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24. Modeling TOC breakthrough in granular activated carbon adsorbers

Author

Zachman, Bradley A. and Summers, R. Scott

Subjects
Carbon -- Properties, Adsorbents -- Properties, Adsorbents -- Usage, Water -- Purification, Water -- Methods, Engineering and manufacturing industries, Environmental issues
Abstract

Linear regression techniques were used to develop practical models to predict total organic carbon (TOC) breakthrough in bituminous granular activated carbon (GAC) adsorbers. Models were developed for two field-scale GAC sizes (8x30 and 12 x 40 mesh) and two empty bed contact times (EBCTs) (10 and 20 min). Model input parameters include two water quality variables, influent TOC concentration (TO[C.sub.0]) and pH, that impact performance. The dependent variables for the models were normalized breakthrough time, throughput in bed volumes, to six fractional (TOC/TO[C.sub.0]=0.2, 0.3, 0.4, 0.5, 0.6, and 0.7) and three mass (TOC=1.0, 1.5, and 2.0 mg/L) effluent concentrations. Model development was performed using small-scale breakthrough data from 35 different source waters; external model validation was performed with small-scale breakthrough data from 14 source waters; a sensitivity analysis was performed to ensure that the models effectively capture expected breakthrough trend; and a scalability test was performed to verify the models' ability to predict breakthrough for field-scale GAC adsorbers. DOI: 10.1061/(ASCE)EE.1943-7870.0000145 CE Database subject headings: Activated carbon; Adsorption; Water treatment; Organic matter; Granular media. Author keywords: Activated carbon treatment; Water treatment; Models; Natural organic matter.

Published
2010

29. Contributors

Author

Alchouron, Jacinta, Alherbawi, Mohammad, Aller, Deborah, Alwis, Y. Vindula, Arwenyo, Beatrice, Bakshi, Santanu, Banik, Chumki, Bentley, Matthew J., Brown, Robert C., Bursztyn Fuentes, Amalia L., Camps-Arbestain, Marta, Capareda, Sergio C., Carrasco, Catalina, Chaubey, Abhishek Kumar, Dhaka, Rahul Kumar, Dhaka, Sarita, Fernando, Janeshta C., Fidel, Rivka, Ganguly, Arna, Garcia-Nunez, Jesus, Garcia-Perez, Manuel, Garcia-Perez, Tsai, Gugolz, Stefanie, Gunatilake, Sameera R., Jain, Karuna, Jamison, Hailey, Karunaratne, Tharindu, Keel, Michela Grace, Kennedy, Anthony M., Lassi, Ulla, McKay, Gordon, Mlsna, Todd E., Mohan, Dinesh, Mood, Sohrab Haghighi, Musser, Abigail, Nanney, Andie L.M., Navarathna, Chanaka, Nzengung, Valentine, Parthasarathy, Prakash, Patel, Manvendra, Peiris, Chathuri, Pelaez-Samaniego, Manuel Raul, Pittman, Charles U., Jr., Pratap, Tej, Priyantha, Namal, Ramirez, Arissa, Rani, Pooja, Rodrigo, Prashan M., Romar, Henrik, Sajjad, Samra, Saleem, Junaid, Sanjeewa, Prasad, Shimabuku, Kyle K., Siipola, Virpi, Singh, Balwant, Singh, Krishna Pal, Summers, R. Scott, Thrikawala, Vishmi S., Trakal, Lukáš, Uddin, Md Mosleh, Vega, Andrea S., Venson, Beverly, Wang, Tao, Wewalwela, Jayani J., Wright, Mark Mba, Yadama, Vikram, Zhang, Jilei, and Zhang, Xuefeng

Published
2022
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31. Full factorial study of pipe characteristics, stagnation times, and water quality.

Author

Tolofari, Dienye L., Masters, Sheldon V., Bartrand, Tim, Hamilton, Kerry A., Haas, Charles N., Olson, Mira, Summers, R. Scott, Rasheduzzaman, Md, Young, Audrey, Singh, Rajveer, and Gurian, Patrick L.

Abstract

This study examines the effect of pipe characteristics and stagnation time on nitrification, disinfectant loss, and organic carbon concentrations. Pipe racks consisting of different pipe materials (chlorinated polyvinyl chloride [CPVC], cross‐linked polyethylene [PEX‐B], and copper), diameters (0.75 and 0.5 in.), and water stagnation times (1 week and 12 hr) were set up in two cities with different disinfectants (chloramine and free chlorine) and different corrosion control (orthophosphate vs. pH/alkalinity adjustment). Copper pipe material had lower residual concentrations relative to plastic pipe in both water systems. In the chloramine system, residual concentrations were lower for smaller‐diameter pipes, whereas diameter did not strongly influence residual concentration in the chlorine system. Total organic carbon (TOC) increased during stagnation in the chloramine system. Nitrification was observed in the chloramine system for stagnation times of 1 week and 12 hr, indicating that flushing as frequently as every 12 hr may not be an effective mechanism for nitrification control in building plumbing. [ABSTRACT FROM AUTHOR]

Published
2020
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49. High Temperature Co-pyrolysis Thermal Air Activation Enhances Biochar Adsorption of Herbicides from Surface Water.

Author

Kearns, Joshua P., Shimabuku, Kyle K., Knappe, Detlef R.U., and Summers, R. Scott

Subjects
ACTIVATED carbon, BIOCHAR, ADSORPTION capacity, DISSOLVED organic matter, MICROPORES
Abstract

Recent interest has arisen in the use of biochar as a low-cost adsorbent for control of organic micropollutants in water. However, compared with activated carbon (AC), biochar adsorption capacity is typically one to two orders of magnitude lower. This study reports batch mode adsorption of anionic (2,4-D, C0 100 μg/L) and neutral (simazine [SZN], C0 1.5 μg/L) herbicides from surface water containing dissolved organic matter at 4 mg/L total organic carbon concentration. Enhanced adsorption was observed by biochars generated from updraft gasifiers under conditions of simultaneous co-pyrolysis thermal air activation (CPTA). 2,4-D adsorption by ≥850°C CPTA biochars was more than 10 times greater on a mass basis compared with biochars generated from a conventional anoxic pyrolysis (CAP) reactor and was equivalent to AC reference adsorbents on a surface area normalized basis. Biochars generated at ≥850°C under CPTA conditions had similar micropore surface area to CAP biochars (∼330 m2/g) but about 2.5 times the mesopore surface area (∼110 m2/g CPTA, ∼40 m2/g CAP), suggestive of increased pore accessibility generated by thermochemical widening of pores and/or removal of pyrolysis tars by CPTA. 2,4-D adsorption from surface water was shown to correlate strongly with biochar H:C molar ratio within but not between biochars grouped by CAP and CPTA generation conditions. Comparing adsorption of 2,4-D and SZN by biochars generated from CAP and CPTA conditions suggested that herbicide interaction with biochar surface functional groups through formation of charge-assisted H-bonds did not play a significant role in herbicide uptake from surface water. [ABSTRACT FROM AUTHOR]

Published
2019
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