Dried Sewage Sludge Research Articles

Effect of domestic dry sewage sludge on concrete compressive strength

The possibility of saving and sustaining natural materials by reusing waste is one of the most important goals researchers seek to achieve and prove its effectiveness and positive impact on the environment. In this study, domestic wastewater sludge was utilized in concrete production as partial cement changing with different ratios (0, 5, 10, and 15) % with dry sludge. The study showed that the compressive strength test showed that the partial replacement of cement by dry sludge caused reduction increased directly with the increase of sludge ratio compared with concrete reference specimens. The study found that dry sludge can be used up to 15% as a replacement in concrete sidewalks and roads because these applications use horizontal construction, which does not require the same high strength resistance as vertical construction. In addition, it was also found that using up to 10% dry sludge content in concrete may positively impact reducing sludge levels in the environment and the cost of cement production without a significant effect on the compressive and flexural strength of concrete. The study aimed to encourage government agencies and the business sector to employ excess quantities of domestic sludge in the construction industry, as well as to investigate the influence of partial replacement of cement with dry sludge on the compressive strength of concrete.

Carbon balance analysis of sewage sludge biochar-to-soil system

Converting sewage sludge (SS) into biochar via pyrolysis is proposed as a prospective strategy for recycling nutrients and reducing environmental risks. Yet, from the perspective of carbon (C) balance the viability of pyrolyzing SS still remains unclear. Here we quantified the C footprint of the whole process from raw SS pyrolysis to final disposal of SS-derived biochar (SSB) using life cycle assessment based on a 20-tonne industrial pyrolysis furnace and field experiments. Results indicated that about 0.101 tonnes of direct CO2 equivalent (CO2e) (from N-containing organic compounds in SS) plus 1.506 tonnes of indirect CO2e (from energy consumption and dewatering agents) were emitted for each tonne of dry SS treated during its dewatering and pyrolysis processes, and at least 0.252 tonnes of CO2e were sequestered as stable C in SSB, depending on the final application route of SSB. In contrast, the net C emissions from traditional SS treatments amounted to at least 2.432 tonnes of CO2e per tonne of dry SS under the similar scenarios. Converting SS into SSB thus showed great advantages in C balance over the traditional treatments of SS. Sensitivity analyses indicated that the moisture and C contents of SS and the usage of dewatering agents were the key factors affecting C balance in the SSB-to-soil system. These findings highlight the C sequestration potential of pyrolysis and provide important support for the optimization and management of SS treatment.

Enhancing the sustainability of high strength concrete in terms of embodied energy and carbon emission by incorporating sewage sludge and fly ash

This paper discusses the properties of dried sewage sludge (SS) and its influence on the microstructure development of HVFA concrete when used as a partial replacement of binder material. A detailed characterization of dried sludge samples collected from a sewage treatment plant is carried out using XRF, XRD, TGA, and FTIR techniques. HVFA concrete mix is designed for 50 MPa with 50% fly ash of the total binder content. Sludge is ground to a particle size of 150 µ and 75 µ and replaced at levels of 5%, 10%, and 15% of the total binder content. The strength activity index of the dried sludge sample is acceptable as per standards. Taking concrete mixes with HVFA as a reference, the fresh properties of binder paste and concrete with sewage sludge have been studied. Mechanical properties that define the applicability to various infrastructure projects are reported for all the studied mixes. EI, CI, COST per unit compressive strength for all mixes are also determined to comment on the environmental impact of the use of SS in concrete. The compressive strength of concrete specimens decreases with the increase in replacement level of SS. However, in comparison with OPC concrete, 75 µm SS at 5% replacement level concrete mechanical strength is within the acceptable limit for M50 concrete mix. The addition of SS as a binder to the concrete has a lower environmental impact, embodied energy, CO2 emission, and cost per unit strength. But more than 10% replacement level resulted in reducing CS, FS, and STS by 11.17%, 6.23%, and 6.99%.Graphical abstract

Integration of hydrothermal carbonization and aqueous phase reforming for energy recovery from sewage sludge

This study investigates the energy recovery from sewage sludge by combining hydrothermal carbonization and aqueous phase reforming of the generated process water. The hydrothermal treatment was carried out at 170 °C and 230 °C for 1 h, and produced a hydrochar with adequate physicochemical properties, such as a higher heating value (20–24 MJ kg−1) than sludge, improved fuel ratio (0.2–0.5) and a broad comprehensive combustion index (5.8 × 10−7 to 10.0 × 10−7 min−2 °C−3). Aqueous phase reforming of the process water was carried out at 220 °C and 25–29 bar for 4 h. A maximum H2 yield of 98.7 mmol H2 gTOC−1 was achieved using a bimetallic Pt/Rh catalyst supported on carbon black and for the process water obtained at the lowest carbonization temperature. The integration of hydrothermal carbonization and aqueous phase reforming processes is an interesting alternative for the management and energy recovery of sewage sludge, which allows reaching a potential energy recovery of 17.3 MJ per kg of dry sewage sludge, equivalent to 93.5 % gross energy recovery, under optimized conditions.

Microplastics removal from a primary settler tank in a wastewater treatment plant and estimations of contamination onto European agricultural land via sewage sludge recycling

Wastewater treatment plants (WwTPs) remove microplastics (MPs) from municipal sewage flow, with the resulting bulk of MPs being concentrated within generated sewage sludge which is frequently recycled back onto agricultural land as accepted practice in many European countries as a sustainable fertiliser resource. This circular process means that MPs successfully removed from WwTPs are deposited into the soil and able to return into the natural watercourse by means of run-off or infiltration to groundwater. This study quantifies the removal efficiency of MPs with size ranging between 1000 and 5000 μm in a primary settlement tank (PST) at a WwTP serving a population equivalent of 300,000 and provides MP concentrations in the generated sewage sludge. Our study revealed that the proportion of MPs partitioning in a PST to settled sludge, floating scum and effluent was 96%, 4% and 0% respectively, implying 100% removal of MPs of 1000–5000 μm in size. The generated sewage sludge was estimated to contain concentrations of approximately 0.01 g of MPs or 24.7 MP particles per g of dry sewage sludge solid, equivalent to ∼1% of the sewage sludge weight. Using these figures and data from the European Commission and Eurostat, the potential yearly MP contamination onto soils throughout European nations is estimated to be equivalent to a mass of MPs ranging between 31,000 and 42,000 tonnes (considering MPs 1000–5000 μm in size) or 8.6×1013–7.1×1014 MP particles (considering MPs 25–5000 μm in size). An estimated maximum application rate of 4.8 g of MP/m2/yr or 11,489 MP particles/m2/yr, suggests that the practice of spreading sludge on agricultural land could potentially make them one of the largest global reservoirs of MP pollution. Hence, recycling raw sewage sludge onto agricultural soils should be reviewed to avoid introducing extreme MP pollution into the environment.

Combining sequential extraction and 3D fluorescence to investigate the behavior of antibiotic and polycyclic aromatic hydrocarbons during solar drying of sewage sludge

Solar drying and liming are commonly used for sludge treatment, but little is known about their efficiency on antibiotics and Polycyclic Aromatic Hydrocarbons (PAHs) removal. This study aimed to investigate the removal of antibiotics and PAHs during solar drying of Limed Sludge (LS) and Non-Limed Sludge (NLS). Thus, organic matter fractionation and 3D fluorescence were used to assess the accessibility and the complexity of organic matter. 2 experiments have been conducted using LS and NLS for 45 days of drying in a pilot scale tunnel. Physicochemical results indicated significant decrease of water content (90%) for both sludge samples within 15 days of drying. For both treatments, the removal of total organic carbon and total nitrogen was low and similar for both treatments. Through this study, it has been confirmed that liming and drying contributed to a strong modification of the organic matter quality with an increase of its accessibility. On the other hand, drying alone increased the less accessible compartments, while the presence of lime affected the interconnexion between the organic matter pools. 3D fluorescence confirmed the obtained results and indicated that LS leads to obtaining more simple molecules in the most accessible compartments, while NLS leads to obtaining more complex molecules in the less accessible compartments. In addition, solar radiations and leaching may contribute to the significant removal (p < 0.01) of roxithromycin, benzo(a)anthracene, chrysene, benzo[k]fluoranthene, benzo[a]pyrene, and benzo(g, h, i) perylene in the presence of lime. Furthermore, the evolution of organic matter pools in terms of accessibility and complexity may drive the bioavailability of these pollutants, leading to their significant removal.

Preparation of Citric Acid-Sewage Sludge Hydrochar and Its Adsorption Performance for Pb(II) in Aqueous Solution.

In order to seek the value-added utilization method of sewage sludge and develop low-cost and high-efficient adsorbents, a hydrochar was prepared by the co-hydrothermal carbonization of sewage sludge and citric acid and then characterized. The differences in Pb(II) adsorption performance between the citric acid–sewage sludge hydrochars (AHC) and the hydrochar prepared solely from sewage sludge (SSHC) were also investigated. When citric acid dose ratio (mass ratio of citric acid to dry sewage sludge) is 0.1, the obtained hydrohcar (AHC0.1) has the highest specific surface area (59.95 m2·g−1), the most abundant oxygen-containing functional groups, the lowest pHpzc (5.43), and the highest equilibrium adsorption capacity for Pb(II). The maximum adsorption capacity of AHC0.1 for Pb(II) is 60.88 mg·g−1 (298 K), which is approximately 1.3 times that of SSHC. The potential mechanisms can be electrostatic attraction, co-precipitation, complexation, and cation-π interaction. It was demonstrated that by incorporating citric acid into the hydrothermal carbonization, resource utilization of sewage sludge can be accomplished effectively.

Solar pyrolysis tars treatment using oxidation processes – Efficiency and toxicity analysis

This paper presents oxidation and photocatalytic oxidation as the methods for elimination of toxic activity of biomass pyrolysis liquids subjected to the environment – water. With the increasing interest in biomass pyrolysis-derived fuels and chemicals, there is still a need for determining the environmental impact of unwanted leakage of the pyrolysis liquids to the environment via inappropriate handling or containers damage and proposing adequate solutions to solve it. Tars from solar pyrolysis of three biomass types (waste straw – WS, wood chips – WC, and dried sewage sludge – DSS) were treated using selected oxidation processes (ozonation – O3, photolysis – UV, and photocatalysis – UV-TiO2). The decomposition of organic substances present in the tars was investigated by changing the absorbance (Abs), total organic carbon (TOC), and phenol index (PI). Tar solutions before and after treatment were also submitted to an ecotoxicological assessment. It was determined that the tars organic substances content depended on the type of biomass subjected to solar pyrolysis. The highest concentration of organics was denoted in the liquid products from the solar pyrolysis of the sewage sludge. The decomposition of organic substances took place in the process of photocatalysis and ozonation, with higher effectiveness of the latter. The organic compounds present in the solar pyrolysis tar depend on the biomass feedstock. After 60 min of photocatalysis (TiO2 dose 1500 mg/L), phenolic compounds from tars coming from the solar pyrolysis of waste straw and wood chips were completely removed. In turn, the reduction in Abs and TOC was 37 and 19% for WS and 41 and 28% for WC, respectively. Abs in tars from the solar pyrolysis of sewage sludge in the photocatalysis process did not change, and the reduction of TOC and PI was 8 and 86%, respectively. However, the toxicity of post-process solutions requires attention. Tar solutions from the solar pyrolysis of wood chips after the photocatalysis process were non-toxic against bacteria, but tar solutions coming from the solar pyrolysis of waste straw and sewage sludge were low-toxic and toxic. Additionally, tars from the solar pyrolysis of sewage sludge after the photocatalysis process were highly toxic to crustaceans.

Recent advances in sludge dewatering and drying technology

Sewage sludge is an inevitable by-product of biological wastewater treatment process and contains various toxic substances such as pathogens, heavy metals and organic contaminants, which may cause serious pollution risks without appropriate disposals. Dewatering and drying technology play significant roles in minimizing sludge volume, facilitating transportation, increasing calorific value and reducing the leachate production in landfill sites. Various new technologies are emerging and existing ones are always evolving because of sharp growth of sewage sludge in the last decade. This paper presents a comprehensive review on recent advances in related to dewatering and drying of sewage sludge. The influencing factors of sludge dewatering are addressed out firstly. And then the conditioning methods to improve sludge dewatering performance are summarized and compared in terms of applicable occasions, material consumption, energy and environmental impacts etc. The dewatering technology is classified into common, deep and high-dry dewatering based on the degree of moisture content, and the drying method is divided into convective drying, conduction drying, radiation drying and other new drying. The present dewatering and drying technologies are reviewed and compared in order to provide useful guidelines for sludge disposal. The future demands and opportunities for sludge dewatering and drying are pointed out from industrial perspective.

Parasitological Assessment of Sewage Sludge Samples for Potential Agricultural Reuse in Tunisia.

Wastewater sludge represents an important resource for reuse in agriculture. However, potentially harmful pathogens are a main threat in this context. Thus, the aim of this study was to examine the presence of helminth ova and protozoan cysts in dried sewage sludge samples collected from ten wastewater treatment plants (WWTPs) located in eight governorates in Tunisia. Based on morphological criteria, protozoan cysts of Giardia spp., Entamoeba histolytica/dispar/moshkovskii, and Entamoeba coli, were detected in all dried sludge composite samples (N = 116) from the investigated WWTPs. The mean concentration ranged from 1.4 to 10.7 cysts per 100 g dry matter (DM). The identified helminth eggs were Ascaris spp., Strongyles, Taeniid eggs, Hymenolepis nana, Enterobius vermicularis, and hookworm species. Ascaris spp. and Taeniid eggs were detected in 56.9 and 74.1% of analyzed samples, respectively. The presence of Trichuris spp., Hymenolepis diminuta, and Toxocara spp. eggs in dried sewage sludge samples was low (0.9, 1.7, and 2.6%, respectively). The mean concentration of helminth eggs during the three-year study was less than 1 egg/100 g DM. All examined dried sewage sludge sample contents were below the WHO (2006) and US EPA (2003) recommendations, and thus, the sludge can potentially be reused in agriculture.

Impact of acceleration of agricultural and industrial waste conditioning on thermal drying of sewage sludge.

Improving the dewatering performance of sludge is a necessary advancement for collaborative sludge disposal and energy-efficient utilization in power plants. Herein, the effects of temperature changes and the addition of drying accelerators derived from agricultural and industrial waste on the drying characteristics of sewage sludge (SS) were investigated from the perspectives of drying kinetics and micromorphology. According to the results, the drying time for sludge significantly showed a clear downward trend via medium-low temperature (160°C) thermal drying, which subsequently reduced the energy input substantially. When the drying temperature was 160°C, the ideal addition proportions of rice husk (RH), sludge ash (SA), and coal ash (CA) comprised 15%. The addition of SA prominently boosted the drying rate constant of the original sludge by 48%. Additionally, SEM images along with the spectral dimension obtained via fractal theory explicitly clearly demonstrated that SS + SA had more loose pore channels than other mixed samples. This provided a convenient approach to ensure the evaporation and migration of moisture and thereby shorten the drying time effectively. Consequently, the addition of sludge ash as a drying accelerator can promote the deep dewatering of sludge.

Greenhouse Assays with Lactuca sativa for Testing Sewage Sludge-Based Soil Amendments

Sustainable agriculture practices within the guidelines of nutrient recycling and the circular economy must be increasingly promoted. This work aims to evaluate the performance of dried sewage sludge (DSS), green liquor dregs mixed with sewage sludge (DSSA), raw sewage sludge, and commercial organic fertilizer control, using a short-term agronomic assessment with lettuce crop (Lactuca sativa) in greenhouse conditions. Different application rates based on the nitrogen content were tested for each soil amendment: 0, 85, 170, and 225 kg N/ha (treatments T0, T1, T2, and T3, respectively). DSS and DSSA resulted in fresh lettuce productivities 1.3 and 3.2 times higher in T3 than in T0, respectively. The ideal N content in lettuce leaves was reached for all materials and treatments, with the highest values obtained for DSS (2.88–3.33% from T1 to T3). Lettuce produced in soils amended with DSS and DSSA showed also ideal levels of Ca. Overall, the performance of sludge-based products was similar to commercial fertilizer, without impairing the nutritional balance of the crop and the soil.

Use of ballasted flocculation (BF) sludge for the manufacturing of lightweight aggregates

Ballasted flocculation (BF) is an efficient way to remove the turbidity from surface water. The objective of the present study is to optimize the ballast (magnetite), coagulant (poly aluminum chloride) concentration and pH for efficient turbidity removal from surface water. To do this, the sludge produced from an optimized dose of a BF treatment was utilized for the production of lightweight (LW) aggregates by combining it with hard clay and sewage sludge. The LW aggregates were formed by means of rapid sintering in the temperature range of 1000–1200 °C with an exposure time of 10 min. The physical properties of the LW aggregates, in this case the leaching of heavy metals, the bulk density and the microstructure, were investigated. The results indicated that corresponding ballast and coagulant concentrations of 0.75 g/L and 30 mg/L (poly aluminum chloride (PAC)) resulted in the maximum removal efficiency of ≈95%. Using a mixture of BF sludge (30 wt%), dry sewage sludge (20 wt%), and hard clay (50 wt%), aggregates with a density of around 1.0 g/cm3 could be produced. In addition, it was confirmed that the manufactured aggregate was environmentally stable as the elution of heavy metals was suppressed.

Varying Effects of Organic Waste Products on Yields of Market Garden Crops in a 4-Year Field Experiment under Tropical Conditions

Controlling organic and mineral fertilisation is a major concern in tropical environments. An experiment was conducted on an arenosol in the Dakar region, the main market gardening area of Senegal, to evaluate treatments commonly used by farmers. Seven treatments were repeated three times: A mineral fertilisation (MF) treatment based on N-P2O5-K2O (10-10-20), and three organic treatments at two doses (dried sewage sludge (SS), poultry litter (PL) and a digestate from an anaerobic digestion (AD) of cow manures). Each of the organic treatments were supplemented with a normal dose (1) and a double dose (2) of mineral N and K fertiliser. A lettuce, carrot and tomato rotation was grown in four campaigns (2016–2020) on all of the plots. Yields of all three crops in all of the organic treatments were statistically similar (p &gt; 0.05) to the MF in all four campaigns, except for the yield of the lettuce crop under treatment PL-2 in campaigns 2 and 3. The tomato yields were statistically similar under all of the organic treatments in all four campaigns. In contrast, the yields of the lettuce and carrot crops differed statistically from each other and under the different organic treatments in all four campaigns. The yields of all three crops differed in the campaigns with the fertilisation treatment. In each campaign, the yields of each crop were not correlated with the total amounts of N, P and K applied. These differences or similarities in yields are explained by the nature of the organic waste products, the accumulation of nutrients after several applications, the type of crop and interannual differences in temperature.

A comprehensive study of the high temperature pyrolysis of sewage sludge: kinetics, energy analysis and products formation

&lt;p&gt;This study evaluates the pyrolysis of sewage sludge until 960 °C using heating rates between 3 K/min and 12 K/min in a macro TG/EGA. Mass and energy balances and kinetic parameters are determined. Thermal decomposition is divided into a low temperature zone (until 550 °C to 590 °C), for decomposition of organic matter, and a high temperature zone, for decomposition of inorganic matter and secondary reactions of the residual organic matter. In dry basis at 570 °C solid, liquid and gaseous products amount to 69.2 wt.-%, 29.2 wt.-% and 1.6 wt.-%, respectively. An increment in the final temperature to 960 °C causes a successive decrease of the solid residue to 56.9 wt.-%. The solid product contains more than 80 wt.-% mineral matter with high amounts of valuable elements, such as Ca and P. An energy requirement of 2.18 MJ/kg of dry sewage sludge is calculated for the pyrolysis until 570 °C. At this temperature, 58.5 % of the energy entering the process is concentrated in the liquid product and 40.0 % in the solid. A suitable set of kinetic parameters is determined through a formal independent parallel reactions model with six-pseudo components, using a combination of isoconversional and fitting methods.&lt;/p&gt;&#x0D;

Two-stage gasification of dried sewage sludge: Effects of gasifying agent, bed material, gas cleaning system, and Ni-coated distributor on product gas quality

Dried sewage sludge gasification was conducted using a two–stage gasifier composed of a fluidized bed gasifier and tar–cracking reactor to produce a gas with low levels of tar, NH3, and H2S. In this work, the influence of the type of gasifying agent and bed material and the equivalence ratio on the product gas quality were investigated. Furthermore, the possibility of gasification without a hot filter and electrostatic precipitator, which are usually applied to remove impurities generated during gasification, was examined. Finally, the efficiency of a Ni–coated distributor for tar and NH3 removal was evaluated. Overall, steam/O2 gasification produced H2–rich (38–39 vol%) gases. Further, olivine reduced the tar and NH3 contents in the product gas obtained from steam/O2 gasification to 138 mg/Nm3 and 236 ppmv, respectively. A gas cleaning system without a hot filter and electrostatic precipitator produced a gas with only 8 mg/Nm3 of tar. Moreover, a Ni-coated distributor was found to be very effective in reducing the NH3 content to 60 ppmv. Dried sewage sludge gasification experiments in air were conducted four times for 4 h, producing gases with very low levels of tar (3–10 mg/Nm3) and NH3 (60–90 ppmv).

Formulation and evaluation of organo-mineral fertilizers based on sewage sludge optimized for maize and sunflower crops.

The depletion of natural resources, energy consumption and environmental issues relating to fertilizer production processes are driving a move towards a more sustainable use of resources and the recycling of nutrients. With regard to the fertilizer industry, this gives the opportunity to use the fertilizing potential of alternative raw materials. This paper evaluates the possibility of using dried sewage sludge in the manufacture of organo-mineral fertilizers. Fertilizers based on sewage sludge with an addition of poultry litter ash and mineral fertilizers were developed and characterized in the study. It was possible to produce multicomponent organo-mineral fertilizers with optimized compositions for maize and sunflower crops, characterized by total nutrient content over 20%. Moreover, they contained beneficial secondary nutrients and micronutrients originated from waste materials. The fertilizers were free of pathogens and fulfilled the requirements related to heavy metal content according to Polish legislation. The method of manufacturing organo-mineral fertilizers based on waste materials is a simple waste management solution offering organic matter and nutrient recycling in line with the circular economy and reducing reliance on imported raw materials.

Sewage Sludge - a Sustainable Material for the Production of Solid Recovered Fuel

The appropriate quality system of production control of pre-treated sewage sludge and its characterization needs to be established in order to provide confidence in its constant quality as a raw material in the circular economy. Waste to energy procedure with increased energy efficiency in utilization of its residues is gaining an increased recognition. To manage waste to energy procedure the pre-treated (dried) sludge must be continuously assessed in accordance with the CEN/TC 343 technical standards and the European Union (EU) initiative for circular economy. In evaluation of the dried sewage sludge as an alternative solid recovered fuel (SRF), three parameters are important – net calorific value (NCV), chlorine (Cl) and mercury (Hg) content. The statement of the authorized contractor on the quality of sewage sludge as a SRF with the Class code NCV 3 to 4; Cl 1; Hg 3 creates confidence in its stable quality for energy production in cement kilns, power plants and dedicated sludge mono-incinerators. The removal of Hg from municipal wastewater, constant quality control of the dried sewage sludge, and tracking the mass balance of Hg during incineration make it possible to prevent the circulation of this critical pollutant in the environment.

Impact of dry sewage sludge on characteristics of concrete

Nowadays, the accumulation of various waste products is increasing day by day. So there is a great need for their proper disposal, without harming the environment. Moreover, due to the limited availability of natural resources like fine aggregates. There is a need for alternative building materials. The study's primary goal was to find an alternative, effective disposal method of dry sewage sludge of wastewater treatment plants as a building material. The possibility of using dry sewage sludge in concrete was assessed in this study. Various properties, like workability, compressive strength, ultrasonic pulse velocity, split tensile strength, water absorption, and cost-benefit analysis were reported in the study. According to the study, utilizing 5% of dry sewage sludge as a fine aggregate is possible without having a significant negative influence on concrete characteristics. With the use of dry sewage sludge, the manufacturing cost of concrete can be reduced by1.63%.

Production of biochar from the combination of foaming drying and pyrolysis of sludge with the additive of Camellia oleifera shell biochar

In this study, a combination of foaming drying and pyrolysis of sewage sludge (SS) with the additive of Camellia oleifera shell biochar (COSC) process was performed to investigate the effects of process parameters on the foaming drying process, and the properties of the produced biochar. The physical and chemical properties of the products were analyzed and the produced biochar was characterized by FTIR, XPS, and XRD analyses. The produced bio-oil was analyzed by gas chromatography-mass spectrometer (GC–MS). Foamed sludge mixed with Camellia oleifera shell biochar (250−850 μm) (COSC-FS) has a higher drying efficiency. Compared with the dried SS, the dried foamed sludge (FS) has lower HHVs, C, H, N, O content, and higher ash content. The main component of bio-oil was nitrogen-containing aliphatic compounds. Though having a lower specific surface area than unfoaming pretreatment, the biochar obtained from the pyrolysis of foamed sludge mixed with Camellia oleifera shell biochar (COSC-FSC) still has a higher adsorption ability for Pb(II) due to co-precipitation. The addition of NaOH had no effect on the pH of solution from Pb(II) adsorption by COSC-FSC. The adsorption behavior of Pb(II) adsorbed onto the COSC-FSC can be well described by pseudo-second-order kinetic model and Langmuir isotherm model with the improved maximum adsorption capacity of 179.33 mg/g. This work provides a promising method for the disposal and the resource utilization of sludge.