Potential Of Wastewater Research Articles

The phagotrophic growth of algae on bacteria and its potential for wastewater and waste sludge treatment

Algae exhibit diverse growth strategies, including phototrophy, osmotrophy, and phagotrophy. While phototrophic and osmotrophic growths have been extensively studied, phagotrophic growth remains relatively unexplored. This research delves into the phagotrophic growth of Ochromonas danica on bacteria, evaluating its potential for wastewater and waste sludge treatment. The study reveals that O. danica was able to grow on bacteria without light or additional nutrients, achieving a doubling time of 3.5–3.9 hours and converting 41–45 % of bacterial organic matter into algal biomass. The resultant O. danica cells were lipid-rich, containing 35–46 % lipids by dry weight. The efficiency of O. danica in treating waste sludge was highlighted, achieving a 43 % reduction in organic matter within 36 hours, outperforming conventional aerobic digestion. The study also highlights the potential of O. danica in wastewater treatment. An approach was developed to reclaim organic matter from wastewater through a two-stage process, in which bacteria were first grown on wastewater organic matter and then the grown bacteria were fed to O. danica for growth. Results show that a total of 78.2 % of the initial wastewater organic matter was removed through this approach and 27.3 % of the removed organic matter was converted into lipid-rich algal biomass. The findings underscore the potential of phagotrophic growth for waste treatment and lipid production. The simplicity of the phagotrophic process, independent of light or complex nutrient supplementation, positions it as a promising strategy for industrial applications in waste sludge and wastewater treatment.

Algal consortia as the flexible bio-system for wastewater treatment: Effect of different light intensities on photosynthetic performance, anti-oxidative system and biodiesel production of consortia

Competence of microalgae consortia-1 (Chlorococcum humicola and Tetradesmus sp.) and consortia-2 (Chlorococcum humicola, Scenedesmus vacuolatus and Tetradesmus sp.) was analyzed by examining their adaptability potential in wastewater under different light intensities (20 W/m2 and 40 W/m2). The results depicted highest decline in nutrients and metal concentration (40–90%) at light intensity of 40 W/m2 by consortia-1 and consortia-2 treated with wastewater (50%, 100%). The result of metal remediation was further confirmed by fourier transform infrared spectroscopy (FTIR) which reflected occurrence of different functional groups in selected consortia. Moreover, light intensity of 40 W/m2 induced neutral-lipid accumulation (1750 cm−1) in consortia-1 as depicted in FTIR spectra. The maximum active photosystem-II reaction center (79.75%), quantum yield (26.17%) and performance index (195.8%) revealed that light intensity (40 W/m2) and wastewater augmented functioning of photosystem-II in consortia-1 than consortia-2. Further, consortia-2 appeared more sensitive to oxidative stress as the concentration of oxidative stress markers (5.73–6.39 folds) was amplified after treatment with wastewater at light intensity of 40 W/m2. The prodigious tolerance potential towards different light intensities and wastewater concentration of consortia-1 may be attributed to increased activity of ascorbic acid (1.16 folds), proline (1.32 folds), cysteine (2.80 folds), superoxide dismutase (3.44 folds), catalase (2.52 folds) and glutathione reductase (1.90 folds). However, abundance of saturated fatty acid (41.34%) together with high cetane number (59.07) indicated that consortia 2 can produce excellent quality biofuel at 20 W/m2 while consortia-2 at 40 W/m2. Overall, consortia 1 appeared competent in terms of photosynthetic performance, remediation efficiency and antioxidant defense mechanism under 20 W/m2 and 40 W/m2 while consortia-2 showed quality biodiesel production at 20 W/m2. Thus, algal consortia based on photosynthetic performance and defense responses along with excellent biodiesel quality under different light intensity and wastewater concentration can serve as the promising biosystem for biomass and bioenergy production.

Elucidating the role of ferric chloride on carbon capture from low-strength municipal wastewater in high-rate activated sludge process: Parameter optimization and crucial mechanism

To enhance organics capture efficiency from low-strength municipal wastewater of China, FeCl3 enhanced high-rate activated sludge (FC-HRAS) process was established in this work. Effects of sludge concentration and FeCl3 dosage on carbon capture in FC-HRAS were investigated. The optimum sludge concentration of 2.0 g/L and FeCl3 dosage of 30 mg Fe/L were obtained, with total COD removal efficiency of 76.8%. Carbon balance analysis showed that FC-HRAS increased organics capture proportion by 91.8% while reducing loss from oxidative metabolism compared to HRAS. The potential mechanism of enhanced carbon capture for FC-HRAS was further explored. Adding Fe(III) caused coagulation of organics by increasing the Zeta potential in wastewater. Impacted by charge neutralization “compression” and coagulation floc “encirclement”, sludge particle sizes decreased, leading to increases of internal surface area and adsorption site of sludge for binding with bacteria; it facilitated the biological flocculation of FC-HRAS. Meanwhile, Fe(III) binding with proteins in EPS induced formation of “protein shell – β polysaccharides kernel” sludge structure and reduction of sludge negative charge, which intensified sludge stability and agglomeration. These factors explained the increase in organics capture proportion. The decrease in metabolism loss of organics could be attributed to the increase in organics transfer resistance in sludge EPS and selective elimination of heteromorphic bacteria (e.g., denitrifiers) in sludge. This work provided guidance for energy-neutral and cost-saving wastewater treatment in China.

New insight into the temperature effect on adsorption of cationic guar gum on halloysite – properties of the obtain systems

The manuscript presents the new insight into temperature effect on the adsorption and adsorption kinetics of cationic guar gum (CGG) on the halloysite surface (NH). The polymer/clay mineral hybrid materials and stability of the CGG/NH suspensions were analyzed using the following methods: UV-Vis, FT-IR, XRD, SEM-EDX, nitrogen adsorption/desorption, CHN and electrokinetic potential measurements. According to the results the increase of temperature increases both the adsorption of CGG on NH and stability of the CGG/NH suspensions. Thus CGG can effectively stabilize the NH suspensions at higher temperatures. The textural properties of the obtained hybrid materials were also strongly influenced by temperature. It was also observed that the CGG adsorption on NH is spontaneous, endothermic and thermodynamically privileged (ΔGo15 C=-12.90kJ/mol; ΔGo25 C=-14.03kJ/mol; ΔGo35 C=-16.34kJ/mol; ΔHo15 C-30 C=37.15kJ/mol; ΔSo15 C-35 C=0.17kJ/mol). The mechanism of this process can be regarded as a physisorption. The adsorption kinetics was adjusted to the multi-exponential equation. The presented results have a great application potential in wastewater or water treatment processes.

Mechanistic Insight for Disinfection Byproduct Formation Potential of Peracetic Acid and Performic Acid in Halide-Containing Water.

Peracetic acid (PAA) and performic acid (PFA) are two major peroxyacid (POA) oxidants of growing usage. This study reports the first systematic evaluation of PAA, PFA, and chlorine for their disinfection byproduct (DBP) formation potential in wastewater with or without high halide (i.e., bromide or iodide) concentrations. Compared with chlorine, DBP formation by PAA and PFA was minimal in regular wastewater. However, during 24 h disinfection of saline wastewater, PAA surprisingly produced more brominated and iodinated DBPs than chlorine, while PFA effectively kept all tested DBPs at bay. To understand these phenomena, a kinetic model was developed based on the literature and an additional kinetic investigation of POA decay and DBP (e.g., bromate, iodate, and iodophenol) generation in the POA/halide systems. The results show that PFA not only oxidizes halides 4-5 times faster than PAA to the corresponding HOBr or HOI but also efficiently oxidizes HOI/IO- to IO3-, thereby mitigating iodinated DBP formation. Additionally, PFA's rapid self-decay and slow release of H2O2 limit the HOBr level over the long-term oxidation in bromide-containing water. For saline water, this paper reveals the DBP formation potential of PAA and identifies PFA as an alternative to minimize DBPs. The new kinetic model is useful to optimize oxidant selection and elucidate involved DBP chemistry.

Autocatalytic formed bamboo-like N-doped carbon nanotubes encapsulated with Co nanoparticles as highly efficient catalyst for activation of peroxymonosulfate toward degradation of tetracycline

Co-based catalysts activated peroxymonosulfate (PMS) for organic pollutants degradation has been extensively studied. Co dissolution of Co-based catalysts would result in secondary environmental contamination. Co autocatalysis the formation of bamboo-like N-doped carbon nanotubes to confine Co nanoparticles (Co NPs). Herein, the N-doped carbon nanotubes encapsulated Co (Co@NCTs) were successfully synthesized through a one-step high-temperature calcination method at different temperatures. Co@NCTs-800 exhibited excellent catalytic performance, the degradation efficiency of tetracycline (TC) could reach 94.5% with only 0.05 g/L catalyst in activating PMS. In addition, the encapsulation of carbon nanotubes inhibits the dissolution of Co, the Co2+ dissolution was 0.0594 mg/L in 40 min in the system of Co@NCTs-800/PMS. Free radical quenching tests, electron paramagnetic resonance, and electrochemical measurements revealed that the non-radical route was dominated by tetracycline degradation, with singlet oxygen (1O2) and electron transfer as the principal active species. The N-doped carbon nanotubes can effectively encapsulate Co, which not only reduces the leaching of Co but also play a synergistic role with Co in degrading organic pollutants. In addition to this, the degradation mechanism and pathways of TC were further investigated. The Co@NCTs-800/PMS system was also able to successfully decompose a variety of organic contaminants, demonstrating that it has real application potential in wastewater.

Strategy for the cultivation of Chlorella vulgaris with high biomass production and biofuel potential in wastewater from the oil industry

This work aimed to provide a biochemical characterisation of Chlorella vulgaris biomass cultivated with daily supplementation of produced water. The simultaneous phytoremediation and production of biomolecules and bioproducts of commercial interest were analysed and discussed. Cultures were grown in laboratory scale photobioreactors for 26 days in 1.5 L of BG11 medium, with daily supplementation of 50 mL of non-autoclaved produced water (TPW) or distilled water (TDW). Biomass production differed among the control (3.86 g L−1), TPW (1.69 g L−1), and TDW (1.82 g L−1). The TPW-treated culture showed a high concentration of carbohydrates (40.19 %) with a bioethanol production of 18.22 mL 100 g−1 of biomass. The content of carotenoids (2.4μg mL −1), protein (22.83 %), and lipids (21.53 %) were also determined. The lipid composition consisted mostly of palmitoleic (5.42 mg g−1), γ-linolenic (3.02 mg g−1), and linolelaidic (1.94 mg g−1) acids, which gave the oil the ideal properties for quality biodiesel. In addition, the high phytoremediation efficiency of heavy metals such as copper (70.00 %), manganese (76.89 %), and molybdenum (97.82 %), as well as total petroleum hydrocarbons (48.59 %), were also detected. Therefore, TPW can be a promising alternative for phytoremediation of chemical compounds, while utilising effluent from the oil industry to produce a high content of valuable biomass, biomolecules, and biofuels.

Synthesis of 3D graphene-based materials and their applications for removing dyes and heavy metals.

Contamination of water streams by dyes and heavy metals has become a major problem due to their persistence, accumulation, and toxicity. Therefore, it is essential to eliminate and/or reduce these contaminants before discharge into the natural environment. In recent years, 3D graphene has drawn intense research interests owing to its large surface area, superior charge conductivity, and thermal conductivity properties. Due to their unique surface and structural properties, 3D graphene-based materials (3D GBMs) are regarded as ideal adsorbents for decontamination and show great potential in wastewater or exhaust gas treatment. Here, this minireview summarizes the recent progress on 3D GBMs synthesis and their applications for adsorbing dyes and heavy metals from wastewater based on the structures and properties of 3D GBMs, which provides valuable insights into 3D GBMs' application in the environmental field.

In Vitro Evaluation of Bio Reduction of Hexavalent Chrome by Marine Microorganisms Isolated in the Cartagena Bay for Wastewater Treatment

Contamination problems by heavy metals and specifically by hexavalent chromium generated by different production processes impact aquifers worldwide and require effective remediation methods for their control. The exploration of microorganisms in saline environments with the capacity to bio reduce hexavalent chromium (????6+) to trivalent chromium (????3+), allows an alternative to the use of biotechnological processes, reducing its toxicity. In the present study, marine microorganisms were isolated from water and sediments, adapted to high concentrations of hexavalent chromium, from 300ppm to 1000ppm with bio reductive potential in wastewater. Bio reduction bioassays were carried out in selective liquid and solid culture media, to which potassium dichromate (K2Cr2O7) was added. Morphological and biochemical identification was carried out with API, preserving colonies. Spectrophotometric validation was developed to evaluate (???? 6+), verifying the bio reduction efficiency in laboratory bioassays with King broth and 300 ppm of potassium dichromate. The different broths were evaluated for enrichment, being the nutritive broth and King the best, showing high turbidity and growth in a short time. Among bacteria isolated from water and sediment, the latter showed rapid growth from 18 to 24 h. Gram positive and negative bacilli (Bacillus subtilis, Bacillus brevis, Bacillus megaterium, Escherichia coli and Citrobacter kosseri) were found at 500/1000 ppm and biochemically characterized. Bio reduction percentages greater than 91% were obtained at 96 h, in concentrations of 300ppm of hexavalent chromium. Thanks to the selective isolation, tolerance and resistance to hexavalent chromium, these microorganisms proved to be bio reductive of this metal. Therefore, the use of these microorganisms on a full scale can be considered as a result for wastewater treatment where hexavalent chromium is used. Likewise, the use of microorganisms used in the bio reduction process is an alternative to Environmental Microbial Biotechnology that will bring benefits by reducing contamination.

Intensification of brewery wastewater purification integrated with CO2 fixation via microalgae co-cultivation

Microalgae has presented significant potential in wastewater and flue gas purification process. In the present work, co-cultivation of Scenedesmus sp. 336, Chlorella sorokiniana UTEX1602 and Chlorella sp. L166 were investigated to achieve the target of simultaneous biomass accumulation, wastewater treatment and biological carbon fixation. The experimental results showed that when the mixture ratio of Scenedesmus sp. 336 and Chlorella sorokiniana UTEX1602 was set at 1:1 with the ventilation period of 6 h/d, the cell dry weight could reach 796.89 mg/L. The maximum removal efficiency of NH3-N, TN, TP and COD were 96.22%, 90.57%, 97.37% and 78.83%. The contents of chlorophyll, carotenoid and carbohydrate were 16.05, 9.57 and 30.42 mg/L. The productivity of lipid and protein could achieve 20.82 and 142.12 mg/L. The CO2 fixation rate and carbon removal efficiency were 32.09 mg/L/d and 52.21%, respectively. It could be observed that co-cultivation of different microalgae has the potential to intensity simultaneous wastewater purification and CO2 mitigation.

Determination of 18 bisphenols in aqueous and biomass phase of high rate algal ponds: Development, validation and application

High rate algal ponds (HRAP) are an alternative to conventional wastewater treatment with the potential for wastewater and biomass reuse. In this study, we report the development and validation of methods for analysing 18 bisphenols (BPs) in the aqueous and biomass phase of HRAP. For aqueous phase samples, obtained LLOQ ranged from 10 to 30 ng/L, and recoveries from 78% to 106%. The relative expanded uncertainty was highest at the lowest spiking level (100 ng/L) and ranged from 27% to 66% (BPA), while for the biomass, the LLOQ ranged from 25 to 75 ng/g dw, recoveries from 84% to 103%. The uncertainty ranged from 16% to 37% (BPA). On average, the influent contained 329, 144, and 21 ng/L of BPA, BPS and 4,4′-BPF, and the effluent 69 ng/L, 94 ng/L and <LLOQ, respectively. Only BPA was quantified in the algal biomass. The average removal of BPA was 80%, whereas the removal efficiency of BPS was 32%. To our knowledge, this is the first study analysing a wide range of BPs in both aqueous and biomass phase of HRAP treating real wastewater.

Growth and production of ornamental sunflower irrigated with dilutions of treated domestic sewage

The water and nutritional potential of wastewater has been frequently exploited as an alternative water source for the irrigation of crops, especially in regions affected by the scarcity of water resources. Thus, this study aimed to evaluate growth and production of ornamental sunflower (Helianthus annuus L.) cv. Anão de Jardim irrigated with different dilutions of treated domestic sewage in public-supply water. The experiment was conducted in completely randomized design with five treatments and four replicates, in a greenhouse, in the Experimental Area of the Agricultural Engineering Graduate Program of the Federal University of Recôncavo of Bahia, located in the municipality of Cruz das Almas - BA, Brazil. Treatments started seven days after transplanting of the seedlings and consisted of five dilutions of treated domestic sewage (TDS) in public-supply water (PSW) (100% PSW – control; 25% TDS + 75% PSW; 50% TDS + 50% PSW; 75% TDS + 25% PSW and 100% TDS). In the control treatment, plants were fertilized with 100% of the mineral fertilization recommendation, whereas plants in treatments with effluent received 50% of the nitrogen (N) and potassium (K) recommendation. Biometric (plant height, stem diameter, number of leaves, shoot fresh and dry matter and leaf area) and production (capitulum internal and external diameter, capitulum fresh and dry matter, beginning of flowering and full capitulum opening) indicators evaluated at harvest demonstrated that ornamental sunflower plants irrigated with 100% TDS showed similar performance to those irrigated with PSW, which makes it possible to infer on the possibility of replacing PSW by TDS in irrigation, along with the 50% reduction in the recommendation of N and K fertilization, with no damage to the growth and production of ornamental sunflower, cv. Anão de Jardim, thus leading to the saving of good-quality water and fertilizers.

Evaluating the performance of a decentralized graywater treatment system in a living building at Hampshire College, Amherst, MA, USA.

Decentralized graywater treatment systems are growing in popularity as the threat of water scarcity rises and wastewater's potential as a resource is recognized. In 2016, Hampshire College in Amherst, Massachusetts, completed construction of the R.W. Kern Center, a Living Building that incorporates physical filters and two constructed wetlands to treat graywater produced on-site. Grab samples of graywater were collected from four sites between August 2016 and March 2019. This study characterizes mixed graywater from all the building's fixtures and graywater from a coffee bar. Untreated mixed graywater was observed with median concentrations of 180mg/L for total suspended solids (TSS), 190mg/L for biochemical oxygen demand (BOD5 ), and 15mg/L for total nitrogen (TN), primarily in the form of total Kjeldahl nitrogen (TKN). Concentrations of TSS, BOD5 , and TN were reduced by 92%, 96%, and 73%, respectively, by the Kern Center's treatment system. Preliminary data from coffee bar effluent establish a wide range of high-strength graywater quality. Because Living Buildings by design explore the connections between people and their builtenvironments, this study also found that the behaviors of building occupants, particularly the café staff, had a direct impact on the functioning of the Kern Center's decentralizedgraywater treatment system. PRACTITIONER POINTS: On-site decentralized graywater treatment systems paired with waterless composting toilets are effective in reducing a building's water use and inmeeting net-zero water goals. Constructed wetlands can effectively treat graywater produced in acentral campus building with public spaces, office spaces, and a coffee bar. On-site decentralizedgraywater treatment systems require cooperation from bothbuilding occupants and water operators in order to function properly.

A methodology for the isolation of marine microorganisms tolerant to hexavalent chrome for its bioreduction potential in wastewater

Over the past few decades, complementary medicine therapy using medicinal plants have been developed in healthcare. Phytochemical studies about medicinal plants have been conducted to verify their potency as medicinal remedies in modern therapeutics. Dipterocarpus littoralis commonly known as Meranti Jawa in Indonesia is traditionally used to treat diseases such as diarrhea, diabetic and malaria. This study aimed to isolate bioactive compounds from D. littoralis using bioguided fractionation method. The bioactivity measured were antioxidant, antidiabetic, and antiplasmodial activity. Alpha-glucosidase and alpha-amylase assays were applied to estimate the in vitro antidiabetic activity of D. littoralis. The antioxidant activities were determined by using the free radical scavenging assays 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2-2″-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Analysis of total flavonoid and phenolic contents were expressed as Quercetin Equivalent (QE) and Gallic Acid Equivalent (GAE), respectively. The in vitro antiplasmodial activity test of methanol extract of D. littoralis was also conducted against Plasmodium falciparum strain 3D7. Purification of the ethyl acetate fraction of the methanol extract of D. littoralis resulted in an oligostilbenes namely α-viniferin (1). The structure of the α-viniferin was characterized by comprehensive spectral analysis including IR, 1D and 2D NMR, and in comparison with the literature data. Compound 1 showed an alpha-glucosidase and alpha-amylase inhibitory activity with IC50 values of 256.17 and 212.79 μg/mL, respectively. The in vitro antiplasmodial activity test against Plasmodium falciparum strain 3D7 at a concentration of 100 μg/mL revealed a strong antiplasmodial inhibitory activity with IC50 value of 2.76 μg/mL. Our findings indicated that α-viniferin (1) which is isolated from D. littoralis extract could be regarded as potential antidiabetic and antiplasmodial resources in the future.

بررسی عملکرد میکروجلبک در بخشهای مختلف تصفیهخانه فاضلاب با بکارگیری آنالیز آماری

بطور کلی مدیریت منابع آب و فاضلاب‎ برای دستیابی به توسعه‎ی اقتصادی پایدار امری ضروری است. امروزه به علت توانایی بالقوه‎ی پساب‎ها در آلوده‎سازی منابع غذایی و آب‎ها و همچنین امکان رشد انواع مختلف میکروارگانیسم‎های بیماری‎زا درون آنها، تاکید زیادی بر جمع‎آوری و رفع آلودگی از انواع پساب انجام می‎گیرد. از این رو لازم است علاوه بر استفاده از روش‎های کارآمد در تصفیه‎ی فاضلاب روش‎هایی توسعه یابند که به لحاظ اقتصادی نیز مقرون به صرفه می‎باشند. یافتن یک روش مناسب برای تصفیه‎ی فاضلاب و تخلیه‎ی ایمن آن به منابع آبی یک چالش بزرگ می‎باشد زیرا نیازمند در نظر داشتن مسائل مختلف فنی و اقتصادی است. یکتایی هر یک از این مسائل انتخاب یک روش مناسب برای تصفیه‎ی پساب را بسیار مشکل می‎سازد. کشت میکروجلبک‎ها یک گام مناسب برای تصفیه‎ی فاضلاب می‎باشد زیرا یک تصفیه‎ی زیستی ثالثیه همراه با تولید مقادیر قابل توجهی بیومس می‎باشد که می‎تواند برای مقاصد گوناگون مورد استفاده قرار گیرد. در این تحقیق به ارزیابی کارایی استفاده از میکروجلبک کلرلا ولگاریس برای بخش‎های مختلف تصفیه خانه‎ی فاضلاب مانند ورودی، ته‎نشینی اولیه، ته‎نشینی ثانویه و خروجی پرداخته شد نتایج تحقیق حاضر نشان داد که میزان حذف پارامترهایی چون نیتروژن کل، نیتروژن آمونیاکی، فسفر کل و اورتو فسفات از پساب شهری به ترتیب 87.5%، 99.4%، 81.25% و 86.95% می‎باشد.

Spatial distribution of pharmaceuticals in conventional wastewater treatment plant with Sludge Treatment Reed Beds technology

Pharmaceutical residues are an emerging environmental problem. It is strongly confirmed that pharmaceuticals are present in soils and environmental waters (surface, marine and even groundwater), and that wastewater treatment plant (WWTP) effluents are the main source of pharmaceuticals in the watershed. The aim of this study was to recognize the spatial distribution and seasonal changes of selected pharmaceuticals in conventional WWTP with Sludge Treatment Reed Beds (STRBs) technology used for dewatering and stabilization of sewage sludge, because these systems have never been studied in terms of pharmaceuticals distribution or removal potential.The research was conducted in conventional WWTP in Gniewino, where raw wastewater was treated using mechanical, biological and chemical removal of the organic matter and nutrients, and sewage sludge was treated with STRB. Determinations of pharmaceuticals (non-steroidal anti-inflammatory drugs - ibuprofen, paracetamol, flurbiprofen, naproxen, diclofenac and its metabolites) and basic parameters were carried out in samples of influent and effluent from WWTP and in the liquid phase of surplus activated sludge (SAS) as well as reject water from STRB.The potential of removal varied among target pharmaceuticals. Ibuprofen and naproxen were completely removed by the standard applied technology of the Gniewino WWTP. Diclofenac and its metabolites were the chemicals with the lowest removal potential in wastewater and the highest detection frequency. These pharmaceuticals were also detected in the liquid phase of SAS as well as in reject water. However, removal potential when using STRB was higher than 94% (mostly higher than 99%), independent of the season. Indeed, the STRB technology is not only efficient in sludge dewatering and nutrient removal (primary purpose), but also elimination of polar pollutants. Nevertheless, removal in STRB did not mean that pharmaceuticals were totally eliminated because these compounds could be “trapped and stored” in beds (by the process of sorption) or transformed into other products. This study is a starting point for further exploration of STRB technology for elimination of emerging pollutants.

The United Nations World Water Development Reports: A Comparison and Contrasts of 2016 and 2017 Reports

The UN 2030 sustainable development agenda places a huge emphasis on promoting economic growth by catering to social needs ranging from education, health, social protection, and job opportunities while tackling climate change and environmental protection. UN publishes thematic reports, the World water development report (WWDR) which focus on different strategic water issues to facilitate decision making for sustainable development. This article is a comparative review of UN-WWDR 2016 which focuses on water and job creation with UN-WWDR 2017 which elucidates on the potential of wastewater.

Methods used to determine the zeta potential of colloids in wastewater

Water is the vital element in the daily life of man and the value of his treatment is to look for the sustainability of the planet and to preserve human life. The study is descriptive and comparative. The objective was to propose the most appropriate method for the zeta potential determination of colloids in wastewater. The operational procedure requires the knowledge of more related parameters, which implies greater analysis and therefore greater economic investment. The methods described are: Electrophoresis, Electroosmosis, Flow potential and sedimentation potential. Of the four methods for the determination of zeta potential in wastewater it is concluded that the electrophoresis method is the most used until now, which is used in different areas in greater or lesser scale, as in the application of solutions with different types of pollutant, unlike the other methods mentioned above. The electrophoresis has varied designs in such a way that it can be built manually and be applicable from small experiments with more accessible and easy-to-get materials, allowing to vary the construction investment of the equipment according to the scale of the work in which it is to be applied this method.

Determination of the Dyeing Potential of Mint and Sage Crops Wastes on Wool and Cotton Fibers

ABSTRACTIn the present study, dyeing potential of waste water from distillation process was investigated for fresh and dried herbs of Menthaspicata (MS), Menthapiperita (MP), and Salvia officinalis (SO) species. Meta-mordanting method was used in the dyeing of wool and cotton fabrics in the presence of FeSO4·7H2O (iron) and AlK(SO4)2·12H2O (alum) mordants. The color of each dyed material was investigated in terms of the CIELab (L*, a*, b*, C, and h°) and K/S values. The surfaces of the samples were observed using a scanning electron microscope. It was observed that the color strength of fresh and dried plant is depended on the plant species, mordant, and fabric type. Best color intensity (K/S = 16.68) was obtained with iron mordant using fresh SO on cotton fabric. For wool fabric, the highest color strength (K/S = 9.62) was obtained with fresh SO in the presence of alum mordant. Presence of metal mordant for natural dyeing process of cotton with MS, MP, and SO extract has shown remarkable improvement in terms of dye adherence and fastness properties thus metal mordanting could be suitable alternative dyeing method for ecofriendly industrial application.

Microbial electrolysis cells for hydrogen production and urban wastewater treatment: A case study of Saudi Arabia

This paper reviews the status of microbial electrolysis cells (MEC) as a mean for hydrogen (H2) production and urban wastewater treatment method. A case study of the Kingdom of Saudi Arabia (KSA) under MEC concept was developed. KSA is the world’s third largest per capita water user country with no lakes and rivers. Every year, around 1.17 and 0.38 billionm3 of domestic and industrial wastewater is generated respectively. The KSA government is seeking sustainable solutions for wastewater treatment and waste-to-energy (WTE) production to bridge the ever increasing water and energy demand-supply gap. However, there is no WTE facility exists to convert the wastewater into energy. Moreover, the potential of wastewater is not examined as an energy recovery substrate. This study, for the first time, estimated that a total electricity of 434 MWe can be produced in 2015 from the KSA’s wastewater if MEC technology is employed. Similarly, an estimated total electricity of 612 and 767 MWe can be produced for the years 2025 and 2035 from the domestic and industrial wastewater by using MEC technology. A surplus electricity of 508 and 637 MWe for the years 2025 and 2035 respectively can be added to the national grid after fulfilling the energy requirement of MEC wastewater treatment plants. Collectively, MEC will contribute 20.4% and 25.6% share of the KSA government’s WTE target of 3GW in 2025 and 2035 respectively. A number of challenges in MEC such as ohmic and concentration losses, saturation kinetics and competing reactions that lower the H2 production are discussed with their potential solutions including, the improvements in MEC design and the use of appropriate electrolytes, antibiotics and air or oxygen.