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Made available in DSpace on 2014-12-17T15:03:33Z (GMT). No. of bitstreams: 1 MoisesAFQ_DISSERT.pdf: 1322817 bytes, checksum: d69733a37de991cb265f0cf0939bee27 (MD5) Previous issue date: 2014-02-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This research evaluated the microalgae removal produced in a stabilization pond system using biofilters as post-treatment, besides characterizing the effluents of stabilization ponds and filters in relation to concentrations of algal biomass (chlorophyll a and suspended solids), organic matter (BOD and COD), total phosphorus, orthophosphate, pH and dissolved oxygen, and tried to correlate physicochemical parameters with chlorophyll "a". It was held at the Ponta Negra ETE which is constituted by three stabilization ponds, with a primary facultative pond and two of maturation. For the algae removal were used two submerged bio-filters: the filter FPF (Facultative Pond Filter), fed with facultative pond effluent; and the filter MPF (Maturation Pond Filter), fed with second maturation pond effluent. The filling material of both filters was predominantly gravel no. 2, although it contains portions of gravel no. 1 and no. 3. The filters operating conditions were bad, they were nearly 10 years without maintenance, without cleaning or removal of sludge since the time of its construction, and part of the filling material may be obstruct. Despite poor operating conditions were obtained satisfactory results, in level of posttreatment. Removal efficiencies in relation to BOD and COD were 7 and 25% in FPF and 9 and 19% and in MPF, respectively. In relation to TSS efficiencies in MPF and FPF were 37 and 20%, respectively. As for the chlorophyll "a" removal, the FPF efficiency was 44% and the MPF was 40%. There was 50% of consumption of dissolved oxygen, on average, within the filters. Two profiles were performed in the filters, and it was possible to conclude that variations throughout the day were not statistically significant, and that, regardless of the time of collection, they would have the same representation comparing to the time of data collection (7 am) and the daily average, although individual variations throughout the day have been shown to be significant. Another important observation is that the correlations between Chlorophyll a and TSS were bigger and more significant in the effluent of the filters than in the effluent of the ponds / A pesquisa avaliou a remo??o das microalgas produzidas em um sistema de lagoas de estabiliza??o utilizando biofiltros como p?s-tratamento, al?m de caracterizar os efluentes de lagoas de estabiliza??o e dos filtros no tocante ?s concentra??es de biomassa algal (clorofila a e s?lidos suspensos), mat?ria org?nica (DBO e DQO), ortofosfato, f?sforo total, pH e oxig?nio dissolvido, e buscou correlacionar os par?metros f?sico-qu?micos com a clorofila a . Foi realizada na ETE Ponta Negra que ? constitu?da por tr?s lagoas de estabiliza??o, sendo uma lagoa facultativa prim?ria e duas de matura??o. Para a remo??o das algas, foram utilizados dois biofiltros submersos: o filtro FLF -alimentado com efluente da lagoa facultativa; e o filtro FLM - alimentado com efluente da segunda lagoa de matura??o. O material de enchimento de ambos os filtros foi predominantemente brita n? 2, apesar de conter por??es de brita n? 1 e n? 3. As condi??es operacionais dos filtros eram p?ssimas, pois estavam h? quase 10 anos sem manuten??o, sem limpeza ou remo??o do lodo desde a ?poca da constru??o, podendo parte do material de enchimento estar colmatado. Apesar das condi??es operacionais prec?rias foram obtidos resultados satisfat?rios, em n?vel de p?s-tratamento. As efici?ncias de remo??o em rela??o ? DBO e DQO foram de 7 e 25% no FLF e 9 e 19% no FLM, respectivamente. Em rela??o aos SST as efici?ncias no FLF e FLM foram de 37 e 20%, respectivamente. Quanto ? remo??o de clorofila a , a efici?ncia no FLF foi de 44% e no FLM foi de 40%. Houve o consumo de 50% do oxig?nio dissolvido, em m?dia, no interior dos filtros. Foram realizados dois perfis nos filtros, e foi poss?vel concluir que as varia??es ao longo do dia n?o foram estatisticamente significativas, e que, independentemente do hor?rio da coleta, teriam a mesma representatividade ao comparar com o hor?rio da coleta da pesquisa (7 horas da manh?) e a m?dia di?ria, embora as varia??es pontuais ao longo do dia tenham se mostrado expressivas. Outra importante observa??o foi que as correla??es entre Clorofila a e SST foram maiores e mais significativas nos efluentes dos filtros do que nos efluentes das lagoas

M. Tech. (Department of Civil Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / Over time, the quality standard of stormwater in the City of Ekurhuleni (CoE) has deteriorated due to industrial, commercial, residential and farming activities. Stormwater quality directly impacts the treatment chain of potable water, and therefore, it should be kept in check at all stages. Innovations in the biofiltration process can provide useful, practical solutions to overcome crucial stormwater pollution problems. In 2013, the CoE developed stormwater design guidelines and standards to be implemented for the design of stormwater management, which include the principles of Water Sensitive Urban Design (WSUD) and Sustainable Urban Drainage Systems (SuDS) in particular. The CoE stormwater design guidelines and standards do not provide details on how the city plans to implement SuDS treatment trains to reduce stormwater pollution experienced by the city. This study aimed to verify the efficiency and effectiveness of vegetated biofilters on the stormwater treatment using CoE – Olifantsfontain's natural stormwater and to determine the most suitable vegetation to be used in the region. The CoE experimental case study was conducted to assess the efficiency of selected vegetated biofilters in lowering the concentration of orthophosphate (PO4-3), ammonium (NH4+), and nitrate (NO3-) from Tembisa/Olifantsfontain stormwater. In the experimental setup, six selected plant species were planted into 30 vegetated biofilter columns, namely: Agapanthus praecox (Dryland plant), Carpobrotus edulis (Dryland plant), Stenotaphrum secundatum (Dryland plant), Zantedeschia aethiopica (Wetland plant), Typha capensis (Wetland plant) and Phragmites australis (Wetland plant). The six species were grouped according to general habitats, i.e. three wetland and three dryland plants. Wetland plants were planted into fifteen vegetated biofilters, and dryland plants were also planted on another fifteen vegetated biofilters. The biofilters contained layers of sandy loam soil, coarse and and gravel sand. Each biofilter had a designated inlet and outlet section fitted with a gate valve to control retention time. The raw stormwater consisting of natural nutrient pollutants was applied to each vegetated biofilter through the inlet section. The samples were collected from the inlet and outlet of the six grouped vegetated biofilters during the month of June. All six plant species reduced outflow concentrations of PO4-3 and NH4+ by an average of 99% and 98%, respectively. The results also show that all plant species excluding Phragmites australis were able to reduce NO3- with outflow concentrations being reduced by an average of 58%. From the results obtained, it may be concluded that all the six plant species may be suitable variants to be applied as biofilter material for the purposes of treating urban stormwater in the CoE. The reason is that the determined removal efficiencies for bio-retention fall within 50% – 60% for PO4-3, and 40% - 50% for NH4+ and NO3- respectively. The results also show that if the plant species were applied for SuDs in the CoE, there could be a great improvement in the urban stormwater quality with the consequent improvement in both surface and groundwater quality of the receiving water bodies in the area. Regardless of the nutrient removal by selected plant species, the inclusion of vegetation in a field setting would slow flow rates and thus encourage infiltration into the soil, improve water quality, and support urban biodiversity. In the CoE, all the selected species could be used in the SuDS treatment trains targeting PO4-3, NH4+ and/or NO3-. The case study results provide a informed records for the CoE in the future/intended application SuDs in the upgrade/rehabilitation of its stormwater system.

Phytoplankton blooms compromise the quality of freshwater ecosystems and the efficient processing of water by treatment works worldwide. This research aims to determine whether in-situ filamentous biofiltration processes mediated by living roots and synthetic filters as media can reduce or remove the phytoplankton loading (micro-algae and cyanobacteria) prior to a potable water treatment works intake. The underlying biofiltration mechanisms were investigated using field and laboratory studies. A novel macroscale biofilter with three plant species, named the "Living-Filter", installed in Farmoor II reservoir, UK, was surveyed weekly for physicochemical and biological variables under continuous flow conditions during 17 weeks. The efficiency of a mesoscale biofilter using the aquatic plant Phalaris arundinacea and synthetic filters, was tested with Microcystis aeruginosa under continuous flow conditions and in batch experiments. The 'simultaneous allelochemical method' was developed for quantifying allelochemicals from Phalaris in aqueous samples. Microscale studies were used to investigate biofilter allelochemical release in response to environmental stressors and Microcystis growth inhibition in filtered and unfiltered aqueous root exudate. Results demonstrate that the removal of phytoplankton biomass by physical mechanisms has a removal efficiency of ≤45% in the "Living-Filter" (filamentous biofilter plus synthetic fabric) and that the removal of Microcystis biomass using only biofilters was 25%. Chemical mechanisms that reduce Microcystis cell numbers are mediated by allelochemicals released from biofilter roots. Root exudate treatments on Microcystis revealed that Microcystis growth is inhibited by allelochemicals, not by nutrient competition, and that protists and invertebrates play a role in removing Microcystis. Filamentous biofilters can remove phytoplankton biomass by physical, chemical and biological mechanisms. Biofilters and synthetic filters in combination improve removal efficiency. Application of macroscale biofilters prior to potable water treatment works benefits the ecosystem. Plant properties, biofilter size to surface water ratio, and retention time must be considered to maximise the benefits of biofiltration processes.