Evaluation of methanogenic treatment of TMAH (tetra-methyl ammonium hydroxide) in a full-scale TFT-LCD wastewater treatment process

Abstract

This study evaluated TMAH biodegradation under methanogenic conditions. Under methanogenic conditions, a sludge from a full-scale UASB treating TFT-LCD wastewater was able to degrade 2,000 mg/L of TMAH within 10 h and attained a specific degradation rate of 19.2 mgTMAH/gVSS-h. Furthermore, several chemicals including some surfactants, DMSO, and sulfate were examined for their potential inhibitory effects on TMAH biodegradation under methanogenic conditions. The results indicated that surfactant S1 (up to 2%) and DMSO (up to 1,000 mg/L) presented negligible inhibitory effects on TMAH degradation, while surfactant S2 (0.2-1%) might inhibit methanogenic reaction without any TMAH degradation for 3-5 h. At sulfate concentrations higher than 300 mg/L, a complete inhibition of methanogenic reaction and TMAH biodegradation was observed. Results from cloning and sequencing of archaeal 16S rRNA gene fragments showed that Methanosarcina barkeri and Methanosarcina mazei were the dominant methanogens in the UASB treating TMAH-containing TFT-LCD wastewater.

Kinetic analysis of biological degradation for tetramethylammonium hydroxide (TMAH) in the anaerobic activated sludge system at ambient temperature

“…From this awareness the anaerobic process was pointed out to outcompete with conventional activated sludge processes, with which could reduce expenses for aeration and waste sludge treatment [10,11]. For treating the medium-strength TMAH wastewater using the anaerobic process, an up-flow anaerobic sludge blanket process (UASB process) was recently demonstrated in a full-scale plant in Taiwan [2,7,8]. The UASB process receiving about 1000 mg/L of TMAH successfully removed the compound by 70-90% at a mesophilic condition of 35 • C with corresponding biogas production.…”

Toxicity of tetramethylammonium hydroxide to aquatic organisms and its synergistic action with potassium iodide

“…The average concentration of TMAH in a biological treatment plant for TFT-LCD wastewater was recorded as 1528 mg L -1 (Hu et al, 2012). Efficient and cost-effective technologies for TMAH removal from wastewater are being explored and yet to be introduced (Hu et al, 2010;Nishihama et al, 2010).…”

Electrodialysis Process for the Recycling and Concentrating of Tetramethylammonium Hydroxide (TMAH) from Photoresist Developer Wastewater

“…The conventional distillation can be used for this spent developer wastewater treatment, but it is an energy-consuming process and the TMAH is easy to be degraded into trimethylamine and methanol. Currently, a range of methodologies is available for treating developer wastewater, such as chemical oxidative method, absorption, , and biological degradation. − The most proposed metabolic pathway for TMAH biological and chemical oxidative decomposition is that TMAH is first oxidized to formaldehyde and ammonium, and then TMA decomposed to N 2 , H 2 O, and CO 2 by the microorganism strains or combined thermal decomposition and oxidation catalyst . Biological processes are still the main technology in treating full-scale TMAH-containing wastewater, but the biological method is relatively a difficult and time-consuming process due to the nonbiodegradable property of TMAH. , The catalytic oxidation method requires large amounts of a costly platinum catalyst.…”