Biological Wastewater Treatment

Nitrous oxide (N2O) is a greenhouse gas formed during biological wastewater treatment under aerobic and anoxic conditions. Two reasons for high N2O emissions are low oxygen concentration during nitrification and low carbon/nitrogen-ratio during denitrification. In this full-scale study of N2O emissions from a sequencing batch reactor for treating digester supernatant, the oxygen concentration was reduced stepwise and the carbon/nitrogen-ratio was varied to investigate how N2O emissions were influenced. N2O concentrations were measured online in water and off-gas. A distinct relationship was found between low oxygen concentrations and high N2O emissions. N2O was formed in water during both nitrification and denitrification. Decreased oxygen concentration during nitrification led to increased nitrite concentration, which in turn led to increased N2O concentration in the subsequent denitrification phase. When nitrification resumed, accumulated N2O was stripped off to the atmosphere. A too low carbon/nitrogen-ratio resulted in increased N2O emissions in off-gas under longer-term conditions and increased risk of separate peak emissions. Very high N2O concentrations, over 76,000 ppm, were measured in the off-gas. Furthermore, the maximum N2O emitted during one cycle represented 217.9% of the total nitrogen load (36.2% of total nitrogen present in the bulk liquid at cycle start), among the highest emission levels measured from a full-scale municipal plant treating digester supernatant.

Nitrous oxide (N2O) is a greenhouse gas formed during biological wastewater treatment under aerobic and anoxic conditions. Two reasons for high N2O emissions are low oxygen concentration during nitrification and low carbon/nitrogen-ratio during denitrification. In this full-scale study of N2O emissions from a sequencing batch reactor for treating digester supernatant, the oxygen concentration was reduced stepwise and the carbon/nitrogen-ratio was varied to investigate how N2O emissions were influenced. N2O concentrations were measured online in water and off-gas. A distinct relationship was found between low oxygen concentrations and high N2O emissions. N2O was formed in water during both nitrification and denitrification. Decreased oxygen concentration during nitrification led to increased nitrite concentration, which in turn led to increased N2O concentration in the subsequent denitrification phase. When nitrification resumed, accumulated N2O was stripped off to the atmosphere. A ...

[Objective] Plasmodium vivax predominantly infects many people in numerous tropical areas, including Southeast Asia, the Western Pacific, the Americas, and the Eastern Mediterranean. The uniqueness of forming dormant stages can lead to relapse in vivax malaria upon further infection. This study used molecular docking and dynamic simulation to predict potential bioactive compounds from the Zingiberaceae plant family as inhibitors by targeting Plasmodium vivax Duffy Binding Protein (PvDBP). PvDBP-DARC molecular interaction is required to mediate the merozoite invasion process into red blood cells. Inhibiting this process can possibly control parasite growth and development. [Methodology] Molecular docking screening was conducted by using 138 natural compounds from the Zingiberaceae plant family targeting Plasmodium vivax Duffy binding protein (PvDBP). The top two compounds with the lowest binding energy were selected to be analyzed by pharmacokinetics prediction and molecular dynamic (MD) simulation. [Results] Molecular docking screening resulted in the top two compounds with the lowest binding energy value, including 5,7-dihydroxyflavanone (-9.3 kcal/mol) and pinostrobin (-9.2 kcal/mol). These compounds are predicted to have stronger interaction than chloroquine as a control. Furthermore, the potential compounds also interact with DARC binding site residues and maintain them during the molecular dynamic simulation process. Otherwise, chloroquine as a control cannot retain 75% binding residues towards PvDBP. A molecular dynamic study revealed that all three complexes have relatively similar stability. [Conclusions] We predicted that the two bioactive compounds (5,7-dihydroxyflavanone and pinostrobin) have the potential as merozoite invasion inhibitors.

[Objetivo] El objetivo fue determinar cuál de las dos especies de hidras (Hydra attenuata o Hydra viridis) resultaba más sensible a dos plaguicidas, para luego usarla como parte de la batería de organismos de prueba del Laboratorio de Estudios Ecotoxicológicos (ECOTOX). [Metodología] Para esto se utilizaron diluciones de dos de los plaguicidas más comúnmente usados en el cultivo de piña en Costa Rica y detectados en muestras de agua: el herbicida diuron y el insecticida etoprofos. Se realizaron bioensayos de toxicidad con cada una de estas sustancias y con una mezcla de estas. Se registró el estado morfológico de las hidras. Además, se evaluaron la concentración de efecto medio (EC50), la concentración letal media (LC50), y las interacciones de toxicidad según tres posibilidades: antagónica, aditiva o sinérgica. [Resultados] La H. attenuata fue la especie más sensible a ambos plaguicidas, con LC50s de 16,84 mg/L y 103,01 mg/L; y EC50s de 4,24 mg/L y 23,74 mg/L para diuron y etoprofos, respectivamente. Mientras tanto la H. viridis tuvo LC50s de 36,94 mg/L y 103,01 mg/L, con EC50s de 13,64 mg/L y 53,12 mg/L, también para diuron y etoprofos, respectivamente. La exposición a la mezcla de plaguicidas solo causó mortalidad a la H. viridis y tuvo efecto sinérgico en ambas especies. [Conclusiones] Estos resultados sugieren que la H. attenuata es la especie más apropiada para la evaluación de efectos de plaguicidas, pero se deben realizar más estudios sobre las interacciones de los contaminantes en mezclas, porque estas pueden modificar su toxicidad para diferentes especies.

El uso indiscriminado de plaguicidas altamente tóxicos en la agricultura ha producido contaminación de los suelos y deterioro de los ecosistemas. Una solución prometedora para este problema ambiental es la biorremediación, que incluye el uso de bacterias para degradar estas sustancias contaminantes. [Objetivo] El presente trabajo tuvo por objetivo el aislamiento, identificación y caracterización de cepas bacterianas con capacidad de degradar los plaguicidas clorotalonil y clorpirifos, para su potencial uso en la biorremediación de suelos contaminados. [Metodología] Las cepas fueron aisladas de suelos agrícolas mediante cultivos de enriquecimiento, que contenían clorotalonil o clorpirifos (20 mg/L) como única fuente de carbono. Las cepas aisladas se caracterizaron por su morfología, fisiológicamente por su respuesta a 48 pruebas bioquímicas y frente a 15 antibióticos, cinética de crecimiento, y molecularmente (amplificación del gen ADNr 16S). [Resultados] Se aisló una cepa bacteriana capaz de utilizar (y degradar) clorpirifos como fuente de carbono, identificada como Stenotrophomonas maltophilia y dos cepas bacterianas con capacidad parcial de utilizar clorotalonil como fuente de carbono, identificadas como Enterobacter cloacae y Ochrobactrum anthropi. Las tres especies bacterianas son bacilos Gram negativo y presentaron características fisiológicas diversas, incluyendo resistencia variable a ciertos antibióticos. [Conclusión] Se concluye que las bacterias aisladas tienen potencial biotecnológico para ser incorporadas en una estrategia de biorremediación de suelos contaminados, especialmente para eliminación de clorpirifos. Finalmente, se plantean perspectivas de investigación a futuro para dilucidar procesos más eficientes de degradación de clorotalonil mediante cometabolismo.

This article reviews the development potential of Aquaponics in Morocco, an emergent approach which integrates aquaculture with Hydroponics, whereby aquaculture effluent is used to fertilise plants in the hydroponic system. Aquaponics is the subject of an alternative solution to earth modern problems, linked to climate change, such as drought, soil degradation, food and water availabilities, negative impact of aquaculture on the environment, the use of chemicals and pharmaceuticals. This food production system has gained interest in the past five years, however, there is yet to be successful experiences or scientific publications in Morocco, although the economy of this country is based on two main sectors: agriculture and fisheries. The current paper was developed using a systematic, strategic and comprehensive literature review on peer reviewed publications on several themes, including aquaponics, aquaculture, hydroponics and horticulture, from 1960 to 2020. Over 59publications we...

Constructed wetlands (CWs) ha ve proven, to different extents, to be an interesting option for several types of industrial wastewaters . They are complex systems that integrate and assemble several components, such as substrate, liners, outlet and inlet structures, microor ganisms and plants, playing different roles in the wetland cos mos. An horizontal subsurface flow CW system, with Phragmites australis in expanded clay substrate, was established for tannery wastewater treatment, being in operation for 4 years at different hydraulic retention times. For about 1.5 year there were no relevant gains in terms of organics removal efficiency when comparing the CW unit with an unvegetated control. However, plants were resilient to the conditions imposed, presenting good propa gation and development. In general, the system provided high removal of organics from the tannery wastewater -up to 88% of biochemical oxygen demand (BOD 5 ) (from an inlet of 420 to 1300 mg L -1 ) and 92% of chemical oxygen demand (COD) (from an inlet of 808 to 3100 mg L -1 ), and to lower extents nutrient removal (up to 69% of NH 3 from an inlet of 45 to 100 mg L -1 ). The CW proved to tolerate organic loadings up to 780 kg BOD ha -1 d -1 . However, if the BOD discharge limits for tannery industry are set as a goal an organic loading of about 210 kg BOD ha -1 d -1 should not be exceeded. Bacterial dynamics within the system was assessed. Numerical analysis of Denaturating Gradient Gel Electrophoresis profiles showed high diversity within the system. No clear relation was established be tween the hydraulic retention time, time of operation and the bacterial diversity. Toxicity tests were performed to assess the effect of the tannery wastewater at the CW inlet and outlet on Trifolium pratense and Phragmites australis seed germina tion. The level of treatment encompassing the CW allowed for a wastewater toxicity decrease that has been revealed by several endpoints measured (germination percentage, shoot length, roo t elongation and b iomass growth). The system was able to deal with situations commonly found in ind ustrial scenarios, such as fluctuations in the organic loadings and interruptions in the feed, showing rob ustness and resilience to the impos ed conditions.

Many antibiotics are persistent to wastewater treatment processes. • SRT and temperature seem to influence the removal of clindamycin and ciprofloxacin. • Re-transformation of clindamycin during the wastewater treatment is likely. • The mass flows of ciprofloxacin and levofloxacin in sludge are difficult to assess.

Wastewater treatment plants (WWTPs) are not designed to purposefully eliminate antibiotics and therefore many previous investigations have been carried out to assess their fate in biological wastewater treatment processes. In order to consolidate previous findings regarding influencing factors like the solid and hydraulic retention time an intensive monitoring was carried out in a municipal WWTP in Germany. Over a period of 12months daily samples were taken from the in- and effluent as well as diverse sludge streams. The 14 selected antibiotics and one metabolite cover the following classes: cephalosporins, diaminopyrimidines, fluoroquinolones, lincosamide, macrolides, penicillins, sulfonamides and tetracyclines. Out of the 15 investigated substances, the removal of only clindamycin and ciprofloxacin show significant correlations to SRT, temperature, HRT and nitrogen removal. The dependency of clindamycin's removal could be related to the significant negative removal (i.e. produ...

The removal of mixture of two azo dyes, Acid blue 29 and Ponceau xylidine, was studied by heterogeneous Fenton and Fenton-type processes using hydrogen peroxide and sodium persulphate as oxidants in the presence of and nano and micro- particles as catalysts. The synthesised nano- particles were characterised using analytical techniques viz. FT-IR, TEM, EDX, powder XRD and VSM. We have examined the effects of particle size on the COD removal efficiency and the reusability of the catalyst after optimising pH, and concentrations of catalyst and oxidant. Combination of nano-  and hydrogen peroxide possessed higher COD removal efficiency, which was accelerated in acidic pH and inhibited at pH > 6. Total consumption of hydrogen peroxide confirmed the efficiency of the optimised parameters. The mechanism of the formation of intermediate ions and products are proposed. COD removal and consumption of hydrogen peroxide follow pseudo-first-order kinetics. The toxicity of the solutions was a...

Cyanide is highly toxic to our ecosystem. The main contributor of cyanide to the environment is the untreated or improperly treated wastewater coming from various industries like steel, metallurgical, mining, tanning, etc. Bioremediation is an inexpensive yet effective measure, compared to physico-chemical methods, for removal of cyanide from industrial effluents. In the present study, one indigenous bacterial strain was collected and isolated from the outfall of nearby coke-oven plant and identified as Bacillus sp. NITD 19 through 16S rRNA gene sequencing. The test strain was used for removal of cyanide from synthetic solution. Lethal dose analysis was performed and the strain was found to grow up to 100 mg/L initial cyanide concentration. One factor at a time (OFAT) analysis was performed to get the effective operational parameters for maximum removal by varying pH (6-10), inoculum load (1-4%), temperature (25-37 o C), and initial concentration

One of the most significant inputs in an aquaponic system is fish feed. Here, two satiation feeding (SF) levels (60% & 50%) have been tested. It aims to determine its effect on the water quality and the growth, hematological indices, and blood chemistry of Nile tilapia Oreochromis niloticus reared in nutrient film technique aquaponic system (NFTAS) containing upland kangkong Ipomea reptans within 1 month period and compared it in the recirculating system (RS). Results showed that the SF levels have an insignificant effect on the water quality between the systems mainly due to the nonoptimal pH level that influenced the nitrification efficiency and the inefficient uptake of nutrients by the plants in NFTAS. Consequently, the growth, hematological parameters, and blood chemistry of the fish reared in NFTAS have not improved compared with those in RS. However, the fish and the plant growth performance were better at 60% SF in both systems. Thus, 60% is suggested SF level when 200 individuals Nile tilapia O. niloticus tilapia fingerling (2.46 g, average initial weight) are reared within 31 days in a healthy and balanced NFTAS with 50 individuals upland kangkong I. reptans.

Constructed wetland systems (CWSs) can offer cost-effective wastewater treatment in developing countries like Pakistan. This study focused on optimizing design and operational parameters of CWSs in horizontal surface flow (HSF), vertical surface flow (VSF), and hybrid mesocosms for treating sewage and textile effluents using local hydrophytes: Lemna minor, Typha latifolia, and Eichhornia crassipes. Pollutants and heavy metals (Cd, Cr, Cu, Pb, Ni, and Zn) were removed under different flow configurations, bedding materials, hydrophyte species, and hydraulic retention times (HRT) to optimize the overall contaminant removal efficiency (RE). Key findings indicated that the hybrid CWS achieved a maximum RE of 63.62% for total suspended solids (TSS) and 57.9% for biochemical oxygen demand (BOD) at an HRT of 3 days, with efficiencies declining at longer retention times. Additionally, the hybrid system showed maximum metal removal, with Cd and Cr RE reaching 75.2% and 70.5%, respectively. The study also highlighted the critical role of hydrophyte species and HRT in optimizing RE. Furthermore, the choice of hydrophyte species significantly influenced pollutant removal, with treatment cells containing mixed hydrophytes achieving the highest removal efficiencies (63.62%), followed by Eichhornia crassipes with high Cd (643.33 mgkg-1) and Cr (1103.72 mgkg-1) uptake. A lower HRT of 3 days resulted in the highest overall removal efficiency of 57.5%, which decreased with longer HRTs (from 6 to 9 days). Optimizing design and operational parameters is crucial for maximizing CWS treatment potential.

In this paper we consider a nonlinear model of a biological wastewater treatment process, based on two microbial populations and two substrates. The model, described by a four-dimensional dynamic system, is known to be practically verified and reliable. First we study the equilibrium points of the open-loop system, their stability and local bifurcations with respect to the control variable. Further we propose a feedback control law for asymptotic stabilization of the closed-loop system towards a previously chosen operating point. A numerical extremum seeking algorithm is designed to stabilize the dynamics towards the maximum methane output flow rate in the presence of coefficient uncertainties. Computer simulations in Maple are reported to illustrate the theoretical results.

El presente trabajo habla sobre la escasez de agua que se vive en el Centro Universitario Valle de Teotihuacán y como la implementación de un baño seco beneficiará a la población y a la zona, ya que además de ahorrar agua, también enriquecerá el suelo con la composta que de este se derive, la instalación del mismo es una cosa sencilla y más bien se requeriría de un compromiso social de todos aquellos miembros de la Institución para que participen y se comprometan con llevar a cabo las instrucciones para su funcionamiento eficaz y sustentable, además de obtener un beneficio para el entorno y la comunidad.

Background: Currently, new agri-food technologies have unveiled the nutritional value of barley. Our study focuses on the nutritional enhancement of barley (Hordeum vulgare L.). This study compares the nutritional characteristics of fermented and unfermented barley from Tiaret, Algeria. The analysis focuses on various physicochemical parameters, mineral compositionand heavy metals. Methods: The methods applied included the determination of dry matter (AOAC 9001.1), lipids (AACC 86-38), pr oteins (AOAC 950.09), gluten (AACC 38-10.01) and fibers (AACC 32-01.01). Acidity and pH were measured according to the current AACC standards (02.02.02, 02.52.01). Phenolic compounds were extracted using Kondakova's methodand antioxidant activity was evaluated by DPPH. X-ray fluorescence spectrometry and atomic absorption spectrophotometry were used to determine mineral compounds and heavy metals. Result: Results revealed the significant differences between fermented and unfermented barley. Fermented barley showed higher water content (9.68% vs 6.34%), less protein (9.06% vs 10.76%), more lipids (1.91% vs 1.55%) and fewer total fibers (6.08% vs 8.06%). Fermented barley had higher acidity and lower pH. It is richer in polyphenols but lower in flavonoids. Mineral composition also varies, with generally higher levels in unfermented barley, except for calcium and chlorine. Both types of barley showed low concentrations of heavy metals. This study highlights the nutritional differences between fermented and unfermented barley, offering interesting perspectives for their use in the agri-food industry. The distinct profiles of these barley types suggest potential for targeted applications in food processing and product development, considering their specific nutritional attributes and functional properties, taking into account the consumer's consumption habits.

Bilge water is the main pollutant of shipboard; a saline, oily and greasy wastewater with chemical oxygen demand (COD) values higher than 3-15 g/L [1]. Bilge water can also be described as a suspension of colloidal matter, composed of water and solids, including suspended solids and dissolved solids [2]. Conventionally, bilges are usually treated with chemical or physicochemical processes such as flotation, separation by centrifuge, and/or filtration [1]. Nevertheless, the existing conventional methods for the treatment of bilge are expensive or taking long retention time to achieve the targeted quality levels, since a major part of the oil in bilge water is emulsified in very small colloidal form [3]. Ecofuel (Cyprus) Ltd, is the sole company in Cyprus that receives and treats this type of wastewater using a three-treatment steps process consisting of: i) Dissolved Air Flotation (DAF), ii) aerobic 200 m 3 Moving Bed Biofilm Reactor (MBBR) and iii) ozonation. The purpose of DAF is t...

Soluble reactive phosphorus (SRP), a bioavailable phosphorus form, contributes to over-eutrophication by stimulating uncontrolled algal growth. This study aims to determine the optimum treatment parameters for the SRP removal from synthetic wastewater using the alginateimmobilized cyanobacteria Spirulina platensis. S. platensis was immobilized in alginate beads with varying alginate concentrations (2.5%, 3%, and 3.5% w/v), and subjected to varying operation time (1, 2, and 3 days), and bead dosage (1.5, 2, and 2.5 beads/mL) for SRP removal using Box-Behnken experimental design. Resulting model indicated a strong predictive relationship with R2 = 0.9253 and p = 0.0212. Main effects of bead dosage (p = 0.01372), its quadratic effect (p = 0.01643), and its interaction with alginate concentration (p = 0.00465) were found to be statistically significant. Predicted optimum parameters (2.5% w/v alginate, 3 days, and 1.5 beads/mL) were validated and resulted in a lower SRP removal of 92.80 ± 0.73% with a percent error of 5.22% relative to a predicted SRP removal of 97.91%. Extrapolation of the prediction model to 100% outside the experimental region was verified resulting in SRP removal of 97.39 ± 0.08% with a percent error of 2.61% was achieved by adjusting the operation time to 3.4 days. The study shows promising potential of immobilized S. platensis beads in addressing over-eutrophication through significant phosphorus reduction.

Effluents from intensive pig farms present high nutrient concentration, mainly ammonium, contributing to water eutrophication and pollution. Microalgae ability to deplete inorganic nutrients makes them an efficient effluent bioremediation tool. Scenedesmus obliquus was grown in piggery effluent (without any pretreatment) diluted with tap water at 5%v/v (187±25mg/L N-NH4+) and compared with growth in synthetic Bristol media. A 21-days trial was performed in 1L bubble-column reactors illuminated by fluorescent and LED lamps(3klux). Microalgae growth was monitored through OD540nm, dry weight and Chlorophyll content and also by flow cytometry in terms of autofluorescence read in FL3 channel (>670 nm), cell size (FSC), internal complexity (SSC) and cell membrane integrity (PI). S. obliquus cells have grown slower in pig effluent (mmax=0.13-19d-1) than in Bristol media (mmax=0.46-0.50d-1) although after 15 days the biomass productivity observed for the pig waste cultivation, operated u...

The sugar cane is an agricultural activity that had used toxic pesticides for a long time. A tratability study was carry out for biodegradation of a pesticide mixture of 2,4- D, Diuron and Ametryn by using, in continuous flow, a tricking filter and a subsurface wetland in order to find the best couple photocatalitic system. The pesticide mixture studied was similar to the products used in this industry and its physicochemical characteristics were determinated. During the biological degradation of the pesticide mixture, the microorganism had the adequade environmental conditions of temperature, pH and nutrients, so they were not limiting the process. Chemical Oxygen Demand removal obtained were 44,8% and 35,4% for the tricking filter and the subsurface wetland respectively .These results showed that the pesticide mixture of 2,4-D, Diuron and Ametryn were not biodegradable in a tricking filter neither in a subsurface wetland because the toxic effect of these pesticides to the microorg...

The paper employed a range of ensemble learning techniques to forecast Chemical Oxygen Demand (COD) levels in Wastewater Treatment Plants (WWTP). By harnessing ensemble learning, the main objective is to enhance the accuracy and robustness of COD prediction models by capitalizing on the diverse strengths of multiple algorithms. Our experiment encompassed two distinct WWTP datasets, allowing us to comprehensively assess the efficiency and effectiveness of three ensemble methods. Firstly, Bagging operates by creating multiple versions of a predictor and combining their outputs to form an aggregated prediction. Secondly, Boosting algorithms such as AdaBoost, GBM, and XGBoost sequentially constructed powerful learners, focusing on previously misclassified instances to bolster predictive performance. Finally, Stacking methodologies combined predictions from multiple models using a meta-learner. The analysis of the results for various models across the two wastewater treatment plant datasets (WWTPDS1 and WWTPDS2) reveals distinct performance levels. The Bagging model exhibits a reasonable performance with WWTPDS1 (MSE: 0.0016, R2: 0.9351) and a slightly lower performance with WWTPDS2 (MSE: 0.0033, R2: 0.6787). The Boosting model outperforms with lower MSE and higher R2 values for both datasets (WWTPDS1 MSE: 0.0010, R2: 0.9751; WWTPDS2 MSE: 0.0028, R2:0.7384), indicating its better predictive accuracy and reliability. The Stacking model evaluated in the training phase, it showcases exceptionally low MSE and high R2 values (WWTPDS1 MSE: 0.0004, R2: 0.9712; WWTPDS2 MSE: 0.0009,R2:0.9213). In the testing phase, the Stacking model maintains strong performance (WWTPDS1 MSE: 0.0013, R2:0.9494; WWTPDS2 MSE: 0.0028, R2:0.7191).

The Study Targeted the Isolation of The Biologically Active Compounds from
The Pink Nectar of The Callisteon Viminalis Sample (LC). 3,5-Dihydroxy-6-Methyl-4h-
Theran-4-One (9.09), Hexadecanoic Acid Derivatives (4.45), 13-Docosenamide, (3.67)
Long-Chain Fatty Acid Esters, (3.29) 9-Octecenoc Acid (Oleic Acid (18.95), Respectively,
And That The GC-MS Analysis Gives Great Extraction Efficiency In Terms Of The Content
Of The Effective Compounds That Have Been Identified, And The Presence Of Vehicles
Indicates That The Sample (LC) May Be Derived From A Natural Source That Contains
Both Fats And Carbohydrates

is a Biochemical Engineer and Ph.D. in Chemical Engineering from the University of Santiago de Compostela, Spain. He holds a professor chair at the Pontificia Universidad Católica de Valparaíso, and is the Director of the Biotechnology Center of Curauma, a center of applied research, which belongs to the same university. Currently, he also leads the research line in Renewable Bioresource at Fraunhofer Chile Research. His main lines of research are environmental biotechnology, renewable energy, climate change, and innovation management. Additionally, he has developed an extensive body of work in the field of applied research, with more than 100 as project director, principal investigator or co-investigator, supported with more than 100 ISI publications and 19 contributions to book chapters.

Many sludge reduction processes have been studied for the minimization of sludge production in biological wastewater treatment. The investigations on most of these processes have monitored the increase of the soluble chemical oxygen demand, the sludge mass reduction, or the decrease of the floc size, but little information has been obtained on cell lysis and the change of the biological cell activity. However, employing any strategy for reducing sludge production may have an impact of microbial community in biological wastewater treatment process. This impact may influence the sludge characteristics and the quality of effluent. The objective of this study concerns the determination of the physiological state of activated sludge microorganisms during a sludge minimization process. A thermal treatment at 80 °C for 5, 20, 40 and 60 min was chosen in this study. Staining bacteria with CTC and SY-TOX green was used to evaluate biological cell activity and viability of cell types contained in activated sludge, respectively. The monitoring of cell activity and viability was performed using flow cytometry (FCM) analysis before and after thermal treatment of activated sludge. Results indicated an increase in the number of permeabilized cells and a decrease in the number of active cells, subsequent to the thermal treatment. The study also confirms the potential of FCM to successfully evaluate the physiological heterogeneity of an activated sludge bacterial population. Moreover, the experimentally observed correlations between the FCM results and the organic matter solubilization in activated sludge samples during thermal treatment revealed that the increase in the soluble organic matter concentration was predominantly due to an intracellular material release. Identifying the increase in activated sludge hydrolysis requires a precise knowledge of the involved mechanisms, and this study indicated that the FCM, used in conjunction with specific probes, could be a useful tool.

Background: Bio-remediation methods of organic pollutants are promising due to their high efficiency, low cost, and green chemistry. These methods are effective alternatives to traditional elimination methods. Methods: Bacillus cereus PTCC 1015S strain was used to eliminate acid blue 113 (AB113) and acid orange 7 (AO7) from aqueous solutions. The bacteria were activated in the Luria Bertani Broth (MILLER) culture medium. The effective parameters such as incubation time and temperature, pH of dye solution, dye concentration, and the bacterial inoculation quantity on decolorization were investigated. Kinetic and thermodynamic studies were done to clarify the different aspects of the introduced method. Also, the reliability of the method to remove studied dyes was investigated in dye factory wastewater samples. Results: The first-order kinetic model was the best model to describe the kinetics of decolorization. The obtained thermodynamic data showed that the elimination process was end...

delivering a hygienically pure effluent and by exhibiting a very high operational reliability. Advanced MBR wastewater treatment technology is being successfully applied at an ever-increasing number of locations around the world. In this chapter, the authors have covered several aspects of MBR, with an exhaustive overview of its operational and biological performance. Different configurations and hydraulics of MBR are presented, with attention given to the fouling phenomenon and strategies for reducing it. Also, the high quality of MBR effluent is discussed, whereas in comparison with CAS removals of organic matter, ammonia, phosphorus, solids, bacteria and viruses are significantly enhanced. Emphasis has been given to the improved capability of MBR to remove organic contaminants present at trace concentration levels (ng L -1 , µg L -1 and mg L -1 ), which to the authors' knowledge represents a first attempt to summarize the published literature on this subject. Finally, advantages and disadvantages of MBR over CAS are concerned. In conclusion, MBR represents an efficient and costeffective process that copes excellently with the growing needs for transforming wastewater into clean water that can be returned to the hydrological cycle without detrimental effects. Biological performance • Membrane bioreactor (MBR) • Trace organic pollutants • Virus removal • Wastewater treatment Abbreviations ABT Aminobenzothiazole AEO Alcohol ethoxylates AHTN 6-acetyl-1,1,2,4,4,7-hexamethyltetraline AOB Ammonium oxidizing bacteria APs Alkylphenols APEOs Alkylphenol ethoxylates BOD Biological oxygen demand BPA Bisphenol-A BT Benzothiazole CAS Conventional activated sludge COD Chemical oxygen demand 2,4-D 2,4-dichlorobenzoic acid DBPs Disinfection by-products DEET Meta-N,N-diethyl toluamide DO Dissolved oxygen 2,4-DP 2-(2,4-dichlorophenoxy) propionic acid E1 Estrone E2 17β-estradiol EBPR Enhanced biological phosphorus removal ED Electrodialysis EDCs Endocrine disrupting compounds EDI Electro deionization EDTA Ethylenediamino tetraacetate EE2 17α-ethinylestradiole EPS Extracellular polymeric substances F/M Food-to-microorganism ratio FS Flat sheet

A study was conducted to establish the potential of constructed wetlands in Morogoro Urban District, Tanzania, to remove helminths from wastewater. The standard wastewater treatment regime was failing to effect reliable removal of helminth eggs and larvae from six wastewater stabilization ponds. An alternative wastewater treatment regime for the ponds, coupled with a constructed wetland and a fishpond, was devised. Water, soil, and vegetable samples were tested for the presence of helminth larvae and eggs in a time series design over one growing season. From March to August 2014, experimental plots of carrots and Swiss chard were irrigated with wastewater that had been treated by the alternative wastewater treatment regime. It was found that the alternative wastewater treatment regime coupled with the constructed wetland and fishpond appeared to remove helminths completely. No helminths were found in the wastewater after it passed through the alternative system, and none were found in the market-ready carrots and chard. Numbers of helminth larvae and eggs showed evidence of seasonality, which is potentially useful knowledge for farmers in order to avoid helminth infection: almost all larvae were found at the end of the hot dry season. Monsoon rains followed and washed the helminth larvae and eggs away and none were found at the end of the season.

The Anaerobic Digester designed and constructed for waste ingestion from the Nigerian cocoa industry aims to harness abundant renewable energy from crop residues like cocoa rinds and groundnuts. This study evaluates the biogas potential of these sources in contributing to the country's overall energy needs, emphasizing the imperative for environmental sustainability. Focusing on reducing fossil energy consumption, greenhouse gas emissions, and minimizing environmental impact, the project advocates for a shift towards biogas for day-today energy requirements, presenting direct cost savings. The utilization of fossil fuel-derived energy is known to contribute to temperature increase, greenhouse gas emissions, noise pollution, and ground-level air pollution, all of which can be mitigated through biogas utilization. This initiative involves the design and construction of a 0.24m 3 pilot plastic fossil plant for biogas generation, aiming to "green" various applications, including domestic and industrial usage as well as transportation. The digester, constructed from high-density polyethylene (HDPE) plastic, demonstrates leak-free operation, further supporting its potential for long-term sustainability. Results from a 28-day retention period show a cumulative biogas yield, with a daily assessment indicating a gas yield of 0.0496 m 3 on the 12th day. The study highlights the positive and negative influences of temperature inequality gradients ≥34°C≤38°C on biogas production. This comprehensive research contributes valuable insights for the sustainable management of waste and the utilization of biogas as a viable alternative energy source.

Digestión de aguas residuales en cámaras modulares compactas por acción conjunta anaeróbica y aeróbica Gráfico 6 Grasas y Aceites del efluente de establecimiento educativo, comparado con el exigido por la NOM-1996-SEMARNAT-001 para cuerpo receptor tipo C. Gráfico 5 Fósforo Total del efluente de establecimiento educativo, comparado con el exigido por la NOM-1996-SEMARNAT-001 para cuerpo receptor tipo C.

Pre-ozonation is often used to enhance the biodegradability of recalcitrant compounds prior to biological treatment of wastewater. A usual shortcoming of such an approach is wasting ozone on other compounds that are already biodegradable. This research followed a groundbreaking approach of degrading a recalcitrant substance with ozone during biological treatment. Two parallel bench-top activated sludge processes were fed a synthetic wastewater containing typical biodegradable substances and also methylene blue at 5 mg/L. Ozone was applied continuously and directly into one of the activated sludge units at 17 mg/L based on inflow rate. The methylene blue was removed by 95% in the ozonated process compared with just 40% removal in the non-ozonated control. The removal in the activated sludge without ozonation was demonstrated to be mainly due to biosorption. The ozone oxidation reaction by-products were analyzed using GC-MS on volatile substances collected in the headspace above ozonated samples of methylene blue and most found to be biodegradable. These by-products are expected to be degraded and assimilated in the same process unit together with the other biodegradables in the feed stream by the activated sludge process. The reaction rate with organic substances depleted the dissolved ozone at such a rate that the inactivation of the treatment bacteria (and protozoa) was minimal, mostly affecting the filamentous bacteria. A concern that ozone, as a powerful disinfectant, could inhibit or kill the beneficial bacteria in the activated sludge process was proven to be incorrect.

This project focused on the production of maleic anhydride from benzene, aiming to compare
ChemCAD simulations with hand calculations to optimize the process for efficiency, cost-
effectiveness, and environmental sustainability. The primary objectives included analyzing
process flows, stream compositions, and utility/energy requirements, as well as identifying
discrepancies between simulation and manual methods. Key findings revealed that
ChemCAD provided accurate predictions of process performance, particularly in energy
balances and flow rates. Sensitivity analyses highlighted the significant impact of solvent
flow rate and temperature on separation efficiency, with higher flow rates improving maleic
anhydride recovery but increasing operational costs. Unexpected deviations in pump power
estimations between ChemCAD and hand calculations underscored the need for refined
heuristic methods. The study also emphasized the importance of optimizing process
parameters, such as solvent flow rate and temperature, to maximize product yield while
minimizing energy consumption and environmental impact. Advanced simulation tools like
ChemCAD proved more reliable than traditional hand calculations, offering precise insights
into process performance. These findings provide valuable recommendations for improving
the maleic anhydride production process, ensuring it is both technically and economically
viable while adhering to environmental and safety standards.

Diversity of nitrifying bacterial population was investigated in sludge samples taken from a full-scale biological wastewater treatment plant (WWTP) treating domestic wastewater by fluorescent in situ hybridization (FISH) during seasonal operation. Duplicate grab samples were collected in March 2003, June 2003, December 2003 and May 2004 from the aerobic tank of the treatment plant. FISH results were interpreted with system performance in terms of BOD 5 , TKN and NO 3 -N removals and also with operational parameters such as wastewater temperature and sludge age. BOD 5 removal efficiencies were always greater than 90% whilst TKN removal in a range of 69-95% were achieved during the monitoring period. Although there were variations in operational conditions of the biological treatment system both Nitrosomonas and Nitrosospira genera from AOB and Nitrobacter genus from NOB were found to be present in all samples examined.

The effects of climate change and the growing demand for water for domestic, industrial, agricultural and recreational activities have been led the use of treated wastewater (reclaimed water) for such applications. The artificial recharge of aquifers with treated wastewater can be an alternative way for restoring underground water volumes that can be used for satisfying some activities, particularly in water shortage areas or where their quality is not suitable for use. After a two-year monitoring period in the characteristics of the treated effluent suggest that it could be used for infiltration for aquifer recharge. A multicriteria analysis based on GIS was developed for site location of infiltration sites. The procedure has involved the combination of six thematic maps and environmental, technical and economic criteria, over an area of 6687.1 ha. About 6.4 ha were selected for suitable sites for infiltration and one of these sites (Quinta de Gonçalo Martins, Guarda) was selected ...

Background: Human hair can be used as an inexpensive and accessible adsorbent to remove a variety of pollutants from air. Although several studies have been done on removal of formaldehyde from wastewater by human hair, to date no study has investigated using hair to remove formaldehyde from air. Therefore, the aim of this study was to remove formaldehyde from synthetic contaminated air by a reactor packed with human hair. Methods: Air contaminated with formaldehyde was introduced into a cylindrical reactor packed with human hair at the initial concentration of 8500 mg/L. Formaldehyde concentration was measured in the influent and effluent of the reactor to indicate formaldehyde removal efficiency. Other measurements of parameters effective on formaldehyde removal were taken including amount of human hair and environmental temperature. Results: Results of this study revealed that each gram of human hair was able to remove 0.13 to 0.49 g of formaldehyde from air. Human hair adsorbed 98% of formaldehyde from synthetic contaminated air under 20˚C. These results demonstrate that increased temperature had a negative effect on formaldehyde removal. Results of this study show that human hair can be applied as a simple and inexpensive adsorbent to remove formaldehyde from industrial air exhaust. In addition, results of these tests can be considered as a small step to promote better air quality.

Wastewater treatment plants are important to many types of pharmaceutical processing. An important functional basis of such plants is through microorganisms, where biological activity is essential for breaking down chemicals and ensuring the water passed into a municipal system meets required cleanliness standards. There is an additional element in relation to microorganisms; this is with minimising the release of antimicrobial compounds or genetically modified organisms, which can promote antimicrobial resistance in the community. This paper follows on from a general overview of wastewater plants (published in Vol.29.2; July 2024), focusing on the chemical and physical operational aspects, including an assessment of some of the reasons why wastewater plants go wrong.

This invention relates to the field of wastewater treatment, specifically an improved Extended Aeration (EA) process with the inclusion of a Primary Settling Tank (PST) to enhance treatment efficiency, reduce system footprint, and lower operational costs. Background of the Invention: Extended Aeration (EA) is a widely used modification of the Activated Sludge Process (ASP) for wastewater treatment. However, conventional EA systems do not include a primary settling stage, requiring larger aeration tanks and higher energy consumption due to the presence of high Total Suspended Solids (TSS) and Biochemical Oxygen Demand (BOD). In high-strength wastewater applications, these limitations lead to increased capital and operational costs. This invention introduces a Primary Settling Tank (PST) before the aeration stage to reduce solids loading, optimize aeration efficiency, and improve overall performance.

Decentralized wastewater containing elevated salinity is an emerging threat to the local environment and sanitation in remote coastal communities. Regarding the cost and treatment efficiencies, we propose a passive aeration ditch (PAD) using non-woven polyester fabric as a feasible bubbleless aerator and biofilm carrier for wastewater treatment. Consideration has been first given to PAD’s efficacy in treating saline decentralized wastewater, and then to the impact of chemical oxygen demand-to-nitrogen (C/N) ratio and salinity on biofilm formation. A multispecies model incorporating the salinity effect has been developed to depict the system performance and predict the microbial community. Results showed that the PAD system had great capacity for pollutants removal. The biofilm thickness increased at a higher C/N ratio because of the boost of aerobic heterotrophs and denitrifying bacteria, which consequently improved the COD and total nitrogen removal. However, this led to the deterioration of ammonia removal. Moreover, while a higher salinity benefited the biofilm growth, the contaminant removal efficiencies decreased because the salinity inhibited the activity of aerobic heterotrophs and reduced the abundance of nitrifying bacteria inside the biofilm. Based on the model simulation, feed water with salinity below 2% and C/N ratio in a range of 1 to 3 forms a biofilm that can reach relatively high organic matter and ammonia removal. These findings not only show the feasibility of PAD in treatment of saline decentralized wastewater, but also offer a systematic strategy to predict and optimize the process performance.

A facile hot-pressing method was developed to improve membrane roughness. • The modified membrane demonstrated superior TN removal capability. • A stable biofilm was formed on modified membrane. • Phylotype OLB8 played a crucial role in enhanced denitrification.

Membrane-aerated bacterial-algal biofilm reactor (MABAR) is an emerging and novel technology in recent years, which has been attracting increasing attention due to its cost-effectiveness and superior removal performance of pollutants by versatile removal pathways in symbiotic bacterial-algal biofilm. However, the wider application of MABAR is hindered by the dilemma of insufficient algae biomass. In this study, an MABAR under natural sunlight was developed and operated for 160 d to access the feasibility of enhancing algae proliferation by natural lighting. Results showed that the MABAR with natural sunlight (nMABAR) demonstrated better performance of pollutants removal. High removal efficiencies of organic matter and NH4-N in nMABAR were 90 % and 92 %, respectively. In particular, the removal efficiency of TN in nMABAR, under less aeration, was up to 80 %, which was 15 % higher than the control reactor. The Chlorophyll-a content indicated that natural sunlight facilitated to algae growth in MABAR, and algae assimilation might be the dominant contributor to NH4-N removal. Moreover, there were microbial shifts in bacterial-algal biofilm in a response to the natural lighting, the nMABAR uniquely possessed a bacterial phylotype termed Thiocapsa, which could play an important role in bacterial nitrification. Algal phylotype Chlorophyceae significantly contributed to pollutants removal and synergistic relationship with bacteria. In addition, the superb performance of nMABAR under less aeration condition suggested that abundant algae were capable of supplying enough O2 for the system. These results provided insight into the natural lighting on algae-bacteria synergistic growth and cost-effective operation strategy for MABAR.

Microbial lipase is looking for better attention with the fast growth of enzyme proficiency and other benefits like easy, cost-effective, and reliable manufacturing. immobilized enzymes can be used repetitively and are incapable to catalyze the reactions in the system continuously. Hydrophobic supports are utilized to immobilize enzymes when the ionic strength is low. This approach allows for the immobilization, purification, stability, and hyperactivation of lipases in a single step. The diffusion of the substrate is more advantageous on hydrophobic supports than on hydrophilic supports in the carrier. These approaches are critical to the immobilization performance of the enzyme. For enzyme immobilization, synthesis provides a higher pH value as well as greater heat stability. Using a mixture of immobilization methods, the binding force between enzymes and the support rises, reducing enzyme leakage. Lipase adsorption produces interfacial activation when it is immobilized on hydrophobic support. As a result, in the immobilization process, this procedure is primarily used for a variety of industrial applications. Microbial sources, immobilization techniques, and industrial applications in the fields of food, flavor, detergent, paper and pulp, pharmaceuticals, biodiesel, derivatives of esters and amino groups, agrochemicals, biosensor applications, cosmetics, perfumery, and bioremediation are all discussed in this review.

RESUMO -O tratamento de uma água residuária com alta concentração de matéria orgânica foi investigado em dois reatores de leito móvel com biofilme (MBBR 1 e MBBR 2 ). O MBBR 1 e o MBBR 2 foram preenchidos, respectivamente, com os suportes Kaldnes K1 e Mutag Biochip. A área superficial para o crescimento do biofilme foi a mesma para os dois reatores. A carga orgânica superficial foi aumentada de 3,2 a 12,8 g DQO/m 2 .d. A remoção de matéria orgânica não foi afetada e a nitrificação mostrou-se bastante estável durante todo o período de operação do reator, independentemente do suporte utilizado. À medida que a carga orgânica foi aumentada, observou-se um aumento na espessura do biofilme e na fração de biomassa em suspensão. Notavelmente, a atividade das bactérias nitrificantes em suspensão foi responsável por mais de 40% da atividade nitrificante total dos reatores. O teor de polissacarídeos e proteínas totais da biomassa aderida aumentou quando o sistema foi submetido ao aumento gradual da DQO.

El presente trabajo de investigación tuvo como objetivo diseñar el proceso de tratamiento de aguas residuales municipales para reducir la contaminación hídrica en el distrito de Samanco, Áncash. Para recoger los datos se utilizó el método de la encuesta y se trabajó también mediante el juicio de expertos, los instrumentos de recolección de datos que se utilizaron fueron: un cuestionario, guías de análisis documental y una matriz de evaluación de alternativas, se trabajó con una muestra de la población que fueron 270 familias, siendo cada jefe de hogar la unidad de análisis. Las herramientas estudiadas que se emplearon para lograr el diseño del nuevo proceso de tratamiento fueron: análisis estadísticos promedios, un diagrama de árbol causa efecto, una matriz de selección y un análisis de criticidad, logrando obtener con la aplicación de estas herramientas los resultados que contribuyeron para el diseño de un sistema de tratamiento moderno y eficiente que reduz...