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Calabrò PS, Pangallo D, Zema DA. Wastewater treatment in lagoons: A systematic review and a meta-analysis. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 359:120974. [PMID: 38701584 DOI: 10.1016/j.jenvman.2024.120974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 03/22/2024] [Accepted: 04/20/2024] [Indexed: 05/05/2024]
Abstract
This study has carried out a systematic review of 36 scientific papers (reporting 63 case studies) published in the last 15 years about the treatment of industrial, agri-food and municipal wastewater in lagoons. A concentration of studies from a few countries (Italy, Algeria and Iran) and about municipal wastewater (70% of papers) was revealed by the bibliographic analysis. Aeration was supplied in more than 50% of case studies; the storage capacity of lagoons (adopted as a measure of size) was extremely variable (over seven orders of magnitude), while their depth was generally lower than a few metres. The efficiency of lagoon treatments at removing COD was in a wide range (25-98%). Very few studies analysed the energy intensity of treatments in lagoons. The meta-analysis applied to a further selection of 10 papers with 29 case studies revealed significant differences in pH and dissolved oxygen concentration, due to aeration or type of treated wastewater. Treatment efficiency was higher in aerated lagoons compared to non-aerated systems, and did not depend on the type of treated wastewater. Based on the analysis of the reviewed papers, an urgent research need on this topic arises, mainly due to the oldness of most analysed studies. Practical suggestions are given to optimise the depuration performances of lagoons: (i) application of intermittent and night aeration; (ii) reduced air flow rates; (iii) adaptation of microbial biomass to high contents of inhibiting compounds in wastewater; (iv) construction of baffles to keep the planned hydraulic retention time avoiding short-circuit; (v) integration of lagoons with other treatments (e.g., constructed wetlands); (vi) ferti-irrigation of crops with lagoon effluents rather than disposal into water bodies.
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Affiliation(s)
- Paolo S Calabrò
- Mediterranean University of Reggio Calabria, DICEAM Department, Via Graziella, loc. Feo di Vito, I-89122, Reggio Calabria, Italy
| | - Domenica Pangallo
- Mediterranean University of Reggio Calabria, AGRARIA Department, Loc. Feo di Vito, I-89122, Reggio Calabria, Italy
| | - Demetrio Antonio Zema
- Mediterranean University of Reggio Calabria, AGRARIA Department, Loc. Feo di Vito, I-89122, Reggio Calabria, Italy.
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Eddaoukhi A, Berradi M, El Rhayam Y, Rissouli L, El Yacoubi A, Eddaoukhi A, Berradi O, Sallek B, El Bachiri A, Nassali H. Aerated lagoon/adsorption combination method for the treatment of olive mill wastewater: optimizing parameters using study design. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:1111. [PMID: 37646839 DOI: 10.1007/s10661-023-11726-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 08/15/2023] [Indexed: 09/01/2023]
Abstract
The current study focuses on investigating how to improve the efficacy of the combined process of aerated lagooning and adsorption for the treatment of olive mill wastewater (OMWW) from the olive industries in the Loukkos region using the design of experiments approach. The latter made it possible to optimize the experimental conditions, such as the mass concentration of lime, the mass concentration of powdered activated carbon (AC), and the speed of agitation (Va), which are required for the envisaged treatment, in order to control the results after the evaluation of the necessary physicochemical parameters, namely pH, total suspended solids (TSS), chemical oxygen demand (COD), rate of discoloration, and content of polyphenols. The experimental conditions necessary to carry out this study were between 1.4 and 1.75 g/l for AC, between 23 and 32 rpm for the stirring speed, and between 0.88 and 1.3 g/l for the mass concentration of lime. The results of this experiment showed that treating OMWW with the prototype II after adding lime to the mixture resulted in an estimated 85% reduction in the analyzed parameters. The pH, TSS, COD, discoloration rate, and polyphenol content were all reduced from initial values of 4.87, 0.63 (g/l), 80.3 (g (O2/l)), 0.8%, and 1.45 (g/l), respectively, to final values of 6.92, 0.12 (g/l), 12, 0.16%, and 0.25 (g/l). These results are highly significant when compared to those obtained during the treatment of prototype I using only powdered activated carbon, which showed a reduction rate of around 70%.
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Affiliation(s)
- Abdesselam Eddaoukhi
- Laboratory of Advanced Materials and Process Engineering, Department of Chemistry, Faculty of Sciences, Ibn Tofaïl University, P.O. Box 14000, Kenitra, Morocco.
| | - Mohamed Berradi
- Laboratory of Organic Chemistry, Catalysis and Environment, Department of Chemistry, Faculty of Sciences, Ibn Tofaïl University, P.O. Box 14000, Kenitra, Morocco.
| | - Youssef El Rhayam
- Laboratory of Organic Chemistry, Catalysis and Environment, Department of Chemistry, Faculty of Sciences, Ibn Tofaïl University, P.O. Box 14000, Kenitra, Morocco
| | - Lama Rissouli
- Laboratory of Physico-Chemistry Materials, Department of Chemistry, Faculty of Sciences and Techniques, Natural Substances and Environment, Abdel Malek University Essaadi, P.O. Box 416, Tangier, 9000, Morocco
- Laboratory of Pesticide Residues, Unit of Research On Nuclear Techniques, Environment and Quality, Regional Center for Agronomic Research of National Institute for Agronomic Research (INRA), P.O. Box 9010, Tangier, Morocco
| | - Ahmed El Yacoubi
- Laboratory of Advanced Materials and Process Engineering, Department of Chemistry, Faculty of Sciences, Ibn Tofaïl University, P.O. Box 14000, Kenitra, Morocco.
- Laboratory of Chemistry and Environment, Chemistry of Solid Minerals, Faculty of Sciences, Mohamed First University, P.O. Box 524, Oujda, 60000, Morocco.
| | - Abdessamad Eddaoukhi
- Laboratory of Research in Informatics, Department of Informatics, Faculty of Sciences, Ibn Tofaïl University, P.O. Box 14000, Kenitra, Morocco
| | - Omar Berradi
- Laboratory of Organic Chemistry, Catalysis and Environment, Department of Chemistry, Faculty of Sciences, Ibn Tofaïl University, P.O. Box 14000, Kenitra, Morocco
| | - Brahim Sallek
- Laboratory of Advanced Materials and Process Engineering, Department of Chemistry, Faculty of Sciences, Ibn Tofaïl University, P.O. Box 14000, Kenitra, Morocco
| | - Abderrahim El Bachiri
- University Department, Royal Naval School of Marine Engineering, Boulevard Sour-Jdid, P.O. Box 16314, Casablanca, 20052, Morocco
| | - Hakima Nassali
- Laboratory of Advanced Materials and Process Engineering, Department of Chemistry, Faculty of Sciences, Ibn Tofaïl University, P.O. Box 14000, Kenitra, Morocco
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Effects of Black Liquor Shocks on the Stability of Activated Sludge Treatment of Kraft Pulp Mill Effluent: Morphological Alteration in Daphnia magna and Mutagenicity and Genotoxicity Response in Salmonella typhimurium. SUSTAINABILITY 2022. [DOI: 10.3390/su14073869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
The objective of this study is to evaluate the stability of activated sludge (AS) in the treatment of kraft pulp mill effluent exposed to black liquor shock, as well as the effect of its exposure on the morphology of Daphnia magna and DNA damage through mutagenicity and genotoxicity response in Salmonella typhimurium. To this end, we applied doses of 2-, 4-, 10-, and 30-mL black liquor/L influent—shock 1 (S1), shock 2 (S2), shock 3 (S3), and shock 4 (S4), respectively—to kraft pulp mill effluent. The system stability was checked by analyzing heterotrophic biomass activity and discharge quality, evaluated using Ames test and Daphnia magna. The results show that the chemical oxygen demand (COD) removal efficiency for normal conditions was 64.84%, falling to 61.68%, and 61.31% for S1 and S2, respectively, and values of 52.11% for S3 and 20.34% for S4. The biomass activity decreased after each shock was applied, but then recovered. There was no evidence of lethal toxicity (LC50) to Daphnia magna at any of the concentrations. Therefore, it is feasible to apply doses S1 and S2 to an AS system that treats kraft pulp mill effluent.
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Orrego R, Guchardi J, Beyger L, Barra R, Hewitt LM, Holdway D. Sex-Related Embryotoxicity of Pulp Mill Effluent Extracts in Medaka (Oryzias latipes) Female Leucophore-free FLFII Strain. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2021; 40:2297-2305. [PMID: 33978263 DOI: 10.1002/etc.5115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/06/2021] [Accepted: 05/06/2021] [Indexed: 06/12/2023]
Abstract
The aim of the present study was to evaluate the effects of exposure to Chilean pulp mill effluent extracts on developing postfertilized medaka embryos before and after sex definition relative to sex steroids (testosterone and 17beta-estradiol) and a wood phytoestrogen (beta-sitosterol). Our study included 2 waterborne semichronic exposure experiments, using a 24-h post fertilization (hpf) unknown-sex FLFII (female leucophore free) group and a second 72-hpf FLFII phenotypic sex-identified group (male autofluorescence leucophore) strain of medaka embryos. Chronic exposure of both FLFII strain embryo groups showed similar delay in time to hatch and decreased hatchability. Teratogenic responses such as vertebral malformation (fusion, incomplete formation, and lack of vertebral formation process) and pericardial edema were observed in both experiments, with a high percentage related to FLFII fluorescent leucophore-identified males. In addition, high mortality associated with severe malformations was observed in male and female embryos exposed to testosterone. Our research has demonstrated that exposure to Chilean mill effluent extracts caused severe male medaka embryotoxicity (in postfertilized embryos) before and after sex definition and, irrespective of the experimental group and effluent treatment, suggests partial removal following secondary treatment. Furthermore, differences in the severity and type of teratogenic effects with previous experiments (d-rR medaka strain), are associated with the unique phenotypes of this medaka mutant strain. Environ Toxicol Chem 2021;40:2297-2305. © 2021 SETAC.
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Affiliation(s)
- Rodrigo Orrego
- Aquatic Toxicology Laboratory, Faculty of Marine Sciences and Biological Resources, Natural Science Institute Alexander von Humboldt, University of Antofagasta, Antofagasta, Chile
- Aquatic Toxicology Laboratory, Faculty of Science, Ontario Tech University, Oshawa, Ontario, Canada
| | - John Guchardi
- Aquatic Toxicology Laboratory, Faculty of Science, Ontario Tech University, Oshawa, Ontario, Canada
| | - Lindsay Beyger
- Aquatic Toxicology Laboratory, Faculty of Science, Ontario Tech University, Oshawa, Ontario, Canada
| | - Ricardo Barra
- Department of Aquatic Systems, Faculty of Environmental Sciences and EULA-Chile Centre, University of Concepción, Concepción, Chile
| | - L Mark Hewitt
- Environment and Climate Change Canada, Burlington, Ontario, Canada
| | - Douglas Holdway
- Aquatic Toxicology Laboratory, Faculty of Science, Ontario Tech University, Oshawa, Ontario, Canada
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Davarazar M, Kamali M, Lopes I. Engineered nanomaterials for (waste)water treatment - A scientometric assessment and sustainability aspects. NANOIMPACT 2021; 22:100316. [PMID: 35559973 DOI: 10.1016/j.impact.2021.100316] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 04/07/2021] [Accepted: 04/07/2021] [Indexed: 06/15/2023]
Abstract
Application of nanomaterials for the treatment of effluents originated from various industrial and non-industrial sources, has been rapidly developed in recent decades. In this situation, there is a need for conclusive studies to identify the current status of the knowledge in this field and to promote the commercialization of such technologies by providing recommendations for future studies. In the present manuscript, a scientometric assessment on the progress made in this field has been performed and the results have been organized and discussed in terms of science statistics, research hotspots and trends, as well as the relevant sustainability aspects. Based on a set of keywords, identified through a pre-literature analysis, a total of 6539 documents were retrieved from the Web of Science (WoS) database and analyzed to achieve the main goals of this study. The results demonstrate that the studies in this field have been initiated since the beginning of the 2000s but were mainly performed in lab and pilot scales. Also, China and Iran were identified as the most contributing countries in this scientific area in terms of the number of publications. Among various types of engineered nanomaterials (ENMs), there has been especial attention for the application of iron-based nanomaterials as well as carbonaceous structures (such as graphene oxide and biochar). Besides, there are not still strong collaborations formed among researchers in this area worldwide. Regarding the research hotspots, the synthesis of green and sustainable nanomaterials (e.g., biosynthesis approaches) has received attention in recent years. The results can also demonstrate that the most widely studied pathway for the removal of pollutants from (waste)waters involves the adsorption of the pollutants using ENMs. Treatment of contaminants of emerging concern (CECs) as well as exploring the mechanisms involved in the treatment of contaminated (waste)waters using ENMs and the possible by-products are considered the current trends in the literature. Regarding the sustainability aspects of ENMs for (waste)water treatment, the results achieved in this study calls for in-depth sustainability studies, which consider parameters such as economic, environmental, and social aspects of nanomaterials utilization for (waste)water treatment purposes, besides the technical parameters, to push transferring such technologies from lab and pilot scales to large and real-scale applications.
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Affiliation(s)
- Mahsa Davarazar
- Department of Biology, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - Mohammadreza Kamali
- Process and Environmental Technology Lab, Department of Chemical Engineering, KU Leuven, 2860 Sint-Katelijne-Waver, Belgium; CESAM - Center of Environmental and Marine Studies & Department of Biology, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
| | - Isabel Lopes
- Department of Biology, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal; CESAM - Center of Environmental and Marine Studies & Department of Biology, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
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Gómez G, Salinas M, Ruiz-Tagle N, Sossa K, Vidal G. Molecular weight distribution of the recalcitrant organic matter contained in kraft mill effluents and the identification of microbial consortia responsible for an anaerobic biodegradable fraction. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2019; 55:281-291. [PMID: 31698987 DOI: 10.1080/10934529.2019.1688019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/19/2019] [Accepted: 10/25/2019] [Indexed: 06/10/2023]
Abstract
The objective of this research was to evaluate the distribution of the molecular weights of the recalcitrant organic matter contained in kraft mill effluents and identify microbial consortia responsible for an anaerobic biodegradable fraction. As a result, the average removal efficiencies of chemical organic demand (COD) and biological oxygen demand (BOD5) during the entire period of operation were 28% and 53%, respectively. The non-biodegradable organic matter was detected at molecular weights less than 1000 Da. However, most of the organic matter was in the molecular weight fraction higher than 10000 Da with 32 ± 11.6% COD as well as color (42.3 ± 8.7%), total phenolic compounds (35.9 ± 7.9%) and adsorbable organic compounds (AOX) (13.0 ± 2.7%). Methanogenic acetoclastic archaea of the genera Methanomethylovorans and Methanosarcina were found in the surface and middle zones of the reactor. Moreover, Methanosaeta and Methanolinea were identified in the low zone of the reactor. In all zones of the reactor, Desulfomicrobium and Desulfovibrio were found to be the most dominant genera of sulfate-reducing bacteria (SRB).
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Affiliation(s)
- Gloria Gómez
- Engineering and Biotechnology Environmental Group, Environmental Science Faculty & Center EULA-Chile, University of Concepción, Concepción, Chile
| | - Miguel Salinas
- Area Servicios Nueva Aldea, Wood Pulp & Energy, Celulosa Arauco y Constitución S.A, Nueva Aldea, Chile
| | - Nathaly Ruiz-Tagle
- Biofilm Laboratory and Environmental Microbiology, Biotechnology Center, University of Concepción, Concepción, Chile
| | - Katherine Sossa
- Biofilm Laboratory and Environmental Microbiology, Biotechnology Center, University of Concepción, Concepción, Chile
| | - Gladys Vidal
- Engineering and Biotechnology Environmental Group, Environmental Science Faculty & Center EULA-Chile, University of Concepción, Concepción, Chile
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Chamorro S, Vergara JP, Jarpa M, Hernandez V, Becerra J, Vidal G. Removal of stigmasterol from Kraft mill effluent by aerobic biological treatment with steroidal metabolite detection. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2016; 51:1012-1017. [PMID: 27399163 DOI: 10.1080/10934529.2016.1198190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Stigmasterol is a phytosterol contained in Kraft mill effluent that is able to increase over 100% after aerobic biological treatment. This compound can act as an endocrine disrupter as its structure is similar to that of cholesterol. The aim of this study was to evaluate the removal of stigmasterol from Kraft mill effluents treated by a moving bed biofilm reactor (MBBR) with steroidal metabolite detection. The MBBR was operated for 145 days, with a hydraulic retention time of 2 days. Stigmasterol and steroidal metabolites were detected by gas chromatography with a flame ionization detector during MBBR operation. The results show that the MBBR removed 87.4% of biological oxygen demand (BOD5), 61.5% of chemical oxygen demand (COD), 24.5% of phenol and 31.5% of lignin, expressed in average values. The MBBR system successfully removed 100% of the stigmasterol contained in the influent (33 µg L(-1)) after 5 weeks of operation. In that case, the organic load rate was 0.343 kg COD m(-3) d(-1). Furthermore, different steroidal compounds (e.g., testosterone propionate, stigmast-4-en-3-one, 5α-pregnan-12-one-20α-hydroxy, 5α-pregnane-3,11,20-trione and 3α-hydroxy-5α-androstane-11,17-dione were detected in the Kraft mill effluent as potential products of phytosterol biotransformation.
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Affiliation(s)
- Soledad Chamorro
- a Engineering and Environmental Biotechnology Group, Environmental Science Faculty and EULA-Chile Center, University of Concepción , Concepción , Chile
| | - Juan P Vergara
- a Engineering and Environmental Biotechnology Group, Environmental Science Faculty and EULA-Chile Center, University of Concepción , Concepción , Chile
| | - Mayra Jarpa
- a Engineering and Environmental Biotechnology Group, Environmental Science Faculty and EULA-Chile Center, University of Concepción , Concepción , Chile
| | - Victor Hernandez
- b Natural Products Chemistry Laboratory, Faculty of Natural and Oceanographic Sciences, University of Concepción , Concepción , Chile
| | - Jose Becerra
- b Natural Products Chemistry Laboratory, Faculty of Natural and Oceanographic Sciences, University of Concepción , Concepción , Chile
| | - Gladys Vidal
- a Engineering and Environmental Biotechnology Group, Environmental Science Faculty and EULA-Chile Center, University of Concepción , Concepción , Chile
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Dykstra CM, Giles HD, Banerjee S, Pavlostathis SG. Fate and biotransformation of phytosterols during treatment of pulp and paper wastewater in a simulated aerated stabilization basin. WATER RESEARCH 2015; 68:589-600. [PMID: 25462765 DOI: 10.1016/j.watres.2014.10.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 10/09/2014] [Accepted: 10/13/2014] [Indexed: 06/04/2023]
Abstract
Pulp and paper wastewater (PPW) contains significant concentrations of phytosterols, suspected of inducing endocrine disruption in aquatic species. Aerated stabilization basins (ASBs) are commonly used for the treatment of PPW, but phytosterol removal varies among treatment systems. The objective of this study was to better understand the removal processes and biotransformation of phytosterols within an ASB treatment system fed with untreated PPW. PPW settled solids and supernatant fractions showed that phytosterols are primarily associated with settleable solids, which carry phytosterols to ASB sediment where anoxic/anaerobic conditions prevail. Bioassays with supernatant and settled PPW fractions of the raw wastewater conducted under aerobic and anaerobic conditions, respectively, showed that solids disintegration and hydrolysis results in phytosterol release in ASBs. A simulated ASB, fed with PPW and operated for 2.4 years at three hydraulic retention times (HRTs; 22.2, 11.1 and 5.6 d) with total phytosterol and solids loading rates from 10 to 42 μg/L-d and 44-178 mg/L-d, respectively, was used to determine the steady-state effluent quality and sediment characteristics. Although effluent COD and phytosterol concentrations were relatively low and stable (84-88% total COD removal; 82-94% total phytosterol removal) across the range of HRTs tested, sediment COD and phytosterol concentrations increased with increasing loading rate. On average, 51% of the phytosterols entering the ASB were removed via biotransformation, 40% were retained in the sediment, and the remaining 9% exited with the effluent. This study demonstrates the role of sediment as a source of phytosterol release in ASBs and highlights the importance of HRT and the PPW characteristics for predicting phytosterol fate in ASBs.
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Affiliation(s)
- Christy M Dykstra
- School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0512, USA
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Dykstra CM, Giles HD, Banerjee S, Pavlostathis SG. Biotransformation of phytosterols under aerobic conditions. WATER RESEARCH 2014; 58:71-81. [PMID: 24747138 DOI: 10.1016/j.watres.2014.03.062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 03/19/2014] [Accepted: 03/24/2014] [Indexed: 06/03/2023]
Abstract
Phytosterols are plant-derived sterols present in pulp and paper wastewater and have been implicated in the endocrine disruption of aquatic species. Bioassays were performed to assess the effect of an additional carbon source and/or solubilizing agent on the aerobic biotransformation of a mixture of three common phytosterols (β-sitosterol, stigmasterol and campesterol). The aerobic biotransformation of the phytosterol mixture by a mixed culture developed from a pulp and paper wastewater treatment system was examined under three separate conditions: with phytosterols as the sole added carbon source, with phytosterols and dextrin as an additional carbon source, and with phytosterols added with ethanol as an additional carbon source and solubilizing agent. Significant phytosterol removal was not observed in assays set up with phytosterol powder, either with or without an additional carbon source. In contrast, all three phytosterols were aerobically degraded when added as a dissolved solution in ethanol. Thus, under the experimental conditions of this study, the bioavailability of phytosterols was limited without the presence of a solubilizing agent. The total phytosterol removal rate was linear for the first six days before re-spiking, with a rate of 0.47 mg/L-d (R(2) = 0.998). After the second spiking, the total phytosterol removal rate was linear for seven days, with a rate of 0.32 mg/L-d (R(2) = 0.968). Following the 7th day, the phytosterol removal rate markedly accelerated, suggesting two different mechanisms are involved in phytosterol biotransformation, more likely related to the production of enzyme(s) involved in phytosterol degradation, induced under different cell growth conditions. β-sitosterol was preferentially degraded, as compared to stigmasterol and campesterol, although all three phytosterols fell below detection limits by the 24th day of incubation.
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Affiliation(s)
- Christy M Dykstra
- School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0512, USA
| | - Hamilton D Giles
- School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0512, USA
| | - Sujit Banerjee
- School of Chemical and Biomolecular Engineering, Institute of Paper Science and Technology, Georgia Institute of Technology, 500 10th Street, N.W., Atlanta, GA 30318, USA
| | - Spyros G Pavlostathis
- School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0512, USA.
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