ACO ClarA 19-38 User manual

Waste water treatment plant
ACO ClarA
19-38, 24-48, 30-60, 38-76, 48-96, 60-100
Operation manual

2
Operation manual
ACO Clara
1 Introduction............................................................................3
1.1 What water we can treat .......................................................3
2 Safety......................................................................................4
2.1 General requirements regarding occupational safety .............4
2.2 Protection against accidents ..................................................4
2.3 Protection against infections caused by waste water.............4
3 Description of plant................................................................5
3.1 General description.................................................................5
3.2 Check of plant type, nameplate..............................................7
3.3 Cover ......................................................................................7
3.4 Inlet and outlet pipes..............................................................8
3.5 Air-lift pumps..........................................................................8
3.6 Blower.....................................................................................8
3.7 Mechanical pretreatment .......................................................9
3.8 Activation tank .......................................................................9
3.9 Final sedimentation tank........................................................9
3.10 Ventilation pipe ......................................................................9
4 How the plant works ............................................................10
5 Installation ...........................................................................10
5.1 Transport and storage..........................................................10
5.2 Installation of blower ...........................................................10
5.3 Plant ventilation...................................................................10
5.4 Construction requirements....................................................10
5.5 Electrical installation ............................................................11
5.5.1 1 phase motor ......................................................................11
5.5.2 3 phase motor ......................................................................11
6 Operation and maintenance instructions.............................13
6.1 Plant commissioning ............................................................13
6.2 Records of plant operation...................................................13
6.3 Accessories for plant operation.............................................13
6.4 Description of individual checks and maintenance work......14
6.4.1 Check of blower function......................................................14
6.4.2 Aeration in activation tank ..................................................14
6.4.3 Functions of air-lift pumps....................................................15
6.4.4 Tank level of mechanical pretreatment, inlet pipe ................15
6.4.5 Level of final sedimentation tank and outlet object .............15
6.4.6
Quality of treated water ........................................................15
6.4.7 Check of concentration of activated sludge – sedimentation test .....15
6.4.8 Check of treated water .........................................................15
6.4.9 Discharging of condensate water from aeration system ......16
6.4.10 Discharging of surplus sludge...............................................16
6.4.11 Discharging of mechanical pretreatment tank .....................16
6.4.12 Cleaning of tank walls..........................................................16
6.4.13 Cleaning of air-lift pumps.....................................................16
6.4.14 Replacement of aeration elements........................................17
6.5 Sampling ..............................................................................17
6.5.1 Sample at inlet .....................................................................17
6.5.2 Sample at outlet ...................................................................17
6.5.3 Sample of activated sludge...................................................17
6.6 Plant breakdown ..................................................................18
6.6.1 Short-term operational constraints ......................................18
6.6.2 Long-term shutdown ............................................................18
7 Troubleshooting....................................................................19
8 Certification..........................................................................20
9 Operation manual for blowers .............................................21
9.1 Installation ...........................................................................21
9.2 Ambience ..............................................................................21
9.3 Medium quality ....................................................................21
9.4 Piping ...................................................................................21
9.5 Storage .................................................................................21
9.6 Maintenance and service......................................................21
9.6.1 Filter element cleaning..........................................................22
9.6.2 Filter element replacement....................................................22
9.6.3 Valve box, diaphragm replacement......................................22
9.6.4 Reset of auto stopper............................................................23
9.6.5 Magnet replacement.............................................................24
9.7 Pictograms for maintenance and service..............................25
9.8 Maintenance and service for lamella blowers DT 4.25 and DT 4.40.... 26
9.9 Maintenance and service for side channel blower SV 5.250/2 ......30
9.10 Maintenance and service for side channel blower SV 8.190 ..........34
List of contents:

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Operation manual
ACO Clara
This manual is valid for type line: ACO Clara 19-38
ACO Clara 24-48
ACO Clara 30-60
ACO Clara 38-76
ACO Clara 48-96
ACO Clara 60-120
When you are fully familiarized with this document, you will be able to
understand all the functions of ACO Clara waste water treatment plants
(hereinafter referred to as plants) and to ensure their safety and reliable
operation.
If all the instructions given in this manual are followed it will ensure com-
pliance with all safety instructions for the operation of plants, correspon-
ding with currently valid standards, rules, and safety procedures.
Following other operating procedures than those laid down in this manual
without the manufacturer’s approval would be considered as unsuitable or
otherwise unsatisfactory and would result in a loss of the ability to claim
for repair under guarantee within the guarantee period.
The illustrations used in this manual are only of an informative character
and they are not necessarily in accord with your type of plant.
You will meet some important warnings highlighted in this manual:
Warning, which if not respected, may cause
a risk for persons or property, eventually resul-
ting in serious damage to the treatment effect.
Important warning for proper plant operation.
Other important warnings.
1 Introduction
!
The ACO Clara plants were designed for the treatment of municipal
waste water. This water, which is dumped from houses or services, is
produced mainly as a product of the human metabolism and household
activities (domestic sewage). It can originate in households by the conne-
ction of a WC, bathrooms and kitchens. Contact the manufacturer in the
event of any origin of domestic sewage other than the above-mentioned
ones.
Grease must be removed from the water from
industrial kitchens using an appropriate grease
separator.
The usage of garbage disposal units significantly
increases the mass load of waste water and has
to be taken into account when choosing the
correct size for the plant.
The treatment effect is developed as a result of the activities of microor-
ganisms, which could be seriously damaged by the composition of the
waste water on the inlet side.
The waste water must not contain:
Oil products, paints, and solutions
Acids and alkalis
Heavy metals
Drugs and toxins
In relation to the biological system providing the treatment effect, allo-
wance should be made in regard to the following activities:
Disinfection – disinfectants should be used to such an extent that they
do not harm the bacteria in the plant. Sanitary hygiene disinfectants are
intended for the elimination of microorganisms and so they can be used
only to a limited extent.
Fats and oils – a large quantity of used fats and oils significantly impa-
irs the living conditions for bacteria.
Washing clothes – it is recommended to use detergents that are biolo-
gically well degradable and to avoid the frequent washing of clothes wit-
hin a short period.
!
!
1.1 What water we can treat
!
Rainwater or other ballast waters must not be
allowed to flow into the plant.

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Operation manual
ACO Clara
2.2 Protection against accidents
By electric shock
Only persons with suitable electro technical qualifications can access the
electrical installation.
Work on electrical equipment or handling it
must not be done with wet hands, even in
rubber gloves.
Disconnect the line cord immediately if dama-
ged and ensure its repair by a qualified person.
Before doing any work on the electrical
equipment it is imperative to check that
the electric power is switched off.
By falling inside
The plant is an underground object which has an opening just above
ground level, so there is a risk of falling inside.
The interior of the plant can be wet, with a risk of slipping.
Leave the cover open only for the period
necessary for the checking, maintenance or
servicing of the plant.
Never leave the plant with the cover open.
!
!
!
2.3 Protection against infections caused by waste water
Waste water can become the source of serious infections,
so it is undesirable to come into direct contact with the
water in the plant.
Disinfect the affected area in the event of direct contact of water from
the plant with the skin.
In the event of the ingestion of water or an accident involving direct con-
tact between the injured area and the water, seek medical assistance.
When working with the plant follow the basic sanitary principles; do not
smoke and drink. Wash your hands with soap after work.
Tools that have been in direct contact with the plant water must be tho-
roughly washed and stored in a suitable place.
2 Safety
2.1 General requirements regarding occupational safety
All work related to the operation and maintenance of the plant should
only be performed by persons manually and mentally qualified for such
activity, namely after thorough familiarization with this manual. In the
course of this work the stress must be placed on the safety of the per-
sons carrying out the work and other persons in the vicinity of the plant.
Do not allow children to come into contact with the plant.
When operating the plant always use protective devices
in accordance with the occupational safety provisions.
It is recommended that two persons operate and maintain the plant.
Enter the plant only in the case of necessity.
If access to the vessel is needed, the person
inside must be safeguarded by a second person
outside who is in permanent visual contact.
!
An electric shock can cause serious health
problems or death.

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Operation manual
ACO Clara
3 Description of plant
The waste water treatment plants of the ACO Clara line (hereinafter refer-
red to as plants) consist of a main tank made of polypropylene divided
into other technological parts. The sewage water is brought by the inlet
pipe (Pos. 1) to the pre-treatment tank. From here the pretreated waste
water is pumped to the biological part of the plant, consisting of an aera-
ted activation tank (Pos. 5) and a final sedimentation tank (Pos. 6), from
where the treated water is drained by an overflow across the drain of the
plant into a outlet pipe (Pos. 2) connected to a storm drain or drained
away directly to a receiving body. Accesses to the tank are provided by
a fiberglass covers (Pos. 7).
1. inlet pipe
2. outlet pipe
3. ventilation pipe
4. pre-treatment
5. activation tank
6. finally sedimentation tank
7. access cover
8. aeration element
9. raw sewage water air-lift pump
10. return sludge air-lift pump
11. surplus sludge air-lift pump
12. connecting of air supply hose
13. air distributor
14. outlet object
15. manipulation board
3.1 General description
Description:
1
3
12 13 9 5 2
15 610 11 8
4
13
12
3
1
4
8
5
6
14
2
15 7

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Operation manual
ACO Clara
Technical information
ACO Clara 19 - 38 24 - 48 30 - 60 38 - 76 48 - 96 60 - 120
Lenght L [mm] 3740 4140 4636 5240 5890 7290
Width W [mm] 1740 1890 2036 2190 2390 2390
Height H [mm] 2940 2940 2940 2940 2940 2940
Height of inlet pipe H1 [mm] 880 880 880 880 880 880
Height of outlet pipe H2 [mm] 980 980 980 980 980 980
Depth of water level H3 [mm] 1950 1950 1950 1950 1950 1950
Height of ventilation pipe H4 [mm] 610 610 610 610 610 610
Weight [kg] 1165 1365 1580 1840 2150 2580
Power supply [V/Hz] 230/50 230/50 400/50 400/50 400/50 400/50
Power input [kW] 0.43 0.43 0.75 0.75 0.98 1.30
Article no. 411006 411007 411008 411009 411010 411011
H1
L x W
H2
H4
Air supply pipe
H
H3
Outlet
DN 200
Inlet
DN200
Ventilation
DN100
ACO Clara 19 - 38 24 - 48 30 - 60 38 - 76 48 - 96 60 - 120
Nominal size in PE 32 40 50 63 80 100
Nominal hydraulic load [m3/day] 4.8 6.0 7.5 9.45 12.0 15.0
Nominal biological load BOD5[kg/day] 1.9 2.4 3.0 3.7 4.8 6.0
Range of usage
Number of persons 19 - 38 24 - 48 30 - 60 38 - 76 48 - 96 60 - 120
Hydraulic load [m3/day] 2.8 - 5.7 3.6 - 7.2 4.5 - 9.0 5.7 - 11.4 7.2 - 14.4 9.0 - 18.0
Biological load BOD5[kg/day] 1.14 - 2.28 1.44 - 2.88 1.80 - 3.60 2.28 - 4.56 2.88 - 5.76 3.60 - 7.20

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Operation manual
ACO Clara
3.2 Check of plant type, nameplate
3.3 Cover
The nameplate is placed under the cover on the wall of the bodywork in
accordance with CE certification as per the EN 12566-3 standard.
Legend:
PE – scope of usage, number of equivalent inhabitants
Article Number – serves for identification of size and type
Serial Number – serial number
Power Supply – information on installed electric output
Weight – information on weight
Closing and opening of access cover.
The covers facilitate easy access to the technological parts of the plant.
They are made of glass fiber and are fitted with an ingenious locking sys-
tem that permits easy removal of the cover, together with good protecti-
on in its closed state. The upper part consists of an anti-slip layer and
there is microporous rubber packing preventing smells from escaping
into the vicinity of the plant on the underside. The space between the
upper and bottom layers is filled with polyurethane foam.
Leave the cover open only for the period
necessary for the checking, maintenance
or servicing of the plant.
Never leave the plant with the cover open.
!
The plant cover is only suitable for carrying
the weight of persons.

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Operation manual
ACO Clara
3.4 Inlet and outlet pipes
The plant is supplied with firmly fixed built-in inlet (Pos. 1) and outlet
pipes (Pos. 2) DN 200. The inlet pipe is labeled INLET and the outlet
pipe is labeled OUTLET.
3.5 Air-lift pumps
The pumping of raw water, the recirculation of activated sludge, and the
pumping of surplus sludge are performed by air-lift pumps (Pos. 9, 10, 11).
These pumps work on the principle of a vertical pipe immersed in the pum-
ped liquid, where the air is supplied to the bottom part (beyond the liquid
inlet). This liquid rises upwards because of the difference in liquid densities
between the air in the pipe and the ambient liquid. The liquid flow through
the air-lift pump changes, depending on the level, with the result that a
decreasing level reduces the flow through the air-lift pump.
3.6 Blower
The supply of the volume of air needed for the micro-bubble aeration of
the activation tank and to drive the air-lift pumps is ensured by a lamel-
la/side channel blower situated outside the main tank; see Chapter 5.2.
The blower is connected to the air system by means of a hose and via
connecting pipe (Pos. 12).
The heated air runs in the hose connecting
the blower and the plant, and so a hose resistant
to an increased air temperature must be used.
The blower requires regular maintenance and service;
this is specified in Chapter 9.
Blower specification
Type Type V / Hz Blower input [kW]
of plant of blower maximum actual
AC 19-38 2 x Secoh EL 250 230/50 0,67 0,43
AC 24-48 2 x Secoh EL 250 230/50 0,67 0,43
AC 30-60 Becker DT 4.25 330-440/50 1,10 0,75
AC 38-76 Becker DT 4.40 330-440/50 1,85 0,96
AC 48-96 Becker SV 8.190/2 330-440/50 2,00 0,75
AC 60-120 Becker SV 5.250/2 370-460/50 2,00 1,30
Air distributor
The air distributor (Pos. 13) serves to distribute the supplied air to indivi-
dual devices. The outlets from the distributor and hoses are fitted with
tags and the name of the unit. The necessary air volume supplied to the
individual parts of the plant is regulated by nozzles (excluding aeration).
The nozzles are adjusted by the manufacturer.
No interference with the nozzle layout is
permitted.
!
Legend:
Return sludge – air-lift pump for return sludge
Aeration elements – aeration elements in activation tank
Surplus sludge – air-lift pump for surplus sludge
Raw sewage water – air-lift pump for raw sewage water
The air is heated in the blower. Take increased
care when handling the hose on the outlet side.

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Operation manual
ACO Clara
3.7 Mechanical pretreatment
The mechanical pretreatment is divided into two chambers using a partiti-
on with holes. The first is open to the inlet pipe. Here solids are deposi-
ted and the substances floating on the water surface are trapped. The
pretreated water from the second chamber is pumped by the air-lift
pump for raw sewage water (Pos. 9) to the activation tank, while the
pumped volume is controlled by the backflow box (Pos. 15) at the mouth
of the air-lift pump. The air-lift pump for raw sewage water is protected
against getting blocked by these solid impurities by a scum board.
During operation the buffer tank is gradually
filled up, so that the content of this tank has
to be removed if needed; see Chapter 6.4.11.
Buffer area
The waste water is accumulated in the sedimentation tank during hydrau-
lic peaks in the daily peak period and is pumped gradually to the biologi-
cal part. This ensures that its load is uniformly distributed, which helps to
achieve the excellent purification qualities of the whole plant.
The pretreated water from the second chamber is continuously pumped
by the air-lift pump for raw sewage water (Pos. 9) to the activation tank.
With a higher flow rate through the air-lift pump a part of the water is
returned by overflow to the buffer tank.
Storage accommodation
The air-lift pump that pumps the surplus sludge from the activation tank
during desludging (reduction of activated sludge concentration) is open
to the first chamber. The surplus sludge forms sediment here. With a full
biological load the storage accommodation will be filled up within 100-
150 days.
3.8 Activation tank
The aeration elements (Pos. 8) are placed in the activation tank. These
elements ensure micro-bubble aeration. They are placed in such a way as
to ensure the ideal agitation of the whole space of the activation tank.
The aeration elements are placed on a distribution main which is fixed to
the bottom of the activation tank. Air supply from air distributor (Pos. 13)
is provided by flexible hose.
The activation tank is interconnected with the final sedimentation tank by
the connecting pipe.
The air-lift pump for the pumping of surplus sludge (Pos. 11) leads from
the activation tank to the first chamber of pretreatment.
3.9 Final sedimentation tank
The activated sludge flows through the stilling cylinder into the final sedi-
mentation tank, where the activated sludge is separated from the treated
water by the effect of gravity. The treated water then flows away over
the outlet object (Pos. 14) of the plant by overflow to the outlet pipe
(Pos. 2) and the sedimented activated sludge is pumped from the sludge
sump by the air-lift pump for return sludge (Pos. 10) back to the activati-
on tank.
3.10 Ventilation pipe
It is designed for an air outlet, supplied for the activation and driving of
the air-lift pumps, outside the tank. The outlet of the ventilation pipe (Pos.
3) DN 100 is blocked off with a cap from the factory. For plant ventilati-
on, see Chapter 5.3. The ventilation pipe is marked VENTILATION.

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Operation manual
ACO Clara
4 How the plant works
The ACO Clara waste water treatment plant is a mechanical-biological
treatment plant with a continual flow rate working on the principle of
mixing activation with the gravitational separation of activated sludge
from the treated water in the final sedimentation tank.
The ACO Clara waste water treatment plant consists of mechanical pre-
treatment and a biological part. The mechanical pre-treatment part is for-
med of a primary treatment tank with a buffer area and a storage area.
The waste water enters the ACO Clara unit via the inlet pipe and flows
into the first chamber of the primary treatment tank. Settable solids sink
to the bottom of the tank and floating matter is caught by a scum board
and the sewage water overflows to the second chamber, where the raw
waste water air lift pump is placed. The air lift pump is protected against
blockage by a scum board.
Hydraulic peaks at the inlet of ACO Clara waste water treatment plants
are absorbed in the buffer area. The pre-treated water is then pumped at
a uniform flow rate from the buffer area into the biological part of the
plant. Hydraulic peak equalization increases the stable purification effici-
ency of the plant considerably.
The biological part of the ACO Clara consists of the activation tank and
the built-in final sedimentation tank. The activation tank is aerated by
micro-bubble aeration. The water goes from the activation tank into the
final sedimentation tank, which enables treated water to be separated
gravitationally from activated sludge. The treated water flows out of the
waste water treatment plant through the outlet connection. The activated
sludge sinks to the bottom of the final sedimentation tank, from where it
is pumped back as return sludge and also partly into the storage area as
surplus sludge. The final sedimentation tank is optionally equipped with a
skimmer for the automatic collection and removal of floating sludge from
the water surface. This device can reduce maintenance work during ope-
ration.
Surplus sludge is stored in the storage area, which in fully loaded plants
is capable of holding about 100-150 days’ capacity. The pumping of
sewage water and return and surplus sludge is achieved in the ACO
Clara by using air-lift pumps. These air-lift pumps need no maintenance
and are resistant to clogging. The hydraulic capacity of the air–lift pumps
is continuously adjustable, even at very low flow rates. This helps to
ensure uniformity in the purification process and thus achieve stable puri-
fication efficiency. The only electric part of the ACO Clara is a blower
supplying air to the aeration elements in the activation tank and into the
air-lift pumps.
air
blower
surplus sludge
raw sewage water
sludge return
Key:
1. Pre-treatment
2. Buffer area
3. Storage area
4. Activation tank
5. Final sedimentation tank

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Operation manual
ACO Clara
5 Installation
Before handling it is necessary to ensure the
plant spaces are free of foreign objects and
stormwater and that the cordings on the plant
are sufficiently tight.
The plant can be transported only on a truck with sufficient carrying
capacity and sufficient freight space dimensions. The handling can be
performed using crane. It is necessary to use a beam hanger.
Always handle in a horizontal position with a view to the
strength of the materials used.
For temporary storage of the waste water treatment plant
it is necessary to provide a flat surface with the ground
area of the plant as a minimum area and under conditions
that prevent any mechanical damage.
During long-term storage the plant must not be exposed to solar radiati-
on for longer than 3 months.
5.1 Transport and storage
!
!
!
No handling of the plant should take place
below a temperature of +5°C.
For manipulation with unit always use
a beam hanger.
L
Depending on the location of the blower, it is necessary to ensure a pas-
sage for the hose regarding the power supply to the box for the blower.
A 7-m hose is a part of supply.
It is recommended to run the hose underground at a depth suitable for
connection to the plant. The hose must be protected against ground
pressure; it must not be pressed down or broken (connect this hose to
the pipe sleeve).
During the preparation for installation it is necessary to provide either a
power supply to the blower or a passage for the inlet hose, depending
on the location of the blower.
The blower should be situated up to 7 m from the plant. In the event of a
greater distance please contact the manufacturer.
5.2 Installation of blower
The air supplied to the plant by the blower must be ventilated to an out-
door space. The ventilation is provided by the ventilation pipe DN 100,
which must be opened above ground.
The ventilation pipe must terminate at a sufficient height
above ground for it to be above snow level during
the winter period.
In some cases the plant can be ventilated by inlet or outlet pipes. Then
the ventilation pipe can remain unused.
5.3 Plant ventilation
The construction work must be performed as a project of an authorized
design organization.
A supply of service water in a minimum quantity corresponding with the
operating volume of the plant volume and an adequate handling area
must be provided during installation.
During the operation of the plant a handling area of at least 1m must be
provided around the plant.
A traffic load and any other load on the
surroundings of the plant are allowed at
a distance of 3 m from the tank wall.
Both the plant covers and the ground above the plant itself can bear a
load of up to a maximum of 2,5 kN/m2.
5.4 Construction requirements
!
ACO Clara 19-38 24-48 30-60 38-76 48-96 60-120
L [mm] 1810 2050 2050 2200 2390 2800
in object
in plastic box
Blower location:

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Operation manual
ACO Clara
Installation in the ground
The ACO Clara waste water treatment plant is designed as a self-suppor-
ting plastic tank for installation in a ground bed without any concrete
encasement.
The procedure for embedding the plant in the
ground described below is intended for the
installation of the inlet pipe to a depth of 0.8 m
and must not be used for impervious soil or if the
level of underground water is above the level of the base
plate or if the plant is situated on a slope steeper than 10%.
Installation procedure:
1. Excavation of foundation pit – the subsoil must not be loosened by
extraction. If necessary it will be compacted so as to correspond with
compact natural material.
2. Concreting of base plate – the tank will be laid on a concrete reinfor-
ced plate thickness min. 150 mm with a flatness of ± 5 mm/m. No
irregularities must occur between the tank bottom and the plate.
3. Placing plant into foundation pit – The pit must be excavated in such a
way that after the concreting of the base plate and emplacing the
plant the upper edge of the cover will be approx. 70 mm above
ground level.
4. Connect the: inlet pipe
outlet pipe
hose from the blower
ventilation line (if needed)
5. Filling with water – gradually fill the entire interior of the plant with
water up to 1 m.
6. Backfill – the backfill must be done in single layers with a maximum
thickness of 400 mm thick all round the plant perimeter together with
compaction. The compaction grade is calculated to be between
90–92% Pgs.
7. Gradual filling of tank with water – gradually fill the tank with water
and backfill the surroundings of the plant. A water level ca. 300 mm
above the backfill level must be permanently kept in all parts of the
tank.
8. Gradual backfill – proceed with tank backfill acc. to item 6.
9. As soon as the water level in the waste water treatment plant reaches
the level of the outlet pipe, the remaining backfill is done without addi-
tional filling up with water.
10. Proceed with backfill up to ground level.
Installation procedure:
!
!
5.5 Electrical installation
1. Excavation of building pit 2. Laying of base plate
3. Plant location 4. Connection of branches
5. Start of filling with water 6. Start of backfill
7. Gradual filling with water 8. Gradual backfill
9. Filling with water up to outfall 10. Gradual backfill up to ground
level
After completion of backfill leave the tank
filled up with water.
5.5.1 1 phase motor
The plant connection arrangement consists of the connection of the blo-
wer to a socket with an earth pin powered from 1/N/PE AC 230V/50Hz
mains installed as per national safety standards and regulations on blo-
wer space. The recommended socket protection is via a 10A char.B cir-
cuit breaker. A revision will be made to the socket according to the
appropriate national standards and regulations.
5.5.2 3 phase motor
The plant connection arrangement consists of the connection of the blo-
wer to a switchbox powered from 3/N/PE AC 230V/50Hz mains installed
as per national safety standards and regulations on blower space. The
recommended protection of the blower is via motor-circuit breaker which
is sized according to rating plate value. A revision will be made to the
cable according to the appropriate national standards and regulations.
While using of blower with 3 phases engine to
check proper engine rotation (rotation arrow is
on the body of blower).
!

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Operation manual
ACO Clara
6 Operation and maintenance instructions
If the time taken for installation and plant commissioning
is too long and the water quality drops significantly
(turbid water, smell), it is recommended to drain the
tank and fill it up again with clear service water.
Check before connection
Check if the tank is filled up with water up to the outlet pipe.
Check the proper state of all plant parts (air-lift pumps, electrical conne-
ction, hoses etc.)
Check the right electric connection of blower
While using of blower with 3 phases engine to
check proper engine rotation (rotation arrow is
on the body of blower).
• Disconnect hose between the unit and the plant.
• Switch the blower on and check air flow. If no flow is detected with air
being sucked into the blower, change phase position.
• Reconnect hose between blower and air jet.
Functional check
When connecting to the mains check the functioning of the blower and
air-lift pumps and the aeration of the activation tank acc. to Chapter 6.4.
After the functional check you can start feeding in the waste water.
Initial plant operation
To reach the proper purification effect the concentration of activated
sludge in the activation tank must be in the range of 3-6 kg/m3.
After the plant has been put into operation the concentration of activated
sludge gradually increases. With a correct plant load the required con-
centration is reached within 4-8 weeks.
During the initial operation of the plant the full
purification efficiency is not reached.
During the initial operation of the plant check
the concentration of activated sludge weekly
by means of a sedimentation test.
During the initial operation of the plant foam can occur on the water sur-
face in the activation tank because of the presence of e.g. cleaning
agents in the waste water. This foam will disappear when the correct
concentration of activated sludge is reached.
Filling up with activated sludge from another waste water
treatment plant
To reach full plant efficiency it is possible to use activated sludge from
another properly functioning plant.
Pump out the water from the activation and final sedimentation tanks and
fill them with activated sludge. You will find the required quantity in the
following table.
ACO Clara 19-38 24-48 30-60 38-76 48-96 60-120
Required volume of the
activated sludge [m3] 3,2 4,0 5,0 6,5 8,0 10,0
After filling up with activated sludge check
the concentration of activated sludge by means
of a sedimentation test.
Follow all procedures in accordance with the occupational safety instruc-
tions described in Chapter 2.
6.1 Plant commissioning
A operation journal with records of regular activities such as inspections,
maintenance work, repairs, revisions, service work, sediment value, and
operating conditions, as well as events, is part of every ACO Clara plant.
The non-keeping of the operation journal is cons-
dered as improper operation resulting in a loss of
the right to claim repairs under the guarantee from
the manufacturer during the guarantee period.
6.2 Records of plant operation
The following list of things will enable you to operate and maintain the
plant correctly and comfortably.
• Rubber gloves
• Protective clothing
• Graduated 1000-ml cylinder (to be supplied)
• 1000-ml bottles for sampling
• Sampling scoop with handle
• Brush with handle for cleaning of air-lift pumps
6.3 Accessories for plant operation
!
!
!
If the following procedures are not followed
the plant will not work correctly.
By sucking of water inside the blower will
occur a critical damage of the blower.

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Operation manual
ACO Clara
This chapter provides information on the checking process and describes
the state in which the plant is in good technical and operating condition.
The troubleshooting is described in the following chapter, Chapter 7.
The procedure for the performance of individual activities is described in
following chapters.
Perform all activities in accordance with the occupational
safety instructions described in Chapter 2.
6.4 Description of individual checks and maintenance work
Visual check of plant
6.4.2 Aeration in activation tank
If properly aerated, air bubbles with a size of ca. 3-10 mm occur in whole
area of water surface in the activation tank. If the activated sludge is in
good condition, no surplus foam is developed. The level of the activation
tank must not be filled up with too great a volume of foam.
6.4.1 Check of blower function
The blower is in continuous operation. For that reason any
breakdown is a fault state.
The blower can be checked simply by a listening test of whether the engi-
ne is producing a sound. Whether the aeration of the activation tank is
occurring can be checked visually.
List of maintenance tasks and checks
Interval Activity Description Chapter
daily Check of blower function Engine sound is heard, visual check of aeration of activation tank 6.4.1
weekly Visual check of plant Aeration in activation tank 6.4.2
Function of air-lift pumps 6.4.3
Water level of sedimentation tank, inlet pipe 6.4.4
Water level of final sedimentation tank 6.4.5
Quality of treated water 6.4.6
2 weeks Check of activated sludge Sedimentation test 6.4.7
monthly Check of blower filter As per manual for blower 9
Check of treated water Sampling; water must be clear and without smell 6.4.8
4 months Discharging of condensate water from aeration system 6.4.9
Check of lamellas in blower, only AC 30-60 and AC 38-76 As per manual for blower 9
if needed Removal of surplus sludge As per result of sedimentation test 6.4.10
Discharge of storage tank As per sedimentation test 6.4.11
Cleaning of walls of tanks 6.4.12
Cleaning of air-lift pumps 6.4.13
18 months Replacement of lamellas/membranes As per manual for blower 9
in blower, no for AC 48-96 and AC 60-120
5-8 years Replacement of aeration elements As per visual check of aeration in activation tank 6.4.14
Changing of bearings in blower, no for AC 19-38 and AC 24-48 Authorized company
Any blower breakdown longer than 24 hours
will seriously damage the activated sludge.

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Operation manual
ACO Clara
6.4.3 Functions of air-lift pumps
The air-lift pumps for the pumping of raw sewage water
and the air-lift pump for the pumping of return sludge are
in continuous operation.
Air-lift pump for raw sewage water: the capacity of the air-lift pump
depends on the level of the sedimentation tank. If the volume in the
balancing chamber is not fully drained, then the waste water has to be
pumped to the activation tank.
We identify the choking of the air-lift pump as per continuous maximum
level in the primary sedimentation tank, together with waste water overf-
low to the activation tank via the by-pass pipe.
Air-lift pump for return sludge: The air-lift pump must be permanently
in operation with the constant flow rate set by the manufacturer.
The inactivity of the air-lift pump for return
sludge will seriously damage the entire
purification effect of the plant within 24 hours.
6.4.4 Tank Level of Mechanical Pretreatment,
Inlet Pipe
The inlet pipe must be free of all impurities.
There must be the same water level in all chambers. Sediment of solids
can develop in the first chamber. We recommend loosening it by means
of a stream of water.
The water level beyond the scum board, where the air-lift pump for the
pumping of raw sewage water is, must be free of gross impurities that
could cause it to clog.
Check the state of filling the tank with sediment.
If the sediment level in the tank reaches the level of the edge of the
overflow to the air-lift pump for raw sewage water it is necessary to
pump the whole tank volume immediately. It will become evident because
of the air-lift pump for raw sewage water pumping sewage water with a
high concentration of black digested sludge in the event that the air-lift
pump is clogged.
6.4.5 Level of Final Sedimentation Tank and
Outlet object
Floating sludge can occur on the surface of the final sedimentation tank.
When a higher quantity has accumulated this sludge can build up into a
continual layer with a thickness of ca. 10 cm. This layer does not need
to cause the quality of the treated water to deteriorate, but it makes it
impossible to perform a visual check of the final sedimentation tank.
Therefore it is necessary to remove it.
The outlet of the plant must be free of any sediment, matted material, or
other impurities.
6.4.6 Quality of Treated Water
Check the quality in the outlet of the plant, where the treated water
should be clearly visible without any floating impurities (e.g. flakes of
activated sludge).
!
6.4.7 Check of concentration of activated
sludge – sedimentation test
To perform the test you need a graduated cylinder with a volume of
1000 ml (to be supplied).
The sedimentation test manages to define simply an approximate con-
centration of activated sludge.
The activated sludge must not be grey or black in colour.
The correct colour is brown.
Procedure:
• In accordance with Section 6.5 put a sample of 1000 ml of activated
sludge from the activation tank into the graduated cylinder (the aerati-
on must be running in the activation tank).
• Put the graduated cylinder on a flat surface and wait for 30 minutes.
• Observe the boundary line between the settled sludge and separated
water after 30 minutes.
300ml
600ml
1l
300ml
600ml
1l
300ml
600ml
1l
300ml
600ml
1l
300ml
600ml
1l
300-600 ml, optimal concentration
of activated sludge
shows the proper concentration. No
removal of surplus sludge is required.
0-300 ml, low concentration of activated sludge
means an insufficient concentration of activated sludge
in the activation tank.
600 ml and more, high concentration of activated
sludge
means that there is too high a concentration of activa-
ted sludge in the activation tank and the surplus sludge
should be removed.
No activated sludge in sample
No activated sludge has developed. Such a state can
be considered as a natural one during initial plant ope-
ration or it can show improper plant operation.
No sedimentation of activated sludge
If no boundary line has developed between the sedi-
mented sludge and separated water, this means that
the activated sludge is not in good condition and has
bad sedimentation qualities. It could be a natural pro-
cess during the initial operation of the plant or could be
due to an incorrect load and eventually the occurrence
of too high a quantity of unsuitable matter on the inlet
side (disinfecting agents, toxic substances, acids etc.).
6.4.8 Check of Treated Water
Sample the treated water from the outlet object of the plant to a speci-
men holder with plain walls. The treated water should be free of undissol-
ved substances (e.g. flakes of activated sludge) and not be significantly
coloured or have a strong smell.

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ACO Clara
6.4.10 Discharging of Surplus Sludge
Improper or wrongly performed removal of sludge
can cause a reduction in the concentration of
activated sludge below the optimal level and thus
cause a temporary reduction in the efficiency of
purification.
When should the removal of sludge be performed?
The removal of sludge is carried out if we find a higher-than-optimal concent-
ration of activated sludge. During the sedimentation test the boundary line
value of sedimented sludge and separated water is higher than 600 ml.
The interval between one removal and the next depends on the actual condi-
tions in which the plant is being operated. This interval can range between
2-16 weeks as low-loaded plants have a longer desludging interval than
highly loaded ones.
How to remove the sludge?
The removal is carried out with the air-lift pump for the removal of surp-
lus sludge, which is activated by opening a cock on the air valve.
close position open position
Leave the cock open for 4-8 hours as per initial concentration and conti-
nuously check the concentration of activated sludge by means of a sedi-
mentation test. You will complete the sludge removal by closing the cock
after reaching the value of 300 ml.
In the course of sludge removal the aeration intensity can be reduced, as
can the output of the other air-lift pumps.
6.4.9 Discharging of condensate water from
aeration system
Condensate water is discharged by air pressure in aeration system by
opening the valve placed above activation tank.
Let valve opened until the water is coming out of valve.
Alternative solution
The removal of surplus sludge can be carried out by draining a partial volu-
me of activated sludge with a sludge pump external to the plant (to be used
for the initial operation of another plant, putting in a sludge removal truck and
carrying away for disposal, etc.).
The maximum quantity of pumped sludge depends on the actual concentrati-
on as indicated by the sedimentation test. After pumping a partial volume of
activated sludge and filling up with waste water the boundary line value of the
settled-down sludge and separated water must not to lower than 300 ml.
6.4.11 Discharging of mechanical
pretreatment tank
Perform the sludge draining by means of a sludge removal truck.
The minimum distance between the tank and the
wheels of the sludge removal truck is 3m.
Coming closer could lead to the deformation of the
plant tank caused by the pressure of the weight of
the truck, with the possibility of total collapse.
Procedure:
• Turn off the blower.
• Insert a suction basket into the bottom of the tank and pump out the
sediment. When pumping, if the sludge is too heavy perform the pum-
ping gradually from one and then from the other chamber of the sedi-
mentation tank.
• Fill up the tank with fresh water after pumping out all the content.
• Turn on the blower.
6.4.12 Cleaning of tank walls
Clean with a brush or fresh water jet.
6.4.13 Cleaning of air-lift pumps
During plant operation the air-lift pumps can become clogged or even
choked if not maintained properly.
Remove the top part of the air-lift pump and clean its interior with a
brush with a handle.
!
!
!
The blower must be turned on during sludge
removal.
The sludge must be handled in compliance with
legal regulations.
When handling the suction hose take care to
prevent damage to the interior of the tank.
Make sure that the clock is closed after
the removal of sludge.

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Operation manual
ACO Clara
6.4.14 Replacement of aeration elements
The working life of the aeration elements is 5-8 years.
Do not use other types of elements than those approved by
the manufacturer.
The aeration elements are placed on a distribution main which is fixed to
the bottom of the activation tank.
To replace the aeration elements it is necessary to pump out the whole
activation tank and final sedimentation tank volume. It is also recommen-
ded to clean away any remaining sediments.
Before pumping out the volume of the activation tank it is
recommended first to drain the mechanical pretreatment
tank and to use it for the storage of activated sludge.
Leave the activated sludge without aeration for a maxi-
mum of 24 hours.
When the replacement of damaged aeration elements is
carried out it is recommended to do a replacement of all
elements in activation tank and air supply hoses as well.
Replacement procedure:
• Turn off the blower
• Pump out the water from activation tank and final sedimentation tank in
a way to leave app. 150 mm water above the elements (app. 350 mm
from the bottom of the tank)
• Turn on the blower
• Visually check all aeration elements
• Turn off the blower
• Discharge the rest of water
• Unscrew the element(s) in an anticlockwise manner
• Check the cleanliness of the connection
• Provide the connection thread with sealing (e.g. teflon tape)
• Screw in the new element in a clockwise manner
• Fill the activation tank and the final sedimentation tank with water in a
way to have app. 150 mm water above the elements (app. 350 mm
from the bottom of the tank)
• Switch on the blower
• Visually check all aeration elements
• Fill the activation tank and the final sedimentation tank with water (acti-
vated sludge) up to maximum level.
• Visually check the aeration described in Chapter 6.4.2
Sampling and its consequent analysis in an accredited laboratory are the
only conclusive way to evaluate the efficiency of the plant.
When sampling follow the procedures defined by the individual regulati-
ons which are prescribed for the given type of analysis (size of sample,
method, maximum period of storage, etc.).
Using contaminated sampling bottles or tools
(scoop, etc.) for sampling can influence the results
of the analysis. Therefore, before sampling wash
the sampling bottles and all other tools coming
into contact with the sample thoroughly.
If not specified otherwise, keep the obtained sample in a cool and dark
place for a maximum period of 24 hours.
6.5.1 Sample at inlet
It is recommended to sample directly under the inlet pipe or shaft on the
inlet sewer system.
6.5.2 Sample at outlet
Take sample directly from the outlet of the plant in the final sedimentati-
on tank using a scoop or directly to a sampling bottle.
6.5.3 Sample of activated sludge
Take always sample from the activation tank, provided that the blower is
running for a minimum of 1 minute.
6.5 Sampling

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Operation manual
ACO Clara
The means of purification using activated sludge requires a steady flow
of waste water containing organic substances that represent nutrition for
the organisms in the activated sludge. The absence of nutrients for these
substances can result in the so-called starvation of the activated sludge
and the collapse of the whole biological system.
6.6.1 Short-term operational constraints
Short-term operational constraints (holidays etc.) are to be understood
as a reduction or shutdown of the waste water inflow to the plant for a
period not longer than 25 days. No significant reduction in the quality of
the activated sludge occurs within the first 10 days, but with longer ope-
rational constraints the quality of the activated sludge gradually deterio-
rates up to full “starvation“. This “starvation” will occur after approximate-
ly 8 weeks. The capacity of the plant is then completely lost and it must
be allowed to resume work again after a fresh commencement of opera-
tion as specified in Chapter 6.1.
Leave the plant to work during short-term operational constraints.
6.6.2 Long-term shutdown
Long-term plant shutdown is to be understood as being for a period lon-
ger than 8 weeks.
During long-term plant shutdown turn off the blower, pump out all the
plant content (sedimentation tank, activation tank and final sedimentation
tank) according to Section 6.4.11, and fill it immediately with water.
After putting the plant back into operation again, it must be allowed to
start work again as stated in Chapter 6.1.
6.6 Plant breakdown

Fault Possible cause Remedy procedure
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Operation manual
ACO Clara
An overview of possible faults of the technological plant equipment and
how they can be remedied can be found in the following table:
7 Troubleshooting
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Blower does not work (no
motor noise).
Blower undercapacity (weak
aeration of activation, underca-
pacity of air-lift pumps).
Inadequate aeration of activati-
on (visually weak intensity of
tank agitation), or irregular
bubbles, but air-lift pumps are
running.
Some air-lift pumps do not
work.
The air-lift pump for pumping
raw water from the pretreat-
ment does not work repeatedly.
The plant smells strongly.
Repeated occurrence of floating
sludge in final sedimentation
tank.
The plant does not reach the
required purification efficiency.
The escape of flakes of activa-
ted sludge from the final sedi-
mentation tank to the outlet.
During sedimentation test no
deposit of activated sludge
occurred.
During sedimentation test no
sludge occurs in sample.
Abnormal occurence of foam on
water in activation tank.
Failure of circuit breaker for connection.
Disconnected or faulty socket for connection.
Faulty blower.
Clogged blower filter.
Disconnected air supply to air distributor, air-lift
pumps or aeration elements.
Blower defect (abnormal wear of membrane/lamella,
defect of blower aggregate).
Aeration elements and distribution line filled up with
condensate.
Fault of aeration elements.
Disconnected or clogged air supply to air-lift pump.
Clogged nozzle of air supply to air-lift pump.
Clogging of air-lift pump.
The layer of sludge in the sedimentation tank is so
high that the sludge overflows the partitions to the
air-lift pump.
Wrong function of ventilation of inner plant space.
Inadequate function of ventilation unit.
The plant is loaded with waste water above the
design value.
Other causes.
No observing of instructions for operation and main-
tenance (high concentration of sludge in activation
tank…).
Other cause.
Failure to observe instructions for operation and
maintenance.
Other causes.
The plant is hydraulically overloaded.
Result of inflow of harmful substances.
Other causes or failure to follow instructions for
operation and maintenance.
Result of inflow of harmful substances.
High concentration of activated sludge.
Other cause.
Low concentration of activated sludge.
The sludge was not developed because of low plant
load.
Other cause.
Result of inflow of harmful substances.
Increase of fibrous organisms.
Switch on the circuit breaker.
Reconnect the socket or ensure specialized repair.
Ensure specialized repair of blower – see Chap. 9.
Clean the blower filter – see Chap. 9.
Repair the line for air supply.
Ensure specialized repair of blower – see Chap. 9.
Make condensate outlet. If the condensate outlet
cannot be made or ensured, remove aeration ele-
ments and check them – see Chap. 6.4.14.
Replace aeration elements – see Chap. 6.4.14.
Repair the line for air supply.
Clean the nozzle.
Clean the air-lift pumps – see Chap. 6.4.13.
Pump the sludge from the sedimentation tank – see
Chap.6.4.11 and clean the air-lifts – see Chap.
6.4.13.
Provide ventilation for the inner plant space – see
chap. 5.3.
The same procedure as in faults 2 and 3.
Ensure technical expertise of qualified worker.
Ensure technical expertise of qualified worker.
Observation of instructions specified in Section 6.
Ensure technical expertise of qualified worker.
Observation of instructions specified in Section 6.
Ensure technical expertise of qualified worker.
Check the functioning of the air-lift pump for raw
sewage water. Find the source of the abnormal
supply of waste water.
Eliminate inflow of harmful substances, ensure tech-
nical expertise of qualified worker.
Ensure technical expertise of qualified worker.
Eliminate inflow of harmful substances; ensure tech-
nical expertise of qualified worker.
Observe instructions for removal of surplus sludge;
see Chap. 6.4.10.
Ensure technical expertise of qualified worker.
Observe instructions for removal of surplus sludge;
see Chap. 6.4.10.
Minimal mass load on plant makes 40% of designed
capacity.
Ensure technical expertise of qualified worker.
Eliminate inflow of harmful substances, break up the
foam with a stream of water.
Break up the foam with a stream of water, ensure
technical expertise of qualified worker.

20
Operation manual
ACO Clara
During long-term testing as per EN 12566-3 in an accredited
laboratory the following average values were achieved:
BSK5.................9.5 mg/l
CHSK ................59.0 mg/l
NL ....................16.4 mg/l
N-NH4 ...............2.1 mg/l
Guaranteed average values for nominal hydraulic and biological
loading is:
BOD5................25 mg/l
COD..................90 mg/l
TSS ..................35 mg/l
N-NH4 ...............10 mg/l - for temperature 12°C
8 Certification