ABSTRACT Studies show that aquatic plants are an efficient alternative to minimize the harmful effects of wastewater. Two species of aquatic macrophytes (Pistia stratiotes and Eichhornia crassipes) were chosen to evaluate the temperature effect on the performance of these macrophytes species in a post-treatment system of swine wastewater. The experiment was carried out in the municipality of Toledo, Paraná State, Brazil. For the experimental system, 24 concrete tanks with 80 L capacity were used, each measuring approximately 1.5 m in length, 0.25 m in width and 0.16 m deep. Wastewater characteristics and variables hydrogen potential (pH), electrical conductivity (EC), and dissolved oxygen (DO) were measured weekly. After, we analyzed the aquatic macrophytes and centesimal composition. The use of aquatic macrophytes was efficient for final swine wastewater polishing. Nitrogen removal showed higher efficiency in the summer period for both species studied. The abiotic variables (pH and EC) presented better results during the winter for both species evaluated. Air and wastewater low temperatures did not influence these variables. Dissolved oxygen presented better results in the summer period for E. crassipes species. There was a significant increase in N and P contents in the plant tissue. This fact proves that the use of aquatic macrophytes is an interesting alternative for swine wastewater treatment.
ABSTRACT The objective of this study was to calculate simple allometric equations in order to estimate above and below ground dry biomass from Leucaena leucocephala individuals. Results indicated that biomass components show the following pattern: stem > branches > roots > leaves. Independently from individual size, 24 % of total sampled dry biomass was located below-ground, and 76 % above-ground. Log transformed linear equations using CBH (circumference at breast height) as independent variable was statistically significant (P<0.05) to estimate leucaena total dry biomass.
RESUMO Ecossistemas florestais são responsáveis pelo maior acúmulo de carbono da biosfera terrestre. A quantificação da biomassa para espécies florestais vem contribuir com informações diretas sobre seu potencial para o seqüestro do carbono atmosférico. O ensaio objetivou ajustar equações que permitam estimar a biomassa aérea e subterrânea de Leucaena Leucocephala (Lam.) De Wit por meio do método direto. Para estimar a potencialidade da Leucaena leucocephala na fixação do carbono, foi utilizado o fator de conversão 0,5. Do total da biomassa e do carbono em indivíduos de Leucaena leucocephala, 24% correspondem ao sistema radicular e 76% correspondem ao sistema aéreo. De forma geral, a biomassa total apresentou a distribuição: fuste > galhos vivos > raízes > folhas. O modelo linear com transformação logarítmica utilizando CAP variável independente foi estatisticamente significativa para estimar biomassa seca total.