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Characteristics of Tofu Wastewater From Different Soybeans and Wastewater at Each Stage of Tofu Production

Hardyanti Nurandani, Susanto Heru, Budihardjo Mochamad Arief, Purwono, Saputra Angga Tri

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 8

54--63

EN

Tofu wastewater is a liquid by-product of the tofu production process that typically contains high levels of organic matter, such as proteins, carbohydrates, and fats, as well as other compounds, such as nitrogen, phosphorus, potassium, and COD. Tofu wastewater COD levels can vary depending on the type of soybeans used in the production process and the stages of the production process. This study aimed to analyze the characteristics of tofu wastewater from various types of soybeans and the characteristics of wastewater at each stage of the production process. The research methods used were field research and laboratory tests. Field research was conducted by collecting samples from different types of soybeans and analyzing them in the laboratory. Meanwhile, laboratory tests were run by analyzing samples for various parameters such as Soybeans Protein, Chemical Oxygen Demand (COD), total suspended solids (TSS), Biochemical Oxygen Demand (BOD), ammonia, and fat oil. The results showed that Wonogiri Soybeans had the highest protein parameter, 19%. As far as the wastewater of seed samples, the Wonogiri Seed sample had the highest parameter results for TSS, COD, ammonia, and BOD, which are 444 mg/L, 4583.33 mg/L; 13.86 mg/L; and 3.481 mg/L, respectively. As for the fat oil parameter, the Red Seed sample achieved the highest result of 6264 mg/L. In the case of the samples from each washing stage, it is known that the washing sample parameter results are lower than the seed samples. The Red 1st Washing sample had the highest TSS, COD, fat oil, and BOD values, amounting to 316 mg/L, 4666.67 mg/L, 356 mg/L, and 2053.71 mg/L, respectively. In comparison, the highest fat oil parameter corresponded to the Wonogiri 1st Washing sample with a value of 11.78 mg/L. The B/C ratio of all samples is > 0.1 and is in the biodegradable zone. Thus, the samples are not only able to be treated through biological processes, but also able to be treated through physical and chemical processes to avoid the length of time for biological decomposition due to the acclimatization process of microorganisms to the samples.

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Pollution Load Capacity Assessment by Utilizing QUAL2E Modelling: A Case Study of Rambut River, Indonesia

Nugraha Winardi Dwi, Hadi Sudharto Purnomo, Sasongko Setya Budi, Istirokhatun Titik, Faradiba Faradiba, Nopita Ayu, Handayani Dwi Siwi, Muhammad Fadel Iqbal, Susanto Heru, Budihardjo Mochammad Arief

Journal of Ecological Engineering

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2022

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Vol. 23, nr 3

154--161

EN

Water quality modelling can be a way to determine the potential pollutant load capacity in the river water. As the number of population and intensity of activities around the river increased, it is possible that the water quality in the river will be negatively impacted. The Rambut river, which located in Pemalang and Tegal, Indonesia, has an important role as a water source in both areas. However, this demand is not accompanied by the availability of river capacity information yet. Five points from different segments along the upstream and downstream of Rambut River were assessed with the QUAL2E model. There were four different parameters in the research, e.g., BOD, fecal coliform, nitrite, and nitrate. The results showed that some segments did not comply with the minimum requirements by the local government. Additionally, the BOD and fecal coliform value were predicted to be increased in 2023 due to higher population number living near the river. The values for all parameters fluctuated between the different segments.

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Performance evaluation of nanofiltration membranes for dye removal of synthetic hand-drawn batik industry wastewater

Desiriani Ria, Susanto Heru, Aryanti Nita

Environment Protection Engineering

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2022

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Vol. 48, nr 1

51--68

EN

This study evaluated the performance of nanofiltration (NF) membrane for the treatment of hand-drawn batik wastewater containing synthetic dyes as well as real batik wastewater. Three commercial NF membranes (NF270, TS40 and XN45) were used. The effect of transmembrane pressure, NF membrane types, synthetic dyes concentration, and solution types on flux and rejection were investigated. The results showed that the use of all NF membranes could reach dye removal of ca. 99%. NF270 membrane exhibited the highest flux, 2–3 times higher than that of TS40 and XN45 membranes. NF270 membrane was further used for treating real batik wastewater. The results showed high rejections in terms of total suspended solids (TSS), chemical oxygen demand (COD), and total dissolved solids (TDS) were obtained. The practical applicability of NF270 membrane for real handdrawn batik wastewater treatment fulfilled the quality standards in terms of TSS, COD, and BOD parameters. Overall, the NF270 membrane showed favorable performance for batik effluent treatment.

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Game theory analysis in Indonesia’s shipping industry: Case study agreement between PT. X and PT. Y

Susanto Heru

Scientific Journal of Gdynia Maritime University

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2020

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nr 113

7--16

EN

Nowadays, the container shipping industry in Indonesia has a tendency to oligopoly, even in one shipping route. Two big shipping liners in Indonesia, PT. X and PT. Y, have been dominating sales on the Surabaya-Banjarmasin route. The aim of this study is to know how the liners behave in an oligopoly, making decisions that are profitable for both parties. The agreement on challenge, competition, and cooperation between PT. X and PT. Y in serving shipping services is the main focus in this study. The methodology used is a game theory approach to show the possible strategies in rates and supply competition. The result shows that the agreement between PT. X and PT. Y consisted of price decision and supply quantity. The price decision is rated at a lower price of USD 300/TEU where P = MC which has no incentive. While the agreement on supply quantity is 26.000 TEUs in total. Moreover, the cooperative agreement between the shipping liners is a joint allience which not depend on each capacity ratio.