An Investigation Of Biological Treatment And Aeration On Wastewater Effluent Maura Harty

46 Pages·2007·2.8 MB·English

An Investigation Of Biological Treatment And Aeration
On Wastewater Effluent
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Maura Haosres teoydn lfy .or any
Deeccti o2nw np0eurr 0rpe1qui r
For inysripght o
Project ma n u o na s el n t s ofu cbopmitted in partial fulfillment
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of examination requirements leading to the award of
Diploma in Applied Sciences
(Dublin Institute Of Technology)
And
B.Sc. (Applied Sciences)
(University Of Dublin)
Supervisiors : MI-Fr.an k Kennedy-Technical Manager, Cadbury Ireland Ltd.
Mr. Anthony Ross-Laboratory Manager, Cadbury Ireland Ltd.
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Abstract
Environmental analysis shows that effluent streams have been found to fall frequently
outside the pH specified by the local authority in to whose sewer the wastewater is
discharged. The accumulation of oils, fats and greases also poses a challenge to the
industry as its disposal is becoming more restrictive and costly.
The aim of this project was to determine if it was feasible to treat effluent in grease
traps, onsite, biologically by the method of Biological Aerated Filter Treatment to
effect a decrease on the loading of the grease thus bringing the wastewater quality
parameters within the required specification while maintaining a specified pH range
of 6-10.
A laboratory scale model of a grease trap, containing various effluent samples similar
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in concentration and composition to that entering the greaer sues traps on site, was treated
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binio cloongtiaccatl lwy ibthy aa nsu abttsatcrahteed ( PgVroCw)t hto s ymsetetamb ocloismoesep st hreodin elsfy. oirtn aagnry g oeft aw masitcer oabnido lsoog diceaclr peaospeu tlhatei on
loading in the model grease trap. The taecntikonw nwpeurr arpesq uairlso aerated to eliminate anaerobic
pcsiortoned dwuitceitorieno sna l wsthohu imsc hom nmaiitanoytra eliden aitdno g t i o n a o vn nf s ee e a nrs t mc t oifcF gecoeroa nipptnytestraipa gttbhiht vloeee plionHav do6iln-v1gi0 no.g nT a twh coee rottrafa iptnhs e.a mnionue ngt roefa saec itdra ps on
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The laboratory scale study revealed a decrease in all parameters of the wastewater
quality to within the'licencing limits, while effecting a rise in the pH to an average 6.3
pH units. However the study revealed a certain start up period / lag phase before
optimal biological activity occurred .The time in which it took for the wastewater
quality parameters to reach satisfactory levels was found to be outside the residence
time available for wastewater effluent in the grease traps on site.
It is evident by the laboratory project that the biological aerated system is successfbl
in regulating the quality parameters, but it is also clear that longer residence times are
required to optimise the performance of the biological aerated filter system. Larger
scale treatment facilities are required to ellivate such factors as residence time and
flow rates thus optimising the performance of the biological treatment system.
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f Acknowledgements.
I would like to thank Mr. Frank Kennedy, Technical Manager at Cadbury Ireland Ltd.,
for giving me the opportunity to work in the Technical Department of such a
prestigious company. The experience gained here invaluable and shall stand to me in
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the future, for this I am extremely gratehl.
A special word of thanks to p.Anthony Ross, Laboratory Manager. For the support
and encouragement he gave throughout the project. As project supervisor he gave
direction and advice whenever needed.
Many thanks to all the technical staff for their help and encoue.ragement. To Helen,
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Karen and for their interest in the progress of my project ahnd their help and advice
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which they willingly gave. oses eodn lfy.or any
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I would also like to thank Dr. Paul MFor ainytsrhipgihat so for his help and guidance with regard to the
completion of this project. o n s e n t of cop
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Last, but not least, I would like to thank my family and fiiends for their never-ending
help and support of which I am extremely grateful.
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I Table Of Contents
1. INTRODUCTION 6
1.1 Cadbury Ireland Ltd. 6
1.2 Industrial Wastewater 6
1.2.1 Current Environmental Position 6
1.2.2 Project Objective 6
1.3 Licencing of Wastewater Discharge in Ireland & The Importance
Of Wastewater Monitoring 9
1.4 Parameters Used To Evaluate The Quality Of Wastewater 10
1.4.1 Biochemical Oxygen Demand 10
1.4.2 Chemical Oxygen Demand 10
1.4.3 Suspended Solids 11
1 :4.4 Oils, Fats And Greases 12
1.4.5 pH 12
1.5 Biological Treatment e. 13
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1.5.1 Attached Growth Systems oth 13
1I S.5..32 BBiioofliolmgisc al Filter and Bioloosegs ieocdn lafy.olr Canoy ncentrate 1165
Expe rime n ta 1 0b j ective ectionw npeurr rpequir 18
2. MA2T.1E RPrIAo2j.Le Ic.S t1 M& a MMtearEti e aT r l iC Hsa o ln& ssO e n tED ofqF Scouro ipinpysripmght eont 111999
2.1.2 Equipment 19
2.2 Initial Proposal 19
2.3 Experimental Design
2.4 Determination Of Chemical Oxygen Demand Using Hach COD Meter 20
2.4.1 Introduction 21
2.4.2 Procedure 21
2.4.3 Analysis and Calculations 22
2.5 Determination Of Suspended Solids Using Vaccum Filtration 22
2.5.1 Introduction 22
2.5.2 Procedure 22
2.5.3 Interpretation Of Results
2.6 Determination Of pH Using pH Meter 23
2.6.1 Introduction 23
2.6.2 Calibration 23
2.6.3 Analysis 24
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2.7 Determination Of Biochemical Demand
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2.7.1 Introduction
2.7.2 Procedure 25
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2.8 Determination Of Oils, Fats And Greases
2.8.1 Introduction 26
2.8.2 Procedure 26
2.9 Determination of Total Solids using Belingham & Stanley RFM 26
2.8.3 Introduction 26
2.8.4 Procedure 26
2.10 Sample Collection by ISCO 6700 Autosampler 27
3. EXPERIMENTS & RESULTS 28
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3.1.1 Effect of Various Treatments On The Wastewater Paramaeters
3.1.2 Result Of Effect Of Treatments A, B, C, D & E On pH 28
3.1.3 Result Of Effect Of Treatments A, B, C, D & E On BOD 29
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3.1.4 Result Of Effect Of Treatments A, B, C, D &oth E On COD
3.1.5 Result Of Effect Of Treatments A,os Bes ,eo dnC lfy,.or Dany & E On Suspended Solids 31
3.1.6 Result Of Effect Of Treatmeectinotnw snpe urAr rpe,q Buir, C, D & E On Oils, Fats & Greases 32
3.1.7 Result Of Effect Of TrFeora itnysmripgeht nots A, B, C,D & E On Dissolved Sugars 33
33..11..89 RReessuulltt OOff EAfufteo c s t a Oo m n s f ep nB t l i oAfn cgFop OOnn E pcHla Oirvs eGr rAea Pseer Tiorda pO f 6 Days 3344
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3.1.10 Result Of Autosampling On Timeout Grease Trap 35
3.1.11 Result Of The Determination Of The Decrease In Total Suspended
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Solids By Biological Aerated Filter Treatment
4. DISCUSSION 37
4.1 Introduction 37
4.2 Industrial Effluent 37
4.2.1 Biological Filter Treatment 37
4.3 Effect of Non -Biological Treatment & Non-Aeration On The Waste
Water Quality Parameters 38
4.4 Effect Of Biological Aerated Filter On pH Over a 6 Day Period 38
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4.5 Effect Of Aeration Versus Non-Aeration On The Biological System 39
4.6 Filter Media System & Biofilm 39 I
4.7 Limitation Factors of Biological Aerated Filter Treatment In The
Grease Traps 40
4.8 Recommended Future Work 41
5.0 CONCLUSION 42
BIBLIOGRAPHY 43
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Figures
Figure 1.1 Schematic diagram of grease trap 8
Figure 1.2 Synthesis and energy production in biological oxidation of organic matter 14
Figure 1.3 Enzymatic hydrolysis and bacterial breakdown of organic residues 14
Figure 1.4 Formation of the biofilm 16
Figure 1.5 Representative picture ofb iofilter 17
Figure 3.1 Effect of treatments A, B, C,D & E on pH value 28
Figure 3.2 Effect oft reatments A, B, C,D & E on BOD 29
Figure 3.3 Effect oft reatments A, B, C,D & E on COD 30
Figure 3.4 Effect oft reatments A, B, C,D & E on Suspended Solids 31
Figure 3.5 Effect of treatmenys A, B, C,D & E on OFG 32
Figure 3.6 Effect of treatments A, B, C,D & E on Ref Index . 33
Figure 3.7 Effect ofB AF treatment on pH over a period of 6 days 34
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TTaabbllee 31..11 ER xeissutlitn gof e tnhvei reoffnemcte ontfa tlr leiactemneccetiinonntw gsnpe u rAr lrpiem,q uBiir,ts C ,D & E on pH value 298
Table 3.2 Result of the effect of trFeora itnysmripghet nots A, B, C,D & E on BOD 29
TTaabbllee 33..34 RReessuulltt ooff tthhee eeffff ee cc tt o n oo s e f nf t tt orrf eecoaapttmmeennttss AA,, BB,, CC,, DD && EE oonn CSuOspDe nded Solids 3301
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Table 3.5 Result oft he effect of treatments A, B, C,D & E on OFG 32
Table 3.6 Result of the effect oft reatments A, B, C,D & E on Ref. Index 33
Table 3.7 Result of the analysis oft he Eclairs grease trap 34
Table 3.8 Result oft he analysis of the Timeout grease trap 35
Table 3.9 Results of decrease on the total suspended solids present due to BAF 35
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Abbreviations
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Biological Aerated Filter (BAF)
Biochemical Oxygen Demand (BOD)
Chemical Oxygen Demand (COD)
Oils, Fats & Grease (OFG)
Environmental Protection Agency @PA)
Kilogrammes per day (kg/day)
Milligrammes per day (kglday)
"C (degrees Celsisus)
Treatment A : non-biological / non-aeration
Treatment B : aeration
Treatment C : biological concentrate / non-aeration
Treatment D : biological concentrate / aeration
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Treatment E : biological concentrate / biofilter / aeration er us
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1. Introduction
1.1 Introduction
This project was undertaken at Cadbury’s Ireland Ltd in Coolock, Dublin. Cadbury Ireland
Ltd is part of the multinational Cadbury Schweppes group which markets and distributes its
confectionery and beverages products in almost 200 countries worldwide. As a major global
group, Cadbury recognises their important responsibilities in caring for the local and global
environment. As stated in their environmental policy, Cadburys Schweppes ‘see sound and
responsible environmental management as an integral part to ensure that they minimise the
environmental impact of their activities on the world around us’.
1.2 Industrial Effluent e.
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Industrial effluents can be considered to be anyos elsi qeodnu lfy.oird a nwy aste product, discharged from a factory, or
idnidffuesrternyt wprhoicdhu citsi onno tp rreoccyecslseeds .b Tachke iwnatoset ctetihwoenw a npweutrr erpoerq rufkirr opmro tchees sv. aTrihoeu fso pordo cinedssuesst rvya irniecslu cdoenss sideverearball y as
the composition of the product willF oirn infysrlipughet noce the composition of the product will influence the
composition of the wastewa t e ro n (s eJ no t orf gceopnsen, 1988).
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If untreated wastewater is allowed to accumulate, the decomposition of the organic materials it
contains can lead to the production of large quantities of malodourous gases. The sewage
treatment process relies upon the processes of settlement of solids, and biological oxidation of the
remaining pollutant matter. The strength of effluents is based upon suspended solids present, and
biochemical oxygen demand, (BOD). (Jefferys)
1.2.1 Current Environmental Position
The food industry affects the environment through the discharge of wastewater to surface water
courses and sewers. The changes in legal and social obligations both nationally and within the
EC
are making it necessary for all food processing industries to adopt a more professional approach to
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wastewater mana-g ement. Cadburys are currently facing environmental challenges relating to the
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disposal of oils, fats and greases and the quality of the &water entering the river at various
outfalls.
Project 0b j ective:
In order to be consistent with cuurent local authority wastewater limits the objective of this project
is to monitor the effect of biological aerated treatment with a view to decreasing wastewater
parameters such as BOD, COD, SS and OFGs while maintaining a pH within the specification of
6- 10.
The only previous existing preliminary treatment present for oils, fats, and greases on site were
grease traps which work on the principle of flotation. There are nine such devices scattered around
the premises to remove the solids content which consists of fae.tty wastes fiom the effluent leaving
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the processing sites. Each system consists of three traps potohesr itioned in series. The system is an
effective and hygenic method of separating fat aosnesd eo dng lfyr.ore aanys e fiom wastewater flow. However the
idnidspuostsrayl. o Tf hthee n aucmcbuemr ualnadte cda opialc, iftayt so, fa lnadn edcgtifroienwl anlpesusrr rpehe qaruiverme baeinesn a rne doubcsetadc alen de nnveiwro nlamndefnitlal llloyc faotri otnhse tfhoaotd
meet environmental, social and econFoor minysriipcgh tr oequirements are increasingly difficult to find and so an
alternative method for the el i m io nn s a e nt t i oof nco pof oils, fats, and greases is required.
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GreaseTrap
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Is a system (undergrohd tank) designed to capture oil and greases on site fiom the waste exiting
the plant. Grease traps which work on the principle of floatation. In wastewater treatment,
floatation is principally used to remove suspended matter and to concentrate biological sludge.
Suspended material rise falls depending on whether its density is less or greater than that of
or
water. Once the particles have floated to the surface they can be collected by a skimming operation
by external contractor. (Environmental Engineering Science, 2000)
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