Spelling suggestions: "subject:"sanitary"" "subject:"anitary""
731 |
Removal Of Lead Using Anaerobic BiomassTokcaer, Emre 01 September 2003 (has links) (PDF)
Use of anaerobically digested sludge (ADS) in heavy metal removal, was researched. The raw and dewatered ADS samples collected from the effluent of anaerobic digesters and mechanical dewatering units of Ankara City Wastewater Treatment Plant were used. Sorption kinetic and equilibrium tests were conducted using raw ADS at initial pH of 2.0, 4.0 and without adjusting the initial pH. The highest Pb(II) removal capacity was observed as, 8.5 mmol (or 1760 mg) Pb(II) per g of biomass, when the initial pH was not controlled. When dewatered ADS was used Pb(II) removal capacity of ADS was found to drastically decrease to 2.5 mmol (or 518 mg) Pb(II) per g of biomass.
Both biomass samples resulted in an increase in the solution pH from an initial value of 4 &ndash / 5 to an equilibrium value of 7 &ndash / 8. Large floc particles settling rapidly were formed after the ADS samples contacted with Pb(II) solution. The high Pb(II) removal capacities, and visual observations during the experiments indicated that precipitation is a dominant mechanism especially at low initial Pb(II) concentrations.
FTIR studies showed that carboxyl groups present in the biomass surface of raw ADS were major functional groups in biosorption of Pb(II). The low capacity values attained at initial pH 2.0 indicated that there was a competition between Pb(II) species and hydrogen ions for carboxyl groups.
Single and 3-stage fed-batch reactor systems were operated using raw ADS at different initial Pb(II) concentrations. The efficiency of reactor systems increased when 3-stage fed-batch configuration was used and an effluent Pb(II) concentration below 2 mg/L was reached from an initial value of about 200 mg/L.
|
732 |
Treatment Of Xenobiotics During Anaerobic Digestion And Its Enhancement Upon Post-ozonation Of The Anaerobically Treated SludgeAk, Munire Selcen 01 November 2012 (has links) (PDF)
Treatment of waste sludge has become an important issue in recent years around the world. However, the trend of waste sludge treatment has shifted from volume minimization and stabilization to reuse of the sludge and recover the energy potential of it. Therefore, anaerobic treatment of sludge is gaining popularity because of byproduct methane production and high percentage of VSS reduction. Pre-treatment of sludge before anaerobic digestion in order to increase methane production, and ozone pre-treatment in this context, is one such option. Domestic sludge also contains the recently recognized, so called, emerging compounds such as Endocrine Disrupting Compounds (EDCs). Therefore treatment of EDCs in sludge is another challenge in waste sludge treatment since direct discharge of such chemicals may harm the environment by causing gender shifts within the fauna. In this context two hormones (estrone and progesterone), three pharmaceuticals (acetaminophen, carbamazepine and diltiazem) and one plasticizer (benzyl-butyl phthalate) were routinely analyzed in sludge samples which were subjected to treatment during this study. Treatment of EDCs during anaerobic digestion and the effect of ozonation both on the performance of digestion and the treatability of EDCs were investigated in this study.
Four 2.5L anaerobic jars were used for anaerobic digestion connected to four 1L plastic graduated cylinders immersed in salt-water to collect the off gas. Anaerobic sludge culture of the reactor and the sludge feed to the reactors were obtained from Ankara Tatlar Wastewater Treatment Plant anaerobic digester and return activated sludge (RAS) line, respectively. One of the anaerobic digesters was used as control (no ozonation) and the others were fed with sludge samples ozonated at three different ozone doses 0.65, 1.33 and 2.65 mg ozone/g biomass. Sludge ages of the reactors were initially set to 25 days and the reactors were fed once every 2 days. The TSS, VSS, total gas volume, COD, pH, CH4 percentage and EDCs were analyzed routinely. In the reactors, operated at 25 days, because of the observation of reduction of TSS, SRT was set to infinity / thus, sludge wastage was terminated.
Following the startup it was seen that at 2.65 mg ozone/g biomass dose TSS and VSS did not stay constant in the reactor and dropped sharply in the course of operation, indicating that system was not steady at this SRT. However, upon stoppage of sludge wastage from the reactors, thereby setting SRT to infinity, a steady culture could be maintained in the reactors. Both total gas production and CH4 percentage increased with the increasing doses of ozone with respect to control reactor. For 2.65 mg/g ozonated reactor total gas volume doubled the amount produced in the control reactor.
All the EDCs within the scope of this study were analyzed in sludge using ultrasound-aided sequential sludge extraction method twice a week and the results showed that ozonation affected treatment of EDCs for up to 96%. The highest removal rate was obtained with natural hormones. Rates of treatment of pharmaceuticals were the second best.
|
733 |
Model simulation of contaminant movement from a sanitary landfillHineline, T. Lawrence 03 June 2011 (has links)
The potential for leachate movement out of a sanitary landfill was evaluated and simulated by a computer program model. Landfill operations and geohydrological conditions in the area were investigated in order to develop a conceptual model of the system and to obtain numerical data for the development of the simulation.The landfill is operated in a 20 to 27 foot thick clay till which overlies a 10 foot thick, continuous sand and gravel aquifer. Monitor wells located around the site indicate minimal changes in groundwater quality to this date. This is attributed to the slow movement of leachate through the confining layer which would take at least 5 to 10 years.Numerical parameters not readily determined were varied in 16 simulations. This procedure allowed analysis of the different plumes developed as well as observation of the program’s sensitivity to such changes. In simulations of five years from the time leachate would enter the aquifer, leachate plumes were developed which extended a mile and one half down the hydrologic gradient from the landfill. Varying the parameters led to fairly consistant conclusions regarding the effects of the landfill.Ball State UniversityMuncie, IN 47306
|
734 |
Performance Assessment Of Compacted Bentonite/sand Mixtures Utilized As Isolation Material In Underground Waste Disposal RepositoriesAda, Mahir 01 July 2007 (has links) (PDF)
The design and development of isolation or backfill materials, which seal the disposal facility, are important for disposing the wastes. The use of compacted bentonite-sand for construction of shaft seals and liners for waste containment structures has been proposed by various studies. Therefore / it is aimed in this study to develop an isolation material to be used in underground waste repositories. For such designs to be effective, their performance need to be assessed and a minimum hydraulic conductivity requirement defined by regulatory agencies should be satisfied (i.e. 1x10-8 m/s in Turkey, 1x10-9 m/s in USA). Therefore / this study assesses the performance of compacted bentonite/sand mixtures in terms of hydrological and mechanical properties. To be able to assess the performance of this material, a variety of laboratory tests were carried out. Engineering geological tests such as compaction, falling head permeability, swelling, unconfined compression and shear strength tests were conducted to select an optimum mixture. Finally, an optimum bentonite-sand mixture possessing 30% bentonite was recommended for the isolation of underground waste disposal facilities.
|
735 |
Municipal Sludge Minimization: Evaluation Of Ultrasonic And Acidic Pretreatment Methods And Their Subsequent Effects On Anaerobic DigestionApul, Onur Guven 01 February 2009 (has links) (PDF)
Sludge management is one of the most difficult and expensive problems in
wastewater treatment plant operation. Consequently, & / #8216 / sludge minimization& / #8217 / concept
arose to solve the excess sludge production by sludge pretreatment.
Sludge pretreatment converts the waste sludge into a more bioavailable substrate
for anaerobic digestion and leads to an enhanced degradation. The enhanced degradation
results in more organic reduction and more biogas production. Therefore, sludge
pretreatment is a means of improving sludge management in a treatment plant.
Among pretreatment methods, acidic pretreatment has been subject of limited
successful studies reported in the literature. On the contrary / ultrasonic pretreatment was
reported as an effective pretreatment method. Main objective of this study was to investigate the effects of these two pretreatment methods and their combination in order
to achieve a synergistic effect and improve the success of both pretreatment methods.
Experimental investigation of pretreatment methods consists of preliminary
studies for deciding the most appropriate pretreatment method. Anaerobic batch tests
were conducted for optimization of the parameters of selected method. Finally, operation
of semi-continuous anaerobic reactors was to investigate the effect of pretreatment on
anaerobic digestion in details.
Preliminary studies indicated that, more effective pretreatment method in terms
of solubilization of organics is ultrasonic pretreatment. Fifteen minutes of sonication
enhanced 50 mg/L initial soluble COD concentration up to a value of 2500 mg/L.
Biochemical methane potential tests indicated that the increased soluble substrate
improved anaerobic biodegradability concurrently. Finally, semi-continuous anaerobic
reactors were used to investigate the efficiency of pretreatment under different operating
conditions.
Results indicate that at SRT 15 days and OLR 0.5 kg/m3d ultrasonic pretreatment
improved the daily biogas production of anaerobic digester by 49% and methane
percentage by 16% and 24% more volatile solids were removed after pretreatment.
Moreover, even after pushing reactors into worse operating conditions such as shorter
solids retention time (7.5 days) and low strength influent, pretreatment worked
efficiently and improved the anaerobic digestion.
Finally cost calculations were performed. Considering the gatherings from
enhancement of biogas amount, higher methane percentage and smaller amounts of
volatile solid disposal from a treatment plant / installation and operation costs of
ultrasound were calculated. The payback period of the installation was found to be 4.7
years.
|
736 |
A Study On Modern Bathroom Through Sanitary Ware After The Nineteenth CenturyBaran, Gulsum 01 May 2010 (has links) (PDF)
In this study the design of the sanitary ware and bathrooms are examined, concentrating on small bathrooms and changing design aspects of bathrooms. The design considerations of bathrooms and the design of the bath tub, wash basin and toilet which forms the sanitary ware sets in bathrooms is reviewed as for being dominant elements of bathroom design.
|
737 |
The Role Of Calcium Ion On Activated Sludge Biochemical And Physical Properties In Phosphorus Deficient Growth MediumAksu, Ceren 01 September 2010 (has links) (PDF)
Nutrients and cations have significant effect on activated sludge characteristics and therefore effect the efficiency of whole processes. To determine the properties in phosphorus deficient medium and the effect of calcium ions two reactor sets with two different phosphorus concentration (C/N/P=100/5/0.05 and C/N/P=100/5/1), three different concentrations of calcium (0.5, 5, 15 meq/L) were operated with 8 days of sludge residence time and an effective volume of 2 L. Results showed amount and composition of EPS was dependent on calcium and phosphorus concentrations. Except for the highest calcium concentration, increase in phosphorus concentration resulted in increase in total EPS production. Under phosphorus deficient conditions, calcium ions stimulated the production of carbohydrate type polymers and viscous bulking was observed. However, the increase in phosphorus concentration led to increase in protein type polymer production and bulking condition was cured. Addition of calcium ions increased conductivity in both cases, but increase in phosphorus concentration caused decrease in conductivity. Increase in phosphorus concentration had improved settleability, dewaterability and rheology of sludge. Moreover, effluent turbidity was decreased and COD removal efficiency was recorded as greater than 95 % for all calcium concentrations under phosphorus sufficient conditions. Microscopic analyses showed that under phosphorus deficient conditions flocs were weak, dispersed and nonresistant. Increase in phosphorus concentration resulted in improvement of floc structure. Same Enterobacter and Citrobacter species were identified at all calcium concentrations under phosphorus deficient conditions. Yet, under phosphorus sufficient conditions different species were identified in control reactor as compared to 5 meq/L and 15 meq/L concentrations.
|
738 |
Sulphate Removal By Nanofiltration From WaterKarabacak, Asli 01 December 2010 (has links) (PDF)
ABSTRACT
SULPHATE REMOVAL BY NANOFILTRATION FROM WATER
Karabacak, Asli
M.Sc., Department of Environmental Engineering
Supervisor: Prof. Dr. Ü / lkü / Yetis
Co-advisor: Prof. Dr. Mehmet Kitis
December 2010, 152 pages
Excess sulphate in drinking water poses a problem due to adverse effects on human health and also due to aesthetic reasons. This study examines the nanofiltration (NF) of sulphate in surface water using a laboratory cross-flow device in total recycle mode. In the study, three NF membranes, namely DK-NF, DL-NF and NF-270, are used. The influence of the main operating conditions (transmembrane pressure, tangential velocity and membrane type) on the steady-state permeates fluxes and the retention of sulphate are evaluated. Kizilirmak River water is used as the raw water sample. During the experimental studies, the performance of NF is assessed in terms of the parameters of UVA254, sulphate, TOC and conductivity of the feed and permeates waters. Results indicated that NF could reduce sulphate levels in the surface water to a level below the guideline values, with a removal efficiency of around 98% with all three membranes. DK-NF and NF-270 membranes showed fouling when the surface water was fed directly to the system without any pre-treatment. MF was found to be an effective pretreatment option for the prevention of the membrane fouling, but no further removal of sulphate was achieved. Parametric study was also conducted. No change in flux values and in the removal of sulphate was observed when the crossflow velocity was lowered. The flux values were decreased as the transmembrane pressure was lowered / however there were not any decrease in the sulphate removal efficiency.
|
739 |
Production Of Alginate From Azotobacter Vinelandii And Its Use In Water And Wastewater TreatmentMoral, Cigdem 01 January 2011 (has links) (PDF)
Alginates are copolymers of &beta / -D-mannuronic (M) and &alpha / -L-guluronic acids (G). In this study, Azotobacter vinelandii ATCC® / 9046 was used to produce alginate in a fermentor. The effect of parameters such as dissolved oxygen tension (DOT), agitation speed, initial concentrations of sucrose and calcium
on the properties of alginate were examined. Changes of DOT in the range of 1 and 10 % affected alginate production. The optimum DOT giving high alginate yield (4.51 g/L) and maximum viscosity was observed as 5 % yielding moderate GG-blocks of 55 %. Both high and low agitation levels reduced alginate production, but these conditions increased GG-block alginates as 76 and 87 % at 200 and 700 rpm, respectively. Moderate
sucrose and calcium concentrations, 20 g/L and 50 mg/L, respectively were found better since further increase in their concentrations did not lead to a considerable improvement in alginate production and quality. Sodium alginates produced in this work were investigated for maximum heavy metal uptake with a special focus on copper ion and the highest copper uptake was around 1.9 mM Cu2+/g alginate. Findings showed that the block distribution of alginate was not as important as expected for copper removal. Alginate together with calcium ions was used for the removal of turbidity. The amount of GG-block was found to be important in turbidity removal. Alginate having 55 % GG block and 8.9 cP viscosity resulted in a final turbidity lower than 1 NTU at 2 mg/L of alginate with 60 mg/L of calcium ion.
|
740 |
Removal Of Endocrine Disrupter Compounds And Trace Organics In Membrane BioreactorsKomesli, Okan Tarik 01 July 2012 (has links) (PDF)
Endocrine disrupters and trace organic contaminants are recently recognized contaminants in wastewaters. Current concept is the multibarier approach where the contaminants are removed from the water cycle both by water and wastewater treatment facilities, as well as natural die-away. In this thesis work LC/MS/MS determination of selected EDC compounds, namely, diltiazem, progesterone, estrone, carbamazepine, benzyl butyl phthalate and acetaminophen, at ultra trace levels, have been carried out by optimizing analytical parameters. In addition, new methods were developed for their analysis in sludge samples at sub ppb levels. Following optimization and method development, occurrence of these contaminants in wastewaters and their removal in two full-scale and two pilot-scale membrane biological reactors (MBRs) was studied. Progesterone, estrone and acetaminophen were completely removed from wastewater by biodegradation. CBZ and diltiazem were not removed at all during the study. There was little effect of flux and sludge retention times on the removal of selected EDCs in these membrane plants. In SBR combined with membrane filtration, 13 different micropollutants, including Fluoxetine (FLX), Ibuprofen (IBP), Naproxen (NPX), Diclofenac (DCF), Carbamazepine (CBZ), Trimethoprim (TMP), Roxithromycin (ROX), Erythromycin (ERY), Sulfamethoxazole (SMX), Diazepam (DZP), Galaxolide (GLX), Tonalide (TON), Celestolide (CEL). CEL, GLX, TON and FLX were removed by adsorption onto the sludge while ROX, ERY, SMX, IBP and NPX were removed by biological degradation. The CBZ, DZP, TMP and DCF were not removed by biodegradation or adsorption. Whereas, following the addition of powdered activated carbon, all these compounds were removed entirely from the wastewater stream by accumulating in sludge.
|
Page generated in 0.0363 seconds