The Labor Required for Crop Production in Ohio

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Effects of Coagulation and Fenton\u27s Oxidation on the Removal of UV-Quenching Substances in Landfill Leachate

Landfills are the primary method to dispose of municipal solid waste, and the water leaching from landfills contains products of physiochemical and biochemical reactions, presenting an important environmental challenge. In many cases, leachate is diverted to publicly owned treatment works (POTWs) for treatment. However, even if leachate contributes less than 1% of the total wastewater flow, recalcitrant dissolved organic matter (DOM) containing ultraviolet-quenching substances (UVQs) remains in the leachate after biological treatment, contributing to a low UV transmittance, thus also decreasing the effectiveness of UV disinfection. To analyze the removal of UVQS of landfill leachate before sent to POTWs, this study researches and compares coagulation/flocculation and Fenton’s oxidation, an advanced oxidation process, to remove UVQS in landfill leachate by analyzing the differences in soluble chemical oxygen demand (sCOD), dissolved organic carbon (DOC), UV absorbance at 254 nm (UVA254), specific UV absorbance at 254 nm (SUVA254) and tryptophan, fulvic acid, tyrosine, and marine humic acid-like fluorescent intensities with an excitation emission matrix (EEM) and functional groups with Fourier-transform infrared spectroscopy (FTIR) to better understand the removal mechanisms. This study also evaluates a Fenton’s dimensionless oxidant dose (DOD) of 0.7 for three different leachates to analyze trends in treatment levels. DOD is a normalization of the reactive oxygen present to the initial sCOD. During coagulation studies, three initial pH values (5.5, 6.5, and 8.2) and FeCl3 dosages (1 g/L, 5 g/L, 10 g/L) were studied. Initial pH of 6.5 and 10 g/L FeCl3 dosage reached the maximum DOC removal, and UVA254 and SUVA254 reduction, reaching 65.1%, 2.6 cm-1 (from 22.4 cm-1), and 0.62 L/mg-M (from 1.86 L/mg-M), respectively. This treatment also had large DOM removals with an affinity toward fulvic acids, however it was not effective in removing carboxylic acid functional groups. For Fenton’s oxidation, first, two leachate samples taken from a landfill in Greenville County, SC, at different times, treated with a 24-hour reaction time at a DOD from 0.07-0.72 with a molar ratio of 5:2 for H2O2:FeCl2 at pH 4, were studied. The 0.72 DOD dose led to the highest decrease in UVA254 to 4.2 cm-1 and SUVA254 to 0.63 L/mg-M, with a DOC removal of 48.8%. All treatments targeted fulvic acids above other DOM. The higher the DOD, the more DOM removed, and the better able Fenton’s oxidation was at breaking down the C=C in aromatics and COO- in carboxylic acids. From analyzing the precipitate formed during Fenton’s treatment, it was also found that at lower DOD doses the treatment is partially due to coagulation only, whereas at higher concentrations the treatment oxidation accounted for all DOC removal. When comparing these results to a leachate taken from a landfill in Orange County, FL treated with a 0.7 DOD, the removal trends of DOC, UVA254, and SUVA254 were not consistent, suggesting normalizing treatment requirements for UVQS removal may be better with SUVA254 instead of sCOD This research successfully shows that coagulation/flocculation and Fenton’s oxidation can remove UVQS, but due to the complex nature of the UVQS, neither treatment removes all constituents. The results indicate coagulation/flocculation will result in better treatment, but it is likely Fenton’s oxidation will result in a larger number of biodegradable organics that can be removed during biological treatment at a POTW

Six degrees of freedom vibration isolation using electromagnetic suspension

Experimental data are presented for modeling an electromagnet. Control laws are considered with and without flux feedback and with position and orientation information of the suspended body. Base motion and sensor noise are the principal disturbances. Proper selection of the geometrical operating point minimizes the passive coupling above the bandwidth of the control and filtering can attenuate the high frequency content of sensor noise. Six electromagnets are arranged in a configuration which optimizes the load support and provides control over all six degrees of freedom of the suspended body. The design is based on experimental data generated with a specially designed test facility. Application for suspension of a gravity wave antenna is discussed

Response of Sweet Corn to Irrigation Management

As most growers know, high sugar sweet corn has shallow roots and does not germinate well in cold soils. A clear plastic mulch improves the stand, hastens maturity in cool springs, and improves marketability. To utilize 4 ft standard clear plastic the traditional seeding method must be changed. The seeding arrangement involves twin rows, 18 in. apart, with in-row spacing at 12 in. and with 2 plants per position. Center to center of the beds varies from 5.5 to 7 ft. Plant population is higher, approximately 29,000 plants per acre. Irrigation is usually required for high quality yield. Trickle irrigation tubing placed down the center of each bed or 9 in. from each row would allow timely water application based on crop demand. Our objective for the last several years has been to evaluate irrigation scheduling models for sweet corn planted in twin rows on clear plastic mulch

The Three-Component System

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Issues of alcohol misuse among older people : attitudes and experiences of social work practitioners

This small-scale qualitative research focused on the experiences of social workers vis--vis older people who misuse alcohol. Based in an Older People's Team in the west of Scotland, the study explored service provision for alcohol misuse and examined whether practitioners felt the existing services provided by the Substance Misuse Team were effective in meeting the needs of older people with an alcohol problem. Using semi-structured interviews, data were collected from 18 participants, the majority (14) of whom were female and whose ages ranged from 31 to 54 years. Several key themes emerged including the extent of alcohol problems among older people and the complex reasons that cause older people to misuse alcohol. These reasons commonly related to the increasing challenges of old age. The data also demonstrated that current services are not meeting the needs of older people. Practitioners identified a need for an 'age-specific' approach to target more effectively the complex needs of older people. Recommendations from practitioners included ways to develop new and more effective services, including a more age-specific service, such as providing longer term support in older people's own homes, using a specialised support worker, and increasing staff training on alcohol use among older people