February 2014, Vol. 26, No.2


Agricultural drainage with basic filtration improves water quality

Ponding water on agricultural fields poses a problem both for farmers and scientists. Blind inlets provide a tool for farmers to eliminate this water from their fields and for scientists to manage agricultural pollutants in the Lake Erie watershed, according to an Agricultural Research Service (ARS) news release. 

Because prairie potholes in crop fields are prone to collecting water that has no natural outlet, farmers often install tile risers to drain the excess. Risers are perforated vertical pipes that extend 0.3 m (1 ft) or more above the soil and connect directly to subsurface tile drainage networks. Water is discharged by the subsurface networks into the nearest field ditch without filtration or processing. Agricultural pollutants drained from the potholes in northeast Indiana’s St. Joseph River watershed eventually reach Lake Erie, the news release says. 

ARS scientist Doug Smith and others developed blind inlet systems to facilitate filtered field drainage. The systems are constructed by digging a 0.9-m (3-ft) square area at the lowest point of each pothole and lining the area with layers of gravel, tile lines, and other drainage materials, the news release says.   

Smith studied quality of the drainage water from tile risers and the blind inlets. Water samples from risers had the highest levels of total phosphorus and almost all samples had higher levels of sediment, soluble phosphorus, total phosphorus, and nitrogen than those from inlets. On average, samples from inlets had 78% lower phosphorus loads and 79% lower sediment loads than those samples from risers, the news release says. 



Groundwater under Chesapeake Bay boasts an ancient history

Salty groundwater lying under the Chesapeake Bay has an ancient history, according to a study by U.S. Geological Survey (USGS) scientists. More than 1000 m (0.6 mi) under the bay lies a body of seawater, which is twice as salty as modern seawater. This ancient water dates back 100 to 145 million years, according to a USGS news release.

A remnant from the Early Cretaceous North Atlantic Sea, the water was preserved underground when a massive comet or meteorite struck the area and created the Chesapeake Bay about 35 million years ago, the news release says.

“This study gives us confidence that we are working directly with seawater that dates far back in Earth’s history,” as said in the release by Jerad Bales, acting USGS associate director for water. “The study also has heightened our understanding of the geologic context of the Chesapeake Bay region as it relates to improving our understanding of hydrology in the region.”

The study has been published in the Nov. 14 issue of the journal, Nature.



Space station of the sea may start explorations by 2016 

The SeaOrbiter, a mobile international oceanic station, could begin exploring the open sea and abyss as early as 2016.  

The 12-level station would provide an underwater habitat enabling 18 crew members to live, explore, and broadcast their adventures and research through on-board communications systems. Constructed from recycled aluminum, the approximately 454-Mg (500-ton) station has a lifespan of about 15 years and will include a small propulsion system. Some inner spaces will be pressurized to allow divers to undertake daily missions. 

The “eye” of the vessel is designed to measure a total 58 m (190 ft) tall with 18 m (59 ft) reaching above the surface of the ocean. It will support the crow’s nest and communications systems. Currently a 90-day, crowd-funding campaign is being held to finance the construction of the eye of the vessel. Construction is scheduled to start in spring 2014, the news release says. 

Jacques Rougerie brought together sea and space experts to design and build the station. The first underwater missions are planned for 2016 in the Mediterranean, the news release says. 


Hydrogasification system uses biosolids to produce energy

In November, the University of California, Riverside, and the California Energy Commission (Sacramento, Calif.) unveiled a new system that uses biomass feedstock to produce substituted natural gas.
The university’s College of Engineering Center for Environmental Research and Technology (CE-CERT) Advanced Thermochemical Research Laboratory has been developing systems that thermochemically convert biomass into energy, according to a university fact sheet.

The laboratory has been working for more than a decade to develop the steam hydrogasification reaction process demonstration unit (PDU), which uses steam and recycled hydrogen to transform carbon-based materials into fuel. It is designed to be 12% more efficient and can process material 10 times faster than conventional dry gasification systems, according to a university news release.
The PDU does not require oxygen or drying of feedstock and is able to use municipal solid waste or biosolids from water resource recovery facilities to produce fuel, the fact sheet says. The system is designed to maintain low operating temperatures and pressures, allowing it to operate efficiently at a low cost, the fact sheet says.

The laboratory also houses two other process systems including a feedstock pretreatment unit and water gas shift reactor that can process output from the PDU into substituted natural gas, the fact sheet says.
CE-CERT is using a PDU scale reactor to demonstrate its continuous operation at the fluidized bed reactor and to design the pilot-plant-sscale process. Researchers expect to build a commercial-scale unit within 3 years, the fact sheet says.