Yunjie Ruan, Bin Ma, Xueyan Ding, Xiaomei Yue, Wenjun Ma and Xuwang Yin

Water 2020, 12(1), 95; https://doi.org/10.3390/w12010095 - 26 Dec 2019

Cited by 12 | Viewed by 3644

Abstract

Integrated multi trophic aquaculture (IMTA) improves the production of aquatic animals by promoting nutrient utilization through different tropical levels. Microorganisms play an important role in elements cycling, energy flow and farmed-species health. The aim of this study was to evaluate how feed types, [...] Read more.

Integrated multi trophic aquaculture (IMTA) improves the production of aquatic animals by promoting nutrient utilization through different tropical levels. Microorganisms play an important role in elements cycling, energy flow and farmed-species health. The aim of this study was to evaluate how feed types, fresh frozen fish diet (FFD) or formulated diet (FD), influence the microbial community diversity and functionality in both water and sediment in a marine IMTA system. Preferable water quality, higher animal yields and higher cost efficiency were achieved in the FD pond. Feed types changed the pond bacterial community distribution, especially in the rearing water. The FFD pond was dominated with Cyanobacteria in the water, which played an important role in nitrogen fixation through photosynthesis due to the high nitrogen input of the frozen fish diet. The high carbohydrate composition in the formulated diet triggered higher metabolic pathways related to carbon and lipid metabolism in the water of the FD pond. Sediment had significantly higher microbial diversity than the rearing water. In sediment, the dominating genus, Sulfurovum and Desulfobulbus, were found to be positively correlated by network analysis, which had similar functionality in sulfur transformation. The relatively higher rates of antibiotic biosynthesis in the FFD sediment might be related to the pathogenic bacteria introduced by the trash fish diet. The difference in microbial community composition and metabolic pathways may be associated with the different pathways for nutrient cycling and animal growth performance. The formulated diet was determined to be more ecologically and economically sustainable than the frozen fish diet for marine IMTA pond systems. Full article

(This article belongs to the Special Issue Agro-Industrial Wastewater Treatment with Decentralized Biological Treatment Methods)

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Graphical abstract

12 pages, 1450 KiB

Open AccessArticle

Second Cheese Whey Treatment Using Zeolite under Continuous Flow Mode and Its Application on Wheat Growth

by Aggelos Kotoulas, Dimitra Agathou, Irene E. Triantaphyllidou, Triantafyllos I. Tatoulis, Christos S. Akratos, Athanasia G. Tekerlekopoulou and Dimitrios V. Vayenas

Water 2019, 11(5), 928; https://doi.org/10.3390/w11050928 - 01 May 2019

Cited by 9 | Viewed by 3151

Abstract

The efficiency of natural zeolite to treat second cheese whey (SCW) and remove ammonium from artificial wastewater (AWW) was examined. Since zeolite has been reported to improve nitrogen availability in soils, its effect on wheat plant growth was also examined. Continuing a previous [...] Read more.

The efficiency of natural zeolite to treat second cheese whey (SCW) and remove ammonium from artificial wastewater (AWW) was examined. Since zeolite has been reported to improve nitrogen availability in soils, its effect on wheat plant growth was also examined. Continuing a previous study using batch reactors, results are presented concerning experiments in fixed-bed columns under continuous operation. Results from the continuous flow column experiments using AWW and zeolite (2.0–2.8 mm) indicated that low flow rates (4 mL/min and 8 mL/min) did not significantly affect zeolite adsorption ability, while maximum zeolite adsorption capacity reached 15.30 mg NH₄⁺-N/g. Finally, the effect of zeolite saturated with NH₄⁺-N on plant growth was examined. The application of saturated zeolite affected significantly wheat plant growth and resulted in faster growth and higher biomass production. Full article

(This article belongs to the Special Issue Agro-Industrial Wastewater Treatment with Decentralized Biological Treatment Methods)

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13 pages, 2432 KiB

Open AccessArticle

Diversity and Biotechnological Potential of Xylan-Degrading Microorganisms from Orange Juice Processing Waste

by Ioanna Zerva, Nikolaos Remmas and Spyridon Ntougias

Water 2019, 11(2), 274; https://doi.org/10.3390/w11020274 - 05 Feb 2019

Cited by 14 | Viewed by 3884

Abstract

The orange juice processing sector produces worldwide massive amounts of waste, which is characterized by high lignin, cellulose and hemicellulose content, and which exceeds 40% of the fruit’s dry weight (d.w.). In this work, the diversity and the biotechnological potential of xylan-degrading microbiota [...] Read more.

The orange juice processing sector produces worldwide massive amounts of waste, which is characterized by high lignin, cellulose and hemicellulose content, and which exceeds 40% of the fruit’s dry weight (d.w.). In this work, the diversity and the biotechnological potential of xylan-degrading microbiota in orange juice processing waste were investigated through the implementation of an enrichment isolation strategy followed by enzyme assays for the determination of xylanolytic activities, and via next generation sequencing for microbial diversity identification. Intracellular rather than extracellular endo-1,4-β-xylanase activities were detected, indicating that peripheral cell-bound (surface) xylanases are involved in xylan hydrolysis by the examined microbial strains. Among the isolated microbial strains, bacterial isolates belonging to Pseudomonas psychrotolerans/P. oryzihabitans spectrum (99.9%/99.8% similarity, respectively) exhibited activities of 280 U/mg protein. In contrast, almost all microbial strains isolated exerted low extracellular 1,4-β-xylosidase activities (<5 U/mg protein), whereas no intracellular 1,4-β-xylosidase activities were detected for any of them. Illumina data showed the dominance of lactic and acetic acid bacteria and of the yeasts Hanseniaspora and Zygosaccharomyces. This is the first report on indigenous xylanolytic microbiota isolated from orange juice processing waste, possessing the biotechnological potential to serve as biocatalysts for citrus biomass valorization through the production of high-added value products and energy recovery. Full article

(This article belongs to the Special Issue Agro-Industrial Wastewater Treatment with Decentralized Biological Treatment Methods)

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23 pages, 2347 KiB

Open AccessArticle

Zeolite as a Potential Medium for Ammonium Recovery and Second Cheese Whey Treatment

by Aggelos Kotoulas, Dimitra Agathou, Irene E. Triantaphyllidou, Triantafyllos I. Tatoulis, Christos S. Akratos, Athanasia G. Tekerlekopoulou and Dimitrios V. Vayenas

Water 2019, 11(1), 136; https://doi.org/10.3390/w11010136 - 14 Jan 2019

Cited by 64 | Viewed by 7064

Abstract

The efficiency of natural zeolite to remove ammonium from artificial wastewater (ammonium aqueous solutions) and to treat second cheese whey was examined, aiming to recover nitrogen nutrients that can be used for further applications, such as slow-release fertilizers. Sorption experiments were performed using [...] Read more.

The efficiency of natural zeolite to remove ammonium from artificial wastewater (ammonium aqueous solutions) and to treat second cheese whey was examined, aiming to recover nitrogen nutrients that can be used for further applications, such as slow-release fertilizers. Sorption experiments were performed using artificial wastewater and zeolite of different granulometries (i.e., 0.71–1.0, 1.8–2.0, 2.0–2.8, 2.8–4.0, and 4.0–5.0 mm). The granulometry of the zeolite had no significant effect on its ability to absorb ammonium. Nevertheless, smaller particles (0.71–1.0 mm) exhibited quicker NH₄⁺-N adsorption rates of up to 93.0% in the first 10 min. Maximum ammonium removal efficiency by the zeolite was achieved at ammonium concentrations ranging from 10 to 80 mg/L. Kinetic experiments revealed that chemisorption is the mechanism behind the adsorption process of ammonium on zeolite, while the Freundlich isotherm model fitted the experimental data well. Column sorption experiments under batch operating mode were performed using artificial wastewater and second cheese whey. Column experiments with artificial wastewater showed high NH₄⁺-N removal rates (over 96% in the first 120 min) for all granulometries and initial NH₄⁺-N concentrations tested (200 and 5000 mg/L). Column experiments with second cheese whey revealed that natural zeolite can remove significant organic loads (up to 40%, 14.53 mg COD/g of zeolite) and NH₄⁺-N (about 99%). For PO₄³⁻-P, the zeolite appeared to saturate after day 1 of the experiments at a removal capacity of 0.15 mg P/g of zeolite. Desorption experiments with water resulted in low NH₄⁺-N and PO₄³⁻-P desorption rates indicating that the zeolite could be used as a substrate for slow nitrogen release in soils. Full article

(This article belongs to the Special Issue Agro-Industrial Wastewater Treatment with Decentralized Biological Treatment Methods)

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25 pages, 1849 KiB

Open AccessArticle

Agroindustrial Wastewater Treatment with Simultaneous Biodiesel Production in Attached Growth Systems Using a Mixed Microbial Culture

by Olga N. Tsolcha, Athanasia G. Tekerlekopoulou, Christos S. Akratos, George Aggelis, Savvas Genitsaris, Maria Moustaka-Gouni and Dimitrios V. Vayenas

Water 2018, 10(11), 1693; https://doi.org/10.3390/w10111693 - 20 Nov 2018

Cited by 37 | Viewed by 4913

Abstract

The use of cyanobacteria in biological wastewater treatment technologies can greatly reduce operation costs by combining wastewater bioremediation and production of lipid suitable as biodiesel feedstock. In this work, an attached growth system was employed to achieve the above-mentioned dual objective using a [...] Read more.

The use of cyanobacteria in biological wastewater treatment technologies can greatly reduce operation costs by combining wastewater bioremediation and production of lipid suitable as biodiesel feedstock. In this work, an attached growth system was employed to achieve the above-mentioned dual objective using a mixed microbial culture dominated by Leptolyngbya and Limnothrix species in diverse heterotrophic consortia. Kinetic experiments on different initial pollutant concentrations were carried out to determine the ability of the established culture to remove organic load (expressed by d-COD, dissolved-Chemical Oxygen Demand), N and P from agroindustrial wastewaters (dairy, winery and raisin). Biomass and oil productivity were determined. It was found that significant removal rates of nutrients were achieved in all the wastewaters examined, especially in that originated from winery in which the highest d-COD removal rate (up to 97.4%) was observed. The attached microbial biomass produced in winery wastewater contained 23.2% lipid/biomass, wt/wt, which was satisfying. The growth in the dairy wastewater yielded the highest attached biomass productivity (5.03 g m⁻² day⁻¹) followed by the mixed effluent of winery-raisin (4.12 g m⁻² day⁻¹) and the winery wastewater (3.08 g m⁻² day⁻¹). The produced microbial lipids contained high percentages of saturated and mono-unsaturated fatty acids (over 89% in total lipids) in all substrates examined. We conclude that the proposed attached growth photobioreactor system can be considered an effective wastewater treatment system that simultaneously produces microbial lipids suitable as biodiesel feedstock. Full article

(This article belongs to the Special Issue Agro-Industrial Wastewater Treatment with Decentralized Biological Treatment Methods)

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11 pages, 1720 KiB

Open AccessArticle

Treatment Efficiency of Diffuse Agricultural Pollution in a Constructed Wetland Impacted by Groundwater Seepage

by Keit Kill, Jaan Pärn, Rauno Lust, Ülo Mander and Kuno Kasak

Water 2018, 10(11), 1601; https://doi.org/10.3390/w10111601 - 08 Nov 2018

Cited by 17 | Viewed by 4037

Abstract

Diffuse agricultural pollution degrades water quality and is one of the main causes of eutrophication; therefore, it is important to reduce it. Constructed wetlands (CW) can be used as an effective measure for water quality improvement. There are two possible ways to establish [...] Read more.

Diffuse agricultural pollution degrades water quality and is one of the main causes of eutrophication; therefore, it is important to reduce it. Constructed wetlands (CW) can be used as an effective measure for water quality improvement. There are two possible ways to establish surface flow CWs, in-stream and off-stream. We studied treatment efficiency of the in-stream free surface flow (FSW) Vända CW in southern Estonia from March 2017 until July 2018. The CW consists of two shallow-water parts planted with cattail (Typha latifolia). According to our analyses, the CW reduced total phosphorus (TP) and phosphate (PO₄-P) by 20.5% and 16.3%, respectively, however, in summer, phosphorus removal was twice as high. We saw significant logarithmic correlation between flow rates and log TP and log PO₄-P removal efficiency (r_s = 0.53, r_s = 0.63, p < 0.01 respectively). Yearly reduction of total organic carbon was 12.4% while total inorganic carbon increased by 9.7% due to groundwater seepage. Groundwater inflow also increased the concentration of total nitrogen in the outlet by 27.7% and nitrate concentration by 31.6%. In-stream FWS CWs are a promising measure to reduce diffuse pollution from agriculture; however, our experience and literature data prove that there are several factors that can influence CWs’ treatment efficiency. Full article

(This article belongs to the Special Issue Agro-Industrial Wastewater Treatment with Decentralized Biological Treatment Methods)

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