Demand-side regulations like mandating a certain percentage of building materials from fly ash in the building by-laws of cities could go a long way in increasing the utilisation of fly ash.
In my previous column (bit.ly/2J5PS7N), I discussed how the draft notification issued by the ministry of environment, forest & climate change (MoEF&CC) on utilisation of fly ash for brick making is a non-starter. I ended the column thus: ‘So, how should we design a law that allows for maximum utilization of fly ash, significantly reduces the consumption of clay and the air pollution from fired clay brick kilns and yet meets the requirements of the construction industry?’ In this column, I will put out the essential components of a legal framework that meets these requirements.
Maximising utilisation of fly ash
For the past 20 years, the environment ministry has promoted utilisation of fly ash bricks by mandating manufacture of fly ash bricks within a certain distance of thermal power plants (TPPs). In the draft notification, the distance has been fixed as 300 km. The implicit assumption here is that within 300 km of a TPP there is a perfect match between the availability of fly ash and demand for bricks. This is obviously incorrect. The availability of fly ash in and around TPP clusters like Korba in Chhattisgarh and Singrauli in Madhya Pradesh far outweighs the demand for bricks. In contrast, there is not enough fly ash to meet the demand of the brick industry in Delhi-NCR.
This variation in demand and supply in different parts of the country is the reason why a blanket approach to fly ash utilisation has failed so far. To address this, we should adopt a regional approach to fly ash regulation. That is, regulation should be tailored depending on the availability of fly ash and the demand for the material in a region. In general, regions with high fly ash availability should be mandated to produce more of their building materials from fly ash and vice versa.
But, mandating the manufacture of fly ash bricks is not sufficient. There should also be demand for it. Demand can be created by putting in place demand-side regulations and by promoting use of fly ash bricks and other products.
Demand-side regulations like mandating a certain percentage of building materials from fly ash in the building by-laws of cities could go a long way in increasing the utilisation of fly ash. But the most important thing required for generating demand is quality control and certification of fly ash products.
There is a serious concern with the quality of fly ash bricks. Most of the people who commented on my previous column complained about the poor quality of fly ash bricks. Many suggested that instead of only bricks, other fly ash products like AAC blocks, fly ash concrete blocks, FaL-G blocks, fly ash foam concrete, etc, should be promoted. I agree with these suggestions. If we need to promote utilisation of fly ash, we should promote a wide variety of fly ash products and not just bricks. For this, we need promotion and certification programmes to enhance the acceptability of fly ash products in the market.
Lastly, there has to be credible deterrence for non-compliance for TPPs. TPPs have flouted the fly ash notification for two decades because they know that the penalty is small. Any new law must increase the penalty for non-compliance and set up a transparent system for supply of fly ash to different users. A regional-level online portal for compliance assurance can be established to improve the enforcement of the law.
Reducing clay consumption and pollution
The environmental footprint of fired clay bricks can be significantly reduced by finding an alternate source of clay, changing the brick kiln technology and by producing different kinds of fired clay bricks. Clay can be sourced sustainably from desilting of rivers, lakes, ponds, ports, reservoirs, etc. In West Bengal, clay is sourced in many districts from desilting of floodplains. It is estimated that in Howrah, Hooghly and West Medinipur, close to 2 billion bricks are produced annually from desilting of floodplains after high tide. Similarly, silt from desilting of tanks in and around Bengaluru is now becoming an important source of clay for brick manufacturers. Clay can also be commercially mined from large clay deposits, as is being done in major brick producing countries like Vietnam and China.
The fact is that we can get enough clay from sources other than agricultural land to meet the demand for clay bricks. What we need for this is a proper assessment of the availability of clay in different parts of the country followed by regulations on desilting and clay-mining.
We can also reduce clay-mining by making different varieties of fired clay bricks. In Maharashtra, Andhra Pradesh and Telangana, clay is mixed with fly ash or waste such as lime slurry to make bricks. Similarly, instead of making solid bricks, hollow or perforated bricks can be made which reduces clay requirements by 20–30%. Wienerberger, the world’s largest producer of clay bricks, produces hollow clay blocks—which require 60% less clay than conventional bricks—in its Bengaluru plant. Hollow and perforated bricks and blocks have the added advantage of better insulation properties and lower energy demand for heating and cooling in buildings.
We can reduce pollution from brick kilns by using better technology. Currently, most Indian kilns use outdated tech such as clamps and fixed chimney bull’s trench kiln (FCBTK). These are highly inefficient and polluting and should be replaced with zigzag technology or the more advanced vertical shaft brick kiln or tunnel kiln to significantly reduce coal consumption and air emissions. In nutshell, there is a large scope to reduce the ecological footprint of fired clay bricks that we have not even tried.
It is clear that maximising fly ash utilisation and reducing the environmental impacts of fired clay bricks require much more than just a simple law that bans fired clay bricks. It requires a holistic view of the brick sector, from sourcing of raw materials and production of bricks and building materials to sales and promotion of alternative building materials. It requires a vision on how we will meet the material requirements of the building sector in a climate-constrained world. For this, we need National and State Brick Missions (and many laws) that can transform the brick sector by facilitating large-scale adoption of cleaner technologies and by bringing innovation in the building material sector. Bricks are an age-old industry and the backbone of the construction sector. The continuing use of inefficient and polluting technologies as well as inadequate push for innovative building materials has kept the brick sector stuck in the 20th century. It is time it moved to the 21st century.
(Writer is Deputy director general,
Centre for Science and Environment