M.Sc. / The occurrence of invertebrates in drinking water supplies is a common consumer complaint with studies showing that very few drinking water distribution networks are totally free of organisms. A detailed investigation of different types of metazoan animals in the drinking water supply networks of South Africa has not been undertaken. In limited worldwide studies, invertebrates (mainly Amphipoda, Chironomidae, Cladocera, Copepoda and Ostracoda) have been detected in produced drinking water. In countries that have started monitoring these organisms, the quality of the produced water has improved due to the improved methods of filtering. The occurrence of “worms” (Nematodes and Diptera) and Crustaceans decreases the aesthetic value of the drinking water, and pathogenic organisms, which may also be associated with them, can affect human health. Limited reference works have been compiled during the conducted studies on drinking water distribution networks throughout the world. All fresh water invertebrates have the potential to be passed into the drinking water supply network (Rising mains, pipelines, reservoirs, and consumer taps). There are few complete reference works available for fresh water invertebrates occurring in the fresh water sources and those of Southern Africa. Therefore, there are no reference works regarding fresh water invertebrates that can be used to monitor drinking water supply networks in South Africa. / Prof. J.H.J. van Vuren

Thesis: Sc. D., Massachusetts Institute of Technology, Department of Civil Engineering, 1975 / Vita. / Bibliography: leaves 266-271. / Sc. D. / Sc. D. Massachusetts Institute of Technology, Department of Civil Engineering

Although deforestation remains widespread in the tropics, many places are now experiencing significant forest recovery, offering an optimistic outlook for natural ecosystem recovery and carbon sequestration. Natural forest regeneration is a key component of global ecosystem restoration scenarios. Regenerated forests, however, may not persist so a more nuanced understanding of the drivers of forest persistence in the tropics is critical to ensure the success reforestation efforts and carbon sequestration targets. Furthermore, the maintenance of native forests, including young second-growth ones, is essential for the continuous provision of a myriad of ecosystem services that we, as a society, rely on. More specifically, native forests play a crucial role in watershed protection and forest cover loss via changes in land use can lead to deterioration of water quality. Ensuring a sufficient and adequate supply of water for humans and ecosystems is a pressing environmental challenge and land use decisions can severely degrade stream water quality and compromise water supply. This dissertation focusses on two pressing current issues, the dynamics of tropical forest regeneration and the effects of land use on water resources. First, I use a long-term series of detailed land cover data to study forest cover trajectories and persistence of regenerated forest in the Brazilian Atlantic Forest (AF), a restoration hotspot. Secondly, I use 20 years of stream water quality data combined with land cover information to investigate the effects of land cover composition on water resources in the state of São Paulo, Brazil. In Chapter 1, I investigate forest cover trajectories in 3,014 municipalities and quantify the carbon sequestration potential of forest regeneration in the AF. I found that deforestation reversals were the prevalent trend in the region (38%) but concomittant reforestation reversals (13%) suggest that these short-term increases in native forest cover do not necessarily translate into persistent trends, which limited carbon sequestration from reforestation to less than one third of its potential. In Chapter 2, I quantify forest regeneration in the AF and study its persistence. I mapped over 4.47 Mha of native forest regeneration in the region between 1985 and 2019, of which, two thirds persisted until 2019 (3.1 Mha). The relatively low persistence of second-growth forests suggests a rapid turnover of regrowing forests under certain conditions. In Chapter 3, I combine stream water quality data with detailed and land cover information to investigate the effects of landscape composition on the quality of water resources in the state of São Paulo, Brazil. I found that human dominated watersheds had lower overall water quality when compared to conserved ones, with urban cover showing the most detrimental impacts on water quality, while forest cover was associated with a better overall water quality across the studied watersheds. Finally, in Chapter 4, I examine temporal changes in water quality and their association with land use and sewage treatment also in the state of São Paulo. I show that a large proportion of stream water samples failed to meet legal thresholds for at least one water quality metric and that urbanization and agricultural activity led to deterioration of water quality over time, while sewage treatment infrastructure was an important factor in improving water quality. Overall, my dissertation underscores the importance of developing policies that promote second-growth forest persistence to ensure the success of future restoration efforts. It also highlights the need to need to plan and manage landscapes to improve water quality and reduce the growing costs of water treatment, including restoring native forest cover, which is a cost-effective intervention to sustain adequate water quality.

A study was made of existing methods of management, treatment and disposal of water and wastewater effluents at a large aerospace facility (Martin Marietta Aerospace) in Central Florida. Water consumption and handling were evaluated, with emphasis being placed on the handling of plating wastes, since they are the main contributor of industrial wastewater pollutants at the facility. The flow, storage, and treatment of the plating wastes were studied. Literature concerning plating wastes was surveyed to determine the latest "state of the art" on handling of plating pollutants. Then, the "state of the art" processes were compared with the existing processes to determine the need for improvements. This comparison resulted in recommendations for improvements to the existing facility.

In searching for a subject to meet the M. S. Degree Research Report requirements, I had several objectives in mind. I wanted (1) a project with relevancy in the environmental field which would broaden my understanding of the environmental systems which I have studied, (2) a subject which would allow me to apply some of the Principles which I have learned in Operations Research , and (3) a project which had good practical application. With these objectives in mind, I reviewed the suggested topics presented by the Faculty and selected the FTU Water and Wastewater System Analyses topic which was recommended by Dr. Y. A. Yousef. After selecting the topic I became very interested in the application of Management Information Systems (MIS) and discussed with Mr. C. S. Bauer, the possibility of utilizing such a program to evaluate the data which I had accumulated. He concurred that this would be a good application of a MIS and encouraged my use of it. He provided me with a basic MIS program which he and his IEMS 496-13 class of 1971 had developed . To meet the requirements of this study it was necessary to add some programs and make modifications to the basic programs which provided me with an extensive involvement in computer programming and MIS operations. The application and use of the MIS has become an important part of this research paper. I have learned much in analyzing the FTU Water and Wastewater Systems and in applying the FTU Water and Wastewater Systems and in applying the Management Information System. It appears that a continuation of these studies with an increase of scope to encompass electrical and other mechanical utilities would be desirable. It would also appear that this study could have practical value in the management of the present utility systems and that FTU might elect to continue this or a similar MIS program as a part of the utilities operations. This type study should also have potential application for analyzing municipal and government operated facilities.

Properties and characteristics of colloidal systems are reviewed with a discussion of colloid systems to be found in natural and wastewaters. Current electric and magnetic field theory are reviewed and summarized to provide practical application of the theory to engineering problems in the environmental field. Literature of colloidal reactions to electrical and magnetic fields is discussed and reviewed to ascertain areas of potential application of electric and magnetic phenomena to natural and wastewater treatment systems having objectionable colloid suspensions. It is concluded that application of electrical fields (electrophoresis) does not currently hold much promise for practical applications in water treatment systems. However, and understanding of colloid systems and electrophoresis is strongly recommended for personnel involved in chemical treatment of waters. It is shown that there has been considerable research and many applications of magnetic field treatment of waters by the Russians, most analysis of which is performed in an empirical manner that tends to cloud the phenomena with an aura of mysticism. Practical applications of magnetic field phenomena to water treatment systems involving ferromagnetic colloidal suspensions appears promising and research into this area is recommended.

A stochastic dynamic constituent transport model was developed, capable of simulating the operation of a water distribution system containing pumps and storage tanks, and subject to random demands and contaminant inputs. Long term operation of a hypothetical small town water supply system containing one pump station and one storage tank was simulated while the system was subjected to external contaminant inputs. Repeated simulations were made under different regimes of external contamination applied to the tank, the pump station and at system nodes, and internal contamination representing biofilm effects based on assumed relationships between flow velocities and bioflim cell detachment. Seven sampling plans representing regulatory requirements and industry practice were applied during the simulation to evaluate their ability to detect the contamination under a presence/absence criterion. The simulations were able to identify contamination patterns and provide information useful in the definition of sampling plans. Time of sampling was found to be as important as location. This was true both within the monitoring period, and particularly within the diurnal cycle of demand. Spreading samples over different days within the monitoring period rather than sampling all on one day, always improved contaminant detection. Detection by plans based on fixed times and locations were very sensitive to those times and locations. There was no best plan suitable for all situations tested. The better sampling plans were those that captured the temporal and spatial contamination patterns present in the system. No consistent advantage was noted from sampling in proportion to population served or in locating sampling nodes systematically instead of randomly. The location and timing of sampling for most plans could be improved with the knowledge of actual contamination patterns and timing provided by the model. The presence of a storage tank was found to have a strong influence on hydraulic patterns and the location and timing of contamination reaching different parts of the system. / Ph. D.

Chlorine dioxide is used as both a pre-oxidant and/or a post-disinfectant in several water treatment plants in the United States. Chlorine dioxide is associated with its byproducts chlorite and chlorate. Chlorine dioxide, chlorine, chlorite and chlorate were sampled in four distribution systems where chlorine dioxide is used for disinfection purposes: Charleston, WV, Columbus, GA, New Castle, PA, and Skagit, WA. The fate of chlorine dioxide and its by-products in distribution systems is discussed. A constituent transport model (TRAK) was applied to New Castle, PA distribution systems to assess times of travel. No relationship was found between the concentrations of chlorine, chlorine dioxide, chlorite and chlorate and the computed travel times. Water treatment plant and distribution system data received from Galveston, TX where the use chlorine dioxide has being tested is analyzed and discussed. Median chlorine dioxide concentrations are relatively constant in distribution systems with a value of approximately 0.2 mg/L; however, chlorine dioxide dosages applied at the treatment plant can induce different concentrations in the distribution system. Median chlorite concentrations in distribution systems range from 0.5 to 0.8 mg/L while median chlorate concentrations are generally lower in a range between 0.1 to 0.3 mg/L. The effects of distribution systems skeletonization in constituent transport modeling are also presented. Skeletonization does not affect significantly computed times of travel when the median percentage of constituent has to be detected. However, depending on the layout of each distribution system, small variations can be observed. / Master of Science

The purpose of this study was to investigate selective operational parameters and their effect on activated sludge settling and dewatering rates. Several laboratory scale reactors were used in this study and fed with various synthetic substrates. The sludges produced from these reactors were used to examine sludge settling and dewatering characteristics as the selected operational parameters were varied. This study intended to determine if: (1) qualitative shock loadings affect sludge dewatering and settling and will biological systems recover quickly under various conditions; (2) aeration basin dissolved oxygen concentration affects sludge settling and dewatering characteristics; (3) biopolymer content can be correlated with sludge dewatering rates such that biopolymer content can be used as a parameter to monitor sludge dewatering characteristics. Results from this study indicated that the shock loadings considered here significantly alter the sludge settling and dewatering characteristics of an activated sludge population. Shock loadings may cause shifts in the bacterial population, allowing undesirable microorganisms to predominate but activated sludge systems can recover from shock loadings caused by the introduction of a different substrate. Also, it was seen that activated sludge dewatering is directly affected by the dissolved oxygen level in the aeration basin and the minimum level required is 2.0 mg/L in a completely-mixed system. A definite relationship was noted between biopolymer production and sludge dewatering with high biopolymer content correlating with poor sludge dewatering and low biopolymer content correlating with good sludge dewatering. / Master of Science / incomplete_metadata

A systems approach, utilizing a deterministic hydrologic simulation model and an optimization model, was developed to evaluate and optimize cropland Best Management Practices (BMPs). The approach consisted of using the Finite Element Storm Hydrograph Model (FESHM) to simulate runoff and sediment yield from a series of design storms with known return periods. The design storm simulations were the basis for sediment distributions representing unique cropland areas and management practices. The distributions were evaluated to obtain average annual sediment yields which were used as activity coefficients in a linear programming (LP) optimization model. The LP model selected the set of cropland management practices that minimized total sediment yield while meeting economic and agricultural production constraints. A postoptimality analysis was performed on the optimal solution to examine the effects of variations in: (1) income levels representing subsidy, and (2) sediment coefficients. The optimal solution was found to be insensitive to reductions in income levels (representing subsidy) and extremely sensitive to changes in the sediment coefficients. Limitations of the systems procedure models were discussed along with suggestions for improving the sediment coefficients and their practical usage. / Master of Science