Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research Indicates Wetland Used With Batch Dosing Produces Cleanest Water From Septic Tank

20.08.2009
With approximately one-fourth of the homes in the United States utilizing a septic tank system for on-site wastewater treatment, finding better ways to protect the surrounding environment and, ultimately, residents' drinking water are essential. Now, Baylor University researchers have created and tested several new treatment systems to see if they could be part of the next generation of residential treatment systems.

Dr. Joe Yelderman, professor of geology at Baylor, and Dr. Margaret Forbes, research associate of biology at Baylor, constructed five different submerged gravel wetlands and tested the contaminant-removal ability of each wetland against different dosing systems, ranging from a continuous dose to a more rapid batch dose coming out of a septic tank. The submerged wetlands rely on the gravel and plants to remove contaminants by mirroring the pollutant removal ability of nature.

“There are a lot of places where it would be nice to build a home, but if you can't put in a septic tank because the soil can't handle a drain field, you can't build a home there unless you have some sort of alternative treatment system,” Yelderman said. “Our goal was to improve the water quality coming out of the septic tank so residents could dispose of the treated wastewater into thinner soil or places where the water table is higher. It would just provide more options to them.”

In Texas, state law requires treated wastewater from a septic tank must be disposed of in the soil, however traditional septic tanks need a certain depth of soil and a certain type of soil to meet environmental standards. Once treated wastewater – known as effluent – leaves a residential septic tank, it flows into what's called a drain field, which is an arrangement of perforated pipes that carry the effluent into the soil. In theory, the soil will further decompose the effluent, making it safer for the environment. However in many areas, the water table is either too high, which means the effluent does not have a chance to fully decompose, or the type of soil can not adequately absorb the effluent, which is the case around much of north and central Texas. The end result produces contaminants like phosphorous and nitrate entering the groundwater.

After several tests on the wetlands to see what dosing system works the best with a specific wetland, the Baylor researchers found that the wetland with gravel and plants performed better, or discharged water that was cleaner, during batch dosing when compared against more continuous dosing. Yelderman said he believes the batch system performed better because of the interaction with the air in between the dosing. When the wetland dried out and was then re-wetted, the gravel and plants oxidized the wastewater better and allowed the aerobic bacteria to better decompose the organic matter. Yelderman said this process actually stressed the plants and they did not grow as large, but they adjusted to the fluctuations and sent their roots deeper.

The results also showed that the wetlands with a certain type of gravel – an expanded shale aggregate – did not perform as well as expected, however it performed as well if not better that just using “regular” gravel. Yelderman said the results also show that the majority of the wetlands significantly reduced Biological Oxygen Demand (BOD) and successfully reduced nutrients like phosphorus and ammonia.

The research was funded by the Texas Onsite Wastewater Treatment Research Council and was completed at the Baylor Wastewater Research Program research site located at the Waco Metropolitan Area Regional Sewerage System.

Matt Pene | Newswise Science News
Further information:
http://www.baylor.edu/pr

More articles from Ecology, The Environment and Conservation:

nachricht How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

Im Focus: Hydrogen Bonds Directly Detected for the First Time

For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.

Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

Media accreditation opens for historic year at European Health Forum Gastein

16.05.2017 | Event News

 
Latest News

New approach to revolutionize the production of molecular hydrogen

22.05.2017 | Materials Sciences

Scientists enlist engineered protein to battle the MERS virus

22.05.2017 | Life Sciences

Experts explain origins of topographic relief on Earth, Mars and Titan

22.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>