Adam Abdelkhalek – Environmental Stewardship and Urban Infrastructure

One of the alternative solutions to wastewater treatments that are widely used nowadays are the constructed wetlands. These wetlands are shallow pools developed specifically for storm or waste water treatment that create growing conditions suitable for wetland plants. They are great alternatives to remove contaminants from wastewater, and have been used for decades now.
Constructed wetlands have the same properties as natural wetlands, and are designed to provide water quality benefits through various process that will ultimately minimize pollution prior to the water entry to streams. They also act as biofilters, and remove sediments and pollutants such as heavy metals from the water, and can even serve as wildlife habitat even though that is outside the scope of its main purposes.

There are 2 types of constructed wetlands:

Surface Flow Systems (Free water surface):

A surface flow constructed wetland have standing water at the surface, and can be used as a tertiary treatment facility at a wastewater treatment plant. This system consist of a basin full of water, and macrophytes roots planted that emerge at the water surface. The effluent water is treated as it flows over the soil, and organic material is removed through microbial degradation.

The figure below shows a surface flow constructed wetland.

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Subsurface Flow Systems:

Subsurface systems have no visible standing water, and are designed so that the wastewater flows through a gravel substrate beneath the surface vegetation.The wastewater passes through a sand medium on which plants are rooted. A gravel medium (generally limestone or volcanic rock ) can be used as well and is mainly deployed in horizontal flow systems though it does not work as efficiently as sand.
In the vertical flow constructed wetland, the effluent moves vertically from the planted layer down through the substrate and out. In the horizontal flow CW the effluent moves horizontally, parallel to the surface.

The figure below shows a subsurface flow constructed wetland.

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Constructed wetlands are then extremely important to wastewater and play a big role in gray water systems. Just like other major systems, they include all components necessary to the efficient treatment of gray water such as: collection of water, treatment, disinfection, and distribution.

References:

http://www.ces.uoguelph.ca/water/NCR/ConstructedWetlands.pdf

https://www.epa.gov/wetlands/constructed-wetlands

http://www.gov.pe.ca/photos/original/eef_wildlife_p1.pdf

The IDP was first used in the early 1990s, by Canada’s C-2000 program (program supporting advanced, energy-efficient commercial building design) and IDEAS Challenge competition (multi-unit residential buildings challenge) to describe a more holistic approach to building design. In profesional practice, IDP has a significant impact on the makeup and role-playing of the initial design team. The client takes a more active role than usual, the architect becomes a team leader rather than the sole form-giver, and the structural, mechanical and electrical engineers take on active roles at early design stages. The team includes an energy specialist (simulator) and possibly a bio-climatic engineer. Depending on the nature of the project, a series of additional consultants may also join the project team from the outset.

Some of the key advantages of the IDP are cited below:

Goal-driven with the primary goal being sustainability, but with explicit subsidiary goals, objectives and targets set as a means to get there.
Facilitated by someone whose primary role is not to produce the building design or parts of it, but to be accountable for the process of design.
Structured to deal with issues and decisions in the right order, to avoid locking in bad performance by making non-reversible decisions with incomplete input or information.
Clear decision-making for a clearly understood methodology for making decisions and resolving critical conflicts.
Inclusive—everyone, from the owner to the operator, has something critical to contribute to the design and everyone must be heard.
Collaborative so that the architect is not simply the form-giver, but more the leader of a broader team collaboration with additional active roles earlier in the process.
Holistic or systemic thinking with the intent of producing something where the whole is greater than the sum of the parts, and which may even be more economic.
Whole-building budget setting—allows financial trade-offs, so money is spent where it is most beneficial when a holistic solution is found.

Below is a graphic representation of the IDP Process:

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References:

http://www.nrcan.gc.ca/energy/efficiency/buildings/eenb/integrated-design-process/4047

http://iisbe.org/down/gbc2005/Other_presentations/IDP_overview.pdf

http://www.infrastructure.alberta.ca/content/doctype486/production/leed_pd_appendix_7a.pdf

Author: Adam Abdelkhalek

Constructed Wetlands I

IDP: The Integrated Design Process