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  • 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.
311

The correlations between OSTDS sites and the pollution of the surface water bodies in Broward County

Unknown Date (has links)
Sampling data of many surface water bodies in Broward County tend to reveal abnormal levels of bacterial concentrations for total coliform, Escherichia coli and Enterococcus. Given the presence of septic systems in geohydrologically sensitive areas throughout the County, several studies (Morin 2005 and Bocca 2007) suggested a correlation in the high bacterial densities and the septic sites. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
312

From pipe dreams to tunnel vision : engineering decision-making and Sydney's sewerage system

Beder, Sharon, Science & Technology Studies (STS), UNSW January 1989 (has links)
The broad theme of this thesis is engineering decision-making. The various factors that shape technological development are investigated using the development of Sydney's sewerage system as a case study. The thesis focuses on various key decisions, past and present, including the choice of water-carriage technology for sewage collection, the selection of sewage treatment technologies, and on-going preference of engineers and bureaucrats for ocean disposal. Also covered are the legislative and regulatory mechanisms, the policies of the Sydney Water Board with regard to industrial waste disposal and the relationship between the Board and the public. A study was made of historical documents, engineering reports and papers, parliamentary debates, annual reports, minutes, newspaper reports and secondary sources and personal interviews were conducted. Various bodies of literature were referred to and used, including the books and articles on the history and sociology of engineers, the politics of expertise and public participation and the emerging discipline of science and technology studies. It is concluded that the development of Sydney's sewerage system has been shaped by social, political and economic factors and that engineers have played a pivotal role in the decisions made through their deliberate shaping of knowledge and the performance of predictions they have made for various options. The decisions made in this way have been defended against public opinion and public participation in the decision-making process has been kept to a minimum. This thesis supports the argument that technology is socially constructed, that the technical cannot be separated from the social, and that an interactive model of technological development is more appropriate than a linear, causal one. It shows that the role of power in the shaping of technology is crucial, and in particular the alliance of state and professional power that occurs in the shaping of public sector technology.
313

Assessment of public awareness of septic systems in rural Benton County

Gillett, Christopher S. 29 July 1998 (has links)
Graduation date: 1999
314

The characterisation of some South African water treatment residues and glasshouse pot experiments to investigate the potential of two residues for land disposal.

Titshall, Louis William. January 2003 (has links)
Water treatment residues (WTRs) are the by-product from the production of potable water. They consist mainly of the precipitated hydrous oxides of the treatment chemicals, and materials removed from the raw water. This study investigated the range of treatment processes and residues produced in South Africa, and two WTRs were selected for testing on selected soils and mine materials. A questionnaire was developed and sent to water treatment authorities across South Africa. Information on the treatment chemicals, dosages, volumes and current disposal practices, and a sample of WTR from each treatment plant were requested. Eleven, of 21 authorities, returned completed questionnaires, representing 37 water treatment facilities. Organic polymers were the most commonly used treatment chemical, with most plants also using lime. Other less frequently used chemicals and additives were Alz(S04)3.14I-hO, Fe2(S04)3, FeC!), sodium aluminate, activated silica, activated charcoal, CO2 and bentonite. Information given regarding residue thickening and disposal was poor. Samples from Rand Water, Umgeni Water (Midmar), Midvaal Water Company, Amatola Water and Cape Metropolitan Council (Faure) were received or collected. An additional sample from Faure was also received, representing a change in the treatment process. These samples were analysed for a range of chemical and physical characteristics. These analyses showed that the WTRs had the potential to supply some plant nutrients (Ca, Mg, Fe, S) but that metal toxicity may be a problem, in particular Mn in the Faure WTR, and that P adsorption may be severe. The samples selected to test the potential for land disposal were from Rand Water and Faure. A pot experiment tested the growth of Eragrostis tefJ, Cenchrus ciliaris and Digitaria eriantha in mixtures of Rand WTR and material from a coal mine i.e., a sandy soil material, spoil material and coal combustion ash, at rates of 0, 50, 100, 200 and 400 g kg" with a uniform fertiliser treatment applied to all mixtures. The grass was harvested on three occasions and the mean total yield (dry mass) determined, as well as nutrient uptake. The pots were leached after each harvest and the pH and electrical conductivity determined. The soil, spoil and ash were characterised and pH, EC and water retention characteristics of the mixtures determined. Growth of the grasses in the ash treatments was poor and these were terminated. Eragrostis tefJ grown in the soil showed a decrease in mean total yield with increasing WTR application rate, but yield was good up to the 200 g kg" treatment at the first harvest, declining substantially by the second harvest. In general C. ciliaris and D. eriantha grown in the soil showed a decrease in mean total yield for all harvests with increasing WTR application. The yield of E. /ejJ, grown in the spoil, increased up to 100 g kg,l WTR addition, but decreased thereafter. Digitaria eriantha showed a decrease in yield, and C. ciliaris an increase, with increasing WTR application rate , but for all treatments the differences were non-significant. The pH and EC of the leachates generally increased with increasing WTR addition. The concentration of nutrients in the grasses did not indicate any deficiencies or toxicities. As the growth of grass was poor in the ash treatments, another pot experiment was established to test the growth of two creeping grass species grown in the Rand WTR as a cover over the ash material. Cynodon dactylon and Stenotaphrum secundatum were grown in 20, 40 and 60 mm layers of Rand WTR, with and without a fertiliser treatment. Both species performed best in the 60 mm layer with fertiliser, and C. dactylon performed better than S. secundatum. The former species was more tolerant of the high pH, but both have potential as cover vegetation on the ash dumps when these are covered with Rand WTR. A further glasshouse study investigated the effect of Faure WTR mixed with a nutrient poor sandy soil on the nutrient uptake and seed yield of common dry beans (Phaseolus vulgaris). The WTR was added to the soil at 0, 50, 100, 200 and 400 g kg" each with five levels of fertiliser (0, 25, 50, 100 (recommended optimum) and 150 %). Bean pods were harvested once the plants had senesced. The number of pods and mass and number of seeds per treatment were determined. The seeds were analysed for nutrient uptake. Interveinal chlorosis and necrotic lesions were evident on cotylendonous and new leaves in the WTR treated soils, the severity of the symptoms increasing with increasing rate of WTR. Additional pots were established at the 400 g kg" rate (without fertiliser) and leaf material collected for chemical analysis. This showed that Mn toxicity was the cause, with leaf concentrations about 12 times the recommended 100 mg kg" upper limit. However, mass of bean seed was highest in the 400 g kg" Faure WTR treatment with 150 % fertiliser. Nutrient translocation to the seed seemed to be relatively consistent regardless of treatment, with little accumulation ofMn. The data collected illustrated the range of conditions and types of WTRs produced in South Africa, and that in some instances these residues have favourable characteristics for land application. The use of the Rand WTR showed that it could be applied to the spoil medium at relatively high concentrations without severely negatively impacting on grass growth, but more caution should be used when applying this material to the soil medium. While the grass did not grow in the ash treatments, it would seem that with suitable species the Rand WTR could be beneficially applied to ash material as a cover layer. The use of the Faure WTR on a sandy soil seemed to potentially improve the yield of the indicator crop, but caution should be exercised due to the possibility of Mn toxicity. The use of additional fertiliser would seem to be essential. Further research would require that field scale investigation of both WTRs be conducted, as well as further studies of applicat ion rates and techniques in laboratory and glasshouse investigations. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
315

Utenos savivaldybės vandentiekio ir nuotekų šalinimo sistemų būklė / Analysis of water supply and wastewater collection and treatment systems in Utena municipality

Leipus, Marius 16 June 2010 (has links)
Šiame magistriniame darbe yra nagrinėjama Utenos savivaldybės vandentiekio ir nuotekų šalinimo sistemų būklė. Darbo tikslas - įvertinti Utenos miesto ir rajono vandentiekio, nuotekų tinklų ir nuotekų valyklų būklę, jų efektyvumą, nustatyti, kur ir kokios šių sistemų modernizavimo priemonės yra labiausiai reikalingos. Šiame darbe pateikiamos pagrindinės Utenos savivaldybės vandentiekio ir nuotekų surinkimo ir tvarkymo sistemų problemos bei galimi jų sprendimo variantai. Nustatyta, kad išsprendus Utenos miesto ir didžiųjų gyvenviečių nuotekų valymo problemas, 70% sumažės paviršinių vandens telkinių teršimas. / This article deals with Utena municipal water supply and sewage disposal systems state. The aim of the work is to evaluate water supply and sewage treatment plant’s state in Utena city and Utena district, to evaluate their effectiveness, to identify where and how wastewater disposal systems modernization measures are most needed. The article presents the main Utena municipal sewage collection and treatment systems problems and possible solutions. The main Utenos municipality and region sewage elimination system problems are presented and also some solution versions are given.
316

The characterisation of some South African water treatment residues and glasshouse pot experiments to investigate the potential of two residues for land disposal.

Titshall, Louis William. January 2003 (has links)
Water treatment residues (WTRs) are the by-product from the production of potable water. They consist mainly of the precipitated hydrous oxides of the treatment chemicals, and materials removed from the raw water. This study investigated the range of treatment processes and residues produced in South Africa, and two WTRs were selected for testing on selected soils and mine materials. A questionnaire was developed and sent to water treatment authorities across South Africa. Information on the treatment chemicals, dosages, volumes and current disposal practices, and a sample of WTR from each treatment plant were requested. Eleven, of 21 authorities, returned completed questionnaires, representing 37 water treatment facilities. Organic polymers were the most commonly used treatment chemical, with most plants also using lime. Other less frequently used chemicals and additives were A12(SO4)3.14H2O, Fe2(SO4)3, FeC1), sodium aluminate, activated silica, activated charcoal, CO2 and bentonite. Information given regarding residue thickening and disposal was poor. Samples from Rand Water, Umgeni Water (Midmar), Midvaal Water Company, Amatola Water and Cape Metropolitan Council (Faure) were received or collected. An additional sample from Faure was also received, representing a change in the treatment process. These samples were analysed for a range of chemical and physical characteristics. These analyses showed that the WTRs had the potential to supply some plant nutrients (Ca, Mg, Fe, S) but that metal toxicity may be a problem, in particular Mn in the Faure WTR, and that P adsorption may be severe. The samples selected to test the potential for land disposal were from Rand Water and Faure. A pot experiment tested the growth of Eragrostis teff, Cenchrus ciliaris and Digitaria eriantha in mixtures of Rand WTR and material from a coal mine i.e., a sandy soil material, spoil material and coal combustion ash, at rates of 0, 50, 100, 200 and 400 g kg-1 with a uniform fertiliser treatment applied to all mixtures. The grass was harvested on three occasions and the mean total yield (dry mass) determined, as well as nutrient uptake. The pots were leached after each harvest and the pH and electrical conductivity determined. The soil, spoil and ash were characterised and pH, EC and water retention characteristics of the mixtures determined. Growth of the grasses in the ash treatments was poor and these were terminated. Eragrostis teff grown in the soil showed a decrease in mean total yield with increasing WTR application rate, but yield was good up to the 200 g kg-1 treatment at the first harvest, declining substantially by the second harvest. In general C. ciliaris and D. eriantha grown in the soil showed a decrease in mean total yield for all harvests with increasing WTR application. The yield of E. teff, grown in the spoil, increased up to 100 g kg-1 WTR addition, but decreased thereafter. Digitaria eriantha showed a decrease in yield, and C.ciliaris an increase, with increasing WTR application rate, but for all treatments the differences were non-significant. The pH and EC of the leachates generally increased with increasing WTR addition. The concentration of nutrients in the grasses did not indicate any deficiencies or toxicities. As the growth of grass was poor in the ash treatments, another pot experiment was established to test the growth of two creeping grass species grown in the Rand WTR as a cover over the ash material. Cynodon dactylon and Stenotaphrum secundatum were grown in 20, 40 and 60 mm layers of Rand WTR, with and without a fertiliser treatment. Both species performed best in the 60 mm layer with fertiliser, and C. dactylon performed better than S. secundatum. The former species was more tolerant of the high pH, but both have potential as cover vegetation on the ash dumps when these are covered with Rand WTR. A further glasshouse study investigated the effect of Faure WTR mixed with a nutrient poor sandy soil on the nutrient uptake and seed yield of common dry beans (Phaseolus vulgaris). The WTR was added to the soil at 0, 50, 100, 200 and 400 g kg-1 each with five levels of fertiliser (0, 25, 50, 100 (recommended optimum) and 150 %). Bean pods were harvested once the plants had senesced. The number of pods and mass and number of seeds per treatment were determined. The seeds were analysed for nutrient uptake. Interveinal chlorosis and necrotic lesions were evident on cotylendonous and new leaves in the WTR treated soils, the severity of the symptoms increasing with increasing rate of WTR. Additional pots were established at the 400 g kg-1 rate (without fertiliser) and leaf material collected for chemical analysis. This showed that Mn toxicity was the cause, with leaf concentrations about 12 times the recommended 100 mg kg-1 upper limit. However, mass of bean seed was highest in the 400 g kg-1 Faure WTR treatment with 150 % fertiliser. Nutrient translocation to the seed seemed to be relatively consistent regardless of treatment, with little accumulation of Mn. The data collected illustrated the range of conditions and types of WTRs produced in South Africa, and that in some instances these residues have favourable characteristics for land application. The use of the Rand WTR showed that it could be applied to the spoil medium at relatively high concentrations without severely negatively impacting on grass growth, but that more caution should be used when applying this material to the soil medium. While the grass did not grow in the ash treatments, it would seem that with suitable species the Rand WTR could be beneficially applied to ash material as a cover layer. The use of the Faure WTR on a sandy soil seemed to potentially improve the yield of the indicator crop, but caution should be exercised due to the possibility of Mn toxicity. The use of additional fertiliser would seem to be essential. Further research would require that field scale investigation of both WTRs be conducted, as well as further studies of application rates and techniques in laboratory and glasshouse investigations. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
317

Ecological and economic aspects of treating vegetable oil industrial effluent at Darvill Wastewater Works in Pietermaritzburg.

Moodley, Shomenthree. January 1997 (has links)
The dissertation analyses the economic and ecological aspects of Darvill Waste Water Works (WWW) through key indicators from Sustainable Development Records (SDR). The SDR study identifies disturbances caused by large concentrations of soap, oil and grease (SaG), therefore a framework of proposed solutions to dealing with these problems has also been investigated. The first component of the study highlights the importance of adequate indicators. Key indicators provide important information that is useful to management and policy makers. The SDR used to analyse the DarvillWWW in Pietermaritzburg provides relevant information for the management of Darvill WWW and Umgeni Water (UW), the City Council and the Department of Water Affairs and Forestry (DWAF). According to the SDR model the Works is identified as a service providing social institution. The operation of this institution affects the community of Pietermaritzburg as well as the surrounding natural environment. SDR uses the key indicators of effectiveness, Thrift and Margin to analyse the economic and ecological impacts of the service provided.The study incorporates relevant data for Darvill WWW during 1993- 1996. Effectiveness measures the degree of compliance with national water quality standards as set out by the DWAF. Compliance of the following variables, E.coli, Chlorine, Soluble Reactive Phosphate (SRP), Total Suspended Solids (TSS), Conductivity, Chemical Oxygen Demand (COD) and Ammonia were investigated. These variables produce varying trends. Increasing compliance is linked to improved plant efficiency while decreasing compliance is linked to the poor quality of industrial effluent. Industrial effluent containing large concentrations of SOG is a particular problem. Thrift measures the costs of operating the Works in terms of energy, chemicals, labour and capital. Overall financial, energy and labour thrift declined while chemical thrift increased. Increasing chemical thrift is due to the reduced consumption of chemicals as a result of a greater reliance on the process of biological phosphate removal. Decreasing thrift is related to increased costs of capital, energy and labour due to the deteriorating quality of vegetable oil effluent. Margin measures the deviation of non-complying samples from water quality standards. Analysis of the data produced varying trends. The following variables were analysed, E.coli, Chlorine, SRP, TSS, Conductivity, COD and Ammonia. Marginal difference is studied in an attempt to analyse those samples which do not comply with national standards. Deteriorating quality of industrial effiuent seems to be the reason for deviation from the standards. Chemical margin was also studied for the period between 1993-1996. Chemical margin is a comparison between the value of sludge produced and the cost of chemicals used to produce the sludge. The SDR study highlights deteriorating quality of industrial effluent as a cause for concern to Darvill WWW. Proposed management options are investigated to provide a workable solution. The second part of the study investigates alternate options for handling wet industrial effluent from the vegetable oil industries. These industries were identified as the source of large concentrations of SOG that were entering the Works which impacts negatively on the operational capacity, thereby increasing operating costs and decreasing the quality of the service provided. Vegetable oil industries were found guilty of discharging industrial effluent that did not meet the City standards into the sewers, they were also charged with illegal dumping into rivers. The study identified the interested and affected parties and alternate solutions were proposed to the problems. Interested and affected parties include UW, Pietermaritzburg City Council, DWAF. Some of the aspects that were investigated include the local industrial tariff, the drainage By-laws, national legislation, the "polluter pays" principle and the principle of pollution prevention. Economic incentives using economic instruments were reviewed. These include ecotaxes such as marketable/tradable permits and pollution charges. These instruments may allow for more equitable charges thereby promoting the "polluter pays" principle. The use of these instruments may be able to achieve a workable solution but further investigations are necessary. SDR analysis indicates that Darvill WWW seems to be effectively treating wastewater but operating costs are increasing in order to achieve compliance. These costs are being unfairly borne by the City ratepayers and UW and a more equitable situation is necessary. / Thesis (M.Env.Dev.)-University of Natal, Pietermaritzburg, 1997.
318

Impact of microbial and physico-chemical qualities of treated wastewater effluent on receiving water bodies in Durban.

Naidoo, Shalinee. 11 September 2014 (has links)
Increase in magnitude of the global freshwater crisis together with the constantly changing demographics, hydrological variability and rapid urbanization will allow for continuous over exploitation of existing water resources, in an attempt to satisfy the rising socioeconomic demands. Increasing pressure on existing wastewater treatment plants, together with inefficient hygiene practices have exacerbated the nutrient and microbiological loads constantly entering surrounding water systems. This, coupled with the use of outdated guidelines has resulted, not only in an increase in waterborne related diseases but also an increase in waterborne-disease-related deaths. The current study investigated the physicochemical and microbiological quality of treated effluent from two independent wastewater treatment plants as well as their impact on the receiving watershed within Durban, South Africa over a one year period. Microbiological and physicochemical profiles were determined using standard methods whilst conventional PCR was used for the seasonal detection of human enteric viruses. Monthly variations were observed for all parameters with eight and six out of 12 month samples exhibiting increases in turbidity at the discharge point for the NWWTP and NGTW respectively, relative to before chlorination. Similarly, increases in nitrate and phosphate levels at the discharge point were also noted with the highest being recorded during December (215.23%) and September (12.21%) respectively. Temperature profiles ranged between 12 – 26 °C and 12.7 – 26 °C for the NWWTP and receiving Umgeni River whilst for the NGTW and receiving Aller River, it ranged between 16.5 – 26 °C and 12 – 25.7 °C respectively. Seasonal averages revealed relatively high COD values downstream of the Umgeni River during winter (263.22 mg/l) and spring (177.93 mg/l). Eight out of twelve samples exhibited increases in turbidity at the discharge point for the NWWTP with the highest values obtained during April (76.43 NTU). Significant positive correlations (p ≤ 0.05) were observed upstream and downstream of the Umgeni River between temperature and BOD (r = 0.624); turbidity (r = 0.537); TDS (r = 0.437); TSS (r = 0.554) and DO (r = 0.516). Percentage reduction of bacterial indicators at the discharge point ranged between 0.52 – 100% and 41.56 – 100% across the sampling period for the NWWTP and NGTW, respectively. Treated effluent from both plants did not meet the required guidelines, with a 100% reduction in the faecal coliform load being detected only during October 2012 for both plants. In addition, higher levels of indicator bacteia were observed at the discharge point for the NWWTP during February 2013 with observed counts (in CFU/ml) as high as 12.27 x 103; 6.61 x 103; 2.99 x103; 1.6 x 103 and 1.17 x103 for total coliforms, E.coli, faecal coliforms, faecal streptococci and enterococci, respectively. Similarly, higher levels of both somatic and F-RNA bacteriophages were detected during April (106.67 PFU/ml), May (309.33 PFU/ml). June (346.67 PFU/ml) and August (126.67 PFU/ml) compared to samples collected before chlorination for the NWWTP. Enteroviruses were detected in 100% of unchlorinated final effluent samples, 87.5% of chlorinated final effluent and 93.75% of receiving river samples whilst human adenoviruses were detected in 50% of final effluent samples before chlorination, 62.5% in samples collected at the discharge point and 62.5% of river water samples. This study revealed that whilst the independent treatment plants monitored, exhibited effluent qualities that met acceptable standards for some parameters such as pH and temperature, the effluent quality fell short of other standard requirements. Ensuring efficient surveillance and management of existing treatment plants coupled with guideline revision and monitoring compliance is imperative in preventing further risk of pollution to both the environment and human health. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2013.
319

Sewage diversion and the coral reef community of Kane‘ohe Bay, Hawai‘i: 1970- 1990

Evans, Christopher W 12 1900 (has links)
The coral reefs of Kane'ohe Bay, on the windward coast of O'ahu, Hawai'i, have changed markedly over the last half century. Some of the most spectacular coral reefs in Hawai'i were reported from Kane'ohe Bay in the late 1800's and early 1900's, but with the beginning of extensive military dredge and fill operations during the World War IT era, conditions in the bay began to change dramatically. After the War, rapid urbanization of the area began and conditions in the bay continued to decline until pressure from the public and scientific community led to the diversion of the large sewage discharges in the southeast lagoon to a newly built deep ocean outfall outside the bay in 1977-1978. Although conditions temporally improved, recent surveys indicate that current conditions in the bay are not as favorable as expected. This study provides a time series analysis of changes in coral and algae cover in Kane'ohe Bay based upon a series of coral reef surveys conducted throughout the bay in 1970171, 1983, and 1990. Beginning in 1970171, conditions in the bay were highly degraded and scientists speculated that eutrophication and sedimentation, as a result of urbanization and construction, were the primary cause of an observed decline in lagoon corals communities in the southeast lagoon and an explosive growth of the green "bubble algae", Dictyosphaeria cavemosa, which was smothering corals in the middle lagoon. In . 1983, six years after major sewage discharges were diverted from the bay, surveys indicated dramatic improvements in water quality and the reefs showed signs of recovery. D. cavemosa algae levels, associated with earlier nutrient pollution, plummeted to less than twenty percent of their former abundance levels and coral cover increased by over two hundred percent. Although it was predicted that the coral reefs of Kane'ohe Bay would continue to recover, surveys in 1990 indicate that coral recovery slowed or ceased and the growth of the green "bubble algae", D. cavemosa, more than doubled compared to 1983 levels. In addition to the failure of the t~o dominant coral species Porites compressa and Montipora capitata to continue to recover, almost all of the less common coral species including Pocillopora damicomis, Fungia scutaria, Cyphastrea ocellina, and some others, showed significant declines in reef cover. Although this study was not able to detennine the exact causes of the observed changes in Kane'ohe Bay, it is suggested that high nutrient inputs provided favorable conditions for the changes in coral and algae cover. High nutrient levels are thought to have been derived from a number of sources including chronic sewage pollution, increased sedimentation from runoff, and reef kills associated with acute but large episodes of freshwater runoff. Some of these nutrient inputs may have been the result of non-point source and point source sewage pollution derived from leaky sewer lines, cesspool and septic tank discharges, commercial tour and recreational boat waste discharges, and periodic sewage bypasses from municipal wastewater treatment plants and sewage pump stations. Other nutrients may have been derived from increased sedimentation following extensive land clearance, land development, and highway construction. Additional factors may include a decrease in herbivorous fish species owing to over fishing and the ability of D. cavemosa algae to concentrate nutrients from underlying substrates and excretion from infaunal organisms. Other factors such as increased nutrient recycling from the sediments, possible increased nitrogen fixation from reefs, and natural fluctuations in relative species abundances may also be responsible for some of the observed changes in coral reef community structure. Although rare, the largest nutrient fluxes followed the catastrophic freshwater reef-kill events caused by severe rainstorms in conjunction with low tides and low wind conditions in 1965 and 1987-1988. Although the cause and effect relationship is still uncertain, the highest levels of Dictyosphaeria cavemosa algae ever recorded in Kane'ohe Bay occurred in the years following these storm events. Results of this study indicate that further research is needed to monitor ongoing conditions in the bay and determine what is preventing the reef ecosystem from returning to its former more pristine condition. Because water quality parameters generally remained the same or improved compared to previous polluted conditions, it is suggested that current measures of water quality are not reliable in forewarning against coral reef degradation in Kane'ohe Bay. Although a reduction in all future development in and around the bay would probably help maintain environmental conditions at the status quo, additional regulations and enforcement may be needed to help reduce disturbances caused by existing land and water use. It is suggested that a reduction in nutrient inputs to the bay would be beneficial to reef corals. Recommendations made by the Kane'ohe Bay Task Force outlined in the Kane'ohe Bay Master Plan should serve as a model and be implemented as soon as possible. Continuing assessment of the Kane'ohe Bay coral reef ecosystem and surrounding watershed will then need to be made on a regular basis to ensure that further degradation of the reefs is not occurring. / Thesis (M. A.)--University of Hawaii at Manoa, 1995. Includes bibliographical references (leaves 166-175).
320

The use of treated effluent for agricultural irrigation in the Bottelary River area: Effluent quality, farmers perception and potential extent.

Rui, Li January 2005 (has links)
The Bottelary River area is located in a Mediterranean climate region, where the agricultural sector plays an important role. During the dry summer season, there is not enough precipitation to meet the agricultural irrigation requirements. Some farmers extract river water which is practically the final treated effluent from the Scottsdene Wastewater Treatment Works to irrigate crops. This research investigated the use of treated effluent for agricultural irrigation in this area, particularly focused on the effluent quality, farmers perception, and the potential extent.

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