Composition Of Sludge Research Articles

Controlled release of phosphorus using lanthanum-modified hydrochar synthesized from water treatment sludge: Adsorption behavior and immobilization mechanism

For the proper disposal of water treatment sludge, novel Lanthanum (La)-modified water treatment sludge composites were synthesized using simple one-step hydrothermal carbonization. The composite La-modified hydrochar (WTSLa170–3) prepared at 170 °C for 3 h exhibited a phosphate adsorption capacity of up to 72.69 mg/g. The pore volume, pore size and specific surface area of the prepared material significantly increased, and La loaded successfully, which improved the phosphate adsorption performance compared with that of raw sludge. The adsorption kinetics and isotherms fitiing results revealed that the adsorption process was in agreement with the Freundlich model and pseudo-second-order kinetic model, and was multimolecular layer chemisorption and insensitive to the coexisting anions. The thermodynamic parameters revealed that the adsorption process had an endothermic and spontaneous nature. The adsorption mechanism was through electrostatic attraction and ligand exchange to form an inner-sphere complex, which was explored by using zero point charge analysis, Fourier infrared spectroscopy (FTIR), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). Adding La-modified hydrochar into sediment effectively inhibited the release of internal P in the sediment. The addition of this hydrochar promoted the transformation of active NH4Cl-P, Org-P and BD-P into the very stable HCl-P in the sediment, which also reduced the biologically available P content significantly. These results indicate that WTSLa170–3 can effectively adsorb and remove P in water and immobilize P in sediment, and provide a new way for the resource utilization of water treatment sludge.

Microplastics affect nitrogen cycling and antibiotic resistance genes transfer of sediment

Microplastics are prevalent in freshwater, coastal, and deep ocean sediments. However, the effects of microplastics on sedimentary microbial ecosystems have not been well reported. Using 16S rRNA gene and metagenomic sequencing, we investigated coastal sedimentary sludge microbial community structure, composition, function, assembly, and propagation of antibiotic resistance genes (ARGs) in response to different microplastics. The nitrifier, denitrifiers and ammonia oxidizer were significantly altered upon microplastics exposure. The concentrations of NO3−, NO2−, and NH4+ in PE and PET treated groups were in consistent with relative abundances of corresponding functional genera. The increased antibiotic efflux ARGs abundance in PE, PET, and PVC groups was directly related to the promoted efflux pump system. Reactive oxygen species (ROS) production, ROS-mediated DNA damage, and increased stress response induced by microplastics exposure might be the reason for the promotion of ARGs transfer. Assembly of dominate nitrogen degrading genus and ARGs hosts tended to be deterministic under the pressure of microplastics, indicating the selective effect of microplastics.

Characterizing sludge pyrolysis by machine learning: Towards sustainable bioenergy production from wastes

Sludge pyrolysis has sparked the interest of researchers because of its capability to dispose of hazardous residues while producing valuable bioproducts. Numerous expensive and laborious experiments are conducted to understand sludge pyrolysis. Machine learning technology can eliminate the need for experimental measurements by systematically learning relationships between variables from historical data. This research aimed to propose a machine learning model to characterize sludge pyrolysis products. A comprehensive database covering various sludge types and pyrolysis reaction conditions was constructed from experimental data. The k-nearest neighbor algorithm was used to reconstruct the missing inputs of sludge composition. The principal component analysis method was then used to decrease dataset dimensionality and acquire relevant information. The obtained scores were normalized and introduced into three machine learning models. The input variables were the chemical properties of sludge and reaction conditions. The response parameters were the distribution and composition of pyrolysis products. Based on descriptive data analysis, the optimum bio-oil yield was obtained at temperatures between 500 and 600 °C. At higher temperatures (700–800 °C), a transition was observed in the product distribution towards more syngas. The random forest regression model showed the highest accuracy among the applied models, with a correlation coefficient higher than 0.813 and a relative mean squared error lower than 12.51. The SHAP analysis using the random forest algorithm was successfully conducted to understand the importance of input variables on output responses. The five top significant features affecting bio-oil yield were ash content, fixed carbon content, operating temperature, and volatile matter content.

Formation of vivianite in digested sludge and its controlling factors in municipal wastewater treatment

Engineering solutions to recover phosphorus from municipal wastewater are required to close the anthropogenic phosphorus cycle. After chemical phosphorus elimination by iron, the ferrous iron‑phosphorus mineral vivianite forms in digested sludge, and its separation is being researched at the pilot scale. In this study, sludge samples from 16 wastewater treatment plants (WWTPs) demonstrated that phosphorus bound to biomass and redox-sensitive iron in activated sludge was transformed into other phosphorus binding forms, including vivianite, during digestion. Vivianite quantity was approximated using X-ray diffraction and two sequential extractions. These three independent methods of approximating vivianite quantity were closely related confirming their relationship to the vivianite content in the samples. The digested sludge from three WWTPs exhibited comparatively high levels of vivianite-bound phosphorus approximated between 31 % and 51 % of total phosphorus. The controlling factors of vivianite formation were investigated in order to enhance its formation in digested sludge and increase the amount of phosphorus recoverable as vivianite. They were identified using single and multivariate correlation (MLR), considering the sludge properties, sludge composition, and process parameters within the operating range of the 16 WWTPs. Increasing iron content was verified as the primary predictor of significantly increased vivianite formation (MLR: p < 0.001). In addition, increasing sulphur content was found to be an additional significant factor that decreased vivianite formation (MLR: p < 0.05). Furthermore, a comparison of plants using sulphur-free (FeCl2 and FeCl3) and sulphur-containing (FeSO4 and FeClSO4) precipitants indicated that the latter could increase the sulphur content in digested sludge (one-tailed Welch two-sample t-test: t(14.6) = 2.3, p = 0.02). Thus, by increasing the sulphur content, the use of sulphur-comprising precipitants may counteract vivianite formation, whereas sulphur-free precipitants may facilitate it and, hence, promote vivianite recovery.

Fractional factorial experimental design for optimizing volatile fatty acids from anaerobic fermentation of municipal sludge: Microbial community and activity investigation

Volatile fatty acids (VFAs) production from municipal sludge is a promising venture for resource recovery while ensuring wastewater treatment plants' ecological and economic sustainability. This study used a fractional factorial design (FFD) and response surface methodology (RSM) to optimize VFAs production from municipal sludge in semi-continuous flow acid fermenters (AFs) based on four critical parameters (i.e., sludge retention time (SRT), sludge composition, pH, and temperature) interactively and individually. To ascribe the mechanisms to VFAs production dynamics, non-methanogenic microbial activity assays and microbial community composition linked to the VFAs yields were explored. FFD and RSM successfully optimized VFAs production in the AFs, and a second-order polynomial model with an R-squared of 0.83 was derived. Optimal model conditions for VFAs production were 3-days SRT, 45 °C, pH 8.1, and 0.92 sludge composition (VS/TS ratio). Under these conditions, the model predicted a 3.47-fold increase in VFAs production, close to the experimental value of 3.48. AFs at pH of 8.1 and varying temperatures harbored the highest proportion of fermentative bacteria, mainly Clostridia, and lowest community diversity, indicating strong selective pressure for VFAs-producing populations. Furthermore, the microbial activities assays provided quantitative functional information linked to the microbial communities in each AF configuration consistent with VFAs production.

Variation of the element composition of municipal sewage sludges in the context of new regulations on phosphorus recovery in Germany

Phosphorus (P) recovery is obligatory for all sewage sludges with more than 20 g P/kg dry matter (DM) from 2029 in Germany. Nine wastewater treatment plants (WWTPs) were chosen to investigate variations of phosphorus contents and other parameters in sewage sludge over the year. Monthly sewage sludge samples from each WWTP were analyzed for phosphorus and other matrix elements (C, N, H, Ca, Fe, Al, etc.), for several trace elements (As, Cr, Mo, Ni, Pb, Sn) and loss of ignition. Among the nine WWTPs, there are four which have phosphorus contents both above and below the recovery limit of 20 g/kg DM along the year. Considering the average phosphorus content over the year, only one of them is below the limit. Compared to other matrix elements and parameters, phosphorus fluctuations are low with an average of 7% over all nine WWTPs. In total, only hydrogen and carbon are more constant in the sludge. In several WWTPs with chemical phosphorus elimination, phosphorus fluctuations showed similar courses like iron and/or aluminum. WWTPs with chamber filter presses rather showed dilution effects of calcium dosage. As result of this study, monthly phosphorus measurement is highly recommended to determine whether a WWTP is below the 20 g/kg DM limit.Graphical

Impact of High-Intensity Static Magnetic Field on Chemical Properties and Anaerobic Digestion of Sewage Sludge

The increasing production of sewage sludge at global level has addressed the search for technical solutions to take advantage from it, reducing the environmental burden originating from its disposal. Anaerobic digestion is a suitable option to handle sewage sludge in accordance with circular economy principles, as it generates a methane-rich biogas and a digestate with potential fertilizing properties. Several techniques have been proposed to enhance anaerobic digestion performances and, among these, the application of static magnetic field (SMF) has recently gained attention. Nonetheless, the effects of high-intensity SMF on the sewage sludge destined to anaerobic digestion and its impact on the anaerobic digestion process have not been evaluated yet. This study aims to determine the effects of a 1.5 T SMF on the chemical composition of sewage sludge as well as on methane generation during anaerobic digestion. The main parameters influencing the SMF (i.e., flow rate, mixing ratio of magnetized to non-magnetized sludge, number of pumping cycles, and total solid content) were varied to evaluate the impact of different exposure conditions on the chemical characteristics and methane potential of sewage sludge. An extensive exposure to the high-intensity SMF applied resulted in a 24% decrease of methane production, reduced the concentration of the monitored ionic species (i.e., NH4+, NO3−, PO43−, SO42− and Mg2+) in the liquid phase of sewage sludge, and promoted the precipitation of compounds with valuable fertilizing properties, e.g., struvite. These outcomes suggest that high-intensity SMF, although negatively influencing methane generation, can promote the precipitation, and possibly the recovery/recycle of valuable compounds from sewage sludge, enhancing its proper management in a circular economy perspective.Graphical abstract

Copper and Zinc Removal from Wastewater Using Alum Sludge Recovered from Water Treatment Plant

The study aimed to determine Aluminum sludge composition and structure for its valorisation as an alternative natural material for heavy metals removal from wastewater for further reuse as treated water in different applications. The study was conducted to investigate the introduction of Al-bearing sludge composition. The physical and chemical properties were examined using X-ray diffraction tests (XRD), scanning electron microscope tests (SEM), Fourier-transform infrared tests (FTIR), and Brunauer-Emmett-Teller tests (BET). Furthermore, the heavy metal concentrations of synthetic wastewater were measured using the spectrophotometry method. The experimental procedure is based on testing different pH limits and amounts of aluminum sludge to find the optimum conditions for copper (Cu) and zinc (Zn) removal. The results demonstrated a high removal efficiency where its value reached up to 97.4% and 96.6% for Zn and Cu, respectively, in an acidic medium (pH = 6) using a relatively high amount of sludge (1400 mg). Nevertheless, a low efficiency was obtained in the strongly acidic medium (pH = 4) and a smaller sludge amount of about 480 mg.

Feasibility of Thermal Utilization of Primary and Secondary Sludge from a Biological Wastewater Treatment Plant in Kaliningrad City

Hydrothermal liquefaction (HTL) of sewage sludge is considered in the article as an analogue of the natural processes of oil formation (catagenesis). A comparison of the physicochemical composition of primary and secondary sludge with type II kerogen (natural precursor of oil) showed their similarity. Both types of sludge have a slightly higher level of oxygen and nitrogen. The study tested the hypothesis that the elements included in the inorganic part of the oil source rocks can have a catalytic effect on the oil formation processes. For the conducted studies of sludge HTL, the catalysts containing cations and substances found in oil source rocks were chosen: as homogeneous catalysts (KOH, NaOH, NH4Fe(SO4)2, CoCl6, NiSO4, CuSO4, ZnSO4, MoO3) and as heterogeneous catalysts (MgO, Zeolite, Al2O3). The effectiveness of catalysts containing metal ions, zeolite and aluminum oxide has been proven. The highest biocrude yield was achieved in a process with NiSO4 as the catalyst in a dose 2 g per 10 g of sludge: oil yield increased by 34.9% and 63.4% in the processing of primary and secondary sludge, respectively. The use of catalysts provided an increase in fuel HHV by 10.8–12.5%, which is associated with a decrease in oxygen content (by 10.8–43.2%) with a simultaneous increase in carbon (by 7.9–10.9%) and hydrogen (by 6.5–18.7%) content.

Emerging applications of sludge biochar-based catalysts for environmental remediation and energy storage: A review

The discovery of carbon-based catalysts triggers a wealth of research towards metal-free catalysis. Various low-cost and earth-abundant biomaterials have been investigated to produce carbonaceous catalysts as they are a natural source of carbon and other functional elements. In recent years, sludge biochar as a catalyst has received considerable research interest because of its promising performance in advanced oxidation processes (AOPs) and energy storage devices (ESDs). Besides, it offers a cost-effective and environmentally friendly sludge valorization method that develops environmental processes based on circular economic principles. In this review, we systematically summarized the state-of-the-art nature of this technology, including catalysts synthesis routes, physicochemical properties , and applications in AOPs and ESDs. A relationship between carbonization factors and the development of catalytically active sites is presented with an in-depth discussion. The advantages and disadvantages of different modification processes are highlighted. In addition, scientific insight is given into various catalytic mechanisms during their applications. Eventually, we have outlined the challenges and prospects of this emerging field. Along with covering the advances in this research, this review comprehensively documented the sludge biochar application in ESDs for the first time. • The innate composition of sludge is beneficial for catalyst preparation. • Sludge biochar engineering renders ultra-high surface area and rich active sites. • Optimized sludge biochar performs promising catalysis reactions in AOPs and ESDs. • Catalytic mechanisms and active sites' roles are elucidated. • Challenges in SB-based catalysis can be overcome, and it has a bright future.

Performance of Mortar Incorporating Heat-Treated Drinking Water Treatment Sludge as a Silica-Sand Replacement

This paper examines the possibility of using water purification wastes in the production of mortar. Within the study context, XRD and XRF analyses were performed to obtain the chemical composition of sludge. Moreover, heat-treated sludge at a temperature of 900ºC was used in the preparation of mortar mixes as a partial sand replacement (5, 10, 15, and 20% by sand weight) with a w/c of 0.48. Fresh mortars were tested for workability, and mortar samples with 7, 28, and 90 days curing ages were tested for dry density, absorption, ultrasonic pulse velocity (UPV), and compressive and flexural strengths. Besides, some regression modeling was conducted for each of the measured parameters. In general, the results showed that the use of up to 10% incinerated sludge by sand weight leads to a slight decrease in the workability and density of the mixture and a 10% increase in its strength. Nevertheless, mortars with sludge content of over 10% showed a significant increase in water absorption and a decrease in strength and other properties. Doi: 10.28991/CEJ-2022-08-08-08 Full Text: PDF

STUDY OF THE AERO-DISPERSION SYSTEM IN THE FERROALLOY WORKSHOP WORKING AREA

A large proportion of the gases from the process units in the casting and furnace bays of ferroalloy plants enter the production facilities, where they form a complex aerodisperse system. The resulting aerosols pose a great danger to the operating personnel due to the presence of toxic and carcinogenic components. To develop emission prevention and elimination methods, the sources of industrial aerosol formation during silicomanganese production, particle size distribution and chemical composition of the dust sludge, the behaviour of the gas-dispersed system in the working area have been analyzed. Scanning electron microscope TESCAN VEGA3 with microanalytical attachment Oxford X-Act was used to study the morphology of dust particles sediment. It was established that the aerodisperse system of the shop atmosphere consists of condensation aerosol with submicron particles of manganese and silicon oxides and dispersion aerosol generated mostly at the transportation and loading of charge materials. The behaviour of particles of silicon and manganese oxides, forming a part of the condensed aerosol in the workshop atmosphere was considered. The motion parameters of particles of various chemical compositions simulating compositions of condensation and dispersion aerosols typical of the working area atmospheric aerosol system were calculated. Time and velocity characteristics of aerosol condensation particles for silicon and manganese oxides of 0.1; 1 and 5 microns in diameter are provided.

Exploring the feasibility and potential mechanism of synergistic enhancement of sludge dewaterability by ultrasonic cracking, chitosan re-flocculation and sludge-based biochar adsorption of water-holding substances

A method based on sludge-based biochar (SBB) skeleton adsorption of water-holding substances coupled with ultrasonic (US) cracking and chitosan (CTS) re-flocculation was proposed to strengthen sludge dewatering. Combined conditioning can greatly improve the sludge dewatering performance, the specific resistance to filtration (SRF), capillary suction time (CST), cake moisture content (MC) of sludge were reduced by 92.98 %, 78.46 %, 16.35 %. By analyzing the Zeta potential, relative hydrophobicity, water distribution, particle size distribution, filtrate organic matter, and extracellular polymeric substances (EPS) composition and structure of sludge, it was found that US, CTS and SBB showed significant synergistic effects. US disintegrated sludge flocs and promoted the transformation of functional groups on EPS, breaking the bond between solid and water molecules, releasing some bound water and intracellular substances, which laid the foundation for SBB to adsorb water-holding substances. CTS reconstituted flocs and crosslinked with protein (PN) to form complexes, which changed the spatial conformation of proteins. SBB adsorbs the water-holding substances such as protein and polysaccharide (PS) released in the outer EPS, promotes the dissolution of inner EPS, further promotes the denaturation and transformation of protein secondary structure, and improves the hydrophobic expression of sludge. Moreover, the combined conditioning reduces the compressibility of sludge and improves the water filtration efficiency. US+CTS+SBB is a green and promising combination technology, which has a certain reference value for sludge deep dehydration.

Recycling of sewage sludge in clay-free thermal insulation brick: assessment of microstructure, performance, and environment impact.

Recycling municipal sewage sludge in fired bricks not only contributes to environmental protection, but is also an alternative to natural clay resource. The complex compositions of sludge have a great influence on the brick property. This work presents a systematical investigation on fired bricks made only with sludge and shale. The physicochemical properties of the raw mixtures, macroscopic performance, microstructure, and its evolution were quantitatively determined. The coordination between shale and sludge enables the blend of raw materials to achieve the desired gradation and plasticity. Although a reduction in compressive strength was observed, the open porosity was increased to 31.6% and thermal conductivity was reduced to 0.51W·(m·K)-1, indicating the benefit to the performance of lightweight thermal insulation bricks. The fitting results confirm the pore-forming effect induced by the organic matter in the sludge. The obtained bricks possess good performance, especially in thermal insulation properties, and environmental and economic benefits.

Adaptive regulation of activated sludge's core functional flora based on granular internal spatial microenvironment

A great deal of efforts has been put into studying the influence of the external macroenvironment for activated sludge to survive on microbial community succession, while granular internal spatial microenvironment should be given equal attention, because it is more directly involved in the information exchange and material transfer among microorganisms. This study systematically investigated the effects of granular microenvironment on spatial colonization and composition of sludge's core functional flora, and the corresponding difference of biological treatment performance. High content of extracellular-proteins (67.53 mg/gVSS) or extracellular-polysaccharide (65.02 mg/gVSS) stimulated the microbial flocculation and aggregation of 0.5–1.5 mm granules (GS) or 1.5–3.0 mm granules (GM), respectively, which was resulted from excellent cell hydrophobicity (59.26%) or viscosity (3.47 mPa s), therefore, constituted relatively dense porous frame. More hollow space existed in 3.0–5.0 mm granules (GL), which formed loose skeleton with 0.213 mL/g of total pore volume and 17.21 nm of average pore size. Combining scanning electron microscope images and fluorescent in-situ hybridization based microbiological analysis, aerobic nitrifiers were observed to wrap or surround anaerobic bacteria, or facultative/anaerobic bacteria were self-encapsulated, which created granule's unique microenvironment with alternating aerobic and anaerobic zones. GS has the most rich organic matter degrading bacteria and anaerobic heterotrophic denitrifiers, while GM and GL presented the greatest relative abundance of facultative and aerobic denitrifiers, respectively. The activity of dehydrogenase and nitrogen invertase of GM showed be 1.32–3.09 times higher than those of GS and GL, contributing to its higher carbon and nitrogen removal. These findings highlight the importance of granular microenvironment to adaptive regulation of activated sludge's core functional flora and corresponding pollutant removal performance.

The Effect of Comparison of Polypropylene Plastic Waste Composition and Paper Sludge On Fiber Reinforced Composite Panels of Sugarcane Bags on Mechanical Properties

Indonesia's landfills contain 15% of plastic waste. Of the total plastic waste, some are recycled and stored in the TPA. The remaining unmanaged will be wasted into the environment. Therefore, it is necessary to utilize waste so that it does not damage the environment, for example the use of waste into composite boards. Composite board made from polypropylene plastic wastepaper sludge and bagasse fiber. This study aims to see the effect of the composition of polypropylene plastic waste and the effect of paper sludge composition on the mechanical properties of composite panels. Composites are made using the hand lay-up method. The compositions used varied, namely 60% polypropylene plastic waste: 40% paper sludge, 50% polypropylene plastic waste: 50% paper sludge, 40% polypropylene plastic waste: 60% paper sludge with 2% bagasse fiber. Based on the results of research on the composition of polypropylene plastic waste of 60% and paper sludge composition of 40%, the highest tensile strength, compressive strength and hardness values were 11.86 N/mm2, 21.54 MPa and 6.33 HV. And the composition of plastic waste polypropylene by 40% and composition of paper sludge by 60% obtained the lowest tensile strength, compressive strength and hardness of 1.23 N/mm2, 9.77 MPa and 4.53 HV. From this study, it can be concluded that if the composition of polypropylene plastic waste is used more and more and the composition of paper sludge used is less, the value of mechanical properties will be higher. The value of the mechanical properties produced has met SNI

The Effect of Variations of Bagasse Sugarcane Fiber Composition with Plastic/Polypropylene Waste Matrix and Paper Sludge Filler on Acoustic Testing on Composite Panels

Noise can affect a person's health and comfort. Noise can cause mood disorders, anxiety, and stress. One of the efforts to control noise is the selection of acoustic materials. The utilization of these materials can use as panels that can muffle sound, thereby reducing noise. In this study, bagasse fiber, polypropylene plastic waste, and paper sludge were used as materials in the manufacturing of composite panels. The method used is the impedance tube method. The greaterzthe sound absorption coefficient, the betterethe material is used as a sound dampening material. In this study, the composition of polypropylene plastic and paper sludge was 40:60, and variations in fiber composition of 0%,1%,2%,3% of the total weight of the composite panel. The bagasse fiber used is a fiber that has been alkalized to a good mechanical interlocking between the fiber and the matrix.Based on the results, the highestasound absorptionrcoefficienteis 0.98 atea frequency of 8000 Hzsfor a 3% fiber composition. The lowest soundeabsorptionrcoefficient is 0.63 at arfrequency of 2000eHz, for a 0% fiber composition. The more fiber composition used in the composite panel, the higher the resulting sound absorption coefficient. More bagasse fibers can increase the pores and thickness of the composite panel so it can absorb the sound that passes through it. The greater the soundaabsorption coefficient, the better the materialeis used as sound material. All sample variations meet the standard requirements as noise materials in buildings, namely 0.15

Analysis of the Composition of Municipal Wastewater Sludge from Small Settlements in East Kazakhstan

Analysis of the Composition of Municipal Wastewater Sludge from Small Settlements in East Kazakhstan

Potential Economic and Environmental Benefits of Faecal Sludge Derived Compost and Char Briquettes: The case of Dar es Salaam, Tanzania

The concept of resource recovery, particularly from waste has recently gained much attention and popularity. The aim of this study was to quantify the potential economic and environmental benefits of recovering nutrients and energy from faecal sludge (FS). The empirical data were collected from three unplanned settlements of Dar es Salaam City at Keko, Kipawa and Manzese. Two scenarios were developed to recover nutrients and energy. The estimations of potential amounts of compost and char briquettes were performed by using the resource value mapping (REVAMP) tool. Results from REVAMP indicated daily economic benefits across the study areas ranging between 680 and 950 USD for energy and up to 7,000 USD for nutrients recovered, based on the faecal sludge composition. In general, FS derived compost was found more profitable than FS derived briquettes. The analyzed environmental benefits include saving the estimated to 5 hectares of forest area from being cut when substituting the use of wood charcoal with FS-derived briquettes. Since the composting process resulted to be more profitable option between the two, this study recommends the adoption and scaling up. However, guidelines and standards should be developed for proper practices.&#x0D; Keywords: Faecal sludge; resource recovery; resource value mapping; briquettes; compost; economic benefits; environmental benefits

Conceptual design and feasibility study of industrial sludge-based biosolid fuel production facility

Industrial sludge must be disposed of by incineration or storage methods. It is possible to produce energy by incinerating the sludge after drying. However, some sludges cannot be incinerated due to their low calorific value and/or high pollutant load. In this study, a novel process in which sludges with high calorific value and other sludges are mixed, dried and processed to produce solid fuel without using any additives is described. A technical and economic model of the process was established and feasibility analysis was carried out for different capacities. According to the results of the study, with the increase in capacity, the cost for the unit capacity and the return for the unit capacity increase. Most of the plant's income comes from waste disposal. When the investment is made with equity, the payback period is shorter than 2 years for wet feeding capacities of 1 ton/h and above. The cost of the investment increases more than 2 times when 50% of the investment cost is supplied by a bank loan. In this case, the payback period is also increasing. In order for the profitability of the facility to be sustainable, the composition and amounts of sludge produced in the region should be analysed. In this study, it is assumed that the types and amounts of waste that will come to the facility are capable of filling the facility's capacity and providing the required calorific value standards.