2,555 research outputs found

    Optimizing the MBBR System and Integrating Nanoparticles to Improve Wastewater Treatment Efficiency

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    Wastewater treatment faces a growing challenge in removing nutrients and organic matter. This study aims to evaluate the effectiveness of the moving bed biofilm reactor (MBBR) system in removing nutrients and organic from municipal wastewater. The impact of different carrier filling ratios and hydraulic retention times (HRT) on the removal efficiency was systematically investigated. Moreover, the addition of nanoparticle additives to enhance system performance was evaluated. The optimal conditions for the MBBR system were 30-45% filling ratios and a 10-hour HRT, resulting in maximum removal efficiencies for biological oxygen demand (BOD5), chemical oxygen demand (COD) and ammonia (NH4+-N) with a percentage of 85.23%, 81.69%, and 54.45% respectively. Furthermore, adding nanoparticles improved BOD5 and COD removal efficiencies by 6.6% and 8.0% respectively, compared to the MBBR system without nanoparticles

    The fate of bacteria in urban wastewater-irrigated peach tree: a seasonal evaluation from soil to canopy

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    Irrigation with wastewater can be a solution to preserve and mitigate freshwater demand, in particular during drought periods. Unfortunately, wastewater, although being treated at different levels, could be a carrier of human pathogens (e.g., E. coli) and potentially contaminate crops for human consumptions.This study investigated the seasonal microbiological concentrations, on soil, shoot and fruit tissues of potted peach trees, following two irrigation treatments: freshwater (FW) and secondary urban wastewater without the final disinfection treatment (SW). E. coli was only detected in SW irrigated soil, whereas total coliforms (TC) and total bacteria counts (TBC) were similar in both treatments throughout the season. EndophyticE. coli, Salmonella spp. and TC were not detected in shoot and fruit, but a higher presence of total bacteria (TBC) was observed in SW-irrigated tree compared to FWirrigated tree. In particular, SW shoots had a higher load compared to fruits, thus showing a potential effect of leaf transpiration, that promoted the transfer of water-borne bacteria from soil to the epigeal part (shoot). The adoption of low-quality SW (even above the microbiological limits of the European Regulation 2020/741 for wastewater re-use in agriculture), when a drip irrigation method is applied, could be a valid alternative to save fresh water without compromising fruit safety

    Manajemen Risiko Produksi Akuaponik di PT Tanikota Agribudaya Edulestari

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    Aquaponic production results at PT Tanikota Agribudaya Edulestari (TABEL)  has not met the standards desired by the company. This is shown by the results of aquaponic vegetable and fish production which are still experiencing fluctuations. This fluctuation in production results is related to the risks that occur during the aquaponics production process. This research is qualitative and adopts a case study approach. The analysis method used is House of risk (HOR). This method involves HOR stage 1 to identify risk events and risk sources, as well as HOR stage 2 to formulate management strategies. The aim of this research is to find out what risks and sources of risk faced by PT TABEL and develop mitigation strategies to manage these risks. Based on the research results, it was found that there were 23 risk events caused by 22 risk sources in the aquaponics production process at PT TABEL. Based on the 22 risk sources identified, 8 priority risk sources were obtained, namely worker imbalance, frog-eye leaf spot disease, caterpillar pests, root rot disease, cleanliness of the place, rainy season, plants are not exposed to sunlight, and problematic fish seeds. In managing these sources of risk, 8 management action strategies have been determined which have been sorted based on implementation priorities, namely conducting routine evaluation and monitoring organized and digitalized production scheduling and record keeping, making pest traps, using biological control, arranging and rotating crops that are not exposed to sunlight, create a separate place for post-harvest activities, optimize the use of waring in roder tents, and improve good communication with fish seed suppliers

    Self-Supervised Learning for Visual Relationship Detection through MaskednBounding Box Reconstruction

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    We present a novel self-supervised approach for representation learning, particularly for the task of Visual Relationship Detection (VRD). Motivated by the effectiveness of Masked Image Modeling (MIM), we propose Masked Bounding Box Reconstruction (MBBR), a variation of MIM where a percentage of the entities/objects within a scene are masked and subsequently reconstructed based on the unmasked objects. The core idea is that, through object-level masked modeling, the network learns context-aware representations that capture the interaction of objects within a scene and thus are highly predictive of visual object relationships. We extensively evaluate learned representations, both qualitatively and quantitatively, in a few-shot setting and demonstrate the efficacy of MBBR for learning robust visual representations, particularly tailored for VRD. The proposed method is able to surpass state-of-the-art VRD methods on the Predicate Detection (PredDet) evaluation setting, using only a few annotated samples. We make our code available at https://github.com/deeplabai/SelfSupervisedVRD

    Treatment of tannery wastewater by different membrane bioreactors: A critical review

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    A multitude of tannery wastewater (TWW) is a key challenge for the tanning industry. Developing efficient and new technology is crucial to regulate the disposal of TWW. Many scientists developed a variety of types of membrane bioreactor-based technologies to treat TWW. This study performed a critical review to understand the existing membrane bioreactor-based TWW treatment technologies. The review revealed that many studies tried to understand the removal efficiency of the membrane bioreactor-based technologies for treating TWW. The study findings depicted that scientists tried to develop various types of membrane technologies, i.e., modified membrane bioreactor (MBR), anaerobic MBR, moving bed biofilm bioreactor (MBBR) and hybrid MBBR, osmotic membrane bioreactor (OMBBR), hybrid MBR. The MBBR technologies performed better than the existing MBR techniques among the currently employed MBR. The review suggests a set of future research domains for sustainable treatment of TWW by applying MBR. In the future, the research focus could be on the development of novel biocarriers, application of 3D printing and the implementation of process simulation to enhance process efficiency and sustainability. . The review will aid scientists in enhancing their comprehension of the processes associated with different MBR treatment technologies used for treating TWW. This will, in turn, accelerate the advancement of process parameters and techniques

    Response of Lettuce (Lactuca sativa L.) To Aquaculture Wastewater Treatment

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    The fish feed waste and litters are organic matter that can be a source of nutrients for plants. This study is aimed to determine the growth and production of lettuce (Lactuca sativa L.) treated with wastewater from hard-lipped barb culture of several population densities. The research was carried out from April through June of 2020 at the greenhouse of the Agrotechnology Study Program, Faculty of Agriculture, Djuanda University, Bogor, Indonesia. The controlled study used a randomized block design with one factor, wastewater from fish population density of 10, 20 and 30 per 21 L of water, and AB Mix as a control. Plants treated with the AB Mix were significantly superior to those plants treated with the hard-lipped barb farming wastewater, demonstrated by taller plants, more and larger leaves, larger stem diameter and leaf area, longer roots, greater fresh and dry weight, as well as a higher leaf nitrate content. The aquaculture wastewater at the tested fish density in this study did not support optimal growth of lettuce, so lettuce production is still very low compared to those grown with the AB mix

    Advanced treatment of toluene emissions with a cutting-edge algal bacterial photo-bioreactor: Performance assessment in a circular economy perspective

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    A novel approach for the treatment of VOCs (by using toluene used as a model compound) and the simultaneous conversion of carbon dioxide into valuable biomass has been investigated by using a combination of an activated sludge moving bed bioreactor (MBBR) and an algal photo-bioreactor (PBR). The first unit (MBBR, R1) promoted toluene removal up to 99.9 % for inlet load (IL) of 119.91 g m-3 d-1. The CO2 resulting from the degradation of toluene was then fixed in PBR (R2), with a fixation rate up to 95.8 %. The CO2 uptake was promoted by algae, with average production of algal biomass in Stage VI of 1.3 g L-1 d-1. In the contest of the circular economy, alternative sources of nutrients have been assessed, using synthetic urban wastewater (UWW) and dairy wastewater (DWW) for liquid renewal. The produced biomass with DWW showed a high lipid content, with a maximum productivity of 450.25 mg of lipids L-1 d-1. The solution proposed may be thus regarded as a sustainable and profitable strategy for VOCs treatment in a circular economy perspective

    Examining the role of glycoside hydrolases in local rheology of Pseudomonas aeruginosa biofilms

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    Current research strategies in the treatment of biofilm infections have focused on dispersal, in which bacteria are made to vacate the extracellular polymeric substance (EPS) surrounding them and return to a planktonic state where antimicrobial treatments are more effective. Glycoside hydrolases (GHs), which cleave bonds in EPS polysaccharides, have been shown to promote dispersal in Pseudomonas aeruginosa biofilms. The dispersal mechanism is possibly due to GHs’ ability to directly release bacteria from the EPS, disrupt EPS’ ability to regulate the environment, or reduce overall mechanical stability. In this work, passive microrheology is used to examine the relevance of the last mechanism by exploring the effects of three GHs (α-amylase, cellulase, and xylanase) known to disperse P. aeruginosa on local biofilm viscoelasticity. Compared to control studies in wild-type strains, it is found that treatment with all three GHs results in statistically relatively less elastic and stiffer biofilms, indicating that changes to mechanical stability may be a factor in effective dispersal. Both cellulase and xylanase were observed to have the greatest impact in creating a less stiff and elastic biofilm; these GHs have been observed to be effective at dispersal in the published results. Each GH was further tested on biofilms grown with strains that produced EPS missing specific polysaccharide components. Cellulase specifically targeted Psl, which forms the major structural and mechanical backbone of the EPS, explaining its efficacy in dispersal. However, xylanase did not appear to exhibit any affinity to any polysaccharide within the EPS based on the microrheology results. Overall, these results suggest that the local microrheology of the biofilms is impacted by GHs and that may be one of the factors that is causing the ability of these therapeutics to enhance dispersal

    Experimentell Studie av Flödesfält i Biofilmsreaktorer med Rörlig Bädd

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    With the rise in global energy prices, as well as energy consumption being the largest source of greenhouse gas emissions, biofilm-based systems utilized for wastewater treatment, such as moving bed biofilm reactors (MBBRs), have grown in popularity for their lower energy consumption compared to conventional activated sludge processes. However, this technology requires large amounts of energy to constantly distribute and suspend its biofilm carrier within the reactor by either aerators or mechanical mixers. Many studies have been done on optimizing the aeration systems, but limited research has been focused on the mechanical mixing systems. This master’s thesis project aims to narrow the research and data gaps in MBBR mechanical mixing by conducting scaled-down experiments to study the influence of different mixer configurations on carrier’s flow fields in a reactor tank. The main objective is to determine the conditions for good carrier mixing and their energy use efficiency. Other objectives include determining the effects of scaling on carrier flow fields and whether the experimental results can be used to help develop and validate MBBR computational fluid dynamics (CFD) models. The results showed that good carrier mixing occurred in conditions where (1) mixer height was 3 cm from the bottom of the tank, had no inclinations and positioned along a long wall; (2) mixer flows could maintain their momentum; (3) sufficient length was given for mixer jet streams to develop and widen; (4) there was a dual presence of vertical flow loops and horizontal bulk flow loops; (5) 2 mixers did not result in counter- rotating flows; and (6) 2 mixers were not positioned in one corner of the tank. The effects of scaling did not impact the carrier flow fields and was determine by comparing the experimental results from this study with the results from a previous experiment that utilized a smaller tank. The results from this study could qualitatively match with the results of the CFD model. Limitations that occurred during the study when trying to define “good mixing” were also discussed. Lastly, the thesis ends with stating future work and recommendations. Med stigande globala energipriser och en energiförbrukning som är den största källan till utsläpp av växthusgaser, har biofilmbaserade system för avloppsvattenrening, t.ex. biofilmsreaktorer med rörlig bädd (MBBR), ökat i popularitet tack vare sin lägre energiförbrukning jämfört med konventionella processer med aktivt slam. Denna teknik kräver dock stora mängder energi för att ständigt distribuera och suspendera biofilmbäraren i reaktorn med hjälp av antingen luftare eller mekaniska blandare. Många studier har gjorts för att optimera luftningssystemen, men begränsad forskning har fokuserats på de mekaniska blandningssystemen. Detta examensarbete syftar till att minska forsknings- och dataluckorna inom mekanisk blandning i MBBR genom att genomföra nedskalade experiment för att studera hur olika blandarkonfigurationer påverkar bärarens flödesfält i en reaktortank.Huvudsyftet är att fastställa villkoren för god blandning av bärare och deras energianvändningseffektivitet. Andra mål är att fastställa effekterna av skalning på bärarnas flödesfält och om de experimentella resultaten kan användas för att utveckla och validera CFD-modeller (Computational Fluid Dynamics) för MBBR. Resultaten visade att god bärarblandning inträffade under förhållanden där (1) blandarhöjden var 3 cm från tankens botten, utan lutningar och placerad längs en lång vägg; (2) blandarflöden kunde behålla sitt momentum; (3) tillräcklig längd gavs för blandarjetströmmar att utvecklas och breddas; (4) det fanns en dubbel närvaro av vertikala flödesslingor och horisontella bulkflödesslingor; (5) 2 blandare inte resulterade i motroterande flöden; och (6) 2 blandare inte placerades i ett hörn av tanken. Effekterna av skalning påverkade inte bärarens flödesfält och fastställdes genom att jämföra de experimentella resultaten från denna studie med resultaten från ett tidigare experiment som använde en mindre tank. Resultaten från denna studie kunde kvalitativt matchas med resultaten från CFD-modellen. Begränsningar som uppstod under studien när man försökte definiera "bra blandning" diskuterades också. Slutligen avslutas avhandlingen med att ange framtida arbete och rekommendationer.

    Improvement of HEK293 cell growth by adapting hydrodynamic stress and predicting cell aggregate size distribution

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    HEK293 is a widely used cell line in the fields of research and industry. It is assumed that these cells are sensitive to hydrodynamic stress. The aim of this research was to use particle image velocimetry validated computational fluid dynamics (CFD) to determine the hydrodynamic stress in both shake flasks, with and without baffles, and in stirred Minifors 2 bioreactors to evaluate its effect on the growth and aggregate size distribution of HEK293 suspension cells. The HEK FreeStyle™ 293-F cell line was cultivated in batch mode at different specific power inputs (from 63 W/m³ to 451 W/m³), whereby approx. 60 W/m³ corresponds to the upper limit, which is what has been typically described in published experiments. In addition to the specific growth rate and maximum viable cell density VCDmax, the cell size distribution over time and cluster size distribution were investigated. The VCDmax of (5.77 ± 0.02) · 10⁶ cells/mL was reached at a specific power input of 233 W/m³ and was 23.8% higher than the value obtained at 63 W/m³ and 7.2% higher than the value obtained at 451 W/m³. No significant change in the cell size distribution could be measured in the investigated range. It was shown that the cell cluster size distribution follows a strict geometric distribution whose free parameter p is linearly dependent on the mean Kolmogorov length scale. Based on the performed experiments, it has been shown that by using CFD-characterised bioreactors, the VCDmax can be increased and the cell aggregate rate can be precisely controlled
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