The contribution and status of physical removal in sustainable management of water hyacinth

Physical control of water hyacinth consists of removing the plants from the water by hand or machines. It is considered over effetive because it involves removing the whole plants from water. The first attempt on physical control was in 1992 when weed infestation was causing serious problems to the fishing communities in Lake Kyoga. The fishermen had problems of accessing the lake as huge masses of mobile weed blocked landing sites. Furthermore, the fishers lost their nets, which were swept away by mobile water hyacinth. As a result, an integrated control strategy involving physical control (manual and mechanical removal) was put in place. Through this method, the fishers were able to open up access routes to fishing grounds even though weed mats often reblocked the access routes. In the infested lakes, manual removal offered remedial relief to fish Iandings and other access sites. Sites of strategic importance such as hydro-electric power generation dam, water intake points and docking points which had large masses of water hyacinth required heavy machinery and mechanical harvesters were used at these sites.

Status of kariba weed (Salvinia molesta) infestation, its impacts and control options on Uganda’s water systems

Kariba weed (Salvinia molesta) is an invasive alien waterweed that was first recorded in Uganda in sheltered bays of Lake Kyoga in June 2013. This waterweed has become a common feature on Lake Kyoga and its associated rivers, streams and swamps, and has spread to other lakes notably Kwania and Albert in addition to Lake Kimira in Bugiri district.

Socio-economic aspects of Nabugabo satellite lakes, fisheries and their implications for management

A number of fish species once native only to Lakes Victoria and Kyoga have considerably declined over the years, and in some cases disappeared, due to over exploitation, introduction of exotic species especially the Nile Perch, and environmental degradation resulting from human activities. Some of the species have been observed to survive in satellite lakes in the Victoria and Kyoga Lake basins. The Nabugabo satellite lakes contain the endemic Cichlid fish species, Oreochromis esculentus and two haplochromine species previously found only in Lake Nabugabo. There is, therefore, need to conserve these species by ensuring sustainable use and management of the resources. The study revealed that the Nabugabo lakes provide a range of socio-economic benefits accruing from fishing, farming, logging, resort beach development and watering of animals. However, although these activities impact on the lakes ecosystems, the participation of resource users in management is limited because of the weak local management institutions operating on the lakes, hence the need to strengthen them through capacity building. It is recommended that Government should work jointly with the beach committees and fishing community in a participatory way to eliminate the use of destructive fishing practices and control the other environment degrading activities.

Small-scale fishing in Central American indigenous people: governance, tenure and sustainable management of marine resources

This research develops four case studies on small-scale fisheries in Central America located within indigenous territories. The ngöbe Bugle Conte Burica Territory in the south of Costa Rica, the Garífuna territory in nueva Armenia Honduras, the Rama territory in Nicaragua and the ngöbe Bugle territory in Bocas del Toro, Panamá. This is one of the first studies focusing on indigenous territories, artisanal fisheries and SSF guidelines. The cases are a first approach to discussing and analyzing relevant social and human rights issues related to conservation of marine resources and fisheries management in these territories. The cases discussed between other issues of interest, the relationships between marine protected areas under different governance models and issues related to the strengthening of the small-scale fisheries of these indigenous populations and marine fishing territories. They highlight sustainability, governance, land tenure and access to fishing resources, gender, traditional knowledge importance and new challenges as climate change.

Preparation of environmental monitoring plan pattern for surface water quality in Iran (Case study: Gharehsou River)

Using water quality management programs is a necessary and inevitable way for preservation and sustainable use of water resources. One of the important issues in determining the quality of water in rivers is designing effective quality control networks, so that the measured quality variables in these stations are, as far as possible, indicative of overall changes in water quality. One of the methods to achieve this goal is increasing the number of quality monitoring stations and sampling instances. Since this will dramatically increase the annual cost of monitoring, deciding on which stations and parameters are the most important ones, along with increasing the instances of sampling, in a way that shows maximum change in the system under study can affect the future decision-making processes for optimizing the efficacy of extant monitoring network, removing or adding new stations or parameters and decreasing or increasing sampling instances. This end, the efficiency of multivariate statistical procedures was studied in this thesis. Multivariate statistical procedure, with regard to its features, can be used as a practical and useful method in recognizing and analyzing rivers’ pollution and consequently in understanding, reasoning, controlling, and correct decision-making in water quality management. This research was carried out using multivariate statistical techniques for analyzing the quality of water and monitoring the variables affecting its quality in Gharasou river, in Ardabil province in northwest of Iran. During a year, 28 physical and chemical parameters were sampled in 11 stations. The results of these measurements were analyzed by multivariate procedures such as: Cluster Analysis (CA), Principal Component Analysis (PCA), Factor Analysis (FA), and Discriminant Analysis (DA). Based on the findings from cluster analysis, principal component analysis, and factor analysis the stations were divided into three groups of highly polluted (HP), moderately polluted (MP), and less polluted (LP) stations Thus, this study illustrates the usefulness of multivariate statistical techniques for analysis and interpretation of complex data sets, and in water quality assessment, identification of pollution sources/factors and understanding spatial variations in water quality for effective river water quality management. This study also shows the effectiveness of these techniques for getting better information about the water quality and design of monitoring network for effective management of water resources. Therefore, based on the results, Gharasou river water quality monitoring program was developed and presented.

Separation and identification fresh water leeches of waters resources in Kordistan Province

In the primary studying, known leeches have included into free living and parasitic which the parasitic group, besides of direct impacts like: growth detraction, anemia, making wound in the connecting part with the skin, with making plat for secondary bacterial and molding infections in the toll place, is able to cause to transfer blood flagellate and virus to the fish too. Therefore, by accusing information related to fauna leeches of each area a risk factor from the viewpoint of the possibility of being or accusing transferred diseases by these leeches, one can predict and forehand about them. Freshwater leeches of Iran to present accurate recognition (morphological, molecular) have not been, and there are some limited reports from different parts of the country about them. One of the areas that its leeches have not been identified yet is Kurdistan, By having five latrines and big permanent rivers and 32000 springs and a lot of deep and semi-deep wells and this province is a convenient bed for growing aquatics in the country. Therefore, identifying risk factors for development of aquaculture on water resources is one important factor to access achieving development goals. For recognizing leeches of this province, some samples from 10 stands were token. Samples from under stones, sticking to the fish, turtles, plants and solid substances in the water were separated and after recording their physical characteristics, calming with 10% ethylic alcohol with 10% formalin become fixed and after painting with Carmen acetic acid by standard keys for 7 species of Helobdella stagnalis, Placobdella costata, Hemiclepsis marginata, Erpobdella octoculata, Hirudo medicinalis, Dina lineate lineata have been identified and described. Which Helobdella stagnalis has the highest distribution in the province and the minimum one is Hirudo medicinalis. However, that the data obtained in leeches in Kurdistan is a relatively complete collection in this research, recognizing fauna of these areas needs more studying. The Placobdella costata and Hemiclepsis marginata sticking to the fish were separated among identified species which showed that these are parasites for the fish. The sticking area of those leeches to the skin was accompanied with scales cast, damage to mucous membranes beneath the parasite and bleeding Was associated with Histopathology studying effect includes observing break and disconnection in the leech connecting place to the epithelial layer of epidermis in the skin, destroyed nucleus in skin Epithelial cells with observing necrosis in ulcerative place become of the leech and the sub acute inflammated penetration until acute necrosis with opening in Dermis layer is observable. Kidney of this fish have changes such as: proliferation, like proliferative kidney disease with increasing proliferative glomerular cells and increasing in membranous cells in Capillary corpuscle, observing necrotic cells in haematopoietic tissue of kidney along with increasing in infiltration of leukocyte's cells generally mono nucluars such as lymphocytes and less poly morpho nucluars such as neutrophiles that are symptoms of disorders causing anemia become of nourishing and sucking blood by the leech and creating a chronic kidney infection that originally root is in another place like the skin. Also Hemorrhagic anemia causes losing RBC's is because of using the host blood by the leech. (In this situation, one can see immature RBC red cells in Peripheral blood. To identify potential carriers of the leech to the viruses, after finding them in recorded stands and putting them in 75% ethanol for viruses cause IPN, VHS, IHN, they were tested by PCR that the conclusion of these experiments approved IPN virus in Hemiclepsis marginata and Hirudo medicinalis. This kind of leeches can act like a mechanical carrier and causing spreading the agent of this disease. It is worth mentioning that studying the pathogenicity of this virus for aquaculture sources, mentioned before needs more research. During the study of infected fish with leeches that was done after preparing bloody slides and staining them, no case blood parasites was observed. During a research about infecting fish experimentally to known leeches it become clear that 5 days after being in aquarium including leeches, samples of sticking Hirudo medicinalis leech to the golden carp with scales cast were observed. Including leeches to the fish started with molting the scales in the sticking area in the fish and fish become too uneasy and by rubbing themselves to the malls and things inside the aquarium, tried to separate them. Finally, after around 30 hours, leeches penetrate the skin, feeding from blood and tissue liquids and cause mortality the fish and then they become separated from them. If the corpse of these fish stayed in the aquarium, the Helobdella stagnalis and Erpobdella octoculata would start feeding them.

Optimization of flocculation process and continuous filtration for sea water primary treatment filtration to reduce SDI for entree to reverse osmosis system

Today , Providing drinking water and process water is one of the major problems in most countries ; the surface water often need to be treated to achieve necessary quality, and in this way, technological and also financial difficulties cause great restrictions in operating the treatment units. Although water supply by simple and cheap systems has been one of the important objectives in most scientific and research centers in the world, still a great percent of population in developing countries, especially in rural areas, don't benefit well quality water. One of the big and available sources for providing acceptable water is sea water. There are two ways to treat sea water first evaporation and second reverse osmosis system. Nowadays R.O system has been used for desalination because of low budget price and easily to operate and maintenance. The sea water should be pretreated before R.O plants, because there is some difficulties in raw sea water that can decrease yield point of membranes in R.O system. The subject of this research may be useful in this way, and we hope to be able to achieve complete success in design and construction of useful pretreatment systems for R.O plant. One of the most important units in the sea water pretreatment plant is filtration, the conventional method for filtration is pressurized sand filters, and the subject of this research is about new filtration which is called continuous back wash sand filtration (CBWSF). The CBWSF designed and tested in this research may be used more economically with less difficulty. It consists two main parts first shell body and second central part comprising of airlift pump, raw water feeding pipe, air supply hose, backwash chamber and sand washer as well as inlet and outlet connections. The CBWSF is a continuously operating filter, i.e. the filter does not have to be taken out of operation for backwashing or cleaning. Inlet water is fed through the sand bed while the sand bed is moving downwards. The water gets filtered while the sand becomes dirty. Simultaneously, the dirty sand is cleaned in the sand washer and the suspended solids are discharged in backwash water. We analyze the behavior of CBWSF in pretreatment of sea water instead of pressurized sand filter. There is one important factor which is not suitable for R.O membranes, it is bio-fouling. This factor is defined by Silt Density Index (SDI).measured by SDI. In this research has been focused on decreasing of SDI and NTU. Based on this goal, the prototype of pretreatment had been designed and manufactured to test. The system design was done mainly by using the design fundamentals of CBWSF. The automatic backwash sand filter can be used in small and also big water supply schemes. In big water treatment plants, the units of filters perform the filtration and backwash stages separately, and in small treatment plants, the unit is usually compacted to achieve less energy consumption. The analysis of the system showed that it may be used feasibly for water treating, especially for limited population. The construction is rapid, simple and economic, and its performance is high enough because no mobile mechanical part is used in it, so it may be proposed as an effective method to improve the water quality and consequently the hygiene level in the remote places of the country.

Thermal and exergy analysis for evaluation and optimization of performance of cooling towers for fresh water and seawater

In this study, thermal, exergetic analysis and performance evaluation of seawater and fresh wet cooling tower and the effect of parameters on its performance is investigated. With using of energy and mass balance equations, experimental results, a mathematical model and EES code developed. Due to lack of fresh water, seawater cooling is interesting choice for future of cooling, so the effect of seawater in the range of 1gr/kg to 60gr/kg for salinity on the performance characteristics like air efficiency, water efficiency, output water temperature of cooling tower, flow of the exergy, and the exergy efficiency with comparison with fresh water examined. Decreasing of air efficiency about 3%, increasing of water efficiency about 1.5% are some of these effects. Moreover with formation of fouling the performance of cooling tower decreased about 15% which this phenomena and its effects like increase in output water temperature and tower excess volume has been showed and also accommodate with others work. Also optimization for minimizing cost, maximizing air efficiency, and minimizing exergy destruction has been done, results showed that optimization on minimizing the exergy destruction has been satisfy both minimization of the cost and the maximization of the air efficiency, although it will not necessarily permanent for all inputs and optimizations. Validation of this work is done by comparing computational results and experimental data which showed that the model have a good accuracy.