Influence of Organic Fraction of Municipal Solid Waste Particle Size on Biogas Production

The performance of anaerobic digestion (AD) to process organic fraction of municipal solid waste (OFMSW) can be improved with various pre-treatments. Mechanical pre-treatments, mainly chopping, have shown to be the most economical and relatively effective method to increase contact between the substrate and microorganisms. The purpose of this research was to analyze the effect of OFMSW particle size on CH4 gas formation in a laboratory-scale Biochemical Methane Potential (BMP) assay. The research was conducted for 35 days at a temperature of 35°C with three sizes of OFMSW co-digested with cow manure. OFMSW with particle sizes of 10-13 mm, 4.76-10 mm, and 2-4.76 mm produce CH4 gas with an average of 114.7+14.7 ml, 101.7+0.5 ml, and 110.9+10.8 ml, respectively, while methane yield was 0.277 L CH4/g VS, 0.208 L CH4/g VS, and 0.229 L CH4/g VS, respectively. Particle size is more likely to have an influence on the hydrolysis and acidogenesis processes, as demonstrated by the significant difference of VFA value, but not on the biogas potential. Particle sizes of 13-15 mm produce 19.25 mg VFA/L, while the size range of 2-4.76 mm produces 118.1 mg VFA/L

Faktor-faktor yang memengaruhi minat mahasiswa sarjana untuk melanjutkan studi magister

Program Magister Teknik Lingkungan Universitas Indonesia merupakan program studi baru sehingga diperlukan upaya dalam menarik peminat. Program tersebut berada dibawah Departemen Teknik Sipil dan Lingkungan yang merupakan pengembangan dari program magister teknik sipil kekhususan teknik lingkungan. Semenjak berdirinya Magister teknik sipil dengan kekhususan teknik lingkungan pada tahun 2010, mahasiswa yang berasal dari lulusan program sarjana di departemen yang sama masih sedikit jumlahnya. Tujuan penelitian ini untuk menganalisis pengaruh sikap, norma subjektif, kontrol perilaku serta kualitas pelayanan terhadap minat mahasiswa program sarjana untuk melanjutkan studi pada Program Magister Teknik Lingkungan.  Metode yang digunakan dalam penelitian ini adalah kuantitatif dengan menggunakan SEM-PLS yang didasarkan pada Theory of Planned Behavior dan Service Quality (SERVQUAL). Responden dalam penelitian ini adalah 110 mahasiswa program sarjana tingkat akhir dan masih aktif di Departemen Teknik Sipil dan Lingkungan Universitas Indonesia. Hasil penelitian menunjukkan bahwa sikap dan norma subjektif berpengaruh signifikan terhadap minat mahasiswa program sarjana untuk melanjutkan studi program Magister Teknik Lingkungan Universitas Indonesia

Wastewater Disinfection Efficiency Using One- Step and Two-Step Chlorination

One-step chlorination (OSC) is a common method, generally implemented as the last step of wastewater treatment plants (WWTPs) and water treatment plants (WTPs). Improving disinfection efficiency is necessary to increase pathogen and organic matter removal. Two-step chlorination (TSC) has been studied as a new method of chlorination. This study aimed to compare OSC and TSC efficiency for coliform and organic matter removal. Chlorination was performed in a batch system and at laboratory scale using calcium hypochlorite. Samples were collected from WWTP effluent in an industrial estate located in Indonesia. The samples underwent the adsorption process beforehand. Chlorine dosage at 10-110 mg/L, at a 10-200-second time interval, and with a dosage ratio of 3:1-7:1 were evaluated. Results showed that the optimum dose for OSC is 80 mg/L. The optimum condition for TSC is a 50-second time interval and a 5:1 dosage ratio between the two steps. With the same total dose as in OSC, TSC improved efficiency for COD, BOD, and coliform removal up to 12%, 35%, and 0.39-log reduction, respectively (p < 0.05). Moreover, trihalomethane (THM) formation was reduced up to 13% by using the TSC method. However, an increasing ammonia concentration occurred because of the OSC and TSC processes (p < 0.05)

Integration of water, sanitation, and hygiene program with biosecurity: A One Health approach to reduce the prevalence and exposure of antibiotic-resistant bacteria in the livestock community

The global spread of antibiotic resistance poses a significant threat to public health and is one of the main causes of this problem. Livestock farming plays a significant role in the horizontal and vertical transmission of treatment-resistant genes and bacteria. These processes involve contact with agricultural products and the environment, raising concerns for public health, and farming communities. The farming community is composed of a staggering 608 million farms worldwide, and their livelihood depends heavily on livestock farming. To address this issue, a multidisciplinary One Health approach focusing on integrated monitoring and intervention for humans, animals, and the environment is essential. Water, sanitation, and hygiene (WaSH) programs have the potential to significantly reduce the risk of exposure to antibiotic-resistant bacteria, particularly extended spectrum beta-lactamase (ESBL) Escherichia coli, by obstructing the transmission route between humans and animals. Additional risk reduction measures for ESBL E. coli infection in animals include vaccination and biosecurity program implementation. Water, sanitation, and hygiene and biosecurity measures must be combined to maximize the effectiveness of the One Health program. Therefore, this study aimed to describe recent advances in biosecurity and WaSH interventions in the livestock environment, analyze the effects of these interventions on human and animal health, and investigate potential future scenarios within the quantitative microbial risk assessment framework. This study used an integrative literature review through searches of four databases, a review of World Health Organization documents through websites, and an examination of relevant texts from previously obtained reference lists. Although hygiene and sanitation are often combined, there is still a lack of quantitative evaluation of the efficacy of integrating WaSH with biosecurity in livestock. In addition, the integration of the WaSH program with biosecurity has potential as a One Health intervention in the coming years

The Effect of Magnesium Sulfate Addition on Volatile Solid Destruction and Chemical Oxygen Demand Reduction of Food Waste Anaerobic Digestion

Process instability often occurs in anaerobic digestion (AD) due to inhibitors, such as the high sodium content in food waste. Recent studies have reported that magnesium can reduce the sodium ion’s toxicity towards methanogens. This study aimed to analyze the effect of magnesium addition to Volatile Solids Destruction (VSD), Chemical Oxygen Demand (COD) reduction, and biogas production in AD of food waste. The experiment consisted of two phases, the control phase and the experimental phase, without and with MgSO4, respectively. The control phase results were: average COD reduction, VSD, and methane yield up to 80.9%, 87.6%, 340 mL CH4/gr VS/day, respectively. The experimental phase results were: average COD reduction, VSD, and methane yield up to 78.5%, 83.9%, 125 mL CH4/gr VS/day, respectively. Overall, the study’s results showed that MgSO4 had a negative impact on VSD and methane yield. The addition of MgSO4 seemed to cause instability in the AD system, which resulted in a decrease in the VSD value and a decrease in the methane concentration.&nbsp

Anaerobic Digestion Potential in Traditional Boarding School

There are approximately 36,600 religious boarding schools in Indonesia accommodating a student population of 3.4 million. Traditional religious boarding school is one of the most significant contributors to waste generation after housing. This study is aimed to measure waste generation and the potential to implement anaerobic digestion in traditional boarding schools. At Al Hikam Boarding School, with a population of 265 residents, the average daily waste generation was measured at 33.6 kg/day, with organic waste constituting 41.8%. Over three months, the study included the stages of seeding, acclimatisation, and operation of anaerobic digestion using organic waste generated by the boarding school and traditional buffet. With an input of 7.6 kg/day, the results showed that organic waste used had a pH, total solid (TS), volatile solid (VS), chemical oxygen demand (COD), and temperature of 6.1±0.38, 25±0.092%, 95±0.0054%TS, 453±188 g/L, and 29.5±1.12°C, respectively. The digester reported a volatile solid destruction (VSD) and chemical oxygen demand (COD) reduction of 91±0.015% and 89±0.081%, respectively. This produced biogas volume and methane yield of 805±219 L/day and 292±130 L.methane/kg.VS. So, anaerobic digestion with a Toren Biogas reactor is the recommended technology to manage organic waste at traditional boarding schools, with a potential reduction factor of 54%.</p

Water Recycling Opportunity in the Business Sectors of Greater Jakarta, Indonesia

With increasing population, climate change and limited water, water reuse is an option that must be explored to reduce the high water stress in Indonesia. This study aims to identify enablers, barriers, and opportunities from early adopters of water recycling in the business sector of the Greater Jakarta Region to highlight possibilities of its wider implementation in order to reduce water stress. Semi-structured interviews, desk review, and observations were conducted to eight enterprises. Most respondents demonstrated that their main purpose for water recycling is cost-saving. Recycled water was mostly used with minimum direct contact possibilities with people to reduce risk from social barriers. While the absence of a clear legal framework was identified as another barrier to water recycling implementation, it can also be an enabler. The decrease in raw water quality make water recycling a cost-effective solution. Considering all findings, water recycling in Indonesia has great opportunity to be further applied and supported by related stakeholders

Implementation of Cleaner Production in a Natural Dye

Utilization of natural dye in batik industry is a preventive solution taken to avoid environmental problems. Natural dyes is used to substitute synthetic dyes, naphtol and indigosol which has COD of 10.000-20.000 mg/L. Although the solution has been taken, the wastewater quality still exceed the limits stated on Regulation of the Ministry of the Environment No.5/2014. The research aim is to generate cleaner production solution, specifically material substitution and process modification to increase biodegradability. The implementation is conducted six times. The research process is pre-assessment of natural dye and batik wastewater, implementation of material substitution in mordanting, washing material and process modification. Natural dyes used has BOD of 203-975 mg/L, COD 1.316-2.453 mg/L and BOD/COD 0,1-0,4. Through statistical analysis with 95% level of confidence, the results show no significant changes to BOD, COD, BOD/COD as well as colour reduction. The results of options implemented is BOD value of 99-450 mg/L, COD 402-1.102 mg/L, TSS 105-540 mg/L, colour 291-2.408 Pt-Co and BOD/COD 0,2-0,4. Hence, wastewater treatment is needed and unit designed for wastewater flow of 0,09 m3/day is anaerobic baffled reactor with the size of 0,6 m x 0,45 m x 0,5 m, HRT of 36,4 hour and SRT of 6 days