June 2013, Vol. 25, No.6

Research Notes

Lagoons remove majority of microconstituents from wastewater  

Aerated lagoons reduce concentrations of most but not all microconstituents. Researchers examined how effective rural lagoon systems were at removing 21 commonly used microconstituents from wastewater, according to a University of Illinois (Urbana) news release. Wei Zheng, senior research scientist at the Illinois Sustainable Technology Center (Champaign) and adjunct faculty member in the University of Illinois Department of Natural Resources and Environmental Sciences, led the study, which was conducted jointly with the Illinois State Water Survey (Champaign), the news release says. 

Researchers collected water samples in September and November from a rural Illinois water resource recovery facility that uses two aerated lagoons for biological treatment and a sand tank for filtration. Samples from various steps throughout the treatment process were collected for analysis. 

After testing for 21 microconstituents and hormones, the research team found that the system reduced concentrations of most of the tested compounds except carbamazepine, a drug used to treat epilepsy and bipolar disorder that is difficult to remove from wastewater. Overall removal efficiency ranged from 88% to 100% in September for most compounds, and there were no detectable steroid hormones in the effluent, the news release says.  

Samples collected in November contained higher concentrations of all detected microconstituents than those collected in September. Zheng explains that this likely is because microorganisms that break down contaminants work best in warm weather, the news release says. 

While the researchers found a relatively high removal of microconstituents by the lagoon, they also found that the waterways in surrounding watersheds had a significant increase in the occurrence of microconstituents. The results point to the need for more research to understand the environmental fate and effects of microconstituent and hormone contaminants in waterways, the news release says.  

The paper “Occurrence and removal of pharmaceutical and hormone contaminants in rural wastewater treatment lagoons” was published in the journal Science of the Total Environment. 

  

Water industry increases demand for detailed real-time water data  

Global Hydrological Monitoring Industry Trends , a report published by Aquatic Informatics Inc. (Vancouver, British Columbia) provides data on the state of the water industry.  

More than 700 water resource professionals from 90 countries participated in a global study conducted in fall 2012. The study identifies the trends in water monitoring technologies, strategies, and best practices, according to Stuart Hamilton, Aquatic Informatics’ senior hydrologist. 

The report reveals an increasing demand for metadata and higher-level analysis, decline in tolerance for data faults, and the expectation that quality-controlled data be published sooner. By 2022, respondents forecast they will be publishing daily averages and unit values through dynamic content using Web 2.0 tools, Web services, and mobile devices, the article says.  

“Today, water resource managers are collecting, storing, managing, analyzing, and publishing more continuous hydrological data than ever before,” the article says. There is an increased demand for hydrological monitoring networks to serve both multiple needs and multiple purposes. And 72% of water professionals reported that they would need more monitoring stations to adequately meet all of their program goals, the article says.  

The report identifies a decline in the use of analog paper charts and major growth in the use of digital multichannel data loggers, with a trend of adopting automated sample collection and multiparameter water quality sensors, the article says. In addition, the most popular communications technology is digital data retrieval. Another trend is the adoption of Web-enabled sensors, which were being used for 4% of stations in 2002, now are used for 20% of stations, and are forecast to be used for about 40% of stations by 2022, the article says. 

“Water resource managers have turned to real-time communications technologies for data transmission,” the article says. “They also are implementing redundant hardware as a best practice to guarantee timely availability of critical water data.” Increased use of advanced technology has resulted in large volumes of complex data. The report finds it also is important that the data be communicated clearly and through a widely accepted standard operating procedure. “Water resource professionals are concerned with ensuring data quality, defensibility, and interoperability,” the article says. “Water managers want to produce data that can be trusted.” 

“Respondents using actively licensed commercial software reported better being able to meet evolving stakeholder expectations for real-time data products and services, metadata availability, higher level analysis, and timely reporting and publishing,” the article says. New technologies and data management solutions are being deployed so real-time, high-quality information is more readily available, the article says.  

For more information, see the report at http://pages.aquaticinformatics.com/Water_Report.html.  

  

Setting a path to increasing nutrient use efficiency  

  

Our Nutrient World , a report commissioned by the United Nations Environment Program (Nairobi, Kenya), describes how humans have altered the natural flows of nitrogen, phosphorus, and other nutrients.  

The report, which describes a study carried out by experts from 14 countries, recommends a 20% improvement in nutrient use efficiency by 2020, reducing the annual use of nitrogen fertilizer by 20 million Mg. The goal of “20:20 for 2020” would provide a net savings of about $144 billion/yr (£110 billion/yr), according to a Centre for Ecology and Hydrology (Wallingford, England) news release.  

Pollution sources include emissions from agriculture and combustion of fossil fuels. While some countries have substantially reduced emissions from combustion sources and wastewater treatment, much less progress has been made in reducing emissions from agriculture or regarding citizens’ personal choices, the news release says.  

In addition, about 80% of harvested nitrogen and phosphorus is consumed by livestock, rather than directly by humans. This shows that “global nutrient supply and pollution are dominated by humans’ choice to consume animal products,” the news release says. 

The report describes this as a global problem and calls for an intergovernmental framework to address such issues. It also proposes a road map for this type of agreement. According to the news release, proposed actions include 

improving the management of nutrients in agriculture by such activities as using precision agricultural methods, including “planting” fertilizer pellets into the ground; reducing nutrient losses from industry    and wastewater treatment — for

example, by recycling available resources and developing methods to recapture nitrogen oxides from combustion sources;
 improving local optimization of nutrient flows, connecting arable and livestock farming to improve nutrient recycling

opportunities;
 lowering consumption of animal protein; and localizing agricultural production to help improve nutrient recycling and reduce nutrient loss. The researchers note that efficiency will require a package of measures that include

research, education, demonstration, new technologies, and improved management techniques, the news release says.
  

Finding an alternative to determining anaerobic digester stability in April WER   

Determining anaerobic digester stability can be a useful tool, especially when increasing organic loading to produce more methane. Seattle University researchers set out to examine if a water displacement system could be used in place of gas chromatography analysis to measure digester stability. Results of this research are published in the April issue of Water Environment Research. 

Acetate uptake bioassay can be used to monitor digester stability, typically by measuring methane gas production from serum bottles over time with a gas chromatograph. But the expense and limited availability of the gas chromatography equipment makes the process uncommon. 

The researchers compared and evaluated the water displacement system as an alternative for gas chromatography and determined that methane generation rates measured by both methods were statistically the same, the paper says. The method’s precision, calculated by measuring near stoichiometric volumes of carbon dioxide gas production from abiotic tests using sodium carbonate and hydrochloric acid, varied less than 5%.  

This finding could make the adoption of acetate uptake bioassay using a water displacement system for predicting digester stability “a practical option for treatment facilities,” the paper says.  The report, “Avoiding Digester Upset,” is available as an open-access document and can be downloaded free at http://goo.gl/5N3KV.   

Water Environment Research allows open access to one article per issue on a range of important technical topics such as nutrient removal, stormwater, and biosolids recycling.