Impact of Textile Effluents on Different Components of Environment
Author: Dr. Indu Chopra
Rapid industrialization and urbanization has led to growth of various large and small industrial units in the country. Amongst various industries, textile industry is one of the largest and oldest industries in India. Our country is the largest cotton and jute producer in the world and has second largest textile manufacturing capacity globally. The industry includes wide variety of fibers ranging from natural fibers like cotton, jute, silk, etc. to synthetic or man-made fibers including polyester, nylon. But as the demand for textile products is increasing, textile mills and the waste generated by them are increasing proportionally, causing a major problem of pollution in the world. High volumes of water are used throughout the operations of textile industry, starting from washing of fibres to bleaching, dyeing and washing of finished products. Of all the steps involved in textiles processing, wet processing utilizes the highest volume of wastewater.
Though textile processing is responsible for generating many waste streams, including liquid, gaseous and solid wastes but the main environmental problem associated with textile industry is water body pollution which is caused by the discharge of untreated effluents. According to World Bank, it is estimated that 17 to 20 percent of industrial water pollution comes from textile dyeing and finishing treatment given to fabric.
As fresh water resources are depleting at a very fast rate so farmers are looking for alternate sources of irrigation. Therefore they have started utilizing these effluents as alternate source for irrigating their agricultural farms and fields. Though it has tried to sort out the problem of water supply but this has also led to addition of manurial ingredients and plant nutrients along with water in excessive amounts. This has resulted in the contamination of different environmental components which is responsible for deterioration of quality of life of not only human beings but other forms of life also. Though it is well evident that any kind of disturbance to the ecosystem can lead to many problems but following are few highlights of the impact of effluents from textile industry on various environmental components including soil, crops and water bodies which should be kept in mind while looking forward for solution of treatment of these effluents before their discharge.
Impact of Textile Effluents on Water Bodies and Aquatic Life
It has been found that for an average sized textile mill which is having a production of about 8000 kg of fabric per day, daily water consumption is about 1.6 million liters. Out of the total, 16% of water is consumed in dyeing while 8% of it is used in printing. Depending on the type of dyes used, specific water consumption for dyeing varies from 30 - 50 liters per kg of cloth. Many chemicals used in the textile industry cause environmental and health problems. The chemicals used in the textile industry include sodium hydroxide, sodium oxychloride, sodium bicarbonate, sulphuric acid, hydrogen peroxide, bleaching powder, dyes, mordants and many more which add to the load of contaminants in the fresh water sources. The effluent from the industry including oily scum and colloidal matter along with colors increases the turbidity. It also results in foul smell and bad appearance to the water which is characterized by high BOD and COD values of water. It can cause physiological and biochemical changes in aquatic organisms. Temperature of water is an important parameter for the survival and growth of aquatic life. Ideally water temperature should be ranged between 22-25°C and even short term temperature fluctuations in streams near the textile and dyeing industries can lead to death of fish. It is also possible that fish eggs don't hatch at all which may lead to vanishing of fish population completely from that area. The effluent addition also hinders the process of self purification of water. Hence before disposal of these effluents, it is very important to treat them properly.
Impact of Textile Effluents on Soil Health
When the untreated effluents reach the agricultural fields, it clogs the pores of the soil which can result in the loss of soil productivity. The texture of soil also gets hardened which prevents the penetration of roots. Continuous addition of effluents can also lead to change in the pH of the soil which can make it either acidic or alkaline. Strongly acidic or highly alkaline soils results in poor growing conditions for micro organisms, which results in reduction of biological oxidation of organic matter.
It has also been revealed by studies carried out by Nema et al (1990) that discharge of effluents in the fields leads to high build up of sodium (289.5 mg/ 100g) and increased content of available potassium (308.2 kg/ ha) which is much higher than their permissible limits. This can also lead to increase of water soluble salts, organic matter, Ca, Mg, NH4, N and P content of soil which adversely affects the soil health.
Impact of Textile Effluents on Crops
Irrigation of agricultural fields with textile effluents has adversely affected the soil fertility as well as plant growth. High concentration of dissolved solids present in untreated effluents affects plant growth due to reduced levels of dissolved oxygen. It has also affected dry matter production along with reduction in chlorophyll content of the plants. This reduction has been attributed to the increase in the levels of abscissic acid (ABA) which accelerates degradation of chlorophyll.
The studies carried out by Ivy et al (2015) on impact of industrial effluents on germination and early growth of agricultural crops viz. green gram, mustard and jute revealed that all the growth parameters of the selected agricultural crops showed negative trend in case of textile and dyeing effluent. Moreover jute seedlings didn't survive after treatment with textile and dyeing effluents. Similar results related to effect of different concentrations of textile effluents on soybean crop were found by Ravi et al (2014).
It has also been found that due to continuous addition of effluents to the agricultural fields, high concentrations of NPK get added to the soil which ultimately reach to the growing crops in excessive amounts. These excess N, P, K result in over-stimulation and extreme growth which attracts pests, delays ripeness or decrease the excellence of the crop. Therefore it is utmost important to treat the effluents before using it for irrigation purposes.
As population is growing at alarming rate, it is imperative to increase the production of food grains to meet the increasing needs. While the fresh water resources are limited, which are declining at a very fast pace, the usage of waste water (in the form of textile/ industrial effluents) for raising the crops is an attractive choice. But as these effluents are loaded with excessive amount of toxic chemicals along with essential nutrients for the crops, it may pose a threat to all forms of life on the earth along with disturbance to the ecosystem. To minimize the toxicity of these effluents and utilize them for irrigation purpose, the effluents should be treated using suitable strategies like chemical precipitation, coagulation, adsorption, microbial degradation etc., which may reduce the contaminants level to acceptable limits. This will not only help to utilize the limited available resources but also maintain the ecosystem integrity.
1. Ivy, N., Hossain, M. K. and Hossain, Md. L., 2015. Effects of industrial effluents on germination and early growth of selected agricultural crops. Journal of Agronomy, 14: 43-48.
2. Nema, P., Rathore, S.S. and Nema, H.S., 1990. Effect of textile effluent seepage on water quality and soil fertility. Trans ISDT, 15, 9-16.
3. Ravi, D., R. Parthasarathy, V. Vijayabharathi and S. Suresh, 2014. Effect of textile dye effluent on soybean crop. J. Pharmaceut. Chem. Biol. Sci., 2: 111-117.
About Author / Additional Info:
Working as Scientist at IARI, New Delhi