Effects of Physicochemical and Biological Treatment on Structure, Functional and Prebiotic Properties of Dietary Fiber from Corn Straw.

Corn straw is one kind of agricultural by-product containing 70-80% insoluble dietary fiber (IDF). In order to develop corn straw dietary fiber, this study was conducted to increase soluble dietary fiber (SDF) yield and improve the structure, functional and prebiotic properties of IDF and SDF from corn straw treated by alkali oxidation treatment, enzymatic hydrolysis, microbial fermentation and the combination of these methods. The results demonstrated that the yield of SDF was significantly increased from 2.64% to 17.15% after corn straw was treated by alkali oxidation treatment + Aspergillus niger fermentation + cellulase hydrolysis, compared with untreated corn straw. The SDF extracted from corn straw treated by alkali oxidation treatment + Aspergillus niger fermentation + cellulase hydrolysis (F-SDF) exhibited a honeycomb structure, low crystallinity (11.97%), good antioxidant capacity and high capacities of water holding, water solubility and cholesterol absorption and promoted short-chain fatty acids production by chicken cecal microbial fermentation in vitro. F-SDF enhanced the antibacterial activity against Escherichia coli and Staphylococcus aureus proliferations of Lactobacillus plantarum when it was used as a substrate for Lactobacillus plantarum fermentation. It could be concluded that the combined treatments could increase SDF yield from corn straw and improve its functional and prebiotic properties.

Comparative evaluation between Taguchi method and response surface method for optimization of electrocoagulation process in the context of treatment of dairy industry wastewater.

The presence of a large amount of organic and inorganic pollutants in dairy effluent is a substantial environmental issue. This study investigated electrocoagulation (EC) as a potential treatment method for dairy wastewater under different operating conditions, such as applied voltage (5-25 V), electrolysis time (30-90 min), and inter-electrode distance (1-2 cm) by using aluminum electrodes. This study focuses on achieving the maximum removal of BOD, COD, and nitrate in dairy effluents with the aforementioned operating conditions. The process was optimized using the response surface methodology (RSM) and Taguchi method. RSM method optimized the electrocoagulation operating conditions such as the voltage at 23.75 V, time of 90 min, and inter-electrode distance at 1.07 cm. This optimization achieved the maximum removal percentage of BOD, COD, and nitrate at 79.06%, 84.35%, and 79.64%, respectively, in dairy effluent. Taguchi method optimized the electrocoagulation parameters such as the voltage at 25 V, time duration of 90 min, and inter-electrode distance of 1.00 cm, showcasing improved removal percentages of BOD, COD, and nitrate as 90.54%, 89.28%, and 82.74% respectively. The current study attempts to understand the optimization efficiencies between Taguchi method and response surface method for diary wastewater treatment.

Geochemistry and the optics of geospatial analysis as a preposition of water quality on a macroscale.

The water treatment depends exclusively on the identification of residues containing toxic chemical elements accumulated in NPs (nanoparticles), and ultrafine particles sourced from waste piles located at old, abandoned sulfuric acid factories containing phosphogypsum requires global attention. The general objective of this study is to quantify and analyze the hazardous chemical elements present in the leachate of waste from deactivated sulfuric acid factories, coupled in NPs and ultrafine particles, in the port region of the city of Imbituba, Santa Catarina, Brazil. Samples were collected in 2020, 2021, and 2022. Corresponding images from the Sentinel-3B OLCI satellite, taken in the same general vicinity, detected the levels of absorption coefficient of Detritus and Gelbstoff (ADG443_NN) in 443 m-1, chlorophyll-a (CHL_NN (m-3)), and total suspended matter (TSM_NN (g m-3) at 72 points on the marine coast of the port region. The results of inductively coupled plasma atomic-emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) demonstrate that the leaching occurring in waste piles at the port area of Imbituba was the likely source of hazardous chemical elements (e.g., Mg, Sr, Nd, and Pr) in the environment. These leachates were formed due to the presence of coal pyrite and Fe-acid sulfates in said waste piles. The mobility of hazardous chemical elements potentiates changes in the marine ecosystem, in relation to ADG443_NN (m-1), CHL_NN (m-3), and TSM NN (g m-3), with values greater than 20 g m-3 found in 2021 and 2022. This indicated changes in the natural conditions of the marine ecosystem up to 30 km from the coast in the Atlantic Ocean, justifying public initiatives for water treatment on a global scale.

Emergence of per- and poly-fluoroalkyl substances (PFAS) and advances in the remediation strategies.

A group of fluorinated organic molecules known as per- and poly-fluoroalkyl substances (PFAS) have been commonly produced and circulated in the environment. PFAS, owing to multiple strong CF bonds, exhibit exceptional stability and possess a high level of resistance against biological or chemical degradation. Recently, PFAS have been identified to cause numerous hazardous effects on the biotic ecosystem. As a result, extensive efforts have been made in recent years to develop effective methods to remove PFAS. Adsorption, filtration, heat treatment, chemical oxidation/reduction, and soil washing are a few of the physicochemical techniques that have shown their ability to remove PFAS from contaminated matrixes. However these methods also carry significant drawbacks, including the fact that they are expensive, energy-intensive, unsuitable for in-situ treatment, and requirement to be carried under dormant conditions. The metabolic products released upon PFAS degradation are largely unknown, despite the fact that thermal disintegration methods are widely used. In contrast to physical and chemical methods, biological degradation of PFAS has been regarded as efficient method. However, PFAS are difficult to instantly and completely metabolize through biological methods due to the limitations of biocatalytic mechanisms. Nevertheless, cost, easy-to-operate and environmentally safe are some of the advantages over its counterpart. The present review comprehensively discusses the occurrence of PFAS, the state-of-the science of remediation technologies and approaches applied, and the remediation challenges. The article also focuses on the future research directions toward the development of effective methods for PFAS-contaminated site in-situ treatment.

A critical review of textile industry wastewater: green technologies for the removal of indigo dyes.

The denim textile industry represents an important productive sector. It generates wastewater with low biodegradability due to the presence of persistent pollutants, which can produce toxic and carcinogenic compounds; therefore, wastewater treatment reduces risks to aquatic life and public health. This paper presents a review of 172 papers regarding textile industry wastewater treatment for the removal of contaminants, especially indigo dyes used in the denim industry, in the context of green technologies. The physicochemical characteristics of textile wastewater, its environmental and health impacts, and the permissible limit regulations in different countries were reviewed. Biological, physicochemical and advanced oxidation processes for the removal of indigo dyes were reviewed. The goal of this study was to analyze the characteristics of green technologies; however, the research does not clearly demonstrate an effect on energy consumption savings, carbon footprint decreases, and/or waste generation. Advanced oxidation processes showed the highest color removal efficiency (95 and 97% in synthetic or real wastewater, respectively). Photocatalysis and Fenton reactions were the most efficient processes. None of the revised works presented results regarding upscaling for industrial application, and the results should be discussed in terms of the guidelines and maximum permissible limits established by international legislation. New technologies need to be developed and evaluated in a sustainable context with real wastewater.

Current available treatment technologies for saline wastewater and land-based treatment as an emerging environment-friendly technology: A review.

Different industrial activities such as agro-food processing and manufacturing, leather manufacturing, and paper and pulp production generate highly saline wastewater. Direct discharge of saline wastewater has resulted in pollution of waterbodies by very high magnitudes. Consequently, an enormous number of pollutants such as heavy metals, salts, and organic matter are also released into the environment threatening the survival of human and biota. Saline wastewater also has significant effects on survival of plants, agricultural activities, and groundwater systems. Several treatments and disposal technologies are available for saline wastewater, but the selection of the most appropriate treatment and disposal technology still remains a major challenge with respect to the economic or technical constraints. Considering the sustainable management of saline wastewater, the present review is an attempt to compile the existing and emerging technologies for the treatment of saline wastewater. Among all the individual and hybrid technologies, land-based treatment systems are proven to be the most efficient technologies considering the energy demands, economic, and treatment efficiencies. Likewise, new and sustainable technologies are the need of hour integrating both the treatment and management and the resource recovery factors along with the ultimate goal of the protection in terms of human health and environmental aspect. PRACTITIONER POINTS: Physico-chemical treatment technologies for saline wastewater. Combined/Hybrid technologies for the treatment of saline wastewater. Land-based treatments as the environment friendly and sustainable method for saline wastewater treatment and disposal. Role of phytoremediation in land-based treatment.

Physical-chemical pre-treatment of sanitary landfill raw leachate by direct ascending filtration.

Several environmental problems in Brazil are caused by the accelerated urban and industrial growth and by the multiplicity of urban waste generated. Waste disposal in landfills is still common practice in Brazil. This work was conducted in sand filters and activated carbon column, proposing an alternative for the physical-chemical treatment of leachate as a pre-treatment to preserve the biological process. The results showed reductions of up to 74% for COD, 47% for BOD5, 93% for color, 90% for ammonia and an increase from 0.3 to 0.9 in the BOD5/COD ratio. Although the results obtained do not fall within the limits of the legislation, the results for ammonia concentration was reduced by 33.25% and 85.37% after filtration and activated carbon column treatment respectively. The use of activated carbon columns resulted in an excellent performance in the reduction of heavy metals in the leachate. The performance demonstrated a removal of 60-96%. Limitations were found in the length of the filtration races, as a limiting factor in the process. The results show the potential of using direct upward filtration with sand and activated carbon filters for the treatment of landfill leachate.

Avaliação do crescimento de micro-organismos fotossintetizantes em fotobiorreator tubular empregando nutrientes provenientes da vinhaça tratada / Evaluation of the growth of photosynthetic microorganisms in tubular photobioreactor using nutrients from treated vinasse

vinhaça é resultante da produção de álcool, após a fermentação do mosto e destilação do vinho. É um resíduo rico em nutrientes, principalmente matéria orgânica, nitrogênio, fósforo e potássio. Para ser despejado em rios e lagos, esse efluente deve passar por tratamentos para remoção desses nutrientes, pois o excesso desses elementos nos corpos hídricos poderia levar a grandes problemas ambientais, de modo que tem sido utilizado em fertirrigação. Microorganismos fotossintetizantes absorvem nutrientes inorgânicos, podendo absorver nutrientes de águas residuais. Se for removida a parte orgânica da vinhaça, a fração inorgânica ou com baixa carga orgânica pode ser a base ou o próprio meio de cultivo destes micro-organismos, que absorvem gás carbônico e sua biomassa é de interesse industrial. Neste contexto, foi estudado o cultivo de Monoraphidium contortum e Synechocystis salina, oriundos de água de mangue, em frascos de Erlenmeyer e em fotobiorreatores tubulares por processo descontínuo, empregando a vinhaça proveniente do tratamento aeróbio (biológico), acoplada a processos físico-químicos, com diferentes diluições. As características físico-químicas das vinhaças tratadas foram avaliadas. Além disso, foram comparados os crescimentos celulares nas diferentes condições experimentais adotadas para o crescimento da microalga M. contortum e da cianobactéria S. salina na vinhaça tratada com e sem diluição. Em cultivos em frascos de Erlenmeyer, em meio proveniente de tratamento biológico, o crescimento celular não diferiu do cultivo em meio padrão, com diluições de 5 e 2 vezes da vinhaça tratada para M. contortum e S. salina, respectivamente. Em fotobiorreator tubular, independente do tratamento ser apenas biológico ou também com carvão ativado, as concentrações celulares máximas (Xm) de M. contortum e S. salina foram da ordem de 1,86x107 células mL-1 e 7,90x106 células mL-1, respectivamente, valores esses menores que os obtidos em meio padrão, com valores de Xm de 2,69x107 células mL-1 e 1,27x106 células mL-1 para M. contortum e S. salina, respectivamente. Em fotobiorreatores tubulares, os teores de mínimos de lipídios de M. contortum e S. salina foram de 33,4 % e 11,0 %, respectivamente. Adicionalmente, os teores mínimos de proteínas da microalga foram de 15,1 % e da cianobactéria foi de 23,2 %

The vinasse is the result of the production of alcohol after the fermentation of the mash and the distillation of the wine. It is a waste rich in nutrients, mainly organic matter, nitrogen, phosphorus and potassium. To be discharged into rivers and lakes, this effluent must be treated in order to remove nutrients, because the excess of these elements in water bodies can lead to major environmental problems, so that it has been used in fertigation. Photosynthetic microorganisms absorb inorganic nutrients and they can absorb nutrients from wastewater. If the organic fraction of vinasse is removed, the inorganic or low organic fraction may be the basis or a medium of cultivation of these microorganisms, which absorb carbon dioxide and its biomass is of industrial interest. In this context, Monoraphidium contortum and Synechocystis salina from mangrove water were cultivated in Erlenmeyer flasks and in tubular photobioreactors by batch process using vinasse from aerobic biological treatment, coupled to physicochemical treatments with different dilutions. The physicochemical characteristics of the treated vinasse were evaluated. In addition, cell growth was compared under different experimental conditions adopted for growth of microalgae M. contortum and cyanobacteria S. salina in vinasse treated with and without dilution. In Erlenmeyer flask cultivations, in medium from the biological treatment, the cell growth was not different of that one in standard medium cultivation, with dilutions of 5 and 2 times the vinasse treated for M. contortum and S. salina, respectively. In the tubular photobioreactor, irrespective if the treatment is only biological or also is carried out treatment with activated charcoal, they were obtained maximum cell concentrations (Xm) of M. contortum and S. salina of 1.86x107 cells mL-1 and 7.90x106 cells. mL-1 , respectively, lower than the standard, whose Xm values were 2.69x107 cells mL-1 and 1.27x106 cells mL-1 for M. contortum and S. salina, respectively. In tubular photobioreactors, the minimum lipid contents of M. contortum and S. salina were 33.4 % and 11.0 %, respectively. In addition, the minimum protein content of microalgae was 15.1 % and cyanobacterium was 23.2 %

Treatment of petrochemical wastewater and produced water from oil and gas.

Wastewater in petrochemical processes and produced water from oil and gas production remain a challenge for the industry to minimize their impact on the environment. Recent research and development of treatment technologies for petrochemical wastewater and produced water from oil and gas industries published in 2018 were summarized in this annual review. Great efforts and progresses were made in various treatment options, including membrane processes, advanced oxidation, biological systems, adsorption, coagulation, and combined processes. PRACTITIONER POINTS: Treatment technologies for petrochemical wastewater are reviewed. Research development in produced water from oil and gas industries is summarized. Reviewed technologies include traditional, advanced, and innovative processes.

Removal of inorganic chemical species and organic matter from slaughterhouse wastewater via calcium acetate synthesized from eggshell.

The physicochemical treatment (PT) of slaughterhouse wastewater (SWW) was investigated. In the first stage, calcium acetate (Ca(Ac)2) was synthesized in five different ways: (1) acetic acid (HAc) and chicken eggshell (CaAc1), (2) lime (CaAc2), (3) a 1:1 eggshell and lime mixture (CaAc3), (4) a 1:2 eggshell and lime mixture (CaAc4), and (5) calcium oxide via the calcination of eggshell (CaAc5). The synthesized Ca(Ac)2 samples were characterized by IR, SEM, XRD, and EDS. Subsequently, the samples were used to precipitate oxyanions and organic matter. The experiments were carried out at pH 4 and 12. For the treatment with CaAc1 at pH 4, an acid (HCl, H2SO4, or HAc) was also added. The best results for CaAc1 in acid media were attained with HCl, where removal efficiencies of 82.23% total suspended solids, 76% turbidity, 81.43% color, 53.86% Fe, 69.74% Cu, and 14.64% Na were observed. This treatment also removed ∼99% fecal and total coliforms, 26.49% COD, and 78.39% TOC. The experiments were also performed at pH 12 using CaAc1. These afforded removal efficiencies of 92.7% turbidity, 84.7% color, 40.5% phosphates (PO43-), and 64.7% sulfates (SO42-). In addition, this method removed metals, 35.37% COD and 99% fecal and total coliforms.