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Eutrophication is an inevitable phenomenon, and it has recently become an unabated threat. As a positive, the thriving microalgal biomass in eutrophic water is conventionally perceived to be loaded with myriad valuable biochemical compounds. Therefore, a sugarcane-bagasse-based adsorbent was proposed in this study to harvest the microalgal biomass for producing biodiesel. By activating the sugarcane-bagasse-based adsorbent with 1.5 M of H2SO4, a highest adsorption capacity of 108.9 ± 0.3 mg/g was attained. This was fundamentally due to the surface potential of the 1.5 M H2SO4 acid-modified sugarcane-bagasse-based adsorbent possessing the lowest surface positivity value as calculated from its point of zero charge. The adsorption capacity was then improved to 192.9 ± 0.1 mg/g by stepwise optimizing the adsorbent size to 6.7–8.0 mm, adsorption medium pH to 2–4, and adsorbent dosage to 0.4 g per 100 mL of adsorption medium. This resulted in 91.5% microalgae removal efficiency. Excellent-quality biodiesel was also obtained as reflected by the fatty acid methyl ester (FAME) profile, showing the dominant species of C16–C18 encompassing 71% of the overall FAMEs. The sustainability of harvesting microalgal biomass via an adsorption-enhanced flocculation processes was also evidenced by the potentiality to reuse the spent acid-modified adsorbent.

ABSTRACT Palm oil is one of the potential commodities that is widely cultivated by farmers in Singingi Hilir Regency. This study aims to analyze the farmers’ characteristics and profile of oil palm farming, the use of factors of production, costs, production, income and efficiency of oil palm farming, and the effect of production factors on oil palm farming productivity. The research was conducted during 6 months, starting from September 2018 to February 2019. Survey location was selected in Sungai Buluh Village Kuantan Singingi Hilir District Kuantan Singingi Regency and samples were purposively selected as 38 farmers. The samples were farmers who have oil palm farming with age between 10-15 years. Data were collected by survey method, consisting of primary data and secondary data. The results showed that the average age of farmers was 46.32 years, the education level of farmers averaged 9.61 years, the average number of family members was 4 person with having experience on oil palm cultivation was 13.84 years. The average of farmers’ land area was 3.63 ha. The average of oil palm production cost was IDR 40,227,034/year, consisting of variable costs of IDR 39,818,783 and fixed costs of IDR 408,251.  The average of oil palm production in fresh fruit bunch was 64,740 kg/year with a selling price of IDR 1,449/kg and revenue was IDR 93,813,371/year. Moreover, the profit obtained was IDR 53,586,337/year and efficiency value (RCR) was 2.33. The land area and urea fertilizer had a significant effect on palm oil productivity in Sungai Buluh Village, Singingi Hilir District, Kuantan Singingi Regency. Keywords:Production factors, Oil palm farming, Productivitas, Swadya pattern.

Milling process is the most completely mechanized in rice farming operations in Kampar Regency, Indonesia. Small-scale rice mills are the most popular used by rice farmers and widely distributed over paddy areas in the region. Accordingly, a survey was conducted to recognize the distribution and use patterns of the small-scale rice mills. A total of 20 small-scale rice mills were observed from selected districts of the regency and the machines' owners and operators were interviewed to collect field data. The results showed that the distribution of the small-scale rice mills was concentrated in a wider area of paddy field with a high level of production due to a high demand of milling rice in the areas. Because of most farmers are subsistence in production and the rice will be milled when being consumed, so the small-scale rice mills could be operated along the year. The number of paddy milled in total for a year was 16.4 tonnes for rice mills with a capacity of 750 kg/h and 3.9 tonnes for rice mills with a capacity of 500 kg/h. However, the number of milled paddy varied across months with the peak demand for milling rice occurred after harvesting and before fasting month.