• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 44
  • 8
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 61
  • 61
  • 33
  • 28
  • 18
  • 16
  • 15
  • 12
  • 12
  • 11
  • 11
  • 10
  • 10
  • 8
  • 8
  • 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.
31

Development of Transitional Settling Regimen Parameters to Characterize and Optimize Solids-liquid Separation Performance

Mancell-Egala, Abdul Salim 20 September 2016 (has links)
Novel settling characteristic metrics were developed based on the fundamental mechanisms of coagulation, flocculation, and settling. The settling metrics determined parameters that are essential in monitoring and optimizing the activated sludge process without the need for expensive or specialized equipment. Current settling characteristic measurements that don't require specialized instruments such as sludge volume index (SVI) or initial settling velocity (ISV), have no fundamental basis in solid-liquid separation and only indicate whether settling is good or bad without providing information as to limitations present in a sludge matrix. Furthermore, the emergence of aerobic granulation as a potential pathway to mitigate solid-separation issues further stresses the need for new settling characteristic metrics to enable integration of the new technology with the current infrastructure. The granule or intrinsic aggregate fraction in different types was of sludge was quantified by simulating different surface overflow rates (SOR). The technique named Intrinsic Settling Classes (ISC) was able to separate granules and floc by simulating high SOR values due to the lack of a flocculation time needed for granules. The method had to be performed in a discrete settling environment to characterize a range of flocculation behavior and was able to classify the granular portion of five different types of sludge. ISC was proven to accurately (±2%) determine the granule fraction and discrete particle distribution. The major significance of the test is its ability to show if a system is producing particles that will eventually grow to become granules. This methodology proved to be very valuable in obtaining information as to the granular fraction of sludge and the granular production of a system. Flocculent settling (stokesian) was found to be predominant within ideally operating clarifiers, and the shift to 'slower' hindered settling (non-stokesian) causes both failure and poor effluent quality. Therefore, a new metric for settling characteristics was developed and classified as Limit of Stokesian Settling (LOSS). The technique consisted of determining the total suspended solids (TSS) concentration at which mixed liquor settling characteristics transition from stokesian to non–stokesian settling. An image analytical technique was developed with the aid of MATLAB to identify this transition. The MATLAB tool analyzed RGB images from video, and identified the presence of an interface by a dramatic shift in the Red indices. LOSS data for Secondary activated-sludge systems were analyzed for a period of 60 days at the Blue Plains Advanced Wastewater Treatment Plant. LOSS numbers collected experimentally were validated with the Takacs et al. (1991) settling model. When compared to flux curves with small changes in the sludge concentration matrix, LOSS was found to be faster at characterizing the hindered settling velocity and was less erratic. Simple batch experiments based on the critical settling velocity (CSV) selection were used as the basis for the development of two novel parameters: threshold of flocculation/flocculation limitation (TOF/a), and floc strength. TOF quantified the minimum solids concentration needed to form large flocs and was directly linked to collision efficiency. In hybrid systems, an exponential fitting on a CSV matrix was proposed to quantify the collision efficiency of flocs (a). Shear studies were conducted to quantify floc strength. The methods were applied to a wide spectrum of sludge types to show the broad applicability and sensitivity of the novel methods. Three different activated sludge systems from the Blue Plains AWWTP were monitored for a 1 year period to explore the relationship between effluent suspended solids (ESS) and activated sludge settling and flocculation behavior. Novel metrics based on the transitional solids concentration (TOF, and LOSS) were also collected weekly. A pilot clarifier and settling column were run and filmed to determine floc morphological properties. SVI was found to lose sensitivity (r < 0.20) when characterizing ISV above a hindered settling rate of 3 m h-1. ISV and LOSS had a strong correlation (r = 0.71), but ISV was subject to change, depending on the solids concentration. Two sludge matrix limitations influencing ESS were characterized by transition concentrations; pinpoint floc formation, and loose floc formation. Pinpoint flocs had TOF values above 400 mg TSS L-1; loose floc formation sludge had TOF and LOSS values below 400 mg TSS L-1 and 900 mg TSS L-1, respectively. TOF was found to correlate with the particle size distribution while LOSS correlated to the settling velocity distribution. The use of both TOF and LOSS is a quick and effective way to characterize limitations affecting ESS. / Ph. D.
32

The biological sulphate removal process

Greben, Harma 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: South Africa is one of the world's major coal producers, resulting in the second highest foreign exchange earner for South Africa. However, the mining industry contributes negatively to (ground) water pollution, due to the formation of acid mine drainage (AMD). AMD originates from the bacterial oxidation (Thiobacillus ferrooxidans) of pyrite (FeS) and contains high levels of sulphate and metals. Sulphate rich waters can be treated applying the biological sulphate removal technology. This study concentrated on biologically removing sulphate from synthetic feed- and mine water, using the single-stage completely-mixed reactor system. The advantage of using this reactor system is that except for removing sulphate from about 2000 to less than 200 mg/t', it can also partly biologically remove the formed sulphides. It was established that both ethanol and sugar can be used, as the carbon and energy source, however ethanol is more cost effective than sugar. Ethanol dosage and Hydraulic Retention Time (HRT) studies were undertaken to investigate at what concentration, the highest sulphate and sulphide removal rates were achieved. It was found that the highest sulphate reduction rates were obtained when using 1mf ethanol/f feed and that the removal rates were dependent on the HRT: the lower the HRT, the higher the sulphate reduction rate. The highest sulphide oxidation rate was achieved at the HRT of 6 h. It was, furthermore shown that the single stage completely-mixed reactor system could successfully be used to remove sulphate from Schoongezicht mine effluent, not only removing the sulphate, but also most of the metals, thereby increasing the mine effluent pH from 2.5 to 7. The conclusion of this study was that a completely-mixed reactor system, as described in this thesis, can successfully be applied to treating acid mine drainage using ethanol (1 m.e etanol/f feed water) as the carbon and energy source at a hydraulic retention time as low as 4 hours. This technology has great potential for pilot- and full-scale treatment of sulphate rich effluents such as acid mine drainage. / AFRIKAANSE OPSOMMING: Suid Afrika is een van die vemaamste steenkool produseerders in die wereld, terwyl die uitvoer van steenkool die land se tweede hoogste verdiener is van buitelandse valuta. Ongelukkig dra hierdie industrie ook by tot die besoedeling van (grond) water, veral vanwee die vorrning van suur myn afloop. Bakteriese oksidasie (deur Thiobacillus ferrooxidansy van piried (FeS) is hoofsaaklik verandwoordelik vir die vorrning van suur myn afloop bevattende hoe konsentrasies van sulfaat en metale. . Die toepassing van biologiese sulfaatverwyderingsprosesse vir die behandeling van sulfaatryke waters is vroeer gedemonstreer. Die doel van hierdie studie was om 'n enkel-stadium reaktor met volledige vermenging te evalueer en te optimiseer om toegepas te word vir die biologiese verwydering van sulfaat vanuit sinteties bereide, sowel as mynwater. Hierdie reaktor is in staat om sulfaat te verwyder vanaf vlakke van ~ 2000 tot minder as 200 mg/P. 'n Verdere voordeel gepaard met die gebruik van hierdie reaktor is dat die sulfied wat gevorm word tydens sulfaatreduksie, gedeeltelik verwyder word deur die oksidasie daarvan na So. Die resultate wat behaal is in hierdie studie het aangedui dat beide etanol en suiker gebruik kan word as die koolstof en energiebron, terwyl etanol meer koste-effektief aangewend kon word. In teenstelling was metanol nie 'n geskikte koolstofbron vir sulfaatverwydering nie. Eksperimente is daarvolgens uitgevoer om toestande van optimum etanoldosering en hidroliese retensietyd (HRT) vir maksimum sulfaat- en sulfiedverwydering te bepaaJ. Die hoogste reduksie tempo's was verkry met 'n toediening van 1 mP etanol/f invloei, en die effektiwiteit van verwydering was afhanklik van HRT. Hoe laer die HRT, hoe hoer die tempo van sulfaatverwydering. Die beste sulfaatverwyderingstempo was behaal teen 'n HRT van 6 uur. Die resultate het verder aangetoon dat die enkel-stadium reaktor met volledige vermenging in staat was om sulfaat effektief te verwyder, en die pH te verhoog vanaf na 2.5 tot 7, in mynuitvloeisels van 'n plaaslike steenkoolmyn. Die gevolgtrekking uit hierdie werk is dat 'n volledig-gemengde reaktorstelsel, soos beskryf in die huidige studie, geskik is vir die suksesvolle behandeling van suur mynafloopwater met die gebruik van etanol (l mflP toevoerwater) as koolstof- en energiebron by 'n hidrouliese retensietyd tot so laag as 4 uur. Die tegnologie het groot toepassingspotensiaal vir volskaalse behandeling van sulfaatryke afloopwaters soos by. suur mynafloop.
33

Ecotoxicological study on effluent from electroplating industry =: 電鍍工業廢水之生態毒理硏究. / 電鍍工業廢水之生態毒理硏究 / Ecotoxicological study on effluent from electroplating industry =: Dian du gong ye fei shui zhi sheng tai du li yan jiu. / Dian du gong ye fei shui zhi sheng tai du li yan jiu

January 2002 (has links)
by Wong Suk Ying. / Thesis submitted in: November 2001. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 144-157). / Text in English; abstracts in English and Chinese. / by Wong Suk Ying. / Acknowledgments --- p.i / Abstract --- p.ii / Contents --- p.v / List of Figures --- p.x / List of Tables --- p.xvi / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Electroplating Industry in Hong Kong --- p.1 / Chapter 1.1.1 --- Typical stages in electroplating process --- p.1 / Chapter 1.1.1.1 --- Pre-treatment --- p.1 / Chapter 1.1.1.2 --- Electroplating --- p.3 / Chapter 1.1.1.3 --- Post-treatment --- p.3 / Chapter 1.1.2 --- Typical characteristics of wastestreams from electroplating industry --- p.3 / Chapter 1.2 --- Chemical Specific Approach against Toxicity Based Approach --- p.6 / Chapter 1.3 --- Ecotoxicological Study on Electroplating Effluent --- p.7 / Chapter 1.4 --- Toxicity Identification Evaluation --- p.8 / Chapter 1.4.1 --- Phase I: Toxicity Characterization --- p.9 / Chapter 1.4.2 --- Phase II: Toxicity Identification --- p.10 / Chapter 1.4.3 --- Phase III: Toxicity Confirmation --- p.12 / Chapter 1.5 --- Toxicity Identification Evaluation on Electroplating Effluent --- p.14 / Chapter 1.6 --- Selection of Organisms for Bioassays --- p.15 / Chapter 1.6.1 --- Organism used for toxicity identification evaluation --- p.17 / Chapter 2. --- OBJECTIVES --- p.20 / Chapter 3. --- MATERIALS AND METHODS --- p.21 / Chapter 3.1 --- Source of Samples --- p.21 / Chapter 3.2 --- Toxicity Identification Evaluation: Phase I Baseline Toxicity Test --- p.21 / Chapter 3.2.1 --- Microtox® test --- p.23 / Chapter 3.2.2 --- Growth inhibition test of a marine unicellular microalga Chlorella pyrenoidosa CU-2 --- p.25 / Chapter 3.2.3 --- Survival test of a marine amphipod Hylae crassicornis --- p.28 / Chapter 3.2.4 --- Survival test of a marine shrimp juvenile Metapenaeus ensis --- p.31 / Chapter 3.3 --- Toxicity Identification Evaluation: Phase I Toxicity Characterization --- p.34 / Chapter 3.3.1 --- pH adjustment filtration test --- p.35 / Chapter 3.3.2 --- Aeration test --- p.36 / Chapter 3.3.3 --- C18 solid phase extraction test --- p.37 / Chapter 3.3.4 --- EDTA chelation test --- p.38 / Chapter 3.3.5 --- Graduated pH test --- p.40 / Chapter 3.4 --- Toxicity Identification Evaluation: Phase II Toxicity Identification --- p.41 / Chapter 3.4.1 --- Filter extraction test --- p.41 / Chapter 3.4.2 --- Total metal content analysis --- p.42 / Chapter 3.5 --- Toxicity Identification Evaluation: Phase III Toxicity Confirmation --- p.43 / Chapter 3.5.1 --- Chemicals --- p.44 / Chapter 3.5.2 --- Mass balance test --- p.44 / Chapter 3.5.3 --- Spiking test --- p.44 / Chapter 4. --- RESULTS --- p.46 / Chapter 4.1 --- Chemical Characteristics of the Electroplating Effluent Samples --- p.46 / Chapter 4.2 --- Toxicity Identification Evaluation: Phase I Baseline Toxicity --- p.46 / Chapter 4.2.1 --- Toxicity of electroplating effluent samples on Microtox® test --- p.46 / Chapter 4.2.2 --- Toxicity of electroplating effluent samples on growth inhibition test of microalga Chlorella pyrenoidosa CU-2 --- p.46 / Chapter 4.2.3 --- Toxicity of electroplating effluent samples on survival test of amphipod Hyale crassicornis --- p.52 / Chapter 4.2.4 --- Toxicity of electroplating effluent samples on survival test of shrimp juvenile Metapenaeus ensis --- p.52 / Chapter 4.3 --- Toxicity Identification Evaluation: Phase I Toxicity Characterization --- p.52 / Chapter 4.3.1 --- Toxicity Characterization of electroplating effluent samples using Microtox® test --- p.56 / Chapter 4.3.2 --- Toxicity Characterization of electroplating effluent samples using microalgal growth inhibition test of Chlorella pyrenoidosa CU-2 --- p.59 / Chapter 4.3.3 --- Toxicity Characterization of electroplating effluent samples using survival test of amphipod Hyale crassicornis --- p.65 / Chapter 4.3.4 --- Toxicity Characterization of electroplating effluent samples using survival test of shrimp juvenile Metapenaeus ensis --- p.68 / Chapter 4.4 --- Toxicity Identification Evaluation: Phase II Toxicity Identification --- p.73 / Chapter 4.4.1 --- Metal analysis on the electroplating effluents --- p.75 / Chapter 4.4.2 --- Effect of filter extraction test on toxicity recovery of the electroplating effluent samples --- p.75 / Chapter 4.4.2.1 --- Microtox® test --- p.75 / Chapter 4.4.2.2 --- Growth inhibition test of microalga Chlorella pyrenoidosa CU-2 --- p.75 / Chapter 4.4.2.3 --- Survival test of amphipod Hyale crassicornis --- p.81 / Chapter 4.4.2.4 --- Survival test of shrimp juvenile Metapenaeus ensis --- p.90 / Chapter 4.4.3 --- Effect of filter extraction test on metal ions recovery of the electroplating effluent samples --- p.90 / Chapter 4.5 --- Toxicity Identification Evaluation: Phase III Toxicity Confirmation --- p.96 / Chapter 4.5.1 --- Mass balance test results on Microtox® test --- p.96 / Chapter 4.5.2 --- Mass balance test results on survival test of amphipod Hyale crassicornis --- p.104 / Chapter 4.5.3 --- Spiking test results on Microtox® test --- p.106 / Chapter 4.5.4 --- Spiking test results on survival test of amphipod Hyale crassicornis --- p.113 / Chapter 5. --- DISCUSSION --- p.118 / Chapter 5.1 --- Toxicity Identification Evaluation: Phase I Baseline Toxicity --- p.118 / Chapter 5.2 --- Toxicity Identification Evaluation: Phase I Toxicity Characterization --- p.119 / Chapter 5.2.1 --- pH adjustment filtration test --- p.119 / Chapter 5.2.2 --- Aeration test --- p.120 / Chapter 5.2.3 --- C18 solid phase extraction test --- p.120 / Chapter 5.2.4 --- EDTA chelation test --- p.120 / Chapter 5.2.5 --- Graduated pH test --- p.121 / Chapter 5.3 --- Toxicity Identification Evaluation: Phase II Toxicity Identification --- p.122 / Chapter 5.3.1 --- Metal analysis on the electroplating effluents --- p.122 / Chapter 5.3.2 --- Effect of filter extraction test on toxicity and metal ions recovery of the electroplating effluent samples --- p.123 / Chapter 5.3.3 --- Comparison between the concentrations of the metal ions in the electroplating effluent samples with the Technical Memorandum on standards for effluent discharged --- p.124 / Chapter 5.3.4 --- Comparison between the concentrations of the metal ions in the electroplating effluent samples with the toxicity of the metal ions reported in the literature --- p.124 / Chapter 5.3.4.1 --- Microtox® test --- p.126 / Chapter 5.3.4.2 --- Microalga --- p.126 / Chapter 5.3.4.3 --- Amphipod --- p.126 / Chapter 5.3.4.4 --- Shrimp --- p.126 / Chapter 5.4 --- Toxicity Identification Evaluation: Phase III Toxicity Confirmation --- p.131 / Chapter 5.4.1 --- Mass balance test on Microtox® test --- p.132 / Chapter 5.4.2 --- Mass balance test on survival test of amphipod Hyale crassicornis --- p.133 / Chapter 5.4.3 --- Spiking test on Microtox® test --- p.133 / Chapter 5.4.4 --- Spiking test on survival test of amphipod Hyale crassicornis --- p.134 / Chapter 5.5 --- Toxicity of the Metal Ions Identified as the Toxicants in the Electroplating Effluent --- p.135 / Chapter 5.5.1 --- Copper --- p.135 / Chapter 5.5.2 --- Nickel --- p.137 / Chapter 5.5.3 --- Zinc --- p.138 / Chapter 5.6 --- Summary --- p.140 / Chapter 6. --- CONCLUSIONS --- p.142 / Chapter 7. --- REFERENCES --- p.144 / Chapter 7.1 --- APPENDIXES --- p.158
34

Estudo da adsorção do corante reativo blue 19 por lama vermelha ativada por tratamento químico e térmico /

Souza, Kelli Cristina de. January 2012 (has links)
Orientador: Maria Lucia Pereira Antunes / Banca: Antonio Carlos Vieira Coelho / Banca: Fabiano Tomazini da Conceição / Resumo: A indústria têxtil é responsável pela geração de efluentes que, normalmente, apresentam um nível indesejável de coloração devido à etapa de tingimento, onde utilizam-se corantes que, quando lançados nos corpos d'água, levam à alteração de sua qualidade e ocasionam efeitos danosos ao meio ambiente e à saúde humana. Em vista disso, este trabalho teve como objetivo utilizar a lama vermelha, resíduo gerado em larga escala na produção de alumínio, como meio adsorvedor do corante Reativo Blue 19, o qual possui grande aplicação industrial e características que dificultam sua remoção em solução aquosa por meio de tratamentos convencionais. Sendo assim, optou-se por ativar a lama vermelha através de tratamento químico (água do mar, nitrato de cálcio e peróxido de hidrogênio) e térmico (400ºC e 500ºC), visando identificar a interferência desses tratamentos no aumento de sua capacidade adsortiva. Para isso, foi realizada a caracterização das amostras de lama vermelha através da determinação do pH, condutividade elétrica, ponto de carga zero (PCZ) difração de raios - x (DRX) e área superficial específica, sendo que a análise granulométrica foi realizada somente para a lama vermelha "in natura". Em seguida, visando determinar a capacidade adsortiva da lama vermelha ativada, foram construídas isortermas de adsorção, linearizadas segundo os modelos de Langmuir e Freundlich. Para efeito de comparação, a mesma metodologia foi aplicada ao carvão ativado visando determinar sua capacidade em adsorver o mesmo corante. Foi realizado o estudo da cinética de reação através dos modelos pseudo-segunda ordem, onde todas as amostras obedeceram ao modelo de pseudo - segunda ordem. Os resultados mostraram-se bastante promissores, sendo que a lama vermelha ativada por nitrato de cálcio a 500ºC apresentou uma... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The textile industry is responsible for the generation of effluents usually have an undersirable level of staining due to the step of dyeing, which is used dye which, when thrown into water bodies, leading to alteration of its quality and cause harmful effects the environment and human health. As a result, this study aimed to use the red mud, waste generated on a large scale in the production of aluminum, such as through adsorption of the dye Reactive Blue 19, which has a large industrial application and characteristics that hinder its removal in solution Aqueous by conventional treatments. Therefore, we chose to activate the red mud by chemical treatment (seawater, calcium nitrate and hydrogen peroxide) and thermal (400º C and 500º C) in order to identify the influence of these treatment in increasing its adsorption capacity. For this, we performed the characterization of samples of samples of red mud by determining the pH, electrical conductivity, point of zero charge (PZC) - ray diffraction (XRD) and specific surface area, and the particle size analysis was performed only for red mud "in nature". Then, to determine the adsorptive capacity of activated red mud, adsorption isotherms were constructed, according to the linearized Langmuir and Freundlich models. For comparison, the same methodology was applied to activated carbon in order to determine their ability to adsorb the same dye. Was performed to study the kinetics of reaction through the pseudo-first model and pseudo-second order where all samples followed the type of pseudo-second order. The results were very promising, with the red mud activated by calcium nitrate at 500ºC showed a maximum adsorption capacity of 476.02 mg/g at pH 4. The results for the activated carbon did not indicate affinity between the adsorbate and adsorbate material, a factor... (Complete abstract click electronic access below) / Mestre
35

Treatments of hemi caustic and extractives streams

Gandi, Ravikishor 22 May 2012 (has links)
Disposal of effluent from pulp and paper industry is one of the major problems faced by entrepreneur in view of increasing environmental standards day by day. In addition to this, industry loses economic value by disposing the effluent or selling it for a low price to other industries. Therefore, to address this problem, in the present study, 2 pulp mill effluents were selected to recover the economic value namely Hemi caustic stream and brown stock filtrate. As far as the recovery of value of hemi caustic stream is concerned, freeze concentration technique was used to recover water in its pure form and membrane separation was used to separate hemi cellulose from effluent so that permeate can be used as a pure source of caustic elsewhere. In addition to this, hemi caustic stream was subjected to acid hydrolysis to convert hemi cellulose into sugars. These sugars can be used to produce bioethanol. As far as the recovery of values of brown stock filtrate is concerned, it was proposed to recycle brown stock filtrate as a source of washing water for brown stock washers in the mill. However, continuous recycling of brown stock filtrate into the process causes building up of extractives in the recycle stream which in turn might deposit on the pulp and affects the quality of the pulp. Therefore, it was decided to separate extractives from the brown stock filtrate before recycle it into the mill. Dissolved Air flotation technique was used to achieve the above mentioned objective. An attempt was made to develop an improved and most reliable version of existing extractives measurement method to quantify the performance of Dissolved air flotation technique.
36

Temperature and infiltration characterization of a constructed wetland for wastewater treatment /

Gregory, Christopher T. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 74-77). Also available on the World Wide Web.
37

The impact of a revised effluent colour standard on the operation of a textile mill in Hammarsdale : a business case study.

Strassburg, Peter John. January 2004 (has links)
At present, raw aqueous textile effluent produced by textile mills in Hammarsdale, KwaZulu- Natal is reticulated voluntarily to the Hammarsdale Wastewater Works owned by the eThekwini Municipality and operated by Ethekwini Water and Sanitation. Thereafter the treated effluent is discharged into the Sterkspruit River which flows into the Shongweni impoundment. The cost to these textile mills of treating this effluent is calculated using a trade tariff formula administered by Ethekwini Water and Sanitation. In principle this arrangement is governed as follows; • in the case of the textile mills, by Sewage Disposal Bylaws set by Ethekwini Water and Sanitation, and • in the case of Ethekwini Water and Sanitation by a licence issued by the Department of Water Affairs and Forestry in terms of the National Water Act 36 of 1998. This Act prescribes a General Effluent Standard which specifies the quantity, quality and temperature of treated effluent which may enter a defined water resource such as the Sterkspruit River. In practice however, the Hammarsdale Wastewater Works is not licensed by the Department of Water Affairs and Forestry and operates temporarily according to an Exemption Permit issued to Umgeni Water who owned and operated the Hammarsdale Wastewater Works until 2003. It is thus incumbent upon Ethekwini Water and Sanitation to obtain a licence from the Department of Water Affairs and Forestry in order to comply with the requirements of the National Water Act and be allowed to operate the Hammarsdale Wastewater Works on a permanent basis. However, because of design limitations, the Hammarsdale Wastewater Works cannot remove the visible colour continuously and reliably from incoming raw textile effluent. The consequence of this is that the Sterkspruit River is often contaminated by coloured discharges from the Hammarsdale Wastewater Works. In terms of the National Water Act this situation is illegal and must be remedied. The approach adopted by Ethekwini Water and Sanitation has been to amend the Sewage Disposal Bylaws to oblige the textile mills (by the use of permits), by certain dates, to remove all, or most of the colour (to specified levels according to the test method used) from their effluent before it will be admitted to the Hammarsdale Wastewater Works for disposal. The costs of compliance will have to be borne by the individual textile mills. This business case study explores the impact of this obligation on the business of Textile Mill A and examines solutions to the problem. After a review of the efforts of that company to conform with the concept of Cleaner Production, it was decided to perform an end-of-pipe effluent treatment trial using a skid mounted pilot-plant utilising an adsorption and flocculation mechanism followed by cold soda ash softening, 'polishing' through a column of granular activated carbon and the removal of calcium and magnesium through a cation exchange softening column. The results obtained were; • that the permit requirements of Ethekwini Water and Sanitation could be met, • that a financial 'break-even' point could be achieved at the start of the project in 2005 should 43% of the treated effluent be recovered for reuse, • that a realistic rate of water recovery would be 50% resulting in a positive contribution in present day terms (2004) of R65 000 in 2005 increasing to Rl 377 000 in 2014, • that this rate of recovery could be increased should a demineraliser be introduced into the treatment train, and • that the project could be financed by a vendor on a Build, Own, Operate and Transfer basis with transfer of ownership to Textile Mill A occurring after 5 years. The results of that trial showed that end-of-pipe effluent treatment is a viable option, technically and commercially, for Textile Mill A considering the current inclement trading conditions being experienced by the South African textile industry. It is also a means of assisting Ethekwini Water and Sanitation to comply with the requirements of the National Water Act. / Thesis (M.B.A.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.
38

Assessing the Source of Fecal Contamination in Streams on Kaua'i Based on Concentration and Genotypes of FRNA Bacteriophages

Vithanage, Gayatri 08 1900 (has links)
Extensive data from O'ahu indicate that all streams on this island consistently exceed the USEPA standards (200 fecal coliform/100 ml, 33 enterococci/100 ml) for water quality. Soil was determined to be the source of the elevated counts of these bacteria. In tropical areas, as Hawai'i, these bacteria are able to survive and multiply in the soil. Thus, these bacteria can end up in nearby streams after heavy rains or due to erosion. As a result, the USEPA recommended indicator bacteria (fecal coliform, enterococci) cannot be used to reliably determine when waters in tropical areas are fecally contaminated. Several alternative indicators have been proposed for such areas such as C. perfringens and FRNA coliphages. Extensive monitoring data does not exist for the other islands of Hawai'i. Kaua'i differs from O'ahu in that it is older, wetter and contains an abundance of cesspools. The Nawiliwili Watershed, on the island of Kaua'i, was chosen for this study. Sampling was conducted over a period of one year, and all samples were assayed for the traditional USEPA indicators (fecal, coliform, enterococci) as well as two alternative indicators (C. perfringens, FRNA coliphages). Of the 14 sites sampled, 12 contained levels of fecal coliform and enterococci that exceeded the USEPA standards (200 fecal coliform/100 ml and 33 enterococci/100 ml. This is similar to what has been documented in O'ahu streams. Based on the concentrations of these indicator bacteria, the USEPA would deem these sites as sewage contaminated. However, monitoring of these same sites for C. perfringens indicated that there was no sewage contamination (geometric mean values fell below the proposed standard of 50 CFU/100 ml). FRNA coliphage data indicate that cesspools may be leaching into nearby streams. Two streams (Nawiliwili, Papakōlea) had geometric mean levels greater than the 50 PFU/100 ml (based on O'ahu streams). Other streams in the watershed may be sporadically contaminated by cesspool because elevated FRNA coliphage levels were detected on occasion. Genotyping these FRNA coliphage isolates furthered supported the theory that cesspools were contaminating these sites because 98% of the FRNA isolates were typed as human while only 2% were typed as of animal origin. Current USEPA standards (fecal coliform, enterococci) are not reliable indicators of sewage pollution in tropical areas, thus, alternative indicators such as C. perfringens and FRNA coliphages may prove to be better indicators in these areas.
39

Evaluation of the incidence of enteric viruses, Vibrio species and Escherichia coli pathotypes in effluents of two wastewater treatment plants located in Keiskammahoek and Stutterheim in the Eastern Cape Province of South Africa

Adefisoye, Martins Ajibade January 2016 (has links)
South Africa is currently experiencing water shortage crisis, a challenge that has been attributed not only to the scarcity of freshwater, but also to fast degrading water quality. Factors such as rapid urbanisation, population and economic growth, climate change as well as poor operational and maintenance of many of the exisiting water/wastewater treatment facilities have been acknowledged as important contributors to degrading water quality in the country. Untreated or inadequately treated discharged wastewater effluents constitute point source pollution to many freshwater environments in South Africa. Hence, it becomes imperative to evaluate wastewater discharges in other to protect the scarce freshwater resource, the environment and public health. Over a twelve-month sampling period (September 2012 to August 2013), we assessed the bacteriological, virological and physicochemical qualities of the discharged final effluents of two wastewater treatment facilities in the Eastern Cape Province of South Africa. For the physicochemical assessment, a total of 144 final effluent samples were collected from both the final effluent tanks (FE) and the discharge points (DP) of the treatment facilities. Physicochemical parameters including pH, temperature, turbidity, total dissolved solids (TDS), dissolved oxygen (DO), electrical conductivity (EC) and free chlorine concentration were determined on site while biological oxygen demand (BOD), nitrate (NO3-), nitrite (NO2-), phosphate (PO4-) and chemical oxygen demand (COD) were determined in the laboratory. The bacteriological analysis of the samples was done using standard membrane filtration (MF) technique. Bacterial group assessed included: faecal indicator bacteria (faecal coliforms and E. coli) and Vibrio species, while the antibiotic susceptibility profiles of selected E. coli and Vibrio species isolates against some selected antibiotics commonly used in human therapy and veterinary medicine were determind using the standard agar-disc diffusion method. The occurrence and concentrations of human enteric viruses including: human adenovirus (HAdV), hepatitis A virus (HAV) and rotavirus (RoV) in the samples were determined by TaqMan-based real-time polymerase chain reaction (qPCR) following concentration by adsorption-elution method. The physicochemical characteristics of the samples ranged as follows: pH (6.5 – 7.6), TDS (95 – 171 mg/L), EC (134 – 267 μS/cm), temperature (12 – 27 °C), turbidity (1.5 – 65.7 mg/L), free chlorine (0.08 – 0.72 mg/L), DO (2.06 – 9.81 mg/L), BOD (0.13 – 9.81 mg/L), NO3- (0 – 21.5 mg/L), NO2- (0 – 0.72 mg/L), PO4- (0 – 18.3 mg/L) and COD (27 – 680 mg/L). Some of the characteristic such as pH, TDS, EC, temperature, nitrite and DO (on most instances) complied with recommended guidelines. Other characteristics, however, including turbidity, BOD, nitrate, phosphate and COD fell short of the recommended guidelines. All the 48 samples analysed for bacteriological qualities tested positive for the presence of the bacterial groups with significant (P≤0.05) seasonal variation in their densities. Faecal coliforms were detected in counts ranging from 1 CFU/100ml to 2.7 × 104 CFU/100ml. Presumptive E. coli counts ranged generally between 1 CFU/100ml – 1.4 × 105 CFU/100ml while counts of presumptive Vibrio species ranged between 4 CFU/100ml – 1.4 × 104 CFU/100ml. Molecular identification of the presumptive isolates by polymerase chain reactions PCR gave positive reaction rates of 76.2 percent (381/500) and 69.8 percent (279/400) for E.coli and Vibrio species respectively. The antibiotic susceptibility profiling of 205 PCR-confirmed Vibiro isolates against 18 commomly used antibiotics showed resistance frequencies ranging from 0.5 percent (imipenem) to 96.1 percent (penicillin G) at recommended breakpoint concentrations. Eighty-one percent (166/205) of the Vibrio isolates showed multidrug resistance (resistance to 3 or more antibiotics) with the most common multiple antibiotic resistance phenotype (MARP) being AP-T-TM-SMX-PG-NI-PB, occurring in 8 isolates.
40

Uniformidade de irrigação por gotejamento usando efluente tratado de abatedouro de aves / Uniformity in drip irrigation for treated wastewater application from poultry slaughterhouse

Morais, James 07 July 2018 (has links)
Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2018-02-05T18:26:08Z No. of bitstreams: 2 James_ Morais2018.pdf: 2489413 bytes, checksum: 8a6f574d868e585f5e6e2fef836e47fb (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-05T18:26:08Z (GMT). No. of bitstreams: 2 James_ Morais2018.pdf: 2489413 bytes, checksum: 8a6f574d868e585f5e6e2fef836e47fb (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-07-07 / The processes that take part of poultry slaughter are responsible for a great amount of water consumption and, consequently, a generation of large volumes of wastewater, which are usually disposed on soil without any control of uniformity regarding its distribution. Thus, this study aimed at evaluating a drip irrigation system, applied to dispose treated poultry slaughterhouse effluent on soil, using three effluent application rates of 100, 200 and 300 m³ ha-1 day-1. Besides the irrigation system, the effluent quality was also evaluated according to its physical-chemical characteristics. The evaluation of the results was given by the following coefficients: Christiansen Uniformity (CUC), Uniform Distribution (UDC), the Statistical Uniformity Coefficient (SUC) as well as quality control techniques. This trial was carried out in an eucalyptus reforestation area from the Industrial Poultry Slaughterhouse of Lar Agroindustrial Cooperative, in Matelândia city, PR. According to data obtained in this research, it was concluded that drip irrigation system, using the proposed rates, can be considered adequate, since it has shown uniformity in distribution of flows, pH and electrical conductivity. For pH and electrical conductivity, all the evaluated uniformity coefficients, CUC, UDC and SUC, were estimated in more than 90% and considered excellent. For the flow rates, all the coefficients were estimated as superior to 90% for 100 m³ ha-1 day-1 treatment and above 80% for treatments of 200 and 300 m³ ha-1 day-1. Usually, the distributions showed the highest coefficient of uniformity for the three parameters evaluated in the three studied treatments, for the highest tested rate of application. Regarding the effluent characterization, it was concluded that its main characteristics are the concentrations of nitrogen, phosphorus and carbon. And during the experiment, the industry kept the standards of disposal in the environment, which were determined by the environmental agencies. Finally, it was concluded that the statistical process control is adequate to evaluate the effluents as well as irrigation uniformity in tests area. / Os processos inerentes ao abate de aves respondem por um grande consumo de água e, consequentemente, a geração de grandes volumes de efluentes que, em geral, são dispostos no solo sem qualquer controle de uniformidade sobre a distribuição. Assim, o objetivo deste estudo foi avaliar um sistema de irrigação por gotejamento, aplicado à disposição de efluente tratado de abatedouro de aves no solo, utilizando três taxas de aplicação de efluente: 100, 200 e 300 m³ ha-1 dia-1. Além do sistema de irrigação, a qualidade do efluente também foi avaliada em função das características físico-químicas. A avaliação dos resultados foi dada pelos Coeficientes de Uniformidade de Christiansen (CUC), de Uniformidade de Distribuição (CUD), de Uniformidade Estatístico (CUE), bem como pelas técnicas de controle de qualidade. O experimento foi realizado na área de reflorestamento com eucalipto da Unidade Industrial de Aves da Lar Cooperativa Agroindustrial, em Matelândia, PR. De acordo com os dados obtidos neste trabalho, concluiu-se que o sistema de irrigação por gotejamento, utilizando-se as taxas propostas, pode ser considerado apropriado, pois apresentou uniformidade na distribuição das vazões, do pH e da condutividade elétrica. Para o pH e a condutividade elétrica, todos os coeficientes de uniformidade avaliados, CUC, CUD e CUE, foram estimados em mais de 90%, considerados excelentes. Para as vazões, todos os coeficientes foram estimados acima dos 90% para o tratamento de 100 m³ ha-1 dia-1 e acima dos 80% para os tratamentos de 200 e 300 m³ ha-1 dia-1. Em geral, as distribuições apresentaram maior coeficiente de uniformidade, para os três parâmetros avaliados, nos três tratamentos, para a maior taxa de aplicação testada. Em relação à caracterização do efluente, concluiu-se que suas principais características são as concentrações de nitrogênio, fósforo e carbono. E, durante o experimento, a indústria manteve os padrões de lançamento no ambiente, determinados pelos órgãos ambientais. Por fim, concluiu-se que o controle estatístico de processo é adequado à avaliação, tanto de efluentes quanto de uniformidade na irrigação, em testes a campo.

Page generated in 0.4839 seconds