Browsing by Subject "Sewage sludge"
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Item Cattle grazing and biosolids in West Texas(Texas Tech University, 2004-05) Avila, Jose-MiguelLime stabilized biosolids applications on rangelands were evaluated by cattle grazing in 2000 and 2001 on six, 16-ha pastures. Three pastures were treated with 20 dry ton per ha and 3 untreated pastures were used as a control. Average daily gain of steers grazed on test pastures for 120 days were evaluated through two grazing seasons. Forage samples were collected to determine forage availability and forage quality. At the end of each performance trial, animal tissues were collected from liver, muscle, kidney, and heart to evaluate trace elements. An additional four, 8-ha pastures were used to document animal behavior. Each of these four pastures was divided in half. Biosolids was applied in one half of the pasture at 20 dry ton/ha; the other half was untreated. Animal behavior was evaluated in 4-day consecutive periods, during 12 hours of direct observations at the beginning and end of each grazing season of the performance trial. Average daily gain was similar (P>0.05) between treated and untreated areas with 0.249 and 0.238 kg per animal and with 0.140 and 0.139 kg per ha in year 2000, as well as 0.435 and 0.377 kg per animal and 0.154 and 0.118 kg per ha in year 2001. Tissue samples from steers grazing on treated pastures were similar in trace elements (P>0.05) compared with those collected on untreated pastures. The steers spent 5 hours and 40 minutes per day grazing in 2000 with 57% of grazing time spent in the biosolids-treated area. In 2001, steers spent 6 hours and 53 minutes grazing with 56% of grazing time spent in the biosolids area. In conclusion, biosolids affect animal performance when conditions are favorable especially rainfall and temperature. However, steer grazing behavior showed preferences for grazing activities on the biosolids areas. Biosolids applications positively affect forage quality, especially crude protein.Item Effects of biosolids on desert grasslands(Texas Tech University, 1995-08) Benton, Mark W.Anaerobically digested biosolids were applied to experimental units containing a monoculture of either tobosagrass (Hilaria mutical or alkali sacaton (Sporobolus airoides). Biosolids were applied at varying rates (0, 7, 18, 34, or 90 Mg/ha) during either the winter or summer for 1 year only or for 2 consecutive years. In addition, one-half of the plots were provided supplemental irrigation throughout the growing season. Effects of biosolids on standing crop yield of both species and chemical composition of tobosagrass were evaluated. Both species responded better to winter season application at the end of the first growing season. Standing crop of tobosagrass and alkali sacaton were increased above winter controls for all biosolids rates following winter season treatment. Tobosagrass standing crop was increased from 54 to 147% and alkali sacaton increased from 42 to 100% with winter biosolids amendment. Alkali sacaton showed essentially no response to summer biosolids application at the end of the first growing season. Tobosagrass standing crop was increased above summer controls for the three highest rates following summer treatment. At the end of the second growing season there were no differences between tobosagrass or alkali sacaton plots receiving 1 year only or 2 consecutive years of apphcation with 0, 7, 18, and 34 Mg/ha of biosolids. Standing crop significantly diminished, however, in plots receiving 2 consecutive years of treatment with 90 Mg/ha of biosolids as compared to plots receiving 1 year only treatment at this rate. There were no differences in winter and summer season application in plots that received biosolids for two consecutive years. Standing crop was generally greatest for plots receiving biosolids at either 18 or 34 Mg/ha. Lastly, forage quality of tobosagrass was improved as evidenced by increased total Kjeldahl nitrogen (TKN) at the end of the first growing season. In addition, there was no evidence of trace metal accumulation in these plants.Item Exploiting synergy in animal co-product bisolids processing: the cactus project(2006-05) Pasupuleti, Divya; Morse, Audra; Shelly, Dennis C.The current project is a feasibility study prepared for the Dumas Economic Development Corporation in Cactus, Texas for the purpose of evaluating the feasibility of constructing a facility that processes leather wastes to produce useful products. The project aims at developing a zero discharge strategy by fully utilizing the wastes from the leather making industry and converting them into value-added products. The model of the comprehensive animal co-product biosolids processing facility consists of six processing units namely the tannery, the keratin unit, the collagen unit, the biodiesel unit, the modular agriculture unit, and the biogasification unit. All the above units are linked to each other in such a way that the waste produced by one unit is used as input to another unit, leading to zero waste discharge. Simulation models of all the units were developed using the SuperPro Designer software. The tannery processes raw goatskins and converts them into wet blue leather. In the process, the tannery generates wastes like hair pulp, fleshing grease, wastewater, and waste biosolids. The hair sludge and fleshing grease produced from the sanitization of hides in the tannery are sent to the keratin unit and biodiesel unit to obtain useful products like keratin and bio-diesel, respectively. The collagen unit is used to produce gelatin, protein, and basic chrome sulfate from wet blue shavings. The chrome sludge produced in this process is sent to the tannery to enable sanitization of the hides. The wastewater produced from all the above processes is sent to a modular agriculture unit, to grow duckweed and baitfish. Virtually all the waste biosolids are sent to a biogasification unit to produce power, steam, and ash. The annual operating costs for all the units in the facility were determined based on current prices of equipment, raw materials, labor, and utilities. The revenues obtained from the product sales of each unit determined the profitability. The profítability of the entire facility was determined based on the economics of the individual units. The total capital investment on the facility was approximated at $8,890,000. The total annual operating costs were estimated to be $7,466,000. The total annual revenues were found to be $9,581,000. The total gross profit obtained from the entire facility was estimated to be $2,115,000. The total net profit was found to be $1,763,000. The payback time is just 5 years. The results of the study indicate that the Cactus facility provides economic benefits and reduces environmental impact by eliminating the discharge of wastes.Item Influence of construction water quality on the performance of road base and subbase materials(Texas Tech University, 2004-08) Bhongir, Chandra PrakashIn some parts of Texas, during periods of draught and increased construction works, water has become a precious commodity, especially for areas in the state which receive very little rainfall. This puts the construction projects on-hold, which requires large quantities of water. One way to reduce the demand for drinking water is to substitute non-drinking quality water in construction applications. However, there may be some adverse impacts of using alternative water in construction applications. The research included the study of most critical concerns that would arise when water from alternative water sources is used in the construction of road bases and subbases. These concerns are: (a) the potential impact that soluble minerals in alternative water may have on soil parameters that are used in material selection (i.e., Atterberg Limits and Bar Linear Shrinkage) and (b) the effect that sulfate ions in water may have on the potential for sulfate heave in base layers stabilized with calcium-based stabilizers. A comprehensive test program was undertaken selecting five different soils, which would cover the broad range of soil types found within the geographic parts of Texas. The types of alternative water used were Treated Effluent from Wastewater Treatment Plants, Ocean Water, and Brine Water, each having different concentrations of salinity and sulfates. The soil samples were tested with and without adding alternative water to evaluate the impact of alternative water on the soil samples. A predictive model was developed that would allow preliminary evaluation of candidate alternative water sources to determine their suitability.Item Land application of combined sludge and secondary effluent(Texas Tech University, 1995-05) Brooks, Wade AllenThe effect of sewage sludge on soil, plant tissue, infiltration of the soil, and total biomass producation was studied. The crops grown for the project were alfalfa, wheat, and sorghum. For alfalfa the application rates were 0, 17.9, and 35.9 mt/ha (0, 8, and 16 ton/acre). There were two plots of wheat and sorghum, one had raw sludge applied and the other had lime-stabilized sludge applied. The application rates for the raw sludge plots were 0, 9.0, 17.9, 26.9, and 35.9 mtOia (0, 4, 8, 12, and 16 ton/acre). The application rates for the lime-stabilized plots were 0, 9.0, 17.9, and 26.9 mt/ha (0, 4, 8, and 12 ton/acre). The was an accumulation of metals in the soil but with the pH^S.O the metals should be relatively immobile. The plant tissue showed an increase in micronutrients for the project. Infiltration and total biomass production did not increase significantly with an increase in application rate. In the next year or two years the total biomass production should begin to increase, because the organic nitrogen should be converted to ammonium nitrogen by soil bacteria.