Soil and grass filtration of a domestic sewage effluent for trace element removal was investigated by applying oxidation-pond-treated waste water to twelve 2.44-meter-long, 30.5-cm-diameter, lysimeter columns and to a half-acre plot planted to common bermudagrass. Bermudagrass was also planted on the soil columns to aid in the removal of accumulated metals, thus prolonging the filtering capacity of the soil system. Four irrigation patterns, continuous flooding, alternate day flooding, one day wet-three days dry cycles and two days wet-five days dry cycles, were employed during the eleven week lysimeter test. Water samples were extracted from the soil columns at eight sampling depths to determine the soil depth at which the various trace metals were removed from the filtrate by the processes of adsorption, absorption and biological assimilation. Atomic absorption spectrophotometric techniques were used to determine the concentrations of iron, manganese, hexavalent chromium, nickel, copper, zinc, lead, cadmium, cobalt and strontium in the applied effluent, filtrate, soil and grass clippings. Filtrate samples for trace metal analysis were also extracted at shallow depths and from two groundwater zones at 9.1 and 15.2 meters depth under the grass plot. In the lysimeter study, iron, manganese, nickel, copper, zinc, lead and cadmium were removed from the filtrate at, or near, the soil surface. Some copper, zinc and cobalt were found in the deeper filtrate samples during periods of high infiltration rates and in the presence of anaerobic conditions. Smaller amounts of manganese, nickel and lead were also found at the deeper sampling points. Strontium was not removed from the water percolating through the calcareous soil employed in this study. Chromium and cobalt were not present in measurable quantities in the applied effluent. Iron and manganese were removed from the soil system in the grass clippings in the greatest amounts. Traces of copper, zinc and cadmium were also detected in the grass clippings. Larger quantities of iron, manganese and copper were detected in the filtrate at the grass plot than at comparable depths of the lysimeter columns, probably due to effluent applications at the grass plot over a period of two years. Lower quantities of nickel and lead in the filtrate at the grass plot were attributed to leaching by effluent during grass filtration tests, prior to the trace metal experiments. The concentrations of trace metals in the filtrate at the bottom of the lysimeter columns and in the groundwater zones at the grass plot were irsignificant by United States Public Health Service drinking water standards (1962) and would meet most other water supply requirements. The total nitrogen and nitrate contents were successfully reduced when a combination of aerobic and anaerobic environments were present in the soil system. Total nitrogen and nitrate levels were not reduced by grass filtration through 304.8 meters of dense grass. Fewer total coliform organisms were detected in the aerobic lysimeter columns than in the continuously flooded columns. The majority of coliform organisms detected in the filtrate at the 61 cm depth were believed to be of non-fecal origin. The chemical oxygen demand of the applied effluent was reduced to as low as 105 mg/L by grass filtration. A substantial portion of the remaining COD was attributed to high algal concentrations. The most effective treatment employed in this study was the one day wet-three days dry irrigation cycles. This treatment provided the necessary aerobic environment for trace metal removal from the effluent, nitrification of reduced nitrogen compounds and coliform organism elimination. The flooding period provided the anaerobic conditions required for denitrification losses of nitrate.

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 137-138). / xi, 138 leaves, bound ill. (some col.) 29 cm

The adsorption of low concentrations of heavy metals, such as zinc, copper, lead and mercury, by various British Columbia coals was investigated. Five British Columbia coals were used as adsorbents for the four heavy metals described above. Batch tests were run on all five coals, namely, Hat Creek Oxidised, Hat Creek Unoxidised, Cominco Oxidised, Cominco Ash Waste and Cominco Production Coal. The optimum contact time for batch tests was found to be 60 mins. Batch tests provided a quick comparison of the adsorptive capacities of the five coals. Based on the batch tests data, the best performing coal from each of the Hat Creek and Cominco groups, namely, Hat Creek Oxidised and Cominco Ash Waste were chosen for further investigatory work using column tests. For the column tests, the influent concentrations were 2 mg/ℓ and less for zinc, copper and lead. Column work with mercury was carried out with influent concentrations of 5 μg/ℓ and less. Column tests showed the following:- a) Varying the cross-sectional area of the coal column from .001 ft² to .002 ft² has no significant influence on the adsorptive capacity. Both columns have diameters more than 10 times that of the average coal particle. b) The most crucial factor affecting adsorptive capacity is the pH of the influent. There is a definite decrease in capacity with decreasing pH. c) The capacity decreases with increasing flow rate, but the relationship is not linear. The decrease in capacity due to a flow rate increase from 1 to 3 Igpm/ft² is much greater than the decrease in capacity due to an increase from 3 to 5 Igpm/ft². d) Comparing the adsorptive affinities of zinc, copper and lead, it is seen that lead displayed the greatest affinity with copper second and zinc third. At 10% breakthrough concentration, the capacities displayed by Cominco Ash Waste coal for lead, copper and zinc were in the ratio of 12:6:1. The influent pH and initial concentrations involved were 4.0 and 2 mg/ℓ respectively, and the flow rate was 1 Igpm/ft². e) Using influents containing a mixture of zinc, copper and lead results in smaller individual capacities for Zn, Cu and Pb than would be achieved with single solute influents. But the total overall capacity of the coal for heavy metals is greater with mixed influents than with any single solute influent. f) Tests with mercury influents show that deterioration of the concentration of the mercury solution occurs at concentration of 5 μg/ℓ and less. g) Of the two coals chosen for column test work, Hat Creek Oxidised is the superior coal with regard to the adsorptive capacity of heavy metals. Tests run at an influent pH of 4.0 and influent concentrations of 2 mg/£ of each metal, showed the ratio of capacities of Hat Creek Oxidised: Darco activated carbon: Cominco Ash Waste for Zn to be 12.1 : 1.2 : 1.0, for Cu to be 11.9 : 1.7 : 1.0 and for Pb to be 3.8 : 0.7 : 1.0. An attempt was made to correlate the column effluent pH with the effluent metal concentration. It was found that this correlation is more pronounced at lower influent pH values. During the course of the column work, a growth of fungus was observed at the top of the coal columns. It is possible that adsorptive capacities were affected by this fungus. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

No description available.

Not available / text

Grit is usually removed from sewage flow just prior to treatment by some type of grit chamber, often little more than a wide channel with a depressed trough to trap the grit. Three shapes of grit chamber troughs were studied in a model to determine which was the most efficient for the selective capture of grit. The model was constructed of wood, with plastic, interchangeable troughs, and was six inches wide by about ten feet long, including a three foot approach channel to the chamber. The three troughs were six inches deep with 2:1, side slopes and differed, therefore, only in bottom length. Trough 1 tapered to a point, Trough 2 had a four inch bottom length, and Trough 3 had an eight inch bottom length. Water from a town main was run through the apparatus at velocities varying from 0.11. to 0.8 fps and depths from 0.1 to 0.33 feet. Grit was added, as the flow entered the approach channel, through a funnel. Ordinary construction sand was used as grit after being sieved to obtain 0.1 and 0.2 mm diameter particles. When all the grit had been added the flow was stopped and all grit which had not passed the trough was removed and measured. This measurement when compared with the known amount of grit which was added produced a value of per cant grit passing the trough for each run. Trough 2, the medium length trough, was found to be relatively most efficient for the selective capture of grit. / Master of Science

Call number: LD2668 .T4 1986 B46 / Master of Landscape Architecture / Landscape Architecture/Regional and Community Planning

published_or_final_version / Architecture / Master / Master of Landscape Architecture

No description available.

Submitted in part fulfillment of the requirements for the Degree of Masters in Technology in Chemical Engineering, ML Sultan Technikon, 2003. / Whilst microfiltration (MF) has numerous uses and advantages over conventional separation processes it does have certain limitations. MF membrane process can effectively remove turbidity but cannot sufficiently remove low molecular organics. For a sufficient removal of such particles adaptations and modifications to the membrane has to be made or additional removal processes (e.g. nanofiltration or reverse osmosis) has to be added. This project makes an attempt at addressing the former issue. In MF, a membrane on a support performs the filtration. There are various types of materials used as supports e.g. ceramics, porous steel tubes, polymers etc. These materials are usually rigid or semi-rigid and thus offer the advantage of maintaining their shape thus enabling operation at high pressures. This project will concentrate exclusively on woven fibre microfiltration (WFMF). This is a tubular cloth-like filter, which becomes rigid when feed flows into it. / M