IMPACT OF STATIC MAGNETIC FIELD ON EFFICIENCY OF FINE-BUBBLE AERATION OF LIQUID

Aeration is the main item in the operating costs of most wastewater treatment plants. New, efficient methods of aeration are constantly requested. Even a small increase in the efficiency on the larger scale of the process provides significant financial savings. The paper presents the possibility of increasing the efficiency of oxygen transfer through the use of a static magnetic field. The aim of the study was to evaluate impact of static magnetic field on efficiency of fine-bubble aeration of liquid. The experiment were conducted in constant temperature (24°C) at pH 8.25. The aeration intensity was 58 L/h. The mean magnetic field induction ranged from 10 mT in a series 1, to 14 mT in a series 2 and 16 mT in a series 3. The OC value in case of the use of the lowest induction was 75.22 g/(m3•h). In series 2 the OC value was an average of 77.7 g/(m3•h). In series 3, when magnetic field with the highest induction was used, the OC value was 92.72 g/(m3•h). While in the control series, without the use of static magnetic field, the OC was only 60.5 g/(m3•h). Positive experiments results in laboratory scale tent to research on possibility for application of static magnetic field to enhance the efficiency of aeration in industrial devices

Inhibition of Methane Fermentation by Antibiotics Introduced to Municipal Anaerobic Sludge

Annually, a few thousand tons of antibiotics and their transformation products (metabolites and degradation products) are introduced to wastewater treatment plants (WWTPs) as a result of human and animal excretion, or dispose of expired or unused medications. Antibiotics present in wastes might inhibit their treatment processes for instance during methane fermentation. In this study, β-lactams, tetracycline’s, fluoroquinolones, sulphonamides and metronidazole were selected as inhibitors of methane fermentation of sewage sludge collected from municipal WWTP. The experiments were performed in two series with different concentrations of antibiotics. The biogas production did not significantly differ between series, and was from 151.7 ± 18.9 mL/g VS (in the bioreactor with metronidazole addition—II series) to 208.3 ± 11.9 mL/g VS (in the bioreactor with amoxicillin addition—I series). In the control sample biogas production was 203.7 ± 21.1 mL/g VS. The methane content in all experiments was from 61.3 ± 2.1% to 66.4 ± 3.1%. The results indicated that microorganisms in anaerobic sludge from municipal wastewater are highly resistant to antibiotics in the tested concentrations. Antibiotic present in wastewater probably caused of antibiotic resistance in bacteria

IMPACT OF STATIC MAGNETIC FIELD ON EFFICIENCY OF FINE-BUBBLE AERATION OF LIQUID

Aeration is the main item in the operating costs of most wastewater treatment plants. New, efficient methods of aeration are constantly requested. Even a small increase in the efficiency on the larger scale of the process provides significant financial savings. The paper presents the possibility of increasing the efficiency of oxygen transfer through the use of a static magnetic field. The aim of the study was to evaluate impact of static magnetic field on efficiency of fine-bubble aeration of liquid. The experiment were conducted in constant temperature (24°C) at pH 8.25. The aeration intensity was 58 L/h. The mean magnetic field induction ranged from 10 mT in a series 1, to 14 mT in a series 2 and 16 mT in a series 3. The OC value in case of the use of the lowest induction was 75.22 g/(m3•h). In series 2 the OC value was an average of 77.7 g/(m3•h). In series 3, when magnetic field with the highest induction was used, the OC value was 92.72 g/(m3•h). While in the control series, without the use of static magnetic field, the OC was only 60.5 g/(m3•h). Positive experiments results in laboratory scale tent to research on possibility for application of static magnetic field to enhance the efficiency of aeration in industrial devices

Removal of CO₂ from Biogas during Mineral Carbonation with Waste Materials

Biogas represents a source of renewable energy that could provide a replacement for fossil fuels to meet the increasing demand for energy. The upgrading of biogas through the removal of CO2 to a content of 95–97% of CH4 is necessary to increase its calorific value. This review focuses on biogas upgrading technologies using wastes or residues that enable the performing of mineral carbonation. In this research, we analyzed a natural biogas or synthetic one with a content of about (40–50%) of carbon dioxide. The chemical absorption is also briefly described in this study, due to its being the first step in innovative absorption and regeneration processes using mineral carbonization. Wastes with high calcium contents, i.e., ashes, steel-making slags, and stabilized wastewater anaerobic sludge, were considered for direct carbonization, taking into account the leaching of particles from carbonated wastes/residues. Moreover, the different types of reactors used for mineral carbonation have been described. The presented technological solutions are easy to use and economical, and some of them also take into account the regeneration of reagents. However, in the context of their direct use in biogas plants, it is necessary to consider the availability of wastes and residues

Enhancement of sedimentation and coagulation with static magnetic field

The static magnetic field can be an alternative method for wastewater treatment. It has been proved that this physical factor, accelerates the biochemical processes, catalyzes advanced oxidation, intensifies anaerobic and aerobic processes or reduces swelling of activated sludge. There are also reports proving the positive impact of the static magnetic field on the coagulation and sedimentation, as well as the conditioning and dewatering of sludge. In order to be applied in larger scale the published results should be verified and confirmed. In the studies, the enhancement of sedimentation by the static magnetic field was observed. The best sedimentation was noted in the experiment, where magnetizers were placed on activated sludge bioreactor and secondary settling tank. No effect of the static magnetic field on coagulation with the utilization of PIX 113 was observed. However, the static magnetic field enhanced coagulation with the utilization of PAX-XL9. The results suggest that increased sedimentation of colloids and activated sludge, can in practice mean a reduction in the size of the necessary equipment for sedimentation with an unchanged efficiency of the process

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

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

Effect of Inorganic Coagulants on the Characteristics in Anaerobic Digested Distillery Stillage Valorization

The aim of the study was to determine the possibility of using coagulation for treatment of anaerobically digested distillery stillage. Post-fermentation sludge from waste product of bioethanol production is usually drained. Then, condensed sediments are directed as a fertilizer for arable fields. The remaining liquid phase due to the high content of organic compounds cannot be discharged to environment. The study used inorganic salts of iron and aluminum as coagulants to treatment liquid fraction obtained after methane fermentation of distillery stillage. In valorization process, the reduction of organic compounds and suspended solids was not sufficient. The highest doses of coagulants reduced COD concentration of about 80% and lower the pH of the solution. However, the dose 10 mL/L is not economically profitable and due to concentration of aluminum or iron it is too harmful for environment

Biogas potential of digestate after fermentation of Sida hermaphrodita silage

Lignocellulosic biomass is one of the most widely used substrate in methane digestion. Among plants with a high yield potential, Sida hermaphrodita is particularly noteworthy, due to Sida can be grown on low quality soils and its utilization for energy purposes is not competitive with food crops. Methane fermentation of biomass with such a complex structure usually requires application of pretreatment methods for efficient utilization of its cellulose and hemicellulose. It is economically justified to control of digestate if substrate was efficiently used. The study aimed to measure biogas potential of digestate after fermentation of Sida hermaphrodita silage. The post-fermentation of two samples of digestate from the reactors operated at organic compounds loading 2 kg/(m3 ∙d) – S1 and 3 kg/(m3 ∙d) – S2 was performed. Hydraulic retention time in these reactors was 50 d and 33 d, respectively. Biogas potential of fermented sludge was measured with the use of AMPTS II (Bioprocess control). Biogas production was 0.012 L/g TS and 0.031 L/g TS from digestate’s S1 and S2, respectively. The methane content in biogas was 15% from digestate S1 and 50% from digestate S2. The obtained results suggest that digestate from reactor with organic compounds loading of 3 kg/(m3 ∙d) still has high biogas potential, and hydraulic retention time in this reactor should be prolonged