STUDIES ON BUILDING CERAMICS MANUFACTURING BY INCORPORATING DRIED SLUDGE

2014 ◽  
Vol 13 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Marcela Muntean ◽  
Anna-Maria Szoke ◽  
Ovidiu Dumitrescu ◽  
Sandor Meszaros
Keyword(s):  
1987 ◽  
Vol 19 (8) ◽  
pp. 139-145
Author(s):  
G. Castillo ◽  
A. Ortega

The reutilization in agriculture of the sludge produced in the chemical treatment of sewage is investigated. Aluminium sulfate (50 mg/l) and sodium hydroxide (50 and 200 mg/l) are added to domestic sewage allowing it to settle and eliminating floating materials. Three kinds of raw chemical sludge are digested and dried. Their sanitary quality is determined by two bacterial indicators (total and fecal coliforms) and one viral indicator (E. coli bacteriophage) and the fertilizing capability of digested and dry sludge by sowing leguminous crops (Phaseolus spp ) in soil with 11 tons/ha sludge application rate. Digested and dried sludge from conventional treatment in equal conditions to those of chemical sludge is used as reference. Sanitary quality results show that raw and digested chemical sludge are not recommended for use in agriculture due to their high microbiological contamination. Dry sludge could be considered for this purpose due to its low fecal organisms content. However the development of leguminous crops in soil with dry aluminium sludge application shows no seed germination. The results of leguminous growth in digested sludge of sodium hydroxide (200 mg/l) justify an additional treatment to adequate its sanitary quality for use in agriculture.


1993 ◽  
Vol 28 (11-12) ◽  
pp. 341-345
Author(s):  
Shigeki Minami ◽  
Hidekazu Nagasawa ◽  
Yoshinori Saito ◽  
Motoharu Yamagishi ◽  
Masakatsu Hiraoka ◽  
...  

Continuous operation data were obtained on a fluidized bed incineration plant with dryers, and two autoregressive models were then prepared through statistical analysis of the data. Based on the results, an automatic plant control system using fuzzy theory was designed. An incinerator system of this type is characterized by energy efficiency, for which optimum and stable moisture control of the dried sludge is important. The large difference in time constants between incinerator and dryers makes energy saving difficult. Based on these analyses and design, control operations at a commercial plant with a capacity of 150 wet-tons/day were studied. It was confirmed that reduction of auxiliary fuel consumption and reduction of CO and NOx in the exhaust gas were optimized, while the moisture content of dried sludge and the furnace temperature were kept stable.


1996 ◽  
Vol 34 (3-4) ◽  
pp. 469-473
Author(s):  
Paul Lowe ◽  
Michael Brown ◽  
Kathleen Hudson

There appears to be a limited experience world-wide in the application of thermal drying technology to processing raw undigested sludge. This limited experience has shown that the products from raw sludge processing have a much lower bulk density than those from digested sludge. The apparent reason for this phenomenon demonstrated by this work, is the high concentration of fibres in the raw undigested sludge. Different sludges show varying degrees of fibre concentration with a decrease in fibre content as the proportion of secondary sludge increases. The relationship between the bulk density of the product and the fibre content are given and this shows that as the fibre content increases the bulk density of the product will fall. It is recommended that a compaction/pelletisation stage is included in the process stream for high fibre sludges.


2021 ◽  
Author(s):  
Wittawat Wulyapash ◽  
Awassada Phongphiphat ◽  
Sirintornthep Towprayoon

Abstract Large amounts of sludge are generated from wastewater treatment in seafood processing industries. Most of the dewatered sludge in Thailand is not utilized and disposed by landfilling. The dried sludge utilization as refuse-derived fuel (RDF) is an alternative solution due to the gross calorific value (GCV), which is greater than 21.9 MJ/kg. However, the key obstacle is its high moisture content of 87.4% (wet basis). Therefore, drying methods using hot air and microwave techniques were investigated for preparing dried sludge. The effects of hot air temperatures (100-150 °C) and microwave power levels (100-800 W) were compared on drying kinetics, specific energy consumption (SEC), and characteristics of the dried products. The results showed that drying times were decreased by increasing the hot air temperatures. In the same way, the increase in microwave power levels decreased the drying time. The application of microwaves contributed to reducing the drying time by more than 46% compared to the hot air. The reduction of drying times resulted in the saving SEC. The GCV of the dried sludge decreased with the decrease in the volatile matter (VM) due to the high component of VM as 79.5-80.3% (dry ash-free basis). The sludge dried by the microwaves showed a lower GCV than the hot air products. However, dried sludges still had high GCV (≥ 20.8 MJ/kg). Furthermore, the minimal variation of the product characteristics demonstrated that the microwave technique could be applied as an alternative drying method with a rapid process compared to the conventional hot air technique.


Energetika ◽  
2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Giedrius Stravinskas ◽  
Anupras Šlančiauskas

The recent tendency of sewage sludge disposal is targeted towards the gasification for heat generation in small towns far from waste incineration plants. The scope of this article is to present the investigation into the mixture of dried sewage sludge and wood pellets during pyrolysis by thermogravimetry (TG) with evolved gas analysis by TG-coupled Fourier transformation infrared spectroscopy (FTIR) method. The maximum intensity of mass loss of sewage sludge material occurs at 300–310°C temperature and it differs from wood cellulose case of 360°C. The 50:50% mixture of these materials was investigated in more details. Pyrolysis reaction kinetics is described by a variation of three constituent parts from TG data. Prefactor A and activation energy E of the Arrhenius law were found, and reaction order n was determined by the Ozawa method employing Avrami phase change. The maximum of gas evolution is always related to the most intense mass loss, and gas composition correlates with the initial material.


2021 ◽  
Vol 209 ◽  
pp. 91-104
Author(s):  
Fatemeh Kariminejad ◽  
Samira Baghchevan Ghadimi ◽  
Farhad Rahmini ◽  
Mohsen Haghighi ◽  
Rojiar Akbari Sene ◽  
...  

2020 ◽  
Vol 12 (6) ◽  
pp. 2500 ◽  
Author(s):  
Li Ping ◽  
Gang Zhao ◽  
Xiaohu Lin ◽  
Yunhui Gu ◽  
Wei Liu ◽  
...  

Cement manufacturing and the treatment of sludge are considered both energy-intensive industries and major greenhouse gas (GHG) emitters. However, there are still few studies on comprehensive carbon footprint analysis for adding municipal sludge in the cement production. In this study, the lime-dried sludge blended with calcium oxide at the mass mixing ratio of 10% was utilized as raw material for the preparation of Portland cement. The chemical and physical properties of sludge were analyzed. A set of carbon footprint calculation methods of lime-drying treatment of sludge and reuse in cement kilns was then established to explore the feasibility of coprocessing lime-dried sludge in cement kilns. The results showed lime-dried sludge containing CaO, SiO2, Al2O3, and Fe2O3 was ideal for cement production as raw material. However, the water content of lime-dried sludge should be strictly limited. The lime-drying process presented the biggest carbon emission (962.1 kg CO2-eq/t sludge), accounting for 89.0% of total emissions. In the clinker-production phase, the lime-dried sludge as raw material substitute and energy source gained carbon credit of 578.8 and 214.2 kg CO2-eq/t sludge, respectively. The sludge used for producing cement clinker could reduce carbon emissions by 38.5% to 51.7%. The addition ratio of lime and stacking time in the sludge lime-drying process could greatly affect the carbon footprint of coprocessing lime-dried sludge in cement kiln.


2010 ◽  
Vol 10 (5) ◽  
pp. 848-859 ◽  
Author(s):  
A. Uwimana ◽  
I. Nhapi ◽  
U. G. Wali ◽  
Z. Hoko ◽  
J. Kashaigili

A study was carried out to characterize the sludge produced at Kadahokwa Water Treatment Plant (KWTP) in Butare to assess the effectiveness of the sludge treatment and potential impacts of sludge disposal on the environment. Parameters analyzed were chromium, nickel, cadmium, lead, copper, zinc, iron, manganese, aluminium, total nitrogen, total phosphorus, potassium and cation exchange capacity (CEC). The results showed that 450±244.5 tons (dry weight) of sludge are produced annually. The concentrations of heavy metals in the sludge were below the standard limits for land application set by different countries. The high concentrations of nickel (42.3±2.5 ppm), chromium (29.9±6.2 ppm), cadmium (1.1±0.3 ppm) and lead (31.6±3.7 ppm) in the dried sludge posed a pollution risk for the wetland. The CEC was 28.4–33.3 cmol (+)/kg and pH was 6.50–7.45. It was concluded that the KWTP sludge is a poor source of total carbon, a moderate source of nutrients (NPK), and an important source of micronutrients, making it generally suitable for reuse for crop production. The CEC showed that the sludge could improve soil nutrient and water holding capacity. The higher concentration of aluminium (280 ppm) in the sludge creates an opportunity for recycling.


2019 ◽  
Vol 98 (2) ◽  
pp. 27-34
Author(s):  
Akira SUAMI ◽  
Nobusuke KOBAYASHI ◽  
Yoshinori ITAYA
Keyword(s):  

2019 ◽  
Vol 79 (10) ◽  
pp. 1897-1904 ◽  
Author(s):  
Katarzyna Glińska ◽  
Mohammed Aqlan ◽  
Jaume Giralt ◽  
Esther Torrens ◽  
Agusti Fortuny ◽  
...  

Abstract Industrial wastewaters and their treatment are now placed at the heart of the environmental concerns that industries face. Some research work has been carried out in order to limit the impact of these wastes on the environment as well as their costs. In this study, wastewater dehydrated sludge (55% wt. water content) from the paper industry was used to recover cellulose by using tetrakis(hydroxymethyl)phosphonium chloride, [P(CH2OH)4]Cl, ionic liquid as a solvent. The ionic liquid has shown remarkable results in terms of cellulose extraction in addition to its non-volatility and lower toxicity compared to organic volatile solvents. All cellulose, based on dry sludge, was recovered from the industrial dehydrated sludge with better operation conditions. The influence of temperature and the quantity of ionic liquid was preliminary studied in order to optimise the extraction conditions.


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