Sewage Sludge Melting Process: Preliminary System Design and Full-Scale Plant Study

1990 ◽  
Vol 22 (12) ◽  
pp. 329-338 ◽  
Author(s):  
S. Sakai ◽  
M. Hiraoka ◽  
N. Takeda ◽  
T. Tsunemi
Keyword(s):  
Sewage Sludge ◽  
Treatment Cost ◽  
Solid Phase ◽  
Construction Materials ◽  
Melting Process ◽  
Relative Energy ◽  
Full Scale ◽  
Sludge Treatment ◽  
Under Construction ◽  
Ash Disposal

A sewage sludge melting process has been developed and some full-scale planls have been installed or are now under construction in Japan. Sludge melting process has its main advantages in that most sorts of hazardous materials, such as heavy metals, are tightly fixed in solid phase and the slag produced by this process can be used as construction materials. This article analyzes sludge treatment and disposal costs of the popular sludge treatment alternatives with emphasis on thermal processes, especially the sludge melting process. From preliminary system designs on a common design basis, relative energy requirements and total treatment & disposal costs were compared. As a result of cost analysis in terms of the annual treatment cost, it was revealed that the lime conditioning systems cost some 50% more than the polymer conditioning, that in a comparison between the incineration and the melting systems the treatment cost differed when the difference in energy cost was significant, and that in the anaerobic digestion systems the superiority in energy balance did not contribute to treatment cost reduction. Even if as one of the cost conditions to introduce the melting system in place of the incineration system, the ash disposal price is set as low as 5,000 yen/t, the coke melting system is still advantageous in the lime conditioning. Further, it turned out that in the polymer conditioning systems it was possible to establish cost conditions to introduce the melting system when the incinerated ash disposal price, the melting process coke ratio and the coke price took certain values.

Sludge Melting Process with Hazardous Asbestos Wastes

1991 ◽  
Vol 23 (10-12) ◽  
pp. 2029-2037 ◽  
Author(s):  
S. Sakai ◽  
H. Takatsuki ◽  
M. Hiraoka ◽  
T. Tsunemi
Keyword(s):  
Sewage Sludge ◽  
Construction Materials ◽  
High Strength ◽  
Melting Process ◽  
Melting Behavior ◽  
X Ray Diffraction ◽  
Asbestos Cement ◽  
Plant Experiment ◽  
By Products ◽  
Temperature Melting

Sewage sludge melting has been developed and operated in full-scale plants for sludge processing and utilization of the by-products as construction materials. Hazardous asbestos wastes should be disposed of properly so not to lead to environmental pollution. The co-melting process for sewage sludge and asbestos wastes is discussed based on the basic melting behavior of asbestos and the laboratory plant experiment. Microscopic observation and X-ray diffraction analysis showed that asbestos forms could be changed physically and chemically by the high temperature melting. The disappearance of asbestos fibrous forms and chemical changes of its composition in the melted slag are not always concluded to be non-toxic, but considering that the melted slag is a rock-like material with high strength, the melting is acceptable as a method of hazardous asbestos waste disposal. Laboratory scale experiments have been conducted on co-melting disposal of sprayed-on chrysotile asbestos waste and a mixture of lime-added and polymer-added sewage sludge. It was possible to maintain the temperatures around 1600 °C and to discharge slag smoothly. It is also expected that asbestos cement wastes will contribute to the adjustment materials of basicity (CaO/SiO2) in the polymer-added sludge melting.

The behavior of ash components in the sludge melting process

1994 ◽  
Vol 30 (8) ◽  
pp. 197-207 ◽  
Author(s):  
Tunekazu Fukui ◽  
Tadahiro Murakami ◽  
Muneharu Ichikawa
Keyword(s):  
Sewage Sludge ◽  
Weight Reduction ◽  
Fine Particle ◽  
Construction Materials ◽  
Reduction Rate ◽  
Melting Furnace ◽  
Melting Process ◽  
Gas Treatment ◽  
Treatment Facilities ◽  
Heating Up

The Coke-bed sludge melting process is used for incinerating sewage sludge and producing slag that is recycled as construction materials. The behavior of ash exiting the melting furnace was examined. Heating tests were carried out with different kinds of sludge. Heating from 600°C to 1200°C, weight reduction of around 30% was measured, but reduction rate was due to the kind of sludge. Weight reduction was big when heating up to 815°C, and reduction at a temperature over 815°C was due to the type of sludge. Main materials causing weight reduction were unburnt carbon (C) and some other elements like sulfur (S), chlorine (Cl), some metals like sodium (Na), potassium (K) and oxygen (O) released from some kinds of oxides. Even though very small quantity, zinc (Zn) and lead (Pb) were also vaporized. Some of these vaporized substances precipitate and produce fine particle dust at the low-temperature section of gas treatment facilities. Washing harmless salts out from the dust then recycling the dewatered dust in the melting furnace was found to be effective in maximizing slag recovery and reducing the precipitator load.

Sludge treatment by ozonation Ð evaluation of full-scale results

2004 ◽  
Vol 49 (4) ◽  
pp. 247-253 ◽  
Author(s):  
M. Sievers ◽  
A. Ried ◽  
R. Koll
Keyword(s):  
Sewage Sludge ◽  
Suspended Solids ◽  
Full Scale ◽  
Mass Reduction ◽  
Sludge Treatment ◽  
Treatment Processes ◽  
Reduction Methods ◽  
Activated Sludge Processes ◽  
Chemical Sludge ◽  
Suitable Process

Ozonation of industrial and sewage sludge is a suitable process for minimizing the sludge production of activated sludge processes. The ozonation has the advantage for complete oxidation of volatile suspended solids (VSS) of combining partial sludge oxidation with subsequent biological oxidation. This paper describes the evaluation of two full-scale sewage sludge ozonation investigations for subsequent aerobic stabilisation as well as for subsequent anaerobic stabilisation compared to different sludge treatment processes. For both the anaerobic and aerobic application, sludge liquefying by release of 110 and 160 mg COD per g total suspended solids (TSS) has been reached at specific ozone consumption of 0.03 and 0.06 kg O3 per kg TSS, respectively. The subsequent biological treatment has reached a mass reduction of 20-35% for the aerobic and 19% for the anaerobic stabilisation. For both applications the specific ozone consumption was about 0.05 kg O3 per kg TSS to be treated. A comparison with mechanical and thermo-chemical sludge mass reduction methods shows that the mass reduction potential of ozonation is presently higher. Even though costs for sludge ozonation are higher compared to other methods, the optimisation potential for cost reduction of sludge ozonation is obvious from the results presented in this paper.

Production of fuels on the basis of sewage sludge through conditioning using high calorific value fractions

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Karl-Georg Schmelz ◽  
Anja Reipa ◽  
Hartmut Meyer
Keyword(s):  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Calorific Value ◽  
Fluidised Bed ◽  
Sludge Treatment ◽  
Heating Value ◽  
Fine Coal ◽  
Used Cars ◽  
Plastic Components

Emschergenossenschaft and Lippeverband operate 59 wastewater treatment plants which produce approx. 100,000 Mg TS of sewage sludge each year. Using sludge pressure pipelines, about 60 % of this sludge are transported to the central sludge treatment plant in Bottrop. The digested sludges are conditioned using fine coal and polymers and are dewatered using membrane filters. By adding coal, the heating value of the sludge is raised which enables autothermal combustion of the dewatered sludges in fluidised bed furnaces at the central sludge treatment plant. In order to replace coal, a fossil fuel, as conditioning agent, experiments were conducted using alternative materials with high heating values. The addition of shredder fluff agglomerates proved to be particularly successful. Shredder fluff agglomerates are a residue from the recycling of used cars and are generated in a multistage process (e.g. Volkswagen-SiCon Process) by separating the light shredder fraction (plastic components etc.) from the total shredder fluff. The fibrous material is outstandingly suitable for improving the dewaterability and for sufficiently raising the heating value of the dewatered sludge in order to enable autothermal combustion. Since first experiments showed very positive results, a full-scale long-term test-run will take place in 2007.

Comparison of sewage sludge treatment systems for regions with hot climate

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
Petia Mijaylova Nacheva ◽  
G. Moeller-Chávez ◽  
E. Ramírez-Camperos ◽  
L. Cardoso-Vigueros
Keyword(s):  
Sewage Sludge ◽  
Alkaline Treatment ◽  
Sludge Treatment ◽  
Tropical Regions ◽  
Aeration Time ◽  
Sludge Stabilization ◽  
Hot Climate ◽  
Aerobic Stabilization ◽  
Sewage Sludge Treatment ◽  
High Pathogenic

The tropical regions have specific problems associated with high pathogenic density in the sewage sludge. The aim of this study was to select an adequate sludge stabilization and valorization system comparing the performance of four technologies: anaerobic stabilization without heating, aerobic stabilization, alkaline treatment with lime and aerobic composting. The study was performed in a pilot plant which was built and operated during six months. The main problem for the beneficial use of the sludge was its pathogenicity. All the systems allowed obtaining stabilized products which met the bacteriological criteria for some kind of use. The compost and the alkalinized sludge were bacteriologically safe for use without restrictions in accordance with the Mexican regulations. The accomplishment of the parasitological criteria for use was however impossible with the anaerobic and with the aerobic systems. The compost obtained at 55-60°C with 25d aeration time and the alkaline sludge fulfill the criteria established by for forest and agriculture use and for soil conditioning. The composting could reach the requirements for unrestricted use when operated at temperatures 65-70°C during 45 days which makes it the most adequate sludge treatment system for hot climate regions.

Treatment and Quality of Sewage Sludge in Germany - Results of a Survey

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Meda ◽  
C. Schaum ◽  
M. Wagner ◽  
P. Cornel ◽  
A. Durth
Keyword(s):  
Sewage Sludge ◽  
Treatment Process ◽  
Wastewater Treatment Plants ◽  
Current Status ◽  
Sludge Treatment ◽  
Sewage Sludge Treatment ◽  
Treatment And Disposal ◽  
German Association ◽  
Entire Treatment

TIn 2004, the German Association for Wastewater, Water and Waste (DWA) carried out a survey about the current status of sewage sludge treatment and disposal in Germany. The study covered about one third of the wastewater treatment plants and about two thirds of the entire treatment capacity (expressed in population equivalents) in Germany. This provides an up-to-date and representative database. The paper presents the most important results regarding sludge treatment, process engineering, current disposal paths and sewage sludge quality.

Estimation of Energy Saving for Melting Process on Sewage Sludge

1991 ◽  
Vol 23 (10-12) ◽  
pp. 2011-2018 ◽  
Author(s):  
T. Murakami ◽  
K. Sasabe ◽  
K. Sasaki ◽  
T. Kawashima
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Energy Saving ◽  
Fuel Consumption ◽  
Melting Process ◽  
System Operation ◽  
Operational Conditions ◽  
Volatile Solids ◽  
Cake Moisture ◽  
Very High

The possible volume reduction and stabilization of the sewage sludge associated with the melting process are expected to be greater than with the incineration process. In addition, melted slag can be utilized. However, since the melting process requires a very high temperature to melt inorganics (ash) in the sludge, the technologies to minimize energy consumption, to establish system operation and to prolong durability of facilities should be developed. This paper discusses the auxiliary fuel consumption as follows.(1)Preparation of a model that provides the auxiliary fuel consumption of the melting system on the basis of the mass and heat balances.(2)Evaluation of the auxiliary fuel consumption in the above model using the cake moisture content, the volatile solids of the cake, the dried cake moisture content and the melting temperature as parameters.(3)Examination of the operational conditions for an energy saving melting system based on the results of (1) and (2) above.

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