Wastewater Sludge Research Articles

Comparative Analysis of Sewage Sludge Characteristics After Natural Deposition, Accelerated Aging, and Composting

This study investigated treatment methods for urban wastewater sludge, specifically examining natural drying over five years, accelerated freeze–thaw–drying cycles, and composting with and without a zeolite additive. The findings reveal that composting effectively stabilized the sludge while retaining essential nutrients crucial for agriculture. Notably, with the addition of 2% zeolite by total mass, approximately 40% of the total nitrogen was preserved. Adequate aeration during composting maintained acceptable levels of phosphorus compounds, with the phosphorus content expressed as P2O5 showing significant retention compared with the natural drying methods. Composting also demonstrated a substantial reduction in petroleum hydrocarbon concentrations, which decreased from 30 mg/kg to 3 mg/kg, thereby showcasing its potential for processing contaminated sludge. The inclusion of zeolite enhanced the nitrogen retention by an additional 10–20% compared with the composting without zeolite, aligning with previous studies on its effectiveness. While composting and thermal treatments, like accelerated freeze–thaw cycles, influenced the physical properties of the sludge—such as reducing the moisture content and altering the volatile substance concentrations—they did not significantly affect the heavy metal levels. Natural drying over five years resulted in reduced metal quantities, which possibly reflected changes in the wastewater characteristics over time. Given that the heavy metal concentrations remained largely unchanged, additional treatment methods are recommended when the initial sludge contains high levels of these contaminants to ensure the safe use of the final product as fertilizer. This study underscored the significant role of biochemical and microbiological processes during composting and natural drying in transforming sludge properties. Future research should focus on establishing upper contamination thresholds and exploring microbiological safety measures to enhance the viability of sludge reuse in agriculture, balancing nutrient preservation with environmental safety.

Developing a universal equation to estimate the mass of dewatered wastewater sludge during biological digestion at mesophilic and thermophilic temperatures

ABSTRACT A series of dewaterability tests were conducted on various types of sludges to establish a wholistic relationship between sludge water fractions. Sludge samples were obtained from batch and continuous sludge digesters, which were operated anaerobically and aerobically under mesophilic and thermophilic conditions. Dewaterability of the sludge samples and the distribution of water fractions were studied using centrifugation and thermal drying. Thickened waste activated sludge (T-WAS) contained 10–11 g bound water (BW)/g of total solids (TS), and it was more hydrophilic than primary and digested sludges. During anaerobic digestion, BW content fluctuated between and 2.14.24 g BW/g TS. However, aerobic digestion at 55 °C reduced the BW content of the mixed T-WAS + primary sludges from 3.7 to 2.14 g BW/g TS. A linear function was developed to correlate supernatant and BW mass fractions (R2 = 0.995). An equation was derived from the linear function to estimate the mass of dewatered sludge based on the TS concentration of the initial wet sludge. The developed expression is applicable to different kinds of wastewater sludges. It would be helpful for the designers and operators of sludge thickening and dewatering systems to use centrifugal separation.

Correction: Chow et al. Anaerobic Co-Digestion of Wastewater Sludge: A Review of Potential Co-Substrates and Operating Factors for Improved Methane Yield. Processes 2020, 8, 39

The journal is publishing this correction to update the name of the Academic Editor listed on this published paper [...]

The waste recycling approach for enhancing wastewater sludge dewaterability by using iron-mud (IM)/sawdust derived carbon composite

The dewaterability of wastewater sludge by the solid waste of iron-mud (IM)/carbon (IMS) composite prepared via the in-situ carbothermal reduction method was systematically studied in this paper. It investigated the effects of different IMS materials, IM dosages and stirring speeds on sludge dewaterability, including water content (WC), capillary suction time (CST), extracellular polymeric substances (EPS) contents and particle size. The results of dewatering tests demonstrated that IMS materials significantly enhanced sludge dewaterability, resulting in a reduction of 39.85% in CST and 13.26% reduction in WC in the dewatered sludge under optimum condition (IMS-3 dosage of 8% dry solids; stirring speed of 250 r/min for 30 minutes). Electron paramagnetic resonancec (EPR) and scavenging experiments were conducted to better understand the dewatering process mechanism. This results indicated that both hydroxyl radicals (•OH) and superoxide radicals (•O2−) collaborate during the dewatering process. Furthermore, analysis were performed on the particle size of sludge flocs and scanning electron microscopy (SEM) imaging of sludge morphology to reveal the synergistic effects of IMS treatment. A two-step mechanism involving oxidation and Fe(III)-based re-flocculation maybe explain the synergistic effect of IMS treatment. This novel recycle-based IMS composite approach offers a new management strategy for industrial solid wastes while enhancing the sludge dewatering efficiency.

Extraction and analysis of microplastics in wastewater sludges of a multi-product pulp and paper mill

Pulp and paper wastewater sludges are waste streams produced in major quantities across the world. The recycling of these organic sludges, for example to soil amendments, is desired in the circular economy but carries the risk of potential pollutants to be also introduced into the environment. Pulp and paper wastewater sludges have been scarcely studied matrices in the microplastic research due to their complex composition. In this study, we optimized an extraction process for microplastics from pulp and paper wastewater sludges, and quantified and characterized microplastics down to 20 μm in primary sludge and biosludge generated at the wastewater treatment plant of a multi-product pulp and paper mill in Finland. The occurrence of microplastics was high in primary sludge, 900–1600 microplastics g-1 dry weight, while the maximum number of detected microplastics in biosludge samples remained at 210 g-1 dry weight. Biosludge samples suffered from larger amounts of remaining solids after the extraction process, thus compromising the detection of smaller microplastics (<100 μm) and increasing the uncertainty related to the interpretation of the results. The most prevalent microplastic shape in all samples was fragment, and the most recurring polymer types were polyethylene and polypropylene, while a polystyrene-based copolymer represented approximately 10% of identified microplastics in primary sludge. The present study advances the development of microplastic analysis of the challenging pulp and paper wastewater sludges and brings novel information to the progressing discussion of their circulation potential.

Improvement of Phosphorus Removal from Wastewater Through Fermentation of Low-Concentrated Wastewater Sludge and Increased Production of Volatile Fatty Acids

This article presents the results of a two-stage study: the first stage involved assessing the dependence of the increase or decrease in the concentration of volatile fatty acids (VFAs) on external factors and then assessing the relationship between the VFA concentration in the supernatant after fermentation and the processing characteristics (temperature, mixing mode, alkalinity, pH, nitrogen and phosphorus content). The greatest increase in VFAs (content up to 285 mg/L in the supernatant) was achieved at a temperature in the range of 28 to 38 °C with constant mixing of the sludge. Based on the results of the second stage, a conclusion was made on the efficiency of using a particular substrate depending on the concentration of phosphorus phosphates in the incoming wastewater. The study results showed that 7.54 mg/L of phosphorus can be removed with a given probability (for activated sludge, raw sludge and wastewater). It is recommended to compensate for the excess of this concentration by dosing the acetic acid solution at a rate of 3800 meq/L of VFA per 1 mg/L of phosphorus phosphates. The literature does not contain any results of parallel studies of the operation of a controlled bioreactor with artificial external feeding and acidified VFA. The results of the study can be applied in planning sludge acidification systems in the technological scheme of wastewater treatment and sludge processing.

Properties and Potential Application of Urban Sewage Sludge as Construction Material in Da Nang City

Research on sludge properties makes an important contribution to the management and reuse of sludge for different purposes. In this study, 60 sludge samples were sampled from the urban drainage river system in Da Nang city and analyzed for their physical and chemical properties. The results show that the composition of the sludge samples are mainly sand, ranging from 52.2 to 90.1%, pH at slightly acidic to neutral levels, ranged from 4.3 to 6.8, total organic carbon content ranged from 1.1 to 6.0% and there was a large difference within samples. The content of Cl-, SO42- ranges from 0.07 to 1.92%. There were 45/60, 31/60, and 26/60 samples with Zn, Pb and Hg contents exceeding the national technical regulation on sediment quality (QCVN 43:2017/BTNMT), respectively, from 1.04 - 2.52, 1.02 – 1.61, and 1.4 – 5.8 times. The As and Cd contents in all research samples were lower than the maximum allowable level (QCVN 43:2017/BTNMT). Ag, Co, and Se content were undetected in all samples. 48/60 sludge samples had phenol content exceeding QCVN 43:2017/BTNMT by 2.38 - 6.91 times. With this result, urban wastewater sludge in Da Nang city could be reused as bricked construction materials for a circular economy.

A meta-analysis of the impact of water-solved pollutants on the protein content of Pistia stratiotes L.

Due to the high cost of conventional water cleaning procedures, an affordable alternative for developing countries is the use of Pistia stratiotes L. Although these plants adsorb toxic chemicals in their tissues, other studies report a high protein content in its biomass and propose to use it as a fodder or even for human consumption. Therefore, this study aimed to identify the impact of water-solved pollutants on the content of protein in the tissues of P. stratiotes through a meta-analysis of currently available literature. Scientific reports, which included the biochemical analysis of the species when exposed to pollutants in the growing media were retrieved. The statistical analysis identified that chromium, wastewater sludge from a sugar factory, fluoride and linear alkyl benzene sulphonate reduce the content of protein. On the contrary, metals such as copper and zinc showed a slight tendency to promote the accumulation of protein in the biomass. Only the use of municipal wastewater sludge consistently promoted the increase of protein. Since most pollutants reduced the protein content and others also pose a bioaccumulation risk, P. stratiotes is not recommended to be considered as a fodder or to be included in human diet without previously ensuring its chemical innocuity.

Innovative Circular Biowaste Valorisation—State of the Art and Guidance for Cities and Regions

The management of the organic fraction of municipal solid waste (OFMSW), also called urban biowaste, and urban wastewater sludge (UWWS) represents a challenge for cities and regions, which want to adopt innovative urban bioeconomy approaches for their treatment and production of high-added-value products beyond the traditional anaerobic digestion (AD) and compost. This adoption is often restricted by the availability and maturity of technologies. The research object of this manuscript, based on the findings of EU Horizon 2020 project HOOP, is the identification of state-of-the-art circular technologies for material valorisation of OFMSW and UWWS, following a novel screening methodology based on the scale of implementation (tested at least at pilot scale). The screening resulted in 25 technologies, which have been compared and discussed under a multidisciplinary assessment approach, showing their enabling factors and challenges, their current or potential commercial status and their compatibility with the traditional technologies for urban biowaste treatment (composting and AD). The bioproducts cover market sectors such as agriculture, chemistry, nutrition, bioplastics, materials or cosmetics. Therefore, the results of this review help project promoters at city/region level to select innovative technologies for the conversion of OFMWS and UWWS into high value products.

Sustainable enhancement of biogas production from a cold-region municipal wastewater anaerobic digestion process using optimized sludge-derived and commercial biochar additives

Anaerobic digestion (AD) of municipal wastewater sludges produces valuable solid digestate and biogas. Biogas is a source of clean energy and enhancement of its production has been of recent interest for increased electricity generation, among other products. The objective of this study was the development of a novel municipal sludge-derived biochar and its application in a municipal wastewater AD system to increase the biogas production rate. Thickened waste-activated sludge (TWAS) samples were collected from the cold-region municipal wastewater treatment plant and used to synthesize biochar applied in the simulation of AD processes using laboratory-scale reactors. The TWAS-derived biochar was synthesized using the commonly used furnace pyrolysis (sludge-based biochar, SBC), and more novel microwave pyrolysis including phosphoric acid as a microwave activator (activated sludge-based biochar, ASBC). The microwave pyrolysis conditions were optimized using a computational fluid dynamics (CFD) technique. In addition, various commercially available carbon-based additives were assessed for their impacts on the AD process including activated carbon, wood-derived biochar, and forest residue-derived biochar. Results showed that the ASBC increased the cumulative methane production by 50% (333 mL/g VS) versus the control sample (221 mL/g VS) after 30 d. The ASBC showed higher surface area, electrical conductivity, and metal contents versus the other biochars which boosted the AD microbial community growth leading to higher organic matter conversion into biogas. In the ASBC-amended digesters, the bacterial phylum Bacteroidota, which contains a major genus of the dgA-11-gut-group, exhibited a synergy between organic substrate fermentation and volatile fatty acid production, resulting in enhanced biogas production. The TWAS biochar demonstrated promising performance in enhancing the AD process fostering energy and resource self-sufficiency at municipal wastewater treatment plants. This smart sludge management aligns well with sustainable waste management practices and clean energy production strategies, especially considering that the biochar was sourced from a readily available continuous waste-product stream.

Testing Pellets Fuel Production from Sewage Sludge of Palm Oil Industry

The wastes from the palm oil production process were used in this study, such as wastewater sludge and cake decenter or decanter waste. That moisture was less than 40% and increased density by the cold pelletizing process. The aim is to use pellet fuel for heating. Analysis of pellet fuel consists of physical properties, proximate (moisture, ash, volatile matter and fixed carbon) and heating value. The results showed that cake decenter and wastewater sludge had similar high volatile matter. The decenter cake had a higher heating value than the wastewater sludge at 26.649 and 14.965 MJ/kg, respectively. The ash of decenter cake was lower than wastewater at 11.71% and 22.34%, respectively. Blending both raw materials for pelletization increased the volatile matter that did not mix with another material. Therefore, both materials can be used to produce pellet fuel that has an optimal shape and size. That was hard to break. The results of chemical property testing show that it is within acceptable limits and can be used as pellet fuel.

Case specific: Addressing co-digestion of wastewater sludge, cheese whey and cow manure: Kinetic modeling

The study investigated the methane production efficiency in a semi-continuous laboratory experiment with periodic feeding of wastewater sludge (WWS) as primary substrate and addition of whey (CW) and cow manure (CM). The short-term behavior of a real-scale anaerobic digester with WWS and the methane production improvements with different feeding mixtures of WWS, CW and CM were addressed. Gradual addition of CW to WWS (WWS:CW:CM = 70:20:0 to 70:55:0) increased the average daily methane production to 48.6 mL CH4/g COD/day and prevented reactor failure, but high VOA/TIC values showed that the reactors were conditionally stable evolution at an OLR of 8 g COD/L/day. Reactors that were additionally supplemented with CM (WWS:CW:CM = 70:55:10) achieved at least 12.3 % more methane than the reactors supplemented with WWS and CW alone. The highest methane production and process evolution in the reactors were achieved at OLRs between 7.5 and 8.7 g COD/L per day. After day 50, the addition of double the amount of CW further increased the methane production and VOA/TIC ratios. In this case, the OLR increased from 6.3 to 9.3 g COD/L/day. The concentration of propionic and acetic acid in all reactors increased above the recommended values and caused inhibition and instability. A strong positive Pearson correlation was found between the trace elements (Fe, Cu, Zn, Mn) detected by XRF. TE contributed to methane production, but to a lesser extent than TIC and NH4+-N. The simplified model successfully predicted methane production under a periodic feeding regime.

Optimization of synthesis of cationic starches for wastewater sludge and microalgae separation

The implementation of stricter water protection legislation requires the development of novel environmentally friendly water treatment materials. A new method for the preparation of water soluble cationic starch flocculants using potato starch, 3-chloro-2-hydroxypropyltrimethylammonium chloride and CaO additive was developed and surface response methodology was successfully utilized for the optimization of degree of substitution in the cationization of potato starch with and without CaO additive. Based on the results of destabilization studies of model kaolin, wastewater sludge, and microalgae dispersion systems, optimized conditions ware proposed for obtaining an efficient, soluble, and biodegradable cationic starch flocculant with optimal structure. The duration of starch etherification reaction was reduced to <12 h to obtain soluble cationic starch derivatives with a degree of substitution of quaternary ammonium groups of 0.25, which retained the granular structure during synthesis. An efficient flocculation technology using anionic polymer and high content of biodegradable cationic flocculant was proposed. The highly efficient flocculation of microalgae suspensions using developed cationic starch derivative with the degree of substitution of cationic groups of 0.25 has been also achieved. The developed environmentally friendly cationic starches with tailored flocculation properties proofed to have a great potential in various water cleaning and separation technologies with prospects in wastewater treatment, agriculture or energy sectors.

Feedstock-dependent antibiotic resistance gene patterns and expression profiles in industrial scale biogas plants revealed by meta-omics technology

This study investigated antimicrobial resistance in the anaerobic digesters of two industrial-scale biogas plants processing agricultural biomass and municipal wastewater sludge. A combination of deep sequencing and genome-centric workflow was implemented for metagenomic and metatranscriptomics data analysis to comprehensively examine potential antimicrobial resistance in microbial communities. Anaerobic microbes were found to harbour numerous antibiotic resistance genes (ARGs), with 58.85% of the metagenome-assembled genomes (MAGs) harbouring antibiotic resistance. A moderately positive correlation was observed between the abundance and expression of ARGs. ARGs were located primarily on bacterial chromosomes. A higher expression of resistance genes was observed on plasmids than on chromosomes. Risk index assessment suggests that most ARGs identified posed a significant risk to human health. However, potentially pathogenic bacteria showed lower ARG expression than non-pathogenic ones, indicating that anaerobic treatment is effective against pathogenic microbes. Resistomes at the gene category level were associated with various antibiotic resistance categories, including multidrug resistance, beta-lactams, glycopeptides, peptides, and macrolide-lincosamide-streptogramin (MLS). Differential expression analysis revealed specific genes associated with potential pathogenicity, emphasizing the importance of active gene expression in assessing the risks associated with ARGs.

A Novel Approach for Rapid Dewatering of Water-Based Ink Wastewater Sludge under Low Temperature and Its Mechanism

A Novel Approach for Rapid Dewatering of Water-Based Ink Wastewater Sludge under Low Temperature and Its Mechanism

The fate of severe acute respiratory syndrome coronavirus-2 and pepper mild mottle virus at various stages of wastewater treatment process

This study investigated the efficiency of the treatment processes of wastewater treatment plants (WWTPs) to remove severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and pepper mild mottle virus (PMMoV) from the wastewater and sewage sludge, as well as the influence of the mode of operation on the quality of the treated wastewater. SARS-CoV-2 and PMMoV were detected and quantified at different stages of the wastewater and sludge treatment process of three major WWTPs in Stockholm, Sweden. The results showed that primary, biological, and advanced membrane treatment processes are effective in removing SARS-CoV-2 from the wastewater with removal efficiencies of 99–100 % for all WWTPs, while the virus was accumulated in the primary and waste-activated sludges due to higher affinity to biosolids. Operation strategies such as bypass reintroduced the virus into the treated wastewater. The WWTPs achieved relatively low PMMoV removal efficiencies (63–87 %) most probably due to the robust capsid structure of the virus. Anaerobic digestion could not completely remove SARS-CoV-2 and PMMoV from the sludge leading to increased levels of SARS-CoV-2 and PMMoV in dewatered sludge. The study gives an overview of WWTPs’ role in tackling pathogen spread in society in the event of a pandemic and disease breakout.

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

Thermal Inertia Performance via TRNSYS Software of Recycled Wastewater Treatment Plant Sludge as a Construction Material Additive to Ecological Lightweight Earth Bricks

This research investigates the thermal performance of earth bricks made with different percentages of wastewater sludge additive (0%, 1%, 3%, 7%, 15%, 20%) in terms of cooling and heating loads, time lag and decrement factor. The simulation of a reference house (2.5m,10m,6m) using TRNSYS software allows for the evaluation of these parameters, external wall thicknesses, bulk density, thermal conductivity, and specific heat capacity are employed as inputs in dynamic thermal inertia model. The results showed that the use of bricks with higher sludge additive percentages resulted in a drop in cooling and heating loads, the lowest cooling and heating loads of 1720 KWH and 1534 KWH respectively were recorded with the highest percentage of wastewater sludge additive of 20% and the biggest wall thickness of 30cm, it was also noted that the use of higher wastewater sludge additive percentages and bigger wall thicknesses led to higher time lags and lower decrement factor, the highest time lag of 15 hours and the lowest decrement factor of 0.019 were as well recorded with the highest wastewater sludge additive of 20%, and the biggest wall thickness of 30cm. These results were attributed to the higher specific heat capacity, and lower thermal conductivity of the bricks with higher wastewater sludge additive percentages.

The phagotrophic growth of algae on bacteria and its potential for wastewater and waste sludge treatment

Algae exhibit diverse growth strategies, including phototrophy, osmotrophy, and phagotrophy. While phototrophic and osmotrophic growths have been extensively studied, phagotrophic growth remains relatively unexplored. This research delves into the phagotrophic growth of Ochromonas danica on bacteria, evaluating its potential for wastewater and waste sludge treatment. The study reveals that O. danica was able to grow on bacteria without light or additional nutrients, achieving a doubling time of 3.5–3.9 hours and converting 41–45 % of bacterial organic matter into algal biomass. The resultant O. danica cells were lipid-rich, containing 35–46 % lipids by dry weight. The efficiency of O. danica in treating waste sludge was highlighted, achieving a 43 % reduction in organic matter within 36 hours, outperforming conventional aerobic digestion. The study also highlights the potential of O. danica in wastewater treatment. An approach was developed to reclaim organic matter from wastewater through a two-stage process, in which bacteria were first grown on wastewater organic matter and then the grown bacteria were fed to O. danica for growth. Results show that a total of 78.2 % of the initial wastewater organic matter was removed through this approach and 27.3 % of the removed organic matter was converted into lipid-rich algal biomass. The findings underscore the potential of phagotrophic growth for waste treatment and lipid production. The simplicity of the phagotrophic process, independent of light or complex nutrient supplementation, positions it as a promising strategy for industrial applications in waste sludge and wastewater treatment.

Assessment of photocatalytic activities of layered double hydroxide@petrochemical sludge biochar for sulfamethoxazole degradation

Layered double hydroxides (LDHs) as one of the popular photocatalysts have the drawbacks of compact structural arrangement and pronounced nano-particle clustering, which affect their photocatalytic performance for the degradation of organic pollutants from water or wastewater. Using biochar as a substrate matrix to support LDHs may be a good way to improve the photocatalytic performance of LDHs by avoiding agglomeration effect, promoting the separation of photogenerated electrons from holes for organics degradation. In this study, the composite of CoFe-LDH and petrochemical sludge biochar (CoFe-LDH@PBC) was fabricated and applied for the first time as photocatalyst for catalytic degradation of sulfamethoxazole (SMX). Results showed CoFe-LDH@PBC800/UV system exhibited excellent photocatalytic activity on SMX degradation than single CoFe-LDH/UV, PBC800/UV, or PBC105/UV system under various reaction conditions (photocatalyst dosage, pH, system speed, and SMX concentration). 100 % of SMX degradation efficiency and 88.98 % mineralization efficiency could be achieved in CoFe-LDH@PBC800/UV system within 100 min. The corresponded pseudo-first-order kinetic rate constant (kobs) of SMX degradation in CoFe-LDH@PBC800/UV system was 0.032 min−1, which was 3.20, 8.00, and 2.46 times higher than that of CoFe-LDH/UV, PBC800/UV, and PBC105/UV, respectively. In photocatalytic process, OH, O2−, and h+ participated in SMX degradation, among which h+ or OH played a major role. The good photocatalytic performance of CoFe-LDH@PBC800 composite was related to its excellent physiochemical properties, such as lower band gap (2.39 eV), high graphitization degree, and high conductivity, enabling efficient e−/h+ separation of photocatalyst for SMX degradation. Four distinct pathways of SMX degradation were proposed based on DFT theoretical calculations and byproducts of SMX degradation identified by LC-MS. Additionally, results from recycling tests suggested CoFe-LDH@PBC800 composite possessed a favorable reusability and could be applied for photocatalytic degradation of SMX at least 3 times. Over all, CoFe-LDH@PBC800 composite was proved to be an efficient photocatalyst for antibiotic degradation in water or wastewater and the reuse of petrochemical wastewater sludge was expected to realize the concept of resourceful and high-value utilization of waste biomass.