Browsing by Subject "Land treatment of wastewater"
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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 Evaluation of an aerated soil reactor for the degradation of a hazardous organic waste(Texas Tech University, 1989-05) Brashear, Robert W.Not availableItem Evaluation of septic system drain fields(Texas Tech University, 2000-05) Ingram, Wesley WarrenAt the time of this thesis, the practice in Texas was to install absorptive drain fields in a septic system. The Texas On-Site Wastewater Treatment Research Council raised the question as to whether the combination of evapotranspiration and absorption in a septic system drain field in the arid and semi-arid regions of Texas could reduce the size of the drain field. As a result, a two-year study was undertaken in an attempt to answer that question. A field test facility was designed and installed at Reese Center near Lubbock, Texas. This facility consisted of septic tanks, header tanks, distribution system, and 18 drain fields. The 18 drain fields were divided evenly between wastewater and clean water. Three treatments were tested and include absorption (AB) fields, evapotranspiration (ET) fields, and combined evapotranspiration and absorption (ETA) fields. Each treatment and its control were installed in triplicate to enable statistical analyses of the results.Item Methodology for the sizing of storage requirements of slow rate land treatment systems using various management options(Texas Tech University, 1989-12) Abtew, WossenuSlow-rate land application is a means of treating and making beneficial use of wastewater. The cost of treatment of wastewater with the slow-rate system is dependent on the sizing of the storage requirements and the management of the system. Management decisions such as crop selection, choice of cultural practices, leaching scheduling, and water-nutrient application have a direct bearing on sizing of the effluent storage pond. In this study a numerical simulation method is used to develop a logical storage sizing methodology. A statistical method is presented to attach risk of failure and uncertainty involved in the decision making with the sizing of the storage. Stochastic mass balance models are developed to keep track of flow of water, nutrients, and dissolved solids in the sub-systems of the slow-rate system. A stochastic optimization model for maximizing application rate of water and nutrients at all times is formulated and this in return minimizes the need for storage. The role of management decisions on the size of the system and treatment efficiency is evaluated. Nutrient level regulation through aging of wastewater is presented as a means of minimizing pollution.