Research on the stability of heavy metals (Cu, Zn) in excess sludge with the pretreatment of thermal hydrolysis

2015 ◽  
Vol 73 (4) ◽  
pp. 890-898 ◽  
Author(s):  
Huimin Wu ◽  
Meng Li ◽  
Lei Zhang ◽  
Chao Sheng
Keyword(s):  
Heavy Metals ◽  
Anaerobic Digestion ◽  
Chemical Speciation ◽  
Stable Form ◽  
Thermal Hydrolysis ◽  
Excess Sludge ◽  
The Stability ◽  
Cu And Zn

Thermal hydrolysis (TH) has been used to improve anaerobic digestion performance as well as the stability of heavy metals in sludge. Because the toxicity of heavy metals is closely related to both the concentration and the chemical speciation, more exhaustive studies on speciation distribution are urgently needed. This research aimed to investigate the effects of TH treatment (especially the time and temperature) on the concentration and stability of heavy metals in sludge, and to define the optimal TH conditions. The TH experiment indicated that the content of the stable form of Cu and Zn reached 83% and 47.4%, respectively, with TH at 210°C and 30 min. Compared with the raw sludge, the proportion of Cu and Zn increased by 11.88% and 7.3%, respectively. Results indicated that the heavy metals were combined with sludge in a more stable form with the pretreatment of TH, which improved the stability of heavy metals.

Minimisation of excess sludge production in a WWTP by coupling thermal hydrolysis and rapid anaerobic digestion

2005 ◽  
Vol 52 (10-11) ◽  
pp. 255-263 ◽  
Author(s):  
J. Chauzy ◽  
S. Graja ◽  
F. Gerardin ◽  
D. Crétenot ◽  
L. Patria ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Pilot Plant ◽  
Hydraulic Retention Time ◽  
Wastewater Treatment Plants ◽  
Control Line ◽  
Thermal Hydrolysis ◽  
Excess Sludge ◽  
Anaerobic Digesters ◽  
Sludge Production

In many cases, reducing sludge production could be the solution for wastewater treatment plants (WWTP) that here difficulty evacuating the residuals of wastewater treatment. The aim of this study was to test the possibility of minimising the excess sludge production by coupling a thermal hydrolysis stage and an anaerobic digestion with a very short HRT. The tests were carried out on a 2,500 p.e. pilot plant installed on a recycling loop between the clarifier and the actived sludge basin. The line equipped with the full scale pilot plant produced 38% TSS less than the control line during a 10 week period. Moreover, the rapid anaerobic digestion removed, on average, more than 50% of the total COD load with a hydraulic retention time (HRT) of 3 days. Lastly, the dryness of the remaining excess sludge, sanitised by the thermal hydrolysis, was more than 35% with an industrial centrifuge. This combination of thermal hydrolysis and rapid anaerobic digestion equally permits a significant gain of compactness compared to traditional anaerobic digesters.

Sewage Sludge Thermal Hydrolysis Process

2013 ◽  
Vol 827 ◽  
pp. 368-373
Author(s):  
Guang Li ◽  
He Ren ◽  
Jing Li ◽  
Xiang Kui Han ◽  
Lian Peng Wang
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Organic Acids ◽  
Temperature Rise ◽  
Suspended Solids ◽  
Concentration Change ◽  
Thermal Hydrolysis ◽  
Excess Sludge ◽  
Hydrolysis Process ◽  
Hydrolysis Temperature

In 110~190°C for 15~75min excess sludge thermal hydrolysis test, investigated the dissolution rate of the volatile suspended solids, Sludge SCOD, TCOD concentration change in composition of organic acids in the supernatant, and analysis the improvement of the anaerobic digestion performance. The results show that, with the increase of thermal hydrolysis temperature and extension of time, sludge supernatant on SCOD, VFA rising. At 190 °C, 75min conditions, SCOD, VFA reached the maximum 6674mg / L2630mg/ L; Sludge organic solids dissolved and the release of COD, etc. mainly in the first 45 min to complete, little change after 45min. When thermal hydrolysis temperature between 90~170°C, anaerobic digestion performance increase with temperature rise, When the temperature is higher than 170 °C, the sludge anaerobic digestion performance begins to decline.

Combination of High Pressure and Thermal Hydrolysis Pretreatment Effect on Sludge

2013 ◽  
Vol 838-841 ◽  
pp. 18-22
Author(s):  
Guang Li ◽  
Xiao Xia Jiao ◽  
Jing Li ◽  
Xiang Kui Han ◽  
Lian Peng Wang
Keyword(s):  
High Pressure ◽  
Anaerobic Digestion ◽  
Organic Acids ◽  
Suspended Solid ◽  
Volatile Suspended Solid ◽  
Thermal Hydrolysis ◽  
Supernatant Fluid ◽  
Excess Sludge ◽  
Characteristics Analysis ◽  
Hydrolysis Temperature

In 110-190°C for 15-75 min of excess sludge thermal hydrolysis experiment, inspected the volatile suspended solid dissolution rate, the concentration of sludge SCOD, TCOD, components of organic acids in the supernatant fluid changes,such as sewage thermal hydrolysis characteristics, analysis the effect to improve the performance of sludge anaerobic digestion. The results show that with the increase of thermal hydrolysis temperature and time, SCOD and VFA in the sludge supernatant on rising. Under the condition of 190°C,75min, SCOD and VFA reached a maximum of 6674 mg/L,2630 mg/L; Release of sludge organic dissolved solids,COD and other major completed in the first 45 min,after 45 min changed little; Thermal hydrolysis temperature was between 90~170°C,sludge anaerobic digestion performance increases with temperature,when the temperature was higher than 170°C,sludge anaerobic digestion performance began to decline.

Preparation, Stabilization and Some Properties of Purified Human Plasmin*

1964 ◽  
Vol 11 (01) ◽  
pp. 075-084 ◽  
Author(s):  
Daniel L Kline ◽  
Jacob B Fishman ◽  
Keyword(s):  
Plasminogen Activator ◽  
Stable Form ◽  
Neutral Ph ◽  
The Stability ◽  
And Storage

Summary1. Lysine increased the solubility, decreased the SK requirement and increased the stability of plasmin prepared from purified plasminogen by SK activation.2. A procedure is presented for the rapid and quantitative conversion of plasminogen to plasmin and storage of the plasmin in stable form at neutral pH as a lyophilized powder.3. Approximately 10% for the plasminogen molecule was split off during its activation. No carbohydrate was lost.4. The plasmin isolated was homogeneous in the ultracentrifuge at pH 2.5 and was quantitatively convertible to plasminogen activator by the addition of SK.

Assessment of heavy metals in tobacco of cigarettes commonly sold in Ethiopia

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Heavy Metals ◽  
Trace Metals ◽  
Atomic Absorption Spectrophotometry ◽  
Epidemiological Studies ◽  
Cigarette Tobacco ◽  
Absorption Spectrophotometry ◽  
Wet Digestion ◽  
Metal Contents ◽  
Cu And Zn ◽  
Significant Flux

A significant flux of heavy metals, among other toxins, reaches the lungs through smoking. This study reports Cd, Pb, Cu and Zn contents in tobacco of 11 brands of cigarette commonly sold in Ethiopia. The heavy metals were determined by atomic absorption spectrophotometry after wet digestion of cigarette tobacco using HNO3 and H2O2. The concentration of trace metals in the cigarettes ranged (mean) (μg/g), Cd: 1.3−7.6 (2.48±0.32), Pb: 0.50−12.50 (6.24±2.2), Cu: 2.89−25.35 (13.70±4.12) and Zn: 24.40−62.55 (36.22±7.50) while Ni was not detected in all the eleven brands of cigarettes. Comparable levels of trace metals were obtained in the tobacco of both imported and Ethiopian cigarettes. The average trace metal contents of cigarettes available in Ethiopia were Cd 1.82±0.39, Pb 4.23±0.97, Cu 10.2±3.1 and Zn 28.2±7.8 μg/cigarette and a person who smokes 20 cigarettes per day is estimated to increase his/her daily Cd, Pb, Cu and Zn retention by approximately 0.036, 0.085, 0.204, 0.564 mg/day, respectively. The results indicate that smoking and exposure to cigarette smoke is a serious problem to be taken into account when carrying out epidemiological studies on human exposure to trace metals.

HEAVY METALS IN WATER, SEDIMENTS AND MARINE FISHES FROM BULGARIAN BLACK SEA

2017 ◽  
Author(s):  
Katya Peycheva ◽  
Katya Peycheva ◽  
Mona Stancheva ◽  
Mona Stancheva ◽  
Stanislava Georgieva ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Black Sea ◽  
Fish Species ◽  
Distribution Patterns ◽  
Marine Fishes ◽  
Marine Water ◽  
Mean Values ◽  
Sprattus Sprattus ◽  
Cu And Zn

In this study, the ecosystem marine water-sediment-biota was investigated and the pollution was assessed. The concentrations of eight elements were determined in marine water, sediments and four fish species collected from Black Sea (Varna), Bulgaria during 2013. Marine water recorded the highest concentrations of Zn (15-22 μg/L), As (1.1–1.2 μg/L) and Pb (0.7-0.8 μg/L) while Zn (31-52 μg/g), Pb (21-29 μg/g) and Cu (20-34 μg/g) and show the highest concentrations in sediments. Water and sediments showed similar spatial distribution patterns for the highest mean values of the different metals. In the analysed fish species, the highest concentration of the metals Cu and Zn were found in Trachurus Mediterrneus (0.42 mg/kg w.w) and in Sprattus Sprattus (12.7 mg/kg w.w), respectively while the heavy metals As and Hg were found with maximum values in Pseta Maxima (3.99 mg/kg w.w and 0.08 mg/kg w.w respectively). The results from this study were compared with our data for a previous period (2004-2006) and they show decrease in the levels of heavy metal.

Stability of Ceramic Glazes Obtained by Valorification of Anorganic Pigments Extracted from Electroplating Sludge

2018 ◽  
Vol 69 (3) ◽  
pp. 571-574
Author(s):  
Mihaela Andreea Mitiu ◽  
Maria Iuliana Marcus ◽  
Maria Vlad ◽  
Cristina Mihaela Balaceanu
Keyword(s):  
Heavy Metals ◽  
Leaching Tests ◽  
Ceramic Tiles ◽  
Research Activity ◽  
Limit Values ◽  
Leaching Potential ◽  
International Standard ◽  
Ceramic Samples ◽  
Electroplating Sludge ◽  
The Stability

This paper presents the results of the research activity in order to etablish the stability and leaching potential of ceramic tiles which have been developed using glazes colored with pigments obtained by the extraction of chromium and iron metals from electroplating sludge. All these ceramic tiles contain various amounts of heavy metals in their glazes due to the pigments composition. The ceramic samples have been subjected to leaching tests in order to detect if various elements of relevance such as chromium, lead, cadmium, zinc or iron migrated to any great extent into test solutions. Leaching tests have been performed following the international standard SR ISO 10545-15 method for specific metals leaching into 4% acetic acid solutions at 220C after a 24h period and the international standard SR EN 12457/1-4 method with distilled water as leaching agent at LSR of 10 l/kg, for 24h period. Amounts of heavy metals have been negligible or non-detectable (iron) in the leaching solutions, being well below the limit values established by the legislation in force.

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