Effect on sludge disintegration by EDTA‐enhanced thermal‐alkaline treatment

Abstract

Sludge disintegration is an effective pretreatment to enhance the biodegradability of sludge. At present, the thermal-alkaline is one of the most commonly used methods, but it has a massive consumption of energy and chemical reagents. EDTA-enhanced thermal-alkaline treatment was used to strengthen the dewatered sludge disintegration at mid-low temperature in this study. Results showed that the dissolving-out quantity of soluble chemical oxygen demand and the volatile solid (VS) in residual sludge in the EDTA-added group were 14.7% higher and 7% lower than those in control system without EDTA, respectively, indicating that EDTA addition improved the performance of sludge disintegration. The addition of EDTA loosened the floc structure and enhanced the hydrolyzability of dissolved organic matters (DOM) with a narrower distribution of the relative molecular weight. The membrane damage of microbial cells in EDTA-added group reached 73.3% after 120 min, which was much higher than that in the control group (31.9%). EDTA contains a large number of hydrogen bond acceptors and could form hydrogen bonds with alcohols and phenols in solubilization products and DOM. It was speculated that the mechanism of EDTA-enhanced sludge disintegration was related to the formation of hydrogen bonds between EDTA and organic matter inside and outside the cell. © 2019 Water Environment Federation • Practitioner points• The addition of EDTA facilitated the thermal-alkali cracking of dewatered sludge. • EDTA increased the particle size of sludge and enhanced the hydrolysis of DOM. • The strengthening effect mainly occurred at the beginning of TB-EPS dissolving slowly. • Hydrogen bond played important roles in the enhanced disintegration of sludge by EDTA.

The Effect of Static Magnetic Field on Methanogenesis in the Anaerobic Digestion of Municipal Sewage Sludge

“…Well-implemented AD can reduce susceptibility to putrification, improve sanitary conditions, reduce MSS volume, and produce high yields of CH 4 -rich biogas [13][14][15]. These results are often further bolstered through MSS pretreatment and shredding [16,17], i.e., processes that disrupt the sludge's structure by separating flocs, destroying microbial cells, releasing organic substances and extracellular polymers into the dilute phase, etc. [18,19].…”

Effect of Fe2+ and Fe0 Applied Photo‐Fenton Processes on Sludge Disintegration

“…Disintegration methods can be gathered under four main headings: chemical, mechanical, thermal, and biological methods 6. Sludge disintegration was carried out with different processes, e.g., Fenton process 7, electrocoagulation 8, ultrasonic process 9, thermal‐alkaline treatment 10, thermal energy 11, electro‐oxidation process 12, hydrocyclone pretreatment 13, ultrasound and high voltage 14, and electrochemical process 15 .…”

Nanoscale Copper II Oxide An Efficient and Reusable Adsorbent for Removal of Nickel II from Contaminated Water

“…Hence, treating waste water for removal of contaminants is essential to reduce their mobility within the terrestrial ecosystem 15 . Among the available removal techniques, adsorption is regarded as one of the most extensively used method because of simple design, low cost and no sludge formation 16,[19][20][21] . Nanoscale metal oxides find applications as a cost efficient adsorbent in water treatment and remediation technology due to their small size and adsorption efficiency as compared to natural sized oxide 22 .…”