Electrochemical treatment of sewage sludge and pathogen inactivation
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RESEARCH ARTICLE
Electrochemical treatment of sewage sludge and pathogen inactivation Maasoomeh Jafari1 · Gerardine G. Botte1 Received: 6 June 2020 / Accepted: 10 September 2020 © Springer Nature B.V. 2020
Abstract Treatment and disposal of sewage sludge is still a worldwide challenging problem. Improper sludge treatment results in severe environmental impact and endangering public health. Moreover, sewage sludge disposal is a cost-intensive process. Therefore, pathogen removal and solid reduction are indispensable for sludge disposal management. In this study, a novel electrochemical method in alkaline media was developed to break down the sludge structure at room temperature. A reduction of 24.85% in total solids and 46.42% in volatile solids was achieved, which represents approximately a 25% reduction in the sludge disposal cost when compared to conventional treatment methods. Also, a 90% reduction in energy consumption was demonstrated when compared to other electrochemical methods. The post-processed samples characterization showed that a large quantity of organic material was released from the sludge samples into the liquid phase, which indicates the potential to reduce the residence time in anaerobic digesters and to generate more biogas. The proposed treatment demonstrated the feasibility of pathogen removal and biosolid production for safe landfilling or agriculture applications such as fertilizers. Graphic abstract
Keywords Sludge electrolysis · Alkaline treatment · Electrochemical pathogen deactivation · Ammonia production · Agricultural grade biosolids
* Gerardine G. Botte [email protected] Extended author information available on the last page of the article
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1 Introduction Sewage sludge is considered as the main byproduct of wastewater treatment processes and can cause adverse environmental effects due to pathogenic organisms if not managed and disposed of properly [1]. Population growth correlates with increasing solid waste generation, thus impacting municipal waste treatment facilities (WWTP). In 2007, the United States (U.S.) sewage sludge amounted to 7.2 million tons, equating to 0.14 lb of sewage per person per day [2]. Considering sludge is anywhere from 79 to 99% water, significant processing (via anaerobic digesting, dewatering, thickening, conditioning, composting, etc.) is required to reduce its volume and to convert it into biosolids (defined as sludge that has been treated to meet the Environmental Protection Agency—EPA—standards). Typically, sludge treatment and biosolids disposal represent 50 to 60% of the operational costs in municipal wastewater treatment plants (WWTP) [3]. Conventional methods for biosolids disposal are landfilling and incineration, which are capital and energy-intensive [4]. In any case, the biosolids need to meet the U.S. EPA pollutant and pathogen requirements for land application and surface disposal [5]. Consequently, it is compulsory to disinfect the biosolids before disposal. Recently, treatment techniques such as pyrolysis,
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