Water Resources Center funds three research projects in annual grant competition

The Water Resources Center awarded funding to three research projects for 2015. The funded research projects include improving the mechanics in drinking water filtration systems, the effect of invasive mussels on the marine environment, and finding a safe balance between the economic boon of mining operations and sulfite damage to wild rice habitat.

Improving the (Bio)fouling and Mechanical Resistance of Ultrafiltration Membranes for Drinking Water Production 

Principal Investigator (PI) Santiago Romero-Vargas Castrillón will test the effectiveness of graphene oxide (GO) to strengthen the membranes used in ultrafiltration (UF) at water treatment facilities. UF is a membrane-based water separation process widely used in drinking water production. The membrane can become clogged with particles and bacteria, which decreases its effectiveness and can cause complete membrane failure. Castrillón will use GO to improve the resistance of the membrane to mechanical stresses that are common during membrane cleaning and backflushing. In addition, surface modification with antibacterial GO is expected to mitigate bacterial growth on the membrane, a phenomenon known as biofouling. “My research objective is to improve the longevity and effectiveness of ultrafiltration membranes by improving membrane mechanical and interfacial properties,” said Castrillón.

Invasive mussel shells and biogeochemistry of Minnesota lakes

Zebra and quagga mussels, also known as dreissenid mussels, have been the target of much research as scientists seek to understand the effects of dreissenid activities on the cycling of carbon (C) and the nutrients phosphorus (P) and nitrogen (N). Ted Ozersky, (WRS faculty, UMD, LLO) studies the ecological impact of dreissenid shell accumulation and shell breakdown on water resources. “We do not know how much shell there is in different systems, what this shell is made from and what its long-term fate is,” says Ozersky. Under his direction, researchers will measure mussel biomass and shell production and quantity in a set of lakes along a gradient of parameters such as size, invasion history and productivity. Measurements of shell quantity, composition and fate will be combined with information about sampled lakes to produce predictive relationships between lake characteristics and the role of shell material in geochemistry of ecologically important elements such as C, Ca, N and P. The proposed work will potentially contribute to more informed management of dreissenid-invaded waters in Minnesota and elsewhere.

Hydrogeochemical modeling of groundwater controls on sulfate and wild rice in streams 

Balancing mining interests and environmental health is a tricky business. This is especially the case now in northern Minnesota, where stringent standards regulating sulfate levels in surface waters aim to protect native wild rice but place strong pressures on mining operations with high sulfate discharge. In a recent reassessment of the standard, the Minnesota Pollution Control Agency presented data supporting wild rice vulnerability when elevated levels of sulfate are converted to sulfide in the porewater of lakes and streams. However, the MPCA study lacked an explanation of site-specific hydrogeochemical mechanisms. Timely clarification of sulfate effect in streams is vital to inform regulations that will affect Minnesota’s economy and wild rice habitat. PI Gene-Hua Crystal Ng and co-PI Amy Myrbo seek to clarify the effect of sulfate in streams by evaluating a new conceptual model in which groundwater as well as surface water influences porewater sulfide concentrations. Porewater is defined by the USGS as water occupying the spaces between sediment grains. 

“We propose to investigate a new conceptual model in which groundwater also influences porewater sulfide concentrations. We may discover that at some sites, sulfate can be transferred more efficiently to porewater through groundwater transport than through diffusion from surface water, and groundwater may serve to transport available Fe for sulfide immobilization,” said Ng.