• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 22
  • 5
  • 4
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 40
  • 40
  • 40
  • 14
  • 9
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 5
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Modeling the impact of logging debris on the dissolved oxygen balance of small mountain streams /

Berry, John David. January 1974 (has links)
Thesis (M.S.)--Oregon State University, 1975. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.
12

Relationships of dissolved oxygen and biochemical oxygen demand in sewage effluent releases

Sebenik, Paul Gregory, 1941- January 1975 (has links)
No description available.
13

Mediated biochemical oxygen demand biosensors for pulp mill wastewaters

Trosok, Steve Peter Matyas. January 2000 (has links)
Mediated microbial sensors utilizing two different yeast isolates (SPT1 and SPT2) were developed for the estimation of biochemical oxygen demand (BOD). Measurements of glucose/glutamic acid (GGA) standard solution with potassium ferricyanide mediation resulted in linear ranges extending from the detection limits (i.e. 2 and 5 ppm BOD) to 100 and 200 ppm BOD for the SPT1- and SPT2-based sensors, respectively. The standard error of the mean (SEW for 10 ppm. BOD measurements was 10.1% (SPT1) and 3.9% (SPT2). Response reproducibility had 10.6% error between three identically prepared SPT1 sensors. Response times for concentrations of 20 ppm BOD were within 10 minutes. For pulp mill effluent, the detection limits were 2 (SPT1) and 1 (SPT2) ppm BOD, with SEMs of 3.6% and 14.3% for the SPT1 and SPT2 sensors, respectively. Based on the results obtained in this study, it is concluded that SPT2 is the more suitable biocatalyst for pulp mill wastewater analysis. / While 18S rRNA gene sequence analyses, including BLAST homology searches, have suggested that isolate SPT1 is a close relative of Candida sojae (99.8% homology), no close matches have been found for isolate SPT2. The closest match for SPT2 was to Candida krusei (76.0% homology). Evidence from biochemical tests, fatty acid analysis, and 18S rRNA gene sequence analyses, indicates that isolate SPT2 is a novel yeast species.
14

An evaluation of the accuracy of biochemical oxygen demand and suspended solids analyses as performed by Wisconsin laboratories

Weber, Susan. January 1978 (has links)
Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaf 54).
15

Mediated biochemical oxygen demand biosensors for pulp mill wastewaters

Trosok, Steve Peter Matyas. January 2000 (has links)
No description available.
16

A laboratory study of reduction of the biochemical oxygen demand of synthetic sewage by Zoogloea ramigera

Thompson, Edwin E. January 1951 (has links)
In order to improve the design and to control satisfactorily the operation of the modern sewage disposal and industrial waste treatment plants, a great deal of work remains to be done by competent sanitary engineers, biologists, and chemists. It is the general belief that the stabilization of organic wastes is a biological phenomena. This indicates that a concentrated study of the organisms that are responsible for such stabilization should be undertaken and the part that each organism contributes should be evaluated The lack of specific knowledge has resulted in "rule of thumb" methods of design and control. A considerable amount of work on the biology of sewage disposal has been done by the New Jersey Experiment Station (4)(5)(8); by C.T. Butterfield and Elsie Wattie of the U.S. Public Health Services (10) (13) and by others, but a concentrated effort is still needed. James B. Lackey (1), has done an excellent job in summing up the work accomplished to date in the field of sanitary biology in his article “Sewage Treatment Biology”. In this article, Dr. Lackey lists four things that must be known before a clear picture can be presented on the subject of sewage and waste treatment. These points are as follows: (1) More precise information on the species of each group of organisms working in treatment plants. (2) The relative abundance of each so that no important (numerically or volumetrically) organism is neglected. (3) The range-not optimum- of environmental conditions under which the organism works. (4) The work accomplished by the organisms - whether a small segment of the stabilizing process, or a large one. Gerald A. Rohlick (2), in discussing Lackey’s article, places special emphasis on additional experimental work that should be done on the activities of protozoa and higher forms of life. The editors of Savage Works Journal (3) have summed up the problem in the following statement, “When we can answer completely the what, how, who, when and why of the organisms that populate our digestors, aerators and trickling filters, we shall simultaneously solve the problems of treatment plant design and operation that are of present concern”. In an effort to contribute something to the fund of knowledge of sanitary biology, the author undertook an investigation based on the for needs suggested by Lackey. The investigation is divided into three major parts: (l) A preliminary investigation; (2) the construction of a pure culture testing apparatus; and (3) the testing of a pure culture of organisms. The complete investigation is confined to studies of the organisms found in the aerobic phase of treatment, the precise source being the trickling filter at the Virginia Polytechnic Institute sewage disposal plant. This confinement of purpose was to allow the investigator to conduct a concentrated study of a single phase of treatment. The preliminary investigation consisted of taking frequent samples from the trickling filter and examining them under the microscope. The predominate organisms were noted and the development of pure cultures of each was attempted. The construction of a pure culture filter consisted of an attempt to duplicate in the laboratory as nearly as conditions would allow, the actual conditions that exist in the trickling filter at the plant, while at the same time observing pure culture requirements and techniques. The testing of the organisms consisted of measuring the amount of purification exerted by the organism on a synthetic sewage as it passed through the filter. The results of this investigation should answer two questions: First, can a pure culture apparatus be constructed and operated with such success that it can be used as a standard device for determining in the laboratory the degree of purification exhibited by organisms in pure culture, and Second, is it possible for a pure culture of organism to carry on the purification process. The answer to the second question will, of course, depend on a positive answer to the first question. / Master of Science
17

Performance Evaluation and Yield Determination of a Full-Scale Biological Aerated Filter

Phipps, Scott Douglas 29 March 2001 (has links)
Biological aerated filters (BAFs) are an emerging wastewater treatment technology designed for a wide range of municipal and industrial applications. BAFs utilize an inert media, either dense granular or floating, which supports biomass retention in the filter bed. BAFs offer an alternative to typical biological treatment processes; however, knowledge of the process is often limited, especially in the US market. Through various studies, process improvements were made for filter media selection, backwash protocols, and hydraulic load effects. During the summertime monitoring, seeded and unseeded nitrified effluent BOD5 samples were performed on a full-scale BAF. Discrepancies were found between seeded and unseeded samples, which warranted further investigation. Four biological treatment seeds and a commercial microbial seed were screened for appropriate seed volumes in comparison to the glucose:glutamic acid (GAA) assay, a standard for BOD5 analysis. After initial screening, a range of seed samples was applied to the BAF effluent for BOD5 and cBOD5 analysis, and to GGA and carbonaceous GGA (cGGA) analysis. A proposed seed screening protocol was developed using a ratio of measured BOD5 values in comparison to theoretical GGA standard BOD5 values. Biomass observed yield values were calculated for the full-scale BAF. Three individual mass balances were conducted to quantify the consumption of soluble COD in the filter and the mass of influent particulate matter filtered from the waste stream. Retained particulate matter is a substrate source for the biomass; however, the particles must be hydrolyzed into metabolizable monomers before being consumed by the biomass. A bench-scale BAF was designed and constructed to investigate the degree to which particle hydrolysis occurred in the full-scale system. Additionally, fluorescein diacetate was used during one of the experiments as a model particulate substrate to quantify the activity associated with hydrolytic enzymes in the bulk-liquid. Hydrolytic activity by cell-free extracellular enzymes in the bulk-liquid increased when particle substrate was present. Therefore, it appears that cell-free extracellular enzymes participate in the hydrolytic mechanism for particle degradation. Biomass observed yields were calculated for the full-scale BAF using full-scale mass balances and bench-scale particle hydrolysis experiments. / Master of Science
18

Sediment oxygen demand in coastal waters

Yung, Kam-shing., 翁錦誠. January 1994 (has links)
published_or_final_version / Civil and Structural Engineering / Doctoral / Doctor of Philosophy
19

Poly(γ-glutamic) acid (PGA) production from confectionery waste using Bacillus species

Rademeyer, Sharon January 2018 (has links)
Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018. / Approximately 9 million tonnes of food waste is generated annually in South Africa. Its treatment, including treatment of confectionery waste, is costly because of the high chemical oxygen demand (COD) loads; as a result much of this waste is sent to landfill. South Africa’s confectionery industry contributes to a significant proportion of the country’s economy. Among the confectionery waste entering landfills are defective material, expired sweets and returns. This high COD waste can create breeding grounds for pathogenic microorganisms and anaerobic methanogens, causing negative environmental impacts. Part of the Department of Science and Technology (DST) Waste Research, Development and Innovation (RD&I) roadmap initiative is to minimise waste entering landfills by identifying waste sources from which to produce value that will contribute to social and economic growth. Confectionery waste has a high sugar content which can be used for feedstock to bioprocesses. By placing this bioproduction into a waste biorefinery framework, bio-based raw materials can be used to produce competitively priced products with low environmental impact, thereby optimising remediation and value generation simultaneously. Ongoing research at the Centre for Bioprocess Engineering Research (CeBER) at the University of Cape Town has shown that a wastewater biorefinery approach can use wastewater as feedstock for the generation of products of value. Previous studies have investigated potential products of value based on nutrient loads found in wastewater as well as the nature of the product. Among the organisms selected was the Bacillus species, producing the potential product poly-γ-glutamic acid (PGA), an extracellular poly-amino acid when there is an excess of nutrients. Similarly, this product could potentially be produced from sugar-rich waste candy. The aim of this study was to explore the use of hard candy waste as a feedstock for PGA, and Bacillus licheniformis JCM 2505 was selected as it was characterised in terms of the nutrients needed. The most attractive attribute of this strain was that it did not need L-glutamic acid to synthesise PGA but could do so from sugar. L-glutamic acid is costly. Using a cheaper nitrogen alternative would make the process more cost effective. To investigate this potential, the confectionery waste was characterised to identify the nutrients, namely, sugars, organic nitrogen and key trace elements needed for cell function and PGA production. Results showed that the nitrogen content and trace element concentrations were insignificant, as it was determined that the waste consisted mostly of sucrose. This therefore had to be supplemented with a basal medium containing the supplementation needed for cell function and PGA production. The growth of B. licheniformis was profiled in Erlenmeyer shake flasks using candy waste supplemented with the basal medium, with sucrose supplemented with basal medium as a control. The results showed similar trends on candy waste and sucrose.
20

The effects of effluent discharge and concentration on streambed infiltration in the Lower Santa Cruz River

Prietto, Jacob January 2014 (has links)
Wastewater generated in the Tucson metropolitan region is conveyed to and treated at the Roger Road Wastewater Reclamation Facility (WRF) and Ina Road WRF. From 2005 to 2012, approximately 15,000 acre-feet per year of effluent was returned to the City of Tucson for additional filtration and reuse in the reclaimed water system. The remaining 48,000+ acre-feet per year of treated effluent was discharged to the Santa Cruz River, where a variable portion of the effluent infiltrates the streambed. The effluent that infiltrates the streambed contributes to recharge credits for participants invested in the Managed Underground Storage Facilities. In the effluent-dependent river, physical, chemical, and biological processes work in combination to develop a clogging layer near the streambed surface, which reduces infiltration. Previous studies have shown that large storm events have the ability to scour away the clogging layer and are the most significant processes contributing to establishing infiltration rates. Without the occurrence of large storm events, other variables such as effluent discharge and effluent concentrations affect infiltration to a lesser degree. Effluent discharge, biochemical oxygen demand, and total suspended solids are monitored and recorded daily at the outfalls of the WRFs. The parameters were investigated individually and in combination using statistical analyses to determine their correlations with streambed infiltration in the Santa Cruz River. The dry spring-early summer seasons from 2005 to 2012 were analyzed. A water balance was constructed for non-stormflow days during each time period. Evapotranspiration was calculated using riparian vegetation surveys and detailed delineations of aerial photography of the surface water and streamside herbaceous vegetation. Infiltration was derived as the residual of the water balance. At the daily time scale, correlations among variables were unobtainable due to the extremely variable characteristics of infiltration. The seasonal time scale analyses demonstrated an inverse relationship between both the effluent concentrations of biochemical oxygen demand and total suspended solids with infiltration and a direct correlation between effluent discharge and infiltration under extreme conditions. Under normal conditions, the distribution of discharge between Roger Road WRF and Ina Road WRF had a critical effect on infiltration as a result of the different deposition and erosive regimes through the Santa Cruz River.

Page generated in 0.0683 seconds