Structure modification and extracellular polymeric substances conversion during sewage sludge biodrying process.
Biodrying, an economical and energy-saving biomass waste treatment, removes water from waste using the biological heat generated by organic matter degradation. Technical limitations associated with dewatering complicate the biodrying of sewage sludge. This study investigated the sludge alteration associated with its water removal, focusing on sludge form, extracellular polymeric substances, and free water release. An auto-feedback control technology was used for the biodrying; a scanning electron microscope was used to record the morphological change; three-dimensional excitation-emission matrix fluorescence spectroscopy was used to analyze extracellular polymeric substances (EPS) variation, and time domain reflectometry was used to assess the free water release. Over the 20-day biodrying, there was a 62% water removal rate during the first thermophilic phase. Biodrying created a hollow and stratified sludge structure. Aromatic proteins and soluble microbial byproducts in the EPS were significantly degraded. The thermophilic phase was the phase resulting in the greatest free water release.
Faculty of Architectural, Civil Engineering and Environment, Ningbo University, Ningbo, China; Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
Lu
L
Cai
Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
Thomas
T
Krafft
Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China. Electronic address: chentb@igsnrr.ac.cn.
Tong-Bin
TB
Chen
Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
Ding
D
Gao
Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
Li
L
Wang
D018533:Biomass; D006358:Hot Temperature; D011108:Polymers; D012722:Sewage / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
D011108:Polymers; D012722:Sewage; D014867:Water
Biodrying; Extracellular polymeric substances; Free water; Morphological change; Sewage sludge