Solid waste characterization and reducing potential at Faculty of Engineering, University of Surabaya

Reducing solid waste generation is one of the green campus achievement programs at the University of Surabaya (Ubaya). It is essential to determine the quantity and composition of all faculty’s solid waste generation. The Faculty of Engineering significantly contributes to the amount of waste generation in Ubaya. Research related to the Faculty of Engineering solid waste characteristics needs to be conducted. The purposes of the study were estimating the quantity of solid waste generation and observing the composition of solid waste at the Faculty of Engineering. The method of this research was a survey of waste generation. The estimation of waste generation was taken for 12 (twelve) days during April 2018. The study results showed that the average solid waste generation faculty of engineering was to be 19.26 kg/day, and the percentage of solid waste was found to be food waste 27%, plastic 25.8%, food packaging 17.6%, Paper 9.8%, and Residue 19.8%.

A Study on Machine Learning Methods’ Application for Dye Adsorption Prediction onto Agricultural Waste Activated Carbon

The adsorption of dyes using 39 adsorbents (16 kinds of agro-wastes) were modeled using random forest (RF), decision tree (DT), and gradient boosting (GB) models based on 350 sets of adsorption experimental data. In addition, the correlation between variables and their importance was applied. After comprehensive feature selection analysis, five important variables were selected from nine variables. The RF with the highest accuracy (R2 = 0.9) was selected as the best model for prediction of adsorption capacity of agro-waste using the five selected variables. The results suggested that agro-waste characteristics (pore volume, surface area, agro-waste pH, and particle size) accounted for 50.7% contribution for adsorption efficiency. The pore volume and surface area are the most important influencing variables among the agro-waste characteristics, while the role of particle size was inconspicuous. The accurate ability of the developed models’ prediction could significantly reduce experimental screening efforts, such as predicting the dye removal efficiency of agro-waste activated carbon according to agro-waste characteristics. The relative importance of variables could provide a right direction for better treatments of dyes in the real wastewater.

The Role of Biowaste: A Multi-Objective Optimization Platform for Combined Heat, Power and Fuel

Biomass, bioenergy and negative emission technologies are inherent to the future design of energy systems. Urban clusters have a growing demand for fuel, heat and electricity, which is both a challenge and an opportunity for biomass-based technologies. Their deployment should meet demand, while minimizing environmental impact and staying cost-competitive. We develop a systematic approach for the design, evaluation and ranking of biomass-to-X production strategies under uncertain market conditions. We assemble state-of-the-art and innovative conversion technologies, based on feedstock, by-products and waste characteristics. Technical specifications, as well as economic and environmental aspects are estimated based on literature values and industry experts input. Embedded into a bi-level mixed-integer linear programming formulation, the framework identifies and assesses current and promising strategies, while establishing the most robust and resilient designs. The added value of this approach is the inclusion of sub-optimal routes which might outperform competing strategies under different market assumptions. The methodology is illustrated in the anaerobic digestion of food and green waste biomass used as a case study in the current Swiss market. By promoting a fair comparison between alternatives it highlights the benefits of energy integration and poly-generation in the energy transition, showing how biomass-based technologies can be deployed to achieve a more sustainable future.

Appropriate Technology for Municipal Solid Waste Management Based on Wastepreneurship Implementation

Piyungan landfill is the biggest landfill in the Special Region of Yogyakarta, Indonesia, which receives municipal solid waste (MSW) from two districts and a city, while its designed service time has been over and faces operational obstacles. Meanwhile, the volume of the MSW grows rapidly and exceeds the reduction rate in their sources. The difficulty in finding a new landfill area is the reason why appropriate technological alternatives in the MSW management are strongly needed. Therefore, the study aimed to evaluate the social and economic aspects and formulate appropriate technology based on the waste entrepreneurship (wastepreneurship) concept. The methods of this study were conducting calculation of waste characteristics and composition, social evaluation, and economic evaluation of the combination of composting, incinerator, and sanitary landfill. Waste characteristics and composition were taken using direct field measurement following Indonesia's National Standard Guideline about retrieving and measuring examples of urban waste emergence and composition. Characteristics of waste are used for the calculation of calorific value and energy. The social evaluation was conducted using an in-depth interview with the rag pickers. The economic evaluation was conducted using net present value, internal rate of return, and payback period. The result of the study shows that Piyungan Landfill with total combustion waste reach 82.22% has the potential of incinerator implementation. In social evaluation, the implementation of composting and incinerator technologies would open employment for the surrounding community and rag pickers. The economic evaluation shows the combination of composting and incinerator technologies was economically feasible with an average profit margin of 12.97% in the operational period of 18 years. In conclusion, the concept of wastepreneurship is relevant in Piyungan Landfill by adjusting the MSW management paradigm from previously cost-center into business-center.

Faktor-Faktor yang Mempengaruhi Pembuangan Sampah Pasar Tradisional Darfuar Kabupaten Biak Numfor Tahun 2020

The waste problem has become a serious problem, especially in big cities, not only in Indonesia, but throughout the world. Waste production that continues to increase along with population growth, changes in consumption patterns, people's lifestyles has increased the amount of waste piles, types and diversity of waste characteristics. This study aims to determine the factors that influence the disposal of waste from the Darfuar traditional market in Biak Numfor Regency. This type of research is a quantitative analytic which tries to explore and why health phenomena occur, with a cross sectional design. The population in this study were 234 respondents. The sample in this study were 147 respondents, where the sampling was random sampling. The results of the chi-square statistical test obtained the value of X2 count = 4.506 (X2 table = 3.841), the value of ? = 0.039. Thus the calculated X2 is greater than the X2 table or ? = 0.039 is smaller than ? = 0, the X2 count = 6.835 (X2 table = 3.841), the value ? = 0.015. Thus X2 count is greater than X2 table or ? = 0.015 is smaller than ? = 0.05, the value of X2count = 9.093 (X2 table = 3.841), the value of ? = 0.004. Thus X2 count is greater than X2 table or ? = 0.004 smaller than ? = 0.05, so Ho is rejected and Ha is accepted, meaning that there is an influence between waste facilities on Darfuar Market Waste Disposal in Biak Numfor Regency in 2020.

Application of Electrocoagulation with a New Steel-Swarf-Based Electrode for the Removal of Heavy Metals and Total Coliforms from Sanitary Landfill Leachate

Sanitary landfill leachate (LL) composition varies according to climate variables variation, solid waste characteristics and composition, and landfill age. Leachate treatment is essentially carried out trough biological and physicochemical processes, which have showed variability in efficiency and appear a costly solution for the management authorities. Electrocoagulation (EC) seems a suitable solution for leachate treatment taking into account the characteristics of the liquor. One of the problems of EC is the electrode passivation, which affects the longevity of the process. One solution to this problem could be the replacement of the electrode by one made of recyclable material, which would make it possible to change it frequently and at a lower cost. The objective of the present work was to evaluate the removal of heavy metals (As, Ba, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Se and Zn) and coliforms from a LL by EC using electrodes made from steel swarf (SfE) up to 8 h. Removal efficiencies of detected heavy metals were 51%(Cr), 59%(As), 71%(Cd), 72%(Zn), 92%(Ba), 95%(Ni) and >99%(Pb). The microbial load of coliforms in leachate was reduced from 10.76 × 104 CFU/mL (raw leachate) to less than 1 CFU/mL (after treatment with SfE) (i.e., approximately 100% reduction). The use of SfE in EC of LL is very effective in removing heavy metals and coliforms and can be used as alternative treatment solution for such effluents.