Glass Fiber Filter

An especially pungent use for glass fiber filters is described in the latest issue of the Soil Science Society of America Journal. In the paper, “Influence of Dissolved Carbon and Nitrogen on Mineralization of Dilute Liquid Dairy Manure” two scientists from the University of California examined the wastewater used to flush dairy cow waste for the presence of these elements.

On dairy farms in which the milk cows are confined, water is used to flush away the manure and is then stored in lagoons to be treated for coarse solids before being re-applied to crop fields through irrigation. Refuse reuse if you will. One problem with this procedure is that if there is too much dissolved Carbon or Nitrogen in the wastewater it can create groundwater contamination.

For this study, the researchers collected wastewater samples from seven lagoons and analyzed them in order to investigate the relationship between the starting levels of Nitrogen and Carbon and the wastewater’s mineralization behavior. Their methodology included determinations of Totals Solids (TS) and Total Suspended Solids (TSS) by filtering the manure through a series of glass fiber filters, including the Advantec GF75 (0.3 micron) at several points. The GF75 was also used to filter wastewater samples prior to gravimetric analysis.

In this case, the authors found that the amount of Nitrogen that will be mineralized for crop consumption is very likely due to how much dissolved Carbon and Nitrogen is present on denitrification. Further investigation will be needed before scientists can accurately predict how much Nitrogen the crops treated with this water are actually exposed to.

The full paper is available here for American Society of Agronomy subscribers.

The Toxicity Characteristic Leaching Procedure as described in EPA Method 1311 is designed to determine the mobility of organic and inorganic analytes present in different forms of waste. This procedure involves extracting and filtering waste samples using specific types of glass fiber filters and extraction vessels. When following this procedure, there are two kinds of vessel that can be used to extract samples for analysis, the bottle extraction vessel and the zero-headspace extraction vessel. Which type of vessel you use depends on the volatility of the analyte being sampled. Nonvolatile analytes can be tested using a bottle extraction vessel, while the zero-headspace extraction vessel must be used when testing for the mobility of volatile analytes. Examples of volatile analytes include: acetone, benzene, methanol, toluene, and vinyl chloride.

The EPA Method specifies that the filter for both liquid and solid waste (the latter is filtered after solid phase extraction) be a 0.6 to 0.8 micron glass fiber filter. The TCLP grade filters, which are designed precisely to meet the requirements of EPA Method 1311, feature a 0.7 micron pore size and have been acid treated and rinsed with deionized water at multiple stages to handle volatile analytes. When using these filters in conjunction with a zero-headspace extraction vessel, the EPA Method dictates that the TCLP filter should have a diameter between 90 mm and 110 mm (TCLP-2 and TCLP-3 meet this specification).

For more information on the Toxicity Characteristic Leaching Procedure, consult the complete text of EPA Method 1311 here.

This morning we officially launched a new website specifically for Glass Fiber Filters and accessories at www.glassfiberstore.com! Here you will find full lines of glass fiber products from Sterlitech, Advantec MFS, and Munktell, as well as brand comparison tables, FAQs, and product specs to help your decision-making process.

We will still continue to offer glass fiber filters on the main Sterlitech site, but since there are so many different items that fall into the glass fiber category we wanted to create a specific area to showcase them that would be easier to navigate for people looking exclusively for these items. Building the new site has also allowed us to include specialty products that you won’t find on the Sterlitech website, like grades of filter paper for breweries, wineries, seed testing, soil analysis, and sugar laboratories.

Because Glass Fiber Store is part of the Sterlitech network you can use your existing Sterlitech account credentials to place orders on both sites. We’re also bringing the same flexible options and dedicated customer support to Glass Fiber Store that has made Sterlitech successful. Take a look around for yourself and then let us know what you think in the comments!

Read our press release on Glass Fiber Store here.

In searching for new weapons in their fight against the destructive mountain pine beetle, scientists at the USDA Forest Service are experimenting using filtration techniques to create more effective insecticide treatment. It is estimated that 8% of forests in the United States are at risk to insect or disease outbreaks; among this percentage the mountain pine beetle is considered the biggest threat.

It’s necessary to find new solutions to protect these trees because of concerns about the future availability of one of the most commonly used insecticide chemicals, carbaryl, for environmental reasons. A study published this year examined the effectiveness of different concentrations of carbaryl along with two other known insecticides, cyantraniliprole and Cyazypyr (30 Scrabble points!).

For this experiment the researchers performed two different assays, one involved exposing the beetles to insecticide with filter paper and one through a topical treatment. For both tests they used 1 mL of various concentrations of the insecticides along with 934-AH filter paper (1.5 micron pore size, 90 mm diameter) stored in a sterile petri dish and dried in a fume hood.

In the filter paper assay, small holes were drilled into the petri dish to provide ventilation and captured beetles were placed on the filter paper. The health of the beetles was then assessed at regular intervals to determine the effectiveness of each insecticide concentration. In the topical assessment, the insecticide was applied directly onto the beetles which were then placed on top of the filter discs.

The results of the filter paper assays, which the authors believes more closely approximates field conditions than topical assays, found that is possible that much smaller amounts of carbaryl could be effective in the field, which is good news for the environment as concerns over the toxicity of this chemical have grown. As such, the authors recommend that smaller concentrations of carbaryl be tried in the field. Take that, pesky beetles!

Read the full report here

Quartz Fiber Filters for High Temp. Needs

This week we added another new item to our catalog - Quartz Fiber Filters. These filters are especially useful for high temperature filtration applications since they can withstand temperatures over 500°C.

Other nice things about these filters include their indefinite storage life and their high chemical resistance. Right now we have grades QR100 and QR200 available in diameters ranging from 21mm to 150mm.