Granule Diameter Research Articles

Synergistic effects of the chitosan addition and polysaccharides-EPS on the formation of anaerobic granules

ABSTRACTConcomitant early granulation with chitosan addition under a syntroph-specific substrate and enhancement of extracellular polymeric substances (EPS) production were aimed at to build anaerobic granules with high syntrophic activities in a short period. Two laboratory-scale upflow anaerobic sludge blanket reactors were operated as control (R1) and chitosan addition (R2) reactors during early granulation (phase 1). Chitosan decreased the negativity of microbial surface charges (zeta potential) to −10.5 mV on day 58 which led to increases in average diameter sizes, nuclei and granule ratio of approximately 115 µm, 55.1% and 8.2%, respectively. While zeta potential in R1 slightly changed, this resulted in less microbial aggregation. Although microbial aggregation in R2 was rapidly triggered by chitosan addition during phase 1, its structure was clumpy with rough surface due to lack of EPS. Substrate switching to glucose increased polysaccharides-EPS during phase 2 which was synergistically improved on the structural characteristics of microbial aggregate in R2, that is, more spherical and compact, with a smoother surface. Rapid-growth microorganism was also boosted, which then dominated the outer layer of the aggregate. The Archaea clumps were observed at a deeper layer and were surrounded by Eubacteria, presumably acetogens, indicating a syntrophic relationship due to substrate association between these microbial groups.

Performance and Characteristics of Aerobic Granular Sludge Degrading 2,4,6‐Trichlorophenol at Different Volumetric Organic Loading Rates

Aerobic granular sludge represents a promising option for the treatment of wastewater contaminated by 2,4,6‐trichlorophenol (2,4,6‐TCP). Nevertheless, the need for high volumetric organic loading rates (vOLR) still constitutes a practical drawback, since the supply of an external carbon source for the treatment of low‐strength industrial wastewater would imply significant costs at full‐scale. This study investigates the possibility to sustain 2,4,6‐TCP degrading aerobic granules with low vOLR, preserving long‐term process performance. Sodium acetate was used as external carbon source for aerobic granules degrading 2,4,6‐TCP (20 mg/L), and its concentration in the influent was progressively reduced from 1000 to 420 mg/L. The effects on process performance, granule properties and microbial population dynamics were investigated: complete 2,4,6‐TCP removal was maintained, specific removal rates increased from 2.2 ± 0.5 to 4.3 ± 0.4 mg 2,4,6‐TCP/g VSS per hour (mg2,4,6‐TCP/gVSS · h) and a shift of granule diameter toward smallest size fractions occurred. Moreover, the qualitative evaluation of polyhydroxyalkanoates (PHA) inclusions in microbial cells suggested their active role in 2,4,6‐TCP degradation. The results showed that for low‐strength wastewater containing toxic substances like 2,4,6‐TCP, high concentrations of the external carbon source are required during the process start‐up, but not in the long‐term operation, thus reducing the operating costs significantly without compromising process performance: this represents an important step toward process scale‐up.

Operation mode and external carbon dose as determining factors in elemental composition and morphology of aerobic granules

Abstract The elemental composition and morphology of aerobic granules in sequencing batch reactors (GSBRs) treating high-nitrogen digester supernatant was investigated. The investigation particularly focused on the effect of the number of anoxic phases (one vs. two) in the cycle and the dose of external organics loading (450 mg COD/(L·cycle) vs. 540 mg COD/(L·cycle)) on granule characteristics. Granules in all reactors were formed of many single cells of rod and spherical bacteria. Addition of the second anoxic phase in the GSBR cycle resulted in enhanced settling properties of the granules of about 10.6% and at the same time decreased granule diameter of about 19.4%. The study showed that external organics loading was the deciding factor in the elemental composition of biomass. At 540 mg COD/(L·cycle) the granules contained more weight% of C, S and N, suggesting more volatile material in the granule structure. At lower organics loadings granules had the higher diameter of granules which limited the diffusion of oxygen and favored precipitation of mineral compounds in the granule interior. In this biomass higher content of Mg, P and Ca, was observed.

Insight into the short- and long-term effects of inorganic phosphate on anammox granule property

The short- and long-term effects of inorganic phosphate on property of anaerobic ammonium oxidation (anammox) granule were investigated in this study. Acute exposure to high-level phosphate (⩾50mM) induced the cytoplasm leakage. During a 195-day continuous-flow operation, the gradually increasing phosphate (up to 500mgPL−1) slightly affected the specific anammox activity, hardly impacted the heme c content, remarkably decreased the extracellular polymeric substances production and significantly stimulated the dehydrogenase activity of anammox granules. Microbial community analysis showed no shift in the dominant anammox strain and higher population but lower relative abundance of anaerobic ammonium-oxidizing bacteria compared to the control granules. Interestingly, novel anammox granules with a hydroxyapatite core were cultivated, which possessed excellent settleability, huge granule diameter and superior mechanical strength. This study supported the application of granule-based anammox process as a pre-processing treatment in phosphate-containing and ammonia-rich wastewaters.

Electron microscope based X-ray microanalysis on bioaccumulation of heavy metals and neural degeneration in mudskipper [Pseudapocryptes lanceolatus

The bioaccumulation of heavy metals and its probable cytological consequences in ciliated olfactory sensory receptor neuron (OSN) of two different groups of Pseudapocryptes lanceolatus has been studied using X-ray microanalysis in transmission electron microscopy (TEM-EDX) [i.e., Group I, collected near Kanchrapara (22.56°N 88.26°E) and Group II, collected near Tribeni (22.99°N 88.40°E) of West Bengal, India]. The ciliated OSN is a bipolar neuron and possesses a prolonged dendron with four to six cilia at the olfactory knob, perikaryon, and axon. Excess accumulation of copper (94.50%) and iron (83.81%) was noted under TEM-EDX in the cytoplasm of the olfactory knob as well as nucleoplasm of ciliated OSNs in P. lanceolatus (Group II). The degenerating ciliated OSNs show distinct features of lysis of the plasma membrane at the olfactory knob, disintegration of cytoskeletal structures in perinuclear cytoplasm and axoplasm, and fragmented chromatin fibers with granules (diameter, 20–30nm) in the nucleoplasm. Crowding of acetylcholinesterase-positive vesicles (diameter:, 30–40nm) at the terminal part of the axoplasm was related to accumulation of heavy metals in degenerating ciliated OSNs of P. lanceolatus (Group II). The recorded concentrations of heavy metals in the same organ among different groups of P. lanceolatus in varying geographical areas indicates the stress of concerned environmental health. This ultrastructural interpretation on the fish ciliated OSN is a prerequisite for monitoring environmental health as well as metallobiology of several neurodegenerative disorders in fish caused by bioaccumulation of heavy metals.

Formulated Feed for Strombus pugilis (Mollusca, Gastropoda) Allowed Effective Gonad Maturity

Fighting conch Strombus pugilis is one of six Strombidae species distributed throughout the Caribbean. It is used as food, as an aquarium organism and its shell are popular in jewelry production. Conch aquaculture has been done traditionally by extracting egg masses from wild adults. This is an issue for several conch species protected by CITES. Intensive conch culture requires good growth rates and gonad maturity under laboratory conditions using formulated feed. An evaluation was done of the effect of inclusion of the red algae Halymenia and Spirulina on gonad maturity in S. pugilis using two experimental diets containing low and high concentrations of these algae (2% and 8% of each). Each diet was fed to six groups of conch kept in 20 L aquaria at 27.5°C. They were fed twice daily at 0.1 g feed/conch for 105 days. Gonad development and digestive gland structure were analyzed with histological techniques. Analysis of gonad development and vitellus granule diameter were analyzed for the two treatments and a control (wild conch). Wild conch females exhibited a reproductive cycle with 100% maturity at the beginning of this study, followed immediately by spawning (in two peaks: 50% and 34%) and initiation of a new oogenesis cycle. Females fed the 8% H. floresii and 8% Spirulina diet exhibited two spawning peaks (75% and 100%) spaced a month apart, and larger yolk granules than those in the control and the 2% H. floresii and 2% Spirulina diet. Proteoglycan granule abundance in the digestive cells did not differ between treatments. H. floressi and Spirulina may function as a feeding stimulant, enhancing feed intake and promoting gonadal maturity in S. pugilis broodstock under laboratory conditions.

Starch characterization and ethanol production of duckweed and corn kernel

The objectives of this study were to characterize the chemical structure, physical properties, enzyme digestibility, and ethanol production of duckweed starch and compare them with that of corn starch (B73). Duckweed consisted of 23.3% starch (dry basis, db), which was less than B73 corn kernels (66.5%). The morphology of duckweed starch granules displayed disk/dome shapes with one side of the granule flat and diameters of 4–9 µm. Duckweed starch displayed a B‐type polymorph, having an average amylopectin branch‐chain length of DP 26.5, and 35.7% amylose; both were larger than corn starch counterparts (DP 21.3 and 31.0%, respectively). Cooked duckweed starch showed higher resistant‐starch content (14.1%) and a greater percentage of retrogradation after 7‐day storage (57.5%) than the cooked B73 corn starch counterparts (8.7 and 49.6%, respectively). Duckweed plant produced a smaller ethanol‐yield (12.0 g/100 g plant, db) but a greater ethanol‐conversion efficiency (90.8%) than the B73 corn kernels (33.7 g/100 g kernels and 89.4%, respectively).

Effect of biomass configuration on the behavior of pilot-scale anaerobic batch reactors treating dairy wastewater

Anaerobic sequencing batch reactors applied to the treatment of dairy wastewaters have received increasing attention in bench-scale studies, particularly because dairy plants intermittently operate. This study compared two mechanically stirred, pilot-scale reactors, the Anaerobic Sequencing Batch Reactor (ASBR) and the Anaerobic Sequencing Biofilm Batch Reactor (ASBBR), in the treatment of dairy-plant wastewater. The reactors were fed with wastewater from a dairy plant and were operated with two cycle times: 48 and 24 h. The organic matter concentration in the influent, measured as chemical oxygen demand (COD), was approximately 4500 mg l−1. The ASBR exhibited highly efficient removal of organic matter (92.8 ± 5.9%), with production of bicarbonate alkalinity and low concentration of volatile fatty acids in the effluent for both cycle times. In contrast, the organic matter removal efficiency of the ASBBR decreased from 92.3 ± 16.5% to 60.5 ± 16.5% when the cycle time was changed from 48 h to 24 h. Moreover, the ASBBR also presented higher levels of instability during operation, showing lower bicarbonate alkalinity concentrations and higher concentrations of volatile fatty acids in the effluent when compared with the ASBR. The superior results exhibited by the ASBR may be related to larger changes in its microbial ecology and biomass configuration that occurred because of its better microbial selection and adaptation conditions. Granule diameters decreased greatly over time; however, this reduction did not affect settleability, assuring the performance of the ASBR.

Physico-chemical and textural property of starch isolated from Chenopodium (Chenopodium album) grains

AbstractThe aim of current study was to isolate and evaluate the starch from Chenopodium album (LP) and Chenopodium album (LS) varieties for its physicochemical, particle size analysis, and textural properties. The starch isolated from C. album (LP) and C. album (LS) showed yield values of 37.59 and 47.30%, while amylose content of the mentioned varieties was found to be 16.75 and 19.11%, respectively. The starch from C. album (LS) showed higher values of water and oil binding capacities (178 and 225%, respectively), while as the corresponding values for C. album (LP) were found to be 169.5 and 222%. Laser diffraction particle size analysis showed unimodal particle size distribution profile with mean particle diameters of 10.52 and 10.64 μm for C. album (LP) and C. album (LS) starches, respectively. The granular size and shape of starches measured by Scanning Electron Microscope showed polygonal and angular shaped granules with respective average granule diameter of 1.021 μm and 1.033 μm in C. album (LP) ...

Effects of Lecithin Addition on the Properties of Extruded Maize Starch

Normal maize starch combined with lecithin (LEC) was treated at a moisture content of 30% and screw speed of 160 rpm by extrusion processing. Extrusion treatment decreased the X-ray intensities of maize starch, and the diffraction peak type of extrudates was changed from A to A + V. Extrusion processing increased the gelatinization temperature and decreased the gelatinization enthalpy. A drop in pasting temperature and viscosity of extrudates was found with increasing barrel temperature. Compared with native maize starch, scanning electron micrograph results showed that the surface was rough, distorted and the diameter of extrudate granule became bigger. The Fourier transform infrared analysis indicated that the characteristic peak at 1,734/cm−1 was observed for maize starch LEC extrudates. The forgoing data suggested that the esterification of maize starch with LEC occurred during extrusion processing. This work provided a method for the production of esterified starch with LEC that can be used in the food industry. Practical Applications This research had an objective to study the surface morphology, structure, viscosity and thermal properties. This study provided some basic information required for the production of low-viscosity starch extrudates using maize starch blended with enhanced technological properties that are comparable with maize starch using lecithin. The starch extrudates have been successfully applied in ice cream and bakery processing. Understanding the formula and extrusion conditions to alter its functionality in puffed ingredients will benefit the food industry and will allow for the expanded use of this ingredient in extrudate maize starch. Understanding of the changes during extrusion processing between maize starch and lecithin is required for necessary processing actions and decisions.

Numerical study on the penetration of ash particles in a three-dimensional randomly packed granular filter

The purpose of this study is to investigate the influences of granular bed depth, gas velocity and granule diameter on the grade collection efficiency in a three-dimensional randomly packed granular filtration model. The simulation results and experimental results showed the effect of granular bed depth on the overall collection efficiency and pressure drop. It is found the pressure drop approximately linearly correlates with the granular bed depth. Then, the effects of granular bed depth, gas velocity and granule diameter on the grade collection efficiency were studied using simulation method, and the results indicated that increasing the gas velocity could improve the grade collection efficiency of particles greater than 7μm while it is useless for the particles smaller than 5μm. Increasing the granular bed depth makes the grade collection efficiency reaches the maximum earlier and it has equal promotion for the particles of all size. The grade collection efficiency is also approximately linearly correlates with the granule diameter and the granule diameter influences the position of the “turning point one” and “turning point two”.

Ultrastructural studies on the nuclear elements in differentiating and degenerative ciliated olfactory neuron of Pseudapocryptes lanceolatus (Gobiidae: Oxudercinae)

The cellular event of neurogenesis and neural degeneration of ciliated sensory receptor neuron within the adult olfactory neuroepithelial system has been studied in Pseudapocryptes lanceolatus (Bloch and Schneider, 1801) under light microscope (LM), fluorescence microscope and transmission electron microscope (TEM: Morgagni 268D) respectively. The unilamellar olfactory apparatuses of P. lanceolatus were dissected and fixed in 2.5% glutaraldehyde and 4% paraformaldehyde in 0.1 M phosphate buffer (pH 7.2–7.4) at 4 °C for microscopical studies. The LM study indicates that the progenitor basal cell proliferates to form electron lucent basal cell which differentiates into ciliated sensory receptor neuron within the olfactory neuroepithelium. Investigation under fluorescence microscope using Acridine Orange revealed that the nuclear elements in differentiating stages of electron lucent basal cell, mature and degenerating sensory receptor cell show notable features of gradual condensation. TEM study indicates the subsequent condensation of chromatin granules (diameter ranging from 10 nm–20 nm to 15 nm–30 nm) in various differentiating stages of electron lucent basal cell. The mature ciliated sensory receptor cell possesses chromatinized nucleus with large accumulation of chromatin granules (diameter: 20 nm–30 nm) at the peripheral nucleoplasm whereas degenerating sensory receptor cell possesses fragmented chromatin fibers. Therefore, these distinctive features of chromatin condensation are assumed to be a prime subcellular indicator of neural aging of olfactory sensory receptor cell.

A sustainable method for effective regulation of anaerobic granular sludge: Artificially increasing the concentration of signal molecules by cultivating a secreting strain

This study introduces sustainable quorum sensing (QS) granulation for anaerobic granular sludge (AnGS) and investigates the efficiency of three types of signal molecules on regulating AnGS granulation. The signal molecules of a secreting strain cultured in a QS regulating reactor increased their concentrations in an expanded granular sludge bed reactor throughout the granulating process. Increasing content of autoinducer-2 (AI-2) strengthened interspecific QS communication and gave a best performance with larger granular diameters, higher extracellular polymeric substance (EPS) production and relative hydrophobicity (RH). N-butyryl-homoserine lactone (C4-HSL) QS regulation was also favorable for granular growth, but its regulation was less than that of AI-2-QS. The AnGS granulated under these two types of QS regulations guided more filamentous bacteria to take part in granulation. Under diffusible signal factor (DSF)-QS regulation, the sludge had a lower granular level with a smaller granule diameter, lower EPS production (RH) when compared that of control medium.

Use of Alkali-activated Aluminosilicatematerialto Enhancebiogas Production from Acidic Whey

The effect of the addition of novel alkali-activated material (AAM) granules to provide additional buffering capacity, pH stability and increased methane yields in batch scale anaerobic digestion was investigated.The experiments were carried out with 20%, 30% and 40% of acidic whey in 500 ml batch reactors by a single addition of AAM granules (diameter from 2 to 8 mm) at 37 ± 0.5x00B0;C during 30 days. Presence of the AAM in the batch reactors allowedto maintain optimal pH, thus increasingthe yield and rate of methane formation from acid whey.

Morphological and Chemical Composition Characterization of Commercial Sepia Melanin

Melanins are difficult to characterize because of their intractable chemical properties and the heterogeneity in their structural features. Melanin pigments, in fact, are composed of many different types of monomeric units that are connected through strong carbon-carbon bonds. Its high insolubility and undefined chemical entities are two obstacles in its complete characterization. The morphological characterization and particle size distribution for sepia melanin by Scanning Electron Microscopy (SEM) on surface structure and Transmission Electron Microscopy (TEM) to confirm the morphology obtained from SEM was done. Both results show that Sepia melanin is formed by many aggregates agglomerated together. These aggregates are formed also by small spherical granules with different size distributions that have been determined using image-J software. The small granule diameter obtained from different TEM and SEM micrographs were 100-200nm. EDS reveals that C and O were the most abundant in sepia melanin with concentration average concentrations of about 57% and 24% respectively. The major compositions of sepia melanin are C, O, Na, Cl, while the minor are Mg, Ca, K, S and N. From TEM micrograph at high resolution, it was possible to measure the distance between polymers layers of sepia melanin using image-J software and it was 0.323 nm = 3.23 Å.

Effect of spray dryer settings on the morphology of illite clay granules

<p class="R-AbstractKeywords"><span lang="X-NONE">Spray drying is an effective and common method for powder drying, e.g. clay. The morphology and properties of spray dried granules depend on properties of slurry and operational conditions of spray dryer. The aim of this study was to investigate the effect of spray dryer settings on the morphology of illite clay granules. </span></p><p class="R-AbstractKeywords"><span lang="X-NONE">Laboratory scale spray dryer was used. Operational conditions: inlet temperature 190-220˚C, outlet temperature 70-96˚C, spray dispersion is obtained using two-fluid nozzle where the slurry feed was varied from 4.5 to 15 ml/min and gas pressure 15-40 mm. Slurry was prepared from clay fraction under 2 µm without additives. Latvian illite clay from Iecava, Pavāri and Laža deposits was studied. Slurries with concentration 1, 8 and 15 mass% was used.The size and morphology was investigated by scanning electron microscopy, surface area and porosity by liquid nitrogen sorption.</span></p><p class="R-AbstractKeywords"><span lang="X-NONE">All obtained granules irrespective of </span><span lang="X-NONE">spray dryer settings</span><span lang="X-NONE"> were well-rounded and dense without large pores or holes, however the surface was rough. The mean diameter of granules was in range of 2.6-5.4 µm, depending on slurry feed rate. The surface area of produced granules mostly depended on clay composition and was in a range of 70-92 m2/g. Inlet temperature in a range of 190-220 °C was found to be appropriate to produce well dried clay granules (moisture content <10 wt%). </span></p>

Anaerobic ammonium oxidation (anammox) under realistic seasonal temperature variations: Characteristics of biogranules and process performance

In this study, the effects of realistic seasonal temperatures on the nitrogen removal performance of anaerobic ammonium oxidation (anammox) and the properties of the anammox granules were comparatively investigated for 330days. The results demonstrated that the nitrogen removal efficiency (NRE), nitrogen loading rate (NLR) and nitrogen removal rate (NRR) were decreased dramatically, as the temperature decreased from 31.2 to 2.5°C. However, the nitrogen removal performance recovered andante as the temperature increased gradually. After low temperature exposure, the settleability tended to worsen, and granules appeared to be more irregular with a smaller average granule diameter, and the extracellular polymeric substances (EPS) content increased slightly, while the specific anammox activity (SAA) decreased obviously. This realistic seasonal temperatures based research was an illation of the actual operation, and could be potentially implemented to maintain stability for the application of anammox technology.

Diameter control and stability maintenance of aerobic granular sludge in an A/O/A SBR

Diameter is the key factor that influencing the stability of granules. In this study, combined selective pressure generated by low strength wastewater (chemical oxygen demand, COD, 200±40mg/L), low hydrodynamic shear force (superficial gas velocity of 0.55cm/s and agitation of 180rpm), different sludge discharge mode and a sequencing batch bioreactor (SBR) with an alternating anaerobic/aerobic/anoxic (A/O/A) operational process were employed to limit the diameter of aerobic granules. Energy consumption was reduced as low superficial gas velocity and agitation were employed. Granulation process was completed after 40days. The matured granules with small diameter (d (0.9)<800μm) were stable without disaggregation during the experiment period (220days). The extracellular polysaccharide/extracellular protein (PS/PN) ratio increased along with granulation process, and maintained at a stable level in the following time. After granulation, the removal efficiencies of COD, NH4+–N, total nitrogen (TN) and phosphate (P) reached 99%, 98%, 90% and 99%, respectively. The majority of TN was consumed during aerobic stage after complete granulation. The effective TN removal was mainly due to the activities of denitrifying phosphate-accumulating organisms (DNPAOs) and denitrifying glycogen-accumulating organisms (DNGAOs).

A novel strategy for accelerating the recovery of an anammox reactor inhibited by copper(II): EDTA washing combined with biostimulation via low-intensity ultrasound

Excessive heavy metals are inhibitory or even toxic to microorganisms in biological wastewater treatment systems. Given the promising prospects of anaerobic ammonium oxidation (anammox), this work details a novel remediation strategy for preventing anammox failure due to heavy metal overload (in this study, Cu(II) overload). The strategy involves combining ethylenediamine tetraacetic acid (EDTA) washing with bioactivity stimulation via low-intensity ultrasound. Kinetic experiments and batch activity assays were employed to determine the optimal concentration of EDTA and washing time, and changes in reactor performance and granule characteristics were tracked by continuous-flow monitoring to evaluate the long-term effects. The two-step desorption process revealed that the Cu in anammox granules was primarily introduced via adsorption (approximately 84.9%) and that low-energy adsorption sites were predominant (accounting for 58.6%). The Cu internalized in the cells (approximately 12.5%) could then diffuse out of the cells and be gradually washed out of the reactor within 20days. Thereafter, ultrasound irradiation at intervals of 8days contributed to accelerated performance, with a nitrogen removal rate (NRR) increasing rate of 0.1971kgNm−3d−2. The NRR was able to return to normal levels within 64days, whereas the recovery of dehydrogenase activity (DHA) was hysteretic, requiring approximately 110days. Gradual improvements in granule diameter, settling properties, extracellular polymeric substances and heme content were also detected. Overall, these results demonstrate that external removal of the adsorbed Cu followed by internal repair of the metabolic system may represent an important and useful recovery method in wastewater treatment plant operation.

Interference colorimetry of starch granules

AbstractStarch granules viewed under a polarizing microscope may exhibit vivid interference colors – how can they be measured? A tilting compensator was used to generate interference colors, they were measured by spectrophotometry (400–700 nm at 10 nm intervals), and the weighted ordinate method was used to calculate chromaticity coordinates. There was a reasonable correspondence between the subjective terms used to describe interference colors, and those used for the CIE diagram. Three different charts of interference colors were measured by fiber‐optics – only one was close to the interference colors of the tilting compensator (r = 0.805 for CIE x, and r = 0.874 for CIE y, both P &lt; 0.005). The spectra of various interference colors were like sine waves, whereas the matching spectra from charts were irregular with occasional peaks or dips. Thus, radically different spectra shared very similar chromaticity coordinates. As anticipated from first principles, the diameter of starch granules had a strong effect on their chromaticity coordinates (from r = 0.78 to r = 0.87, all P &lt; 0.001). © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 352–357, 2016