Search

In some areas, compacted clay liner is chosen as leachate barrier for solid waste landfill. Due to the typical shape of the landfill, the compacted clay liner will be rested both in flat and sloping ground. Since clay has characteristics of low shear strength, improvement of shear stability of compacted clay liner is required. One of the stability methods to increase the shear strength of clay is by adding another material which has higher shear stability. In this study, bentonite is used to represent clay liner while zeolite is utilized as stabilizer material. Four compositions of bentonite with 0%, 5%, 10%, 15% addition of zeolite were prepared to investigate the stability performance of the mixtures. The results indicate that the addition of zeolite into bentonite has increased the friction angle of the bentonite. However, the addition of zeolite seems to alter the hydraulic performance of bentonite. The highest permeability is demonstrated by the bentonite with 15% of zeolite. Whether the permeability increases, the hydraulic performance of all the mixtures are still met the maximum permeability allowed for landfill liner.

An alternative material that could be used as a liner, which can avert the heavy metal migration from landfill to soil, is the combination between bentonite and zeolite. This study aims to analyze the Pb2+ adsorption capacity of the liner and permeability of bentonite with the addition of zeolite in several percentages. There were four different types of composite in the experiment, such as pure bentonite (BZ0), bentonite + zeolite 2% (BZ2), bentonite + zeolite 5% (BZ5), and bentonite + zeolite 8% (BZ8). Bentonite and zeolite composite was inserted into a cylindrical reactor, which was compacted to adjust the condition of the study to be similar with existing condition in the landfill. This study was conducted until the leachate produced and lead concentration was tested using samples from the liner and leachate in the outlet. The results showed that the highest efficiency of lead reduction was obtained from BZ8 with the percentage of 95.2%, while the highest permeability coefficient was found in BZ8 with the value of 7.76 x 10−11 cm/s. The addition of zeolite has been proven to be able to reduce the lead concentration of leachate, but it increased the possibility of leakage.

An investigation on the use of landfill bioreactors was conducted to elaborate an alternative solution on the municipal solid waste management in Jatibarang Landfill, Semarang. In addition, this study is also trying to develop a prevention on leachate and greenhouse gases pollution which are potentially emits from a landfilling process. There are six landfill bioreactors that were constructed for this study, which consist of two anaerobic bioreactors (R1 and R2) and two aerobic bioreactors (R3 and R4). Leachate recirculation was applied on R1 and R2 since the leachate production began while R3 and R4 was given air injection with 2 l/min flow rate. R1 and R2 maintained its thermophilic phase longer and generated more methane gases than aerobic bioreactors. Meanwhile, both aerobic bioreactors reached the thermophilic phase on day-7, faster than the anaerobic bioreactors.

Currently, the presence of laboratories has become a difficult thing to be separated from the learning system in the university. Moreover, there are many universities that have begun to encourage their students and lecturers to do researches more frequent, for needs both of lecture activities and theses. These conditions trigger the laboratory management to improve their service quality, such as through improvement of the comfortability. From this improvement, it is expected to increase the productivity of people who are doing their activities in a laboratory. However, while the working productivity is being prioritized, there is a problem that is often forgotten, namely health and safety environment. An unhealthy working environment has the possibility to cause stress to people who are working in it. Hazard potentials that exist in a laboratory are caused by the use of reagents and research equipment. To prevent the occurrence of these hazard potentials, deep understanding of risks potential in a laboratory is needed. Based on a research at XYZ Laboratory, a risk analysis and risk assessment are needed to be done by a laboratory, which is often used by students and lecturers in a university, with the purpose of determine the severity and likelihood level of an incident happened. Furthermore, AS/NZS 4360-2004 method, which is used in this research, is also a method to determine the priority of how handle a risk and what is the best step to prevent it.

Landfilling is one of the easiest methods to be applied in the management of municipal solid waste (MSW). In its development, bioreactor landfill methods that have various advantages over conventional landfill emerge. This experiment aims to study the use of bioreactor landfills for the management of organic waste in Jatibarang Landfill, Semarang-Indonesia. There are 4 bioreactor landfills operated: 2 anaerobic bioreactors with leachate recirculation and addition of water, and 2 aerobic bioreactors. Different results are shown from these two types of bioreactor, where aerobic bioreactors reach peak temperatures (55oC each) faster even though anaerobic bioreactors reach higher temperatures (60oC and 61oC respectively). Anaerobic bioreactors reach a higher final pH value than aerobes while the accumulation of nitrogen content from an aerobic bioreactor is 2 times higher than anaerobes.