การบำบัดและผลิตก๊าซชีวภาพจากขยะอาหารด้วยระบบไร้ออกซิเจนแบบท่อไหล

Treatment and Biogas Production from Food Waste Using a Plug Flow Reactor

Name: ปิยชน สังข์กลิ่นหอม

Name: Piyachon Sangklinhom

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

keyword: Biogas

; Food Waste

; Hydraulic Retention Time

; Methane

; pH Effect

; Plug Flow Reactor

; Total Solids

; Treatment

Abstract: The research was studied on treatment and biogas production from food wastein a plug flow reactor. The reactor has 12 liters of working volume and was constructedwith baffles which devided the reactor into 20 compartments. The system of baffles useto prevent short circuit in the reactor. The aim of this research was to study the effect ofhydraulic retention time (HRT), total solid content and pH controls at the inlet of reactoron the performance of anaerobic plug flow reactor.To study the effects of HRT, the reactor was operated at HRTs of 20, 10 and 7days with a feed solid content of 1% which corresponding OLRs of 0.75, 1.50 and 2.15kgCOD/m3-d, respectively. At HRTs of 7-10 days, treatment and biogas production waswell performed. The results showed that COD reduction, methane yield and biogasproduction rate were 80-90%, 0.11-0.14 m3/kgCOD removed and 0.25-0.50 v/v-d,respectively. Acidogenic fermentation was more active within one-third of longitudinaldistance of the reactor, indicated by maximum total volatile acid (TVA) of 4,000 mg/lin the first compartment of the reactor. To study the effects of feed solid concentrationsof food waste, experiments were conducted with feed total solids (TS) of 2, 5 and 10%.Suddenly increased feed TS from 5 to 10% exhibited harmful to balanced acidoginicand methanogenic fermentation that resulted in the acid production was over than theacid utilization. The later experiments were conducted by gradually increase feed TSfrom 2 to 5 and 7.5%. At feed TS of 5 and 7.5%, the efficiency of treatment and biogasproduction were similar in the range of 75-85% and 0.10-0.11 m3/kgCOD, respectively.At feed TS of 7.5%, methane production rate was maximum at 1.82 v/v-d. Acidogenicfermentation predominanted on one-third of longitudinal distance of the reactor,indicated by maximum TVA of 10,000 mg/l in the seventh compartment. The effects ofpH controls were studied at the condition of feed TS of 7.5% and HRT of 10 days.Increasing pH at the inlet of reactor from actual pH of 4.5 to 5.5 and 6.5, degradation oforganic substance into volatile acids increased from 10,000 mg/l to 22,000 and 25,000mg/l, respectively. Methane yields also increased from 0.11 m3/kgCOD to 0.15 and 0.22m3/kgCOD, respectively. Increasing inlet pH to 7.5, the acid production was over thanthe acid utilization and decreased the efficiency of treatment and biogas production.The suitable condition for this research was at feed TS of 7.5%, HRT of 10days and controlled inlet pH at 5.5. The methane production rate was 2.52 v/v-d.Composition of methane in biogas was 60%. COD removal efficiency was 70%.It was noticed that the plug flow reactor exhibited higher stabilizationefficiencies with food waste treatment than those obtained with one stage and two stagereactors. Calculation of biogas cost from food waste compare to other fuels cost wereconducted. The cost of produced biogas is 1.48 baht/m3, compared with fuel oil (gradeC), LPG, diesel oil and gasoline which were 215.36, 139.39, 363.54 and 495.24baht/GJ, respectively.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร

Email: info.lib@mail.kmutt.ac.th

Name: ภาวิณี ชัยประเสริฐ

Role: อาจารย์ที่ปรึกษา

Created: 2545

Issued: 2005-10-03

Modified: 2554-03-05

ISBN: 9749636384

CallNumber: ET533

tha

DegreeName: วิศวกรรมศาสตรมหาบัณฑิต

Level: ปริญญาโท

Descipline: เทคโนโลยีพลังงาน

Grantor: มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

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