Viscosity dynamics and the production of extracellular polymeric substances and soluble microbial products during anaerobic digestion of pulp and paper mill wastewater sludges
| Autor: | Eva-Maria Ekstrand, Luka Šafarič, Annika Björn, Bo H. Svensson |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Paper
010504 meteorology & atmospheric sciences Hydraulic retention time 0208 environmental biotechnology Industrial Waste OLR Bioengineering 02 engineering and technology 01 natural sciences Waste Disposal Fluid Extracellular polymeric substances Soluble microbial products Extracellular polymeric substance Bioreactors Sludge bulking Effluent 0105 earth and related environmental sciences Rheology Sewage Chemistry business.industry Viscosity Paper mill General Medicine Other Industrial Biotechnology Pulp and paper industry 020801 environmental engineering Anaerobic digestion Activated sludge Wastewater Annan industriell bioteknik business Biotechnology Research Paper |
| Zdroj: | Bioprocess and Biosystems Engineering |
| ISSN: | 1615-7605 |
| Popis: | The production processes of the pulp and paper industry often run in campaigns, leading to large variations in the composition of wastewaters and waste sludges. During anaerobic digestion (AD) of these wastes, the viscosity or the production of extracellular polymeric substances (EPS) and soluble microbial products (SMP) may be affected, with the risk of foam formation, inefficient digester mixing or poor sludge dewaterability. The aim of this study was to investigate how viscosity and production of EPS and SMP during long-term AD of pulp and paper mill sludge is affected by changes in organic loading rate (OLR) and hydraulic retention time (HRT). Two mesophilic lab-scale continuous stirred tank reactors (CSTRs) were operated for 800 days (R1 and R2), initially digesting only fibre sludge, then co-digesting fibre sludge and activated sludge. The HRT was lowered, followed by an increase in the OLR. Reactor fluids were sampled once a month for rheological characterization and analysis of EPS and SMP. The production of the protein fraction of SMP was positively correlated to the OLR, implicating reduced effluent qualities at high OLR. EPS formation correlated with the magnesium content, and during sulphate deficiency, the production of EPS and SMP increased. At high levels of EPS and SMP, there was an increase in viscosity of the anaerobic sludges, and dewatering efficiency was reduced. In addition, increased viscosity and/or the production of EPS and SMP were important factors in sludge bulking and foam formation in the CSTRs. Sludge bulking was avoided by more frequent stirring. Electronic supplementary material The online version of this article (10.1007/s00449-019-02224-4) contains supplementary material, which is available to authorized users. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink