The Green Matrix
Due to its very nature of activity the Construction sector, has been among the most polluting sectors degrading the environment. Like mining it leaves a permanent trail of environmental destruction. Fortunately it is also among the best placed of all sectors to reverse rapid degradation of Mother Earth. And that awareness is evident in the new trend of eco friendly construction across the world. The entire construction industry -- from materials to methods to equipment, have now acquired a Green hue. And everybody wants a rub of that Green!
The new buzz word in our sector is 'Eco-friendly' construction or Green Buildings. This is because there is now a paradigm shift in the way the concept of a building is defined, which is in an environmental context. The environmental concept of a building now encompasses 'embodied energy' in the building or its carbon footprint in terms of materials and construction processes. On occupancy and 'in use,' the next parameters are energy efficiency, water conservation, and its air quality. And the underlying denominator is the lifecycle of a structure, which means at the end of its lifecycle even in demolition it should be environmentally safe where in all materials can be recovered and recycled back into the construction cycle. It is important to recycle construction materials because buildings account for 20 per cent of global greenhouse gas emissions, that's 9 billion tons of carbon dioxide each year. Concrete, aluminum, and steel are among the materials with the highest embodied energy content and are also responsible for large quantities of CO2 emissions – for example, 9.8 million tons of CO2 are generated from the production of 76 million tons of finished concrete in the US. Existing building practices and technologies are inefficient and generate high levels of greenhouse gas pollution. For example, by using existing technologies, the EU could reduce emissions from the building sector by about 400 million tons of CO2. That’s more than the total EU greenhouse gas reduction commitment under the Kyoto accord.
Environmental Impact Assessment, or EIA, is the new Green Matrix to calculate the probable impact that a proposed project may have on the natural environment. A team of researchers from the Polytechnic University of Catalonia (UPC), in Spain has developed a method to evaluate the probable environmental impacts caused by a proposed project well in advance. With just the project data, the new method can calculate and predict up to 37 environmental impacts, which could help improve environmental management in the construction processes, the authors claim.
Although EIA is now a standard process in most projects at the initial concept and design stage, the construction company is often caught amidst conflicting priorities which take into account facade, console, ease of construction, maintenance expenditures, principal costs, etc. Amidst all these viability variables environmental impact is a very supplementary variable. Also, a few site control measures for the duration of construction can lessen the environmental impacts and also keep the neighbourhood at ease from annoyance at the construction site. Most importantly it is possible to amalgamate environmental considerations in the design process itself without incurring additional costs.
Reuse, Recycle, Redesign
In so far as Green Sustainable construction goes it is most important to follow the three R’s of resource conservation. The greatest opportunity to recycle materials is in those elements that change the most often, such as partitions, finishes, furniture, and supplies. These also have the most opportunity to be redesigned based on available technology and sources for new materials. Permanent partitions and fixtures should be assembled in such a fashion that they are easily disassembled for reuse or recycling. Finishes should be minimal, natural and nontoxic. Recycled content will be the only ingredient in 95 per cent of all replacement materials on the site.
Another major area of recycling materials is the construction and demolition (C&D) materials found in abundance at any construction, renovation, or demolition site. The most common materials found are concrete, wood, drywall, asphalt shingles, asphalt pavement, metal and cardboard. These materials typically make up 70 to 95 per cent of the discarded material at a residential or commercial site. They are often discarded but are actually valuable commodities that can be recycled into new products or used in many new ways. Perceived as waste, disposal of C&D materials is often viewed as simply part of the cost of doing business, and recycling and reusing these materials are sometimes overlooked as management options. Recycling can benefit a construction business’s bottom line, and it benefits the environment.
But the real breakthrough in recyclable materials will come from nanotechnology. Given enough time nanotech will spawn hybrid construction materials of all types which will have a longer lifespan and at end of which they can be recyclable. And generically it will be Phase Changing Materials where nanotech will give such game changing breakthroughs.
Buildings account for over half of global energy use and most of that energy is wasted through poor design and wasteful practices. Buildings account for 30‐40 per cent of global energy use, and construction/demolition activities push this to over half of global energy use. Traditionally most of the domestic energy consumption is supplied by power utilities which depend on power generation from fossil fuels, mostly coal and oil. For Green Sustainable construction it is imperative to shift to renewable energy like solar, wind and hydel power. Solar energy is the most promising, also most viable commercially at the individual household level. But currently the biggest stumbling block here is storage cell technology. But this problem can be overcome by having a common distribution grid at the local level where all units are plugged into and can provide their excess power to others who need more power, where a household is charged for surplus power and those with surplus power can sell it on the grid. All it needs is a sophisticated metering and billing on a commercial billing basis. Photovoltaic technologies were costly in the beginning but are now available at half their original cost. Similarly Hydrogen powered fuel cells are now available in increasingly smaller units to meet myriad applications. Geothermal has improved at a slower rate, being dependent on qualified technicians. In India solar power is growing by leaps and bounds but the initial costs of installing the solar panel still remains costly in India. However using existing appropriate technology came make it more affordable.
"Out of the 100,000 MW solar power, 40,000 MW will be in the form of rooftop solar power, which translates fully into the building stock, which directly relates to green buildings. 26 states and UTs have established guidelines for rooftop solar power which will definitely add to the overall effort of enabling green building. We are also making efforts to incorporate green architecture into civil engineering and architecture based courses,” says Dr A K Tripathi, Director, Ministry of New and Renewable Energy, Government of India.
An important parameter of Green Buildings is that for a facility to be sustainable, the water use for the building and site should not exceed the budget afforded by its “footprint” share of the watershed. This respects the balance of natural systems. Borrowing water from another site or watershed violates this balance. This is adequate water for all building processes. On site water
treatment technologies can provide drinking water if needed. Systems to store, treat and distribute water will be required. Seasonal rainfall and future capacity requirements should be taken into account to size the system. Like other utilities of waste recycling, and power distribution, this approach becomes financially viable only at the community or institutional level as opposed to the household level.
Zero Discharge Habitats
All the above variables -- recyclable materials, renewable energy, water recycling -- add up to a Zero Discharge Habitat. In this context another variable of emergent importance is the Landscaping of the project site. Landscaping will soon assume a new significance, about being ecological and sustainable. This begins from digging into the top soil to build foundation of the structure. The excavated soil can be reused for landscaping the open spaces within. Its lamentable that currently most of that excavated soil is subtracted from the net amount of soil at site and sold by contractors elsewhere. This degrades the local ecology irreversibly, and especially more so for regions rich in bio-divesity. Ecosspheres take a long time to regrow. It makes more sense to preserve them on site and adapt the construction design in consequence. There are few examples of constructions which have successfully managed to preserve trees and built around them, or even incorporated them within the structure.
At the design stage itself the project should be in synch with the bio-diversity and local ecosphere where all project parameters should be in consonance with the environment. This also necessarily includes local groundwater resources and local sourcing of construction materials. Waste recycling is another parameter to be kept in synch with the environment. As per the latest definitions all these parameters have to add up to a 'Zero Discharge' quotient. Today construction of any structure has to take into account its environmental impact and calculate it at the design and construction stage itself.
To ensure zero discharge habitats, Waste Recycling is the final module to be put in place. The biggest breakthrough here will come from biotechnology and nanotechnology to recycle organic waste, which constitutes a major volume of urban waste. There are different types of Sewage Treatment Plants (STP). The most common is promotion of microorganisms to eat or eliminate undesired elements of wastewater. Activated sludge uses dissolved oxygen to promote aerobic processes that remove organic wastes. A variant on this type combines activated sludge with a membrane separation system. Biological aerated filters work by using a filer medium (either suspended in solution or attached to a layer of gravel at the bottom of the tank) to achieve the removal of organics and denitrification. Filter beds put the sewage in a tank over a bed of coke or limestone chips that support the growth of microorganisms feeding on the organic matter in the sewage. These microorganisms, in turn, are fed upon by worms and the like. Rotating disks work by placing the active component on the face of a disk. It's then slowly rotated through the tank, constantly re-exposing it to the open air and providing the extra oxygen the active microorganisms need to work.
The single most important parameter for proper management of waste disposal is that it should be eco friendly. The most basic technologies used for sewage treatment and recycle in India are Activated Sludge Process (ASP), Membrane Bio-Reactor (MBR), Fluidized Bed Bio-reactor (FBR), and Sequential Batch Reactors (SBR). Most waste treatment plants are seen as an additional expense. Few realize that waste treatment can be turned into a new value stream that can reap profits. The urban waste generated can be used as fuel feedstock in many industries. India has a lot of potential for recovery and recycle of municipal waste. Some of the recovery methods used in India are as follows: Waste-to-energy technology which include refuse derived fuel (RDF), incineration, and anaerobic digestion, and composting for bio wastes. Basically urban waste can be categorised into biodegradable waste and non-biodegradable waste. Biodegradable waste can be composted or anaerobically digested to produce soil improvers and renewable fuels.
The Green movement has already metamorphosed our concept of a house into a community. Out of necessity the concept of Green Building has to include community clusters. In this context Green construction is decisively shaping the future urban village, as opposed to megapolises and metropolises. Agglomeration of Urban Clusters which are small enough and manageable to keep them green. Here urban planning assumes a critical role.
When the Indian Green Building Council (IGBC) was established in 2001, one green building with a floor area of 1,858 m2 marked the beginning of green building in the country. Today, more than 2,100 IGBC-certified green buildings occupy almost 140 million m2 (IGBC). The IGBC has 1,413 members and around 20,000 professionals in the construction sector have been trained in its rating system. In 2011, the total floor area of green buildings in India was higher than in Brazil, Canada, China and South Korea, although green buildings account for a small proportion of the total building stock and a small share of the Indian construction market.
According to industry analysts, the market for green building in India was projected to grow three-fold from $10 billion in 2011 to $30 billion in 2014.