Treatment of TMAH solutions from the microelectronics industry: A combined process scheme

Innocenzi, Valentina; Zueva, Svetlana; Prisciandaro, Marina; Michelis, Ida De; Renzo, A. Di; Celso, Giuseppe Mazziotti di; Vegliò, Francesco

doi:10.1016/j.jwpe.2019.100780

Cited by 17 publications

(10 citation statements)

References 28 publications

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“…The aim of the project was to implement a TMAH biological treatment plant on a pilot scale, which went into operation in 2018. Subsequently, the project demonstrated that the biodegradation of TMAH into non-toxic substances and ammonia can take place on an industrial scale using aerobic biological treatment, with an efficiency greater than 99% (Innocenzi et al 2019). The new technology plant provided treatment of line 1 by neutralisation with sulphuric acid, followed by biological treatment (De Michelis et al 2019) (Fig.…”

Section: Methodsmentioning

confidence: 99%

Social life cycle assessment of an innovative industrial wastewater treatment plant

Serreli

Petti

Raggi

et al. 2021

Int J Life Cycle Assess

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Background The social impacts generated by industrial waste treatment processes have not been studied enough, as shown in the literature. Social life cycle assessment studies have mainly focused on the assessment of products and less on industrial waste, especially wastewater, although potentially relevant from an environmental point of view, and also from a social one for various stakeholders. Purpose This case study concerns the social assessment of an innovative technology to treat the wastewater of a microelectronics company. In order to produce electronic components and semiconductors, the company has to treat and dispose of relevant wastewater streams containing various toxic substances. The wastewater streams need to be treated in order to protect the eco-system, representing a high cost for the company and a potential impact on the environment. For this reason, the company developed a LIFE project to demonstrate the viability to decrease the burdens on water bodies. The positive outcome of the test on the pilot plant paved the way for the construction of the full-scale plant that will treat all the wastewater generated by the company. The objective of this paper is the socio-economic assessment of a full-scale plant designed to treat three different kinds of wastewater. Methods The assessment of socio-economic potential impacts of a new technology has been carried out through the PSILCA (Product Social Impact Life Cycle Assessment) database implementation to evaluate 65 social indicators of a wastewater treatment plant. Results The line with the highest impact is the one which treats tetramethylammonium hydroxide; this is because this wastewater flow is the most abundant (14 and 43 times greater than the other wastewaters, respectively). The most affected stakeholder is the Local Community, followed by the Actors of the Value Chain; in fact, the results referred to the functional unit considered exceed 300,000 medium risk hours in both cases. For the Local Community this result arises from the indicator “Contribution to environmental load,” which is understandable considering the object of the study since this indicator includes health effects. As far as the Value Chain Actors stakeholder is concerned, the two indicators most impacted are “Corruption” and “Social responsibility along the supply chain”. The analysis conducted has also shown that upstream has a fundamental relevance for the social risks detected. Conclusions Considering the current lack of studies on both environmental and social impacts of wastewater treatment, and the fact that Social Life Cycle Assessment has not been widely used in this field, as emerged from literature review, this work is the first use of the PSILCA database to assess an industrial wastewater plant. The use of a social life cycle assessment database allows the value chain of a product system to be considered: the results show that most of the overall social risk derives from upstream sectors.

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Section: Methodsmentioning

confidence: 99%

Social life cycle assessment of an innovative industrial wastewater treatment plant

Serreli

Petti

Raggi

et al. 2021

Int J Life Cycle Assess

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“…This solution is an additional waste stream produced by the manufacturing processes of LFoundry: it is a mixture of organic substances, mainly 1-methoxy-2-propanol, with a total organic carbon (TOC) concentration of around 615 g/L. It was added as a source of carbon, in order to supply the optimal C/N ratio for the bacterial metabolism, that should be 20 by weight [21]. Such a ratio is indeed too low, around 3.5 in the TMAH molecule, thus the second waste stream R2 was added to the previously mentioned stream R1; • a growth medium, whose composition is shown in Table 1.…”

Section: Feed Compositionmentioning

confidence: 99%

“…The sample's volume was refilled by the addition of the growth medium. The kinetic parameters of the Monod model were also calculated for the design of the pilot bioreactor [21].…”

Section: Biological Testsmentioning

confidence: 99%

“…where the coefficients m and β are null (product associated to the growth), the biomass yield Y G X/S is 0.34 g of biomass per g of substrate, and α = 0.2 g of ammonium per g of biomass (experimental values). The detailed calculation can be found in Innocenzi et al [21]. Such an approach allows the fitting of substrate depletion data versus time to the integrated Monod equation by using nonlinear regression, which is advantageous since µ max and K S may be calculated from a single progress curve [23].…”

Section: Kinetic Modelmentioning

confidence: 99%

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Aerobic Treatment of Waste Process Solutions from the Semiconductor Industry: From Lab to Pilot Scale

et al. 2019

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Tetramethylammonium hydroxide (TMAH) is widely used as a solvent in the semiconductor industry. After the photo-impression process, it is necessary to remove the photoresist (PR) layer from the surface of the circuits; for this purpose, a TMAH solution is usually used. This chemical compound is highly toxic and corrosive and cannot be discharged into the environment. This study was carried out in collaboration with LFoundry (SMIC group), in order to prove the feasibility of biodegradation under aerobic conditions, using microorganisms coming from the LFoundry’s wastewater treatment plant (WWTP) at different operating conditions. The feed composition was modified in order to add a small but increasing amount of TMAH and PR. The aim was to verify if the increase of TMAH concentration was harmful to bacteria. The feed stream, containing TMAH and PR, was the only carbon source for the metabolism of the aerobic microorganisms. The results of this study demonstrated an effective biological degradation of TMAH and showed a total removal efficiency of more than 99.3%, with a final concentration of 7 mg/L. Moreover, the kinetic parameters of the Monod model were also calculated. The results obtained from the experimental campaign were used to design a pilot plant that will treat around 25 L/h of waste TMAH/PR solution.

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“…In most chemical treatments, phosphorus can be removed by precipitation with a metal salt, e.g., iron, aluminum and calcium salts [11]. In wastewater with high fluoride content, the most commonly adopted method is precipitation under calcium fluoride form (CaF 2 ), using different calcium salts (CaCl 2 , Ca(NO 3 ) 2 •4H 2 O, and hydrated lime Ca(OH) 2 ) as precipitants [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Zero-Liquid Discharge Treatment of Wastewater from a Fertilizer Factory

et al. 2020

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This article describes the improvement of wastewater treatment in a fertilizer plant located in Central Italy (municipality of Vasto). In this facility, water is used for the removal of dust and fluorinated gases from the air. The resulting wastewater contains fluorides and phosphates in hazardous forms. Its treatment ordinarily does not result in a Zero-Liquid Discharge (ZLD) process. To achieve this purpose, several reagents were tested, focusing on the correlation linking pH, type of reagent and the effect on the separation of fluorides and phosphates from the wastewater. It was eventually found, and explained with a model, that hydrated lime at pH = 12 was so effective as a precipitating agent that phosphate and fluoride separation reached a value of 99.9%, thus allowing for reuse of the water in the plant process. Furthermore, phosphates and fluorides precipitated in a non-hazardous form, so that the material could also be recycled. In synthesis, wastewater treatment of the fertilizer plant was upgraded so that it became a ZLD process coupled with the recovery and recycling of fluorides and phosphates.

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Treatment of TMAH solutions from the microelectronics industry: A combined process scheme

Cited by 17 publications

References 28 publications

Social life cycle assessment of an innovative industrial wastewater treatment plant

Social life cycle assessment of an innovative industrial wastewater treatment plant

Aerobic Treatment of Waste Process Solutions from the Semiconductor Industry: From Lab to Pilot Scale

Zero-Liquid Discharge Treatment of Wastewater from a Fertilizer Factory

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