Green buildings incorporate environment-friendly measures from the design, construction, use, and maintenance. Some green approaches include using biodegradable or recyclable construction materials and renewable energy sources. Yet water use, especially during construction, tends to be overlooked.
Water is a vital resource for construction projects. However, it can also be a source of pollution and waste without proper use. With water-efficient construction strategies, contractors can save water, protect the environment, and cut costs.
The first step to making construction sites water-efficient is to evaluate water needs. By estimating how much water the construction site will need for different purposes, project managers can plan accordingly to meet the project’s requirements. Some of the vital uses of water on construction sites include cement mixing, cleaning, and dust suppression.
From there, a project manager can determine how to measure water usage. Installing water meters at different points helps monitor how much water is being used. Meters also help identify leaks.
Next, the project manager can determine which water use avenues can be reduced, substituted, or avoided. Take temporary onsite toilets for workers, for example. Some strategies for reducing water usage include waterless urinals and high-efficiency toilets. Also, limiting washing to only necessary areas may help preserve water.
Another important aspect of water conservation at construction sites is water sources. Contractors can save on water costs by gathering rainwater. Rainwater can be used for cleaning, mixing cement, and dust suppression. It's also useful for flushing toilets. This way, clean water is used only for drinking.
Instead of letting water from cleaning go to waste, it can be gathered as greywater and reused. For example, water from basins and showers can be collected and used for flushing toilets. Greywater is also useful for dust suppression.
Concerning dust suppression, equipment, such as high-capacity hoses, wastes much water. Alternative, water-efficient solutions include atomizing or misting systems. Not only do they use minimal water, but they are also more effective at dust suppression.
Fly ash may also be used instead of cement where appropriate. Fly ash requires less water than cement. In addition to being environment friendly due to its low embodied energy (LEE), meaning less processing energy requirements, it also provides better workability. According to the Federal Highway Administration, 20 percent of fly ash in concrete can reduce water demand by up to 10 percent.
Another area contractors can consider for water efficiency is curing – applying water to freshly made concrete to maintain proper moisture and temperature, preventing cracking and shrinking due to rapid evaporation. Water is essential for curing. Some strategies for ensuring that construction workers use only necessary amounts of water include drip curing.
Drip curing is based on drip irrigation. It applies water directly at the required location, minimizing wastage. Covering the curing surface with moist canvas reduces water loss while maintaining the optimum temperature. Another water-efficient curing method is membrane curing, which uses moist curing, meaning less water is used.
Construction is not particularly water-intensive. Often, it’s about inefficient water use. The key to conserving water at construction sites is planning. Some contractors recycle water, others reuse water, and some reduce the need for water by eliminating unnecessary avenues for water use. Others even time water-heavy construction projects, like concrete mixing, to coincide with rainy seasons so they can harvest rainwater.
