Thesis (MSc Food Sc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: The wine industry significantly contributes to South Africa's water demand and
subsequent pollution of the limited resource. Wastewater is produced throughout
the year with an increase in volume and organic load during the vintage season.
Anaerobic digestion (AD), specifically the upflow anaerobic sludge bed (UASB)
technology has been shown to be feasible in the treatment of cellar wastewater.
However, the legal standard for chemical oxygen demand (COD) for disposal in a
natural water resource (75 rnq.L") is often not met. The aim of the study was to
conduct a laboratory-scale investigation into the feasibility of combining pre- and
post-ozonation processes with AD in order to achieve a final COD closer to the
legal disposal limit.
While acclimatising an UASB bioreactor containing mixed anaerobic
granules to a cellar wastewater with a pH set at 8.0, stable-state conditions were
not reached. Sucrose additions to the substrate, increased substrate loads, heattreatment
of the substrate and an addition of isolated cellar effluent bacteria to
facilitate degradation prior to AD, were all unsuccessful in maintaining stable-state
in terms of COD removal efficiency. Once the substrate pH was re-set to 7.5, the
reactor stabilised. The lowest efficient operational pH was found to be 5.73
resulting in a COD removal of 88% at a substrate COD < 5 000 rnq.L". At a
substrate pH of 6.0, the lowest efficient operational hydraulic retention time (HRT)
and corresponding organic loading rate (OLR) were 19.7 hand
9.75 kg COD.m-3d-1
, respectively, with the COD removal being maintained around
84%. The reactor effluent still had a final COD of 1280 rnq.L", which was well
above the legal South African limit.
Dominant bacteria were isolated from raw cellar wastewater and identified
as Acinetobacter haemolyticus, Burkholderia cepacia and Cryseomonas luteola.
In order to investigate the possibility that ozonation improved biodegradability, the
growth of the isolates at 35°C was monitored over 24 h in sterile ozonated and
non-ozonated substrates from the vintage and non-vintage seasons. All the
isolates increased by at least 1.5 log cycles in the control substrates from both
seasons. Ozonation of the wastewater batches for 10 min at a rate of 73 rnq.L"
led to slightly increased growth of the inoculants in the substrate batch from the vintage season. For the substrates from the non-vintage season, ozonation had
an inhibitory effect on the bacterial growth.
A 5 min ozonation treatment at a concentration of 73 rnq.L" was found to
be optimal for both a pre- and post-treatment to UASB-treatment of cellar
wastewater. Both UASB treatment and ozonation were effective in reducing the
COD by 85% and 20%, respectively. The COD reduction was improved to 88%
when UASB treatment was combined with post-ozonation. The total reduction in
total suspended solids (TSS) for the combined process was 97%, compared to
80% for UASB and 73% for an ozone treatment alone. The reduction for volatile
suspended solids (VSS) was 98% compared to 81% for UASB and 73% for the
ozone treatment alone. The total reduction when using a pre-ozonation UASB
treatment combination was an average of 86% for COD. The TSS and VSS were
both reduced by 95%. Biogas production increased from 1.4 L.d-1 to 3.8 L.d-1
when an ozonated wastewater was used as substrate. When the UASB treatment
was combined with both a pre- and post-ozonation treatment process, the COD
was reduced by 89% while TSS and VSS were both reduced by 99%.
This study showed that pre- and post-ozonation treatment processes could
successfully be utilised to improve UASB treatment of cellar wastewater. Although
the legal limits for discarding into a natural resource were not met, significant
progress was made in reducing COD levels. Cellar wastewaters do however, vary
according to season and the wastewater composition could affect the efficiency of
a pre-ozonation process. / AFRIKAANSE OPSOMMING: Die wynindustrie maak "n beduidende bydrae tot die eise wat aan Suid-Afrika se
waterbronne gestel word en gevolglik die besoedeling van die beperkte hulpbron.
Afloopwater, wat in volume en organiese lading gedurende die parstyd toeneem,
word reg deur die jaar opgelewer. Anaërobiese vertering (AV), spesifiek die
"Upflow anaerobic sludge blanket" (UASB) tegnologie, is alreeds suksesvol
gebruik om kelderafloop te behandel. Die wetlike vereiste vir chemiese suurstof
behoefte (CSB) vir storting in "n natuurlike hulpbron (75 rnq.L"), word egter
dikwels nie bereik nie. Die doel van die studie was om in "n laboratorium-skaal
ondersoek AV te kombineer met voor- en na-osoneringsprossesse, om sodoende
te poog om "n CSB nader aan die wetlike standaard te verkry.
Terwyl"n UASB bioreaktor wat gemengde anaerobiese granules bevat het,
geakklimatiseer is tot kelderafloop met "n pH gestel tot 8.0, kon stabiele toestande
nie bereik word nie. Die byvoeging van sukrose tot die substraat, verhoogde
substraatladings, hitte-behandeling van die substraat en die byvoeging van
geïsoleerde kelderafloop bakterië om substraatafbraak voor AV aan te help, was
onsuksesvol om stabiliteit in terme van CSB-verwydering, te handhaaf. "n
Verstelling van die substraat pH na 7.5, het gelei tot reaktorstabiliteit. By die
laagste doeltreffende bedryfs-pH van 5.73 en substraat CSB < 5 000 rnq.L", was
die CSB-verwydering 88%. By "n substraat pH van 6.0 was die laagste
doeltreffende bedryfs-hidroliese retensie tyd en -organiese ladingstempo 19.7 h en
9.75 kg CSB.m-3d-1, onderskeidelik, terwyl die CSB verwydering rondom 84%
gehandhaaf is. Die CSB van die reaktoruitvloesel van 1 280 rnq.L", was steeds
ver bo die wetlike vereiste.
Dominante bakterië is uit kelderafloop geïsoleer en as Acinetobacter
haemolyticus, Burkholderia cepacia en Cryseomonas luteola, geïdentifiseer. Die
moontlikheid dat osonering bioafbreekbaarheid bevorder, is ondersoek deur die
groei van die isolate by 35°C oor 24 h in steriele geësoneerde en ongeësoneerde
substrate te monitor. Die substrate is berei vanaf kelderafloop wat in die
parsseisoen sowel as die nie-parsseisoen versamel is. AI die isolate het met ten
minste 1.5 log siklusse in die kontrole substrate van beide seisoene, vermeerder. Vir die kelderafloop wat in die parsseisoen versamel is, het osonering vir 10 min
teen 73 rnq.L" gelei tot effens verbeterde groei van die innokulante. Osonering
het 'n onderdrukkende effek op die groei van bakterië in die afloopwater versamel
in die nie-parsseisoen, gehad.
Osonering vir 5 min teen 'n konsentrasie van 73 rnq.L" is as optimum vir
beide voor- en na-osoneringsbehandeling tot UASB-behandeling van die
kelderafloop, gevind. UASB-behandeling en osonering het die CSB met 85 en
20% onderskeidelik, verminder. Die vermindering kon tot 88% verhoog word
wanneer UASB-behandeling met na-osonering gekombineer is. Die vermindering
in totale gesuspendeerde vastestowwe (TGV) vir die gekombineerde proses was
97%, in vergelyking met 80% vir UASB- en 73% vir osoonbehandeling alleen. Die
vermindering in vlugtige gesuspendeerde vastestowwe (VGV) was 98% in
vergelyking met 81% vir UASB- en 73% vir osoonbehandeling alleen. Die totale
CSB verwydering vir 'n voor-osonerings UASB kombinasie was gemiddeld 86%.
Die TGV en VGV is beide met 95% verminder. Biogasproduksie het ook
vermeerder vanaf 1.4 L.d-1 tot 3.8 L.d-1 toe geosoneerde afloopwater as substraat
gebruik is. Die kombinasie van UASB-behandeling met voor-osonering, sowel as
na-osonering het gelei tot 'n CSB-verwydering van 89% terwyl TGV en VGV beide
met 99% verminder is.
Hierdie studie het getoon dat voor- en na-osonering suksesvol gebruik kan
word om UASB-behandeling van kelderafloop te verbeter. Hoewel wetlike
vereistes vir storting in 'n natuurlike hulpbron nie bereik is nie, is beduidende
vordering gemaak in die verlaging van CSB-vlakke. Die verskil in die samestelling
van kelderafloop gedurende die onderskeie seisoene, kan egter die
doeltreffendheid van die voor-osoneringsproses beïnvloed.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/53749 |
| Date | 03 1900 |
| Creators | McLachlan, Tania |
| Contributors | Sigge, G. O., Britz, T. J., Stellenbosch University. Faculty of AgriSciences. Dept. of Food Science. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 129 pages |
| Rights | Stellenbosch University |
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