Is ZLD suitable for semiconductor and textile industry?

Photo: Saltworkstech

The Centre is examining various options of moving forward on the country’s Zero Liquid Discharge (ZLD) policy to ensure that investment in emerging sectors such as semiconductors is not hampered while the environment continues to be protected. 

ZLD is a closed-loop wastewater management system ensuring that no industrial wastewater is discharged outside the plot boundary of the manufacturing plant or the industrial park in which the plant is situated.

According to the report on BusinessLine, “The Department for Policy on Investments and Internal Trade (DPIIT) has been getting suggestions for removing regulatory compliances such as Zero Liquid Discharge to encourage investments in sectors like semiconductors. Any decision on removing regulatory compliances will be taken only after consulting all sectors.” 

ZLD in semiconductor industries

Despite various policies by successive governments to start semiconductor manufacturing in India, the country is yet to set up a private sector chip fabrication plant (fab) in India.

Semiconductor fabs consist of front-end fab manufacturing and back-end assembly. 

In July, Minister of Commerce and Industry Piyush Goyal asked the Indian industry to set up a semiconductor fabrication plant in India. Currently, India imports all semiconductor fabs from China and this push by Goyal comes under the Atma Nirbhar Bharat (self-reliant India) mission and the growing tensions on the Sino-Indian border. 

A semiconductor industry requires good infrastructure, high technology with good logistics, guaranteed water and power, a central waste-water treatment facility, and on-site availability of speciality and bulk electronic gases and chemicals.

Apart from the lack of infrastructure and skilled labour which creates hurdles in the path of setting up semiconductor fabs in India, environmental regulations like ZLD also affect the growth of fabs.

According to Arun Gandhi, Engineering & Construction Leader specializing in Advanced Manufacturing Facilities, “India’s environmental regulations demand a ‘Zero Liquid Discharge’ (ZLD) for wastewater management. This mandates that there should be no discharge of industrial wastewater outside the site boundary of the manufacturing plant.”

ZLD has a goal to ensure 100% treatment and recycling of water but the requirement of the recycled water to be contained within the boundary of the plant premises is not feasible in the semiconductor industry, he says.

Over the last decade many ambitious semiconductor projects in India have failed to progress from drawing board to reality, says Gandhi. “Apart from factors relating to business and financial incentives package offered, the fact that India-specific environmental regulations are not aligned with global norms have also contributed to the decision to drop these projects,” he adds.

Speaking about how ZLD has affected foreign investment, he says that one of the largest PV manufacturers did not invest in India because of ZLD norms. The foreign company has plants in various other countries with advanced manufacturing hubs where the norms are not as restrictive as India,.

“In India, we frame new tougher laws to compensate for lax implementation of existing laws,” says Gandhi. According to him those companies which are firmly committed to following the norms will find it tough. This will create problems in attracting investment, he adds. Instead, we should review how the global leaders in semiconductor manufacturing are approaching the problem of treatment and discharge of industrial wastewater, while still addressing the environmental concerns 

Since computer chip manufacturing requires large volumes of ultrapure water, to clean silicon wafers at multiple stages of the Fab process, ZLD is not the most suitable for the fabs. 

A report by Byron, mentions that the use of ZLD in the semiconductor industry often results in contamination of the product. Other issues regarding the implementation of ZLD, mentioned in the report are higher capital, engineering concerns and solid brine effluents.

The report also throws light on the advantages of ZLD in the semiconductor industry. “The data shows that although treatment and recycle make use of a greater amount of capital, energy, and consumables, treatment and discharge uses more water and disposal costs,” it says.

Water condition in India

The need for water conservation is one of the most pressing global issues that the world is facing. Throughout the globe, there is an overall shortage of water resulting from the effects of climate change and the rapid increase in world population.

India which has only 4% of freshwater needs to switch to sustainable use of its water resources. With over 1.3 billion population there is a greater demand for natural resources and even greater challenges to deal with increasing environmental problems.

The World-Wide Fund (WWF) in its latest WWF Water Risk filter report said 30 Indian cities will face ‘severe risk’ by 2050 unless immediate actions are taken to curb and mitigate climate change.

According to UNICEF, less than 50% of the population in India has access to safely managed drinking water. It also mentions waterborne diseases have an economic burden of approximately USD 60 million in a year in India. “Two-thirds of India’s 718 districts are affected by extreme water depletion, and the current lack of planning for water safety and security is a major concern.”

Why is ZLD required?

Industries like pharma, pulp and paper, tanneries, textile dyeing, chemical, power plants and many more generate wastewater with high salinity. The conventional treatment method does not remove salinity in the treated effluents which contaminate the groundwater and surface water when discharged.

ZLD was started by the United States to preserve Colorado river from increased salinity due to power plant discharges. 

Tirupur-the first district to implement ZLD

In 2008 Tamil Nadu became the first state to mandate ZLD in the textile factories in Tirupur. The textile industries in Tirupur used to dump all the wastewater in the Noyyal river which resulted in the death of livestock and people developing skin disease.

The farmers’ association has been fighting a legal battle against the dyeing and bleaching units in the district since 2003. The Madras High Court and Tamil Nadu Pollution Control Board instructed the bleaching and dyeing units in Tirupur to implement effluent treatment plans to meet the ZLD norms in 2006 

In February 2011, the Madras High Court ordered the 700-odd dyeing units in Tirupur to be shut down as they were not complying with the court’s 2006 order to ensure ZLD. 

Tirupur’s journey had a mixed impact on the local communities and the textile industry. According to a study by Jenny Gronwall and Anna C. Jonsson, Tirupur’s journey inspired federal law and policy reform to mainstream ZLD as a standard. 

However, the impact of this journey came at a high price to the businesses whose reconfigurations were dismissed by the court as failing to achieve ZLD. 

“This resulted in closing down of their operations either for periods of time or permanently, and an ensuing loss of income for a very large group of workers,” claims the study. 

Use of ZLD in textile sectors

Textile industry is one of the oldest and economically beneficial sectors of India and it is highly water-intensive. To curb the excessive use of water, its insufficiency, conservation and issues related to water disposal, the government has implemented ZLD in textile units.

In the textile dyeing process, salt is added to enhance the process. The combined effluent from textile plants is highly coloured, having a high content of organic load and extremely high total dissolved solids. 

The Common Effluent Treatment Plant (CETP) generally provides treatment only up to the secondary level due to which the total dissolved solid content does not get completely removed from the discharged treated effluent. Therefore, regulatory bodies made it mandatory for all the textile industries with the effluent discharge of more than 25-meter cube/day to set up a ZLD facility.

According to the Tamil Nadu Pollution Control Board report, 95% of permeate water is recovered from the RO plant in the ZLD system for textile processing industries. 

While ZLD plays an important role in water recycling, there is another side of the coin which needs to be highlighted. 

According to research on Tamil Nadu textile plants at Tirupur, the total carbon footprint of a ZLD treatment plant was observed to 1.36 times the carbon footprint of a conventional treatment facility plant. 

It also generates hazardous solid waste which poses disposal challenges. In some cases, the solids can be used as a fill material if it complies with the state environmental regulations. However, if the solid waste is hazardous it is being sent to landfills resulting in more landfills.

Since most of the textile units in India are small and medium scale, putting up a new ZLD compatible plant requires more land which is very costly. Moreover, the cost of maintaining ZLD is quite high which affects the commercial viability of ZLD for the textile units.

The ZLD system is highly sophisticated and needs skilled and experienced manpower for its efficient operation which increases the overall cost of treatment, operation as well as maintenance.

Many sectors in India are being directed by the State Pollution Control Boards (SPCB) to adopt ZLD technology. Since there is no national ZLD policy, the SPCB takes decisions based on specific geographical areas and the amount of waste generated. Owing to a lot of implementation charges, it is creating problems for manufacturers especially those who are short of funding. 

Photo: Saltworkstech