Aplicação de sistemas inteligentes à optimização de um sistema de tratamento de água

Um dos principais problemas que estação de Tratamento de Água do Monte Novo tem vindo a apresentar é o aparecimento de teores em manganês na água tratada, que por vezes ultrapassam o valor paramétrico estabelecido no Decreto-Lei 306/07, 27 de Agosto (50 g dm-3). Este trabalho permitiu relacionar resultados de várias determinações analíticas efectuadas no laboratório da empresa Águas do Centro Alentejo e, através deles construir modelos fundamentados em técnicas e Descoberta de Conhecimento em Base de Dados que permitiram responder ao problema identificado. Foi ainda possível estabelecer a época do ano em que é mais provável o aparecimento de teores elevados manganês na água tratada. Além disso, mostrou-se que a tomada de água desempenha um papel relevante no aparecimento deste metal na água tratada. Os modelos desenvolvidos permitiram também estabelecer as condições em que é provável o aparecimento de turvação na cisterna de água tratada. Estas estão relacionadas com o pH, o teor em manganês e o teor em ferro. Foi ainda realçada a importância da correcção do pH na fase final do processo de tratamento. Por um lado, o pH deve ser suficientemente elevado para garantir uma água incrustante e, por outro, deve ser baixo para evitar problemas de turvação na cisterna da água tratada. ABSTRACT; The present study took place in the water treatment plant of Monte Novo. This study aimed for solutions to the problem of high values of manganese concentration in the treated water, in some periods of the year. The present work reports models for manganese concentration and for turbidity using Knowledge Discovery Techniques in Data Bases.

Effects of substrate type on plant growth and nitrogen and nitrate concentration in spinach

Abstract The effects of three commercial substrates (a mixture of forest residues, composted grape husks, and white peat, black peat and coir) on plant growth and nitrogen (N) and nitrate (NO3) concentration and content were evaluated in spinach (Spinacia oleracea L. cv. Tapir). Spinach seedlings were transplanted at 45 days after emergence into Styrofoam boxes filled with the substrates and were grown during winter and early spring in an unheated greenhouse with no supplemental lighting. Each planting box was irrigated daily by drip and fertilized with a complete nutrient solution. The NO3 content of the drainage water was lower in coir than in the other substrates. However, shoot NO3 concentration was not affected by substrate type, while yield and total shoot N and NO3 content were greater when plants were grown in peat than in the mixed substrate or the coir. Leaf chlorophyll meter readings provided a good indication of the amount of N in the plants and increased linearly with total shoot N. Keywords Spinacia oleracea; chlorophyll meter; coir; peat; soilless culture systems

Effects of substrate type on plant growth and nitrogen and nitrate concentration in spinach.

The effects of three commercial substrates (a mixture of forest residues, composted grape husks, and white peat, black peat and coir) on plant growth and nitrogen (N) and nitrate (NO3) concentration and content were evaluated in spinach (Spinacia oleracea L. cv. Tapir). Spinach seedlings were transplanted at 45 days after emergence into Styrofoam boxes filled with the substrates and were grown during winter and early spring in an unheated greenhouse with no supplemental lighting. Each planting box was irrigated daily by drip and fertilized with a complete nutrient solution. The NO3 content of the drainage water was lower in coir than in the other substrates. However, shoot NO3 concentration was not affected by substrate type, while yield and total shoot N and NO3 content were greater when plants were grown in peat than in the mixed substrate or the coir. Leaf chlorophyll meter readings provided a good indication of the amount of N in the plants and increased linearly with total shoot N.