Packing Media Research Articles

Performance evaluation of a hybrid treatment system for the treatment of grey water

ABSTRACT The performance of a combined up-flow submerged aerated biological filter (SABF) and photocatalytic process (PC) for the treatment of grey water was studied. The removal of COD, hardness, alkalinity, and turbidity was considered. The removal efficiency of SABF using organic and inorganic packing materials was evaluated. The combined SABF and PC removed 100% of COD, up to an organic loading rate (OLR) of 0.21 ± 0.05 kg/m3/day at 12 h HRT, irrespective of the packing media. The fibrous outer shell of coconut fibres favoured turbidity removal, but both the organic and inorganic packing materials showed equal performance in the removal of physicochemical parameters of the grey water.

Performance evaluation of species varied fixed bed biofilm reactor for wastewater treatment of Dhobi Khola outfall, Setopul, Kathmandu, Nepal

The sustainability of wastewater treatment plants poses significant challenges for developing countries, necessitating substantial investment for operation and maintenance. Biofilm reactors seeded with specific species of microorganisms were investigated under controlled environmental conditions. However, the performance evaluation of such reactors under natural conditions remains largely underexplored. This study investigated wastewater treatment capabilities of bench-scale fixed bed biofilm reactors, employing various species (Wastewater Microbes, Pseudomonas, Algae, and a co-culture of Algae and Pseudomonas). The reactors (Treatments and Control) were filled with 28 mm nominal-size local aggregates as packing media, operated under different contact times, and subjected to varying concentrations of heavy metals (Zn, Cd). To assess the reactor performances, the Bland-Altman Plot and Chemical Oxygen Demand (COD) removal kinetics were evaluated.The results revealed that the reactor initiated with a co-culture exhibited the optimal COD removal efficiency, reaching 84 ± 1 %. The reactor initially seeded with wastewater microbes exhibited the highest heavy metal elimination, achieving 94 ± 1 % and 88 ± 1 % removal for Zn and Cd respectively. The wastewater-seeded reactor demonstrated the zero-order COD removal kinetic coefficient (k) of 46.41 mg/L/h at an average influent COD concentration of 558 mg/L at 10 h contact time. While Pseudomonas-seeded reactor demonstrated k = 0.73 mg/L/h at 20 h contact time with 69 mg/L influent COD and heavy metal concentrations Zn = 26 mg/L and Cd = 3.57 mg/L.The findings of this study suggest that variations in environmental conditions, contact time, and heavy metal concentration have minimal impact on the pollutant removal efficacy of the reactors, and provide robust evidence for their viability as a sustainable alternative in municipal wastewater treatment. The study also identifies the possibility of treating specific wastewater characteristics by altering the dominant species in the reactors, paving the way for further research on the efficacy of other microbial genomes in fixed bed biofilm reactors.

Influence of Cuttlefish-Ink Extract on Canned Golden Seabream (Sparus aurata) Quality.

Four different concentrations of an aqueous extract of cuttlefish (Sepia spp.) ink (CI) were introduced, respectively, into the packing medium employed during golden seabream (Sparus aurata) canning. The quality parameters of the resulting canned fish were determined and compared to the initial fish and the control canned muscle. An important effect of the CI concentration introduced in the packing medium was proved. The presence in the packing medium of a relatively low CI concentration (CI-2 batch) led to a lower (p < 0.05) lipid oxidation development (fluorescent compound formation), lower (p < 0.05) changes of colour parameters (L* and a* values), and lower (p < 0.05) trimethylamine values in canned fish when compared to control canned samples. Additionally, the two lowest CI concentrations tested led to higher average values of C22:6ω3, ω3/ω6 ratios, and polyene index. On the contrary, the use of the most concentrated CI extract (CI-4 condition) led to a prooxidant effect (higher fluorescence ratio value). In agreement with environmental sustainability and circular economy requirements, the study can be considered the first approach to a novel and valuable use of the current marine byproduct for the quality enhancement of canned fish. On-coming research focused on the optimisation of the CI-extract concentration is envisaged.

A comparative study on performance of the conventional and fixed-bed membrane bioreactors for treatment of Naproxen from pharmaceutical wastewater

Here, a comparative study was designed to survey the treatment efficiency of pharmaceutical wastewater containing Naproxen by Membrane bioreactor (MBR) and MBR with fixed-bed packing media (FBMBR). To this end, the performance of MBR and FBMBR in different aeration conditions including average DO (1.9–3.8 mg/L), different organic loading (OLR) (0.86, 1.14 and 1.92 kg COD per cubic meter per day), and Naproxen removal efficiency. The BOD5 removal efficiency, effluent quality and membrane fouling were monitored within 140 days. The results obtained from the present study indicated that COD removal efficiency for FBMBR (96.46%) was higher than that for MBR (95.33%). In addition, a high COD removal efficiency was experienced in both MBR and FBMBR in operational conditions 3 and 4, even where OLR increased from 1.14 to 1.92 kgCOD/m3 d and DO decreased from 4 to < 1 mg/L. Furthermore, the higher Naproxen removal efficiency was observed in FBMBR (94.17%) compared to that for MBR (92.76%). Therefore, FBMBR is a feasible and promising method for efficient treatment of pharmaceuptical wastewater with high concentrations of emerging contaminant, especially, the Naproxen.

Assessment of Potential Use of a Composite Based on Polyester Textile Waste as Packing Elements of a Trickle Bed Bioreactor.

Biological wastewater treatment using trickle bed reactors is a commonly known and used solution. One of the key elements of the proper operation of the trickle bed bioreactor is the appropriate selection of biofilm support elements. The respective properties of the bioreactor packing media used can influence, among other things, the efficiency of the treatment process. In this study, the possibility of polyester waste material usage for the preparation of the biofilm support elements was tested. The following properties were checked: adsorption capacity, swelling, surface morphology, microbicidal properties, as well as the possibility of their use in biological wastewater treatment. The tested elements did not adsorb copper nor showed microbicidal properties for bacterial strains Escherichia coli and Staphylococcus aureus as well as fungal strains Aspergillus niger and Chaetomium globosum. The hydrophilic and rough nature of the element surface was found to provide a friendly support for biofilm formation. The durability of the elements before and after their application in the biological treatment process was confirmed by performing tests such as compressive strength, FTIR analysis, hardness analysis and specific surface area measurement. The research confirmed the applicability of the packing elements based on polyester textile waste to the treatment of textile wastewater. The treatment efficiency of the model wastewater stream was above 90%, while in the case of a stream containing 60% actual industrial wastewater it was above 80%. The proposed solution enables the simultaneous management of textile waste and wastewater treatment, which is consistent with the principles of a circular economy. The selected waste raw material is a cheap and easily available material, and the use of the developed packing elements will reduce the amount of polyester materials ending up in landfills.

Evaluation of the use of a biofilter made with biodegradable material for biogas desulfurization

Biogas is a promising energy source with the potential to contribute to greenhouse gas emission reduction. In addition, it can be produced from waste biomass and has various applications. However, contaminants have to be removed before use. Hydrogen sulfide (H2S) is perhaps the most critical because of its toxicity and corrosive properties. In this study, we evaluated a prototype of a biofilter for biogas desulfurization made of coconut chips as packing media and digester effluent as a nutrient source. The composition of inlet and outlet biogas was evaluated through gas chromatography in five tests. The maximum desulfurization efficiency observed was 75.80%, but with a considerable variation (mean of 43.08%). Microscopy analysis of the packing media before and after the experiments demonstrated the accumulation of substances and the presence of new elements. Nevertheless, more studies are necessary with longer duration and frequency for a better evaluation of the system stability and saturation.

Research and Development of the Treatment Effectiveness of a Novel Process for Vegetable Biogas Slurry Purification

Nowadays, an anaerobic filter is used in treating various wastewaters that is more effective for denitrification and organic removal. The Anaerobic Filter with Inoculum, Soft and Hard Packing Medium (AFISH) and Double-Filling Aerobic Baffle (DFAB) reactors were continuously operated for 120 days with a short Hydraulic Retention Time (HRT) in the range of 1 and 2 days at an Organic Loading Rate (OLR) of 0.58 and 1.08 gCOD/(l.d) by daily feeding the influent Chemical Oxygen Demand (COD) concentration between 1169 and 250 mg/l. After treating the sample wastewater in the new AFISH reactor, the effluent flowed into the DFAB reactor for further treatment to determine the treatment effectiveness of the novel AFISH and DFAB reactors at a short HRT of 1 to 2 days. The influent COD was reduced to 376 mg/l to 250 mg/l in a novel AFISH effluent and further dropped to 220 mg/l to 102 mg/l following DFAB reactor treatment. The COD removal in the AFISH reactor was around 67% when HRT was about 1 day, and a high COD value of 78% was removed during the HRT of 2 days, while in the DFAB reactor, the capability of treatment reached between 40% and 57% of the COD removed at the HRT of 1 and 2 days. The concentration of NH4-N in the effluent of the novel AFISH reactor was significantly lower than the effluent of the DFAB reactor, with NH4-N concentrations ranging from 157 mg/l to 330 mg/l. However, the treatment of vegetable bio-slurry from the Internal Circulation (IC) reactor by the novel AFISH and DFAB reactors satisfied the secondary wastewater discharge standard in the Integrated Wastewater Discharge Standard. Therefore, this novel process is one method beneficial for current and further research development that can be applied for industrial wastewater treatment processing and provides science information to those interested in research in the future.

Coconut husks as a packing media in anaerobic filters for the treatment of septic tank effluent in Tonga

Septic tanks can become overloaded overtime due to increases in the size of households or the build-up of sludge. This results in the wastewater spending less time within the tank and therefore a reduced level of treatment. One solution to enhance treatment is to add an anerobic filter after the existing septic tank. The anaerobic filter requires media for the establishment of a biofilm and the use of coconut husks were identified as a possibility due to their abundance. Both green and brown coconut husks were imported from Tonga and tested in laboratory scale anerobic filters treating synthetic wastewater. The treatment performance was monitored in terms of the chemical oxygen demand (COD) which is a measure of organic strength. There was also potential for organic material to leach out of the coconut husks so additional testing was done to evaluate this. It was found that four times more COD was leached from the green coconut husks showing that brown coconut husks were the better choice. The brown coconut husk reactor reduced the COD concentration by 49%. This study has indicated that there is value in examining the feasibility of implementing an anaerobic filter using brown coconut husks to enhance wastewater treatment from septic tanks. Further research should focus on examining whether any nutrients are released from the husk and then practical considerations such as the scale needed for a household and maintenance requirements.

Nitrogen-sparging assisted anoxic biological drinking water treatment system.

Existing heterotrophic denitrification reactors rely on microorganisms to consume dissolved oxygen (DO) and create conditions suitable for denitrification, but this practice leads to excessive microbial growth and increased organic carbon doses. An innovative reactor that uses nitrogen gas sparging through a contactor to strip DO was developed and tested in the lab. It reduced influent nitrate from 15 to <1 mg/L as N with nitrite accumulation <1 mg/L as N. It maintained a consistent flow rate and developed minimal headloss, making it easier to operate than the denitrifying dual-media filter that was operated in parallel. Gravel, polyvinyl chloride pieces, and no packing media were assessed as options for the nitrogen-sparged contactor, and gravel was found to support denitrification at the highest loading rate and was resilient to nitrogen-sparging shutoffs and intermittent operation. This innovative reactor appears promising for small drinking water systems.

Effect of packing media type of moving and fixed on performance and membrane fouling in biofilm-based MBR processes

Effect of packing media type of moving and fixed on performance and membrane fouling in biofilm-based MBR processes

Plugging Experiments on Different Packing Schemes during Hydrate Exploitation by Depressurization

Marine natural gas hydrate (NGH) can mainly be found in argillaceous fine-silt reservoirs, and is characterized by weak consolidation and low permeability. Sand production is likely to occur during the NGH production process, and fine-silt particles can easily plug the sand-control media. In view of this, experiments were conducted to assess the influence of the formation sand on the sand retention media in gravel-packed layers under gas–water mixed flow, and the plugging process was analyzed. The results show that following conclusions. (1) The quartz-sand- and ceramic-particle-packed layers show the same plugging trend, and an identical plugging law. The process can be divided into three stages: the beginning, intensified, and balanced stages of plugging. (2) The liquid discharge is a key factor influencing the plugging of gravel-packed layers during NGH exploitation by depressurization. As the discharge increases, plugging occurs in all quartz-sand packing schemes, while the ceramic-particle packing scheme still yields a high gas-flow rate. Therefore, quartz sand is not recommended as the packing medium during NGH exploitation, and the grain-size range of ceramic particles should be further optimized. (3) Due to the high mud content of NGH reservoirs, a mud cake is likely to form on the surface of the packing media, which intensifies the bridge plugging of the packed layer. These experiment results provide an important reference for the formulation and selection of sand-control schemes.

FexO/FeNC modified activated carbon packing media for biological slow filtration to enhance the removal of dissolved organic matter in reused water

The biological slow filtration reactor (BSFR) process has been found to be moderately effective for the removal of refractory dissolved organic matter (DOM) in the treatment of reused water. In this study, bench scale experiments were conducted using a mixture of landscape water and concentrated landfill leachate as feed water, to compare a novel iron oxide (FexO)/FeNC modified activated carbon (FexO@AC) packed BSFR, with a conventional activated carbon packed BSFR (AC-BSFR), operated in parallel. The results showed that the FexO@AC packed BSFR had a refractory DOM removal rate of 90%, operated at a hydraulic retention time (HRT) of 10 h at room temperature for 30 weeks, while under the same conditions the removal by the AC-BSFR was only 70%. As a consequence, the treatment by the FexO@AC packed BSFR substantially reduced the formation potential of trihalomethanes, and to a less extent, haloacetic acids. The modification of FexO/FeNC media raised the conductivity and the oxygen reduction reaction (ORR) efficiency of the AC media to accelerate the anaerobic digestion by consuming the electrons that are generated by anaerobic digestion itself, which lead to the marked improvement in refractory DOM removal.

An integrated Lattice-Boltzmann model of immiscible two-phase flow and bulk mass transfer with Marangoni effect

The microscale reactive immiscible multiphase flow often happens for the miniaturized chemical reactor such as micro fixed-bed-reactor, but it is significantly challenging in solving concurrently hydrodynamic, mass transfer and reaction behaviors in the porous packing media. Based on the phase-field (PF) and the revised Fick's law mass transfer approaches, a new multicomponent-multiphase Lattice-Boltzmann (LB) model with chemical reaction and the Marangoni effect was built up. Both the bulk homogeneous and fluid-solid interface heterogeneous reactions were resolved for the reactive two-phase fluid. The curved boundary treatment in Cartesian grids was upgraded to describe the heterogeneous reaction in the LB framework. Those mathematical models were validated respectively and showed good agreement with the analytical solutions. Then we applied our new models in the vortex flow field in a micro-structured reactive substrate. The numerical results showed that the newly developed LB model is able to simulate reactive multiphase flow in micro-structured porous media, which can provide a strong basis for future industrial applications.

Enhancement of Lipid Stability and Acceptability of Canned Seafood by Addition of Natural Antioxidant Compounds to the Packing Medium-A Review.

Seafoods are known to include high contents of valuable constituents. However, they are reported to be highly perishable products, whose quality rapidly declines post-mortem, thus demanding efficient processing and storage. Among the traditional technologies, canning represents one of the most important means of marine species preservation. However, owing to the thermal sensitivity of the chemical constituents of marine species, remarkable degradative mechanisms can be produced and lead to important quality losses. The demand for better quality food makes the need for advanced preservation techniques a topic to be addressed continually in the case of seafood. One such strategy is the employment of preservative compounds obtained from natural resources. The current review provides an overview of the research carried out concerning the effect of the addition of bioactive compounds to the packing medium on the thermal stability of canned seafood. This review addresses the preservative effect of polyphenol-rich oils (i.e., extra virgin olive oil) and different kinds of products or extracts obtained from plants, algae and seafood by-products. In agreement with the great incidence of lipid damage on the nutritional and acceptability values during high-temperature seafood processing, this work is especially focussed on the inhibitory effect of lipid oxidation development.

Use of Shredded Recycled Plastic as Filter Bed Packing in a Vertical Flow Filter for Onsite Wastewater Treatment Plants: Preliminary Findings

Household wastewater is a problem, especially in areas with a dispersed settlement where there is no wastewater collection system or wastewater treatment plant. In this case, it is necessary to build a local or onsite wastewater treatment plant. This paper is an attempt to analyse the possibility of using recycled shredded ABS plastic (acrylonitrile butadiene styrene) as packing media in an experimental vertical flow filter for use in on-site wastewater treatment plants. Studies have shown that shredded recycled ABS is a promising filtration material that has several features important in the treatment process, like a large surface area, high mechanical strength and chemical inertness. The system was operated with a hydraulic load of 50 dm3/m2 (3 months). BOD5 (biochemical oxygen demand), COD (chemical oxygen demand), and total suspended solids (TSS) reduction efficiency in the primary effluent was high; 94.4%, 77.8%, and 92.8%, respectively.

Removal of Methylene Blue dye from textile wastewater using vertical flow constructed wetland

The aim of this study is to assess the performance of vertical flow constructed wetland system to treat synthetically prepared textile wastewater containing Methylene Blue dye (MB) of two different dye concentrations of 50 mg/L and 100 mg/L. Three lab scale Vertical Flow Constructed Wetland systems (CW1, CW2 and CW3) of size 30 cm diameter and 60 cm depth each were fabricated. CW1, acted as a control system without plants and was packed with sand, zeolite and gravel. CW2 and CW3 were planted with wetland plants - Canna Indica. CW2, was filled with packing media: sand, zeolite and gravel and CW3, with sand and gravel. The wetlands were operated in batch and continuous mode. The systems were evaluated by measuring Colour removal, Chemical Oxygen Demand (COD), pH and Electrical Conductivity (EC). The absorbance of the Methylene Blue dye in the wastewater before and after treatment was measured at the wavelength of maximum absorption using UV/visible spectrophotometer. The results showed that the wetlands CW1, CW2 and CW3 reduced colour by 85 %, 93 % and 74 % for 50 mg/L of MB and 89 %, 99 % and 74 % respectively for 100 mg/L of MB. COD removal of 70 %, 93 % and 89 % was achieved in CW1, CW2 and CW3 respectively for 50 mg/L MB. At 100 mg/L MB, COD removal was 65 %, 89 % and 83 % in CW1, CW2 and CW3 respectively. This study shows that the constructed wetland system with zeolite is a promising technique for the colour removal of methylene blue dyeing textile effluents.

Application of different packing media for the biofiltration of gaseous effluents from waste composting

ABSTRACT A pilot-scale experiment was implemented in a waste bioreactor with an inner capacity of 1 m3 in order to simulate a real-scale composting process. The waste underwent composting conditions that are typical of the initial bio-oxidation phase, characterised by a high production of volatile organic compounds (VOCs), hydrogen sulphide (H2S) and odorants. The waste bioreactor was fed with an intermittent airflow rate of 6 Nm3/h. The target of this study was to investigate the air treatment performance of three biofilters with the same size, but filled with different filtering media: (1) wood chips, (2) a two-layer combination of lava rock (50%) and peat (50%), and (3) peat only. The analyses on air samples taken upstream and downstream of the biofilters showed that the combination of lava rock and peat presents the best performance in terms of mean removal efficiency of odour (96%), total VOCs (95%) and H2S (77%) concentrations. Wood chips showed the worst abatement performance, with respective mean removal efficiencies of 90%, 88% and 62%. From the results obtained, it is possible to conclude that the combination of lava rock and peat can be considered as a promising choice for air pollution control in waste composting facilities.

Effect of Previous Frozen Storage, Canning Process and Packing Medium on the Fatty Acid Composition of Canned Mackerel.

This study addressed the fatty acid (FA) composition of canned Atlantic mackerel (Scomber scombrus). In it, the effect of prior frozen storage (6 months at -18 °C), different packing media (water, brine, and sunflower, refined and extra virgin olive oils), and canning procedure was investigated. As a result, the canning procedure led to a decrease (p &lt; 0.05) in saturated FA (STFA) levels, an increase (p &lt; 0.05) in polyunsaturated FA (PUFA) and total ω3 FA values, and higher PUFA/STFA and ω3/ω6 ratio values. Concerning the packing medium effect, the great presence of C18:2ω6 in sunflower oil led to high PUFA and PUFA/STFA values and low ω3/ω6 ratios when compared to other packing media. However, the high presence of C18:1ω9 in both olive oils tested did not lead to remarkable increases (p &gt; 0.05) of this FA presence. Additionally, the presence of total ω3 FAs, C20:5ω3 and C22:6ω3 did not provide differences in canned fish muscle as a result of using different packing media. In all canned samples, ω3/ω6 values were included in the 8.2-10.8 range. Prior frozen storage did not have a substantial effect (p &gt; 0.05) on the FA group (STFA, monounsaturated FA, PUFA, total ω3 FA) and FA ratio (PUFA/STFA and ω3/ω6) values.

Antioxidant Effect of Octopus Byproducts in Canned Horse Mackerel (Trachurus trachurus) Previously Subjected to Different Frozen Storage Times.

The effects on lipid damage in canned horse mackerel (Trachurus trachurus) of a prior frozen storage (-18 °C) period and the presence of an octopus (Octopus vulgaris) cooking juice (OCJ) in the packing medium were investigated. An increase of the frozen storage time favoured an increase (p &lt; 0.05) of free fatty acid (FFA), peroxide, and thiobarbituric acid reactive substance contents and a decrease (p &lt; 0.05) of the phospholipid (PL) value and polyene index. Furthermore, an increased presence of OCJ in the packing medium led to an inhibitory effect (p &lt; 0.05) on fluorescent compound formation as well as to a retention (p &lt; 0.05) of the PL and FFA compounds. Colour determination showed a substantial increase (p &lt; 0.05) of L* and b* values in canned fish with previous frozen storage time. Nevertheless, this increase was partly reduced (p &lt; 0.05) by the OCJ presence in the packing medium. It is concluded that previous holding time has led to an increased lipid oxidation development and loss of beneficial lipid constituents (i.e., PLs and polyunsaturated fatty acids). Remarkably, the presence in the packing medium of preservative compounds (i.e., antioxidants) included in waste juice obtained from octopus processing provided an effective tool for lipid preservation and quality enhancement in canned fish.

Profiling carotenoid and phenolic compounds in fresh and canned fruit of peach cultivars: Impact of genotype and canning on their concentration

Peach (Prunus persica (L.) Batsch) is widely consumed both fresh and processed. Scarce information exists regarding the fate of phytochemicals after the peach canning process. The aim of the current study was to evaluate the compositional variability and impact of processing on the bioactive compounds profile of eight non-melting peach cultivars, both in fresh and canned forms, thermally processed with either light syrup (LS) or grape juice (GJ) as the packing medium. LC–MS analysis demonstrated that the phytochemical profile is primarily genotype dependent. Prediction profile statistics revealed that cv. ‘Andross’, a predominant clingstone peach cultivar, possessed the highest desirability score among all the examined cultivars. Free zeaxanthin and lutein remained relatively unaffected by the canning process compared to free β-carotene, whereas soluble phenolic compounds, such as neochlorogenic acid, chlorogenic acid, procyanidin B1 and catechin, showed a large decrease following canning. Using GJ, an additional source of polyphenols, as packing medium led to a reduction of losses for the bioactive compounds. Overall, the experimental findings demonstrated that, besides the thermal degradation of some sensitive to heating compounds, there is a bidirectional flow of the bioactive compounds between the fruit tissue and the liquid matrix, as balanced out by diffusion processes.