Effect Of Aeration Research Articles

Comprehensive agricultural ecological effects of aeration on regenerated liquid fertilizer of mini flush toilet

The high concentration of organic waste liquid obtained from the mini flush pipeline discharge technology based on source separation has the potential for fertilizer utilization. However, there are concerns about the risk of secondary pollution. This study proposes the idea of aeration treatment for regenerated liquid fertilizers to induce beneficial changes in their material composition and properties. Initially, this study compares the characteristic changes in nitrogen transformation of liquid fertilizer through aeration treatment. Subsequently, it examines the effects of different types of liquid fertilizers on soil properties, plant physiology, and soil microbial communities. Finally, we elucidate the flow and distribution of nitrogen in soil, plants, and nitrogen-containing gas emissions in agricultural ecosystems through material flow accounting. The study found that aeration treatment can reduce the ammonia nitrogen ratio while increasing the proportions of nitrite nitrogen and nitrate nitrogen. The regenerated liquid fertilizer through aeration treatment not only significantly increased the chlorophyll, protein, and polysaccharide content of vegetable leaves (P < 0.05) but also reduced nitrate accumulation. Moreover, it can reduce the risk of soil nitrate nitrogen leaching and increase the diversity of soil bacterial communities, enhancing the ecological functions of bacteria involved in carbon and nitrogen cycling. Material flow accounting indicated that aeration treatment for liquid fertilizer could reduce gaseous nitrogen loss by 50.0 %, improve the nitrogen utilization efficiency of vegetables by 95.5 %, and enhance soil nitrogen retention by 11.4 %. Overall, the results show that aeration treatment can improve the agricultural utilization of liquid fertilizer and reduce the risk of secondary pollution, providing preliminary decision-making support for optimizing resource treatment strategies for mini-flush toilet fecal waste to realize the agricultural cycle.

Effects of aeration and centrifugation conditions on omega-3 fatty acid production by the mixotrophic dinoflagellate Gymnodinium smaydae in a semi-continuous cultivation system on a pilot scale

High production and efficient harvesting of microalgae containing high omega-3 levels are critical concerns for industrial use. Aeration can elevate production of some microalgae by providing CO2 and O2. However, it may lower the production of others by generating shear stress, causing severe cell damage. The mixotrophic dinoflagellate Gymnodinium smaydae is a new, promising microalga for omega-3 fatty acid production owing to its high docosahexaenoic acid content, and determining optimal conditions and methods for high omega-3 fatty acid production and efficient harvest using G. smaydae is crucial for its commercial utilization. Therefore, to determine whether continuous aeration is required, we measured densities of G. smaydae and the dinoflagellate prey Heterocapsa rotundata in a 100-L semi-continuous cultivation system under no aeration and continuous aeration conditions daily for 9 days. Furthermore, to determine the optimal conditions for harvesting through centrifugation, different rotational speeds of the continuous centrifuge and different flow rates of the pump injecting G. smaydae + H. rotundata cells into the centrifuge were tested. Under continuous aeration, G. smaydaeproduction gradually decreased; however, without aeration, the production remained stable. Harvesting efficiency and the dry weights of omega-3 fatty acids of G. smaydae + H. rotundata cells at a rotational speed of 16,000 rpm were significantly higher than those at 2,000–8,000 rpm. However, these parameters did not significantly differ at injection pump flow rates of 1.0–4.0 L min-1. The results of the present study provide a basis for optimized production and harvest conditions for G. smaydae and other microalgae.

Stress modulation strategies in Kluyveromyces marxianus: Unravelling the effects of shear force and aeration for enhanced specific ergosterol production

AbstractErgosterol, as a precursor for synthesising useful molecules like vitamin D2, possesses significant physiological functions in both fungal and human systems. In fungi, ergosterol plays a crucial role in stress responses. In contrast to Saccharomyces cerevisiae yeast, the changes in specific ergosterol content of Kluyveromyces marxianus under various stress conditions are less known. This study investigated how ergosterol content changes in response to different stress factors. Carbon to nitrogen (C/N) ratio was examined using experimental design. The effects of aeration and shear force beside constant overall volumetric mass transfer coefficient (KLa) were examined. Cell growth and specific ergosterol content were investigated using ethanol stress during a two-stage fermentation. Based on the results, contradictory settings regarding C/N ratio and shear force were found to be favourable for cell growth and specific ergosterol content. However, increased aeration consistently elevated specific ergosterol content and favoured cell growth as well (2.5-fold and 1.5-fold, respectively). In K. marxianus fermentations, higher ergosterol yield can be achieved through a two-stage fermentation (138.9 mg L−1 compared to 52.9 mg L−1), where the first stage provides favourable conditions for cell growth, and the second stage involves stress (beneficial for ergosterol production) conditions. Conclusions drawn from the two-stage fermentation results suggest that early transitioning of cell growth to the second phase will not result higher adaption and specific ergosterol content compared to the transition at the end of exponential growth phase.

The influence of reservoir water level on the hydraulic characteristics of spillway tunnel

Abstract The spillway tunnel for water discharging is very important in water conservancy and hydropower engineering. Spillway tunnel with inclined and elbow part near the outlet can be more easily adapted to the topographic and geological conditions than that near the inlet, and can limit the cavitation damage to the short tunnel near outlet. Therefore, it has been widely used in the case of discharging water with high head and large discharge. Cavitation induced by high speed flow may cause severe damage to the spillway tunnel surface. And aeration is a common measure for surface protection. Study on the hydraulic characteristics of water-air two-phase flow is of great significance for improving aeration effect. In this paper, the velocity, depth of water and Froude Number of spillway tunnel under different reservoir water levels are studied by using VOF method. The results show that the Froude Number decreases at first and then increases as reservoir water level becomes lower.

Aerobic composting characteristics of corn straw and pig manure under dynamic aeration

ABSTRACT The conventional aeration method is compulsorily continuous ventilation or aeration at equal intervals, and a uniform aeration rate does not vary during composting. A dynamic on-demand aeration approach based on the diverse oxygen consumption of microorganisms at different composting stages could solve the problems of insufficient oxygen supply or excessive aeration. This study aims to design an aerobic composting system with dynamic aeration, investigate the effects of dynamic aeration on the temperature rise and physicochemical characteristics during the aerobic composting of corn straw and pig manure, and optimise the control parameters of oxygen concentration. Higher temperatures and longer high-temperature durations were achieved under dynamic aeration, thereby accelerating the decomposition of organic compounds. Dynamic aeration effectively reduced the aeration frequency, the convective latent heat and moisture losses, and the power consumption in the middle and later stages of composting. The dynamic aeration regulated according to the oxygen concentration of 14%–17% in the exhaust was optimum. Under the optimal conditions, the period above 50 ℃ lasted 8.5 days, and the highest temperature, organic matter removal, and seed germination index reached 65.82 ℃, 37.59%, and 74.59%, respectively. The power consumption was decreased by 33.58% compared to the traditional intermittent aeration. Dynamic aeration would be a competitive approach for improving aerobic composting characteristics and reducing the power consumption and the hot exhaust gas emissions, especially in the cooling maturation stage, which was of great significance for realising the low-cost production of composting at scale and promoting the blossom of the organic fertiliser industry.

Aeration Alleviated the Adverse Effects of Nitrogen Topdressing Reduction on Tomato Root Vigor, Photosynthetic Performance, and Fruit Development.

To explore the compensation effect of aeration on tomato vegetative and reproductive growth in arid and semi-arid areas, a two-year field experiment was conducted with four micro-nano aeration ratios (0%, 5%, 10%, and 15%) and three nitrogen topdressing levels (80, 60, and 40 kg·ha-1) during the tomato growth period in Ningxia, China. The results showed that increasing the aeration ratio in the range of 0-15% was conducive to the enhancement of tomato root vigor (the ability of triphenyltetrazolium chloride to be reduced, 3-104%) and the leaf net photosynthetic rate (14-63%), favorable to the facilitation of plant dry matter accumulation (3-59%) and plant nitrogen accumulation (2-70%), and beneficial to the improvement of tomato yield (12-44%) and fruit quality. Interestingly, since the aeration ratio exceeded 10%, the increase in the aeration ratio showed no significant effects on the single-fruit weight, tomato yield, and fruit quality. Moreover, with aerated underground drip irrigation, properly reducing the traditional nitrogen topdressing level (80 kg·ha-1) by 25% was favorable for enhancing tomato root vigor (5-31%), increasing tomato yield (0.5-9%), and improving fruit soluble solid accumulation (2-5%) and soluble sugar formation (4-9%). Importantly, increasing the aeration ratio by 5% could compensate for the adverse effects of reducing the nitrogen topdressing level by 25% by improving the leaf photosynthetic rate, promoting plant dry matter accumulation, increasing tomato yield, and enhancing the soluble solid and soluble sugar accumulation in tomato fruits. Synthetically considering the decrease in the nitrogen topdressing amount, leading to plant growth promotion, a tomato yield increase, and fruit quality improvement, a favorable nitrogen topdressing level of 60 kg·ha-1 and the corresponding proper aeration ratio of 10% were suggested for tomato underground drip irrigation in the Yinbei Irrigation District of Ningxia.

Violent breaking-wave impacts. Part 4: A detailed analysis and comparison of field and 1:4 scale measurements on sloping and vertical walls including the influence of air and scale effects

Pressure and aeration measurements obtained under storm conditions on the steep-fronted masonry wall of a rubble-mound breakwater are analysed in detail, and the results compared with those obtained using a 1:4 scale freshwater model of the field test site. New insights are gained into the complex behaviour of the most violent impacts, with particular attention given to aeration and scale effects.The existence in the field of both low-aeration (LA) and high-aeration (HA) impacts is confirmed and new parameters introduced to facilitate further analysis. Maximum pressures (Pmax) up to 771 kPa are categorised and the magnitudes of the resultant impulses found to depend mainly on their durations. The alternate expansion and recompression (ERC) of air following a HA impact is shown to apply significant oscillatory pressures and forces to the wall. Information on the magnitude, period and damping of these oscillations is presented.The model results are initially scaled in accordance with the Froude law. In conditions comparable to those in the field, the highest pressure on the sloping wall is again found to occur in HA impacts with Pmax ≤ 3.17 MPa followed by ERC oscillations. Like those in the field, the oscillations at different elevations tend to come into phase with each other and can subject the wall to oscillatory forces of significant vertical extent. Both the initial excursion and the damping of the oscillations tend be greater in the model than in the field. The maximum forces on the wall also tend to be greater than those on the field breakwater, but the durations of the impulses tend to be shorter. This apparent trade-off between force and duration may indicate that the model is responding differently to the momentum flux of the incoming waves. Pmax ≤ 5.42 MPa are obtained when the model wall is vertical.Because the Froude law does not scale aeration effects correctly, model data are also scaled in accordance with the Bagnold-Mitsuyasu (B-M) law which increases the highest Pmax for the vertical wall to 20.97 MPa. An alternative assessment of the ERC oscillations is also made on the assumption that the trapped-air pockets are geometrically similar to ones that could occur in the field.Likely generic characteristics of violent wave-impacts are identified as are probable model scale-effects. Impact-pressure reduction curves derived from a numerical model are presented to emphasise the influence of entrained air on wave loading. Further work is recommended.

Effects of aeration on water quality in agricultural reservoirs in the northern Great Plains

Lerminiaux J, Norton B, Wilson RJ, Rimas R, Lavender TM, Finlay K. 2024. Effects of aeration on water quality in agricultural reservoirs in the northern Great Plains. Lake Reserv Manage. 40:264–284. Aeration of agricultural reservoirs is an encouraged practice in the northern Great Plains of Canada as it can improve water quality by reducing pathogenic bacteria and algal abundance. Cattle also prefer aerated water, resulting in greater weight gain. Despite its known benefits, agricultural reservoir aeration is still not uniformly adopted, largely given its cost of installation and maintenance. Wind powered aeration has been shown to be an eco-friendly and sustainable way to increase oxygen levels in agricultural reservoirs, but the mechanisms by which this aeration can improve water quality are not well documented. By comparing 5 aerated agricultural reservoirs to 5 unaerated agricultural reservoirs, we evaluated whether wind-powered aeration improves water quality. We measured dissolved oxygen, nitrogen, and phosphorus, algal biomass (as chlorophyll a), cyanobacteria abundance, and algal toxins (microcystin, anatoxin-a, and β-N-methylamino-L-alanine) in the aerated and unaerated agricultural reservoirs on a weekly basis over a 12-week period from mid June through August 2022. We found that the aerators were able to mix the water column and add oxygen to deeper regions of the agricultural reservoir, but this did not result in consistent improvements to any measured water quality parameter. The observed lack of a strong response to aeration suggests that this practice may provide only minimal water quality benefits, but aeration may still prove beneficial for deep (>2 m) and sheltered agricultural reservoirs that do not regularly mix from wind effects alone.

Organic Pollutants Removal in a Hybrid Constructed Wetland Wastewater Treatment Plant with an Aeration System

This study presents the efficiency of TSS and organic pollutants (BOD5 and COD) removal in a hybrid constructed wetland wastewater treatment plant (VF-HF type) with an aeration system. This study was conducted over 6 years (2017–2022) in a facility with a capacity of 4.5 m3/day located in southeastern Poland and designed to treat real domestic wastewater from a school building. The studied facility consists of a three-chambered septic tank, a pumping station with an aeration system, and two beds with vertical and horizontal flow planted with giant miscanthus and willow. As a result of artificial aeration, the dissolved oxygen concentration in wastewater after mechanical treatment increased significantly, by an average of 1.18 mg O2/L, and was negatively correlated with wastewater temperature. The cumulative pollutant removal effects of the treatment plant (primary settling tank + VFCW + HFCW) were 81% for TSS, 98% for BOD5, and 89% for COD. There was no statistically significant effect of aeration on the organic pollutant removal effects in the VF bed, and such an effect was found for the temperature of wastewater entering the VF bed. The TSS, BOD5, and COD removal effects in the VF bed and BOD5 in the VF-HF system were positively correlated with air temperature. The technological reliability of the treatment plant was 98% for TSS and 100% for BOD5 and COD. The use of artificial aeration of wastewater makes it possible to achieve high organic pollutant removal efficiency in SSF CWs and to compensate for limitations due to the reduction in the area of constructed wetland beds.

Influence of toilet flushing water when using an on-site faecal sludge treatment combining electrocoagulation-flotation and anaerobic digestion

Addressing the need for sustainable sanitation in public transport and tourism, this study evaluates electrocoagulation-flotation (ECF) combined with anaerobic digestion (AD) for treating synthetic human faecal sludge (FS). Especially the effects of influent aeration and the use of either rainwater or tap water for flushing on the efficiency of pollutant removal and methane production were investigated. In detail, flushing with rainwater combined with influent aeration resulted in the highest removal efficiency of total COD (tCOD), non-soluble COD (nsCOD), total nitrogen (TN), and total phosphate (TP) of 55 %, 27 %, 22 %, and 75 %, respectively, during ECF treatment, compared to 48 %, 15 %, 14 %, and 63 %, respectively, when tap water was used. As such, post-treatment is mainly necessary for the removal of TN. Combining flushing with rainwater and influent aeration also resulted in the highest faradeic efficiency (107 %) and the most insoluble iron coagulant formation. In contrast, the application of influent aeration during ECF of FS produced using rainwater flushing led to a decrease in methane production from 354 mL/g VS (when no aeration is applied) to 281 mL/g VS during subsequent AD. In conclusion, this study demonstrates that ECF can be applied as a good pre-treatment for sanitation water due to the high nsCOD and TP removal, by which ECF could replace, e.g., a septic tank. Furthermore, the potential of combining ECF with AD is demonstrated in view of energy recovery.

Looking deeper into the effects of scouring and aeration on membrane aerated biofilms: Analysis of nitrogen conversion, oxygen profiles and nitrous oxide emissions

This study investigated the effects of aeration and scouring strategies on the performance of Membrane Aerated Biofilm Reactors (MABRs) and the distribution of oxygen and nitrous oxide in the biofilm. Four flat sheet MABRs were operated with synthetic feed under different conditions: two with intermittent aeration (iMABR) and two with continuous aeration (cMABR). Scouring was induced by bubbling dinitrogen gas through the reactor bulk at low and high frequencies (LF and HF). In the iMABRs, a partial nitritation biofilm initially developed, but the biofilm adapted to the aeration strategy over time and became nitrifying. The cMABRs directly developed a nitrifying biofilm without a significant phase of partial nitritation. Limiting oxygen availability improved the overall performance with regards to total nitrogen (TN) removal by providing a better environment for anaerobic ammonium oxidation (Anammox) while limiting complete nitrification.Oxygen profiles were measured in the iMABR over time at different biofilms depths, showing that intermittent aeration led to various oxygen concentrations and temporal variations in the oxygen availabilities at different depths of the biofilm. Also, N2O emissions from the MABRs differed greatly between the different systems, but still remained lower compared to other reactor configurations for nitrogen removal, making the MABR technology a worthy alternative. The results showed large differences between the operating strategies of the MABRs and can help to gain more insight into the specific properties of MABRs for nitrogen removal.

Effect of Aeration and External Carbon Source on Nitrogen Removal and Distribution Patterns of Related-Microorganisms in Horizontal Subsurface Flow Constructed Wetlands

Nitrogen pollution of surface water is still a critical issue worldwide. In this study, a total of four treatments were conducted in horizontal subsurface flow constructed wetlands (HSSFCWs) to explore the removal rate of nitrogen in the carbon-deficient wastewater, including combination of aeration and external carbon source (CW_CA), external carbon source (CW_C), aeration (CW_A), and control group without aeration and carbon source (CW_CK). Results showed that the removal rates of total nitrogen (TN) in the enhanced treatments were increased compared with CW_CK. The highest removal rates of COD (66.56%), NH4+-N (73.51%), NO3−-N (79.31%), and TN (76.19%) were observed in the CW_CA treatment. The bacterial community structure at the fore and rear ends of HSSFCWs was simultaneously changed in the CW_CA and CW_C treatments, respectively. The highest richness index at both the fore and rear ends of HSSFCWs was found in the CW_CA treatment. The richness and diversity indices of CW_C declined at the fore ends of HSSFCWs, but increased at the rear ends of HSSFCWs. Furthermore, the functional bacteria and genes significantly changed among different treatments. At the fore ends of HSSFCWs, the highest relative abundance of nitrifiers and absolute abundance of amoA and nxrA were obtained in CW_A, and the highest relative abundance of denitrifying bacteria and absolute abundance of nirS, nirK, nosZ were found in CW_C. However, at the rear ends of HSSFCWs, the highest relative abundance of nitrifiers and denitrifying bacteria as well as the absolute abundance of related genes were also observed in the CW_CA treatment. Overall, CW_CA improved the nitrogen removal rate by increasing the abundance of nitrogen-converting functional microbes and the genes associated with nitrification and denitrification.

Effects of Nitrogen Input and Aeration on Greenhouse Gas Emissions and Pollutants in Agricultural Drainage Ditches

Understanding the patterns of greenhouse gas emissions and the changes in pollution load in terrestrial freshwater systems is crucial for accurately assessing the global carbon cycle and overall greenhouse gas emissions. However, current research often focuses on wetlands and rivers, with few studies on agricultural drainage ditches, which are an important part of the agricultural ecosystem. Investigating the greenhouse gas emission patterns and pollution load changes in agricultural drainage ditches can help accurately assess the greenhouse effect of agricultural systems and improve fertilization measures in farmlands. This study explored the effects of nitrogen input and aeration on the pollution load and greenhouse gas emission processes in paddy field drainage ditches. The results showed that aeration significantly reduced the concentration of ammonium nitrogen (NH4+) in the water, decreased the emissions of nitrous oxide (N2O) and methane (CH4), and slightly increased the emission of carbon dioxide (CO2), resulting in an overall reduction of the global warming potential (GWP) by 34.02%. Nitrogen input significantly increased the concentration of ammonium nitrogen in the water, slightly reduced the emissions of N2O and CH4, and increased the CO2 emissions by 46.60%, thereby increasing the GWP by 15.24%. The drainage ditches reduced the pollution load in both the water and sediment, with the overall GWP downstream being 9.34% lower than upstream.

Changes in chemical fractionation of copper and zinc in soil as a function of incubation moisture content and organic matter amendments

Copper and zinc are essential micronutrients that are potentially toxic when present in excess in soils. Their bioavailability depends on their speciation in soil, but this may vary with environmental conditions. Aeration and hence redox conditions, and organic matter amendments are among the factors likely to cause variation on metal fractionation. We have monitored the chemical fractionation of both native and added copper and zinc in a clay loam top soil during a 5-month laboratory incubation. The effects of aeration (moist soil or flooded) and addition of two organic matter amendments, alfalfa straw or leaf compost, were studied. Metal spike was more labile than legacy metal, and was slowly redistributed over the incubation period. Organic matter caused short-lived flushes of metals, attributed to metal chelation with soluble organic matter. This effect was greater for straw than for more stable compost. There was no evidence that added organic matter increased the capacity of soil organic matter to immobilise metal. Flooding solubilized soil metal (hydr)oxides, releasing legacy Cu and Zn, but with less effect on the capacity to immobilise metal spike. Effects of flooding and organic matter addition were not additive. Both metals appear to be precipitated as sulphides under reducing conditions, and accounted for in the acid soluble phase. Monitoring the dynamics of metal distribution gives a more comprehensive understanding of underlying processes than would a single measurement, and is closer to in campo conditions than slurry microcosms.

Effect of pure oxygen aeration on soluble microbial products production in activated sludge system under the toxic condition of phenol

Soluble microbial products (SMP) contribute most of effluent organic matter (EfOM) in biological treatment processes. These products cause membrane fouling and generate disinfection by-products. This study investigated the effect of pure oxygen aeration on the production and characteristics of SMP under the toxic condition of phenol. Two sequencing batch reactors with pure oxygen (O-SBR) and air (A-SBR) aeration were used in the experiments. Results showed that the effluent chemical oxygen demand values of O- and A-SBR were 36.11 ± 1.54 and 42.44 ± 1.42 mg/L, respectively. SMP was the dominant component of EfOM. The various aeration types caused differences in the contents of extracellular polymeric substances (EPS) and SMP in the two SBRs. The content of loosely bound EPS (LB-EPS) in A-SBR was higher than that in O-SBR by 25%, whereas the tightly bound EPS content in A-SBR was lower than that in O-SBR by 19%. Pure oxygen aeration decreased 15% of humic acids, 42% of polysaccharides, and 29% of protein contents of SMP compared with air aeration, but it did not change the functional groups of SMP. SMP concentration was positively correlated with LB-EPS. Pure oxygen aeration caused the low contents of LB-EPS and SMP. This study showed the effect of pure oxygen aeration on SMP reduction, which can be useful for toxic industrial-wastewater biological treatment.

Különböző gyepkezelések hatásának cönológiai és természetvédelmi vizsgálati eredményei üde gyepen

In grassland management systems, the various agrotechnical elements have to be used in many cases on "primitive grasslands", where the coordination of agricultural and nature conservation tasks is necessary. Here, animal husbandry is the main aspect, which includes the long-term preservation of the quality of the pasture, as well as the most economical use of the pasture and keeping the animals as cheap as possible. The tests were carried out on a grassy area on the border of the settlement of Aba. We examined the vegetation of 8 plots of the same size in the area and the quantitative and qualitative composition of the biomass produced there. In this thesis, we provide data on the vegetation composition and evaluation of the following treatments. The plots and treatments were as follows: I. plot-ventilated; II. parcel-relaxed; III. plot loosened and ventilated; ARC. parcel control; V. plot-ventilated and 15 t/ha manure; VI. plot loosened and 15 t/ha manure; VII. plot loosened, ventilated and 15 t/ha manure; VIII. plot loosened, ventilated and 30 t/ha manure. In each plot, 5 ceenological recordings were made using 4 x 4 m quadrats. The estimated coverage of each species was given in %, taking into account the proportion of grasslands and other species. Among Borhidi's plant ecological indicators, the species were evaluated based on the NB (relative values of nitrogen demand) and WB (relative soil water and soil moisture indicator numbers). The social behavior types (SZMT) were also defined based on Borhidi's work, and the nature conservation value categories (TVK) were defined according to Simon. The lifestyle analysis was performed based on Pignatti's lifestyle types. Based on the data, the composition of the vegetation of each plot changed significantly compared to the data of the control plot IV. A direct proportionality can be discovered between the increase in the cover value of the dominant lawn grasses, primarily Festuca arundinacea, Dactylis glomerata, Alopecurus pratensis, and Fabaeceae species (e.g. Lathyrus tuberosus, Lotus corniculatus) and the amount of applied nutrients. Based on the coenological survey of the eight examined areas, the control area (IV.) showed the most natural state, which was confirmed by the species composition and number of species. The IV. plots are close to I., II. and III. for plot recordings, which proves that aeration and loosening do not worsen the condition of the lawn, but rather promote the preservation of its natural state. The VII-VIII. plots have the smallest number of species, but based on the life form spectrum, naturalness indicators, nature conservation value categories and social behavior types, they are not very disturbed habitats. No significant difference can be detected between the effect of lawn loosening and lawn aeration, but III. plot, where both treatments were carried out, was closer to the control area. Regarding the effect of the lawn management methods, it was possible to produce a starting data set in the long term (with the same environmental conditions). Overall, the study gave valuable results regarding the age of change occurring during the application of different lawn management methods, and was also effective from an economic point of view.

Observation of Excess Air Discharge in the Budikdamber Pond Aeration System on the Real Effect of Tilapia Fish Health (Oreochromis spp.)

DO levels are needed by fish organisms for metabolic processes, so the value changes quickly. So, giving aeration all the time and siphonization every day is the best treatment in maintaining water quality for growth. However, a study revealed that there is a negative side to excessive aeration until it reaches a saturation point. The results of the study on the process and level of exposure related to gas bubble disease caused by hyperoxia. The first symptom is the presence of gas bubbles under the skin, gas bubbles appear on most of the fins, along the lateral line, gills and in the eyes. Currently, another research is being conducted to prove the real effect of excess aeration, specifically on the health of Tilapia in closed ponds at normal ambient temperatures. In the closed water pond system, air flow is given at 25 mg/L (first pool), 40 mg/L (second pool), and 54 mg/L (third pool), with variable treatment of feed, water quality (temperature &amp; pH). , and the same volume. The focus of the type of fish that will be observed in this research is Tilapia, with a duration of observation for ± 1 month. The maximum DO measurement results at a normal ambient temperature of 25.6 °C pool water is 8.2 mg/L. The optimum DO level in the first pond that is aerated with an air flow of 25 L/m is ± 7.9 mg/L, the optimum DO level in an aerated pond with an air flow of 40 L/m is ± 8.1 mg/L, and the optimum DO level in an aerated pond with an air flow rate of 54 L/m is ± 8.1 mg/L. No matter how big the air flow from the aerator is put into the water, the DO level will not exceed the value of 8.2 mg/L as long as the water temperature is not lower than 25 °C. Tilapia in ponds containing the highest DO levels at normal ambient temperature conditions of this pond water (24.4 – 25.9 °C), grows and develops very well, in fact there is no adverse effect on health.

Effect of hydrodynamic aeration on bioelectricity generation from photoautotrophic Spirulina platensis in biophotovoltaic devices

A biophotovoltaic (BPV) device is a type of bioelectrochemical cell that shows potential for renewable energy production using photosynthetic exoelectrogenic microorganisms. However, the technology currently has limitations due to its relatively low power output and high dependence on biofilm attachment. Thus, this paper examines the effect of hydrodynamic aeration on the bioelectricity generation of BPV devices. Aeration is widely applied in microalgae cultivation to improve the mixing effect between microalgae cells, culture medium, and air bubbles. The methodology involves the cultivation of Spirulina platensis, device fabrication, voltage measurement in both non-aeration and aeration modes, and the use of polarization curves to determine the device performance under a gradually rising external load. The BPV devices are affected by abnormal voltage drop under high external loads, which is called power overshoot. The use of aeration successfully solved the power overshoot issues over time, but it also resulted in a gradual reduction in the voltage output and power density of the BPV devices. During aeration, the BPV devices produced a peak power density of 0.121 ± 0.056 mWm−2 on Day 1, which declined to 0.048 ± 0.025 mWm−2 on Day 13. The blowing of air bubbles had some side effects on BPV devices, including causing the attachment of Spirulina cells to the container walls and accelerating the evaporation of the culture medium. This study emphasizes the role of hydrodynamic aeration in the bioelectricity generation process and opens up possibilities for wider application of BPV devices in renewable energy production.

Enhanced in situ production of Fenton reagent's by nanobubble aeration and sacrificial iron anodes in the electro-Fenton process

Wastewater treatment is currently focused on the development of simple, safe, cost-effective technologies for the complete destruction of persistent organic pollutants. A novel reagent-free electro-Fenton process by integrated nano-bubble aeration and sacrificial iron anode is proposed, which improves mass transferability of large content dissolved oxygen (10.55mgL−1) in the electrolyte and then quickly transported oxygen to the electrode surface. The synergistic effect of nanobubble aeration and sacrificial iron anodes can product a highly efficient hydrogen peroxide (H2O2) (310 mgL−1) and enhanced electrochemically driven reduction of Fe2+ at pH 3.5 and current density 55 mAcm−2. The degradation of phenol (100 mgL−1) with hydroxyl radicals (⋅OH) generated in situ is described by a pseudo first-order kinetics mode and was fast (0.036 min−1), which obtained a remarkable decolorization of over 58.7 % in 60 min. With nanobubble aeration and sacrificial iron anode, the catalytic decomposition of H2O2 to ⋅OH by Fe2+ was more powerful, achieving a cost-effective and green design without reagents.

On the effect of aeration on laser ranging measurements of free water surface

Aerated flows pose both challenges and opportunities in the measurement of free water surface. In this study, an amplitude-modulated continuous wave scanning LIDAR device was used to measure a distance from the device sensor to the water column surface subjected to different degrees of aeration, while reference measurements were performed by high-speed imaging. Different aeration conditions were generated by variation of the air flow rate supplied to the liquid and by using perforated plates with different hole arrangements. The LIDAR device was shown to produce level readings consistently below visible water levels. The measurement error of the LIDAR method is largely determined by the volume fraction of air in water and was lowest at about 0.1 air volume fraction. The error increases linearly until a very high air volume fraction (i.e., above 0.55), while the LIDAR method also performs poorly in unaerated water. Although the measurement uncertainty of LIDAR in the range of aerated water is by at least an order of magnitude higher than in the case of measuring dry solid surfaces, the method is viable for free surface measurement under low to moderate aeration conditions that don't produce excessive foaming.