european water treatment code

t?A M eo y

Commission of the European Communities Diteciotaie Generai fot Science, Research ana Development Environment Research Programme

ADVANCED DESIGN AND OPERATION OF

MUNICIPAL WASTE WATER TREATMENT PLANTS

PILOT PLANT FLQW PI,

PRIMARY SETTLERS

AERATION TANK

OaomilUc L _ r ~ s ^ ^

Vccn/i T2 m :

SECONDARY ! : SETTLERS l

VimclaJO 5 m'

u*a *.C*

f Kr

0 * 4 j

MAIN DIFFERENCES BETWEEN BOTH SYSTEMS ABE : sue ol scccntary sell 11 recirculation capacity : ; ! ; , ' ;

AERATION TANKS AND SECONDARY SETTLER WERE THERMICALLY INSULATED FOR LOW TEMPERATURE EXPERIVENTS

Contract N EV4V0073E (A) L. Concha M. Henze

TECHNOLOGIES FOR ENVIRONMENTAL PROTECTION

REPORT 1 EUR 15030 EN JUNE 1992

COMMISSION OF THE EUROPEAN COMMUNITIES Directorate-General for Science, Research and Development

Environment Research Programme

CONTRACT NO. EV4V-0073-E (A) L. Concha M. Henze

ADVANCED DESIGN AND OPERATION OF MUNICIPAL WASTE WATER

TREATMENT PLANTS

Technologies for Environmental Protection Report 1

PARL EUROP. Biblioih.

N . C . ^ io^o

CI.

EUR 15030 EN JUNE 1992

Advanced Design and Operation of Municipal Waste Water Treatment Plants

Contract No. EV4V-0073-E(A)

Project coordinator: L. Concha Ente Vasco de la Energia (EVE) Edificio Albia 1 San Vincente. 8 - Pianta 14 48001 - Bilbao

Edited by: L. Concha, Ente Vasco de la Energia (EVE), Spain M. Henze, Technical University Lyngby, Denmark J. Busing, CEC, DG XII, D-l, Brussels, Belgium

ISBN 2-87263-085-6 Depot legal D 1992/0157/09

This is report No 1 in the Technologies for Environmental Protection Report Series of the Environmental R&D Programme of the Commission of the European Communities, Directorate-General for Science, Research and Development.

For more information concerning this series, please contact :

Mr. H. Ott CEC-DG XII/D-1 Rue de la Loi, 200 B-1040 Brussels

No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without indicating the above mentioned references.

Publication No EUR 15030 EN of the Commission of the European Communities, Dissemination of Scientific and Technical Knowledge Unit, Directorate-General Information Technologies and Industries, and Telecommunications, Luxembourg

ECSC-EEC-EAEC, Brussels-Luxembourg, 1993.

LEGAL NOTICE

Neither the Commission of the European Communities nor any person acting on behalf of the Commission is responsible for the use which might be made of the following information.

E. GUYOT SA, rue Ransfort 25, 1080 Brussels

Printed in Belgium

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FOREWORD

Research work desoribed in the report was aimed at optimizing design and operation of unified Sludge Age Control Technology (USCT) in order to enable aotivated sludge plants to treat a greater variety and strength of municipal and industrial waste waters than a conventionally designed and operated plant. The conventional and the new processes were studied in parallel, eaoh fed with about 85% domestic and 15% industrial waste water originating from major industrial sources located in the Galindo/Bilbao area. The present report is the first issue of a series of Technologies for Environmental Protection Reports supported under the EC Environment Programme of DGXII.

J. Busing, DGXII/D-1

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CONTENTS

SUMMARY AND CONCLUSIONS 5

INTRODUCTION 7

PILOT PLANT DESCRIPTION 10

2.1. Pumping of domestic sewage 14

22. Primary settling 14 23. Biological reactor 15 2.4. Secondary settling 16 2.5. Sludge recirculation 17 2.6. Incoming industrial waste reception 18 2.7. Means for homogenization, preparation and dosage of industrial wastes. 18

METHODOLOGY 19

3.1. Research schedule 19 32. List of sampling points and general sampling strategy 20 33. List of analyzed parameters 24 3.4. List of continuously measured parameters 27 3.5. Total number of samples and analysis 29 3.6. Scientific and technical team 30 3.7. Analytical methods 31

OPERATING STRATEGY 33

4.1. Control parameter: sludge age. 34 42. Control parameter: F/M ratio 38

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RESULTS 44

5.1. Operating conditions in intensive periods 46 52. Hydraulic data 47 53. Influent to Pilot plant 48 5.4. Metals in influent to pilot plant 49 5.5. Primary clarifiers effluents 50 5.6. Metals in primary clarifiers effluents 51 5.7. Final effluents 52 5.8. Metals in final effluents 53 5.9. Diurnal variations CONV system 54 5.10. Diurnal variations FMCT system 55 5.11. Activated sludge mass balance (1) 56 5.12. Activated sludge mass balance (2) 57 5.13. Sludge quality 58 5.14. Metals in primary sludge 59 5.15. Metals in activated sludge 60 5.16. Aeration parameters 61 5.17. Energy consumption 62 5.18. Sludge age calculation 63

MODELLING 64

6.1. Introduction 64 62. Concepts of models 64

6.2.1. Activated sludge model 64 622. Secondary clarifier model 66

63. CAB description 68 6.4. Model plant 69 6.5. Input data handling 70

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6.6. Operation conditions used for modelling 72 6.7. Modelling and analyzing 73

6.7.1. Notes on modelling 73 6.12. Some results from the modelling of the pilot plant 74 6.73. Calibration of constants in the model 77

6.8. Conclusion 80 6.9. List of symbols 81

7. DISCUSSION OF RESULTS 83

7.1. Primary settling 83 7.2. Activated sludge process 86

7.2.1. Nitrification 86 122. Activated sludge quality 90 123. Settling velocity 96 12.4. Effluent quality 100 12.5. Yield coefficient 106 7.2.6. Energy consumption 110

13. Secondary settling 110 7.4. Heavy metals 118 7.5. General wastewater characteristics 119

8. CONCLUSIONS 120

8.1. General conclusions 120 82. New system 122 S3. Modelling 123

9. LIST OF SYMBOLS 124

10. REFERENCES 126

ANNEXES

1. Drawing and photographs of the Pilot plant and Laboratory 129 2. Description of the analytical methods 139

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0. SUMMARY AND CONCLUSIONS

Although there is a vast number of wastewater treatment plants operating throughout the world, it is a well-known fact that many of them don't meet the standards they were designed for, particularly in plants treating mixed wastewaters (domestic and industrial). The problems usually affecting the plants are influenced by the following basic factors: sludge acclimatisation capacity to industrial wastes, flexibility and controlability of the process, secondary settling performance and aeration capacity.

Knowing these, it was the purpose of the research to investigate a new process called FMCT process (FMCT: food mass control technology) that is a new modification of the activated sludge system. FMCT system includes a big settling tank which allows for storage of biomass and control of F/M-ratio under varying load conditions. The new process was supposed to provide the following advantages over the conventional system:

Better adjustment of biomass to instantaneous needs.

Reduction of aeration tank volume using concentrations of 5-8 g MLSS/1.

Reduction of energy consumption in aeration tanks.

Better quality of treated wastewaters.

Lower volume of excess sludge.

Lower probability of bulking problems.

A pilot plant study has been carried out in Galindo (Spain) primary treatment full scale plant, treating mixed wastewaters (domestic and industrial) in two parallel lines, one working with the CONV system and the other with FMCT system.

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Seven intensive study periods were carried out covering a range of temperatures: 8" C to 2? C, and F/M-ratios: 0.15-0.60 (kg BOD/kg VSS.day).

A new mathematical model based on the IAWPRC activated sludge model no. 1 was developped for the new system giving special attention to model the secondary settler.

The effluent quality found in both systems is well below the proposed EEC standards. The soluble inert COD in the effluent is approximately 30-40 mg/1. Increasing F/M-ratio increases soluble COD in the effluent having decreasing temperature a similar effect.

Nitrification rates were low due to low pH and low alkalinity. Calculated nitrification rates with IAWPRC activated sludge model no. 1 for pH-(7-7.5) were normal so no additional inhibitory effects on nitrification was detected.

The yield is highly influenced by temperatures and F/M-ratio. For similar F/M-ratio the yield at ffC was approximately twice the yield at 23 C.

The new system has proved to allow for better adjustment of biomass to instantaneous needs due to storage of large amounts of biomass in the big clarifier. Other advantages observed were: less occurrence of bulking and foaming problems, excess sludge volume lower due to higher concentrations reached in secondary settler and sludge produced was more stabilized with lower percentage of volatile suspended solids.

The mathematical model has shown to be a valuable tool for interpretation of experimental results and for description of the actual settler performance and the performance of the biological reactors.

INTRODUCTION

Bilbao is a coastal city in northern Spain which has about 1,000,000 habitants in its drainage area. Sizable industry discharges its wastewaters to a severely polluted estuary as well.

The "Consorcio de Aguas de Bilbao, Abastecimiento y Saneamiento" (CAGB), is a public company owned by 24 municipalities.

Now the sewerage scheme in Bilbao is being developed and the wastewater treatment plant of Galindo is in operation providing primary treatment to about 150,000 p.e. since July 1990.

The next stage in the scheme will be the construction of the biological treatment in Galindo wastewater treatment plant as well as the construction of new sewers.

For that purpose a pilot plant was built in 1981 in order to investigate the performance of biological treatment with the Bilbao wastewater. During the period 1981-1987 several investigations were conducted in the pilot plant; resulting in great experience to a Consorcio team that becomes specialised in biological wastewater treatment processes as well as analytical methods.

Although there is a vast number of wastewater treatment plants operating throughout the world, it is a well-known fact that many of them don't meet the standards they were designed for. The problems usually affecting these plants are influenced by five basic factors: - sludge acclimatization capacity to industrial wastes; - flexibility of the process; - controllability of the process; - secondary settling; - aeration capacity.

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The effects of deficiencies in these five areas produce the typical problems such

as:

- sludge bulking and flotation; - scum production; - inhibition caused by toxic agents; - high consumption of electricity; - poor performance in the treatment

Knowing these, it was the purpose of the Consorcio to investigate new designs and operational strategies for biological treatment of mixed (domestic and industrial) wastewaters. The new process to investigate was called FMCT process (FMCT: Food to Microorganisms Control Technology). FMCT system includes a large final settling tank which allows storage of biomass and control of F/M ratio under varying load conditions. The new process was supposed to provide the following advantages over the conventional system:

1. Better adjustment of biomass to the instantaneous needs. 2. Reduction of aeration tank volume using concentrations of 5 to 8 g/1 of mixed

liquor suspended solids. 3. Reduction of energy consumption in aeration tanks. 4. Better quality of treated wastewaters. 5. Lower volume of excess sludge. 6. More stable sludge with a lower proportion of volatile suspended solids. 7. Better sedimentation characteristics of the sludge with lower probability of

bulking problems.

To investigate the new process the pilot plant was modified having two parallel lines one working with the Conventional (CONV) system and the other with the FMCT system. The pilot plant was provided with cooling systems to carry out experiments at low temperatures (8C).

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The investigation project was presented in the DG XII by the Consorcio de Aguas de Bilbao and EVE (Ente Vasco de la Energia). Prof. Mogens Henze from the Technical University of Denmark was in charge of developing a mathematical model for the new system giving special attention to model the secondary clarifier. During the investigation Prof. Peter Grau from the Prague Institute of Chemical Technology became involved in the project giving valuable advice in activated sludge population dynamics.

The pilot plant was installed in the Galindo wastewater treatment plant were it was fed with mixed wastewaters (domestic and industrial). The experiments have being performed during two years and finished in March 1991.

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2. PILOT PLANT DESCRIPTION

As described in the previous chapter the plant is equipped with two lines or processes which can be used in parallel. One of the lines is the conventional completely stirred activated sludge tank followed by a traditionally sized final clarifier, so called CONVentional process (CONV), while the other system has much larger final clarifier. The system is called "Food to Microorganisms ratio Control Technology" (FMCT). A flow diagram of the pilot plant is shown in Figure 2.1.

The sewage treatment lines consist of the following:

- pumping of domestic sewage; - mixing, homogenization and distribution to the two lines of both domestic and

industrial sewage; - primary settling; - biological reactor for activated sludge; - secondary settling; - sludge recirculation.

For the sake of completeness and for industrial waste composition purposes, the following is available:

- incoming industrial waste storage tanks; - means for homogenization, preparation and dosage of industrial wastes.

A detailed drawing of the pilot plant is included in Annex 1.

of secondary settler recirculation capacity

AERATION TANKS AND SECONDARY SETTLER WERE THEfMICAU.Y INSULATED FOB LOW TEMPERATURE EXPERIMENTS

t=MC'r^ 2 - l imali

at^Mg'-'- ::...; / ' f t B g a i a s g s B B

12-

Fig. 2.2. GENERAL VIEW OF PILOT PLANT

Fig. 2.3. INDUSTRIAL WASTES STORAGE TANKS

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Fig. 2.4. AERATION TANK CONTROL METERS

aa _ .

**' ' : : * I

wrosi i TU!

Fig. 2.5. PILOT CONTROL ROOM

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2.1. Pumping of domestic sewage

In a well two submersible pumps are placed, one as a spare pump, of the

displacement type and protected by a bar screen for solids, hand-operated but

designed for self-cleaning.

The flow rate of each pump is 15 m3/h, the impulse pipe is made of

polypropylene, 1,000 m in length and 2.1/2" in diameter and flows into a

homogenization chamber where an agitator mixes domestic and industrial wastes

adequately. Distribution to each line takes place through two weirs. The flow rate

to each unit is controlled.

Pumping characteristics

No. of pumps 2

Unit flow rate 15 m3/h

Power 5.5 kW

Type of runner Displacement

Impulse piping 2.1/2" dia. Polypropylene

2.2. Primary settling

Each sewage treatment line is equipped with a primary settler 2.2 m in diameter,

made of steel plates and protected with epoxy paint.

The sewage flows in through a pipe into a central distribution well; it flows out by

gravity through a V-notched weir.

The bottom- is conical shaped, without scrapers, and the sludge is removed by

means of an automatic, programmed pneumatic valve.

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Primary settling characteristics

Design flow rate 3 m3/h each settler Diameter 2.2 m Overflow rate 0.79 m/h Total volume 12 m3

2.3. Biological reactor

Each line is equipped with a 18 m3 tank, where biological reactions take place. Supply of oxygen is made by means of two blowers (one for each line), which inject air into the reactor through fine-bubble ceramic diffusers.

Cooling coils are inside the reactors in order to enable carrying out tests at temperatures lower than ambient temperature. The reactors are, therefore, thermally insulated.

To prevent solids from settling when the air flow is low, each reactor is fitted with a submerged propeller.

In each reactor tank, the pH, dissolved oxygen and temperature are continuously controlled, the last two parameters acting automatically on the supply of air and on the refrigerating equipment.

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Biological reactor characteristics

Volume Material Design retention time Air injection flow Thermal insulation Temperature reduction

18 m3 Steel plates, protected by epoxy paint 6h 125 m3/h each blower Expanded polystyrene Vaporization coils

2.4. Secondary settling

The conventional line is equipped with a secondary settler 2.2 m in diameter, made of steel plates; the FMCT line has a 4 m diameter settler, also made of steel plates.

In both settlers sewage flows in through a central baffle well and overflows through a V-notched weir.

The bottom is of conical shape; the 4 meter diameter settler was equipped with a bottom scraper.

For low-temperature operation both settlers are insulated by means of a layer of expanded polystyrene.

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Secondary settler characteristics

Conventional Line FMCT Line

Diameter m Overflow rate m/h Aplied solids flux kg/(m2.h) Thermal insulation Total volume m3

2.2 4 0.79 0239

4.14 535 Expanded polystyrene 12 m3 405

2.5. Sludge recirculation

The CONV line is equipped with two Mono rype pumps, capable of a variable flow rate by means of frequency converters operated from the central panel. The FMCT line has three pumps with the same features, whereby the re-circulating capacity is increased.

There exists a continuous control on the flow of sludge which is being re-circulated, with a direct reading on the panel.

Sludge recirculation characteristics

Conventional Line FMCT Line

No. of pumps 2 Unit flow rate 0.6-4 m3/h Recirculation rate 0.7-3 m3/h Flow rate variation Frequency converter

3 l-6m3/h 2-12 m3/h

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2.6. Incoming industrial wastewater reception

There is a set of 5 m3 m cylindrical tanks, made of glass-fibre reinforced polyester, for the reception of concentrated industrial wastewaters.

Each tank contains a vertical mixer driven by a slow-speed .motor for the homogenization of wastes received by tank trucks at variable intervals.

Each tank is fitted with a bottom-discharging valve through which a part of each type of waste is removed to the 20 m3 joint preparation tank.

2.7. Homogenization. preparation and dosage of industrial wastes

There is a homogenization and preparation tank where the various types of industrial wastes are brought together, mixed and diluted. After preparation, the whole mixture is transferred into another storage tank, whence it is finally dosed, by means of a variable flow pumping unit, into the general inlet trough where it is mixed with domestic sewage. Both the preparation thank and the industrial waste dosage tank have a 20 m3 capacity.

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3. METHODOLOGY

In the course of the research work, seven intensive study periods were carried out under different operating conditions of the pilot plant.

In Periods 1 and 2 temperatures were maintained in the 14C region (Winter).

In Period 3 the temperature was about 20C (Spring).

In Periods 4 and 5 the temperature was kept in the 23C region (Summer).

Finally, in Periods 6 and 7 (Winter) the cooling systems installed in the aeration tanks were used, the temperature being kept at about 8C. Ambient temperature during the latter periods was 10-12C.

At each temperature two different conditions of F/M ratio were tested.

In between the various intensive periods there were transition periods in which the pilot plant was stabilized to the specific operating conditions which were subsequently maintained during the next intensive period.

3.1. Research schedule

Period 1: 16-19 Jan. '90 Temperature approx. 13C CONV. Line F/M = 0.376 FMCT Line F/M = 0.275

Period 2: 26 Feb-26 Mar '90 Temperature approx. 16C CONV. Line F/M = 0.405 FMCT Line F/M = 0.174

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Period 3: 16-30 May. '90 Temperature approx. 19.5C CONV. Line F/M = 0.845 FMCT Line F/M = 0.22

Period 4: 9-24 Jul '90 Temperature approx. 23C CONV. Line F/M = 0205 FMCT Line F/M = 0.162

Period 5: 20 Aug-3 Sep '90 Temperature approx. 23C CONV. Une F/M = 0.4 FMCT Line F/M = 0.282

Period 6: 14-31 Jan '91 Temperature approx. 8C CONV. Line F/M = 0.231 FMCT Line F/M = 0.207

Period 7: 18 Feb-8 Mar '91 Temperature approx. 8C CONV. y ne F/M = 0.579 FMCT Line F/M = 0.429

3.2. List of sampling points and general sampling strategy

For identification of the sampling points, the following codes have been used:

First character Identifies the treatment line.

C: CONV U: FMCT

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Other characters: Identify the location of the sampling point.

TJWO: domestic sewage IWO: industrial waste SPO: influent into plant - domestic and industrial mixture

SPI SP2; SP3 SP4: SP5 SP6: SP7:

effluent from primary settling contents of aeration tank effluent from aeration tank effluent from secondary settling re-circulated sludge from secondary settling sludge from mixed liquor sludge removed from primary settling

Sampling points scheme is shown in figure 3.1 Types of samples taken are as follows:

Type 1: composite - 24 hours (500 ml samples taken hourly) Type 5: grab taken at 9:00 hrs Type 6: grab taken at 17:00 hrs Type 7: grab taken at 01:00 hrs

Both during the intensive and transition periods, the following samples were taken on a daily basis:

1) SPO: composite sample from 24 hrs, influent to pilot plant.

2) CSP1 and USP1: composite sample from 24 hrs, effluents from the primary settling.

3) CSP4 and USP4: composite sample from 24 hrs, final effluents. 4) CSP2 and USP2: 3 grab samples daily (9hrs, 17 hrs and 01 hrs),

mixed liquors.

FIG. 3.1: SAMPUNG POINTS PILOT PLANT

MIXING TANK

INDUSTRIAL WASTE

PI L^^_^ DOMESTIC WASTE

AER AVON

TANK

RECIRCULACtON

RECIRCULAVON

DOSING TANK INDUSTRIAL WASTE

LINE CONV

- EFFLUENT

WASTED SLUDGE

SP.) ...LINE FMCT

EFFLUENT

WASTED SLUDGE

IW2 1 f IW3

MIXING TANK FOR INDUSTRIAL WASTE

IW5 J I IW6

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5) CSP5 and USP5: 3 samples daily (9 hrs, 17 hrs and 01 hrs) of re-circulated sludge.

At the end of each intensive period, additional samples were taken:

6) CSP7 and USP7: Grab sample of primary sludge at 9 hrs.

Sampling was done manually, by the plant operators in all cases, except for variability studies, when samples were taken by automatic samplers.

Upon completion of the last two intensive periods, a special sampling was made to define the varying conditions in the pilot plant. This sampling was carried out by taking samples every 2 hours for a 24 hours period, each individual sample being independently analyzed.

The analyzed sampling points were as follows:

CSP1: effluent from primary settling, CONV line USP1: effluent from primary settling, FCMT line CSP4: effluent from secondary settling, CONV line USP4: effluent from secondary settling, FCMT line CSP3: effluent from aeration tank, CONV line USP3: effluent from aeration tank, FCMT line CSP5: re-circulated sludge, CONV line USPS: re-circulated sludge, FCMT line

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3.3. List of analyzed parameters

The following groups are distinguished:

Group 1. General parameters

TSS Total Suspended Solids (mg/L)

VSS Volatile Suspended Solids (mg/L) CODT Total Oxygen Chemical Demand (mg 02/L) CODS Soluble Oxygen Chemical Demand (mg 02/L) BODT Total Oxygen Biochemical Demand (5 days) (mg 02/L) BODS Soluble Oxygen Biochemical Demand (5 days) (mg 02/L) TKNT Kjeldahl Total Nitrogen (mg/L) TKNS Kjeldahl Soluble Nitrogen (mg/L) NH4-N Ammonia Nitrogen (mg/L) N03-N Nitrate Nitrogen (m'g/L) ALCALT Total Alkalinity (mmol HC03-/L) P TOT Total Phosphorus (mg/L) P04-P Dissolved Orthophosphate P (mg/L) SULF T Total Sulfides (mg/L) CL" Chlorides (mg/L) O & G Oils and Greases (mg/L)

Group 2. Special parameters

Phenols Phenols (mg/L) Deterg. Anionic Detergents (mg/L) CN-T Total Cyanides (mg/L) Ca T Total Calcium (mg/L) Mg T Total Magnesium (mg/L)

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Cd T Total Cadmium (mg/L) Cr T Total Chromium (mg/L) Cu T Total Copper (mg/L) Ni T Total Nickel (mg/L) Pb T Total Lead (mg/L) Zn T Total Zinc (mg/L) As T Total Arsenic (mg/L) Hg T Total Mercury (mg/L)

Group 3. Specific analyses of sludge

TSS Total Suspended Solids (mg/L) VSS Volatile Suspended Solids (mg/L) SVI Sludge Volume Index (ml/g) ESP. GRAV. Specific Gravity ISV Initial Settling velocity (cm/min) SV Volume Settled Within 30 min (ml/L) OUR Oxygen uptake Rate (mg O^L. h) SOUR Specific Oxygen Uptake Rate (mg 02/g.h) H. BLANKET Sludge Blanket Height (m) MICROSCOPIC Examination

Analyses Schedule During Intensive Periods

On sewage samples: Type 1 (composite from 24 hrs)

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1 1 Frequency

1 Daily

| Three times | per week

SPO TSS VSS P04-P P TOT

0 & G Phenols Deterg. Sulfides Cyanides

i CSP1 | CODT CODS Al cal Cl Ca Mg Cu Cr

USPl BODT BODS

Fe Zn Ni Cd

CSP4 TKNT TKNS

Pb Mn Hg

USP4 | 1 NH4-NI

N03-NI

On sludge samples: Types 5, 6 and 7 (grab samples, taken at 9, 15 and 01 hrs)

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I SP2-5 SP2-6SP2-7SP5-5SP5-6SP5-7 SP7 1 i i i i i i | TSS VSS | |

| | SV Blanket H | | | i i i i i I I I - i l 1 Daily Sp. Gr.j | | | | ISV | | | | | OUR | | |

Twice Micro. |per Week | Anal j j

| | | |TSS VSS| Only Once,Ca Mg Ca Mg at the EndCu Cr Cu Cr of each Fe Ni Fe Ni Intensive Zn Cd| Zn Cd| Period Pb Mn Hg Pb Mn Hg

During transition periods

During the transition periods the same analysis with the same frequency were carried out as during the intensive periods, except for the sewage samples, were the following parameters were omitted: CODs, BODg, TKNS and P TOT. During the transition periods no samples were taken in SP7.

3.4. List of parameters measured in the plant on a continuous basis

All continuous measurement signals were received at a data acquisition unit connected to an IBM PC computer, where they were processed by means of the software Labtech. Notebook, the configuration of which enabled the data

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to be instantaneously transmitted from each meter to the printer every 15 minutes; thus, a daily printout with 96 entries was produced. The data printed every 15 minutes; represent the average value of all signals received during such a period of time. Summary printouts were also produced daily, listing the maximum, average and minimum values for each meter, as well as the total values. Parameters measured on a continuous basis are as shown below:

Instantaneous Measurements

1. Flow Rates

FI-1 Domestic sewage Influent FI-2 Industrial influent FI-3 Influent to the CONV line FI-3' Influent to the FMCT line FI-4 Sludge recirculation - CONV line FI-4' Sludge recirculation - FMCT line FI-5 Air to aeration tank - CONV line FI-5' Air to aeration tank - FMCT line

2. Temperatures

TI-1 Mixing tank for domestic sewage and industrial waste TI-2 Mixed liquor - CONV line TI-2' Mixed liquor - FMCT line TI-3 Secondary settler - CONV line TI-3' Secondary settler - FMCT line

3. pH

PHI-1 Mixing tank for domestic sewage and industrial waste pHI-2 Mixed liquor - CONV line pHI-2 Mixed liquor - FMCT line pHI-3 Secondary settler - CONV line pHI-3' Secondary settler - FMCT line

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4. Dissolved Oxygen

OIC-1 Mixed liquor - CONV line OIC-1' Mixed liquor - FMCT line

Totalized measurements

1. Flow Rates

FQ-1 Domestic sewage influent FQ-2 Industrial influent FQ-3 Influent to the CONV line FQ-3' Influent to the FMCT line FQ-4 Sludge recirculation - CONV line FQ-4' Sludge recirculation - FMCT line FQ-5 Air to aeration tank - CONV line FQ-S' Air to aeration tank - FMCT line

2. Power Input

Ul Blowers - CONV line U2 Recirculation pumps - CONV line U3 Blowers - FMCT line U4 Recirculation pumps - FMCT line US Recirculation pumps - FMCT line

3.5. Total number of samples and analysis

Research work covered a total of 610 days, split in 489 days of transition periods and 121 days of intensive periods. The number of samples processed during the transition periods is estimated at 8,313, on which 55,743 parame-ters were analyzed; during the intensive periods some 2,071 samples were taken and a total of 16,397 parameters analyzed.

Therefore, the total number of samples taken during the investigation was 10,384, on which 72,140 parameters were analyzed.

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3.6. Scientific and technical team

Miguel Lueje (CAGB - Mechanical Engineer) Alejandro de la Sota (CAGB - Biologist) Alberto Gmez (CAGB - Assistant Mechanical Engineer) Prof. Peter Grau (Scientific Consultant, President of IAWPRC) Prof. Mogens Henze (Technical university of Denmark, Modelling Expert) Ren Dupont (Technical University of Denmark, Modelling Expert)

Analytical Control

Karmele Zaballa (Biologist) Juan M' Cenigaonaindia (Chemist) Cristina Arrieta (Chemist) Jos Antonio Gonzlez (Chemical Technical Engineer) Itziar Unzueta (Biologist) Roberto Colino (Biologist) Ma Jesus Citores (Chemist) Marian Bilbao (Chemical Technical Engineer) Itziar Aretxabala (Chemical Technical Engineer) Pilot Plant Operation

Luis Angel Bilbao, Coordinator (Merchant Navy Chief Engineer) Ricardo Gmez (Electronics Technician) Rafael Lpez Heredia (Electronics Technician) Antonio Malave (Electrical Technician) Vicente Carro (Mechanical Technician) An tol in Trancho (Electronics Technician) Francisco Gutirrez (Electrical Technician) Esteban Garcfa (Electronics Technician) Iaki Zorrilla (Energetic Efficiency Technician)

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3.7. Analytical Methods

All analytical methods employed conform to "Standard Methods for Sewage Analysis", 17th Edition, 1989. The analytical methods used are listed hereunder.

3.7.1. General Parameters

TEMPERATURE pH DISSOLVED OXYGEN TOTAL SOLIDS TSS

VSS CODT

CODs BODT

BODs TKNT TKNS

NH4-N NO3-N ALKALINITY PTOTAL P04-P SULPHATES TOTAL SULPHIDES

CHLORIDES OILS & GREASES

Meter installed in the plant Meter installed in the plant Meter installed in the plant Evaporation and drying at 105C. Gravimetry Filtering through glass fibre. Drying at 105 C. Gravimetry Filtering. Ignition at 550C. Gravimetry Open reflux method. Oxidation by potassium dichromate for two hours. Membrane filtering. Two hours of open reflux Dilution method. Dissolved oxygen readings through probe Membrane filtering. Dilution method Acid digestion. Distillation and ammonia analysis. Membrane filtering and application of the above-named method Nessler colorimetrie method Chromotropic acid method Neutralization at Ph = 3.7 Acid digestion, orthophosphates analysis Vanadate-Molybdate method. Precipitation with barium salts. Gravimetry Precipitation. Filtering and titration with sodium thiosulphate Titration with silver nitrate Extraction by freon. Evaporation and gravimetry.

3.7.2. Special Parameters

PHENOLS Distillation and colorimetry of distillate with 4-aminoan tipyrine. Prior extraction with chloroform.

- 32

ANIONIC DET. TOTAL CYANIDES

TOTAL METALS

Standard LAS. Colorimetry with methylene blue. Distillation in acid medium. Selective electrode method Digestion by nitric acid. Analysis of metals by means of atomic absorption spectrophotometry.

3.7.3. Sludge Analysis

TSS

VSS SET. VOLUME SPEC. GRAV. ISV OUR

BLANKET HEIGHT

MICR. ANALYSIS

Filtration through glass fibre. Drying at 105C. Gravimetry. Filtration. Ignition at 550C. Gravimetry 30-minute settling in a 1-litre cylinder. Gravimetry Settling curve in a 2-litre graduated cylinder Probe measurement of the oxygen decay rate in a BOD bottle Height in meter from the bottom of the settling tank to the interphase between the settled sludge and the supernatant. Observation of sludge under the microscope. GRAM and NEISSER staining.

- 3 3 -

4. OPERATING STRATEGY

The plant has been treating a mixture of domestic sewage and industrial waste of the following constant ratio:

85% by volume - domestic 15% by volume - industrial

The industrial waste was prepared from concentrated pickling liquors. The final mixture had a concentration of approx. 20 ppm iron. Iron was the component with the highest concentration in the industrial waste that was handled.

Pumping facilities for the domestic sewage were located in a municipal collector at Sestao, from August 1989 till June 1990. Pumping was continuous from 06 hrs to 22 hrs; there were conditions of intermittent pumping during the night due to the low flow rate of the collector, aggravated by the drought and the water supply restrictions that prevailed in the district during that time.

From June 1990 till the completion of the Project, the pumping facilities were located at the Galindo Treatment plant, pumping being constant 24 hours a day ever since.

Control and operation of the plant was carried out, throughout the project, by the responsible technical personnel, 24 hours per day, 7 days per week.

The start-up of the pilot plant, prior to the formation of biomass in the aeration tanks, was based on domestic sewage. During that time, operating conditions in both lines were maintained as follows: 3 m3/h influent rate, 100% recirculation and dissolved oxygen levels of 2.5 mg/L.

- 3 4 -

Once sufficiently high concentrations of MLSS were reached, the acclimatization phase for industrial waste was initiated. Industrial waste was prepared from pickling liquors with high acidity and metal concentration (HCl-Fe and H2S04-Cu-Ni).

This mixture was diluted with clean water and mixed prior to entering the plant, with no previous neutralization. The concentration was increased by 10% daily, until 100% was dosed in ten days time.

Once 100% of industrial waste was reached in the mixture to be treated, a considerable deterioration of the effluent was observed and it was, therefore, decided to neutralize the industrial waste at Ph = 7 prior to the treatment. The pre neutralization was effected with NaOH.

Influents treated in each line were:

2.5 m3/h Domestic sewage 0.5 m3/h Industrial waste

Total = 3.0m3/h Mixture

From that moment on, the operating strategy can be divided into two parts, depending on the fundamental parameter of the process control selected:

Control Parameter: Sludge Age (9x) Control Parameter: Mass Load ratio (F/M)

4.1. Control Parameter ; Sludge Age (8x1 Operation criteria for periods 1, 2 and 3. As operating conditions we considered: dissolved oxygen, the recirculation rates and wasting rates.

- 3 5 -

4.1.1. Conventional line

Dissolved Oxygen

The D.O. concentration in the aeration tank was kept at a preset value, 1.5 mg/L, by means of an oxygen controller which receives a signal from a meter of the electrode probe type which, depending on the set point, actuates a speed variator which regulates the blowers, which respond to changes in the dissolved oxygen. The blowers increase or decrease the air supply to the aeration tank.

Recirculation Rate

Departing from the result of the 30-min settling test, the recirculation rate to be applied was calculated as follows:

Qr SV x 100 (4.1)

Qi 1000 - SV

where: Qr Recirculation flow Qi Influent flow SV Settled volume after 30 minutes.

Figure 4.1 can be used to calculate the recirculation rate as a function of the settled volume.

Wasting rate

When the sludge age established in each case is known, the wasting rate needed to maintain the sludge age constant is calculated as follows:

Fig.4.1.Chart for calculation of recycle flow as a function of settled volume test.

Recycle (low (%)

GO O)

150 200 250 300 350 400 450 500 Settled volume (SV ml/L)

37-

Qw =

where: Qw

Va

Gx

SSe

Qi

Va SSe. Qi v innn i A 'M

x MLSS

Wasted flow (l/d)

Volume of aeration tank (m3)

Sludge age (d)

Total suspended solids in effluent (kg/m3)

Influent flow (m3/d)

MLSS Total suspended solids in mixed liquor (kg/m3)

Wasting was carried out intermittently from the mixed liquor.

Another factor which was taken into account when carrying out the recirculation rate and wasting operations was the height of the sludge blanket in the secondary settling tank which, occasionally, due to bad settling characteristics of the sludge, rose to the extent that it caused loss of solids into the effluent. To preserve the characteristics of the effluent, the option was taken to increase the rate of recirculation by an additional 50% for two hours, with a maximum limit of 4.5 m3/h, and to waste 1 m3 of mixed liquor.

4.1.2. FMCTLine

Dissolved Oxygen

D.O. in the aeration tank was controlled automatically in the same way as in the conventional line and kept at a level of 2.5 mg/1.

- 3 8 -

Recirculation rate

Initially, the recirculation rate was adjusted three times per day, calculations being made according to the above formula (4.1). Later, recirculations in the 40 - 60% range were effected and, finally, recirculation rate charts were used, calculated as a function of the variation in the total organic load. Adjustment took place every hour.

One of the charts used is shown in Figure 4.2.

Wasting rate

Wasting was taken from the mixed liquor three times a day, at 8 h intervals, calculated as per formula (4.2). Each wasting was 1/3 of the total daily waste. To facilitate calculations, individual charts for each sludge age were designed, wherein the wasting rate is given as a function of the total suspended solids in the effluent and the total suspended solids in the mixed liquor.

One example is shown in Figure 4.3

42. Control parameter : Mass load ratio (F/M

It was the operating criteria during periods 4, 5, 6 and 7. Control was the same for both lines. The operating parameters considered in this case are: dissolved oxygen, influent flow rate, recirculation rate and sludge wasting.

Fig.4.2.Recycle flow curve used in FMCT line for periods 2 and 3.The curve follows the CODi variation in 24 h.

00

8 0 -

6 0 -

4 0 -

2 0 -

o -

Reoycle

1

\

i

Flow (%)

i v \

.

......

........

1

1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hours

Fig.4.3.Chart for calculation of wasting flow as a function of MLSS and TSSe for 0a-2O days.

300

250

2 0 0 -

1 5 0 -

1 0 0 -

5 0 -

Qw (L/8 hours)

-

-+-- * -

- B -

- K -

- e --A

- S -

SSe-10ppm

SSe20ppm

SSe-30ppm

SSe-40ppm

SSe-50ppm

SSe-60ppm

SSe-70ppm

SSe-80ppm

o

-41 -

Dissolved Oxygen

The set point for CONV line = 1.5 mg/1, FMCT line = 2.5 mg/1, being established, this was maintained automatically as described above. Higher DO in FMCT line was selected to provide sufficient concentration gradient of oxygen for the higher MLSS.

Influent Flow Rate

After establishing the F/M ratio to be maintained during the period under consideration, the influent flow rate was calculated daily, depending on the volatile suspended solids 'in the mixed liquor and the chemical oxygen demand of the influent, by applying the following formula:

F/M . MLVSS . Va Qi = (4.3)

BOD

BOD = 0.44 COD

where: Qi Influent flow (m3/d) BOD Biochemical oxygen Demand (kg/m3) MLVSS Volatile suspended solids in mixed liquor (kg/m3) Va Aeration tank volume (m3) COD Chemical Oxygen Demand (kg/m3)

This is displayed in Fig. 4.4.

Recirculation rate

This was adjusted as high as necessary, to prevent sludge from floating in the secondary settling tank as a result of de-nitrification. During low-temperature periods, when these flotation problems did not occur, the recirculation rates were smaller, about 50%.

Fig.4.4.Chart for calculation of influent flow as a function of MLVSS and CODi for F/M 0.5

I, 1 D

1 4 -

1 2 -

1 0 -

8 -

6 -

4 -

2 -

o -

Ql

-

(m3/h) I

* COD-300 mg/l - 4 - COD-350 mg/l - * - COD-400 mg/l - B - COD-450 mg/l - * - COD-500 mg/l

j ^ " * ^ ^ ^ " * " " ^

- 4 3 -

Wasting rate

Wasting were carried out depending on the height of the sludge blanket in the secondary settler.

During high-temperature periods (4 and 5), limits of 3.2 m for the CONV line and 3.7 m for the FMCT line were established.

Considering that the concentration of total suspended solids in the effluent was too high with respect to good sludge settling characteristics during high-temperature periods and on the assumption that this might be due to excessive blanket height, the decision was made to decrease it; for low-temperature periods (6 and 7) the limits were set at 2 m. for the CONV line and 3.5 m. for the FMCT line.

-44 -

RESULTS

In this chapter are included all the average results for each intensive period. This results are discussed later in chapter 7.

45

TABLE 5.1. OPERATING CONDITIONS IN INTENSIVE PERIODS

TABLE 5.2. HYDRAULIC DATA

TABLE 5.3. INFLUENT TO PILOT PLANT (Domestic & Industrial)

TABLE 5.4. METALS IN INFLUENT TO PILOT PLANT (Domestic & Industrial)

TABLE 5.5. PRIMARY CLARIFIERS EFFLUENT CSP1/USP1

TABLE 5.6. METALS IN PRIMARY CLARIFIERS EFFLUENT CSP1/USP1

TABLE 5.7. FINAL EFFLUENTS CSP4/USP4

TABLE 5.8. METALS IN FINAL EFFLUENTS CSP4/USP4

TABLE 5.9. DIURNAL VARIATIONS CONVENTIONAL SYSTEM

TABLE 5.10. DIURNAL VARIATIONS FMCT SYSTEM

TABLE 5.11. ACTIVATED SLUDGE MASS BALANCE (1)

TABLE 5.12. ACTIVATED SLUDGE MASS BALANCE (2)

TABLE 5.13. SLUDGE QUALITY

TABLE 5.14. METALS IN PRIMARY SLUDGE CSP7/USP7

TABLE 5.15. METALS IN ACTIVATED SLUDGE CSP2/USP2

TABLE 5.16. AERATION PARAMETERS

TABLE 5.17. ENERGY CONSUMPTION

TABLE 5.18. SLUDGE AGE CALCULATION

TABLE 5.1: OPERATING CONDITIONS IN INTENSIVE PERIODS

PERIOD DATE

FA< (kgBOtVkgMLVSS.day)

Temperature (deg C)

Primary aettllng

Influent flow (Ql) (m'/h)

Recycle flow (Or) (m'/h)

D.O. (mg/l)

Blanket level (m)

pH

Total sludge age (daya)

MLVSS (mo/I)

Recycla VSS (mg/n

U (KgBOO/kgVSS.day) (1)

Sludge wasted (kgVSS/day) (2)

Effluent sludge (kgVSS/day) (3)

Sludge wasted and lost (4) (KgVSS/day)

MIVSS/MLSS

1 16-29 Jan 90

CONV

0,376

12,9

Yes

2.53

1.91

0,97

2.1

7,4

9,6

2642

6912

0.318

2.036

4.752

6.767

0.83

FMCT

0.275

13.2

Yes

2.54

1.54

2.65

1.4

6.8

11.5

3630

10621

0.254

0.17

1.987

2,157

0.B1

2 26Feb-26Mar 90

CONV

0,405

15.6

Yes

2.07

1.59

1.6

2,5

7.4

6.7

2194

5062

0.36

6.972

1.63

8.602

0.80

FMCT

0.174

16.4

Yes

2

1.56

2.07

3.1

7,3

47.4

5091

11450

0,166

0.789

1.273

2.061

0.76

3 16-30 May 90

CONV FMCT

0,645 0,22

19.3 19.7

No No

2.S 2,3

1,56 6,39

1.64 1,56

2.9 1.6

7.4 6.2

4.2 27.1

1420 5009

3470 7804

0.795 0,2

6 0,702

2.467 3.651

10.467 4.353

0.82 0.75

4 9-24 Jul 90

CONV

0.205

20.6

Yes

1.51

3

1.53

No Detec

6.3

36,8

1097

2400

0,165

0

0.7

0.7

0,79

FMCT

0,162

20,5

Yes

3.44

9

2.5

1.3

6.2

31,4

3708

5500

0,153

0

1,676

1.876

0.75

5 20Aug-3Sep 90 CONV FMCT

0,4 0.2S2

22,7 22.6

Yes Yes

5.9 6.2

1.77 4.76

1.4 1.4

1.5 1.7

6.6 6.8

10.0 19,7

3136 5606

12485 16860

0.375 0.26

0 0

4.674 5.335

4.874 5.335

0.75 0.73

6 14-31

CONV

0,231

11.6

Yes

2.56

1.26

1.63

1.8

7.4

12.0

2346

6324

0.22

5.416

0.614

6.031

0.66

Jan 91 FMCT

0,207

8.6

Yes

3.14

1.57

2.65

2.9

7.3

.44.4

3067

8963

0.193

1.989

0.511

U

0.62

7 18Feb-8Mar91 CONV

0.579

6.4

Yes

1.76

1.11

1.93

1.8

7.5

4.6

650

2032

0.534

3.582

0.349

3.931

0.73

FMCT

0.429

6.1

Yes

6.58

3.29

2.51

3.3

7.2

13.6

3616

9356

0.392

13.43

1.607

15.237

0.65

UUzatlon rata (kg BOO removed/kg MLVSS.(Jay) Sludge wasted - OwJCa Effluent sludge (QI-Ow).VSSe Sludge wasted and lost - (Ow.Xa) (QH}w).VSSa

TABLE 5.2: HYDRAULIC DATA PERIOD DATE

a (domestic lndustriai)(m'/1i)

Q Industrial (m'/h)

Overflow Rate P.S. (m/h)

Retention Time P.S. (h)

Retention Time A.S. (h)

Overflow Rate S.S. (m/h)

Retention Time S.S. (h)

Solids Surface Load S.S. (kg/m'.h)

Blanket level (m)

TABLE 5.3: INFLUENT TO PILOT PLANT (Domestic & Industrial) PERIOD DATE

SS (mg/l)

VSS (mg/l)

B005T(mg/t)

B005 S (mg/1)

COO T (mg/l)

COD S (mg/l)

TXNT(mg/I)

TKN S (mg/l)

N-NH, (mg/l)

N-NO, (mg/l)

TOTAL P (mg/l)

P-PO. (mg/l)

ALKAUNITY (mmol/HCO,-)

OIL l OREASE (mg/l)

SULFIDE (mg/l)

CHLORIDE (mg/l)

PHENOLS (mg/l)

SURFACTANTS (mg/l)

CYANIDE T (mg/l)

1 16-29 Jan 90

262

217

386

148

1000

323

90.1

74.3

70.6

0.5

11.4

7.0

8.46

173

1.5

142.5

0,05

12.S

0.S2

2 26Feb-26Mar 90

343

260

375

146

622

96

72.4

0.3

10,4

9.1

6.46

66,6 '

1.9

143

0,043

14.4

0,178

3 16-30 May 90

237

190

377

166

717

330

61

70

63.4

0.4

14.2

13.2

7.72

56.3

2

91.9

14.4

4 9-24 Jul 90

232

150

194

35,5

409

109,4

34,5

23,5

24,4

0,2

6,1

5.4

4.62

28,5

1.2

407.6

0,013

7.2

0.139

S 20Aug-3Sep 90

260

177

234

44,9

508

127

34,3

23.5

23.9

0.2

5.6

5.3

5,98

51.6

1.8

445.3

0.011

8.9

0.052

6 14-31 Jan 91

250

169

207

63

422

156

43,9

34,9

30,2

0,4

5.5

2.5

4,76

32.3

1

233.6

0,052

6.8

0.15

7 18Feb-8Mar 91

319

213

236

70.3

562

156

483

37.7

32

0.3

5,8

3.8

4.32

54,5

1.3

487.9

0.186

11.1

0.19

Average values In every period.

CO

TABLE 5.4: METALS IN INFLUENT TO PILOT PLANT (Domestic & Industrial)

PERIOD DATE

CaT(mg/ l )

Mg T (mg/1)

Cd T (mg/l)

Cr T (mg/1)

Cu T (mg/l)

Fe T (mg/l)

Mn T (mg/l)

NI T (mg/l)

Pb T (mg/1)

Zn T (mg/l)

1 16-29 Jan 90

50.6

7.4

0.003

0,049

0.069

20

0.191

0,129

0.076

0.257

2 26Feb-26Mar 90

46.1

7,3

0,003

0.04

0.072

19.6

0.169

0.126

0,075

0,221

3 16-30 May 90

37,6

5,9

0,003

0,023

0,065

6.5

0.1

0.O97

0,072

0.274

4 9-24 Jul 90

72.6

23.1

0,002

0,045

0.097

24,9

0.239

0.131

0.09

0.25

5 20Aug-3Sep 90

92.2

36.4

0.005

0,031

0,074

23,5

0.247

0,07

0,102

0.277

6 14-31 Jan 91

97.2

24.1

0.004

0.013.

0.06

19

0.234

0.125

0.079

0.202

7 18Feb-8Mar 91

129

49,3

0.004

0,015

0,069

17.3

0.233

0.091

0.075

0.126

Average values in every period.

4 * CO

TABLE 5.5: PRIMARY CLARIFIERS EFFLUENT CSP1/USP1

PERIOD DATE

SS (mg/l)

VSS (mg/l)

B0O5 T (mg/l)

BOOS S (mg/l)

COD T (mg/l)

COD S (mg/l)

TKN T (mg/l)

TKNS(mg/l)

N-NH, (mg/l)

N-NO, (mg/1)

TOTAL P (mg/l)

P-PO, (mg/l)

ALKAUNrTY (mmol/HCO,)

OIL t, GREASE (mg/l)

SULFIDE (mg/l)

CHLORIDE (mg/l)

PHENOLS (mg/l)

SURFACTANTS (mg/l)

CYANIDE T (mg/l)

1 16-29 Jan 90

CONV FMCT

179

141

295

144

640

29a

79

67

66.4

0.3

11.4

11.9

7.76

56,9

1.7

133.9

11.8

0.37

2 26Feb-26Mar 90

CONV FMCT

194

151

316

145

674

65.2

66.1

0.2

10.1

10

6.12

51.9

2.1

132

14.3

0.22

3 16-30 May 90

CONV FMCT

4 9-24 Jul 90

CONV FMCT

63.6 109

63.7 62,8

114 133

41 43

256 285

116 111

30.1 30

23.6 23.6

24.5 23,4

0.2 0,2

6.9 6.7

5.6 S.5

4.52 4.32

295 363


133 132

96.6 99.6

159 143.5

57.8 45.5

326.6 322.4

137 139

33.2 33

26 24.5

25.2 24,8

0.21 0.16

5,8 5,7

S.9 S.5

6.16 5.22

423 381

6 14-31 Jan 91

CONV FMCT

138.2 139.3

99.3 100.1

159.1 153.1

63.6 63

331.3 341.1

137.5 140

39.9 39.8

33,7 33.5

29.7 26.4

0,3 0,4

5.1 4,9

2.7 2,6

4,6 4,56

217 207

7 18Feb-8Mar 91 CONV FMCT

158 177

113 123

161 174

83 73

406 418

171 166

46.6 43.3

37.6 36.3

32.8 30.6

0.1 0,3

6 5.6

4.9 4.1

4,42 4.24

438 519


TABLE 5.6: METALS IN PRIMARY CLARIFIERS EFFLUENT CSP1/UPS1

PERIOD DATE

Ca T (mg/))

Mg T (mg/l)

Cd T (mg/I)

Cr T (mgfl)

Cu T (mg/I)

Fe T (mg/1)

Mn T (mg/I)

NI T (mg/I)

Pb T (mg/I)

ZnT (mg/I)

1 16-29 Jan 90

CONV FMCT

41.7

6.6

0.003

0.019

0,036

6.6

0,125

0,093

0,043

0.154

2 26Feb-26Mar 90

CONV FMCT

41.8

6.6

0,002

0,026

0,046

6.9

0.105

0.096

0.05

0.172

3 16-30 May 90

CONV FMCT

4 9-24 Jul 90

CONV FMCT

0,009 0.013

0.026 0,032

5,6 9

0,072 0,095


0,016 0.018

0.031 0.03

9.1 10.5

0.044 0.047

6 14-31 Jan 91

CONV FMCT

0.006 0.005

0,037 0,037

7.19 7.32

0.091 0.092

7 18Feb-8Mar91 CONV FMCT

0.008 0,008

0,039 0.039

6,41 6.93

0.068 0,069

Average values In every perlod.

TABLE 5.7: FINAL EFFLUENTS CSP4/USP4

PERIOD DATE

SS (mg/1)

VSS (mg/l)

B005 T (mg/l)

BOOS S (mg/l)

COD T (mg/l)

COD S (mg/1)

TKN T (mg/l)

TKNS(mg/l)

N-NH3 (mg/1)

N-N03 (mg/l)

TOTAL P (mg/l)

P-P04(mg/I)

ALKALINITY (mmol/HCO,")

OIL t GREASE (mg/l)

SULFIDE (mg/l)

CHLORIDE (mg/l)

PHENOLS (mg/l)

SURFACTANTS (mg/l)

CYANIDE T (mg/l)

1 16-29 Jan 90

CONV

95

79.3

54.S

5.5

233

74

50.9

41.9

43

6.4

9

7.9

5.0

127.2

1.68

0.04S

FMCT

39.1

32.6

27.8

4.6

134

79.7

29,4

25,3

25,6

11.6

9

6.7

3.2

129.8

1.4

0,045

2 26Feb-26Mar 90

CONV

41.4

34.9

17.6

2.2

103

70.1

56.7

0.5

7.7

6.5

7.02

134.4

0.45

FMCT

30

26

17

3

112

70.2

61

1.8

7.5

7.8

7.06

133,9

0.49

3 16-30 May 90

CONV FMCT

53.6 82.9

45.7 66.4

25.2 38.2

3.9 1.7

132 143

62.8 46.4

53 15.5

47.5 9.8

46.4 5.2

0.6 23.7

10.9 12,2

9.7 11.4

5.74 1.28

91.6 86.4

4 9-24 Jul 90

CONV FMCT

32,6 27,9

26.7 22,7

12.7 9.5

2.6 2.5

74.9 64,5

27,9 28.1

7,6 7.2

5.3 5.1

0.5 0.5

22.8 22.7

5.3 5.8

4.4 4.5

0.56 0.64

276.1 297.8


47.2 36.6

34.3 27.1

16.9 10.8

2.5 1,3

93.3 74.1

40 30.4

11.9 7.9

7.1 5.9

6 Z.8

16.6 16.7

4.5 4.7

4,4 4.5

2.26 2.14

448.1 457.4

6 14-31 Jan 91

CONV

12,3

10,3

6

2.3

SI .6

34

31.2

28,8

25,7

0,6

2.8

2.3

4.16

192.9

FMCT

8.1

7

7.1

2.7

56

36

30.5

28.3

25.6

0.6

1.3

0.7

4.16

190


12,5 16.3

9.3 11.7

9 10.9

4.3 4.3

68 67.3

47.4 46.9

30.6 30.8

29.2 29

23.2 24.7

0.3 0.1

3.4 2.4

2.5 1.8

3.S4 3.70

432.2 472.4


Ol M

TABLE 5.8: METALS IN FINAL EFFLUENTS CSP4/USP4 PERIOD DATE

CaT(mg/l)

Mg T (mg/I)

Cd T (mg/I)

Cr T (mg/I)

Cu T (mg/I)

Fe T (mg/I)

Mn T (mg/I)

NI T (mg/I)

PbT(mg/I)

ZnT(mg/l)

1 16-20 Jan 90

CONV FMCT

49,1 47,2

6,97 e.55

0,003 0,002

0.016 0.006

0,043 0,026

9,4 1,6

0,104 0,092

0.1 0,063

0,039 0,026

0,149 0,113

2 26Feb-26Mar 90

CONV

41

6.18

0,002

0.011

0.015

1.69

0.062

0.073

0,019

0.033

FMCT

41,1

6,17

0.002

0.007

0,011

1,02

0,059

0,071

0,017

0,042

3 16-30

CONV

34,4

4,68

0.002

0,005

0,01

0,72

0,037

0,03

0,024

0,064

May 90 FMCT

36,9

9,13

0.002

0,014

0,024

3,56

0.069

0,055

0,031

0,019

4 9-24 Jul 90

CONV

0.019

0,016

1.5

0,064

FMCT

0,007

0,017

1.56

0,06


0.011 0.011

0,015 0,012

3.56 2,22

0,036 0,031

6 14-31 Jan 91

CONV

0,001

0.011

0.52

0.063

FMCT

0,001

0.019

0,37

0,061

7 18Feb-8Mar91 CONV

0,003

0,011

0.67

0,06

FMCT

0.003

0.01

0.7

0.059

Avenge values In every perlod.

O l CO

TABLE 5.9: DIURNAL VARIATIONS CONVENTIONAL SYSTEM

DATE: 12-Mar-91 (10:00h a.m.) to 13-Mar-91 (8:00h a.m.). Dry weather conditions.

HOUR

10

12

14

16

16

20

22

24

2

4

6

6

AVERAGE

MAX

MIN

Primary clarifier mg/l mg/l

COD-T COD-S

323 151

292 13S

319 151

403 159

356 151

348 159

364 162

360 143

311 131

253 111

222 115

216 67

314 139

403 162

216 67

effluent mg/l

TKN-T

37

36

45

45

45

43

39

31

29

23

22

20

34

45

20

mg/l N-NH3

29

32

3a

36

35

36

30

23

22

18

17

18

27

38

17

Final effluent mg/l mg/l

COD-T COD-S

59 46

61 46

49 46

49 44

49 44

49 44

56 44

49 44

49 37

49 26

49 28

52 32

51 40

61 46

49 28

Mixed liquor mg/l

COD-T

697

551

844

756

1019

873

697

580

551

990

756

287

716

1019

267

mg/l mg/l COD-S N-NH3

69 26

63 26

61 26

67 29

63 29

53 28

52 26

46 27

54 28

52 25

44 25

36 25

55 27

69 29

36 25

Recycle sludge mg/l

COD-T

2475

1743

1377

2036

2109

2109

2546

2914

2109

1616

1743

1616

2066

2914

1377

NOTE: CSP1 samples were taken from 13 Mar 91 to 14 Mar 91. with heavy rain between 2 am to 6 am (1< Mar 91) Operating conditions tn the Plant as Pertod 7.

CTI

TABLE 5.10: DIURNAL VARIATIONS FMCT SYSTEM

DAY: 12-Mar-91 (10:00h a.m.) to 13-Mar-91 (8:00h a.m.). Dry weather conditions.

Hour

10

12

14

16

IB

20

22

24

2

4

6

e

AVERAGE

MAX

MIN

Primary mg/l

COD-T

190

364

475

568

745

606

407

230

162

135

79

63

336

745

79

clarifier effluent mg/l mg/l

COD-S TKN-T

112 27

177 71

273 62

251 42

333 39

257 34

205 26

130 20

96 15

63 13

36 6

44 10

164 30

33 71

36 6

mg/l N-NH3

20

56

47

26

26

22

19

15

11

. 9

S

7

22

56

5

Final effluent mg/l mg/l

COD-T COD-S

SB 41

56 46

49 32

79 44

70 46

73 57

73 55

79 53

79 52

79 53

73 53

73 53

70 46

79 57

49 32

Mixed liquor mg/l mg/l

COD-T COD-S

3445 127

4968 173

4733 160

3445 113

5612 169

4499 95

4323 B1

3503 50

3503 40

3737 35

3503 44

4323 40

4132 95

5612 160

3445 35

mg/l N-NH3

31

36

51

38

29

43

30

24

23

23

25

25

31

51

23

Recycle sludge mg/l

COD-T

19008

19740

17397

21790

21937

21790

22B15

20765

19008

21056

20912

19008

20436

22815

17397

NOTE: USP1 samples were taken from 13 Mar 91 to 14 Mar 91, with heavy rain between 2 am to 8 am (14 Mar 91) Operating conditions in the Plant as Period 7.

Ul

TABLE 5.11: ACTIVATED SLUDGE MASS BALANCE (1)

PERIOD DATE

Blanket level 0 (m)

Blanket level 1 (m)

Recycle VSS 0 (kg/m')

Recycle VSS 1 (kg/m*)

MLVSS 0 (kg/m1)

MLVSS 1 (kg/m")

Sludge volume In settler 0 (m1)

Sludge volume In settler 1 (m3)

VSS In settled sludge 0 (kg/m1) (1)

VSS In settled sludge 1 (kg/m*) (1)

Sludge mass In settler 0 (kg)

Sludge mass In settler 1 (kg)

Sludge mass In alratlon tank 0 (kg)

Sludge mass In alratlon tank 1 (kg)

1 16-29 Jan 90

CONV FMCT

2,9 0,49

2.3 1,75

5.22 9,06

6.61 11,38

2,59 2,796

3.77 4,819

6.71 0,14

4,43 G.49

3,47 4.55

4.72 7.01

23.26 0.64

20.69 45.47

46.62 50.22

67.66 66,76

2 26Feb-26Mar 90

CONV

2.93

2.97

5,71

2.72

2.20

1.63

6.63

6.98

3.37

1,99

23,02

13.91

39.60

29.34

FMCT

2,67

3,7

11.10

11.02

4.27

5.11

20.5

30.92

6,55

7.06

134.21

216.91

76.66

91,98

3 16-30

CONV

3.27

2.3

3.72

3.92

1.52

1.55

6.23

4.43

2.2S

2.34

18.54

10.37

27.36

27.90

May 90 FMCT

1.63

1.45

6.70

8.06

4.68

4.80

5.24

3.69

5.35

5.69

28.05

21.72

64.24

86.40

4 9-24 Jul 90

CONV

No detec

No detec

2,49

2.42

1.20

1.07

0

0

1.63

1.52

0

0

21.60

19.26

FMCT

1.17

1.33

4.67

4.93

3.66

4.30

1.94

2.85

4.20

4.51

8,14

12,85

69.5

77.40

5 20Aug-3Sep 90 CONV

1.63

2,55

5.62

12.628

2.67

3.20

1.9

5.36

3.65

6.34

6.94

34.13

48.06

57.60

FMCT

1.77

1.97

9.37

20.924

5.40

S.13

6.72

9.18

6.72

10.39

45.16

95.41

97.20

92.34

6 14-31 Jan 91

CONV

1.97

1.43

7.116

5.428

2.94

1.65

3.16

1.26

4,33

2,91

13,76

3,72

52.92

29.70

FMCT

3,10

2,9

6.664

11.924

2.84

3.33

23.36

20.87

4.76

6.19

111.76

129.25

51.12

59.94

7 18Feb-8Mar91 CONV

1.6

1.9

2.918

1.264

0.63

0,74

233

2.91

1.93

0.91

3.8S

2.66

14.94

13,32

FMCT

3.4

3.27

6,2

9.412

3.72

3.86

27,15

25.52

5.21

5.71

141,54

145.72

66.96

69.46

(1) VSS In settler sludge - (2 . MLVSS + Recycle VSS)/3

0 - Beginning of period

1 - End ot period

Ol

TABLE 5.12: ACTIVATED SLUDGE MASS BALANCE (2)

PERIOD DATE

DAYS

Sludge wasted and lost (1) (kgVSS/day)

Removed BODS (kg/day)

Sludge mass 1 A.S. (kg)

S.S. (kg)

Total(kg)

Sludge mass 0 A.S. (kg)

S.S. (kg)

Total(kg)

Sludge mass balance (kg) (2)

Total removed BODS (kg)

Observed Yield (kgVSS/kg BOD5) (3)

1 16-29 Jan 90

CONV FMCT

14 14

6.79 2.16

14.5 16.3

67.9 86.8

20.9 45.5

36.6 132.2

46.6 50.2

23.3 0.6

69.9 50.9

113.9 111.6

203.1 226.2

0.56 0.49

2 26Feb-26Mar 90

CONV

29

a.60

15.0

29.3

13.9

43.3

39.6

23.0

62.6

230.1

435.1

0.53

FMCT

29

2.06

15.2

92,0

216.9

310.9

76.9

134,2

211.1

159.6

439.4

0.36

3 16-30

CONV

15

10.49

19.9

27.9

10.4

36.3

27.4

18.5

45.9

149.7

299.1

0.50

May 90 FMCT

15

4.35

16.0

66.4

21.7

108.1

64.2

28.1

112.3

61.1

269.7

0.23

4 9-24 Jul 90

CONV

16

0.70

3.6

19.3

0.0

19.3

21.6

0.0

21.6

8.9

57.4

0,15

FMCT

16

1.86

10.1

77.4

12.9

90.3

69.5

8.1

77.6

42.6

161,1

0.26


15

4.87

20.2

57,6

34.1

91.7

46,1

6.9

55,0

109.6

303.6

0.36

FMCT

15

5.34

26.3

92,3

95,4

187,6

97,2

45,2

142.4

125.4

395.2

0.32

6 14-31 Jan 91

CONV

18

6.03

9.1

29.7

3.7

33,4

52,9

13,8

66.7

75.3

164.6

0.46

FMCT

16

2.50

10.7

59,9

129,3

189,2

51.1

111.8

162,9

71.3

192,0

0,37

7 18Feb-BMar91 CONV

19

3,93

6,2

13,3

2.7

16.0

14.9

3.9

18.8

71.9

117.8

0,61

FMCT

19

15.24

25.4

69,5

145.7

215.2

67.0

141.5

208.5

296.2

462,0

0,61

(1) Sludge wasted and lost - (Ow.Xa) + (O-Ow).VSSe

(2) Sludge mass balance - (Sludge mass 1) (Sludge mass 0) + (Sludge wasted and lost N 8 days)

(3) Observed Yield - sludge mass balance / total removed B0D5

A.S.: Activated sludge S.S.: Secondary settler

0 : Beginning of period 1 : End of period

or

TABLE 5.13: SLUDGE QUALITY PERIOD DATE

SVI (ml/g)

Senang Velocity (m/h)

Blanket level (m)

Filamentous Microorganisms (Relative abundance)

Nocardia

S. natans

T.1701

H. hydrossls

T.1663

T.0041

Fungi

Zooglea

MLSS (mg/l)

MLVSS (mg/l)

1 16-29 Jan 90

CONV FMCT

104 119

1.32 0.9

2.1 1.4

1

-----

2

-3177 4476

2642 3630

2 26Feb-26Mar 90

CONV FMCT

273 140

0,35 0.06

2.5 3.1

4 3

2

+ -

-----

2749 6714

2194 5091

3 16-30 May 90

CONV FMCT

299 99

0.66 0.36

2.9 1.6

4 4

-3

1

+ -

---

1735 6671

1420 5009

4 9-24 Jul 90

CONV FMCT

51 65

4,3 1.7

No detec 1,3

3 2

-- 1

-+

--

1395 4927

1097 3708


44 41

3.4 1.8

1.5 1.7

2 3

1

-+ -

-+ +

--

4186 7718

3138 5606

6 14-31 Jan 91

CONV FMCT

143 167

0.7 0.2

1.8 2.9

3

1

---- +

-++ +

3585 5073

2346 3087


426 107

0.7 0.6

1.6 3.3

4 1

2

4

+ -

-1

--

887 5527

650 3618

N O T E 1

Relative Abundance of Microorganisms (by Eikelboom)

* Sporadic growth of filamentous microorganisms

1 Low growth of filamentous microorganisms

2 Moderate growth of filamentous microorganisms

3 High growth of filamentous microorganisms

4 Excesive growth of filamentous microorganisms

5 Field ol view f u l l of filamentous microorganisms

NOTE 2

Zooglea++ : very abundant

NOTE3 Settling velocity depends on MLSS concentration

CJ1 00

TABLE 5.14: METALS IN PRIMARY SLUDGE CSP7/UPS7

PERIOD DATE

Ca (mg/kg dry sludge)

Mg

Cd

Cr

Cu

Ft

Mn

NI

Pb

Zn

Hg

SS (mg/t)

VSS(mg/l)

1 31 January 90 CONV FMCT

29033

1750

3,2

127

565

77156

372

587

99

496

ND

13180

9700

2 14 March 90

CONV FMCT

32597

2535

3.6

326

257

141163

525

154

168

733

NO

14660

9019

3 30 May 90

CONV FMCT

4 25 July 90

CONV FMCT

5 4 September 90

CONV FMCT

41609 41339

3674 3246

4 5.9

55,6 57,1

179 175

73168 71260

371 378

127 120

218 217

663 644

1.32 0.79

35906 36876

22836 22S76

6 1 - 4 Feb 91

CONV FMCT

40444 26666

5227 4675

1.9 2

27.6 113

152 244

34819 130746

203 282

90.7 143

159 91,5

471 539

0.67 0.42

30552 16000

20783 9937

7 8 March 91

CONV FMCT

26480 25489

4516 1983

5.6 5.3

133 136

460 492

179325 192094

1162 1245

997 1057

160 154

962 1018

0.12 0.25

31044 12052

15752 5980

CJI co

TABLE 5.15: METALS IN ACTIVATED SLUDGE CSP2/USP2

PERIOD DATE

Ca (mg/Kg dry sludge)

Mg

Cd

Cr

Cu

F

Mn

NI

Pb

Zn

Hg

SS (mg/t)

VSS(mg/l)

1 31 January 90 CONV FMCT

14052 11367

2213 221B

2.2 5.5

77.5 83.2

232 302

32197 36180

177 175

166 163

117 125

549 571

ND NO

4925 6333

4143 5348

2 14 March 90

CONV FMCT

17915 22972

2932 2948

2.2 4.1

126 679

219 360

35940 50823

224 335

165 218

124 157

569 874

NO NO

3198 7858

2572 5882

3 30 May 90

CONV FMCT

28098 20067

3549 3559

3 5.9

82.6 142

157 204

18338 36576

139 214

148 190

160 182

704 1018

ND NO

1934 6460

1584 4S66

4 25 July 90

CONV FMCT

15113 13781

4220 4064

3.9 5.3

70.7 74.2

347 346

69971 73852

296 244

214 249

236 228

983 682

2.1 3,1

1846 3218

1338 2512

5 4 September 90

CONV FMCT

23894 23019

2962 3302

3.9 3.9

43.4 46.6

182 183

62796 68376

434 377

168 177

146 153

551 596

0.49 1,31

5344 8380

3744 5648

6 1 - 4 Feb 91

CONV FMCT

27733 28759

4489 6291

5.9 4

35.9 43,9

223 219

55466 62706

295 393

189 173

143 173

63S 663

1.11 1.06

2377 5334

1657 3472

7 8 March 91

CONV FMCT

18337 22303

3906 5100

6,4 8.3

25.8 38,3

75.5 170

332S2 35507

195 268

66 91

126 146

460 548

0.68 0,79

958 5456

766 3816

O! O

TABLE 5.16: AERATION PARAMETERS

PERIOD DATE

Temperature (deg C)

Specific OUR (motygVSS.h)

OUR (mgOa/Lh)

D.O. (mgOj/l)

Air Flow (m'/h)

Relation Air Flow C/F

Energy In Aeration (kw.h)

Relation of Energy In Aeration CVF

1 16-29 Jan 90

CONV FMCT

12.9 13,2

19,62 19,56

56,72 70.48

0.97 2.65

69 93,2

0.74

1393 1126

1.23

2 26Feb-26Mar 90

CONV FMCT

15,6 16,4

12,35 9,92

26,9 43,66

1.6 2,07

46 55

0,64

765 045

0,91

3 16-30

CONV

19,3

19,35

29.11

1,64

67

0.67

465

0.58

May 90 FMCT

19.7

15,61

79.7

1.56

100.6

796

4 9-24 Jul 90

CONV FMCT

23.7 23,7

13.64 12.35

16 53.3

1,53 2.5

32 63.5

0.50

256 500

0.51


22.7 22.6

22,77 19,50

69 109,7

1.4 1.4

96.5 118.8

0.81

768 922

0,63

6 14-31 Jan 91

CONV FMCT

6.4 8.3

6,38 11.04

17,42 39,66

1,63 2,65

33 37,4

0.88

301 349

0.66

7 18Feb-8Mar 91 CONV FMCT

8.4 8.2

22,1 19.11

19.34 83.84

1.93 2.51

30 63

0,48

301 660

0.46

C/F- CONV Une Value FMCI Une Value

OUR - Oxygen Uptake Rate

TABLE 5.17: ENERGY CONSUMPTION

PERIOD DATE

Energy In Recirculation pumps (kw.h)

Energy In Blowers (kw.h)

Total Energy (Kw.h)

CD (mVh)

Ndays

Flow Treated (m1)

Energy Consumption Total (kw.h/m*)

Energy Consumption In areatlon (kw.h/m*)

B005 Removed (kg)

B005 Removed (kg/day)

Energy Consumption Total (kw.h/kgBCO)

Energy Consumption (kw.h alratlon/kg BOO)

Air Consumption (m'/day)

m* alr/kg BOO removed

1 16-29 Jan 90

CONV

76

1393

1469

2.53

14

650.06

1.73

1.64

203.1

14,51

7.23

6.66

1.656

114.13

FMCT

62

1126

1190

2.54

14

S53.4

1,40

1.32

226,2

16.3

5,22

4,94

2.237

137.24

2 26Feb-26Mar 90

CONV

146

765

913

2.07

29

1440,72

0.63

0.53

435.1

15,0

2,10

1.76

1.104

73.6

FMCT

129

S4S

974

2

29

1392

0.70

0.60

439.4

15.15

2.22

1.92

1.320

67.13

3 16-30

CONV

75

465

540

2.5

15

900

0.60

0.51

299.1

19.93

1.61

1.5S

1.608

60.66

May 90 FMCT

3S3

799

1151

2.3

15

626

1.39

0.96

269,7

17,96

4.27

2.96

2.414

134.26

4 9-24 Jul 90

CONV

114

256

370

1.51

16

579.8

0.64

0.44

57.4

3.58

6.45

4.45

766

214.5

FMCT

300

500

600

3.44

16

1320.9

0.61

0.36

161.1

10.06

4.97

3.10

1.524

151.49


66

768

854

5.9

15

2124

0,40

0,36

303,6

20,23

2.B1

2.S3

2.316

114.46

FMCT

1S3

922

1075

6.2

15

2952

0,36

0,31

395,2

26,34

2.72

2.33

2.651

108.24

6 14-31 Jan 91

CONV

77

301

378

2.56

18

1105.92

0.34

0.27

164.6

9.14

2.30

1.63

792

86.65

FMCT

70

349

419

3.14

18

1356.48

0.31

0.25

192.0

10.66

2.16

1.61

896

84.24

7 18Feb-8Mar91 CONV

68

301

369

1.76

19

811.66

0.4S

0,37

117.6

6.20

3.13

2JJ

720

116,13

FMCT

142

660

602

6.58

19

3000.48

0.27

0.22

462.0

2S.36

1.66

1.37

1.512

59.62

Note: In period 1 atr diffusera were clogged and were replaced for new ones In period 2. So that the Energy consumption In blowers In period 1 is much higher than In other periods.

TABLE 5.18 : SLUDGE AGE CALCULATION

PERIOD DATE

Temperatur (*C]

Ntdays

Fexcese (kg VSS/day)

Mxl (kg)

MxO(kg)

(MX1-MMO)/N (kg/day)

(MK1MXO)/2 (kg)

[(Mx1-MxO)/N]Fexce>s (kg/day)

Total aludge age (days) (1)

Va.Xa (kg)

Aerobic sludge age (day) (2)

N-NH3 In effluent (mg/l)

1 16-29 Jan 90

CONV

12.9

14

6.79

60.8

69.9

1.3

79.4

6.1

9.6

47.6

5.6

43.0

FMCT

13.2

14

2.16

132,2

50.9

9.6

91,6

6.0

11.5

65.3

6.2

25.6

2 26Feb-26Mar 90

CONV

15,6

29

6.60

43.3

62.6

-0.7

53.0

7.9

6.7

39.4

5.0

58.7

FMCT

16.4

29

2.06

310.9

211.1

3.4

261.0

5.5

47.4

91.6

16.7

61 J)

3 16-30

CONV

19.3

15

10.49

36.3

45.9

-0,5

42,1

10,0

4.2

25.6

2.6

46.4

May 90 FMCT

19.7

15

4.35

106.1

112.3

-0.3

110.2

4.1

27.1

90,2

22,1

5.2

4 9-24 Jul 90

CONV

23,7

16

0.70

19,3

21.6

-0.1

20.5

0.6

36.6

19.6

35.5

0.5

FMCT

23.7

16

1,66

90,3

77,6

0,6

64,0

2,7

31.4

66.7

25.0

O.S

5 20Aug-30Sep 90

CONV FMCT

22.7 22.6

15 15

4.67 5,34

91.7 167.6

55,0 142,4

2,4 3,0

73.4 165,1

7,3 6,4

10.0 19.7

56.5 100,9

7.7 12,1

6.0 2,6

6 14-31 Jan 91

CONV

6,4

16

6,03

33,4

66.7

-1.9

50.1

4.2

12.0

42.2

10,1

25.7

FMCT

6.3

1B

2.50

169,2

162.9

1.5

176,1

4,0

44.4

5S.6

14.0

25.6

7 18Feb-8Mar 91 CONV

6,4

19

3.93

16.0

16.6

-0.1

17,4

3,6

4,6

11.7

3.1

23.2

FMCT

6.2

19

15,24

215.2

206.5

0.4

211.9

15,6

13.6

65.1

4.2

24.7

(1) Total sludge age (days) -

(2) Aerobic sludge age (days) -

(Mx1+Mx01/2 [(Mx1-Mx)/NJ+(-excess

Vo.Xfl L(Mx1-Mx)7NJ+t-excess

Fexcess -

Mx1 -

MxO-

Sludge wasted and lost (kgVSS/d)

Total sludge mass (kg) end of period

Total sludge mass (kg) beginning of period

((Mx .Mx0)/N]+Fexcess - Sludge acumutated En the system (kg/day) + sludge wasted and lost (kg/day)

VauXa - Average sludge mass In alratlon tank (kg)

O)

-64-

6 MODELLING

6.1 Introduction To verify and analyze the obtained experimental data against the known theory, a

computer program CAB (Consorcio de Aguas, Bilbao) was developed. The program includes current theory for activated sludge reactors and clarifiers, and is therefore a valuable tool which can be used in understanding and interpreting measured data.

This chapter shortly describes the implemented mathematical models, the model set up of the plant and the results obtained from calculations with the program.

6.2 Concepts and models The process model used in CAB is based on the IAWPRC Activated Sludge Model

No 1. (Henze et al, 1987), and for the secondary clarifiers on the flux theory adapted for modelling with the activated sludge models (Dupont, 1991).

6.2.1 Activated sludge model The model for activated sludge is presented in figure 6.1. Explanations of the

components and constants are found in the symbol list at the end of the chapter. The model is a slightly expanded version of the original Activated Sludge Model No. 1 (Henze et al, 1987).

To prevent numerical problems for components in the model which have a negative stoichiometric constant, a few new terms are added to some of the processes. Finally, three new components (Particulate precipitated compounds Xpg, Particulate orthophosphate XPO, soluble phosphate SP0) and three new processes (process 10,11 and 17) are added to deal with simultaneous precipitation.

A general description of the included components and processes can be found in numerous papers (Henze et al, 1989; Gujer, 1991).

Component -

Process I

1 Aerobic growth

of heterotrophic

*BH XBA Xpo

12 13

Spo

14

Y-1

17 Process rates

M L " J - T n

I V NH AIK ^H^SR K Q H ^ O ^NH^NH ÂHÂIK

2 Anoxic growth

of heterotrophic -1*YH 1-Yu f, 2,86-YH

MH-*OH SN

K S H ^ S R KOH'SO KNOH' , SNO K N H ^ N H KAH'SAU 3 decay of

heterotrophic 1-f.

4 Aerobic growth

of autotrophic

5 Decay of

autotrophic

6 Hydrolysis of

Particulate

7 Hydrolysis of slowly

degradable

8 Hydrolysis of

particulate organic

9 Ammonification.

10 Iron oxidation.

11 Precipitation.

12 Resolubilisation.

1-f.

U-l. -

^ " Y T ->nb 1 YA-4.5

14

" H - * B H

KA-So

K N A ^ N H KOA*SQ KAAÂLK XBA

B A - X B A

KHX- Xs- ( 1 2 H ) - X B H

^HS'S'XBH

nu ,e.

^HND-^ 'fO)

-2 3 J 6 T Ket' S0- KAOÂLK - S n 2_

31 *ME PÔ *FE

-2 31 Kpo'

Figure 6.1 Activated sludge model matrix. 05 o

-66 -

6.2.2 Secondary clarifier model The model for the secondary clarifier is based on the zone settling theory for sedimen-

tation in clarifiers described among others by Vesilind, 1979, and Ekama et al, 1984, and adopted for use with activated sludge models by Dupont, 1991.

The conceptual idea by the implemented secondary clarifier is shown in figure 6.2. The clarifier is regarded as a flat bottom cylindrical tank with a given height and a given area, in which an inlet is placed in a given depth, from which there is an upward flow and a downward flow. These flows together with the gravity settling of the particles gives the flux expressions for the upper an lower part of the clarifier. Total flux expression :

GT = Gt + GF = VXs * VpXs (6.1)

: Total flux Gravity flux : Flow flux

Figure 62 Conceptual model for clarifier.

Vg : Settling Velocity Xss: Sludge concentration. VF : Flow velocity

Expression for flow velocity:

V =

^F =

A R+ p

for h > h .,

for h < h inlet

(6.2)

A : Area of clarifier h : Height of clarifier QE : Effluent flow QR : Return sludge flow Qp : Waste sludge flow

67

Expression for settling velocity:

Vt = V0- e -h-Xs (63)

V0 : Max settling velocity due to gravity k : Sludge quality constant

Inserting expression 6.2 and 6.3 in the total flux expression 6.1 the following expressions for flux in the upper and lower part of the clarifier are obtained:

Gj. =

GT =

{ ~ J Xs for h > h jnJet

2 p ' J for h < h

(6.4)

(6.5)

To be able to model the sludge which does not settle in the clarifier, the following empirical model is used for suspended solids in the inlet to the clarifier.

-^NS = -^ ln i t + -*^N03 'NO,

^N03+^N03 (6.6)

YNS xs, xs, Init N03 ^N03

: Non settled suspended solids in inlet to clarifier which will not settle : Floating particles in the inlet to the clarifier. : Max concentration of suspended solids due to nitrate in the inlet to the clarifier, which will not settle. : Monod constant for nitrate. : Concentration of nitrate in the inlet to the clarifier.

Applying model 6.4, 6.5 and 6.6 to mass balances over tiny elements of layers in the clarifier, the concentration profile in the clarifier can continuously be calculated over time by integration.

- 6 8 -

6.3 CAB description CAB (Consorcio de Aguas, Bilbao) is a dynamic simulation program developed for this

project. The purpose of the program has been to develop a program which could be used as an analyzing tool and which could support the work of verifying and analyzing the experimental data. In the development of the program special attention is paid to the clarifier part, because the differences in clarifier design is a key factor in the difference of the two pilot plant lines.

One of the goals for the program was that it should be possible to run the program on any PC type computer. This has been achieved, but reasonable minimum hardware requirements would be PC with a 286 processor, a mathematical co-processor and a graphic screen.

-CAB Version 1.0-Plant Operatio Constants Presentation System utilities Exit Plant Table of plants Flow scheme Ctrl-T Dimensions

Dimensions Volume of Activ, sludge 1 Surface aeration (Kla) for Activ, sludge 1 Surface area of Final sed. 1 Height of Final sed. 1 Position of inlet in Final sed. 1

18 1

12 4 1

0 0

5 4 3

ra 3 1 / d

m3 m m

Plant: USP Influent: Const: RAH Max : 213016 Avail: 213008 bytes Input tank volumes Help Save

Figure 63 Example on user interface from CAB.

The program is driven by pull down menus (Figure 6.3), from where the different tasks can be operated. This includes : - Possibilities for setting up the configuration and dimensions of the plant. - Possibilities for operating the designed plant with different controls and operating

strategies. - Possibility to simulate dynamic load conditions. - Possibility for calibrating the model by adjusting

european water treatment code

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