Waste has become one of the problems that until now has not been resolved in the community. One type of waste that is abundant is organic waste in the form of leaves. Based on this fact which demands a creative and innovative way of processing waste into a powerful product. One effort made is the utilization of leaf waste as organic color pigment on white board marker ink. Pigment is obtained by reducing leaf waste to homogeneous form of carbon powder that is burning leaf garbage in low oxygen condition then done simple mixing process with other material of ink maker. The resulting ink is tested for transmittance in carbon mass variations in the range from 1 to 6 grams, the results show that the more carbon mass, the lower the intensity of the light passes. The absorption rate test shows that the carbon inks have a speed similar to the ink type on the market, which is 0.081 mm / s. When the performance test of the carbon ink on the white board shows almost the same result of black with commercial ink and can adhere well so it is suitable if applied as white board marker ink.

The seawater intrusion into the groundwater in Tanah Mas Residential North Semarang was investigated by chlorides ion levels from production wells and 3D electrical resistivity profiling. Tanah Mas residential area is a densely populated area located in the northern coastal city of Semarang. At the area, the exploitation of groundwater through production wells is quite high, that potential to produce the phenomenon of seawater intrusion. Analysis of groundwater samples from production wells was carried out as an early indication of the seawater intrusion in the study area. The profiles acquired across the study area, using a multi-electrodes acquisition system in a Wenner array configuration by electrode spacing of 10 m were used for the profiling. The results of groundwater chemical testing, there are three groundwater samples that has high levels of chloride ions. Three groundwater samples have the high levels of chloride ions that are in wells F, J and M. Apparent resistivity data of the 2D profiles over the models were collated to 3D data sets for each array studied. From 3D electrical resistivity profiling, obtained the distribution of seawater intrusion that has reached the north, east and south of Tanah Mas residential.