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 Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung

nachricht Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>