Farm Families Alive and Well, September 2007, Vol. 13, no.4

News from Iowa’s Center for Agricultural Safety and Health (I-CASH)

Farm Families Alive and Well, Vol. 10, issue 4, 2004

News from Iowa’s Center for Agricultural Safety and Health (I-CASH)

Farm Families Alive and Well, September 2006, Vol. 12, no.4

News from Iowa’s Center for Agricultural Safety and Health (I-CASH)

Farm Families Alive and Well, September 2009, Vol. 15, no.4

News from Iowa’s Center for Agricultural Safety and Health (I-CASH)

Farm Families Alive and Well, September 2011, Vol. 17, no.4

News from Iowa’s Center for Agricultural Safety and Health (I-CASH)

Farm Families Alive and Well, September 2013, Vol. 19, no. 4

News from Iowa’s Center for Agricultural Safety and Health (I-CASH)

Farm Families Alive and Well, Vol. 9, issue 4, 2003

News from Iowa’s Center for Agricultural Safety and Health (I-CASH)

Dewaterability of sewage sludge by ultrasonic, thermal and chemical treatments

Sludges resulting from wastewater treatment processes have a characteristically high water content, which complicates handling operations such as pumping, transport and disposal. To enhance the dewatering of secondary sludge, the effect of ultrasound waves, thermal treatment and chemical conditioning with NaOH have been studied. Two features of treated sludges were examined: their rheological behavior and their dewaterability. The rheological tests consisted of recording shear stress when the shear rate increases and decreases continuously and linearly with time, and when it increases and decreases in steps. Steady-state viscosity and thixotropy were obtained from the rheological tests, and both decreased significantly in all cases with increased treatment intensity. Centrifugation of ultrasonicated and thermally treated sludges allowed the total solid content to be increased by approximately 16.2% and 17.6%, respectively. These dewatered sludges had a lower viscosity and thixotropy than the untreated sludge. In contrast, alkali conditioning barely allowed the sludge to be dewatered by centrifugation, despite decreasing its viscosity and thixotropy.

Iowa fish and wildlife news, Special Winter Issue [1999]

This DNR periodical contains current information on Iowa Fish and Wildlife Management.

Iowa fish and wildlife news, Special 1999 Fishing Issue

This DNR periodical contains current information on Iowa Fish and Wildlife Management.

Iowa fish and wildlife news, Special 1999 hunting issue

This DNR periodical contains current information on Iowa Fish and Wildlife Management.

Iowa Fish and Wildlife news, Special Fall Hunting Issue, 1998

This DNR periodical contains current information on Iowa Fish and Wildlife Management.

Farm Families Alive and Well, April 2014, Vol. 20, no.2

News from Iowa’s Center for Agricultural Safety and Health (I-CASH)

Performance of a chromatographic procedure used in the certification of reference material for polycyclic aromatic hydrocarbons in sewage sludge

Semi-automatic capillary gas chromatographic method with classical flame ionization detection, which satisfies the conditions for required performance and gave acceptable results within the framework of an interlaboratory certification programme for PAHs in sewage sludge, is described. The interesting feature of the procedure is that it incorporates automatic operations such as sample fractionation by semi-preparative HPLC, fraction collection at signal level recognition and evaporation under nitrogen flow. Multiple injections in the GC capillary column are performed in the on-column mode via an autosampler with temperature-programmable injector. Automatic data acquisition and chromatogram treatment are made via computer software. This partially automatic procedure releases personnel from tedious and time-consuming tasks and its robust character was validated through the certification of reference material for PAHs in sewage sludge, demonstrating its reliable performance.