Sludge Of Sewage Treatment Plant Research Articles

Optimizing the process of sewage sludge collection for bioenergy generation and biofertilizer production

The conversion of sludge from sewage treatment plants (STPs) into bioenergy is a promising approach to sustainable energy generation and effective waste management. This process occurs through anaerobic digestion in the biodigesters, resulting in biogas production. However, given that the sludge comes from various STPs in different cities, identifying the ideal locations requires careful selection due to the complexity of sludge management, associated costs, and transportation logistics. In this context, this work aims to formulate a mathematical optimization model to determine the best locations for the installation of sludge processing centers, considering the minimization of the economic, environmental, and social costs. The model is implemented in MATLAB software, and geospatial analysis of the regions of interest is performed using QGIS software. For model validation, three distinct instances are considered. The results obtained demonstrate significant potential in terms of biogas and electricity production, with the highest values for the third instance being 61,997,501 Nm³/year and 149,275 MWh/year, respectively. The proposed methodology represents a crucial step toward sustainability, as it promotes the generation and use of bioenergy from STP sludge and contributes to improved waste management and the prevention of air, soil, and water pollution.

Reuse of Sewage Sludge as Organic Agricultural Products: An Efficient Technology-Based Initiative

Rapid urbanisation has led to a dramatic increase in sewage sludge production. There are limited methods of managing sewage sludge along with high energy and monetary investment. A cost-effective, environment-friendly, and sustainable solution needs to be developed for the management of sewage sludge. In the current study, sludge from the Jagjeetpur sewage treatment plant (STP) had been collected, composted, and characterized during January and February 2022. A comparison of STP sludge compost and compost made from farmyard manure showed the presence of essential agricultural nutrients in them, due to which they find application for plant growth. Two products, Jaivik Poshak and Jaivik Prom, containing farmyard compost, were compared with the amended version of the same, containing compost from STP sludge instead of normal compost. The results showed that the modified Jaivik Poshak was the best for maintaining pH and increasing electrical conductivity. The available nitrogen in the soil upon its application increased by 1.6 times (p<0.001) with respect to control, and it brought about 100% tomato seed germination within sixteen days. The above finding has been validated by goodness of fit value, factor analysis, and hierarchical analysis. The product, modified Jaivik Prom increased organic carbon content and brought about 5.81 and 8 times the enhancement in available phosphorous (p<0.001) and potassium (p<0.001) content in soil, respectively, with respect to the control set. The heavy metal content in the soil as a result of all types of treatment was within the permissible limit. This study thus proves that sludge from STP may be used for agricultural uses after proper fortification and testing to convert waste to wealth along with environmental sustenance.

Decomposition of non-steroidal anti-inflammatory drugs by activated sludge supported by biopreparation in sequencing batch reactor

The presence of non-steroidal anti-inflammatory drugs in wastewater from sewage treatment plants indicates that they are not completely biodegradable. The designed biopreparation based on immobilized bacteria enables the degradation of paracetamol, ibuprofen, naproxen and diclofenac at a rate of 0.50 mg/L*day, 0.14 mg/L*day, 0.16 mg/L*day and 0.04 mg/L*day, respectively. Lower degradation of drugs in the mixture than in monosubstrate systems indicates their additive, antagonistic effect, limiting the degradative capacity of microorganisms. The biopreparation is stable for at least 6 weeks in bioreactor conditions. Biochemical parameters of activated sludge functioning showed increased oxygen demand, which was related to increased ammonia concentration caused by long-term exposure of activated sludge to drugs. Reduced metabolic activity was also observed. The preparation enables decomposing drugs and their metabolites, restoring the activated sludge's functionality. The tested biopreparation can support activated sludge in sewage treatment plants in degrading non-steroidal anti-inflammatory drugs and phenolic compounds.

Prevalence of diverse antimicrobial resistance genes and bacteria in sewage treatment plant-derived sludge environment.

Antimicrobial resistance (AMR) contamination in the environment is one of the most significant worldwide threats of the 21st century. Since sludge is heavily exposed to diverse contaminants, including pharmaceuticals, the inhabitant bacterial population is expected to exhibit resistance to antimicrobial agents. In this study, sewage treatment plant (STP) sludge samples were analyzed to assess the antibiotic-resistant bacterial population, abundance of AMR genes (ermF, qnrS, Sul1, blaGES, blaCTX-M, and blaNDM), and mobile genetic elements (intl1 and IS26). Out of 16, six bacterial isolates exhibited resistance to 13 antibiotics with a high multiple antibiotic resistance index (MARI) (0.93) and high metal tolerance. Quantitative polymerase chain reaction showed the abundance of target genes ranging from 6.6×103 to 6.5×108 copies g-1 sludge. The overall outcome reveals that STP sludge comprised varied multidrug-resistant bacterial populations. It will give insights into the functions of heavy metals and biofilm development in the selection and spread of AMR genes and the associated bacteria. Therefore, the application of sludge needs proper screening for AMR and metal contamination prior to its countless applications. This study will contribute immensely to the risk analysis of STP effluents on environmental health, including control of AMR transmission.

Parachitinimonas caeni gen. nov., sp. nov., a novel member of family Burkholderiaceae isolated from activated sludge collected in Shenzhen, PR China.

A Gram-stain-negative, strictly aerobic and filamentous bacterial strain, designated as DQS-5T, was isolated from the activated sludge of a municipal sewage treatment plant in Shenzhen, PR China. Optimal growth was observed at 28 °C and pH 7.5. Catalase and oxidase activities were detected. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DQS-5T was most closely related to the genera Chitinimonas and Chitinivorax (91.0-93.4 % and 92.5 % 16S rRNA gene sequence similarity, respectively) and was close to the member of the family Burkholderiaceae. The complete genome sequence of strain DQS-5T contains 5 653 844 bp and 57.3 mol% G+C. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between the genome of strain DQS-5T and those of its close relatives were 75.9-77.2, 19.0-20.3 and 57.2-61.8 %, respectively. Chemotaxonomic analysis of strain DQS-5T indicated that the sole respiratory quinone was ubiquinone-8, the predominant cellular fatty acids were C16 : 0 and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), and the major polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, aminophospholipid and aminolipid. The phylogenetic, genotypic, phenotypic and chemotaxonomic data demonstrate that strain DQS-5T represents a novel species in a novel genus within the family Burkholderiaceae, for which the name Parachitinimonas caeni gen. nov., sp. nov., is proposed. Strain DQS-5T (=KCTC 92788T=CCTCC AB 2022320T) is the type and only strain of P. caeni.

Research on the Value of Sludge Resource Utilization in A Sewage Treatment Plant in A Certain City in Southwest China

With the acceleration of urbanization and the improvement of living standards, environmental issues are receiving increasing attention. In recent years, the National Development and Reform Commission and other three departments have issued the "Implementation Plan for Harmless Treatment and Resource Utilization of Sludge", proposing to implement harmless treatment of sludge and promote resource utilization, which is an important measure to build a beautiful China. In order to prevent water pollution and improve environmental quality, the sewage treatment capacity in the Southwest region has rapidly increased, and the sludge production has also sharply increased. The sludge contains various organic pollutants and nutrients, and the resource utilization of sludge has attracted people's attention. Analyzing the properties and nutrients of sludge is a prerequisite for scientific and reasonable sludge resource utilization. Therefore, this article takes sewage treatment plant sludge as the research object, conducts in-depth research on sludge properties and nutrients, and conducts in-depth research on the resource utilization value of sludge.

The potential of electron beams for the removal of microplastics from wastewater and sewage sludge

Wastewater and sewage sludge treatment plants are known to be important entrance routes for microplastics (MPs) into the aquatic environment. Although traditional wastewater treatment plants with primary and secondary purification processes can remove over 99 % of MPs, the majority of these are believed to be deposited into the sewage sludge. This provides a route into the environment, especially if the treated sludge is used as a fertilizer on agricultural land. Although methods do exist for the removal of MPs from water, there are limited studies with sludge. The possibility of using electron beam treatment for the removal of microplastics from wastewater and sewage sludge has been investigated in the laboratory using both tap water and actual sewage sludge. Microplastics were created from six types of plastics in daily use, <1.5 mm in size, and treated with a range of doses in tap water and in sewage sludge, taken from a sewage sludge treatment plant, both before and after anaerobic digestion, with a 10MeV accelerated electron beam. In this treatment, the electrons were found to act as a coagulant by modifying the surface charge of the microplastics. This significantly increases the sedimentation of four out of six of the types of MP in both water and sludge, while the other two largely remain floating. Density separation techniques of the treated samples have then demonstrated removal efficiencies in the range 85–95 % for five of the MP types and of around 70 % for the sixth at reasonable EB doses. This potentially provides a route to high efficiency removal from sludge.

Application of Immobilized Biocatalysts in the Biotransformation of Non-Steroidal Anti-Inflammatory Drugs

Among the micropollutants identified in the environment, non-steroidal anti-inflammatory drugs (NSAIDs) dominate more and more often. This is due to both the high consumption and low efficiency of biological wastewater treatment plants, where the initial transformation of NSAIDs most often takes place. The solution to the problem may be using preparations supporting activated sludge in sewage treatment plants in the biodegradation of NSAIDs. Therefore, the research aimed to develop a biopreparation stimulating the activated sludge of the sewage treatment plant to decompose paracetamol and selected NSAIDs. This biopreparation is based on strains of Stenotrophomonas maltophilia KB2, Planococcus sp. S5, Bacillus thuringiensis B1(2015b), and Pseudomonas moorei KB4 immobilized on a plant sponge. As a result of the tests, it was shown that the optimal species composition of the proposed preparation includes all tested strains immobilized on a carrier with a mass of 1.2 g/L. The system optimization showed that the optimal amount of strains on the carrier was 17 mg/g of the carrier, 15 mg/g of the carrier, 18 mg/g of the carrier, and 20 mg/g of the carrier for KB4, B1(2015b), KB2, and S5, respectively. The presence of phenol stimulated the degradation of the tested drugs, and this effect deepened with increasing phenol concentration. At the same time, the degradation rate of the mixture of NSAIDs in the presence of phenol did not depend on the amount of biomass. The lack of inhibition in the presence of an additional co-contaminant, i.e., phenol, indicates that the preparation constructed in this way has a chance of being used in sewage treatment plant systems, where introduced strains are exposed to various aromatic compounds.

Design of Urban Sludge Emission Reduction Optimisation Strategy Based on Fuzzy Neural Network

Abstract Urban sewage sludge treatment is important for sustainable utilisation and virtuous cycle of freshwater resources. However, with the improvement of sewage discharge standards, ensuring stable operation of sewage sludge treatment plants is becoming an urgent problem to be solved in the sewage treatment industry. This paper proposes a FNN control framework based on different working conditions to optimise the whole process of municipal sewage sludge treatment and discharge. The framework first divides the working conditions according to the weather, forming a separate feature and an input vector together with the typical indicators of other sewage treatment plants. Then the FNN is used to complete the control and optimisation of various indicators, achieving the dual objectives of reducing energy consumption and optimising water quality. Finally, the model is tested for the tracking index of sewage flow. The results demonstrate that the FNN control method used has significantly lower MAE than the single method in the two indexes of energy consumption and water quality evaluation. This provides new ideas for the optimisation of urban sewage sludge treatment process in the future. Overall, the paper effectively highlights the importance of urban sewage sludge treatment and presents a well-designed FNN control framework for optimising the treatment process. Additionally, the paper could benefit from further elaboration on the significance of the results obtained, and suggestions for future research in this area.

Analogous study of cumulative biogas production by anaerobic digestion of sewage treatment plant sludge, the proposal of universal dimensionless models

AbstractThe current global concern is how to replace polluting fossil fuels with sustainable green fuels. On this basis, in this study, a characterization protocol for sewage sludge in Algeria was carried out. Their objective was to study the process of anaerobic digestion for biogas production by analogy to experiments that have already been made in the literature. The performance of the proposed models has been validated with experimental data from the scientific literature. Biodegradable organic matter levels are high (160–500 mg L−1) giving an acceptable yield for biogas production. The modeling of cumulative biogas production was carried out by Gompertz and models were proposed for different products. It has been observed that there is a better agreement of the models proposed with the experimental data with a maximum value of r2 = 0.9996. The modeling of the degradation of organic matter was carried out by the first order‐model, and dimensionless models were proposed. The latter gave a good agreement with the experimental data better than the model in the literature, with a maximum value of r2 = 0.9985. The proposed models to study the anaerobic digestion process of organic matter, as well as those related to the process of cumulative biogas production, are universal (without units of measurement), which will help producers in this field to improve production, as well as reduce the investment cost through preliminary simulations.

Determination of Rheological Parameters of Non-Newtonian Fluids on an Example of Biogas Plant Substrates

Non-Newtonian fluids are commonly used in a wide range of industries; one example are in biogas power plants. Proper measurements and modeling of such fluids can be crucial from the design and operations point of view. Results presented in this study covered seven samples from three plants (a sewage sludge treatment plant, utilization biogas station and a biogas plant in a sugar factory), including mechanically thickened excessive activated sludge (MTEAS), sugar beet pulp (SBP), liquid fruit and vegetable waste (FVW), beet roots (BR) and corn waste (CW); their mixtures were prepared as in a real plant. The total solid content remained below 6.8% for all samples. The apparent viscosity (15 RPM) did not exceed 10 Pas in any sample. A correlation analysis for solvent type influence on the viscosity was carried out. The obtained results were analyzed, and the Herschel–Bulkley rheological model was selected for the fluid description. Then, the Moullinex method was applied to determine the H–B model parameters. The obtained results may contribute to the proper design and operation of various biogas power plants, in which viscosity seems to be one of the crucial flow parameters that influences the device types used, as well as energy consumption.

Distribution and removal mechanism of microplastics in urban wastewater plants systems via different processes

Microplastic pollution threatens water systems worldwide. As one of the most important parts of city wastewater treatment, wastewater treatment plants are not only microplastics interception barriers but also emission sources. Water samples were collected from each sewage treatment plant stage and sludge from the sludge dewatering room. Microplastics were extracted using wet peroxide oxidation and flotation, and the abundance, size, shape, and polymer type of microplastics were detected. Basis on the results, the influence of each process on the removal rate and characteristics of microplastics under the same influent source was analysed. The influent microplastic concentration in this study was 32.5 ± 1.0 n/L, which rapidly decreased after treatment. The removal rates of the sequencing batch reactor activated sludge, cyclic activated sludge, and anaerobic anoxic oxic technologies were 73.0%, 75.6%, and 83.9%, respectively. Most microplastics were transported to the sludge, and the concentration of microplastics in dehydrated sludge was 27.2 ± 3.1 n/g. Microplastics removal occurred primarily during the primary and secondary stages. Disposal processes, settling time, and process design affected wastewater treatment plant microplastic removal rates at each stage. Significant differences in microplastic characteristics were observed at each stage, with the most abundant being fragment shaped, particle sizes of 30–100 μm, and black in colour. Sixteen polymer types were identified using a Raman spectrometer. The predominant polymers are polypropylene, polyethylene, and polyethylene terephthalate. This study demonstrates that optimising the process design of existing wastewater treatment plants is crucial for the prevention and control of microplastic pollution. It is suggested that the process settings of contemporary wastewater treatment plants should be studied in depth to develop a scientific foundation for avoiding and managing microplastic pollution in urban areas.

Adsorption of crystal violet dye from aqueous solution by activated sewage treatment plant sludge

Adsorption of crystal violet dye from aqueous solution by activated sewage treatment plant sludge

Planning of Sewage Sludge Treatment Plant Poso Regency

In order to process the fecal sludge that is collected from the residents of Poso Regency, a Sewage Sludge Treatment Plant has been built. For the purpose of treating sewage sludge, this facility is one method utilized to enhance wastewater quality. There is a Sewage Sludge Treatment Plant in Poso Regency, however, it is in disrepair and cannot meet current needs. In light of this, Poso Regency needs cutting-edge technology for treating sewage sludge. The goal of this research was to establish the average entry of fecal sludge and its volume for Poso Regency to create an appropriate system that meets all requirements set forth by the Ministry of Public Works.

Performance comparison of phosphorus recovery from different sludges in sewage treatment plants through pyrolysis

Recycling of phosphorus (P) from pyrolysis sewage sludge is a good methodology to deal with the deficit of P resources and safely dispose the sewage sludge. However, it is essential to determine the type of sludge in sewage treatment plants (STPs) along with the most appropriate pyrolysis temperature. These factors affect the form and bioavailability of recoverable P. Thus, four kinds of sludge in a typical STP were selected, and three pyrolysis temperatures including 300, 500, and 700 °C were set to find a suitable strategy for P recovery. The results indicated that with increasing pyrolysis temperature, more organic phosphorus (OP) was transformed into inorganic phosphorus (IP) and more non-apatite inorganic phosphorus (NAIP) was converted to apatite phosphorus (AP, mainly Ca3(PO4)2, Ca(H2PO4)2, Mg3(PO4)2, Ca3Mg3(PO4)4, and Ca5(PO4)3OH). Compared to other sludges, dewatered cake sludge (CS) pyrolyzed at 700 °C had the highest AP content, about 1.1–3.6 times that in other pyrolysis products, and the highest Ca5(PO4)3OH content containing 35.8% of total phosphorus (TP). The contents of P-2% citric acid (CA) and neutral ammonium citrate (NAC) in CS obtained by pyrolysis at 500 °C reached 45.6 and 49.6 mg/g, respectively, which were 1.1–3.0 and 1.1–2.8 times that of P-CA and P-NAC in other sludges and their biochars, respectively. Moreover, the diethylenetriaminepentaacetic acid extraction analysis indicated that the good stability of heavy metals in CS-derived biochar was better than that in the feedstock. Hence, to ensure the efficiency and safety of P, CS is used as raw material in STPs to recover P resources. CS-500 can be used as the direct P source of land owing to the highest concentration of bioavailable P (P-CA and P-NAC), while CS-700 can be used to represent a slow-release P fertilizer because it contains the highest concentration of AP.

Briquettes from sludge in sewage treatment plant: calorific power.

Due to the large volume of sewage generated every day, there is a high demand for its treatment. The by-product (called sludge) generated after the treatment process has caused problems in terms of its final disposal. Since the typical end off for this waste is landfills, it is mandatory reducing the landfill amount and the risk of soil contamination. The present work explored an adequate final disposal of the sludge as a sustainable alternative. For this purpose, briquettes were produced using dry sludge from the Sewage Treatment Plant of the Minas Gerais (Brazil) Sanitation Company and vegetable oil used to thicken the briquettes. These briquettes were compared to eucalyptus charcoal in terms of their calorific potential, through immediate analysis, since Brazil has a high demand for primary energy, especially in the industrial sphere. The calorific potential of charcoal reached 16.66MJ/kg, while that of briquette reached 12.94MJ/kg. However, briquettes had a density much higher than charcoal, so it takes a smaller volume of briquettes to achieve the same burning capacity as a large volume of charcoal.

Differential variations of intracellular and extracellular antibiotic resistance genes between treatment units in centralized sewage sludge treatment plants

Centralized sludge treatment plants (CSTPs) are implicated as strong hotspots of antibiotic resistance genes (ARGs). However, the knowledge gap on the fate of intracellular and extracellular ARGs (iARGs and eARGs), and the functionality of resistant hosts limit risk assessment and management of CSTP resistome. Here, the flow of iARGs and eARGs across treatment units and analyses of ARG hosts were systematically explored in three full-scale CSTPs using quantitative metagenomic approaches. We found that 29% of sludge ARGs could be removed, with iARGs being dominant in the produced biosolids. The treatment process significantly affected the variations of iARG and eARG abundance while no significant difference in composition between iARGs and eARGs was observed in CSTPs. 15% of 295 recovered genomes were identified as antibiotic-resistant hosts, among which Actinobacteriota tended to encode multiple resistance. The key functions of ARG hosts were relative to the biological organic removal (e.g., carbohydrates). There also existed relationships between certain resistance mechanisms and functional traits, indicating that ARGs might take part in the physiological process of microorganisms in the sludge treatment. These findings provide important insight into the differential resistome variations and host functionality, which would be crucial in the management of antibiotic resistance in CSTPs.

Analysis of aerobic and anaerobic sewage sludge disposal concepts

The article aimed to analyze the concept of modernisation of sludge management prepared for an exemplary sewage sludge treatment plant. Four variants of solutions, based on different processes, aerobic (oxygenic), anaerobic or – aerobic – anaerobic, were discussed. The article presents the characteristics of essential elements of the proposed solutions. The technical and technological parameters of each of the variants are exposed. The expected capital expenditure and basic operating costs are presented. A cost-effectiveness analysis of the options has also been carried out. The analysed technological processes ensure obtaining hygienically and sanitary safe end products. They contribute significantly to minimising the amount of sewage sludge. The most economically efficient, with the lowest average annual costs, is the variant with the application of anaerobic thermo-philic-mesophilic sludge stabilisation. The highest average annual costs were obtained for the variant with drying and incineration of sludge.

Incorporation of the Sludge of Sewage Treatment Plant on Ceramic Bricks Manufacture

Treatment processes used in most sewage treatment stations generate as by-product a material named sludge. The amount of sludge grows proportionally with the increase in effluent collection and treatment services, which in turn must accompany population growth. The disposition of waste generated in an environmentally correct and economically viable way is one of the biggest challenges faced by companies that operate sanitation services. The ceramic industry presents a great potential for the use of this waste. The goal of this work was to evaluate the effect of the incorporation of the sewage sludge in the ceramic mass for the manufacture of solid bricks. The water absorption was lower for bricks with 10% sludge, but it increased for bricks with 15% sludge, resulting in products that presented water absorption slightly beyond of the limit of the standard NBR 15270. However, the results are promising because they show that additions of 10% or 15% sludge increased the compressive strength markedly.

METHANE PRODUCTION IN THE CO-DIGESTION OF LANDFILL LEACHATE WITH DOMESTIC SEWAGE AND THE METHANOGENIC ACTIVITY OF FULL-SCALE UASB REACTORS

The study aimed to individually assess the specific methanogenic activity of the sludge of 10 UASB reactors from a full-scale domestic sewage treatment plant (STP) and the sludge behavior under conditions of anaerobic co-digestion of leachate with domestic sewage in dilutions (v/v) of 0.1%, 1.0%, 2.5%, 5.0%, 10.0%, 25.0%, 50.0%, 75.0% and 100%. In order to compare the influence of the activity on co-digestion sludge, a parallel test was performed with sludge coming from the treatment of swine wastewater under the same conditions as the test with STP sludge. Specific methanogenic activity results showed the difference between STP sludge conversion capacities at each reactor, as well as preponderant conversion routes, which can have several origins within the mesh of factors that affect the units. Co-digestion analyses pointed out a better adaptation of piggery sludge to higher organic loads, such as the viability of up to 50% of leachate in relation to treated sewage volume, while the STP sludge showed a more delayed response in methane production. The best co-digestion condition was 10% leachate. The study highlights the possibility of increased leachate fractions in the co-digestion with domestic sewage with methane production potential, with incorporation of sludge from agro-industrial wastewater treatment.