ความสูงและความหนาแน่นของชั้นวัสดุตัวกลางต่อประสิทธิภาพของถังปฏิกรณ์แบบลูกผสม

Efficiency of anaerobic hybrid reactors with different density and height of supporting media

Name: เถลิงเดช พิลาศรี

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

keyword: Anaerobic hybrid reactor

; density of supporting media

; height of packed zone

; nylon fiber

; starch wastewater

Abstract: An anaerobic hybrid reactor is developed to combine the advantage of upflow anaerobicsludge blanket (UASB) and fixed film/filter reactors. This is to prevent sludge wash out whenoperating at high flow rate and to decrease plugging and channeling on long term operation. Inaddition, an anaerobic hybrid reactor is partially filled with supporting media hence cost ofsupport media is reduced in compare with a filterlfixed film reactor. The aims of this work are tocompare efficiency of the anaerobic hybrid reactors with different density of nylon fiber assupporting media on treatment of starch wastewater, stability of the reactors at high organicloading rate (OLR) and short hydraulic retention time (HRT), and biomass and sludgedistribution at the sludge and packed zones.Each of the three hybrid reactors is 6 litre in volume and a height of 80 cm. The packedzone which is on the upper part of the reactor consists of nylon fiber with a surface area of 0.84m2. The length of the nylon fiber is 30, 40 and 50 cm and the density of packed area is 44, 33and 26 kilogram/m3 for the reactor No. 1,2 and 3 respectively. Feeding mode is continuously for323 days which is separated into 3 stages. Firstly, OLR is increased step by step from 0.5 to 1,2,3 and 4 kg.COD/m3 eactor/day with same HRT of 5 day. The second stage is to apply shockorganic and hydraulic loading rate to observe the ability of the reactor in tolerance with shockingloading. Liquid recirculation is includcd in thc last stage.The study showed over 95 % of COD reduction in all 3 reactors at OLR 10 kg/m3dayand 2 day HRT. The gas production was 14, 12 and 12 litrelday for reactor 1, 2 and 3respectively with 60% methane. More than 90 % of COD was removed in the sludge bed whenthe concentration of biomass was 133, 150 and 129 gram in reactor 1,2 and 3 respectively at day285. However, COD removal of the sludge bed decreased to 50-60 % when HRT was shortenedto 0.5-1 day with an increase in COD removal of the packed zone. Together, the overall CODreduction were 84, 80 and 87 % at OLR 6 kg/m3 /day and 0.5 day HRT, and 61, 66 and 83 % atOLR 10 kg/m3/day at 1 day HRT for reactor 1,2 and 3 respectively. Even though at the OLR of6 kg/m3/day, it was found that none of the three reactors was stable if operated at HRT less than1 day for a longer period. The reactor No. 3 with the lowest density but the highest height ofsupport media tolerated the shock hydraulic rate better than the other two reactors. As such, thereactor No.3 was operated 14 days longer than No.1 and 2 before failing. Nevertheless, allreactors recovered within a week.The amount of biomass trapped in the packed zone was 88, 60 and 46 gramand the sludge zonc was 66,74 and 65 gram in reactor 1,2 and 3, respectively at day 135. Withthe higher flow rate, biomass on the nylon fiber was reduced to 66, 58 and 31 gram and thesludge zone was 59,64 and 67 gram in reactor 1,2 and 3 respectively at day 185. The amount ofbiomass increased tremendously when increasing organic loading rate to 10 kg.COD/m3/day at292 day with 127, 106 and 116 gram on nylon fiber, and 119, 135 and 91 gram in the sludge ofreactor 1,2 and 3 respectively. A decrease in biomass suspension was recorded to 70,79 and 68gram with an increase of biomass in nylon fiber to 167, 197 and 181 gram in reactor 1, 2 and 3respectively when liquid was recirculated at the rate of 2,775 mllday for an hour a day duringday 317-323.It was found that the sludge bed was more expanded the longer theoperation. At OLR 6 kg/m3/day, HRT 2 day (day 243-255), the height of the sludge bedwas 10 cm in all reactors. At day 256-285 (OLR 10kg/m3/day, HRT 2 day), the height was 30,40 and 20 cm in Reactor 1, 2 and 3, respectively. The sludge bed was further expanded whenfaster flow rate (HRT 1 day) and the height was 40, 40 and 30 cm in reactor 1, 2 and 3respectively. The profile of biomass distribution of the packed zone indicated the higher amountof biomass on the upper part of the zone which was closed to the reactor outlet in allexperiments.Though the concentration of biomass was highest in reactor No. 1, it was found that itsCOD removal efficiency was only 0.69 on day 135 (OLR 4 kg/m3reactor/day HRT 5 day)compared with 0.89 and 0.97 gram COD removedgram VSS of reactor No. 2 and 3,respectively. The longer the operation, the efficiency of reactor 1, 2 and 3 decreased to 0.33,0.34 and 0.43 gram COD removedgram VSS on day 185, and 0.14, 0.15, 0.22 gradgram VSSon day 292, respectively. The efficiency was improved to 0.38, 0.32 and 0.39 gramlgram VSSfor reactor 1, 2 and 3 respectively when liquid circulation was applied on day 3 17-323 at the rateof 2,775 mVday for one hour a day.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร (Bangkok)

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

Name: ศ.ดร.มรากต ตันติเจริญ

Role: อาจารย์ที่ปรึกษา

Created: 2544

Issued: 2005-10-21

Modified: 2006-05-24

วิทยานิพนธ์/Thesis

ISBN: 9746287931

CallNumber: BIT350

tha

DegreeName: วิทยาศาสตรมหาบัณฑิต

Level: ปริญญาโท

Descipline: เทคโนโลยีชีวภาพ

Grantor: มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

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