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The disposal of anaerobically digested sewage sludge onto farmland in Pima county has created the need to evaluate the potential public health impact of pathogens which are indigenous to sewage and may be present in sludge. The occurrence of enteroviruses and Giardia cysts in sewage sludge before and after anaerobic digestion was monitored for a period of 14 months. This study showed that significant concentrations of enteroviruses and Giardia cysts are present in anaerobically digested sewage sludge being applied to farmland in Pima County. The concentration of Giardia cysts ranged from 1.33 x 103 to 8.6 x 104 per liter of raw sludge and 2.0 x 103 to 2.8 x 104 per liter of treated sludge. The concentration of enteroviruses in sludge ranged from 1.74 x 102 to 1.28 x 104 per liter before anaerobic digestion and from <2 to 5.63 x 10 2 per liter after treatment. The percentage of virus removal after anaerobic sludge digestion varied from 73% to >99.95%. Methods to study the fate of enteroviruses in the sludge-soil matrix were also evaluated. An increase in the ratio of eluant to solids seemed to enhance virus recoveries from sludge:soil mixtures.

Pentachlorophenol (PCP) is a biocide which is widely used for its toxicity to microorganisms. Its major application is in wood preservation, and PCP at abandoned wood preserving sites is a major source of environmental pollution. Although much of the literature documents aerobic treatment for PCP, research indicates that there is great potential for anaerobic dechlorination of these compounds. The objectives of this investigation were to study the acidogenesis phase of the anaerobic biodegradation process; how acidogenesis is affected by PCP toxicity alone and in the presence of zinc; what role acidogenesis plays in the biodegradation of PCP; and how operating parameters, such as organic loading rate (OLR) and solids retention time (SRT) affect the degradation of PCP during acidogenesis. Batch anaerobic toxicity assays (ATAs) were performed to quantify the toxicity threshold for PCP and zinc, and to study the effect of these toxicants on volatile acids production. Continuous reactors (chemostats) were operated at SRTs of 0.25-0.61 day to kinetically exclude methanogenesis from acetate, so that the effects of the toxicants on acidogenesis could be evaluated PCP was found to have a toxicity threshold of 2.7-3.0 mg/L and zinc 23-27 mg/L in batch systems. Acetate utilizers showed the first signs of inhibition in PCP spiked systems, whereas hydrogen utilizers were the first organisms affected in response to a zinc spike. In the continuous systems, PCP in spike concentrations of 7.0 mg/L did not affect the quantity or composition of volatile acids produced in the chemostats. A rise in headspace hydrogen at 30 mg/L zinc indicated that hydrogen utilizers became inhibited in the presence of high zinc concentrations PCP was degraded, with approximately half of the degradation occurring during acidogenesis. GC/MS analysis detected no intermediate chlorophenols in the effluent. The efficiency of degradation varied indirectly with spike concentration and directly with SRT / acase@tulane.edu

Anaerobic biological waste treatment is a complex microbiological process involving many types of bacteria. The anaerobic conversion of organic matter occurs in three steps, the last step being the conversion of volatile acids, mainly acetate, to gaseous end products. In the anaerobic treatment of wastewater containing sulfates, sulfate reducing bacteria (SRB) and methane producing bacteria (MPB) affect the last step. Since acetate is a common substrate for both SRB and MPB, there exists competition between them for available acetate. The outcome of the competition between SRB and MPB for acetate has a significant influence on effluent quality, treatment efficiency, and quality and quantity of biogas produced. The major objectives of this research were to study the effects of COD/SO$\sb4$ ratio and redox potential on the interaction between SRB and MPB and to study the relative effectiveness of SRB and MPB in degrading selected phenolic compounds Batch serum bottle studies were conducted to verify if sulfate utilization by SRB followed stoichiometric sulfate utilization and to determine Monod kinetic parameters for acetate uptake. Results indicated that sulfate reduction followed closely the stoichiometric sulfate reduction (COD/SO$\sb4$:0.62/1). Monod kinetic constants, K$\sb{\rm s}$ and k were found to be 103 mg acetate/L and 2.52/d, respectively, for SRB, 133 mg acetate/L and 3.24/d, respectively, for MPB, and 196 mg acetate/L and 4.30/d, respectively, for mixed culture of SRB and MPB The effect of COD/SO$\sb4$ ratio on the interaction between SRB and MPB was studied in batch (serum bottle) and continuous (chemostat) systems. Chemostats were run at a solids retention time (SRT) of 10 days. Results from both batch and continuous systems indicated that as the COD/SO$\sb4$ ratio decreased, the percent acetate utilized by SRB increased The effect of redox potential on the interaction between SRB and MPB was studied in the Eh ranges of $-$50 to $-$100, $-$150 to $-$200, and $-$250 to $-$300 mV. Results indicated that as the redox potential increased, the percent acetate utilized by SRB increased Biodegradation of 2,4,6-trichlorophenol (2,4,6-TCP) was studied with enrichments of SRB, MPB and mixed cultures. The concentrations of 2,4,6-TCP studied were 15, 30, and 45 mg/L. Results from this experiment indicated that SRB enrichment was more effective than MPB and mixed cultures in removing 2,4,6-TCP Biodegradation of 2-chlorophenol (2-CP), 2,3-dichlorophenol (2,3-DCP), 2,5-dichlorophenol (2,5-DCP) and 2,3,5-trichlorophenol (2,3,5-TCP) was studied at concentrations of 2.5, 5, and 10 mg/l of each of the toxicants using enrichments of SRB, MPB and mixed cultures. All these cultures were found to remove all the chlorophenols studied with very high efficiency (between 70 to 100%). 2,3,5-TCP was found to be reductively dehalogenated to end products via 3,5-dichlorophenol and 3-chlorophenol, while, 2,3-DCP and 2,5-DCP were dehalogenated via 2-CP. 2-nitrophenol, 4-nitrophenol, and 2,4-dinitrophenol were also found to be removed at concentrations of 5, 10 and 15 mg/L each, by enrichments of SRB, MPB and mixed cultures. The removals ranged from 83 to 100%. 2,4-DNP was found to be transformed via 4-NP. The removals of chlorophenols and nitrophenols compare well with those reported in the literature / acase@tulane.edu

The fate and occurrence of Giardia and Cryptosporidium were studied in the marine environment to assess their potential for transmission since their transmission to swimmers in fresh waters has been previously documented. The first part of this study was designed to determine the occurrence of Giardia and Cryptosporidium at bathing beaches within the vicinity of an outfall discharging primary treated sewage into Mamala Bay, Hawaii. Sites were monitored monthly and quarterly for parasites by passing 400 liters of marine water through a spun polyproplyene fiber filter. Giardia and Cryptosporidium were detected in primary treated sewage from the Sand Island sewage treatment plant which discharges into Mamala Bay at concentrations of 2,560 cysts and 216 oocysts/liter, respectively. Ala Wai Canal as well as the bathing beaches within the vicinity of the outfall were also found to contain the parasites. The survival of Giardia in marine water was studied in direct sunlight and the dark in marine waters (33- to 35-ppt salinity), canal water (28-ppt salinity) and in phosphate-buffered saline (8-ppt) at 18 to 28°C. Giardia muris was inactivated by 3-logs in the presence of sunlight in marine and canal waters. In comparison, Giardia survive up to 6 hours in PBS under the same conditions. Overall, it appears that salinity and sunlight quickly inactivate Giardia cysts. Thus, Giardia would pose a threat only if the cysts reach the bathing beaches within a few hours. The last phase of this project was designed to develop a more efficient method of collection of cysts and oocysts from water. Methods for the concentration of enteric viruses, Giardia and Cryptosporidium from water requires the use of two different types of filters. This study compared the efficiency of their concentration from tap water and tertiary treated wastewater with a polypropylene fiber cartridge, and the Filterite electronegative and the 1MDS Virosorb electropositive microporous filters. Results indicated that the overall efficiency was greatest for the Filterite filter for both Giardia and Cryptosporidium (p = 0.000762 and p = 0.067069, respectively); and in addition they are easier and faster to process than the polypropylene-wound parasite filter.

L’aménagement des systèmes d’assainissement conventionnel des eaux usées domestiques entraine actuellement la déplétion de ressources naturelles et la pollution des milieux récepteurs. L’utilisation d’une approche écosystémique plus globale telle que l’Assainissement Écologique, visant la fermeture du cycle de l’eau et des éléments nutritifs (phosphore et azote), contenus dans les excréments, par leur réutilisation à travers l’agriculture, permettrait d’améliorer de façon écologique cette situation. Toutefois, ce paradigme émergent est peu enseigné aux professionnels de l’aménagement responsables de sa planification, surtout au niveau de son application dans les pays développés nordiques. C’est pourquoi, afin d’améliorer la planification de ce type de système, il faut informer ces derniers des pratiques les plus adéquates à adopter. Pour y arriver, un scénario d’aménagement type a été développé à partir d’une revue exhaustive de la littérature et de l’analyse des données en se basant sur les recommandations de l’approche en fonction du contexte étudié. Ce scénario aidera les professionnels à mieux comprendre l’Assainissement Écologique et son aménagement. Il représente alors un point de départ pour les discussions interdisciplinaires et participatives que celui-ci requiert. En conclusion, il y a encore de nombreux manques d’informations concernant l’utilisation de traitements alternatifs dans les climats nordiques et l’acceptation de ceux-ci par les usagers. De plus, les cadres législatifs demeurent un obstacle considérable à l’aménagement d’un tel système. Cette recherche permet cependant de démystifier l’approche auprès des professionnels et pourrait aider à modifier certains cadres législatifs afin d’y intégrer sa philosophie. / At the moment, the planning of conventional sanitation systems for the treatment of domestic wastewater is responsible for the depletion of natural resources and pollution of receiving waters. A more holistic approach, respecting the local ecosystem, such as the new paradigm of Ecological Sanitation would greatly improve this situation. The idea pursues the closure of water and nutrients (nitrogen and phosphorus found in the human excreta) cycles through their reuse in agriculture. However, this new approach remains relatively unknown except for a few planning professionals responsible for the implementation of sanitation systems especially in the context of northern industrialized countries. Therefore to enhance the design of this kind of system, there is a need to educate and inform these professionals on more suitable treatment options to adopt. To achieve this, a planning scenario has been developed using a literature review and analysis of the data using a grid based on the recommendations of the paradigm when planned in this particular context. This scenario will help the professionals to better understand the philosophy of this approach and its implementation. It will represent a starting point for the interdisciplinary and participatory discussions that this approach demands. In conclusion, there is still a lack of knowledge surrounding the use of certain alternative options and their degree of acceptance by the public. Moreover, the legislation surrounding sanitation represents a significant obstacle to the implementation of this sort of alternative system. Still, this research helps the planning and design professionals demystify the new paradigm and may even be helpful in the modification of laws for the integration of its philosophy.

Separation of dissolved metals from aqueous solutions using liquid membrane technology is highly advantageous owing to the degree of separation achieved, efficiency and application potential. In the present investigation four types of liquid membranes - bulk liquid membrane (BLM), emulsion liquid membrane (ELM), electrostatic pseudo liquid membrane (ESPLIM) and unified liquid membrane (ULM) have been extensively studied, for their application in extraction and concentration of dissolved metals from effluents. Experiments were conducted with various metal systems to optimize both system and process conditions and to find out the effect of various parameters on the performance of the process. Different mass transport models were proposed for each type, taking diffusional and kinetic resistances into account. Models were extended for simultaneous extraction systems and were verified by different metal-carrier experiments. Good agreement was found between the concentration profiles obtained from the models and the experimental data, thereby establishing the validity of models for all the four types of liquid membranes. The stirred cell employed in BLM process eliminates emulsification and demulsification processes. It also provides simultaneous contact of the organic liquid membrane phase with aqueous feed and strip phases. Overall rate expressions for extraction and stripping in BLM are based on an assumed kinetic mechanism to explain the process qualitatively. It was found that the magnitude^ of diffusional and kinetic resistances determines the overall mass transfer coefficient. The relative magnitude of mass transfer coefficient, reaction rate constants and equilibrium constants enables to visualize the controlling regime of the process. The problem of low flux rate due to high diffusion resistances, inefficient operation and exorbitant costs encountered in bulk and supported liquid membranes (SLM) are overcome in an ELM. In the ELM process, an emulsion of organic membrane phase and aqueous inner phase, is dispersed in the continuous aqueous feed phase. This gives a highly selective and ultra thin liquid film generating a large mass transfer area for separation. Experimental results on membrane instability and emulsion swelling indicate that volumetric leakage rate depends linearly on the stirring speed and that the nature of surfactant does not have any appreciable effect on emulsion swelling. A general permeation model was developed taking into account the external mass transfer around the emulsion drop, diffusion in the drop, reaction at the aqueous-organic interface, leakage of the internal phase to the external phase due to membrane breakup and emulsion swelling due to osmotic pressure difference. Model equations with appropriate boundary conditions were numerically solved by orthogonal collocation technique for a set of model parameters obtained either from known correlations or from independent experiments. Comparison of the model predictions with experimental data from the batch permeation of chromium and other metals using carrier Alamine 336 or LIX 64N, shows that the model predictions are in very good agreement with the experimental findings. Further this model can be used to simulate the effects of various experimental conditions such as metal and hydrogen ion concentrations, carrier concentration, drop diameters, etc., for similar systems. Studies on ESPLIM were conducted with the aim of demonstrating the effectiveness of this new separation process and to develop a simple transport model for metal permeation. In the ESPLIM process, a high electrical field (3-5 kV A.C.) is used for phase dispersion. This system consists of a rectangular reactor filled with membrane solution divided into extraction and stripping cells by a centrally placed integrated type baffle which also acts as an electrode. Two more electrodes were placed in the extraction and stripping cells, where feed and strip phases are introduced from the top of the reactor. When high electrical field is applied across the electrodes, fine droplets of feed and strip are formed and are dispersed in extraction and stripping cells where simultaneous extraction and stripping occurs. The process can be viewed as simultaneous counter current extraction and stripping. The aqueous drops coalesce in the settlers at the bottom of the reactor and are removed continuously. Steady state mass transport model proposed for ESPLIM system accounts for the vertical counter-current extraction and stripping processes taking place in the extraction and stripping cells, together with the lateral transport process of the metal-complex and carrier across the two cells through the integrated baffle zone. The model equations were solved analytically to obtain concentration profiles as a function of the height of the reactor. The required parameters such as mass transfer coefficients, diffusion coefficients etc. were estimated using different correlations. Model predictions agreed remarkably well with the experimental data under various process conditions. From this investigation, it was found that ESPLIM is a simple, efficient and economical process and can be applied in a variety of situations. Based on a suitable combination of solvent extraction, dispersion and liquid membrane technique, a new type of separation system called " Unified Liquid Membrane " was developed. The ULM unit was designed and fabricated, and experiments were conducted to evaluate its performance. The ULM is basically derived from ESPLIM by changing the reactor, baffle design and dispersion technique. Aqueous feed and strip phases were atomized using compressed air through a fine nozzle and are dispersed on either side of an integrated baffle plate that divides the reactor into extraction and stripping cells. Tapering bottom of the reactor reduces the dead volume of the liquid in the settlers and the baffle plate remarkably reduces the leakage problem as well as the resistance through the baffle. Experiments were conducted using LIX 64N and Alamine 336 as carriers for copper and chromium and / or zinc. Mass transport model proposed considers both chemical and phase equilibria in extraction and stripping cells, vertical and lateral transport of carrier and complex across the extraction and stripping cells through the baffle zone. The model equations were solved using initial conditions at the top of the reactor, and equilibrium data for extraction and stripping cells. Effect of various experimental conditions and process parameters was simulated using this model and the model predictions are found to be in excellent agreement with the experimental data. The ULM system developed in this investigation overcomes the major limitations encountered with the other types of liquid membranes while retaining all the advantages of this technology. The problem of high mass transfer resistance from bulk phase to metal permeation as in the case of BLM was eliminated by good phase dispersion. Additional resistance to mass transport from solid membrane as in the case of SLM was removed by using an integrated baffle which also avoids problems of membrane instability, pore clogging and selectivity. The complex problems of emulsification and demulsification were completely eliminated making the system much simpler and efficient. Very good phase dispersion was obtained by atomization without the need for either stirring the whole system or application of high electrical field in the reactor. The membrane liquid within the integrated baffle elements allows easy transport of different species between extraction and stripping cells while completely preventing the mixing of the two aqueous phases. The problems of leakage, swelling and occlusion were avoided due to very short residence time of the aqueous drops in the reactor. It was found that the new ULM configuration is simple, elegant, highly efficient and superior to the other types of liquid membrane systems.

L’aménagement des systèmes d’assainissement conventionnel des eaux usées domestiques entraine actuellement la déplétion de ressources naturelles et la pollution des milieux récepteurs. L’utilisation d’une approche écosystémique plus globale telle que l’Assainissement Écologique, visant la fermeture du cycle de l’eau et des éléments nutritifs (phosphore et azote), contenus dans les excréments, par leur réutilisation à travers l’agriculture, permettrait d’améliorer de façon écologique cette situation. Toutefois, ce paradigme émergent est peu enseigné aux professionnels de l’aménagement responsables de sa planification, surtout au niveau de son application dans les pays développés nordiques. C’est pourquoi, afin d’améliorer la planification de ce type de système, il faut informer ces derniers des pratiques les plus adéquates à adopter. Pour y arriver, un scénario d’aménagement type a été développé à partir d’une revue exhaustive de la littérature et de l’analyse des données en se basant sur les recommandations de l’approche en fonction du contexte étudié. Ce scénario aidera les professionnels à mieux comprendre l’Assainissement Écologique et son aménagement. Il représente alors un point de départ pour les discussions interdisciplinaires et participatives que celui-ci requiert. En conclusion, il y a encore de nombreux manques d’informations concernant l’utilisation de traitements alternatifs dans les climats nordiques et l’acceptation de ceux-ci par les usagers. De plus, les cadres législatifs demeurent un obstacle considérable à l’aménagement d’un tel système. Cette recherche permet cependant de démystifier l’approche auprès des professionnels et pourrait aider à modifier certains cadres législatifs afin d’y intégrer sa philosophie. / At the moment, the planning of conventional sanitation systems for the treatment of domestic wastewater is responsible for the depletion of natural resources and pollution of receiving waters. A more holistic approach, respecting the local ecosystem, such as the new paradigm of Ecological Sanitation would greatly improve this situation. The idea pursues the closure of water and nutrients (nitrogen and phosphorus found in the human excreta) cycles through their reuse in agriculture. However, this new approach remains relatively unknown except for a few planning professionals responsible for the implementation of sanitation systems especially in the context of northern industrialized countries. Therefore to enhance the design of this kind of system, there is a need to educate and inform these professionals on more suitable treatment options to adopt. To achieve this, a planning scenario has been developed using a literature review and analysis of the data using a grid based on the recommendations of the paradigm when planned in this particular context. This scenario will help the professionals to better understand the philosophy of this approach and its implementation. It will represent a starting point for the interdisciplinary and participatory discussions that this approach demands. In conclusion, there is still a lack of knowledge surrounding the use of certain alternative options and their degree of acceptance by the public. Moreover, the legislation surrounding sanitation represents a significant obstacle to the implementation of this sort of alternative system. Still, this research helps the planning and design professionals demystify the new paradigm and may even be helpful in the modification of laws for the integration of its philosophy.