scholarly journals Effects of the Combined Utilization of Ultrasonic/Hydrogen Peroxide on Excess Sludge Destruction

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 266
Author(s):  
Dehao Yuan ◽  
Xu Zhou ◽  
Wenbiao Jin ◽  
Wei Han ◽  
Huizhong Chi ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ultrasonic Treatment ◽  
Reduction Rate ◽  
Ammonia Nitrogen ◽  
Operating Conditions ◽  
Sludge Reduction ◽  
Excess Sludge ◽  
Nitrogen And Phosphorus ◽  
Sludge Destruction ◽  
Sludge Concentration

Excess sludge reduction has been a research hotspot for a long time. Ultrasonic treatment of excess sludge was an efficient and green pretreatment method, and also can be combined with the addition of oxidants. To improve the effect of ultrasound treatment on sludge destruction, hydrogen peroxide (H2O2) was added to examine the combined results in the current study. The effects of the ultrasound/hydrogen peroxide system on the release of sludge organic matter during the destruction process were studied. Single-factor experiments were carried out to determine the optimal operating conditions. With the initial pH of 11.0, H2O2 concentration of 0.5 mmol/L, initial sludge concentration of 17 g/L, and 15 min ultrasonic treatment, the maximum soluble chemical oxygen demand (ΔSCOD) in the sludge supernatant after destruction was achieved at 3662.78 ± 239.21 mg/L, with a disintegration degree of 28.61 ± 2.14%, sludge reduction rate of 19.47 ± 0.82%, and the change of mixture sludge concentration (ΔMLSS) of 3.31 ± 0.06 g/L. Meanwhile, the release of nitrogen and phosphorus were greatly improved. Under the optimal conditions, the release of total nitrogen (TN), ammonia nitrogen (NH3-N) and total phosphorus (TP) were 282.30 ± 24.06 mg/L, 25.68 ± 2.09 mg/L, and 105.69 ± 7.84 mg/L, respectively. The current work had provided solid evidence showing the addition of hydrogen peroxide can effectively strengthen the treatment effects of ultrasound on sludge destruction.

The discharged excess sludge treated by Oligochaeta

2005 ◽  
Vol 52 (10-11) ◽  
pp. 265-272 ◽  
Author(s):  
Y. Wei ◽  
J. Liu
Keyword(s):  
Activated Sludge ◽  
Inorganic Nitrogen ◽  
Nitrogen Concentration ◽  
Ammonia Nitrogen ◽  
Tubifex Tubifex ◽  
Sludge Reduction ◽  
Excess Sludge ◽  
Nitrogen And Phosphorus ◽  
Free Swimming ◽  
Activated Sludge System

To overcome unstable worm growth, a new worm-reactor was developed for oligochaete growth. The bench scale of this worm-reactor was used to treat the discharged excess sludge from a pilot activated sludge system, and experiments were carried out to investigate the sludge reduction induced by Oligochaeta. Due to difficult getting free-swimming worms such as Aeolosoma hemprichicii and Nais elinguis, Tubifex tubifex was thus selected and inoculated in Reactor 1 at the start-up phase except the control reactor (Reactor 2). Tubifex occurred in Reactor 1 throughout the operation period after its inoculation, and mainly attached on the carriers and aggregated on the bottom of the worm-reactor. Free-swimming worms such as Aeolosoma hemprichicii, Nais elinguis, and Aulophorus furcatus were found in both reactors since the 35th day. Microscopic investigation showed that these free-swimming worms naturally produced in the pilot activated sludge system, and entered into both reactors along the discharged sludge. Results clearly showed that the average sludge reduction in Reactor 1 was 59%, much higher than that in the control. The characteristics of sludge settling was improved by worm growth, but was not too much. High ammonia nitrogen concentration in influent sludge was toxic to worms, and then inhibited worm growth. Both the total inorganic nitrogen and phosphorus releases into effluent sludge were observed in Reactor 1, but such increases were not heavy.

Progress and Perspectives of Microfauna as a Powerful Method for Excess Sludge Reduction in Wastewater Treatment

2012 ◽  
Vol 446-449 ◽  
pp. 2824-2828 ◽  
Author(s):  
Li Min Zhao ◽  
Sen Wen
Keyword(s):  
Wastewater Treatment ◽  
Environmental Economic ◽  
Sewage Sludge ◽  
Operating Conditions ◽  
Sludge Reduction ◽  
Powerful Method ◽  
Excess Sludge ◽  
Excess Sludge Reduction

Disposal of sewage sludge by environmentally acceptable means is a serious problem, due to environmental, economic, social and legal factors. This paper presents an overview of the potential of the application of the microfauna, such as the aquatic worms and the earthworms in excess sludge reduction in wastewater treatment. Significant sludge reduction was achieved in the presence of the aquatic worms or the earthworms. Additionally, the effect of operating conditions on the excess sludge reduction by the aquatic worms and the earthworms are also presented.

Mechanism Analysis and Experimental Research on the Interception of Nitrogen and Phosphorus Pollutants by Gullies in Northern China

2011 ◽  
Vol 250-253 ◽  
pp. 3392-3396
Author(s):  
Yu Jia Song ◽  
Hui Qing Liu
Keyword(s):  
Total Phosphorus ◽  
Nitrate Nitrogen ◽  
Northern China ◽  
Careful Analysis ◽  
Ammonia Nitrogen ◽  
Mechanism Analysis ◽  
Nitrogen And Phosphorus ◽  
Urban Sewage ◽  
Control Section ◽  
Nitrogen Pollutants

The discharge of urban sewage and agricultural non-point source pollutants is the main reason causing eutrophication in gullies in most cities of northern China. Based on a careful analysis on the ecological structure and ecological characteristics of a gully, this article preliminarily studies the interception and degradation mechanisms of nitrogen pollutants by the gully. Meanwhile, to take gullies in Changchun as the object of the study, this article carries out an experiment on the interception effect of nitrogen pollutants by gullies. This experiment respectively establishes a control section in the upper and lower reaches of a gully, and takes water samples four times in each section from May to August to determine total nitrogen, total phosphorus, nitrate nitrogen, ammonia nitrogen and salinity. The result shows: the gully plays some role in the interception of pollutants; total phosphorus accounts for the largest interception in pollutants in the experimented gully section, with the relative interception rate of 27.46%, followed by ammonia nitrogen, with the interception rate of 21.80%, which is the result of the combined effects of aquatic plants, microorganisms and sediment in the gully.

scholarly journals Graphene-Modulated Removal Performance of Nitrogen and Phosphorus Pollutants in a Sequencing Batch Chlorella Reactor

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2181 ◽  
Author(s):  
Gonghan Xia ◽  
Wenlai Xu ◽  
Qinglin Fang ◽  
Zishen Mou ◽  
Zhicheng Pan
Keyword(s):  
Optical Microscopy ◽  
Sewage Treatment ◽  
Ammonia Nitrogen ◽  
Pollutant Removal ◽  
Plate Count ◽  
Nitrogen And Phosphorus ◽  
Removal Rates ◽  
Practical Support ◽  
Plate Count Method ◽  
The Impact

In this work, the influence of graphene on nitrogen and phosphorus in a batch Chlorella reactor was studied. The impact of graphene on the removal performance of Chlorella was investigated in a home-built sewage treatment system with seven identical sequencing batch Chlorella reactors with graphene contents of 0 mg/L (T1), 0.05 mg/L (T2), 0.1 mg/L (T3), 0.2 mg/L (T4), 0.4 mg/L (T5), 0.8 mg/L (T6) and 10 mg/L (T7). The influence of graphene concentration and reaction time on the pollutant removal performance was studied. The malondialdehyde (MDA) and total superoxide dismutase (SOD) concentrations in each reactor were measured, and optical microscopy and scanning electron microscopy (SEM) characterizations were performed to determine the related mechanism. The results show that after 168 h, the total nitrogen (TN), ammonia nitrogen (AN) and total phosphorus (TP) removal rates of reactors T1–T7 become stable, and the TN, AN and TP removal rates were gradually reduced with increasing graphene concentration. At 96 h, the concentrations of both MDA and SOD in T1–T7 gradually increased as the graphene concentration increased. In optical microscopy and SEM measurements, it was found that graphene was adsorbed on the surface of Chlorella, and entered Chlorella cells, deforming and reducing Chlorella. Through the blood plate count method, we estimated an average Chlorella reduction of 16%. According to the water quality and microscopic experiments, it can be concluded that the addition of graphene causes oxidative damage to microalgae and destruction of the Chlorella cell wall and cell membrane, inhibiting the nitrogen and phosphorus removal in Chlorella reactors. This study provides theoretical and practical support for the safe use of graphene.

scholarly journals Improved sludge dewaterability and hydrolysis performance after pretreatment with Fenton's reagent

2017 ◽  
Vol 77 (1) ◽  
pp. 204-210 ◽  
Author(s):  
Hongying Yuan ◽  
Yuping Yang ◽  
Jian Yuan ◽  
Yanning Wang ◽  
Yameng Song ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Fenton’S Reagent ◽  
Excess Sludge ◽  
Reaction Conditions ◽  
Fenton's Reagent ◽  
Soluble Polysaccharide ◽  
Soluble Chemical Oxygen Demand ◽  
Sludge Dewaterability

Abstract The dewaterability of excess sludge significantly improved upon pretreatment with Fenton's reagent in this study. After 0.9 g/L of Fe2+ and 5.0 g/L of H2O2 were added to the sludge, and reacted for 2 h at pH = 4, the specific resistance to filtration (SRF) of the excess sludge decreased from an initial value of 29.74 × 1012 m/kg to 6.49 × 1012 m/kg. The factors that affected this improvement in sludge dewaterability as evaluated by SRF reduction showed the following order: H2O2 > pH > Fe2+ > reaction time. Furthermore, the hydrolysis performance of the sludge under the optimal reaction conditions was investigated. The results indicated that the concentration of soluble chemical oxygen demand in the supernatant increased almost 14 times compared to raw sludge, and the contents of soluble protein and soluble polysaccharide were more than 8 and 17 times higher, respectively, than for the untreated situation. However, the amounts of ammonia nitrogen (NH4+-N) and phosphate (PO43−-P) released from the sludge showed different trends: NH4+-N increased by 200%, while PO43−-P decreased by 82%. The production of volatile fatty acids (VFAs) from the treated sludge showed that total VFAs increased by 66%, and iso-butylacetic acid was the dominant product among the total VFAs.

Evaluation of Sludge Reduction Mechanisms in ‘Sonolysis-Cryptic Growth’ Wastewater Treatment System

2015 ◽  
Vol 768 ◽  
pp. 108-115
Author(s):  
Pan Yue Zhang ◽  
Tian Wan ◽  
Guang Ming Zhang
Keyword(s):  
Wastewater Treatment ◽  
Organic Load ◽  
Sludge Reduction ◽  
Excess Sludge ◽  
Operation Condition ◽  
Reduction Mechanisms ◽  
Residual Sludge ◽  
Cryptic Growth ◽  
Load Increase

‘Sonication - cryptic growth’ technology can reduce 30-80% excess sludge in wastewater treatment systems. Various mechanisms contribute to the sludge reduction but the role of each one is unclear. This paper quantitatively studied the potential mechanisms in ‘sonication - cryptic growth’. The operation condition was: every day 20% sludge was sonicated under 1.2 Wml-1 for 15 min and then returned to the wastewater treatment reactor for cryptic growth. The results showed that under such conditions, ‘sonication - cryptic growth’ reduced the excess sludge by 57.3% and the effluent met the national discharge standard. Multiple mechanisms were involved in the process. Detailed analysis showed that the ‘lysis-cryptic growth’ mechanism was the most important one and accounted for 49.1% of sludge reduction. Biodegradation of residual sludge was the second important one and contributed 19.5%. Other potential mechanisms included the altered microbial community, longer sludge retention time, and accumulation of persistent materials. But organic load increase had virtually no impact.

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