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Waste Management
Published in Ronald Fayer, Lihua Xiao, Cryptosporidium and Cryptosporidiosis, 2007
Biodrying is a form of composting that uses forced aeration along with the heat generated by natural aerobic decomposition to dry the manure mix. Collick et al. (submitted) examined a biodrying process for the treatment of dairy cow manure using eggs of the pig roundworm, Ascaris suum, as the indicator pathogen based on the assumption that A. suum is typically more difficult to kill than the eggs, cysts, and oocysts of most other parasites. The dairy cattle manure was piled into a biodrying storage shed. The forced aeration and natural decomposition processes heated a major portion of the waste pile to temperatures exceeding 55°C. The A. suum eggs were inoculated into special chambers and placed at three different elevations at intervals along the length of the pile. No viable eggs were recovered from any of the chambers removed from the compost pile. The complete inactivation of these helminths' eggs by the process suggests that it would also be successful in the inactivation of oocysts.
Advances in Biodrying of Sludge
Published in Shusheng Pang, Sankar Bhattacharya, Junjie Yan, Drying of Biomass, Biosolids, and Coal, 2019
César Huiliñir Curío, Francisco Stegmaier, Silvio Montalvo
According to this background, biodrying can be defined as the process where microorganisms aerobically degrade the organic matter in the wastes, a process in which metabolic heat is produced, converting the liquid water contained in the organic wastes into water vapour which is then transported and removed by airflow (Navaee-Ardeh et al., 2006; Velis et al., 2009; Yang et al., 2017). Therefore, metabolic heat production, air convection, and molecular diffusion of oxygen and water vapour are the main mechanisms involved in water removal from wet wastes by biodrying (Frei et al., 2004). A scheme of the process is shown in Figure 3.1.
The biodrying process of sewage sludge – a review
Published in Drying Technology, 2020
Renan Felicio dos Reis, Joao Sergio Cordeiro, Xavier Font, Cali Laguna Achon
Biodrying consists of a process that can be applied to drying previously dewatered sewage sludge, which must be conducted in a way that does not allow the loss of heat to the atmosphere, and takes place in hermetic or semi-hermetic reactors. The process is activated through biological activity that degrades the organic matter present in the sludge and releases heat. Biodrying increases the temperature inside the matrix, which results in breaking apart sludge particles due to the energy released and, consequently, in the evaporation of water fractions that requires a higher level of energy to be removed and still remain present in the matrix. Therefore, free spaces within the sludge matrix are necessary and are created by the addition and mixing of bulking agent to the dewatered sludge. Air injection facilitates the contact of the aerobic decomposer microorganisms with oxygen, activates biological activity, and the evaporated water is removed by convection, since the injected air has inflow and outflow channels in the reactor. Moreover, because biodrying presents a relatively low removal of volatile solids (VS) from the matrix at the end of the process, it is a method that has been considered attractive for energy generation, given the heating value of the biodried waste.
Lignocellulose biodegradation in the biodrying process of sewage sludge and sawdust
Published in Drying Technology, 2018
Han-Yan Zhang, Thomas Krafft, Ding Gao, Guo-Di Zheng, Lu Cai
The treatment and disposal of sewage sludge has become a worldwide environmental challenge due to strict legal regulations, land shortages, rising costs, and public awareness and concern.[1] Biodrying, a technique that relies on aerobic fermentation, maximizes water removal from biomass waste using the microbial heat generated from organic matter degradation.[2] With increasing amounts of sewage sludge worldwide, biodrying has become a competitive treatment method compared to composting because of its shorter treatment duration and ability to partially achieve biologic stability.[3456] It is also competitive with thermal drying because of its lower investment and operational cost.[7] Zhang et al.[8] reported that a biodrying plant in China treats 1000 tons/day of sewage sludge within 21 days. Scaglia et al.[9,10] found that a treatment period of longer than 4 weeks did not result in a significant increase in the degree of biologic stability. Biodrying can either be used to pretreat compost, coupled with a maturing period after the biodrying, or be used as a treatment to make biofuel or soil amendments.[11,12]
Biodrying performance and bacterial community structure under variable and constant aeration regimes during sewage sludge biodrying
Published in Drying Technology, 2018
Zhi-Ying Wu, Lu Cai, Thomas Krafft, Ding Gao, Li Wang
Activated sludge process is used extensively to treat municipal wastewater. This process generates a large amount of waste sewage sludge (SS). Increasingly strict restrictions on SS disposal as well as sludge reuse requirements have made sludge treatment more challenging and costly.[1] Aerobic fermentation is a widely used method to treat SS. Derived from aerobic fermentation, biodrying is a technique that is oriented toward maximizing water removal from biomass waste, using the microbial heat generated from organic matter degradation.[2,3] This is different from another aerobic fermentation technique, composting, which focuses on biological stability and maturity. Compared to thermal drying, biodrying generally requires lower investment and operational costs.[4,5]