Tank Sludge Research Articles

Sea cucumber, Neostichopus grammatus, density and tank cleaning frequency affect abalone, Haliotis midae, growth in integrated multitrophic aquaculture

AbstractThe integrated multitrophic aquaculture (IMTA) of sea cucumber and abalone has been proposed as a potential bioremediation tool that stimulates increased abalone growth. This study assessed the role of sea cucumber stocking density and frequency of tank cleaning in IMTA on growth, water, and sludge bioremediation. The study was conducted for 16 weeks and was made of four treatments and four replicates; abalone cocultured with sea cucumber (low density—27: 1 g [abalone (ab): sea cucumber (sc)]) with tanks cleaned once a week (L1); abalone cocultured with sea cucumber (low density) with tanks cleaned twice a week (L2); abalone cocultured with sea cucumber (high density—15:1 g [ab:sc]) with tanks cleaned once a week (H1) and abalone cocultured with sea cucumber (high density) with tanks cleaned twice a week (H2). Rearing water nitrite was significantly lower (p = 0.001) at high stocking density of sea cucumbers, but sludge was unaffected. Tanks cleaned once weekly had higher sludge organic matter (p = 0.015) and sludge sulfur content (p = 0.020) and lower sludge carbon (p = 0.003) and nitrogen content (p = 0.049). At the end of the experiment, the stocking density of sea cucumber and frequency of tank cleaning affected abalone mean weight [p = 0.047; p = 0.011, respectively] without a significant interaction (p = 0.517). Abalone in H1 had a higher mean weight and shell length than abalone in L2 and H2 but was similar to those in L1. The stocking density and frequency of cleaning used in this study had no effect on the growth of sea cucumbers [p = 0.150; p = 0.470, respectively]. This study has shown that in an abalone–sea cucumber IMTA system, the stocking density of sea cucumber and the frequency at which tanks are cleaned influence abalone growth and bioremediation of the rearing water. Our result suggests H1 as the best density (ab:sc) and cleaning frequency. The tank cleaning frequency alone affects the tank sludge quality; tanks need not be washed too frequently as, in addition to causing animal stress, cleaning markedly increased carbon and nitrogen level of tank sludge. Both these effects are likely to negatively impact abalone growth.

Effects of Polyethylene Terephthalate Microplastics on Anaerobic Mono-Digestion and Co-Digestion of Fecal Sludge from Septic Tank.

Anaerobic digestion (AD) is one of the most significant processes for treating fecal sludge. However, a substantial amount of microplastics (MPs) have been identified in septic tanks, and it remains unclear whether they impact the resource treatment of feces. To investigate this, polyethylene terephthalate (PET) was used as an indicator of MPs to study their effect on the anaerobic digestion of fecal sludge (FS). Two digestion systems were developed: FS mono-digestion and FS co-digestion with anaerobic granular sludge. The results indicated that the effects of PET varied between the two systems. PET inhibited volatile fatty acid synthesis in both systems, but the inhibition period differed. During mono-digestion, PET slightly increased gas and methane production, in contrast to the co-digestion system, where PET reduced methane production by 75.18%. Furthermore, in the mono-digestion system, PET increased soluble chemical oxygen demand and ammonia nitrogen concentrations while blocking phosphorus release, whereas the co-digestion system showed the opposite effects. Ultimately, the choice of digestion method is crucial for the resource utilization of septic tank sludge, and the impact of MPs on AD cannot be ignored.

Analysis of the Influence of Machine Operation Parameters on the Technical Characteristics of the Elevator in the Point of Cleaning and Washing of the Equipment Park

Purpose. The study is aimed at determining the nature of the influence of the operating parameters of the enterprise's machines (the number of tracked and wheeled machines, the annual consumption rates of their motor resources) on the technical characteristics of the elevator for cleaning the dirt settler of the vehicle cleaning and washing equipment park, in particular, the height of the elevator and its productivity, as well as building analytical and graphical dependencies of these values on the operating parameters of the machinery. Methodology. To achieve this goal, we used the calculation algorithms presented in the modern technical literature and analyzed the factors and values that affect the height and capacity of the elevator of the station. It has been established that in order to determine the design parameters of the elevator, it is necessary to have statistical data on the operation of machinery at the enterprise and to carry out a detailed calculation, which includes: the mathematical expectation of the average daily number of machine trips from the fleet for different types of machinery, as well as the total value, the number of numbered machine servicing, the number of external machine washing stations, and the geometric parameters of the dirt tank. Findings. A graphical analysis of the influence of the number of tracked and wheeled vehicles and their annual consumption rates of motor resources on the value of its height and productivity was carried out for the elevator of the cleaning and washing station of the fleet of a particular enterprise, which is intended for cleaning the sludge tank. It was found that the functions of change in productivity and height are linearly increasing (with other parameters fixed). Originality. The authors first investigated the dependencies of the design parameters (height and capacity) of the elevator, built analytical dependencies of the mathematical expectation of the average daily number of machine trips for wheeled and tracked vehicles on the number of relevant machines and annual motor resource consumption rates, as well as the height and capacity of the elevator. For the examples of enterprise fleets with equipment operation parameters taken from statistical data, a graphical analysis of the constructed dependencies was carried out. Practical value. The use of the constructed dependencies makes it possible to determine the general nature and range of changes in the above design parameters in the case of varying equipment performance at a particular enterprise. The proposed dependencies can be used to quickly determine the required design parameters of an elevator based on specific data on the operation of equipment.

Simultaneous nitrogen and phosphorus removal by immobilized bacterial particles of denitrifying phosphorus accumulating microorganisms and its application

Enterobacter cloacae G, a novel denitrifying phosphorus-accumulating bacterial strain, was isolated from anaerobic sludge tank of a wastewater treatment plant used for pig farms. It was discovered that a pH of 7, a temperature of 30°C, an initial phosphorus concentration of 8 mg/L, and a C/N ratio of 10 were the strain's ideal growth conditions. To ensure the stability of strain G in wastewater treatment, strain G was immobilized by 5 % polyvinyl alcohol, 2 % sodium alginate, and 0.6 g of biochar and crosslinked for 9 h in 4 % calcium chloride saturated boric acid solution via an orthogonal test. After the immobilized microspheres were introduced into the sequencing batch reactor (SBR), the nitrate and phosphate removal rates achieved were 89.36 % and 65.53 %, respectively, with a hydraulic retention time (HRT) of 8 hours, a pH of 7.5, and a C/N ratio of 4.5. The immobilized microspheres containing strain G demonstrated potential for the treatment of nitrogen-rich and phosphorus-rich wastewater.

Lab-based scale measurements of internal storage of crude oil tank based on non-contact infrared thermography technique

Non-contact sludge measurement methods for storage tanks can address the challenge of measuring the volume of sedimented sludge during long-term storage. While infrared thermography technology can address the issue of liquid level detection, its measurement accuracy for the undulating interface of sludge is insufficient. This study designed and constructed experimental setups for measuring sludge in storage tanks. In this study, infrared images taken by an infrared camera were used to record the temperature distribution of the outer wall of the storage tank. The threshold segmentation method is used to determine the accurate sludge boundary line in image processing. Finally, the Three-Dimensional Tank Residue Recovery Algorithm (3D-TRRA) was applied to fit the 3D distribution of the sludge and calculate accurate sludge volumes. The results indicate that the best segmentation is achieved with a threshold of 170. The measurement error for sludge volume is less than 5%. Accurate visual positioning and recognition of sludge are achieved.

Knowledge, attitude and practice on water, sanitation and hygiene (WASH) and COVID-19 among households in rural Bangladesh

Enhanced water, sanitation, and hygiene (WASH) conditions can significantly reduce the incidence of communicable diseases and deaths related to diarrhea by up to 65%. The US Centers for Disease Control and Prevention (CDC) advocates regular handwashing with soap and water for at least 20 seconds as an effective measure to mitigate the spread of COVID-19. This study aims to assess rural Bangladeshi households' perceptions and knowledge concerning the COVID-19 pandemic, as well as their understanding, attitudes, and practices regarding water, sanitation, and hygiene. A cross-sectional study was conducted between June 2020 and December 2020 to evaluate knowledge and practices related to safe water, sanitation, personal hygiene, and COVID-19 in rural Bangladesh. Self-administered questionnaires, pre-tested for reliability, were utilized to collect self-reported data, which were subsequently analyzed descriptively. Of the study participants, 66.78% were female, with a mean age of 40. The majority (92.36%) demonstrated adequate knowledge of personal hygiene, although 66.78% had not received hygiene education, and a significant proportion reported low levels of hygiene practices (17.28%). Nearly all respondents (98%) reported having access to a pit latrine, either with or without a seal, yet 63.12% indicated that their toilets become unusable during floods, and 29% admitted to practicing open defecation. While nearly all respondents were aware of the ongoing COVID-19 outbreak, only 46% had a comprehensive understanding of its transmission dynamics. Moreover, knowledge about preventive measures against the pandemic was found to be limited. Despite understanding the importance of handwashing, reported hand hygiene practices were inadequate among rural households. Additionally, a majority reported inadequate management of child feces, household waste, and sludge tanks. While awareness of the COVID-19 pandemic was high, a substantial proportion of respondents lacked understanding of its transmission and prevention methods. Moreover, fewer respondents reported using hand sanitizer when venturing outside for work. Future research should explore the impact of these behaviors on health outcomes and propose targeted interventions to improve hygiene practices. Jahangirnagar University J. Biol. Sci. 12(1 & 2): 11-21, 2023 (June & December)

Corallococcus caeni sp. nov., a novel myxobacterium isolated from activated sludge.

Two myxobacterial strains (KH5-1T and NO1) were isolated from the activated sludge tanks treating municipal sewage wastewater in Japan. These strains were recognised as myxobacteria based on their phenotypic characteristics of swarming colonies and fruiting bodies. Phylogenetic analyses using the 16S rRNA gene revealed that strains KH5-1T and NO1 were affiliated with the genus Corallococcus, with the closest neighbours being Corallococcus exercitusAB043AT (99.77% and 99.84%, respectively). Genome comparisons using orthologous average nucleotide identity (orthoANI) and digital DNA-DNA hybridisation similarity (dDDH) with strains KH5-1T and NO1 and their phylogenetically close relatives inCorallococcusspp. were below the thresholds. The major cellular fatty acids of strains KH5-1T and NO1 were iso-C15:0 (31.9%, 30.0%), summed feature 3(comprising C16:1ω7c and/or C16:1ω6c) (20.2%, 17.7%), and iso-C17:0 (12.1%, 14.8%), and the major respiratory quinone was found to be menaquinone (MK)-8. Based on the phenotypic, chemotaxonomic, and phylogenetic evidence, strains KH5-1T and NO1 represent a new species in the genusCorallococcus,for which the proposed nameisCorallococcus caenisp. nov. The type strain is KH5-1T (= NCIMB 15510T = JCM 36609T).

Rapid formation mechanism of SAD granular sludge: From flocculated activated sludge to granular sludge

The SAD (Simultaneous Anammox and Denitrification) process combines anammox with denitrification to achieve nitrogen removal and carbon reduction. In this study, the flocculent activated sludge in the secondary sedimentation tank of the traditional sewage treatment plant was used as the research object. Under the action of high NH4+, adding reflux, and adjusting HRT in the UASB reactor, the transformation from flocculent sludge to SAD granular sludge was quickly realized. The results showed that a relatively stable SAD granular sludge system could be formed after 250 days of operation, and the system with reflux was more resistant to changes in the external environment than the system without reflux. In the SAD system, TN Removal Rate (TNRE) ≈ 90 %, Carbon Removal Rate (CRR) ≈ 90 %. After 3D-EEM, FTIR, and analysis of protein secondary structure, it was found that the particle stability and aggregation of the SAD stage were significantly improved compared with the previous two stages. The bacterial community structure had obvious vertical heterogeneity, mainly AnAOB (Ca. Kuenenia≈30 %) and denitrifying bacteria (Comamonas≈20 %). When the temperature drops sharply, the performance of SAD can be effectively restored by adding reflux and reducing the carbon source.

Phages in sludge from the A/O wastewater treatment process play an important role in the transmission of ARGs

Phages can influence the horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs) through transduction, but their profiles and effects on the transmission of ARGs are unclear, especially in complex swine sludge. In this study, we investigated the characterization of phage and ARG profiles in sludge generated from anoxic/oxic (A/O) wastewater treatment processes on swine farms using metagenomes and viromes. The results demonstrated that 205–221 subtypes of ARGs could be identified in swine sludge, among which sul1, tet(M), and floR were the dominant ARGs, indicating that sludge is an important reservoir of ARGs, especially in sludge (S) tanks. The greater abundance of mobile genetic elements (MGEs) in the S tank could significantly contribute to the greater abundance of ARGs there compared to the anoxic (A) and oxic (O) tanks (P < 0.05). However, when we compared the abundances of ARGs and MGEs in the A and O tanks, we observed opposite significant differences (P < 0.05), suggesting that MGEs are not the only factor influencing the abundance of ARGs. The high proportion of lysogenic phages in sludge from the S tank can also have a major impact on the ARG profile. Siphoviridae, Myoviridae, and Podoviridae were the dominant phage families in sludge, and a network diagram of bacteria-ARG-phages revealed that dominant phages and bacteria acted simultaneously as potential hosts for ARGs, which may have led to phage-mediated HGT of ARGs. Therefore, the risk of phage-mediated HGT of ARGs cannot be overlooked.

Converting Iraqi Hazardous Crude Oily Sludge into Value-Added Activated Carbon using KOH Activation Technique

Annually, a high amount of hazardous oily sludge (OS) is produced by North Refineries Company (NRC) Baiji. This work aims to study the specifications of oily sludge in crude oil storage tanks and to convert it into activated carbon (AC) by pyrolysis using KOH activated agent. The physical properties of OS have been measured and analyzed. The AC is produced by carbonizing oily sludge to char under N2 flow using KOH at an impregnation ratio of 2:1 KOH/char. The pore structure, morphology of the surface, and surface chemistry of the AC produced were characterized using Brunauer-Emmet-Teller (BET), Fourier Electron Scanning Electron Microscopy (FESEM), and Fourier-Transform Infrared Spectroscopy (FTIR). The result shows the surface area of the produced AC was 350 m2/g with a mesoporous structure. Based on the findings, the obtained surface area of the AC indicates the oily sludge was a light precursor, which is helpful in producing gas and liquid fuels rather than solid fuel.

Accounting for the microbial assembly of each process in wastewater treatment plants (WWTPs): study of four WWTPs receiving similar influent streams.

We evaluated a unique model in which four full-scale wastewater treatment plants (WWTPs) with the same treatment schematic and fed with similar influent wastewater were tracked over an 8-month period to determine whether the community assembly would differ in the activated sludge (AS) and sand filtration (SF) stages. For each WWTP, AS and SF achieved an average of 1-log10 (90%) and <0.02-log10 (5%) reduction of total cells, respectively. Despite the removal of cells, both AS and SF had a higher alpha and beta diversity compared to the influent microbial community. Using the Sloan neutral model, it was observed that AS and SF were individually dominated by different assembly processes. Specifically, microorganisms from influent to AS were predominantly determined by the selective niche process for all WWTPs, while the microbial community in the SF was relatively favored by a stochastic, random migration process, except two WWTPs. AS also contributed more to the final effluent microbial community compared with the SF. Given that each WWTP operates the AS independently and that there is a niche selection process driven mainly by the chemical oxygen demand concentration, operational taxonomic units unique to each of the WWTPs were also identified. The findings from this study indicate that each WWTP has its distinct microbial signature and could be used for source-tracking purposes.IMPORTANCEThis study provided a novel concept that microorganisms follow a niche assembly in the activated sludge (AS) tank and that the AS contributed more than the sand filtration process toward the final microbial signature that is unique to each treatment plant. This observation highlights the importance of understanding the microbial community selected by the AS stage, which could contribute toward source-tracking the effluent from different wastewater treatment plants.

Carbon footprint assessment of water and wastewater treatment works in Scottish islands

Quantifying the global warming potential of existing water infrastructure is an important step in realising the water industry's commitment to net-zero carbon. Whilst there has been an improved understanding of the global warming potential of centralized urban water infrastructure, rigorous analyses of smaller-scale rural systems are rare. This work adopts a life cycle assessment to ascertain the global warming potential of existing drinking water treatment works and wastewater treatment works associated with five Scottish islands: Arran, Iona, Jura, Barra, and Vatersay. The water systems, from source to sink, along with the use of chemicals, transportation, energy, and the reuse of waste products from water infrastructure are considered. The global warming potentials of the island's drinking water treatment works ranged from 0.18 to 0.79 kgCO2-eq/m3 of drinking water, while that for wastewater treatment works were 0.51 to 1.14 kgCO2-eq/m3 of wastewater. The global warming potential for water services on the islands can be as much as 7-times of that water services across Scotland as previously reported. Major global warming potential contributor in drinking water treatment works was the electricity consumed by the membrane bioreactors. The modelled direct emission of methane from sludge in septic tanks and for land reclamation made the largest contribution to global warming potential. It was also highly sensitive to model parameters, which highlights the need for a comprehensive exploration of process emissions from septic tanks and sludge handling. This analysis of existing rural water infrastructure is a baseline against which potential alternative low-carbon technology configurations can be compared.

Excreta flow mapping along the sanitation service chain, a case of Kombolcha town, Ethiopia

Poor management of fecal sludge (FSM) presents significant risks to public health and the environment. This study employed qualitative and quantitative data collection methods, along with the Shit Flow Diagram (SFD) data analyzing tool to investigate FSM patterns in Kombolcha town, Ethiopia. The findings indicate that 75.7% of housing unites in the town are shared toilets, with multiple households sharing a single facility. The primary toilet technologies used include cistern flush toilets (2.1%), pour/manual flush toilets (19.8%), ventilated improved pit latrines (11.1%), pit latrines with slabs (56.4%), and pit latrines without slabs (10.6%). However, 98.5% of these toilet types had either unlined or only partially lined containments. Furthermore, only 37% of households practice safe pit or sludge tank emptying. As a result, only 17% of fecal sludge goes through the sanitation value chain and is effectively treated, while 39% remains onsite and unemptied, and the remaining 44% is disposed of in a manner that poses risks to the environment and public health. The study highlights the significant public health and environmental risks associated with the high reliance on shared toilets, the prevalence of inadequately lined toilet types, and the low adoption of proper fecal sludge management practices. Addressing these challenges requires the implementation of sanitation bylaws and building code regulations that prioritize hygienic standards and promote improved toilet technologies.

Perencanaan Instalasi Pengolahan Air Limbah Rumah Sakit dr. Achmad Diponegoro Putussibau Kabupaten Kapuas Hulu

Liquid waste from hospitals is one of the by-products of various activities. This liquid waste contains many hazardous pollutants that pose a danger to hospital occupants, workers, visitors, and the surrounding community. The objectives of the planning for the wastewater treatment plant at RSUD dr. Achmad Diponegoro include designing the IPAL tank, determining the treatment method, calculating the required area in the planning process, and estimating the budget. The results of the design of the wastewater treatment facility at RSUD dr. Achmad Diponegoro use a total water demand of 78 m3/day as the basis for calculations. The wastewater treatment planning at RSUD dr. Achmad Diponegoro Putussibau uses the activated sludge treatment method, supplemented with other tanks to ensure a continuous process. The designed structure consists of seven tank, including a bar screen with an area of 0,200 m2, a collection tank with an area of 0,85 m2, an equalization tank with an area of 2,62 m2, an activated sludge tank with an area of 8,2 m2, a sedimentation tank with an area of 1,60 m2, a disinfection tank with an area of 2,13 m3, and a sludge drying bed with an area of 3 m2. The land area required for the construction of the wastewater treatment plant at RSUD dr. Achmad Diponegoro is 18,6 m2. The total estimated budget for the entire project is approximately IDR 906,500,000.00.

Targeted multi-analyte UHPLC-MS/MS methodology for emerging contaminants in septic tank wastewater, sludge and receiving surface water.

Septic tanks treat wastewater of individual houses and small communities (up to 2000 people in Scotland) in rural and semi-urban areas and are understudied sources of surface water contamination. A multi-analyte methodology with solid phase extraction (SPE), ultra-sonic extraction, and direct injection sample preparation methods was developed to analyse a comprehensive range of emerging contaminants (ECs) including prescription and over-the-counter pharmaceuticals and related metabolites, natural and synthetic hormones, and other human wastewater marker compounds in septic tank influent and effluent, river water, suspended solids, and septic tank sludge by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The number of quantifiable compounds in each matrix varied from 68 in septic tank wastewater to 59 in sludge illustrating its applicability across a range of matrices. Method quantification limits were 2.9 × 10-5-1.2 μg L-1 in septic tank influent, effluent and river water, with ≤0.01 μg L-1 achieved for 60% of ECs in all three water matrices, and 0.080-49 μg kg-1 in sludge. The developed method was applied to a septic tank (292 population equivalents) and the receiving river in the North-East of Scotland. Across all samples analysed, 43 of 68 ECs were detected in at least one matrix, demonstrating the method's sensitivity. The effluent concentrations suggest limited removal of ECs in septic tanks and a potential impact to river water quality for some ECs. However, further monitoring is required to better appreciate this. The developed methodology for a wide variety of ECs in a range of liquid and solid phases will allow, for the first time, a comprehensive assessment of ECs fate and removal in septic tanks, and their impact to surface water quality.

Experimental study on solidification/stabilization of leachate sludge by sulfoaluminate cement and MSWI by-products.

Leachate sludge is generated from the biochemical treatment sludge tank for disposing the leachate from landfill municipal solid waste (MSW). It has the characteristics of high water content and high organic matter content. Sulfoaluminate cement (SAC) is used as the main curing agent, and municipal solid waste incineration (MSWI) by-products are used as auxiliary curing agents to solidify/stabilize the leachate sludge. The influences of SAC content and MSWI by-products content on the strength and solidification mechanism of the leachate sludge are investigated by unconfined compressive strength (UCS) test and micro-observation tests. Moreover, the leaching concentration of heavy metals of the solidified samples is analyzed by leaching toxicity test. The results show that the UCS of the solidified samples increases with an increase in cement content. When the cement content is larger than 20%, the UCS of the solidified samples satisfies the strength requirement of landfill. The enhancing effect of bottom ash on the cement-solidified samples is slight. The fly ash is a good auxiliary curing agent for improving the UCS of cement-solidified samples, and the optimal dosage of fly ash is 5% and 15% for the solidified samples with 10 ~ 30% and 40 ~ 50% cement content, respectively. Ten percent fly ash can replace 10% cement to achieve better solidification effect for the solidified samples. The leaching concentration of heavy metals in the solidified sample with 30%/40% cement and 15% fly ash/bottom ash can satisfy the strength and leaching toxicity requirements of landfill. The immobilization of heavy metal of the cement and MSWI by-products solidified samples is mainly achieved through physical adsorption, physical encapsulation, ion exchange, and chemical precipitation.

A linear reduced-order model for the activated sludge process for the integration into a mixed-integer linear energy system optimisation model

Conventional wastewater treatment plants consume significant amounts of electricity. The constant aeration of the wastewater in order to foster the growth of microorganisms or the pumping of wastewater are two examples for energy-intensive processes within a plant. Case studies have shown that switching off blowers and inlet pumps for a certain period of time is possible without a loss in water quality. This yields a potential for wastewater treatment plants to provide demand response (DR) to the power system and thereby increase overall system flexibility. So far, the DR potential has only been quantified for individual plants, while the effects of large-scale DR provision by the wastewater treatment sector for the power system have not yet been studied. One reason for this is the lack of optimisation models which include both the wastewater treatment process and the power system operation in sufficient detail. Our model tackles this gap in the literature by providing a reduced-order linear biochemical model for the activated sludge process within a WWTP that can be incorporated into an operational energy system model. The results show that the effluent concentrations are predicted well by the linear reduced-order model in comparison to the results of the Standard Activated-Sludge model No. 1 (ASM1). Potential model applications are the variation of the airflow rate within a certain range and the variation of liquid influent flow rate to the system, which is a result of electricity load shedding of the inlet pumps and the blowers connected to the activated sludge tank.

Wastewater Treatment using The Photosynthetic Bacteria at Parksarp Village, Xaythany District, Vientiane Capital

Untreated waste water from the piggery farm will damage the environment and society, if, it is discharged to environment, in particular, direct impact on surrounding communities. The propose of the research is to investigate the characteristics and efficiency of the photosynthetic bacteria in employing on wastewater treatment systems. The experiment is designed and simulated the stabilization tank system that includes: an aerobic tank, sedimentation (excess sludge) tank, clear water tank and all tanks are used the same size of 50 liters, wastewater from a piggery farm was introduced into the treatment tank with a dry matter ratio 5% of the total water mass. Therefore, BOD5, COD, TSS, TKN, and pH were made prior to entering the treatment tank, photosynthetic bacteria is added 200 ml per week, detention time 7 days and after 25 days of treatment. The experiment found that, BOD5, COD, TSS, TKN concentrations reduce continuously from 366 mg/l - 192 mg/l (47.54%), 90,000 mg/l - 4,000 mg/l (95.56 %), 30 mg/l - 7 mg/l (76.67%) and 3.92 mg/l - 0.08 mg/l (97.96%), respectively.

Jeotgalibaca caeni sp. nov., isolated from biochemical tank sludge.

A Gram-stain-positive, coccoid-shaped, non-spore-forming, facultatively anaerobic bacterium, designated YN-L-12T, was isolated from the activate sludge of a pesticide plant. Colonies on tryptone soya agar were small, white, opaque and circular. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain YN-L-12T belonged to the genus of Jeotgalibaca, and showed the highest similarity to Jeotgalibaca arthritidis 1805-02T (97.0 %), followed by Jeotgalibaca ciconiae H21T32T (96.5 %), Jeotgalibaca porci 1804-02T (95.6 %) and Jeotgalibaca dankookensis EX-07T (95.4 %). The strain grew at 15-37 °C (optimum, 30 °C), with 0-6.5 % (w/v) NaCl (optimum, 0.5 %) and at pH 7-9 (optimum, pH 7.5). The major fatty acids were C18 : 1 ω9c, C16 : 1 ω9c and C16 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, glycolipid and an unidentified lipid. The DNA G+C content of the strain was 41.1 mol%. Average nucleotide identity values between strain YN-L-12T and J. arthritidis 1805-02T and J. ciconiae H21T32T were 72.8 and 72.3 %, respectively. The digital DNA-DNA hybridization values between YN-L-12T and J. arthritidis 1805-02T and J. ciconiae H21T32T were 24.1 and 20.3 %, respectively. According to the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain YN-L-12T represents a novel species of the genus Jeotgalibaca, for which the name Jeotgalibaca caeni sp. nov. is proposed, with strain YN-L-12T (=KCTC 43533T=CCTCC AB 2022400T) as the type strain.

Improved methane production from ultrasonically-pretreated secondary sedimentation tank sludge and new model proposal: Time series (ARIMA)

Secondary sedimentation tank sludge (SSTS) is a severe type of waste that needs to be treated to prevent human health risks. Anaerobic digestion (AD) alone can be ineffective for treating SSTS due to low substrate biodegradability. This study proposes the use of ultrasonic pretreatment (UP) on SSTS for 0 – 60 min. UP effect on SSTS was analyzed through the actual specific energy input, nominal energy input, and soluble chemical oxygen demand. The highest cumulative methane yield (CMY) of 241.56 mL/g VS obtained during the AD of the pretreated substrate (i.e., 30 min) was 58.4% higher than that of untreated SSTS. The resulting CMY curves were subsequently simulated via the modified Logistic and Gompertz, Artificial Neural Network, Auto-Regressive Integrated Moving-Average (ARIMA) models. As a novel proposal for predicting CMYs, the ARIMA model is recommended due to its simplicity and better performance than sigmoidal models (R2 = 0.9975 – 0.9988).