Environmental Engineering: Bringing Nature to Concrete Jungles

The expansion of the world’s population and the worsening effects of urban sprawl has brought environmental engineering into the spotlight. The ultimate objective of this branch of engineering is to ameliorate pollution and other adverse environmental challenges and maintain public health, safety, and well-being.

An increasing amount of research and real-life examples highlight the value of balancing nature, mimicking natural processes, and using sustainable and reclaimed materials in environmental engineering. Some progressive examples have accomplished this by encouraging the re-establishment of natural environments in urban landscapes, residential complexes, buildings, and other “concrete jungles”.

But before engineering a new sustainability initiative or “greening” an existing site or facility to support the natural environment, it’s essential to take a look at the current state of environmental engineering and systems. Getting a sense of the new and up-and-coming technologies and applications can help you better understand the benefits and challenges of different environmental and sustainable engineering solutions, stay ahead of the competition, and identify the best execution plan for new projects.

The Goal of Environmental Engineering

Before digging into the nitty-gritty of environmental engineering, let’s take a quick step back to cover the basics. The overall purpose of environmental engineering is to protect public health and wellness through effective prevention, control, and remediation of environmental problems.

To this end, environmental engineers are predominantly concerned with developing sustainable solutions to remedy air and water pollution, improve our waste and sewage disposal practices, and promote healthy recycling and diversion operations.

Environmental engineering is also closely tied to the art and science of sustainable engineering, which can be applied to any engineering discipline or practice. Sustainable engineering, similar to environmental engineering, is focused on:

• Balancing social and economic values while, at the same time, preserving the health of the natural environment and reducing resource, energy, and water consumption.
• Meeting the needs of the public without jeopardizing the needs and opportunities of future generations.
• Designing buildings and systems that account for the entire product and process lifecycle as well as the global and future impacts.

Applications & Opportunities for Environmental Engineering

Designing and engineering sustainable and environmentally-sound infrastructure and systems require overcoming considerable logistical, technical, and market obstacles. It entails facing important decisions on how to best implement an environmental improvement or development project and optimize the economic, environmental, and social benefits to the maximum extent possible.

But while improving the environmental footprint and sustainability of our engineering, construction, and manufacturing practices today pose significant challenges, the opportunities for environmental engineering are endless. In fact, there’s already a breadth and depth of state-of-the-art infrastructure, systems, and processes in operation today that not only support (and even further) the principles and goals of environmental engineering, but also reduce capital and operating costs, encourage public well-being, and stimulate new markets and job growth.

We’ve compiled a list of a few cutting-edge and lucrative examples to provide a snapshot of where we are and where we’re headed in environmental engineering.

Floating Wetlands for Water Treatment

Floating wetlands are an excellent up-and-coming example of innovation in environmental engineering. Providing a highly-productive natural ecosystem and a concentrated wetland effect, floating wetlands have proven time and time again to be a high-performing, low-cost, low-maintenance (and naturally beautiful) enhancement to municipal stormwater and wastewater treatment ponds, detention basins, or plants.

Floating wetlands are man-made wetlands that can be retrofitted to residential and urban water treatment ponds in order to improve treatment effectiveness, sustainability, and cost-efficiency. When used for stormwater management and treatment in natural ponds, they can address turbidity issues, restore habitats, curtail erosion from wind and wave action, load non-source pollutants, provide nutrient hotspot mitigation (i.e.removal of nitrogen, phosphorous, TSS, etc.), improve shoreline protection, and reduce the rate of coastal erosion.

Floating wetlands are able to do this by using nature as a model through biomimicry. In other words, they’re designed to mimic the biological processes of natural floating islands in urban and/or residential settings (i.e. in man-made“concrete jungles” that disrupt the sediment flow and pollutant removal mechanisms of natural ecosystems).

Not only do floating wetlands provide anatural and sustainable sewage and water treatment solution, but they’re also made out of recycled materials. While it may sound counter-productive, many floating wetlands today are made out of plastic PET bottles, plant roots, and more than 3,000 species that work synergistically together to provide an initial raft or platform for natural processes to take charge of water treatment.

The species that contribute to the complex, extremely resilient, and highly effective ecosystem created by floating treatment wetlands are: bacteria, protozoa (grazers/predators), worms (Nematodes, Rotatoria), mollusk (mussels, snails), arthropod (crayfish), plants, and fish. They do so by facilitating biofilms, microbial activity, and symbiotic relationships that produce an active surface area, extend ecological mass-transfer, and maximize retention time.

Case studies of floating wetlands retrofitted to existing assets have proven so productive, in fact, that they can be used as bird sanctuaries, public green areas, and homes to lizards, fish, and a variety of critters. On top of that, they also carry low capital expenditures and operating expenses. Withall of its benefits, floating wetlands are a breakthrough technology in environmental engineering and a fruitful solution to beautify urban concrete jungles using repurposed recyclables.

Greening Concrete with Wastes & Byproducts

It’s predicted that concrete in the future will be designed and constructed largely using salvaged materials and waste byproducts to achieve environmental engineering goals.

Popular recycled wastes and byproducts that can be found in alternative concrete mixes today for building and road construction applications include: recycled crushed concrete, wallboard and other building demolition wastes, reclaimed tires, glass, steel, plastic, ground rubber, coal combustion byproducts, and discarded brick and marble.

Furthermore, instead of using traditional cement as an ingredient in concrete, fly ash and limestone cement can be used as a replacement. Recycled and reused asphalt pavement mixes can also be used in road construction to minimize virgin aggregate use, reduce trucking costs, and accelerate load test screening.

Coir geotextiles, which are made out of natural coconut fibers, can also be used in paved and unpaved road construction for erosion control. Coirs have also been used in the construction of buildings, railways, automobiles, ships, cars, aircraft, and even spacecraft to provide increased durability, weather resistance, soundproofing, insulation, and fire protection.

Green Buildings: A Staple of Environmental Engineering

Green buildings are a cornerstone of environmental engineering. Green buildings and their rating and certification programs—such as Leadership in Energy andEnvironmental Design (LEED), Living Building Challenge (LBC), and the WELL Building Standard—are strategically designed for efficiency.

Green buildings are rated and given utility tax breaks based on items such as energy and water efficiency; materials and labor use; the amount of local, repurposed, and organic materials; operational costs; self-sufficiency and regenerative performance; and compliance with pre- and post-construction stormwater management, erosion control, and water quality regulations.

Upholding the 5 pillars of GREEN—energy, health, materials, water, and place—is essential to score LEED points and advance environmental engineering initiatives. “LEAN” and other practices to reduce the time, resources, and effort put into a building are increasing in popularity as an effective way to achieve green certification and keep up with the flow of progress.

Green Infrastructure: Another Environmental Engineering Cornerstone

Green infrastructure (also known as green stormwater infrastructure) and low-impact development practices (LID)—including rain gardens (i.e. bioretention or bioswales), impervious area disconnection, permeable pavement, green roofs, and green walls (i.e. biowalls or living walls)—are escalating in popularity and effectiveness as a way to reduce, manage, and even treat stormwater runoff.

While native soil infiltration rate has proven to be the most important factor in reducing stormwater runoff, regional climatic differences significantly impact the performance of different green infrastructure practices. Thus, it’s critical for environmental engineers and stormwater designers to understand exactly how green infrastructure works to reduce runoff (via infiltration, evapotranspiration, groundwater flow, catch basin,etc.) and the impact of climate.

Environmental Engineering in Erosion Control

Compost blankets. Biodegradable compost blankets can typically be seen on construction sites, streambanks, and other areas with disturbed soils for both stormwater and erosion control. Compost blankets absorb rainfall to reduce sediment runoff and subsequent erosion and improve downstream water quality, habitat health, and vegetation establishment.

Coir geotextile fabrics. Coir fabrics are made of natural woven fibers extracted from the outer layer (husk) of coconuts. They prevent streambank erosion and construction soil erosion, encourage the healthy establishment of trees and forests, shield plants and grassy areas, and protect against wind and wave action.

Brush mattresses. Also known as a “livebrush mat”, a brush mattress is an effective streambank protection practice that combines live brush cuttings, bundles of sticks or other materials, and wooden stakes.

Other best management practices (BMPs) used in environmental engineering as a means of defensive (as opposed to offensive) erosion control include tree revetment systems, rootwall composite systems, and a host of other applications.

Coastal Erosion Control BMPs. Practices that follow environmental engineering principles and allow natural processes to provide shoreline/coastal erosion control include:

• Wetland, dune, rock, and barrier beach restoration
• Reef restoration (e.g. wave attenuation devices, spawning grounds, marine mattresses, etc.)
• Gabions and other specific defensive coastal erosion control BMPs

The Growing Importance of Environmental Engineering

Many countries, including the U.S. and Canada, have sent the majority of our wastes and (often contaminated) recyclables to China for decades. But due to quality and environmental issues, China is no longer accepting the imports of more than 32 (and counting) types of scraps, wastes, and recyclables.

To make matters worse, there’s currently minimal local waste diversion operations in North America and a lack of viable domestic markets for our wastes. Thus, environmental engineering and the repurposing of our consumables for sustainable engineering initiatives are expected to grow in importance, and at a significant rate. The challenge will be uniting all parties to solve the problem (including engineers, contractors, city planners, public works divisions, local diversion centers, etc.) and shift towards the development of built environments that can support local demand.

Greening the Future of the Economy

With the progression of environmental engineering, we can now create natural environments and full-blown ecosystems within the concrete jungles of our expanding residential and urban developments today.

Because of the incredible environmental impact of environmental engineering on a global scale, the future of engineering is destined to move towards establishing more sustainable environments.

As environmental engineering technologies continue to make bigger and bigger waves across various industries today, environmental and sustainable engineers (and engineers in general) will increasingly be tasked with establishing and ensuring compliance with guidelines and practices for the reduction and use of wastes and non-renewable resources. But considering the untapped opportunities in environmental engineering and their potential economic benefits, the market is ripe for the picking.