Clothing is an essential part of daily human life worldwide, but rarely do we think about how our clothes are actually made. Before fabric is sewn into the sweaters, silk blouses, and jeans that we wear, the fabric must be dyed, the process for which is often outsourced to developing countries and then to rural communities. The process of dyeing clothes most often occurs in small communities crippled with environmental problems due to the high levels of chemicals in the dyes. The problem is that once the fabrics are dyed, the waste dye is dumped back into the community’s water source, or thrown directly onto the land where it can seep into the groundwater that feeds the local water systems. Many of the residents in these communities are very poor and forced to use contaminated water for their daily needs. To help conquer this problem, I am developing a way to help people in textile dyeing communities clean their contaminated water with very affordable materials that can easily be found in and around their homes—hydrogen peroxide, iron scrap, acid, sand, and sunlight. The form of treatment I use is called photo-Fenton oxidation and sand filtration, which has been shown by many laboratories throughout the world to be an affordable, efficient method of decolorizing dye wastewater.
India is the second-largest global producer of silk employing over one million peasant families, and the majority of silk dyeing is accomplished in peasant homes within small villages. During a trip to India in 2010, I visited the town of Chintamani to observe small-scale silk dyeing businesses owned and operated by local families. While there, the families asked if I might think of a way to help them clean their dye wastewater. Inspired by their request, I am developing a mobile water treatment unit that uses photo-Fenton oxidation and sand filtration to remove the color and the most dangerous chemicals from dye wastewater. Specifically, I am building a demonstration-scale system made of rusty metal, which I will build this summer. If this is as successful as proven in the laboratory, I intend to replicate it in other rural dyeing communities throughout the world, including Morocco, Mexico, and Turkey, ensuring thousands of people obtain cleaner and affordable water.
Methodology and Data Source
1. Container (Reactor) Construction
The average homespun silk dyer in Chintamani makes 80-liter batches of dye at very strong concentrations; thus, the dye wastewater must be poured into shallow containers to ensure sun penetration and allow the oxidation chemical reaction to occur. This container, also called a reactor, is made from rusty scrap iron, which can be easily found in markets, dumps and ditches worldwide.
2. Photo-Fenton Oxidation Process and Sand Filtration
To clean the dye wastewater, first household acid is added to the wastewater, then pharmacy-grade hydrogen peroxide is added to solution, which is widely available throughout the developing world, and then the solution is poured into the rusty metal shallow container. The liquid is left to react and then it is poured through a simple sand filter to separate any solids from the clean water. The filtered water has been shown to be color free and reusable for the next dye process.
In order to improve the quality of local water sources, the residents of the dyeing communities must learn about the reaction and filtration technique. During my trip to Chintamani in 2014, I will produce an educational video in the local language that can be streamed on portable devices. The video will contain five lessons: how to make a sustainable oxidation reactor; what is the photo-Fenton oxidation process; what makes the process work; exact quantities of chemicals and time requirements; and clean water as a health initiative for families. I also hope to introduce the reactor and the videos to the Central Silk Board and the local silk farming research center, the Central Silk Technological Research Institute in Bangalore, to discuss options for the future of wastewater treatment.
Significance of Project
The need to provide rural textile communities with an effective and low-cost method to clean dye wastewater is tremendous— I personally observed the unsustainable disposal methods currently practiced in Chintamani and was shocked to see wastewater streaming through the yards of houses where children were playing and animals were grazing. If successful, the photo-Fenton oxidation process will help to clean dye wastewater from textile industries all over the world, ultimately improving the health and quality of life for millions of people. Furthermore, the low-cost and simplicity of the photo-Fenton oxidation reactors makes it possible for residents to implement this system quickly and easily in their own communities. Once the process is perfected for the small-scale dye units, there is great potential to scale it up for larger units and commercial applications.
Findings and other relevant information
My preliminary test results show a significant reduction in color and chemical levels after photo-Fenton oxidation, with even more promising results after running the decolorized wastewater through a sand filter. However, the true challenge is implementing the project in Chintamani—potential obstacles include reactor durability, project scale, and language and other cultural barriers. To overcome these, the Karnataka State Pollution Control Board has agreed to help me communicate with the region’s villagers in a way that is respectful and acclimated to local culture. The villagers, who are currently discarding their colored wastewater directly onto the land and streams behind their homes, have shown the greatest interest in the project and the most willingness to work with me to build a pilot project to improve their water quality.