Multi Perception Analysis of Medan City Residents Against the River Environment

Deli Medan River is one of the rivers used as a mode of transportation in the 1980s. The shift in water transportation to land causes the Deli Medan River not to get attention and tend to be ignored. This study aims to describe the perception of the people of Medan City on the Deli River Medan while at the same time looking for a correlation between each variable. This study involved 365 respondents divided from various urban villages in the Medan City area (136 men and 232 girls). The selected respondents are aged 9-60 years with a vulnerable elementary school to a college education. Spearman correlation analysis is used to see the relationship between variables. The results of the study inform that there is no relationship between pollution and siltation that occurs in the Deli River Medan, different results are shown between the changing of river transportation modes to land caused by river silting, the level of education and awareness in disposing of waste, as well as pollution that occurs and industries that dispose of waste. Wastewater in the Medan Deli River body (Sig. <0.05). Furthermore, the Deli Medan River has been polluting by waste and wastewater.

Optimization of Waste Management at the Purwosari Material Recovery Facility (MRF) Mijen District, Semarang City

Semarang City is working on constructing a Material Recovery Facility (MRF) in various urban villages to reduce the waste that enters the Jatibarang Landfill. However, the construction of MRF is not optimal. MRF Purwosari still functions as a container without waste processing. By projecting waste generation for the next ten years, the results of optimization planning are processing waste into RDF, redesigning MRF covering an area of 1,571 m2 with an investment cost of IDR 1,602,837,997 and an operational cost of IDR 307,741/ton/day. The NPV value was Rp.4,836,965, EIRR 12%, and BCR value of 1.81.

Household Solid Waste Management Strategy in Danau Teluk Sub-District, Jambi City

Danau Teluk Sub-District is one of the sub-districts in Jambi City. The waste production produced by Danau Teluk Sub-District based on DLH Jambi City data in 2020 reached 8,793.99 kg/day with a population of 12,563 people. In Danau Teluk Sub-District, the production of managed waste reached 71.05% and unmanaged waste reached 28.95%. Compared to other sub-districts, the percentage of managed waste is the lowest and the percentage of unmanaged waste is the highest. This research is conducted on influencing factors using distribution frequency and multiple linear regression, community and government involvement using distribution frequency and chi-square, and determining strategic priorities in household solid waste management using SWOT. Based on the results of the study, there are two factors that influence the management of household solid waste, namely behaviour and knowledge of local regulations, there are two factors that relate to the management of household solid waste, namely implementation and supervision, then the strategic are to carry out waste reduction starting from the source by reducing the use of goods that produce waste and providing data on waste management that is easily accessible to the public such as through social media, websites, television advertisements, bulletin boards, etc.

Utilization of Spent Nickel Catalyst as Raw Material for Ni-Rich Cathode Material

Spent nickel catalyst will be harmful to the environment if it is not processed or used properly. In fact, this waste still has a high nickel content. The treatment of spent nickel catalysts has been widely reported, but limited to nickel extraction. Since the lithium-ion batteries demand is continued to increase, then nickel is the most sought-after metal. Consequently, nickel from spent nickel catalysts could be developed as secondary source for lithium-ion battery cathode. This study aims to utilize spent nickel catalysts into more valuable materials. Nickel that has been extracted and mixed with Mn and Co has been used as raw material for nickel-rich cathode, namely NMC. Nickel extraction and NMC synthesis were using the acid leaching method followed by co-precipitation[WI1] [SSN2] . Based on the functional test performed in this work, nickel from spent nickel catalyst can be applied to Li-ion batteries. The sintering temperature that gives good characteristics and electrochemistry was found 820oC. The galvanostatic charge-discharge test gave specific capacity results for NMC of 110.4 mAh/g. The cycle test showed that NMC synthesized from spent nickel catalyst can be carried out up to 50 cycles with a capacity retention of 87.18%.

Water Quality Index Analysis for Water Drinking and Irrigation in the Sumowono Groundwater Basin

The Sumowono Groundwater Basin is a cross-district basin located in Central Java Province, between Temanggung Regency, Kendal Regency, and Semarang Regency. The people in this area obtain fresh water from either dug wells or springs. The purpose of this research is to determine the feasibility of groundwater for drinking water and irrigation purposes. The method used was hydrogeological mapping and physical and chemical analysis of 10 groundwater samples. The samples were subjected to empirical testing of the Groundwater Quality Index to determine the feasibility of drinking water and irrigation using Sodium Adsorption Ratio (SAR) analysis and Wilcox diagram. The results showed that all samples physically have tasteless and odorous properties. For the chemical properties produced in the ten samples, the pH value ranges from about 6.85 - 7.27. The electrical conductivity is between 71.6 - 511 µS/cm. Total Dissolved Solids values are between 45.82 and 327.04 mg/L, with total hardness values ranging from 10 to 170 mg/L. From the results of the SAR analysis, it is found that the groundwater classes were included in S1C1 and S1C2, so that groundwater has low alkaline in both sodium and salinity, respectively. Thus, groundwater is considered suitable for consumption and irrigation purposes,

Forecasting Greenhouse Gas Emissions from Heavy Vehicles: A Case study of Semarang City

In Indonesia, transportation sector, specifically road transport consumed most energy compared to other sectors. Eventually, the energy consumption will increase due to the growth of vehicle number that also escalate emission. Vehicle emissions had been recognized as a significant contributor to atmospheric greenhouse gas (GHG) pollution. Heavy-duty vehicles are considered as main sources of vehicular emissions in most cities. Therefore, it is crucial to take into account heavy-duty vehicle emission projections in order to support policymakers to identify vehicle emissions and develop pollution control strategies. The aim of this study is to forecast heavy-duty vehicle population, vehicle kilometers travelled (VKT), fuel consumption, and heavy-duty vehicle emissions using data of Semarang City to illustrate greenhouse gas emission of big cities in Indonesia. Business as Usual (BAU) and The Intergovernmental Panel on Climate Change (IPCC) method were incorporated to determine vehicle emission projection. Heavy-duty vehicle emissions increase from 2021 to 2030 by 12.317 to 22.865 Gg CO2/year with amount trucks and buses emissions of 21.981,5 Gg CO2/year and 884,2 Gg CO2/year, respectively.

Home Biogas Production using Homemade Bio-activator with Chicken Manure

The previous experiment was obtained that homemade activator is the best activator to produce biogas by using food waste consist of vegetable, fruit and rice waste. The current research is carried out by adding chicken manure as a co-activator. Chicken manure content rich in nitrogen can be significantly enhance biogas production. This study is expected to increase the biogas production. There are two processes conducted at the laboratory scale, batch and semi-continuous process. The batch process aim to activate bacteria. The ratio set at food waste/chicken manure, 2 : 1 of digester #1, 3 : 1 of digester #2, 4 : 1 of digester #3 and digester control using food waste only. Stage two aims to produce biogas by adding food waste for 6 days periodically. The ratio is set at food waste/water, 1 : 2. The highest biogas yielded is digester 2 with a cumulative volume biogas 120.77 liters consist of 71.01% CH4, 26% CO2, 2.9% O2 and 0.088% H2S. The potential of methane gas produced is 0.87 kWh and methane volume per TS and VS at around 18.72 L/kg and 34.68 L/kg, respectively.

Solar-Powered Electrocoagulation System for Tofu Wastewater Treatment and its Characteristic

This study aims to investigate the ability of solar-powered electrocoagulation for tofu wastewater, especially for reducing COD and TSS. This feasibility was compared with conventional electrocoagulation using electricity from the state electricity company. The study was conducted on a laboratory scale using a batch reactor electrocoagulation and aluminium electrode. The types of electrolytes used are sodium chloride and potassium chloride. The contact time is 0, 2, 4, 6, and 8 hours. The results showed that removal of COD and TSS in tofu wastewater increases with a longer electrolysis time. During two hours of electrolysis time, the removal of COD and TSS were 25 and 53.85%, respectively. This process yielded the highest COD and TSS removal of 75 and 76.9%, respectively, at 6 hours. Pseudo-second order kinetics about COD removal, both in conventional and solar panel systems, is concluded. By adding NaCl electrolytes, the conductivity of wastewater was increased, and then the removal of COD and TSS was also increased. At the end of the electrolysis time (5 hours), the pH of wastewater was neutral. The results of sludge characterization using FTIR showed the presence of hydroxyl groups, amide compound, and aromatic compound. The process of using solar panels gives results slightly different from conventional electricity, but has advantages in terms of lower operating costs and environmental friendly.

Re-layout of Temporary Storage Area for Toxic and Hazardous Waste using 5S (Seiri, Seiton, Seiso, Seiketsu, Sitsuke)

One of the industries that produces toxic and hazardous waste is rubber industry. This study was conducted in PT. Famili Raya. The problem was toxic and hazardous waste placed in an irregular placement and no follow the government regulations for storing and managing. This aims of this study were to redesign temporary storage area for hazardous waste based on 5S (Seiri, Seiton, Seiso, Seiketsu, Shitsuke) and the regulation, Minister of Environment and Forestry No. 12/2020. The object of this study was temporary storage area for toxic and hazardous waste in PT. Famili Raya. The data used were current condition, actual dimensions of temporary storage area, dimensions of waste, input and output data, and dimensions of a forklift. The results obtained were the proposed layout using the 5S approach could be used to redesign the storage layout in the temporary storage area. Space utility could be reduced by 32,67%. The decrease in space utility did not reduce the maximum storage capacity for used batteries, used tubular lamp, used oil waste, and turpentine oil waste.