Dr M.S.Parmar, Pankaj Kumar, Jeeshan

Northern India Textile Research Association

Abstract

Wastewater pollution control is a significant area of scientific research today, particularly in industries with high environmental impact, such as textile processing. The textile processing industry is one of the major contributors to pollution in Panipat district. With growing awareness about environmental preservation, efforts are being made to reduce the consumption of fresh water, chemicals, and energy in these industries. Textile processing requires substantial amounts of fresh water and chemicals during various wet processing stages. A series of studies were conducted in the textile processing industry in Northern India to analyze the specific consumption of water, chemicals, and energy needed to process 1 kg of material. These studies also aimed to identify opportunities to reduce consumption, thereby decreasing the load on effluent treatment plants and minimizing water pollution while saving energy and time. Environmental issues in the textile industry are primarily caused by the discharge of wastewater. This paper presents a critical review of water, chemical, and energy consumption practices in textile processing units in Panipat. The findings are based on a detailed, face-to-face, questionnaire-based survey conducted in 19 textile processing factories, mostly MSMEs, where modified processing methods were implemented. These improvements were possible by slightly changing the methods and chemicals without major investments from the factories. Practical examples from two representative processing units are presented here.

Keywords: Textile effluent, groundwater, wastewater, common effluent treatment plant, dyeing, printing, print washer

1.     Introduction

The textile industry is typically fragmented and, in some cases, involves a complex production system that includes the manufacturing of yarn or fabric, dyeing, printing, and washing. Each segment of the industry requires a substantial amount of inputs, such as raw materials, water, chemicals, and energy. Consequently, these processes result in high levels of waste emissions, including wastewater and greenhouse gases, which put pressure on the environment and pose significant risks to public health1. The textile industry has faced significant criticism due to its environmental impact during both the production and end use of textile products2.

Textile wet processing has several negative environmental impacts, including high water consumption and the discharge of wastewater containing large amounts of organic chemicals and coloring agents. This wastewater often has low biodegradability and high salinity3.

In the textile supply chain, processes such as dyeing, printing, finishing, washing, and other wet processing activities account for 85% of total water use and 65% of the total chemical consumption across all industrial sectors4. As a result, the industry is regarded as one of the most polluting industries due to its significant production and discharge of wastewater, along with the hazardous chemicals it contains5,6. During the wet processing of textile materials, dyes, chemicals, and auxiliaries are added at various stages, depending on the quantity of material to be processed and the amount of water to be used. After the processes are completed, warm or hot water effluent carrying different types and amounts of dyes and chemicals is discharged as wastewater. This wastewater is a complex mixture contaminated with unexhausted or unfixed dyes, dye diluents, various auxiliaries, bleaches, optical brighteners, and other chemicals, including carcinogenic heavy metals used during textile processing7.

In textile wet processing factories, water can be classified into three categories: raw water, which is generally sourced from underground; soft water, created by treating raw water to remove hardness; and wastewater produced during processing. Soft water is used in boilers to generate steam and for various treatment stages, including dyeing and finishing. It is also employed for cleaning tasks within the dyehouse, laboratory work, and pilot processing. However, some factories use soft water for all purposes, leading to both resource and economic losses. Typically, more than 70% of the water used is groundwater, with the remainder allocated for other domestic purposes8.

After processing, residual auxiliaries and their degradation products are routed to the effluent treatment plant (ETP) for primary, secondary, or tertiary treatment. Following these treatments, if the treated effluent complies with permissible limits, it is forwarded to the common effluent treatment plant (CETP). Alternatively, it may be managed through a zero liquid discharge (ZLD) process. The wastewater generated by the textile industry is generally chemically intensive, with the level of contamination varying based on the number of processing stages and the specific application methods used. Typical characteristics of textile wastewater include a wide range of pH values, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), oil and grease, color, and heavy metals.

Panipat is one of the largest producers of textile products in North India and, as a result, is vulnerable to environmental degradation. The processing industries of the Panipat cluster predominantly process polyester as compared to cotton, which means the disperse dye is most commonly used in dyeing and printing. In the case of cotton, reactive dyes are generally used with supporting chemicals like salt, alkali, etc. The major areas of water and chemical consumption in this cluster are identified in the dyeing and washing processes. In this cluster, processing units are equipped with facilities for primary effluent treatment, effluent treatment, and zero liquid discharge (ZLD) to handle and treat the effluent based on their product mixes.

This study aimed to estimate the specific water and chemical consumption required to process 1 kg of material and identify potential savings. Optimizing the process not only reduces chemical consumption but also lowers pollution levels, decreases fresh water usage and energy consumption, cuts fuel consumption, and minimizes greenhouse gas emissions, leading to a more sustainable and efficient processing approach.

2.  Materials and Methods

2.1 Study area

A majority of the units are in the industrial areas of sector 25 (I&II) and sector 29 (I&II), the Haryana Urban Development Authority, and the Panipat industrial area. Other enterprises, such as woolen yarn manufacturing and job work units, are primarily located in and around Panipat Town. This cluster caters to local customers as well as export houses. All medium and large industries, with few small industries, have export businesses, and they have supply chain tie-ups with micro and small industries in the form of job work. The processing industries are connected to a common effluent treatment plant (CETP). There is a total of two CETPs, each with a capacity of 21 MLD. The effluent after treatment is sent to CETP for further treatment. In addition, zero liquid discharge (ZLD) industries treat effluent in their own facilities and are classified as standalone units. The study was centered around sector 25 and sector 29 of the Panipat.

2.2 Research Instrument: Study Questionnaire

The NITRA team of experts developed a structured questionnaire, carefully designed to collect baseline data from the industry. The baseline data includes information on the industry profile, product mixes, machinery setup and operation, daily production, and daily consumption of water, chemicals, and agrofuels. It also covers supporting systems such as boilers, thermoelectric heaters, compressors, basic effluent treatment plants, and water supply systems.

2.3 Sampling

The study used a purposive sampling approach to select the units. After choosing the units for study, the assessment team visited the units to collect baseline data. The total number of textile units for the project was 45 units. 19 textile units were chosen for doing primary surveys to collect data for the baseline assessment study.

2.4 Data Collection

The processing industries were surveyed, and data was gathered through a structured questionnaire. The study team pinpointed areas of water and chemical usage, evaluated the performance of Effluent Treatment Plants (ETPs) and the characteristics of effluents, reviewed current work practices on the shop floor, analyzed processing methods, and engaged with the shop floor team and unit managers to discuss relevant issues. Analysis of water consumption in the processing factories of the Panipat cluster was conducted using an ultrasonic flow meter in some of the cases due to the unavailability of water monitoring systems and the inadequate performance of existing flow meters. Additionally, various techniques and methods were employed to establish the water balance for each factory. The dyes and chemicals consumption data was either provided by the head or representative of the department as requested. In most of the cases, the relevant data was absent. In contrast, some factories provided partial data, possibly due to the non-availability of data or the sensitivity of data. Similar to the analysis of water consumption, chemical consumption was also successfully calculated through a thorough study.

3. Results and Discussion

Table 1 represents the basic information about the investigated factories. It comprises mostly dyeing and printing units with cotton and polyester product mixes. The wastewater treatment plants were mostly physico-chemical and biological. Few of the industries have the facility of zero liquid discharge (ZLD).

Table 1. Details of the factories from where data is collected

3.1 Water consumption to process per kg of material

Figure 1 summarizes the specific water consumption required to process 1 kg of material across 19 industries. This data applies to cotton, polyester, and their substrates. The findings indicate that the amount of water used ranges from approximately 23 to 77 liters per kilogram of textile fabric, depending on the stage of processing. On average, 45 liters of water are used to process 1 kg of textile material. Variations in water usage are due to factors such as different product mixes, varying depths of shades, additional steps in dyeing and washing, and processes like rinsing and overflow. Water consumption can vary due to several factors, including the lack of proper management systems, the absence of measuring instruments, outdated machinery, and inadequate maintenance. Overflow and rinsing practices are the most common factors according to the manufacturing textile products of this cluster, where water consumption is very high due to these processes, but these can be minimized through process optimization. Although a reduction in water use of 5 to 10% can often be achieved by implementing simple measures such as fixing water leaks, using spray guns for cleaning, and repairing broken or missing valves.

Besides, installation of auto controller devices on dyeing machines, vacuum slit on stenter machines, recycling of ETP water, and adopting technological development can potentially reduce water consumption in the Panipat textile cluster. Further reductions in water consumption can be achieved by focusing on internal recycling, recovering condensed water, reclaiming water from various sources, and ultimately reducing freshwater consumption on a daily basis. In a nutshell, at least a 30 percent reduction in water consumption can be achieved in the Panipat cluster. The specific water consumption (L/kg) across 19 units shown below in Fig. 1.

Fig 1. Water Consumption Across 19 Industries

3.2 Water uses and wastewater generated

Table 2 presents the intake of fresh water, water consumption in the process, and the corresponding wastewater generated for each individual unit connected to the CETP, all measured in liters per day.

Table 2. Intake of fresh water, water usage in process and corresponding wastewater generated

The study shows that intake of fresh water could be minimized through increasing the internal recycling and recycling of treated water from ETP and decreasing the water consumption in the process through optimization of the process as previously discussed. In view of this, NITRA analyzed the water balance across the 19 industries. As a reference, the analysis of water balance shown in Table 3.

Table 3. Water Balance

The study of water balance across 19 industries revealed that, in most cases, internal recycling and the recycling of treated water from the ETP are either very limited or non-existent.

3.3 Chemical consumption to process per kg of material

Figure 2 illustrates the chemical consumption required to process 1 kg of material across 19 industries. On average, 114 g of chemicals are used per kg of textile material, with consumption ranging from 32 g/kg to 244 g/kg. This applies to both cotton and polyester, as well as their substrates. In the Panipat factories, which primarily process polyester, various dyes and chemicals are used to ensure effective interaction and uniform fixation of dyes on the textile substrate. Due to polyester-based units, two major chemicals, i.e., sodium hydroxide and sodium hydrosulphite are consumed in different processes. Similarly, reactive dyeing of cotton textiles requires significant quantities of inorganic salts and alkalis for efficient dye exhaustion and fixation. When these salts and alkalis are discharged into effluent, they contribute to high levels of total dissolved solids (TDS), leading to environmental pollution. The specific chemical consumption (g/kg) across 19 units shown below in fig. 2.

Fig 2. Chemical Consumption Across 19 Industries 

3.4 Average chemical consumption

Figure 3 shows the major chemicals used in textile processing, with specific individual consumption in tonnes/month.

Fig 3. Average Chemical Consumption Across 19 Industries 

It has been revealed from the study that the reduction of chemical consumption can be enabled through process optimization in the pretreatments, dyeing and washing process, including modification/technological development in processing machines, Additionally, the development of an in-house chemical management system, recovering silicone, and reducing consumption of salt and alkali with the use of smart techniques while consuming salt and soda during reactive dyeing. In summary, at least a 25 percent reduction in chemical consumption can be achieved in the Panipat cluster.

3.5 Process Optimization in Jigger Machine (Unit PT-011)

In the investigated industry, an average of 65 liters of water and 176 grams of chemicals are consumed to process 1 kg of fabric. The company produces two main types of products, i.e., cotton, which accounts for approximately 70% of their output, and polyester, which makes up the remaining 30%. The facility is equipped with extensive wet processing machinery, including four soft flow dyeing machines with capacities ranging from 100 to 600 kg and ten Jigger dyeing machines with capacities ranging from 500 to 1200 kg.

NITRA identified significant opportunities to conserve water, chemicals, and energy in the investigated industry. NITRA studied a pretreatment process on the Jigger machine, specifically RFD (Ready for Dyeing), where cotton fabric first undergoes the desizing process at 60 ºC. After the desizing process is completed, the bath is drained, and the material proceeds to the second process, scouring. The scouring process is conducted at 70–80 ºC in an alkaline pH of 13–14. After the scouring process is completed, the bath is drained, and the material is ready for the next process, bleaching. The bleaching process uses a universal bleaching agent, hydrogen peroxide, and is carried out also at 70-80 ºC with maintaining the pH 10.5-10.8. In peroxide bleaching, a stabilizer is used to control the decomposition rate of hydrogen peroxide. After the bleaching process is completed, the bath is drained.

During the study, it was observed that there were two drainings between the scouring and bleaching processes, each followed by washes. The study revealed that the existing process involves too much consumption of water, time, chemicals, and energy.

In view of this, NITRA modified the existing RFD (Ready for Dyeing) and implemented a gentle scouring and bleaching process. This process was modified in such a way that scouring and bleaching are done in the same bath. This reduces water consumption by up to 18.5%, chemical consumption by up to 14.9%, and saves 20% of the processing time, all while achieving the same results as the previous process. Additionally, the modified process also enables results in energy, electricity, and cost savings. In the modified process, sodium hydroxide and hydrogen peroxide are combined in one bath, with the pH carefully maintained between 10 and 10.5. This adjustment aims to optimize the generation of perhydroxyl ions, which are the primary active agents in the bleaching process. By maintaining an alkaline pH, the process enhances the efficiency of the hydrogen peroxide while minimizing chemical waste and reducing overall processing time. This approach not only simplifies the bleaching procedure but also potentially improves the consistency of the bleaching results and lowers operational costs. Additionally, it leads to a reduction in the environmental impact by decreasing the volume of wastewater. This optimization not only reduces water consumption but also lowers pollution levels, decreases energy usage, cuts fuel consumption, and minimizes greenhouse gas emissions, leading to a more sustainable and efficient processing approach. The estimated potential savings on the Jigger machine are outlined below in Table 4.

Table 4. Comparison of conventional vs. NITRA modified process

The NITRA modified process on the jigger machine has been effectively implemented in industry (Code PT-011), achieving savings in the context of water of approximately 3,21,360 liters per month 4,776,200 kcal of energy per month, 775.57 kg of chemicals per month, and 463.5 kWh of electricity per year, 17,222 kg of Agrofuel per year and a reduction of 27.46 kg of CO₂ per year in greenhouse gas emissions.

3.6 Energy Conservation in Jet Dyeing Machine (Unit PT-001)

In the investigated industry, an average of 38 liters of water and 66 grams of chemicals are consumed to process 1 kg of fabric. The company mainly produces 100% polyester fabrics. The facility is equipped with extensive wet processing machinery, including four Jet dyeing machines long tube and U Shape with capacities ranging from 500 to 1000.

NITRA identified significant opportunities to conserve water, chemicals, and energy in the investigated industry. NITRA studied an Insulation/cladding on Jet dyeing machines to save energy. During the jet dyeing process, the internal temperature of the machine reaches up to 130°C, while the external surface temperature is around 35°C. This difference leads to thermal energy loss as heat dissipates into the atmosphere. By insulating the jet dyeing machine with a layer of mineral glass wool and aluminum, we have successfully maintained temperature uniformity within the batch of processed fabric, ensuring stable internal temperature and reducing heat loss. The estimated potential savings on the Jigger machine are outlined below in Table 5.

Table 5. Saving potential by Insulation/cladding on Jet dyeing machine

3.7 Process Optimization on Print Washer (Unit PT-004)

In the investigated industry, an average of 23 liters of water and 62 grams of chemicals are consumed to process 1 kg of fabric. The company specializes in 100% polyester fabrics, primarily for bed sheet manufacturing. The facility is equipped with extensive wet processing machinery, including three U-shaped jet dyeing machines with a capacity of 350 kg each, a rotary screen-printing machine, and a print washer.

After printing, polyester fabric undergoes processing in print washers to remove unfixed dyes and residual chemicals. Typically, print washers consist of 8–13 chambers; however, this facility uses a setup with 9 washing chambers. In each chamber, the fabric is treated with specific chemicals and hot water. Observations by NITRA revealed that the chemical consumption, particularly of sodium hydrosulphite and caustic soda, was unusually high due to a lack of process optimization. The facility employed outdated methods, including using sodium hydrosulphite at boiling temperatures (up to 95°C), which is scientifically incorrect. This practice not only led to faster chemical loss but also increased overall chemical and fuel consumption.

To address these inefficiencies, NITRA experts installed an automatic temperature controller and a pneumatic control valve to regulate steam usage, maintaining the water temperature at an optimized 75°C. This intervention significantly reduced chemical evaporation, water usage, and fuel consumption, thereby enhancing the overall process efficiency. The estimated potential savings on the Print washer machine are outlined below in Table 6.

Table 6. Saving potential by process optimization on Print washer machine

4. Limitations

Many factories do not regularly maintain relevant data, and some have not provided comprehensive information across all categories. The challenges in obtaining factory data contribute to the limited scope of these studies. To address this, NITRA utilized reverse engineering to estimate water, chemical, and energy consumption through various methods. Primary data on water, chemicals, and agro-fuel usage was collected from sources such as government-supplied fresh water, process house water, and wastewater. This was accomplished through a structured questionnaire, supplemented by discussions with shop floor teams and factory owners.   

5. Conclusion

The textile industry generally faces significant environmental challenges, particularly concerning water footprints, wastewater treatment, and the use of hazardous chemicals. Panipat wet processing factories are mostly polyester-based, with few cottons. This cluster mainly manufactures home furnishing products and consumes a lot of water to process the material. In view of this, dispersed dyes are extremely used to process the polyester material as compared to reactive dyes. Jet dyeing, soft flow dyeing, hank dyeing, jigger dyeing, and paddle dyeing are generally used to process textile home furnishing products like bed sheets, curtains, bath mats, carpets, durree, and blankets.

This study can serve as a benchmark for evaluating the environmental impact of water, wastewater, chemicals, and fuel while also highlighting opportunities for improvement. The study indicates that enhancing awareness about effective water and chemical management practices and processes and supporting adoption of technological tools will contribute to enhancing the environmental sustainability of the Panipat textile cluster.

Notably, the study indicates that water usage could be reduced by up to 30% and chemical usage by up to 25% after modifying the process and adopting new techniques. Along with this, time, energy, and cost will also be reduced.

6. References:

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2. Niinima¨ki K, Peters G, Dahlbo H, Perry P, Rissanen T, Gwilt A. The environmental price of fast fashion. Nat Rev Earth Environ [Internet]. 2020 Apr 7 [cited 2020 Oct 26]; 1(4):189–200. Available from: https:// www.nature.com/articles/s43017-020-0039-9

3. Vajnhandl S, Valh JV. The status of water reuse in European textile sector. J Environ Manage. 2014 Aug 1; 141:29–35. https://doi.org/10.1016/j.jenvman.2014.03.014 PMID: 24768832

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5. Gu¨mu¨ş D, Akbal F. Photocatalytic degradation of textile dye and wastewater. Water Air Soil Pollut. 2011 Mar; 216(1–4):117–24

6. Vajnhandl S, Valh JV. The status of water reuse in European textile sector. J Environ Manage. 2014 Aug 1; 141:29–35. https://doi.org/10.1016/j.jenvman.2014.03.014 PMID: 24768832

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Acknowledgment

The authors gratefully acknowledge Mr. J. K. Srivastava, Head, Fiber Excellence Centre, Coraplast Industries, Valsad, Gujarat, for his valuable time, professional review, and critical examination of the present study. His consideration of the work and recognition of its relevance to contemporary environmental challenges are sincerely appreciated.

The present study, entitled “Studies on Pollution and Possible Approaches to Minimize Wastewater Discharge and Maximize Water Reuse,” addresses the increasingly important issues of wastewater generation, environmental pollution, water conservation, and sustainable utilization of water resources. The study explores possible approaches for reducing the discharge of wastewater into the environment and for recovering and retaining a greater proportion of water for appropriate reuse.

Water is a critical natural resource, and the responsible management of industrial wastewater has significant implications for environmental protection and sustainable development. In this context, the study seeks to identify practical and technically feasible measures that may assist in minimizing wastewater discharge, improving water recovery, and promoting the principles of reduce, recover, recycle, and reuse.

The authors believe that the observations and recommendations presented in this work may provide a useful basis for further technical investigation, process optimization, and development of sustainable wastewater-management practices. The study may also contribute to broader efforts towards reducing the environmental impact of industrial activities while supporting more efficient and responsible utilization of water resources.

The authors sincerely thank Mr. J. K. Srivastava for his review and encouragement and gratefully acknowledge his contribution towards strengthening the relevance and direction of this study. The authors further hope that this work will stimulate continued research, innovation, and practical implementation in the areas of wastewater treatment, water recovery, water reuse, pollution prevention, and sustainable industrial water management.