Numerical Modeling Applied to Leachate Generation using Hydrus – Case Study: Seropédica, Rio de Janeiro, Brazil

ABSTRACT Improper design and management of the cover layer of a sanitary landfill has been proven to produce harmful environmental impacts on the environment. One alternative at hand is to develop scenarios based on simulation of physical and computational models to represent the expected field water balance of a landfill coverage layer. This paper investigates the design of a sanitary landfill final cover in the municipality of Seropédica, which is located at the state of Rio de Janeiro - Brazil. More specifically, the compact soil coverage, which is widely used for landfill final cover of municipal solid waste, is evaluated in contrast to vegetation cover by grass, vegetation cover by brachiaria and capillary barrier. To accomplish such task, hydrometeorological forcing conditions, namely daily rainfall and temperature, were retrieved from the Anchieta weather station, which is situated nearby the study area. The Hydrus 1D and 2/3 D computational codes were employed to develop a set of scenarios to follow the contamination plume evolution within the landfill along the time frame of 20 years with some degree of reliability. It should be noted that the performed evaluation indicates the possibility to control the leachate release and consequently to avoid contaminating the environment, notably to prevent soil and water resources pollution. Vegetation cover by grass and brachiaria showed important control mechanisms with respect to the movement of the contaminant plume. In addition, it should be noticed that the best results for the landfill final cover were achieved for the capillary barrier, while poor performance results were obtained for the commonly employed compact soil.

The settlement Cernavoda III culture on the site Bubanj near Nis

Archaeological investigations carried out between 2008 and 2010 in the east sector of site Bubanj near Nis (Plan 1; Figs. 1-3) confirmed the existence of horizon of the Cernavoda III culture. In features 22, 23 and 31, which are the remains of settlement buildings, have been found archaeological material mostly pottery vessels, which according to style of decoration, technological and morphological characteristics could be ascribed to the initial period of late Eneolithic. Also, the dwelling structures of Krivodol-Salcu?a-Bubanj cultural complex have been recorded in the layer of brown soil with the remains of above mentioned Cernavoda III buildings. In the vertical stratigraphy of trench I (Fig. 4) the mentioned layer was encountered immediately under the layer of whitish/gray ashy soil and thin layer of compact soil of gray color (Fig. 5), which date from the advanced phases of the late Eneolithic and above the early Eneolithic layers. The settlement features recorded during 2009 excavations are parts of the structures from the settlement of Cernavoda III culture (Fig. 6; T. I-III). Feature 22 is section of devastated probably aboveground building, feature 23 is shallow pit and feature 31 is most probably the rubbish pit. Very similar stratigraphy of the site had been recorded by investigations of M. Garasanin in 1954. In the layer of brown soil, the material of Cernavoda III culture was discovered in level III, and in level IV both Cernavoda III and the material of the earlier Krivodol-Salcu?a-Bubanj cultural complex was recorded. These building horizons are at different depths within approximately same area of the trench and have been identified on the basis of considerable amount of daub and stone, two floor levels, wooden building material and fragmented pottery vessels (T. IV-VI). Despite the lack of technical field documentation remains of one above ground structure could be identified at level III according to descriptions from field journal from 1954. Certain finds from level IV indicate that remains of some floors from this level could perhaps be associated with structure from the settlement of Cernavoda III culture. Insufficient investigations and small quantity of published material from the settlements of this period and mostly singlelayered sites with poorly preserved cultural layer resulted in the fact that in certain areas there are only indications for the settlements. The position of the site at Bubanj suggests the importance of controlling the zone of confluence of the Nisava River and the South Morava River where from the roads branched toward north, south, west and east along the river valleys. The investigations of prehistoric settlements carried out so far at the site Bubanj confirm that areas of the Nisava and South Morava valley had been included in the cultural complex Cernavoda III- Boleraz, which covers rather large part of southeast and central Europe.

Cocooning Behaviour of Overwintering Codling Moth Larvae

Codling moth larvae seeking overwintering sites usually spin up during hours of darkness on the trunks and larger branches of apple trees rather than in the soil or in debris under the trees. The number on the ground depends on the suitability for cocooning sites of the bark on the tree and on the amount and type of debris on the ground. Gould and Geissler (1941) found that larvae did not spin up in bare and compact soil and Steiner (1929) observed that most larvae returned to the tree to spin cocoons when there was little or no litter beneath the trees. Baker (1944) reported eight to nine per cent spun up on the ground beneath unscraped trees, and 18 per cent where the loose bark scales were removed. Others (Headlee (1929). Worthley (1932), Gnadinger et al. (1940), Woodside (1941), and Stultz (1946), found that under natural conditions from 0 to 14 per cent spun up in the soil, in the cover crop, or in the debris on the ground.