PNW 98 Session - Full Abstracts
Full Abstract
1) Contact Author: Margaret McCauley
2) Institution:University of Washington, College of Forest Resources
3) Mailing Address: 423 West Mercer, 1009 NE Pacific St, Seattle, WA 98105
4) Phone #:206-934-5233
5) Email: mccauley@u.washington.edu
6) Presenter: Margaret McCauley
7) Paper or Poster: poster
8) Equipment needs other than standard slide and overhead projector:
9) Contributed session 1st choice:Functional
10) Contributed session 2nd choice:Bioassessment
11) Do you want your oral or poster presentation judged for a student award (yes or no)?: Yes
12) Would you like to be a judge for Student Awards (yes or no)?:No
13) Keywords:constructed, wetlands, wastewater
14) Authors:
15) Affiliation/institution:
(1) University of Washington, College of Forest Resources, Ecosystems,
Horticulture, & Conservation Division
16) Abstract Title:
The Role of Vegetation in Constructed Wetlands for Wastewater Treatment
17) Abstract Text:
The City of Stanwood, Washington has set up a pilot project to
establish whether wetlands treatment is a feasible option for their
municipal wastewater stream. The treatment facility’s inflow is split
among an aerated lagoon, which receives 92% of the inflow, four
constructed wetland cells which receive 4% of the inflow, and a wetland
which grew in a disused lagoon when the water level was dropped to one
foot in depth, which also receives 4% of the inflow. I propose to
compare the treatment efficiencies of the three systems (constructed
wetland, volunteer wetland, and lagoon), and determine the role of
vegetation in any differences that may exist.
The treatment efficiencies will be determined by the traditional
wastewater parameters of biological oxygen demand (BOD), total suspended
solids (TSS), and nutrient removal, specifically nitrate and phosphate.
I will compare these numbers to the plant density, species, and height.
If the water quality data is available, I will also include a comparison
of the wet meadow and marsh communities into which each constructed
wetland cell has been divided. Greenhouse comparisons of specific aspects
of the system will help me test trends in my field results in a
statistical manner.
It is expected that the use of vegetation will enhance nutrient
removal during the growing season, as nitrogen and phosphorus are
incorporated into plant tissue. The physical structure of vegetation is
expected to play two roles: first slowing the inflow water, causing
settling out of solids, and second, creating substrate for microbes that
will degrade the organic matter, reduce BOD, and volatilize nitrogen.
There are many opinions about what plants are most effective for these
purposes; this project will examine whether there are any significant
differences between using a controlled species composition and a
collection of volunteer wetland species.
18) Comments/Requests: