Sludge Components Research Articles

Aluminum dissolution processing for high-level waste sludges

ABSTRACT Treatment of tank waste at the Hanford Nuclear Reservation in Washington State is one of the largest environmental challenges facing the world today. Processing the actinide rich insoluble solids poses one of the greatest obstacles to achieving long-term stabilization of the tank waste. By volume, the largest insoluble component of sludge is aluminum much of which is in the Southeast quadrant and resulted from de-cladding waste from the PUREX process. The largest single component within these tanks is Gibbsite, Al(OH)3, which poses significant challenges for processing due to the fast-settling times and high solids loading associated with this material. This work describes the testing executed to enable effective and efficient processing of high aluminum waste streams. This work highlights changes in the physical properties of waste streams with high aluminum concentrations, resulting in slower settling rates and lower solids loadings. These changes were accomplished using low temperature (40 °C) aluminum dissolution for simulated tank sludge.

Исследование физико-механических свойств битумного вяжущего из нефтешламового гудрона для дорожного строительства

The authors consider the issues of utilization of oil waste in demand in practice for the production of bitumen binders widely used in road construction. To solve this urgent problem, it is necessary to study the chemical composition and physical and mechanical properties of the bitumen binder obtained from oil sludge tar. The aim of the study is to select the optimal conditions for the fractional separation of oil sludge components with the release of tar, as well as to determine the technological conditions for obtaining high-quality road bitumen from tar. A physico-chemical analysis of oil sludge samples was carried out. A step-by-step selection of the distillation product was carried out with its further physico-chemical analysis. The main technological parameters of bitumen binder production have been selected. The physical and mechanical properties of the obtained bitumen samples have been studied and their corresponding grades have been established in accordance with the standard in force in Kazakhstan. By the methods of infrared spectroscopy and high-performance liquid chromatography of tar samples, satisfactory indicators were obtained for the presence of asphaltene compounds that contribute to improving the quality of the road surface. The analysis of the research results showed the prospects of oil sludge processing technologies in order to obtain tar, the raw material for the production of road bitumen. The use of oil sludge as a raw material for the production of road bitumen is economically advantageous due to the relative cheapness of the product and the technological simplicity of the processes of distillation of oil waste and tar oxidation.

Leaching profile of per- and polyfluoroalkyl substances (PFAS) from biosolids after thickening, anaerobic digestion, and dewatering processes, and significance of protein, phosphorus, and selected ions

Batch leaching experiments were conducted to evaluate the release of forty per- and polyfluoroalkyl substances (PFAS) from sludge samples collected after thickening, anaerobic digestion, and dewatering processes at two wastewater treatment plants. The South District wastewater treatment plant (SDWWTP), which receives domestic wastewater and landfill leachate from a nearby landfill, and the Central District wastewater treatment plant (CDWWTP), which receives only domestic wastewater, were selected for this study. PFAS released into the aqueous phase were analyzed by sacrificial sampling after 1, 3, 7, 14, and 30 days. Results demonstrated rapid PFAS leaching, with the highest levels detected in biosolid leachates after just one day. Distinct differences were observed in PFAS composition and concentrations between the two treatment plants. Of the forty PFAS measured, nineteen were detected, with higher concentrations identified at SDWWTP. The input of landfill leachate to SDWWTP appears to have significantly contributed to the elevated levels of specific PFAS, particularly long-chain compounds, compared to the emerging short-chain PFAS found in biosolids. In addition to PFAS analysis, the compositions of the sludge samples, including total and volatile solids, protein, phosphorus (P), iron, aluminum, calcium, and magnesium, were also assessed. Spearman correlation analyses revealed moderate to strong relationships between PFAS levels in leachate and certain sludge components. For instance, correlations between P content and PFCAs and FTCAs were moderate (R2 = 0.45–0.76). In thickener sludge leachate, strong correlations were observed for FPrPA (3:3 FTCA), PFDA, and PFTrDA with P, with R2 values of 0.60, 0.53, and 0.54, respectively. In the digested sludge, correlations were found for PFHpA, PFDA, and PFNA (R2 = 0.45–0.76). Also, for digested sludge leachate, strong correlations were found between the individual compounds PFHpA, PFHxA, PFNA, PFOA, and PFPeA (R2 = 0.60–0.88). Predominant PFAS in leachate from biosolids were identified, including PFOS, FPePA (5:3 FTCA), PFPeA, PFBA, PFHxA, N-EtFOSAA, and 6–2 FTS.

Fundamentals Studies of Sludge Electrolysis Using Bovine Serum Albumin (BSA) as a Model Compound

The Haber-Bosch process is the main industrial practice for producing ammonia, known for its energy intensity. Current ammonia production is unsustainable, and the overuse of synthetic fertilizer has led to significant environmental impact in air, water, and soil. Organic waste, such as sewage sludge from domestic wastewater treatment plants represents a valuable resource for nitrogen recovery, containing approximately 6% nitrogen content (1) in dry basis.Electrolysis of waste activated sludge (WAS) has the potential to recover nitrogen from this slurry waste (2-3), where nitrogen is mainly present in the form of proteins constituting 30-40% of the total solids in sludge (4). Developing efficient electrochemical processes to valorize organic waste such as WAS is critical to achieving sustainability goals, protecting the environment, and enabling economic development and growth (5). While efforts have been made to employ sludge electrolysis at high to moderate voltages to mineralize the organic matter completely or partially, the optimal scenario for electrolysis would involve the selective transformation of sludge components into valuable products like ammonia and other nutrients that can be further separated as a fertilizer (4). However, the complexity of sludge components, such as proteins, their solubility, denaturation, and structural variability, presents one of the main challenges that needs to be addressed in the process.Given the complexity of real sludge, it is reasonable to begin with a model compound such as a protein to understand the fundamental behavior of the system. Bovine Serum Albumin (BSA) is a globular protein that contains approximately 15-17 percent nitrogen by weight. This protein is relatively inexpensive, readily available, and possesses appropriate structural complexity for fundamental studies. In this presentation, the most recent results for the electrochemical oxidation of BSA will be discussed, aiming to provide a better understanding of the mechanism of reaction of complex organic nitrogen compounds.Reference: D. Bolzonella, C. Cavinato, F. Fatone, P. Pavan and F. Cecchi, Waste Management, 32, 1196 (2012).M. Jafari and G. G. Botte, Frontiers in Chemistry, 10, 974223 (2022).M. Jafari and G. G. Botte, Journal of Applied Electrochemistry, 51, 119 (2021).K. Xiao and Y. Zhou, Journal of Cleaner Production, 249, 119373 (2020).C. Alvarez-Pugliese, D. Donneys-Victoria, W. J. Cardona-Velez and G. G. Botte, Current Opinion in Electrochemistry, 46, 101508 (2024)

Możliwość produkcji materiałów wtórnych z odpadów węglowodorowych

The utilisation and processing of crude oil sludge is one of the major global challenges. Therefore, it is necessary to justify the following scientific solutions in the field of oil sludge utilisation and processing worldwide: the study of the physicochemical properties of oil sludge in order to obtain construction grade bitumen; detection of dispersion of solid particles in the composition of oil sludge; development of the optimal technological parameters for the process of obtaining construction grade bitumen from oil sludge; establishing a correlation dependence between process efficiency and the environment, the content of light fractions in the sludge composition, the process temperature. In this work, oil sludge was diluted with a solvent in a ratio of 70:30, with light naphtha used as a solvent. A laboratory distillation column was used to separate the sludge into fractions, and the chemical composition of the oil sludge was investigated. Oil sludge consists of asphaltenes up to 4.2–4.5%, resins up to 21.0%; paraffin-naphthenic hydrocarbons up to 41.2%; monocyclic aromatic hydrocarbons up to 4.6%; bi- and tricyclic aromatic hydrocarbons up to 5.8%; polycyclic aromatic hydrocarbons up to 9.7%. The paper also presents the results of the change in the viscosity and density of the distillate fractions separated during the distillation of diluted oil sludge. Density and viscosity were measured using an areometer and a VPZh-4, respectively. One of the main components of the oil sludge is water. A series of experiments were conducted to determine the water content using the Dean and Stark method. In addition, the sulphur content in oil sludge diluted with solvents – light and heavy naphtha, heavy gas oil – was determined.

Fractional recovery of proteins and carbohydrates from secondary sludge from urban wastewater treatment plants

The secondary sludge of wastewater treatment plants is an abundant and problematic bacterial biomass that accumulates nutrients from wastewater, mainly as proteins and carbohydrates. Recent studies have focused on energy recovery of this biomass by anaerobic digestion to produce biogas. However, fractional recovery of the sludge components could increase its value and provide the basis for a biorefinery based on this waste. Since ≈ 40-60% of the bacterial dry weight is protein, this biomass could be an important source of functional peptides or amino acids, and the carbohydrates could be used to produce bioplastics or biofuels. This study compares chemical, physical and biological hydrolysis methods and their sequential and assisted combinations to recover proteins and carbohydrates from sludge. Ultrasound-assisted alkaline treatment provided the highest protein solubilization yield (97.2%) with low degradation, resulting in peptide recovery yields of 75.1% with sizes from 70-215 kDa, 40% of essential amino acids and purity of 35.3% with NaOH 1M. The hydrothermal-alkaline combination almost completely solubilized the proteins but not the carbohydrates (77.4%) with high degradation (52.6%). The hydrothermal-acidic combination achieved high carbohydrate solubilization (94%) and recoveries of glucose (63.6%) and xylose (12.6%) but low protein recovery (43.7%) as small size peptides.

Study on the Influence of Sludge Biochemical Characteristics and Treatment Conditions on Rheological Properties

Abstract In response to the differences in the organic matter, oil and other components of temporary sludge stored in different storage areas of Shanghai Lao-gang, which affect the long-distance transportation of sludge, a full range sampling was conducted on the temporary sludge. Based on the results of solid content measurement, the pH value, mineral oil, total nitrogen, organic matter content, total oil and other six selected sludge samples were subjected to biochemical testing, and one sludge sample was selected for drying and concentration treatment. At the same time, sludge rheological tests were conducted on the biochemical testing sludge samples and the concentrated sludge samples, and the impact of sludge biochemical characteristics and sludge concentration on sludge rheological characteristics was compared and analyzed, which provide reference for the construction process of temporary sludge transportation.

Studying the productivity of sewage sludge (SS) components for photocatalytic CO2 transformation to CO and methane

AbstractEnergy-efficient photocatalytic CO2 conversion to sustainable solar fuels is a promising approach for simultaneously resolving energy and environmental concerns. The increased growth of sewage sludge necessitates research and innovation to propose more commercially viable options for lowering the socioeconomic and environmental complications associated with its current treatment. Sewage sludge can be applied to valuable products or used as a feedstock for energy production. According to the characterization results, the sewage sludge contains several metallic oxides (M), including Ni, Al, Mn, and Cu, and semiconductors (Fe2O3 and ZnO). According to the proposed mechanism, ZnO acts as an electron conductor between the Fe2O3 and the active sewage sludge due to forming an n–n type heterojunction. Under visible-light irradiation, photocatalytic CO2 reduction of sewage sludge was investigated using a fixed bed reactor. The CO2 reduction produced CO and CH4, with production rates of 9.76 and 4.20 µmol g−1 h−1, respectively, via the electrical conductivity in the sewage sludge elements. Furthermore, the impacts of photocatalyst loading, system reforming, light effect and pressure range were examined, where the methane yield at 0.1 g was 4.23 and 2.26 times significantly higher than at 0.05 and 0.2 g, correspondingly. With catalyst loadings of 0.1 and 0.2 g, the mono-oxide productivity was 1.69 and 2.58, notably greater, respectively. Moreover, the best yield of the CO and methane was obtained by using 0.3 bar as pressure and 10% methanol in H2O/CO2 as a reducing agent. Finally, using sewage sludge to produce a solar fuel based on the presence of active metallic oxide and semi-conductor heterojunctions provides novel insights from molecular and engineering perspectives into converting CO2 to a green fuel using wastewater sludge. Graphical abstract

Interaction of poly dimethyl diallyl ammonium chloride with sludge components: Anaerobic digestion performance and adaptive changes of anaerobic microbes

The wide utilization of poly dimethyl diallyl ammonium chloride (polyDADMAC) in industrial conditions leads to its accumulation in waste activated sludge (WAS), thereby affecting subsequent WAS treatment processes. This work investigated the interaction between polyDADMAC and WAS components from the perspective of anaerobic digestion (AD) performance and anaerobes adaptability variation. The results showed that polyDADMAC decreased the content of biodegradable organic substrates (i.e., soluble protein and carbohydrate) by binding with the functional groups and then settling to the solid phase, thus impeding the subsequent utilization. Higher concentrations of polyDADMAC prompted an initial protective response of excreting organic substrates into extracellular environment, but its toxicity to archaea was irreversible. Consequently, polyDADMAC inhibited the processes of AD and induced a 30 % reduction in methane production with 0.05 g polyDADMAC/g total suspended solid (TSS) addition. Changes in microbial community structure indicated that archaea involved in methane production (e.g., Anaerolineaceae sp. and Methanosaeta sp.) were inhibited when exposed to polyDADMAC. However, several adaptive bacteria with the ability of utilizing complex organics and participating in nitrogen cycle (e.g., Aminicenantales sp. and Ellin6067 sp.) were enriched with the above dosage. Specifically, the decreased abundance of genes relevant to methane metabolism pathway (i.e., mer and cdh) and increased abundance of genes involved in metabolism of cofactors and vitamins (e.g., nad and thi) indicated the toxicity of polyDADMAC and the irritant response of microflora. Moreover, polyDADMAC underwent degradation in AD system, resulting in a 12 % reduction in 15 days, accompanied by an increase in the -NO2 functional group. In general, this study provided a thorough understanding of the interaction between polyDADMAC and WAS components, raising concerns regarding the elimination of endogenous pollutants during AD.

Resource utilization of coal-derived sludge and low-rank coal by multi-step thermochemical co-treatment method

Both coal-derived sludge and low-rank coal possess significant potential for resource utilization and have garnered considerable attention in recent years. The TG−DTG analysis method showed that the thermal conversion components of coal-derived sludge tended to migrate to coal and interacted with low-rank coal. The dewatering effect of low-rank coal on coal-derived sludge was investigated using the sludge-specific resistance to filtration (SRF) method. The results showed that the addition of coal promoted the transformation of interstitial water and surface water of sludge, especially the interstitial water to free water. Dewatering and deoxidation of low-rank coal and coal-derived sludge were realized by decarboxylation and C−O bond cleavage on benzene during hydrothermal co-treatment at 140−220 ℃. The average water content of hydrochar was 3.96 % after hydrothermal co-treatment, and its calorific value increased from 19.77 MJ/kg to 21.74 MJ/kg after hydrothermal co-treatment. Hydrothermal oil was produced during hydrothermal co-treatment. GC−MS analysis showed that the contents of N and S increased in the hydrothermal oil with the increase of hydrothermal temperature, indicating that the hydrothermal co-treatment can remove the impurity elements (such as N and S) contained in coal-derived sludge and low-rank coal. The pyrolysis experiments of the hydrochar at 600–900 ℃ showed that the hydrochar produced less pyrolysis gas and emitted less CO2 than the result without hydrothermal co-treatment. This study provided an effective strategy for the treatment and resource utilization of sludge and coal.

Rheological properties of thermally treated and digested sludge: Implications for energy requirements of pumps and agitators

Understanding sludge rheology and optimizing equipment performance is crucial for energy efficiency in wastewater treatment plants (WWTPs). This study examined sludge rheology after thermal hydrolysis pre-treatment (THP) at 60, 80, and 120 °C for 2 h, followed by anaerobic digestion (AD) at 37 °C for 20 days, and assessed impacts on pump and agitator performance. Post-treatment, sludge showed reduced viscosity and improved flowability, indicated by changes in Herschel-Bulkley parameters, enhancing pump and agitator efficiency, particularly at 120 °C. These rheological improvements were correlated to the solubilization of sludge components after THP and solids reduction after AD, highlighting the interconnectedness of rheology and treatment outcomes. Despite high heat demands, an energy balance showed that THP scenarios, especially at 120 °C, had lower energy requirements for pumps and agitators, leading to energy savings without increased heat consumption. These findings underscore the influence of rheological changes in improving energy efficiency in WWTPs.

Feasibility study of the paper sludge properties in manufacturing recycled filler

The mineralization of inorganic components in paper sludge offers potential for their re-use in various fields. This study synthesized carbonates based on the minerals present in paper sludge and aimed to investigate the control of particle size distribution and particle shape of the synthesized carbonates. First, the physicochemical and thermal properties of paper mill sludge and ash were evaluated using a spectrophotometer, XRF, and TGA. Paper sludge ash was obtained by incinerating the paper sludge, followed by a carbonation reaction using CO2 gas injection and pH neutralization to produce recycled fillers. The average particle size, crystal lattice structure, and morphology of the recycled fillers were analyzed using a particle size analyzer, XRD, and FE-SEM. The results indicate that the recycled filler produced from coating paper sludge exhibited similar brightness and morphology to conventional paper-based fillers, suggesting its potential to replace commercial PCC (Precipitated Calcium Carbonate). In contrast, the recycled filler manufactured using old corrugated container mill sludge was deemed unsuitable due to its low hydration activity.

Quaternization-based graft modification of straw fibers for conditioning the sludge dewatering performance.

Extracellular polymeric substances (EPS) are a critical influencing factor in sludge dewatering. Disrupting such EPS contributes to the release of bound water in sludge, enhancing the sludge dewatering performance. In This study, quaternized straw fibers that are destructive to the EPS structure and components in active sludge were prepared useing heterogeneous free radical graft polymerization. Straw fibers, dimethyl diallyl ammonium chloride (DMDAAC), ammonium persulfate (APS), and acrylamide (AM) were taken as the substrate, grafting monomer, catalyst, and cross-linking agent, respectively.The optimal processing conditions determined for the DMDAAC-based quaternization and graft modification of straw fibers were as follows: reaction temperature of 60 °C, reaction time of 5 h, 0.100 g of catalyst APS dosage per gram of straw, and 3.000 ml of DMDAAC dosage per gram of straw. The optimal processing conditions yielded 1.335 g of modified straw fibers per gram of straw, 33.67% grafting rate, and 31.70% substitution of the quaternary ammonium groups. The capillary suction time (CST) was conditioned from 243.3 ± 22.6 s in the original sludge to 134.5 ± 34.45 s. The specific resistance to filtration (SRF) was reduced from 8.82 ± 0.51 × 1012 m/kg in the original sludge to 4.59 ± 0.23 × 1012 m/kg.

Binding characteristics of heavy metal contaminations and sewage sludge DOM products: Determination based on complexing-variance partitioning analysis

Dissolved organic matter (DOM), known for its ability to influence the environmental geochemical behavior of heavy metals, is widely regarded as an eco-friendly substance for mitigating heavy metal pollution in the environment. Understanding the unique properties of DOM as a ligand is essential for comprehending its impact on the migration and toxicity of metal pollutants. In this study, sewage sludge composting DOM components were used as ligands for the biding of heavy metal contaminants. Parallel factor analysis (PARAFAC) and variance partitioning analysis (VPA) was employed to analyze the complexing properties. Four DOM components were found in sewage sludge composting products. The identified DOM components in sewage sludge showed significant complexing ability with Zn, Cu and Cr, rather than Pb. Furthermore, based on VPA analysis, the heavy metal contaminants-binding contribution scores of each DOM components showed that simple structure DOM component C1 showed high Zn, Cu and Cr-binding ability. However, high humification degree DOM components presented high stability which could be employed for long-term heavy metals contaminants control. These promising findings provide valuable insights into the distinct binding properties of various DOM components with contaminants. This characterization serves as a theoretical foundation to support efforts in heavy metals control.

Влияние химического состава биомассы на процесс агломерации в псевдоожиженном слое котлоагрегата Е-75-3,9-440 ДФТ

The combustion of biofuels in the fluidized bed is an attractive technology to process biomass. However, the technology of biomass combustion in fluidize beds is characterized by several problems associated with the agglomeration of bed material. The aim of the research is to study the influence of the chemical composition of biomass on the agglomeration process of the fluidized bed of the boiler unit E-75-3,9-440 DFT. The boiler burns a mixture of by-products of pulp and paper production to increase stability of the fluidized bed and the duration of boiler operation between periods of its deslagging. The study has tested two types of biomass burned in a mixture in a steam boiler unit E-75-3,9-440 DFT with a fluidized bed. The authors also have studied the samples of agglomerates, bed, and fly ash to find out more about the agglomeration process. The elemental composition of samples of bark-wood waste, sewage sludge, agglomerates and ash has been studied. Elements affecting the process of agglomeration of the fluidized bed have been identified. The results of the analysis have showed that essential ash- and slag-forming components in the sewage sludge are silicon, calcium, sulfur, and potassium, and in the bark wood waste the essential ash- and slag-forming components are calcium, potassium, and sodium. The main elements influencing the process of agglomeration of the fluidized bed are alkaline elements of potassium and sodium. The results obtained make it possible to predict the agglomeration of the fluidized bed, to select the fuel mixture in the proportion necessary to reduce the agglomeration process.

ИССЛЕДОВАНИЕ УТИЛИЗАЦИИ NI2+-СОДЕРЖАЩЕГО ОТХОДА В КАЧЕСТВЕ КАТАЛИЗАТОРА ПРОЦЕССА ОКИСЛЕНИЯ УГЛЕВОДОРОДОВ

The feasibility of utilization of spent galvanic solutions containing high concentrations of heavy metal ions as a catalyst for hydrocarbon oxidation process is shown. Characterization of the studied sulfur-alkaline wastewater (SAWW) and spent Ni2+-containing electroplating solution is presented. It is established that the sludge isolated as a result of joint treatment of SAWW from sulfide ions and spent Ni2+-containing electroplating solution from nickel (II) ions contains a significant amount of impurities of organic substances. The method of obtaining Ni2+-containing catalyst from the sludge obtained as a result of joint treatment of wastewater from chemical and galvanic production - high-temperature heat treatment at 900 °C is proposed. It is shown that 15 minutes heat treatment of sludge in air medium at 900 °C leads to almost complete removal of organic impurities from it. Diffractometric method established that the main component of heat-treated sludge is nickel (II) oxide. It has been experimentally shown that treatment of SAWW with an ozone-air mixture for 60 minutes leads to a decrease in the Chemical Oxygen Demand (COD) value by only 1604 mg O/dm3, which corresponds to a purification degree in terms of COD value equal to 11.9 %. Addition of NiO-containing sludge obtained from the joint purification of SAWW and spent Ni2+-containing galvanic solution in the concentration of 200 mg/dm3 allows to significantly intensify the process of oxidation of organic pollutants of SAWW. It has been established that the use of heat-treated NiO-containing sediment as a catalyst leads to a decrease in the COD value by 3438 mg O/dm3. At the same time the degree of purification by COD value reaches 28.1 %. It is revealed that the efficiency of treatment of SAWW by COD value as a result of ozonation process using the obtained heat-treated sludge is 16.2 % higher in comparison with non-catalytic oxidation.

Pressurized electro-osmotic dewatering treatment of sludge: focusing on the influences on nutrients for agricultural application

ABSTRACT Sewage sludge requires effective dewatering and high nutrients retention before disposal for agricultural application. Pressurized electro-osmotic dewatering (PEOD) process with low energy consumption can effectively remove water from sludge, but the influences of PEOD process on nutrients for agricultural application still lacks in-depth research. In this study, the influences of PEOD process on nutrients for agricultural application were investigated, including organic matter, nitrogen, phosphorus, potassium and silicon contents. Layered experiments were conducted to investigate the layered variation of nutrients in sludge and to understand the potential change mechanisms. The experimental results showed that PEOD process caused small losses (<10%) of organic matter and total phosphorus (TP) in sludge, but caused 11.2−18.4% loss of total nitrogen (TN). PEOD process also caused 18.6−27.0% loss of total potassium (TK) and over 80% loss of available potassium in sludge, and could weaken the potential salt damage during the agricultural application of sludge. Furthermore, the available phosphorus content of sludge in the anode area increased significantly after the PEOD process, indicating that PEOD process could enhance the phosphorus bioavailability of sludge in the anode area. Besides, PEOD process caused a slight loss of silicon components in sludge, but improved the long-term silicon dissolution and release ability of sludge. This work could expand the knowledge about the influences of PEOD process on sludge nutrients and provide scientific guidance for the agricultural application of PEOD sludge.

Construction of synthetic anti-fouling consortia: fouling control effects and polysaccharide degradation mechanisms

The physical states and chemical components of bulk sludge determine the occurrence and development of membrane fouling in membrane bioreactors. Thus, regulation of sludge suspensions can provide new strategies for fouling control. In this study, we used “top-down” enrichment to construct a synthetic anti-fouling consortium (SAC) from bio-cake and evaluate its roles in preventing membrane fouling. The SAC was identified as Massilia-dominated and could almost wholly degrade the alginate solution (1,000 mg/L) within 72 h. Two-dimensional Fourier transformation infrared correlation spectroscopy (2D-FTIR-CoS) analysis demonstrated that the SAC induced the breakage of glycosidic bond in alginates. The co-cultivation of sludge with a low dosage of SAC (ranging from 0 to 1%) led to significant fouling mitigation, increased sludge floc size, and decreased unified membrane fouling index value (0.55 ± 0.06 and 0.11 ± 0.05). FTIR spectra and X-ray spectroscopy analyses demonstrated that the addition of SAC decreased the abundance of the O-acetylation of polysaccharides in extracellular polymeric substances. Secondary derivatives analysis of amide I spectra suggested a strong reduction in the α-helix/(β-sheet + random coil) ratio in the presence of SAC, which was expected to enhance cell aggregation. Additionally, the extracellular secretions of SAC could both inhibit biofilm formation and strongly disperse the existing biofilm strongly during the biofilm incubation tests. In summary, this study illustrates the feasibility and benefits of using SAC for fouling control and provides a new strategy for fouling control.

Evaluation and Management of B3 Waste Sludge via the Sludge Oil Recovery (SOR) Program at PT. X Plaju

With the ever-increasing need for waste management solutions, PT. X Plaju is one of the entities that contribute to B3 waste production, a waste type characterized by its explosive, flammable, reactive, corrosive, and toxic properties. This research centers on the evaluation and management of B3 waste sludge, particularly at PT. X Plaju. The institution implements two licensed B3 waste control programs: the Sludge Oil Recovery (SOR) and used lubricant utilization programs. The SOR program, which focuses on recovering components from oil deposits or sludge, operates under the recovery principle. This study showcases the importance of the oil component in the oil sludge, emphasizing that it must constitute more than 20% of the total volume to be deemed suitable for refinery production. Our findings highlighted a water content of 28.32% within the waste oil sludge. Additionally, the ultimate analysis showcased carbon, hydrogen, and nitrogen compositions of 85.99%, 13.42%, and 0.21%, respectively, while the density was measured at 0.85 gr/cc. This research offers insights into the waste management practices of PT. X Plaju, emphasizing the potential of the SOR program in managing B3 waste effectively.

Components of sludge from municipal wastewater treatment plants and its evaluation for land application in JiUJiang city of China

Municipal sewage sludge has a potential for widespread application on land, but the implementation of new standards for the agricultural use of sludge in China support a cautious approach. The organic matter, nutrients, and heavy metals in sewage sludge from four municipal wastewater treatment plants in Jiujiang City of China were continuously monitored. The feasibility for its land use was analyzed from three aspects such as sludge nutrients, heavy metal pollution levels, and potential ecological risks in soil. The average content of Cd, Cu, Zn, Cr, Ni, Pb, Hg and As in the sludge of Jiujiang City are 1.85, 305.25, 764.48, 170.57, 42.45, 42.27, 0.59, 28.79 mg∙kg-1, which are less than or close to mean value of heavy metals in China (except As), and all meet the minimum standards of heavy metal content in the sludge according to Chinese Quality of sludge from municipal wastewater treatment plant (GB24188-2009). The maximum content of Cu, Zn, Cr, and As exceed the control standards of pollutants in sludge for agricultural use, and the maximum value of Cu and Cr are close to the limit of landscaping standards. The average contents of organic matter, total nitrogen, total phosphorus, total potassium, and total nutrients in sludge are 385.16, 34.14, 11.05, 7.87, 53.06 g∙kg-1, respectively. The organic matter content meets the limit value (no less than 200 g∙kg-1) of Chinese Control standards of pollutants in sludge for agricultural use (GB 4284-2018), and the total nutrients content meets certain content limit (no less than 40 g∙kg-1) of total nutrients in China’s organic fertilizer. The single-factor pollution index and Nemerow’s synthetic pollution index methods were used to assess the pollution of heavy metals. The heavy metal pollution indexes (PI) are in descending order: Cd &gt; Cu &gt; Zn &gt; Cr &gt; As &gt; Ni &gt; Pb &gt; Hg. The PI shows that Cd and Cu are in strong pollution level, Zn is in moderate pollution level, and As, Ni, Pb, Hg are in absolute safe level. The potential ecological risk levels of heavy metal are ranked in the following order: Cd&gt; Cu&gt; As&gt; Ni&gt; Zn&gt; Cr &gt; Pb. The monomial potential ecological risk coefficients reveal that Cd is in extremely strong ecological risk, Cu is in medium ecological risk and other heavy metals are in slight ecological risk. The results indicate that Cd and Cu are the main contributors to the pollution and potential ecological risks of heavy metals in soil, to which more attention should be paid during sludge disposal. Being rich in organic matter and inorganic plant nutrients，sewage sludge in Jiujiang City may be widely used on soil, but availability of potential toxic metals exceeding the limit value often restricts its uses. Before being harmlessly treated, the sludge in Jiujiang City should not be used on agricultural land and may be applied with highly caution on landscaping and land improvement, but it can be used as cover materials for co-landfilling.