Engineering Headway Vol. 19

Abstract: The pulp and paper industry, a major consumer of freshwater, generates wastewater rich in contaminants, including ammonia, chemical oxygen demand (COD), total suspended solids (TSS), and organic materials. Effective treatment of this liquid pulp waste is crucial to prevent environmental pollution. This study investigated the microbiological treatment of primary pulp industry liquid waste using the petrophilic bacterium Brevundimonas diminuta. The research assessed the bacterium's capacity to degrade ammonia, COD, and TSS under varying aeration rates (0 L/min, 2.25 L/min, and 4.5 L/min) and observation durations (4, 6, and 8 hours). Results revealed that the optimal reduction in ammonia levels, reaching 64%, occurred within 6-8 hours with 4.5 L/min aeration. Likewise, COD reduction peaked at 90% under 4.5 L/min aeration over 8 hours, while TSS degradation reached 76% under 4.5 L/min aeration within 6 hours. These findings demonstrate the ability of petrophilic bacteria to effectively mitigate liquid pulp and paper waste under specific processing conditions, emphasizing the significance of aeration rate and duration in this biodegradation process

Abstract: Constructed wetlands are intentionally created systems designed to emphasize specific characteristics of wetland ecosystems to improve landscape, retain stormwater, and enhance its quality. The application of this system has been widely used in several countries as this system is low-cost and sustainable. The treatment performance of constructed wetlands critically relies on the optimal operating parameters, including hydraulic retention time. This prompted the implementation of this study to analyze the effectiveness of retention time variation on constructed wetland performance for domestic wastewater treatment plant. The design of the constructed wetland in this research uses Free Water Surface (FWS) or Surface Flow (SF) system using sand, gravel, and water hyacinth. Domestic wastewater from a local restaurant was used as the sample for this research. The initial kitchen wastewater concentration from the restaurant does not meet the effluent standard by the Ministry of Environment and Forestry Regulation No.68/2016. Data analysis shows a significant decrease in all pollutant parameters after 24 hours of retention time. The initial condition of BOD 1931 mg/L has been reduced to 25.12 mg/L with 98.69% efficiency. The initial condition of TSS 1200 mg/L has been reduced to 29 mg/L with 97.58% efficiency. The oil and grease concentration of 227.5 mg/L has been reduced to 1 mg/L with 99.5% efficiency. At the same time, the initial condition of COD 1356 mg/L has been reduced to 73.29 mg/L with 94.6% efficiency.

Abstract: One kind of heavy metal that comes from industrial waste is Cr (VI), which is obtained from steel, textile, tanning, photography, dyes, explosives, matches, and fuel mobilization waste. Cr (VI) is a carcinogen and extremely hazardous to both people and animals. In Indonesia, bentonite is a raw material that is abundantly available. This study aims to investigate the effects of varying adsorbent doses on the properties, % removal, isotherms, and kinetics of adsorption of Cr (VI) from aqueous solution. Adsorbent doses ranged from 10 g/L to 30 g/L for 0–80-minute contact periods. morphological analysis of bentonite using a scanning electron microscope (SEM). Features of bentonite were tiny lumps of varying sizes and the absence of pores. 96.5% is the optimal elimination of Cr (VI). The morphological analysis of bentonite using a scanning electron microscope (SEM). Features of bentonite were tiny lumps of varying sizes and the absence of pores. When using a dose of 20 g/L and a 60-minute duration, the maximum elimination of Cr (VI) is 96.5%. Isotherms follow Langmuir and kinetics fit to first order. These findings demonstrate that bentonite is a valuable material for future development and is effective at removing Cr (VI) from aqueous solutions.

Abstract: This study focuses experimentally on the bearing capacity of group pile foundations used in the Palembang Health Polytechnic Dental Nursing Lecture Building, considering that this type of foundation is able to support a large enough load. To determine the efficiency of the bearing capacity of pile foundations, calculations were made based on N-SPT data using the Vesic 1977 method and exsisting. The study was conducted at the PC-9A point at the Palembang Health Polytechnic Dental Nursing Building using variations in diameter Ø30, Ø40, Ø50, Ø60, 35 x 35, 40 x 40, and 45 x 45 at depths of 11, 12, 13, 14, 15, 16 m, with a fixed concrete quality of K-500. The results of the calculation of the bearing capacity of the group pile found ation, on PC-9A in Vesic 1977 amounted to 2761.576 kN and used vesic 1977 amounted to 2763.28 kN with a difference of 23%. The largest foundation bearing capacity is located at 40 x 40 dimensions with a bearing capacity of 3698.97 kN, while the smallest foundation bearing capacity is located at 30 diameters with a bearing capacity of 2784.84 kN. The results of the calculation of variations on the efficient PC-9A are Ø30 depth 12 m with a volume of 7.6302 m, Ø30 depth 14 m with a volume of 3.9564 m3, Ø40 depth 12 m with a volume of 7.6302 m3, Ø40 depth 13 m with a volume of 3.6738 m3, 35 x 35 depth 13 m with a volume of 6.370 m3, 40 x 40 depth 13 m with a volume of 8.30 m3 with a bearing capacity of 3698.97 kN.

Abstract: Nowadays the construction of palm oil industry mills is advancing rapidly and the next one is Refined Palm Oil (RPO). Refined Palm Oil (RPO) is one of the derivatives of palm oil processing. One option to use structures in the construction of palm oil mills is to use concrete. Plant parts that have concrete components often suffer damage, cracks and reduced concrete strength.This study is intended to examine the mechanical properties of concrete including compressive strength, flexural strength and porosity in concrete in the RPO environment, examining changes in the weight of coarse and fine aggregates immersed in RPO. This study used concrete experiments in RPO baths with 3 combinations, 54 samples and 2 types of concrete plan life, then analyzed in the laboratory. The parameters measured are changes in aggregate weight, porosity, bending strength and compressive strength of concrete. The results showed that the higher the percentage of RPO immersed in concrete, the lower the compressive strength, bending strength and porosity of the concrete. Fine aggregate undergoes weight change when immersed in RPO for 28 and 56 days, while coarse aggregate undergoes no weight change

Abstract: Throughout the architectural history of Indonesia, particularly in Palembang, Dutch influence has left a notable mark on several buildings in specific regions. The adaptation of Dutch Colonial Architecture to the local climatic conditions in the Talang Semut area of Palembang has revealed a rich diversity in architectural styles and functions. This adaptation process bears relevance not only in historical contexts but also in contemporary and future design practices. This research employs a descriptive analysis methodology to investigate the process of adapting Dutch Colonial architecture to the tropical climate of Palembang. The findings underscore the significant impact of this adaptation, resulting in buildings that harmoniously integrate with their local environment, reducing reliance on artificial air conditioning systems. Dutch colonial architecture's climatological solutions have stood the test of time, offering a sustainable approach to architectural design that remains relevant today and holds promise for the future.

Abstract: The earthquake caused by the Garsela Fault significantly damaged the infrastructure and home of residents around Pasirwangi District. This fault is in Garut Regency, West Java and is one of the primary sources of earthquakes in Garut. This study aims to calculate rate of surface deformation and interpret its causes by analyzing InSAR data from 2017 to 2021. LiCSBAS, a Python-based time-series deformation analysis program, processed InSAR data to determine fault movement attributes and sources. Geological mapping, analysis of fault kinematics and dynamics determine the characteristics and fault movement. The results of time series analysis show that the rate of surface deformation in the Pasirwangi and its surrounding areas ranges from -45 mm/year to 35 mm/year. The movement mechanism of normal and right-normal slip faults causes the dominant surface subsidence. The difference in maximum ground movement acceleration between the north and south areas is caused by force moments which distributed at building points, affected by the differences in building density in the research area.