Disintegration Of Excess Sludge Research Articles

Excess Sludge Disintegration by Discharge Plasma Coupled with Thiosulfate

Surplus sludge disposal and treatment are major issues in wastewater treatment plants. Discharge plasma oxidation is an effective approach for sludge dewatering and digestion. In this study, excess sludge disintegration by non-thermal discharge plasma coupled with thiosulfate (TSA) was investigated. After 20 min of the single discharge plasma treatment, the soluble chemical oxygen demand (SCOD) increased to 404.93 mg L−1, and it climbed even more to 549.08 mg L−1 after adding 15 mmol L−1 of TSA. The water content of the filter cake also reduced even more in the presence of TSA. There was an appropriate dosage of TSA available. In the discharge plasma coupled with TSA system, reactive oxygen species (·OH and O2−) were generated and had significant involvement in the disintegration of the sludge. The addition of TSA enhanced the production of OH. These reactive oxygen species decomposed the floc structures and facilitated the transformation of organic compounds, resulting in a decrease in the average size of the sludge aggregates. The ratio of soluble extracellular polymer substances (S-EPS) was enhanced, while the ratio of the tightly bound fraction was reduced after the treatment. Thus, discharge plasma coupled with TSA promoted microbial cell lysis and facilitated the release of intracellular organic matter and bound water, ultimately enhancing the sludge’s dewaterability.

Biogas Production from Excess Sludge Oxidized with Peracetic Acid (PAA)

Human functioning related to living and economic activity involves generating an increasing amount of sewage and sludge, which needs to be subjected to advanced processes of treatment, neutralization, and management. The deterioration in the susceptibility of excess sludge to biochemical decomposition observed under anaerobic conditions leads to the development and application of highly effective methods of wastewater treatment based on the removal of biogenic compounds using activated sludge, with a high degree of sludge thickening obtained in mechanical facilities. The concentration of volatile fatty acids, being an important intermediate product of anaerobic stabilization, directly determines biogas production efficiency. This study aimed to determine the effect of chemical disintegration with peracetic acid on biogas production efficiency using methane fermentation of pretreated sludge. Intensification of the hydrolysis phase is an important determinant of the efficiency of biochemical sludge decomposition under anaerobic conditions. The association of excess sludge oxidation, initiated by peracetic acid with biological hydrolysis, which is the first phase of methane fermentation, led to an increase in sludge digestion degree and biogas production efficiency. The compound of STERIDIAL W-10, which is an aqueous solution of 10% peracetic acid, 10% acetic acid, and 8% hydrogen peroxide, was used. The disintegration of excess sludge with a reactant dose of 3.0 mL of STERIDIAL W-10/L yielded a specific biogas production of 0.52 L/g VSS and a 74% degree of sludge digestion.

Mechanism Investigation of Excess Sludge Disintegration by Stirred Ball Mill—Utilized Transmission Electron Microscope Observation and Peptidoglycan Concentration Determination

Mechanism Investigation of Excess Sludge Disintegration by Stirred Ball Mill—Utilized Transmission Electron Microscope Observation and Peptidoglycan Concentration Determination

Excess sludge disintegration by discharge plasma oxidation: Efficiency and underlying mechanisms

A huge amount of excess sludge is inevitably produced in wastewater treatment, and it is becoming more and more urgent to realize efficient sludge reduction. Discharge plasma oxidation was used to efficiently disintegrate excess sludge for sludge reduction in this study. Approximately 18.22% sludge disintegration and 27.8% reduction of total suspended solids (TSS) were achieved by discharge plasma treatment. The water content of the filter cake decreased from 81.9% to 76.0% and the bound water content decreased from 2.66 g/g dry solid to 0.73 g/g dry solid after treatment. The large quantities of reactive oxygen species (ROS) generated by discharge plasma played important roles in sludge disintegration by destroying flocs and promoting the transformation of organic substances. Concurrent cell lysis induced by ROS oxidation released intracellular organics and water into the liquid phase. The fraction of soluble extracellular polymer substances (S-EPS) was enhanced from 16.10% to 58.51%, whereas the tightly bound fraction was reduced from 70.62% to 28.91%. Migration and decomposition of EPS were the main processes for EPS changing at a low oxidation capacity, whereas cell lysis became important at a high oxidation capacity. In summary, the plasma treatment effectively improved sludge disintegration.

The disintegration of excess sludge enhanced by short-term interaction with potassium ferrate: Characteristics and mechanism

The increasing amount of excess sludge (ES) has become a heavy burden for biological wastewater treatment, and the function of potassium ferrate (PF) in ES treatment as a strong oxidizing reagent has received increasing attention. This study comprehensively investigated the contribution of different dosages of PF on sludge disintegration in a short time interaction with sludge, from the perspective of the rheological properties, adhesion ability, and microbial mortality rate of sludge. The results of electrochemical impedance spectroscopy found that the adhesion ability of sludge could greatly decrease to 6.9–30% of the initial one by PF treatment, and the results of the rotational rheometer revealed that the cross-linked structure of extracellular polymeric substances could be destructed by the oxidation characteristics of PF (ES/PF<15:3), resulting in the transformation of the sludge from gel to sol structure. Moreover, with the increasing dosage of PF (ES/PF<60:1), the microbial mortality rate in sludge could increase rapidly from an initial 17.3 to 50.4%, and as a result of the above reason, large amounts of biomacromolecules and phosphate were released into the liquid phase. These results concluded that PF could preferentially deconstruct the EPS structure in sludge, and then the excess PF could damage the cell membrane, which results in the release of intracellular materials, and eventually, ES was totally disintegrated. This study provided an investigation to understand the function of PF in the sludge disintegration and a reference for the application of PF in a mass reduction of sludge in a short time.

Effect of physical and chemical disintegration of excess sludge on the suscebility to biodegradation

Effect of physical and chemical disintegration of excess sludge on the suscebility to biodegradation

Effect of Thermal and Alkaline Disintegration of Excess Sludge on Biodegradation

Effect of Thermal and Alkaline Disintegration of Excess Sludge on Biodegradation

Biogas Generation from Sonicated Excess Sludge

The article presents an analysis of the possibilities of biogas production in the process of methane fermentation of sonicated excess sludge. The greater the percentage of methane in biogas, the higher its calorific value. In order to increase the intensity of biogas production containing approximately 70% of methane, sewage sludge is disintegrated. In particular, excess sludge formed as a result of advanced wastewater treatment by the activated sludge method shows low biodegradability. The study aim was to examine the effect of the ultrasonic field disintegration of excess sludge on biogas production. As a result of subjecting the sludge to disintegration by ultrasonic field, there was an increase in the digestion degree of sewage sludge. In the methane fermentation process of modified sludge, an increase of the biogas yield was noted, which confirmed the supportive action of ultrasonic field on the excess sludge biodegradation. In the case of disintegration of excess sludge by ultrasonic field, for the ultrasonic field intensity value of 4.3 W cm−2 and a sonication time equal to 300 s, the highest values of soluble chemical oxygen demand (SCOD), total organic carbon (TOC), and volatile fatty acids (VFAs) concentrations were obtained. In the process of conventional methane fermentation, biogas yield value was 0.303 L g VSS−1, while in the process of methane fermentation of sonicated excess sludge, the value 0.645 L g VSS−1.

Mechanism of Thermal Effect of Ultrasonic Cavitation on Excess Sludge Disintegration

Mechanism of Thermal Effect of Ultrasonic Cavitation on Excess Sludge Disintegration

Experimental Study on Disintegration of Excess Sludge by Explosive Shock Wave

Experimental Study on Disintegration of Excess Sludge by Explosive Shock Wave

Carbon source recovery from excess sludge by mechanical disintegration for biological denitrification.

The goal of the study was to evaluate the possibility of carbon source recovery from excess sludge by mechanical disintegration for biological denitrification. The total efficiency of denitrification, unit demand for organic compounds for denitrification, unit volume of disintegrated sludge and unit cost of nitrogen removal as a function of energy density used for excess sludge disintegration (70, 140 and 210 kJ/L) were analyzed. In the study a full-scale disc disintegrator was used (motor power: 30 kWh, motor speed: 2,950 rpm). It was shown that the amounts of organic compounds released from the activated sludge flocs at all tested levels of energy density are high enough to be used to intensify the removal of nitrogen compounds from wastewater. It was also documented that the energy density provided during process of disintegration was an important factor determining the characteristics of organic compounds obtained under the disintegration for their use in order to intensify the process of denitrification. The highest value of total efficiency of denitrification (50.5 ± 3.1 mg N/L) was obtained for carbon source recovery from excess sludge at 70 kJ/L, but the lowest unit cost of nitrogen removal occurred for 140 kJ/L (0.0019 ± 0.0011 EUR/g N).

The effects of mechanical sludge disintegration to enhance full-scale anaerobic digestion of municipal sludge

The main goal of the study was to evaluate the effects of mechanical sludge disintegration in enhancing full-scale anaerobic digestion of municipal sludge. Batch disintegration tests and lab dewatering tests were performed to determine the release of organic compounds and to assess the impact of disintegration of excess sludge before the fermentation process of mixed sludge on the dewaterability of post-fermented sludge, respectively. In the study, a disc disintegrator driven by a motor with a power of 30 kW, revolutions n = 2950 rpm, was used. It was shown that increased amounts of organic compounds were released from the sludge along with an increase in energy consumed in the disintegration. A part of the organic compounds were volatile fatty acids (VFAs). The highest share of VFAs in the released organic compounds (COD:VFA in the range of 6.6 ÷ 8.2) was obtained by performing disintegration at an energy density of 140 kJ/L. It was also documented that the introduction of excess sludge disintegration prior to the fermentation tank resulted in a significant increase in biogas production (by an average of 33.9%) and in an increase in volatile total solids reduction in the fermented sludge (by an average of 22.7%). Such a surplus of produced biogas would allow to produce ca. 1600 kWh/d net electricity and 7.5 GJ/d (2080 kWh/d) of heat. Moreover, it was documented that the share of disintegrated waste activated sludge in the mixed sludge subjected to the fermentation process could favourably influence the efficiency of post-fermented sludge dewatering.

Impact of the excess sludge modification with selected chemical reagents on the increase of dissolved organic substances concentration compounds transformations in activated sludge

Submission of excess sludge initial disintegration process significantly affects the efficiency of anaerobic stabilization process. Expression of increasing the concentration of organic matter in dissolved form is to increase sludge disintegration. As a result of chemical modification is an increase of the chemical oxygen demand and the concentration of volatile fatty acids. The aim of this study was to determine the impact of the disintegration process with selected chemical reagents to increase the concentration of organic substances in dissolved form. The process of chemical disintegration of excess sludge was treated using the following reagents: Mg(OH)2, Ca(OH)2, HCl, H2SO4, H2O2. The modification was carried out at ambient temperature for 2, 6 and 24h. During sludge disintegration it was noticed the growth of indicators values that confirmed the susceptibility of prepared sludge to biodegradation.

Intensification of anaerobic digestion efficiency with use of mechanical excess sludge disintegration in the context of increased energy production in wastewater treatment plants

The main goal of the study was to evaluate the effects of mechanical sludge disintegration for enhancing full scale anaerobic digestion of municipal sludge. Batch disintegration tests and lab dewatering tests were also performed aiming at determining the release of organic compounds and assessing the impact of disintegration of excess sludge before the fermentation process of mixed sludge on the dewaterability of post-fermented sludge, respectively. In the study a disc disintegrator driven by a motor with a power of 30 kW, revolutions n = 2950 rpm has been used. It was shown that with increase of energy consumed in the disintegration, the increased amounts of organic compounds were released from the sludge. It was also documented that the introduction of the excess sludge disintegration prior to fermentation tank, resulted in a significant increase in biogas production (by an average of 33.9%) and in increase in volatile total solids reduction in the fermented sludge (by an average of 22.7%). Moreover, the obtained results indicate the possibility of obtaining a higher degree of sludge dewatering, which was subjected to anaerobic stabilization with using disintegrated excess sludge.

Continuous reactor with anaerobic micro-organism to disintegrate excess sludge

Secondary pollution caused by excess sludge generated by sewage treatment continues to elicit an increasing amount of concern. To reduce the discharge of excess sludge in the process of sewage treatment, a continuous reactor with anaerobic micro-organism was designed and utilized to disintegrate excess sludge. After disintegrating for 360 h in this reactor, the volume of which was 4 L, the disintegration efficiency of excess sludge reached 50%. When the hydraulic retention time was 3 d, the concentrations of COD, -N, TP, protein, and polysaccharide increased from 72 mg L−1, 0.04 mg L−1, 0.005 mg L−1, 42.94 mg L−1 and 22.69 μg L−1 (0 h) to 3103 mg L−1, 3.11 mg L−1, 3.88 mg L−1, 37.32 mg L−1, and 83.78 μg L−1 (360 h), respectively. When the hydraulic retention time was 4 d, the concentrations of COD, -N, TP, protein, and polysaccharide were all higher than that when the hydraulic retention time was 3 d. All these indexes rose with the anaerobic time, and rose with the increase in hydraulic retention time. Results showed that the continuous reactor with anaerobic micro-organism has a good effect on excess sludge disintegration.

A Novel Rotating Disk System for Disintegration of Excess Sludge

Conventional activated sludge treatment process has been widely employed to deal with a variety of municipal and industrial waste water, but the production of sludge by this method is considerable. It is urgent to find an appropriate method which can solve this problem. Shear force produced by rotating disk system (a cell lysis system) was employed to break cell wall of sludge microorganism in order to release intracellular materials which can be reused as nutrient materials for metabolism of other sludge microorganisms in this study. Special feature on surfaces of disks had been proved to be a novel improvement which can improve disintegration effect apparently. Ultrasonic system can further promote minimization of excess sludge after treatment by rotating disk system in shorter time.

The impact of excess sludge disintegration on the changes of total organic carbon value

The impact of excess sludge disintegration on the changes of total organic carbon value

Disintegration of excess sludge enhanced by a combined treatment of gamma irradiation and modified coal fly ash

Abstract In order to improve the disintegration performance and accelerate the disintegration rate of excess sludge, the individual and combined influences of γ-ray irradiation and modified coal fly ash treatment on the disintegration of excess sludge were investigated based on physicochemical properties of excess sludge. The changes in constituents of excess sludge were examined by means of UV/vis spectra and SEM images. The results showed that the disintegration performance of excess sludge was effectively improved by gamma ray irradiation in the presence of modified coal fly ash. A new band from 250 nm to 290 nm appeared on all irradiated sludge samples. The SEM images illustrated the cells surfaces of the sludge by the combined treatment were disfigured. The SCOD, soluble carbohydrate and protein from sludge supernatant increased obviously with increasing modified CFA dosage from 0 to 0.2 g ml −1 and dose from 0 to 10 kGy. The sludge SRF and filter cake moisture declined significantly, and the filtration speed was faster. In conclusion, γ-ray irradiation-modified coal fly ash pretreatment is an effective method to disintegrate excess sludge.

Use of anaerobic hydrolysis pretreatment to enhance ultrasonic disintegration of excess sludge.

To improve the excess sludge disintegration efficiency, reduce the sludge disintegration cost, and increase sludge biodegradability, a combined pretreatment of anaerobic hydrolysis (AH) and ultrasonic treatment (UT) was proposed for excess sludge. Results showed that AH had an advantage in dissolving flocs, modifying sludge characteristics, and reducing the difficulty of sludge disintegration, whereas UT was advantageous in damaging cell walls, releasing intracellular substances, and decomposing macromolecular material. The combined AH-UT process was an efficient method for excess sludge pretreatment. The optimized solution involved AH for 3 days, followed by UT for 10 min. After treatment, chemical oxygen demand, protein, and peptidoglycan concentrations reached 3,949.5 mg O2/L, 752.5 mg/L and 619.1 mg/L, respectively. This work has great significance for further engineering applications, namely, reducing energy consumption, increasing the sludge disintegration rate, and improving the biochemical properties of sludge.

Animal Feeds Extracted from Excess Sludge by Enzyme, Acid and Base Hydrolysis Processes

Eighteen polycyclic aromatic hydrocarbons (PAHs) and crude proteins were recovered by the disintegration of excess sludge (ES) through enzyme hydrolyzed process (EHP), acid hydrolyzed process (AHP) and base hydrolyzed process (BHP) followed by isoelectric precipitation, centrifugation and freeze-drying. The BHP was observed to have the highest total concentrations of PAHs in the crude proteins as compared to AHP and EHP, following: EHP (213.7 ng/g) Zn > Mn > Cu > Pb > Ni > Cr > As > Hg > Cd in the ES samples before treatment. Except Zn, all the metals were in good agreement with the prescribed limits as defined by legal standard. Moreover, the concentration of all metal ions was found to be less or negligible in the EHP recovered proteins as compared to that in the BHP and AHP. The acu...