Anaerobic Digestion of Wastewater Derived from the Pressing of Orange Peel Generated in Orange Juice Production
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- 作者：José ; Á ; ngel Siles ; Marí ; a de los Á ; ngeles Martí ; n ; Antonio Martí ; n ; Francisco Raposo ; Rafael Borja
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2007
- 出版时间：March 7, 2007
- 年：2007
- 卷：55
- 期：5
- 页码：1905 - 1914
- 全文大小：231K
- 年卷期：v.55,no.5(March 7, 2007)
- ISSN：1520-5118
文摘
A study of the anaerobic digestion of wastewater from the pressing of orange peel generated inorange juice production was carried out in a laboratory-scale completely stirred tank reactor atmesophilic temperature (37 
C). Prior to anaerobic treatment the raw wastewater was subjected tophysicochemical treatment using aluminum sulfate as a flocculant and to pH reduction using a solutionof sulfuric acid. The reactor was batch fed at COD loads of 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0g of COD. The process was very stable for all of the loads studied, with mean pH and alkalinityvalues of 7.5 and 3220 mg of CaCO3/L, respectively. The anaerobic digestion of this substrate wasfound to follow a first-order kinetic model, from which the specific rate constants for methaneproduction, KG, were determined. The KG values decreased considerably from 0.0672 to 0.0078 L/(gh) when the COD load increased from 1.5 to 5.0 g of COD, indicating an inhibition phenomenon inthe system studied. The proposed model predicted the behavior of the reactor very accurately, showingdeviations of <5% between the experimental and theoretical values of methane production. Themethane yield coefficient was found to be 295 mL of CH4 STP/g of COD removed, whereas themean biodegradability of the substrate (TOC) was 88.2%. A first-order kinetic model for substrate(TOC) consumption allowed determination of the specific rate constants for substrate uptake, KC,which also decreased with increasing loading, confirming the above-mentioned inhibition process.Finally, the evolution of the individual volatile fatty acid concentrations (acetic, C2; propionic, C3;butyric, C4; isobutyric, iC4; valeric, C5; isovaleric, iC5; and caproic, C6) with digestion time for allloads used was also studied. The main acids generated were acetic and propionic for all loads studied,facilitating the conversion into methane.
C). Prior to anaerobic treatment the raw wastewater was subjected tophysicochemical treatment using aluminum sulfate as a flocculant and to pH reduction using a solutionof sulfuric acid. The reactor was batch fed at COD loads of 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0g of COD. The process was very stable for all of the loads studied, with mean pH and alkalinityvalues of 7.5 and 3220 mg of CaCO3/L, respectively. The anaerobic digestion of this substrate wasfound to follow a first-order kinetic model, from which the specific rate constants for methaneproduction, KG, were determined. The KG values decreased considerably from 0.0672 to 0.0078 L/(gh) when the COD load increased from 1.5 to 5.0 g of COD, indicating an inhibition phenomenon inthe system studied. The proposed model predicted the behavior of the reactor very accurately, showingdeviations of <5% between the experimental and theoretical values of methane production. Themethane yield coefficient was found to be 295 mL of CH4 STP/g of COD removed, whereas themean biodegradability of the substrate (TOC) was 88.2%. A first-order kinetic model for substrate(TOC) consumption allowed determination of the specific rate constants for substrate uptake, KC,which also decreased with increasing loading, confirming the above-mentioned inhibition process.Finally, the evolution of the individual volatile fatty acid concentrations (acetic, C2; propionic, C3;butyric, C4; isobutyric, iC4; valeric, C5; isovaleric, iC5; and caproic, C6) with digestion time for allloads used was also studied. The main acids generated were acetic and propionic for all loads studied,facilitating the conversion into methane.