Supercritical water oxidation of sludges contaminated with toxic organic chemicals

2000 ◽  
Vol 42 (7-8) ◽  
pp. 363-368 ◽  
Author(s):  
N. Crain ◽  
A. Shanableh ◽  
E. Gloyna
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Paper Mill ◽  
Pilot Scale ◽  
Supercritical Water Oxidation ◽  
Pulp And Paper Mill ◽  
Remediation Technology ◽  
University Of Texas ◽  
The University ◽  
Hazardous Compounds

Supercritical water oxidation (SCWO) is a proven technology for the treatment of contaminated organic wastes. Bench and pilot-scale work completed at The University of Texas at Austin's SCWO Laboratory have proven the technology effective for treating a variety of sludge types, including sludge contaminated with hazardous compounds. The studies included pulp and paper mill sludges and sludges derived from the treatment of municipal and industrial wastewaters. The results presented in this paper confirmed that the removal of the organic component of sludge, including the trace toxic organic compounds, using SCWO exceeded 99.9%. For example, the results show that the destruction removal efficiencies (DRE's) of the PCBs reached 99.99% in the contaminated sludge. No dioxins or furans were detected in the gaseous effluent resulting from the treatment of the PCB-contaminated sludge. These results demonstrate the technical effectiveness of SCWO as a sludge remediation technology.

Experimental Study on Supercritical Water Oxidation of Paper Mill Sludge

2014 ◽  
Vol 955-959 ◽  
pp. 711-715 ◽  
Author(s):  
Li Li Qian ◽  
Shu Zhong Wang ◽  
Jie Zhang
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Paper Industry ◽  
Paper Mill ◽  
National Standards ◽  
Supercritical Water Oxidation ◽  
Paper Mill Sludge ◽  
Temperature Oxidation ◽  
Liquid Products ◽  
Transparent Liquid

Paper industry produces large amounts of sludge with about 65wt% moisture content. Due to its complex composition, the charge of traditional disposal method is high and easy to bring about secondary pollution. In this paper, the influences of temperature, oxidation coefficient and residence time on the performance of supercritical water oxidation (SCWO) of paper mill sludge were investigated. The results show that SCWO can almost completely eliminate organics in sludge and obtain transparent liquid products meeting relative national standards at 550°C, 5min with an oxidation coefficient of 3.0. However, during this process, TN changes to NH3-N, so NH3-N in liquid products increases with operation parameters, indicating the recalcitrant nature of NH3-N, and which needs further treatment.

Supercritical Water Oxidation – Wastewaters and Sludges

1991 ◽  
Vol 23 (1-3) ◽  
pp. 389-398 ◽  
Author(s):  
Abdullah Shanableh ◽  
Earnest F. Gloyna
Keyword(s):  
Acetic Acid ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Biological Treatment ◽  
Treatment Plant ◽  
Transformation Products ◽  
Pilot Scale ◽  
Supercritical Water Oxidation ◽  
Temperature And Pressure ◽  
Dimethyl Phenol

Environmental contaminants can be eliminated through the use of SCWO techniques. A comprehensive supercritical oxidation (SCWO) research laboratory, including bench and pilot-scale facilities has been developed. High temperature and pressure systems slightly less than and greater than supercritical water conditions can be used for the efficient destruction of waste biological treatment plant sludges, acetic acid, 2-nitro phenol, 2,4-dimethyl phenol, phenol, and 2,4-dinitro toluene. Above 400 °C, near complete destruction of sludge and transformation compounds such as acetic acid can be achieved with relatively short residence times. Ammonia and acetic acid are transformation products in the SCWO of biological treatment plant sludges. Acetic acid produced from the oxidation of sludge is oxidized rapidly at supercritical temperatures, 400 °C to 450 °C.

Simulation of Supercritical Water Oxidation with Air at Pilot Plant Scale

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Belén García Jarana ◽  
Jezabel Sánchez Oneto ◽  
Juan Ramón Portela Miguélez ◽  
Enrique Nebot Sanz ◽  
Enrique J. Martínez de la Ossa
Keyword(s):  
Kinetic Parameters ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Pilot Plant ◽  
Reaction Kinetic ◽  
Pure Water ◽  
Kinetic Equations ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Supercritical Water Oxidation

Supercritical Water Oxidation (SCWO) processes have been studied by numerous researchers. The effectiveness of this approach to treat a wide variety of wastes has been proved and the kinetics involved in some cases have been described. Phenol is commonly present in industrial wastewaters and it is extremely toxic. Hence, phenol is a model pollutant that has been the subject of numerous studies by SCWO on a laboratory scale. In this work, a pilot-scale SCWO system has been used to compare experimental and predicted conversions in the SCWO of phenol, using the reaction kinetic equations obtained at the laboratory scale. In this context, “PROSIM PLUS” software was employed to develop a simulator for the pilot plant facility, with the reaction kinetic parameters adjusted to represent the experimental data. In this study it was necessary to determine the thermal losses between the experimental reactor and its surroundings. These thermal losses were obtained from tests with pure water and oxidant streams in the absence of chemical reaction. An equation that predicted the effect of flow rate and temperature on the thermal losses was used. Experimental oxidation tests were conducted with initial temperature in the range 380 to 425 ºC, at 250 bar and phenol concentrations ranging from 1 to 12 g/l. Good agreement in the simulation was obtained by adjusting the kinetic parameters within their confidence range. This simulator was used to optimize the SCWO of phenol solutions in the pilot plant facility.

Design of the first pilot scale plant of China for supercritical water oxidation of sewage sludge

2012 ◽  
Vol 90 (2) ◽  
pp. 288-297 ◽  
Author(s):  
Donghai Xu ◽  
Shuzhong Wang ◽  
Xingying Tang ◽  
Yanmeng Gong ◽  
Yang Guo ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Pilot Scale ◽  
Supercritical Water Oxidation

scholarly journals Supercritical water oxidation of octol – containing wastewater

2019 ◽  
Vol 21 (2) ◽  
pp. 172-179 ◽  
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Reaction Times ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Performance Criteria ◽  
Optimum Operating ◽  
Toxicity Tests ◽  
Supercritical Water Oxidation ◽  
Product Analysis

<p>This study investigated optimum operating conditions of supercritical water oxidation (SCWO) for octol and compared the degradation of its components TNT (2,4,6-trinitrotoluene) and HMX (octahydro-1,3,5,7- tetranitro-1,3,5,7-tetrazocine, octogen) under the same conditions. Pilot scale experiments were conducted at various temperatures, reaction times and oxidant amounts. Removal efficiency, by-product analysis and toxicity tests were selected as the performance criteria for the SCWO. Optimum conditions were determined as a temperature of 500 C, 120 s of oxidation time and an oxidant ratio of 150%. Removal of octol was achieved at a rate of 99.99%, while TNT and HMX were removed individually at a rate of ~85% when they existed in the wastewater. No toxicity was observed at the end of the octol oxidation, whereas toxicity was found in the TNT and HMX oxidation due to the formation of TNT isomer and aniline. Higher initial organic material concentrations promoted the removal rates. These results demonstrated that SCWO can be effectively used for the degradation of ammunition wastewater even when concentrations are high.</p>

Engineering aspects of supercritical water oxidation

1994 ◽  
Vol 30 (9) ◽  
pp. 1-10 ◽  
Author(s):  
E. F. Gloyna ◽  
L. Li ◽  
R. N. McBrayer
Keyword(s):  
Supercritical Water ◽  
Water Oxidation ◽  
Process Integration ◽  
Reaction Medium ◽  
Development Program ◽  
Supercritical Water Oxidation ◽  
University Of Texas ◽  
Chemical Company ◽  
Processing Facility ◽  
Disposal Option

This paper emphasizes the engineering aspects of supercritical water oxidation (SCWO), including organic destruction, inorganic solubility, corrosion, catalysis, heat transfer, and treatability studies. The development program involving a 2.5 liter-per-minute SCWO pilot-plant is described. Also, design considerations for the commercial SCWO processing facility, including materials of construction, reactor design, heat recovery, control strategy, safety requirements, and process integration are discussed. The University of Texas at Austin (UT) and Eco Waste Technologies (EWT), respectively, are involved in research and development of SCWO technology. This R&D effort has resulted in the design and construction of a commercial SCWO processing facility for the Texaco Chemical Company located in Austin, Texas. The facility will become operational in early 1994. SCWO technology relies on the unique properties of supercritical water to create a useful and effective reaction medium. The SCWO system is capable of operating as a totally enclosed treatment facility, providing complete destruction, and meeting regulatory effluent requirements. As such, this technology is an environmentally attractive, safe and economic wastewater treatment and sludge disposal option.

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