Mixture Of Sludge Research Articles

Ash Transformation during Fixed-Bed Co-combustion of Sewage Sludge and Agricultural Residues with a Focus on Phosphorus.

This work investigates the ash transformation during fixed-bed co-combustion of sewage sludge mixtures with the agricultural residues wheat straw and sunflower husks, focusing on the fate of phosphorus (P) in the resulting ash fractions. The study aims to determine suitable process parameters for fixed-bed combustion of fuels previously investigated in single-pellet experiments. The pure fuels and fuel mixtures were combusted in a 20 kWth residential pellet burner while monitoring the flue gas composition, temperature, and particulate matter formation. Subsequently, the different ash fractions were collected and characterized by CHN, SEM/EDS, and XRD analysis. The results showed that co-combustion of sewage sludge and agricultural residues reduced the formation of particulate matter as well as the formation of slag. Co-combustion of sewage sludge with either agricultural residue resulted in a change in phosphate speciation, displaying higher shares of Ca and lower shares of Fe and Al in the formed orthophosphates as well as amorphous phases containing higher shares of K. The formation of K-bearing phosphates was hindered by the spatial association of P with Ca and Fe in the sewage sludge, the incorporation of available K in K-Al silicates, and the depletion of K in the P-rich melt phase. Compared to mono-combustion, co-combustion experiments showed the potential for improving the combustion performance and reducing the risk of slag formation. The outcome suggests that co-combustion is a feasible path to integrate waste streams in fixed-bed energy conversion with simultaneous formation of phosphates enabling P recovery.

Characterization of sewage sludge and biomass ash mixture as future geotechnical material

To reduce the environmental load due to waste generation, there is an urgent need of utilizing the industrial/municipal waste in the bulk. There is a large scope of utilizing the bulk amount of waste as geotechnical material. Several studies have been made to utilize the industrial waste such as fly ash, slag, red mud, mine overburden etc. as geotechnical material, however, the sewage sludge did not get much attention. So, this research has been presented as a preliminary study which includes the physical, chemical, and microstructural property of sewage sludge for futuristic geo-material. Further, the biomass ash has been added with the sewage sludge to know its effect. The test result shows that the sewage sludge contains high concentrations of chromium, mercury and nickel. Dewatered municipal sewage sludge (80%) stabilized with biomass ash (20%) was used as a soil amendment, to predict the behavior of soil under a controlled environment. The application of stabilized sewage sludge over soil sample resulted in a significant increase in pH and electrical conductivity of the soil sample. The effect of stabilized sewage sludge over macronutrients and micronutrients present in soil was also determined and the results of statistical analysis revealed that the usage of sewage sludge stabilized with biomass ash enhances the fertility of the soil.

Boosting butyrate and hydrogen production in acidogenic fermentation of food waste and sewage sludge mixture: a pilot scale demonstration

Within the urban scenario, the application of a biorefinery technology value chain can foster the conversion of different organic substrates into marketable and added-value products. In this work, a pilot-scale dark fermentation (DF) process has been carried out as a key step for volatile fatty acids (VFA) and hydrogen production from the liquid fraction of sewage sludge and food waste mixture. Six operating conditions have been monitored in terms of yield and process stability, by changing the hydraulic retention time (HRT) from 4 to 6 days and applying a short-term hyper-thermophilic hydrolysis (70 °C, 8 h) on the same feedstock mixture. A tubular centrifugation was utilized to remove part of the biosolids (driven to biogas production) before the DF step, which was applied on the soluble and/or colloidal organic matter only. The hydrolysis step favored the following acidification process, in which a fermentation yield up to 0.42 g CODVFA/g VS0 was achieved at 5 days as HRT. Hydrogen production (up to 34.4% v/v and 0.046 m3 H2/kg VS0) was positively affected by the hydrolysis application and by the decrease of the HRT, highlighting the possibility to produce biohythane in the modeled two-phases anaerobic bioprocess. On the other hand, without the application of the hydrolysis, a selective production of butyric acid (up to 75% COD basin) was achieved, furnishing a different valorization route for the chosen urban organic feedstock. Changes in operating conditions and performances were also reflected by the adaptation of the microbial community, whose characterization highlighted the occurrence of several fermentative microorganisms (e.g., Clostridiaceae, Ruminococcaceae).

Effect of superficial gas velocity on membrane fouling behavior and evolution during municipal wastewater treatment

Aerobic granular sludge membrane bioreactor (AGMBR) is a promising technology for wastewater reuse and membrane fouling mitigation. Superficial gas velocity (SGV) plays an important role in the efficient and stable operation of AGMBR. However, the effect of SGV on the membrane fouling behavior and evolution of AGMBR has not been reported, which was systematically investigated in this study. AGMBR with various SGVs was used to treat synthetic municipal wastewater, and more than 94.5% and 60.5% of organics and total nitrogen, respectively, were removed at all SGVs. Further, a larger SGV prolonged the AGMBR overall operation. Contents and physiochemical properties of foulants varied with SGV and transmembrane pressure (TMP). Micro-level analyses revealed that the proportion of pore-blocking resistance in total fouling resistance as well as the microbial community diversity in the sludge mixture or on the membrane surface increased with TMP and SGV. The correlation analyses demonstrated that decreasing the polysaccharide content of soluble microbial products, increasing the protein content of tight extracellular polymeric substances in the sludge mixture, and enhancing the relative abundance of Bacteroidia and Gammaproteobacteria were beneficial for mitigating membrane fouling. This study reveals membrane fouling evolution and provides theoretical guidance for the large-scale application of AGMBR in wastewater reuse.

Neural Image Analysis for the Determination of Total and Volatile Solids in a Composted Sewage Sludge and Maize Straw Mixture

Waste management is one of most important challenges in environmental protection. Much effort is put into the development of waste treatment methods for further use. A serious problem is the treatment of municipal sewage sludge. One method that is useful for this substrate is composting. However, it is reasonable to compost a sewage sludge mixed with other substrates, such as maize straw. To carry out the composting process properly, it is necessary to control some parameters, including the total solids and volatile solids content in the composted mixture. In this paper, a method for the determination of the total solids and volatile solids content based on image analysis and neural networks was proposed. Image analysis was used for the determination of the colour and texture parameters. The three additional features describing the composted material were percentage of sewage sludge, type of maize straw, and stage of compost maturity. The neural models were developed based on various combinations of the input parameters. For both the total solids and volatile solids content, the most accurate models were obtained using all input parameters, including 30 parameters for image colour and texture and three features describing the composted material. The uncertainties of the developed models, expressed by the MAPE error, were 2.88% and 0.59%, respectively, for the prediction of the total solids and volatile solids content.

CO2 adsorption mechanisms on activated nano-sized biocarbons: Investigation through in situ DRIFTS, quasi in-situ XPS and XRD

As the most economical and feasible technology, CO2 capture has attracted enormous attention in recent years. This study investigated the CO2 capture potential using nanoporous biocarbons derived from mixture of sewage sludge and pine sawdust through modification of ZnCl2 + CO2. ZnCl2 + CO2 activated nanoporous biocarbons exhibited higher surface areas, pore volumes, tunable microporosity, compared to the char obtained by ZnCl2 activation. The highest CO2 adsorption capacity of 179.7 mg/g was observed for ZnCl2 + CO2 modified biocarbons pyrolyzed at 700 °C (BC700C), with surface area of 1952 m2/g and micropore volume of 0.65 cm3/g, respectively. In order to advance current acknowledge on the transformation process during CO2 capture, in situ DRIFTS, quasi in-situ XPS and XRD, were employed for identifying the transformation composites of CO2 on nanoporous activated biocarbons. The presence of nitrogen especially pyrrolic-/pyridonic-N was found to be conductive to CO2 adsorption and carbonates were induced by mineralogical reactions during CO2 capture process. Furthermore, the physiochemical characteristics of nano-sized biocarbons, i.e., hydrophobicity and aromaticity, also positively correlated to CO2 adsorption. In general, it was found that BC700C exhibited superior selectivity of CO2 over N2, excellent recyclability (97.8%) after 6 consecutive adsorption–desorption cycles, suggesting the long-term practical potential. This strategy developed in the present work can provide a reference for future rational design of highly robust nanoporous biocarbons for CO2 capture applications.

Does the initial C/N ratio interfere with the performance of sewage sludge composting and cotton waste?

ABSTRACT The effects of the initial C/N ratio on the composting of sewage sludge and cotton residues are not reported in the literature. Understanding the main composting control parameters is essential for the good stabilization of these wastes. Therefore, this study sought to evaluate different initial C/N ratios for the composting of sewage sludge and cotton waste, aiming to find the ranges with the best performance for the process and quality of the final organic compost. In this sense, five mixtures of sewage sludge (S) and cotton residues (C) were prepared and composted with three replications for each treatment in a completely randomized design. Physicochemical parameters were evaluated during composting and in the final organic compounds. A Multivariate Principal Component Analysis (PCA) was applied to evaluate the agronomic quality of organic compounds. The thermal behaviour of the mixtures presented differences. The treatments 90C10S, 80C20S and 67C33S showed the highest EXI² index (3566.64, 3448.39 and 2738.89), longer duration of thermophilic phase (12 and 13 days) and better potential for maximum degradation (A) of organic matter (67.5, 61.2 and 65.6%C). The final compounds of 90C10S and 80C20S showed higher pH values (7.9 and 7.5) and higher CEC (123.6 and 114.0 meq/100 g OM). PCA showed similarity in the agronomic quality of organic compounds for 90C10S, 80C20S and 67C33S. The treatment 28C72S (initial C/N ratio of 16.6) presented final pH of 5.3 and did not meet the minimum limit required by Brazilian regulations. Initial C/N relations between 24.9 and 35.2 showed better stabilization of waste and final organic compound with better agronomic quality.

Effects of powdered activated carbon dosage on the performance of membrane bioreactors treating biochemical tail water

As a promising treatment technology for wastewater, the promotion of membrane bioreactors (MBR) is restricted by biological fouling. Among the measures used to mitigate membrane fouling, the addition of powdered activated carbon (PAC) to MBRs has been recognized as an effective practice. However, the effects of PAC dosage on the performance of MBRs that treat highly biochemical influent from wastewater treatment plants remain unclear. In this study, by investigating the treatment of biochemical tailwater by PAC–MBRs, we thoroughly analyzed the effects of PAC dosage on the contamination removal efficiency, membrane operation cycles, sludge mixture properties, and microorganism distributions. The results indicated that the addition of PAC enhanced the removal efficiency of MBRs depending on the contaminant of interest. For example, the removal efficiency of total nitrogen can be boosted from 30 % to 60 % with PAC addition, while the removal efficiencies of total phosphorus were comparable with or without PAC addition. Furthermore, the application of PAC in MBRs can prolong the duration of membranes by suppressing biological fouling. This was supported by the decreased microbial products, reduced smaller solid particles, and stronger stability of sludge particles. PAC addition also boosts the proportion of Proteus and decreases the proportion of Bacteroides, which helps to improve the removal efficiencies of contaminants. Finally, among the PAC dosages tested in our study, 1.5 g/L PAC was proposed as the optimal candidate for treating highly biochemical influents. For example, the corresponding time for transmembrane pressure to reach 0.03 MPa was 19 d at 1.5 g/L PAC, while these periods were 7 and 14 d at dosages of 0 and 0.5 g/L, respectively. Overall, the findings of this study will aid in the selection of optimal dosages for other systems with different types of influents.

The Impact of Sewage Sludge-Sweet Sorghum Blends on the Biogas Production for Energy Purposes

The paper presents research on the impact of adding various forms of sorghum to sewage sludge on the anaerobic digestion process. The use of liquid sewage sludge alone in biogas plants at wastewater treatment plants is inefficient due to the low total solid (dry matter) content of this substrate. The tests revealed that the production of methane in biogas is low and amounted to 17.9% (105.4 Nm3∙Mg−1, VS—volatile solid). Therefore, other substrates should be blended with sewage sludge to increase the total solid of the batch. Sorghum silage, sorghum pomace, and sorghum juice were added to the sewage sludge in various proportions during the research. As a result, the improvement of the biogas process, the stabilization of the biogas production curve, as well as the increase in methane yield were observed. The most biogas and methane were obtained from a mixture of sorghum juice (5%) and sewage sludge (664.8 Nm3∙Mg−1 VS and 53.9%, respectively). Biogas production from other substrates based on sorghum and sewage sludge ranged from 457.4 to 588.8 Nm3∙Mg−1 VS. For a mixture of juice (7%) and sewage sludge, the batch was acidified, and biogas production was only 281.5 Nm3∙Mg−1 VS. Studies have shown that intelligent blending of an alternative raw material (compared to traditional maize silage) with sewage sludge allows for similar biogas yields while maintaining a stable anaerobic digestion process.

Co-Gasification Synergistic Characteristics of Sewage Sludge and High-Sodium Coal.

A comprehensive study was conducted to assess the co-gasification characteristics of sewage sludge and high-sodium coal. As the gasification temperature increased, the CO2 concentration was decreased, and the concentrations of CO and H2 were increased, while the change of CH4 concentration was not obvious. As the coal blending ratio increased, the H2 and CO concentrations initially increased and then decreased, while the CO2 concentration initially decreased and then increased. The mixture of sewage sludge and high-sodium coal shows the synergistic effect of co-gasification, and the synergistic effect was to promote the gasification reaction positively. The average activation energies of co-gasification reactions were calculated by the OFW method, and the average activation energy initially decreases and then increases as the coal blending ratio increases. Both fluidized-bed gasification and thermogravimetric analyzer gasification show that the optimum coal blending ratio is 0.6. Overall, these results provide a theoretical basis for the industrial application of sewage sludge and high-sodium coal co-gasification.

The behavior of separation and enrichment of valuable metals during the synergistic processing of metallurgical dust and sludge via roasting in rotary kiln

The generation of ironmaking and steelmaking dust and sludge exceeds 100 million tons annually, and stacking critically pollutes the environment. The joint treatment of such wastes for recycling metals is a promising approach to resolving these problems. This study focused on the separation and enrichment of metals during the synergistic processing of blast furnace dust, electric arc furnace dust, and steel pickling sludge in a rotary kiln at high temperature. Research results indicate that Na2O, K2O, Rb2O, Cu2O, ZnO, CdO, PbO, Bi2O3, and Sb2O3 may be separated during roasting. Under optimized Zn removal conditions of 30 min roasting time and 1373 K roasting temperature, the removal percentages of Sn, Sb and Cu reach 91.9%, 97.2%, and 72.4%, respectively, while Bi, Rb and Cd are removed almost entirely from the mixture of dust and sludge. The removed metals condense before the flue gas outlet (330 K) and are concentrated in the Zn-rich powder. The concentrations of Sn, Sb, Bi, Rb, and Cd in the Zn-rich powder were 5–7 times those in the mixture. The synergistic treatment of metallurgical dust and sludge may facilitate the efficient separation and enrichment of certain valuable metals, and the methods may be extended to jointly processing the other solid wastes; however, HCl gas formation may complicate gas cleaning.

Investigation on Co-combustion characteristics and NOx emissions of coal and municipal sludge in a tangentially fired boiler

Using the current coal-fired power plant to treat sludge with large annual production is an efficient sludge treatment method. Nevertheless, the majority of the previous studies concentrated on sludge co-firing with low blending ratio and moisture content in utility boiler. Further analysis and discussion are necessary regarding the impact of sludge with high blending ratio and high moisture content on co-firing performance as well as the potential interactions between high moisture content sludge and coal during the co-firing process. The simulation results of the verified computational fluid dynamic (CFD) model can be regarded as numerical experiments. In the present research, CFD was used to analyze the co-firing characteristics of municipal sludge and coal in a 600 MW tangentially fired utility boiler. The impacts of sludge moisture content, blending ratio, blending strategy, and secondary air (SA) distribution on co-combustion characteristics and NOx emissions were investigated, and their potential synergistic effects were assessed. The co-firing of coal and sludge has little impact on the furnace outlet temperature while potentially lowering NOx emissions, provided that the net calorific value of the feeding of the mixture of sludge and coal is kept constant. The reduction of sludge moisture content can significantly improve co-combustion performance, but it also facilitates NOx production. Blending sludge from the position of the medium-upper burners can reduce the number of layers needed to burn the sludge in practical coal-fired boiler. Furthermore, the SA distribution has a major impact on the furnace outlet flue gas temperature and NOx content. The shrunk-middle type is the optimum scheme for SA distribution. This study contributes to a deeper knowledge of the actual co-firing of sludge and coal in the utility boiler and provides a possible theoretical foundation for the widespread, clean, and effective use of sludge.

Characterisation of ash particles from co-combustion of bark and sludges from pulp and paper industry

Recycling phosphorus from waste streams for fertilization purposes could contribute to a sustainable society. The production in the pulp and paper industry results in several waste streams, among others nutrient-rich sludges in different forms. This study presents a detailed chemical and 3D characterization of ash from co-combustion of bark and two types of sludges from a paper mill; mixed sludge and biosludge. The combustion performance was investigated for these experiments and advanced analysis methods were used to characterise the ashes to correlate chemical and physical properties relevant for nutrient recycling. The elemental composition was determined by energy-dispersive X-ray spectroscopy; dominating crystalline phases by X-ray diffraction; and morphology, porosity, pore size distribution and active surface area of the slag were analysed with synchrotron-based X-ray micro-tomography and image analysis. Slag was formed in all combustion experiments to a large extent with increasing amounts with a higher proportion of sludge. Nutrient amounts indicate that slag particles from co-combustion of both biosludge and mixed sludge can be useful either as a soil improvement directly or for recovery processes. Slag from combustion of 30 wt% biosludge and 70 wt% bark contained the highest amount of phosphorus, 9 at% on a C and O free basis. Evaluation of tomography data showed that discrete and open pores could be distinguished on a micrometre scale. The porosity of the slag varied between the replicates and fuel mixtures, on average between 17 and 23 vol% for the bark and sludge mixtures. Open pore volume displayed large variations, on average 39–56 vol% of the pores were open pores connected to the surrounding volume. For all samples, 90 % of the pores were small, with an equivalent diameter under 30 μm, but the largest pore volume (80–90 %) consists of pores with an equivalent diameter over 75 μm. In soils, pores with a minimum equivalent diameter over 30 μm generally transmit water and the smaller pores store water. The slag particles have relatively thick walls, with few pore openings to the surroundings, indicating that the slag needs to be pre-treated by milling or crushing before application in the soil.

Sewage Sludge Valorization for Collapsible Soil Improvement

The environmental problems caused by sewage sludge generated by the growth of the global population and urbanization are drawing the attention of the scientific community worldwide to the need of developing sustainable solutions to use that material. This work investigated the possibilities of using sewage sludge, generated in wastewater treatment plants, as a strategy to improve and stabilize collapsible soils. Different soil–sludge mixtures, with 5%, 10%, and 15% of sludge, were analyzed. For the characterization and analysis of the soil–sludge interaction, physical, chemical, and edometric experiments were performed. The results showed that the addition of sludge to the soil causes a void index reduction, improves particle packaging, and reduces soil collapsibility to the same specific dry apparent weights, i.e., showed to be a promising method for the improvement of collapsible soils.

Methane and Hydrogen Sulfide Production from the Anaerobic Digestion of Fish Sludge from Recirculating Aquaculture Systems: Effect of Varying Initial Solid Concentrations

Recirculating aquaculture systems (RAS) are efficient at solid waste capture and collection but generate a concentrated waste stream. Anaerobic digestion (AD) could be one potential treatment option for RAS facilities. However, the concentration of organic matter in the sludge can significantly affect the biogas quality from AD. This study evaluated the effect of fish sludge (FS) solid concentration on biogas quality. Three FS treatments consisted of different initial total solid concentrations (1.5%, 2.5%, and 3.5%) from a mixture of sludge produced by Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Methane (CH4) production was measured, quantified, and normalized on a volatile solids (VS) basis. The highest solid concentration treatment produced 23% more CH4 than the lowest solid concentration (519 mL/g VS versus 422 mL/g VS, respectively). Peak CH4 production occurred on Day 7 for the lowest FS concentration (78.2 mL/day), while the highest FS concentration peaked on Day 11 (96 mL/day). Peak hydrogen sulfide (H2S) concentrations ranged from 1803–2074 ppm across treatments, signifying the requirement of downstream unit processes for H2S removal from biogas. Overall, this study demonstrated that increasing the FS concentration can significantly enhance CH4 production without affecting the stability of the digestion process.

Development of Anaerobic Biodigester for the Production of Biogas Used in Semi-Continuous System Bioprocesses: An Efficient Alternative for Co-Digestion of Low Biodegradability Biomass

The objective of this work was to develop an automated anaerobic biodigester capable of operating in a semi-continuous or batch system for biogas production. Low biodegradability biomass has little efficiency in the production of biogas by anaerobic digestion processes and an efficient alternative is the use of bioprocesses in semi-continuous system. Two experiments were carried out in the same proportions but in different processes, and all control and automation parameters were tested and evaluated. For testing, mixtures of organic waste, anaerobic sludge (inoculum) and raw sewage without any treatment from the sewage treatment plant, in mesophilic phase (37 °C), were used during the 60 days of experiment. The semi-continuous system showed the greatest reduction in organic matter, expressed by the removal of 80.7% Total Solids Volatile (TVS) and the greatest volume (68.5 L) and methane percentage (78.5%). Finally, with these and other results found, it is possible to conclude that the biodigester developed for semi-continuous system, with the automation and control system, was satisfactory for the reduction in organic matter and biogas production. In addition, all operating system worked properly and with the use of current, low-cost technologies, the application and development on a larger scale becomes viable in the future.

Использование вермикультуры для переработки донных отложений, загрязненных нефтепродуктами

The vermiculture was kept in plastic containers on a mixture of sludge from oil mine treatment facilities and peat. It has been shown that bottom sediments contaminated with petroleum products can be used as a component of a vermicompostable mixture. During the processing process, the content of petroleum products in the composting mixture significantly reduced, but the level of reduction varied depending on the ratio of sludge and peat in the vermicomposting mixtures. The optimal mixture options for faster processing of the substrate include a mixture of contaminated sludge and filler in a ratio of 30:70 and 50:50. Reproductive performance of earthworms, as well as the increase in the number and biomass of juveniles, remains low in all variants of mixtures, but is close to optimal at a 30% content or in composted material.

Immobilization of heavy metals in tannery sludge by the formation of tobermorite in subcritical water treatment with rice husk silica.

Tannery sludge, heavy metals (HMs) enriched hazardous solid waste, is produced extensively in many regions of the world. Even though the sludge is hazardous, it can be considered a material resource, if organic matter and HMs in the sludge can be stabilized to minimize its negative environmental impacts. This research aimed to evaluate the efficacy of using subcritical water (SCW) treatment for tannery sludge treatment through immobilization and thus reduction of HMs to mitigate their potential environmental risk and toxicity. HMs in the tannery sludge were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and the average concentration of HMs (mg kg-1) was found in the following decreasing order of Cr (12 950) > Fe (1265) > Cu (76) > Mn (44) > Zn (36) > Pb (14) with very high Cr concentration. The result of toxicity characteristics leaching procedure and sequential extraction procedure tests revealed that the raw tannery sludge leachate contained 11.24 mg L-1 Cr, which classified the raw tannery sludge into a very high-risk category. After SCW treatment, the concentration of Cr in leachate was reduced to 1.6 mg L-1 indicating risk reduction to a low-risk category. The eco-toxicity levels of other HMs also decreased considerably after SCW treatment. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) analysis were employed to identify the effective immobilizing substances formed in the SCW treatment process. The favorable formation of immobilizing orthorhombic tobermorite (Ca5Si6O16(OH)2·4H2O) at 240 °C in the SCW treatment process was confirmed by XRD and SEM analysis. The results confirmed that the formation of 11 Å tobermorite is capable of strongly immobilizing HMs in the SCW treatment process. Further, both orthorhombic 11 Å tobermorite and 9 Å tobermorite were successfully synthesized by SCW treatment on a mixture of tannery sludge including rice husk silica and Ca(OH)2 with water under rather mild conditions. Hence, it can be concluded that SCW treatment of tannery sludge with supplementary silica from rice husk can effectively immobilize the HMs and significantly reduce their environmental risk through tobermorite formation.

STUDY ON THE EXTRACTION OF BLACK SOLDIER FLY (HERMETIA ILLUCENS) LARVAE OIL BY USING MECHANICAL PRESS METHOD

This study investigates the optimisation of Black Soldier Fly oil extraction from different feeding sources. The larvae are fed a mixture of pasta-tobacco waste (MPT) and fish-ball sludge (FS). The mechanical press method is used to extract the oil. The results showed that the MPT-fed larvae had a higher weight at 0.088 ±0.001 g compared to 0.062 ± 0.002 g for larvae fed with FS. The feeding rates revealed that the higher the dose of the feed, the more weight the larvae gained. Meanwhile, GC-MS results show that the MPT substrate has a higher number of characterised fatty acids than the FS substrate, with three predominant fatty acids being lauric acid (43.69%), palmitic acid (16.15%) and linoleic acid (12.35%). Fourier-Transform Infrared spectroscopy (FTIR) analysis for both substrates reveals a similar high absorbance but High-Performance Liquid Chromatography (HPLC) analysis shows glutamic acid to be the most abundant amino acid in both substrates. Additionally, the regression analysis shows that moisture content and feeding rate is the most important parameter. Response Surface Methodology (RSM) determined that moisture content and feeding rates were the best parameters for oil yield.

Analisis Kadar Air dan Kadar Abu Briket Lumpur IPAL dan Fly Ash dengan Penambahan Serbuk Gergaji Kayu

WWTP sludge which is the result of industrial wastewater treatment that has the potential for environmental pollution that must be managed by the industry concerned. utilization of waste sludge into briquettes can be an alternative that needs to be reviewed in order to improve energy efficiency. The purpose of this study was to determine the IPAL mud, fly ash, and wood sawdust can be used as alternative fuels in the form of briquettes, to determine the effect of variations of IPAL mud, fly ash, and wood sawdust on the quality of briquettes in the form of ash content and moisture content. Based on the results of the research that has been carried out, it can be concluded that the raw materials for WWTP mud, fly ash, and wood sawdust can be used as raw materials for making briquettes according to SNI 4931-2010 with type B briquette classification. All briquettes produced are included in the set standards because all briquettes research results show a figure of <5% which is certainly below the established quality standard, which is 12% in each briquette produced. Briquettes of a mixture of sewage sludge, fly ash, and sawdust with a concentration of 40%: 30%: 30% and an adhesive percentage of 20% have the highest ash content in each percentage of molasses.