Effects of air parameters on sewage sludge drying characteristics and regression analyses of drying model coefficients

2021 ◽  
Vol 198 ◽  
pp. 117501
Author(s):  
Qiushuang Zheng ◽  
Ziyuan Hu ◽  
Penggang Li ◽  
Long Ni ◽  
Guanying Huang ◽  
...  
Author(s):  
Sang Hyun Oh ◽  
Ki Ho Park ◽  
Byoung Hyuk Yu ◽  
Sung Il Kim

The purpose of this study is to analyze the changes of drying efficiency according to the inflow conditions of outside air into the drying equipment during the drying process in order to reduce the energy used in the drying process of sludge. We conducted the experiment using a vertical thin film dryer. Materials used for the experiment are sewage sludge. As a result of the study, higher drying efficiency was obtained in the case of outside air inflow than in the case of no outside air inflow. In addition, optimum condition of outside air inflow was derived. Keywords: Drying; Sludge; Drying efficiency; Air inflow condition 


2013 ◽  
Vol 334-335 ◽  
pp. 365-368 ◽  
Author(s):  
Hou Lei Zhang ◽  
Xin Zhi Liu ◽  
Shu Guang Zhu ◽  
Bin Li

Sewage sludge from wastewater treatment is being more and more produced in many countries. For sewage sludge disposal, drying operation is usually required and greatly energy-consuming. Paddle dryers, one kind of indirect dryers, are widely used in removing moisture of sewage sludge recently, but the design, to some extent, still depends on empirical and limited data. In this paper, we presented preliminary experimental results of sewage sludge drying based on a 3 m2paddle dryer prototype. The effects of thermal oil inlet temperature on outlet moisture content and mass flowrate of initial sludge are recorded and analyzed. A simple monotonic relation between mass flowrate of initial sludge and thermal oil inlet temperature does not exist. Besides, we performed the drying experiment of adding low-value biomass (rice husk) into wet sewage sludge. The results show that the drying performance is improved significantly.


Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1927 ◽  
Author(s):  
Dinko Đurđević ◽  
Paolo Blecich ◽  
Željko Jurić

Croatia produced 21,366 tonnes of dry matter (DM) sewage sludge (SS) in 2016, a quantity expected to surpass 100,000 tonnes DM by 2024. Annual production rates for future wastewater treatment plants (WWTP) in Croatia are estimated at 5.8–7.3 Nm3/people equivalent (PE) for biogas and 20–25 kgDM/PE of sewage sludge. Biogas can be converted into 12–16 kWhel/PE of electricity and 19–24 kWhth/PE of heat, which is sufficient for 30–40% of electrical and 80–100% of thermal autonomy. The WWTP autonomy can be increased using energy recovery from sewage sludge incineration by 60% for electricity and 100% of thermal energy (10–13 kWhel/PE and 30–38 kWhth/PE). However, energy for sewage sludge drying exceeds energy recovery, unless solar drying is performed. The annual solar drying potential is estimated between 450–750 kgDM/m2 of solar drying surface. The lower heating value of dried sewage sludge is 2–3 kWh/kgDM and this energy can be used for assisting sludge drying or for energy generation and supply to WWTPs. Sewage sludge can be considered a renewable energy source and its incineration generates substantially lower greenhouse gases emissions than energy generation from fossil fuels. For the same amount of energy, sewage sludge emits 58% fewer emissions than natural gas and 80% less than hard coal and fuel oil. Moreover, this paper analysed the feasibility of sludge disposal practices by analysing three scenarios (landfilling, co-incineration, and mono-incineration). The analysis revealed that the most cost-effective sewage sludge disposal method is landfilling for 60% and co-incineration for 40% of the observed WWTPs in Croatia. The lowest CO2 emissions are obtained with landfilling and mono-incineration in 53% and 38% of the cases, respectively.


2014 ◽  
Vol 69 (9) ◽  
pp. 1859-1866 ◽  
Author(s):  
Hui-Ling Wang ◽  
Zhao-Hui Yang ◽  
Jing Huang ◽  
Li-Ke Wang ◽  
Cheng-Liu Gou ◽  
...  

As dewatered sludge is highly viscous and sticky, the combination of foaming pretreatment and drying process seems to be an alternative method to improve the drying performance of dewatered sludge. In this study, CaO addition followed by mechanical whipping was employed for foaming the dewatered sludge. It was found that the foams were stable and the diameters of bubbles mainly ranged from 0.1 to 0.3 mm. The drying experiments were carried out in a drying oven in the convective mode. The results indicated that foamed sludge at 0.70 g/cm3 had the best drying performance at each level of temperature, which could save 35–45% drying time to reach 20% moisture content compared with the non-foamed sludge. The drying rate of foamed sludge at 0.70 g/cm3 was improved with the increasing of drying temperature. The impact of sample thickness on drying rate was not obvious when the sample thickness increased from 2 to 8 mm. Different mathematical models were used for the simulation of foamed sludge drying curves. The Wang and Singh model represented the drying characteristics better than other models with coefficient of determination values over 0.99.


2018 ◽  
Vol 263 ◽  
pp. 94-102 ◽  
Author(s):  
Qian Li ◽  
Xuebin Lu ◽  
Haigang Guo ◽  
Zengjun Yang ◽  
Yingte Li ◽  
...  

Author(s):  
Wan Yu ◽  
jun Yang ◽  
Peisheng Li ◽  
Yi Hu ◽  
Jie Li ◽  
...  

2016 ◽  
Vol 52 (11) ◽  
pp. 2367-2379 ◽  
Author(s):  
Hüseyin Pehlivan ◽  
Asude Ateş ◽  
Mustafa Özdemir

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