Yes / Water scarcity is a huge problem in Africa, and hence rainwater becomes a crucial water source for fulfilling basic human needs. However, less attention has been given by African countries to the effectiveness of common rainwater treatments to ensure the population's health. This study investigates the impact of different household treatment techniques (HHTTs), i.e. treatments by chlorine, boiling, alum, and a combination of alum and chlorine, on its storage system using a case study at the Ikorodu area of Lagos state, which is a rural area in Nigeria. The first-flush quality has been particularly studied here, where the microbial reduction through its practice has been examined from five different roofs. One of the investigated roofs was from a residential building, and four were constructed for the purpose of this study. In this study, the physical parameters (i.e. total suspended solids and turbidity) and the microbial parameters (i.e. total coliform and Escherichia coli) of the collected rainwater have been investigated. From the results, it has been observed that: (1) the water quality at the free phase zone is better than that at the tank's bottom; (2) the combination of chlorine and alum gives the best rainwater quality after comparing the application of different HHTTs; and (3) a reduction of about 40% from the original contaminant load occurs in every 1 mm diversion. / Hidden Histories of Environmental Science Grant Project (at Seed-grant Stage), funded by the Natural Environment Research Council (NERC) and Arts and Humanities Research Council (AHRC), part of UK Research and Innovation (UKRI)

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Yes / This study investigated the impact of sedimentation on rainwater storage system using a case study at the Ikorodu area of Lagos state, a rural area in Nigeria. In this investigation, the proportions of Escherichia coli (E. coli) that were settleable (due to sedimentation) and those that were at the free phase have been studied. Water samples were collected from different depths in the inspected rainwater storage tank at two different periods (i.e. rainy and dry periods) for 20 days. The samples collected from these periods have been analysed for physical and microbial measures before passing it through the serial filters with pore sizes of 500 μm, 100 μm, 10 μm and 1.5 μm to measure the retained particle mass. From the results, it was observed that: (1) the water quality at the free-phase zone was better than that at the tank’s bottom; (2) the settleable bacteria rapidly sinked to bottom; (3) the correlation of turbidity, E. coli and total suspended solids (TSS) for all the rain events showed a relatively high Pearson’s coefficient of 0.9 to one another; and (4) over 70% of settling TSS occurred within first 36 hours. Finally, it has been found that the physical sedimentation process can significantly reduce the microbial measures.

Made available in DSpace on 2016-12-23T14:04:28Z (GMT). No. of bitstreams: 1 Thanira Thammy Bastos Vilches.pdf: 1736718 bytes, checksum: 0125ce265ba8a796bb53677bd39e82a4 (MD5) Previous issue date: 2013-03-11 / Suspended solids transport excess, caused by erosion, may limit water use and cause rivers siltation. Suspended solids concentration may be assessed by remote sensing because the reflectance of the scenes, in the visible and infrared ranges, is positively influenced. This work aims at the understanding of the variability of suspended sediments concentrations in a Doce river stretch located in Espírito Santo state, Brazil, through spectral analysis of satellite images data and analysis of field measurements results. There were analyzed suspended solids concentrations for samples collected in Regência and Colatina Doce river sections and images captured by LANDSAT 5 TM satellite. To obtain reflectance values, the following operations were performed: geometric correction, conversion of DN values to apparent FRB values, atmospheric correction, using the 6S model (FRB surface), and transformation of NCs values.The results showed that, for the images corrected from atmospheric effects, the values of the ND curve related to the apparent FRB are higher than the values of the surface s FRB curve in the visible region, due to the electromagnetic radiation scattering phenomenon. In the near-infrared regions, the reverse was observed, because of the absorption of electromagnetic radiation by the atmosphere. It was observed positive correlation between reflectance and suspended solids concentration, despite the difficulties in obtaining data from same satellite images and field sample collection dates. For Regência data, the best correlation was obtained for band 1, located in the visible range of the surface s FRB curve, suggesting less suspended sediment transport. For Colatina, the best correlation occurred for band 4, located in the near-infrared range of the same surface s FRB curve, indicating greater sediment transport in this part of the Doce river during the sampling dates. It was concluded that the surface reflectance best represents the water spectral curve and that the correlated data showed the following pattern: smaller reflectance corresponds to lower water suspended solids concentration / O transporte de sólidos em suspensão, causado por erosão, é um dos problemas que limitam o uso da água, podendo causar assoreamento nos rios. A concentração de sólidos suspensos pode ser avaliada através do sensoriamento remoto, pois a reflectância da cena, na faixa do visível e do infravermelho, é positivamente influenciada. Desta forma, este trabalho visa o conhecimento da variabilidade das concentrações de sedimentos em suspensão no trecho do rio Doce localizada no ES, através de análises de dados espectrais contidos nas imagens orbitais e de resultados de medições em campo. Para tanto, foram avaliados dados concentrações de sólidos suspensos em amostras coletadas em Regência e Colatina, e imagens TM do satélite LANDSAT 5. Para obtenção dos valores de reflectância, foram realizadas as seguintes operações: correção geométrica, conversão dos NDs para valores de FRB aparente, correção atmosférica com uso do modelo 6S (FRB superfície), e transformação de NCs em valores de reflectância. Os resultados mostraram que nas imagens corrigidas dos efeitos atmosféricos, os valores da curva de ND referentes aos FRBs aparentes são superiores aos valores da curva FRB de superfície na região do visível, devido ao fenômeno de espalhamento da radiação eletromagnética. Nas regiões do infravermelho próximo, ocorreu o inverso, uma vez que há absorção da radiação eletromagnética pela atmosfera. Quanto aos sólidos suspensos, foram encontradas correlações positivas entre a reflectância e a concentração dos sólidos suspensos, apesar das dificuldades de obtenção de dados concomitantes das datas de imagens orbitais com datas da coleta de campo. Para os dados de Regência, a melhor correlação ocorreu para banda 1, que se localiza na faixa do visível, da curva dos FRB de superfície, sugerindo menor transporte de sedimentos suspensos. Para Colatina, ocorreu para banda 4, que se encontra na faixa do infravermelho próximo, também para curva dos FRB de superfície, sugerindo maior transporte de sedimentos nesse trecho do rio Doce, para as datas de amostragem. Conclui-se que a reflectância que melhor representa a curva espectral da água é de superfície e os dados correlacionados seguiram o padrão de quanto menores as reflectâncias, menores as concentrações de sólidos suspensos na água

Imagens adquiridas por sensores orbitais possibilitam observações da Terra e auxiliam estudos de grande áreas. Este trabalho utilizou imagens orbitais para analisar os componentes que modificam as características óticas da água na Lagoa dos Patos, localizada no sul do Brasil. A partir de imagens multiespectrais dos sensores MODIS/Terra e OLI/Landsat-8, foi possível avaliar a variação espaço-temporal de sólidos em suspensão (SS) e estimar alguns parâmetros de qualidade da água na Lagoa dos Patos. Na primeira etapa desse trabalho, o padrão anual e espacial de SS na laguna foi determinado com base em uma série de 15 anos do produto MOD09Q1 (reflectância na faixa do vermelho do sensor MODIS). Foi observado que a reflectância possui um padrão sazonal com aumento do outono até o final da primavera, e que no corpo lagunar e no estuário a reflectância varia ao longo do ano. Interpretações da variação da reflectância, relacionadas a descarga fluvial e a ação dos ventos, foram apresentadas. Na segunda etapa desse trabalho, o modelo linear de mistura espectral (MLME) foi aplicado em uma imagem do sensor OLI para separar águas espectralmente distintas do estuário da Lagoa dos Patos. A partir das imagens frações, geradas pelo MLME, e das bandas do sensor OLI e TIRS modelos empíricos foram desenvolvidos para estimar alguns parâmetros de qualidade da água. Os modelos obtidos foram capazes de estimar a concentração de clorofila-a (R2 = 0,82) e de sólidos em suspensão (R2 = 0,62), a turbidez (R2 = 0,67) e a profundidade do disco Secchi (R2 = 0,64). Conclui-se que o MLME e os dados do satélite Landsat-8 apresentam grande potencial para estimativa de parâmetros da água por imagens orbitais. / Images acquired by orbital sensors enable observations of the Earth and assist studies of large areas. This work used orbital images to analyze the components that modify the optical characteristics of the water of Lagoa dos Patos, located in the southern region of Brazil. By using multispectral images from MODIS/Terra and OLI/Landsat-8 sensors it was possible to evaluate the spatio-temporal variation of suspended solids (SS) and estimate some parameters of water quality. In the first stage of this work, the annual and spatial pattern of SS were estimated based on a series of 15 years of MOD09Q1 product (reflectance in the red channel of MODIS sensor). It was observed that the reflectance has a seasonal pattern with increase in the autumn until the late spring, and that in the lagoon body and estuary the reflectance varies throughout the year. Interpretations of the spatio-temporal variation of reflectance related to river discharge and the action of the winds were presented. In second stage of this study, the Linear Spectral Mixing Model (LSMM) was applied to an image of the OLI sensor to separate spectrally distinct waters of Lagoa dos Patos estuary. From the fraction images generated by LSMM and the bands of OLI and TIRS sensors, empirical models were developed to estimate some parameters of water quality. The obtained models were able to estimate the concentration of chlorophyll (R2 = 81,56) and the suspended solids (R2 = 61,57), turbidity (R2= 67,14) and Secchi disk depth (R2 = 64,29). Combination of LSMM and the Landsat- 8 satellite have shown great potential for water parameters estimation from orbital images.

Vegetated roof technologies are increasingly being adopted as treatment measures to mitigate the effects of urban stormwater. A mass balance approach was used to assess the wet weather performance of a vegetated roof on the top of city hall in Waterloo, Ontario. Vegetated and control roof sections were instrumented to measure precipitation inputs, storage and outflow for 18 storm events from June to October, 2006. Concentrations of suspended solids (SS), total phosphorus (TP), soluble reactive phosphorus (SRP), copper (Cu), zinc (Zn), chromium (Cr) and cadmium (Cd) in precipitation and roof (vegetated and control) runoff were measured. A total of 155.6 mm of rain fell during the study period. The vegetated roof retained 64.5 mm (41.5%) of the total rainfall while the control roof retained ~ 5.1 mm (3.3 %). For individual rain events, the vegetated roof retained an average of 3.5 mm (47.6 %) while the control roof retained ~ 0.3 mm (4.7 %). Water retention varied with storm size, season and was influenced by wetting history. The vegetated roof retained 80.6 % of precipitation for light storm events (≤ 3.5 mm) and 34.9 % for large storm events (> 3.5 mm). The control roof retained 7.6 % light storm events and 3.7 % for large storm events. Water quality from the vegetated roof did not show significant improvement as only Zn concentrations in runoff from the vegetated roof were significantly lower than that measured in runoff from the control roof. Concentrations of SS, Cu, Cr and Cd in vegetated roof runoff were relative to concentrations in rainfall and control roof runoff and TP and SRP concentrations were significantly higher than that in rainfall or control roof runoff. Results gained from this study may assist people in planning and stormwater management by providing insight into the monitoring, development and application of new stormwater controls.

Vegetated roof technologies are increasingly being adopted as treatment measures to mitigate the effects of urban stormwater. A mass balance approach was used to assess the wet weather performance of a vegetated roof on the top of city hall in Waterloo, Ontario. Vegetated and control roof sections were instrumented to measure precipitation inputs, storage and outflow for 18 storm events from June to October, 2006. Concentrations of suspended solids (SS), total phosphorus (TP), soluble reactive phosphorus (SRP), copper (Cu), zinc (Zn), chromium (Cr) and cadmium (Cd) in precipitation and roof (vegetated and control) runoff were measured. A total of 155.6 mm of rain fell during the study period. The vegetated roof retained 64.5 mm (41.5%) of the total rainfall while the control roof retained ~ 5.1 mm (3.3 %). For individual rain events, the vegetated roof retained an average of 3.5 mm (47.6 %) while the control roof retained ~ 0.3 mm (4.7 %). Water retention varied with storm size, season and was influenced by wetting history. The vegetated roof retained 80.6 % of precipitation for light storm events (≤ 3.5 mm) and 34.9 % for large storm events (> 3.5 mm). The control roof retained 7.6 % light storm events and 3.7 % for large storm events. Water quality from the vegetated roof did not show significant improvement as only Zn concentrations in runoff from the vegetated roof were significantly lower than that measured in runoff from the control roof. Concentrations of SS, Cu, Cr and Cd in vegetated roof runoff were relative to concentrations in rainfall and control roof runoff and TP and SRP concentrations were significantly higher than that in rainfall or control roof runoff. Results gained from this study may assist people in planning and stormwater management by providing insight into the monitoring, development and application of new stormwater controls.

The topic of this thesis is the impact of fish pond harvest on water quality especially on concentration of suspended solids and phosphorous. Goal of the study is to contribute to ongoing discussion about carp aquaculture's role in fresh water pollution. Sampling was carried out in five carp ponds in the Třeboňsko Protected Landscape Area. Main monitored parameters were concentration of suspended solids and total phosphorous during pond drainage and fish harvest.Results of the study confirmed very negative impact of fish harvest on water quality in recipient water.