Calculation of domestic supply water plant capacity 400m3day

4 Construction works Scale of construction work of water supply system in Thanh Thach commune, Tuyen Hoa district, capacity 400 m3day 4 1 Inlet construction work The inlet and pumping station level I. The raw water pipeline is responsible for transporting water from the dam to the treatment plan. Design 01 raw water pipeline from the foothill (at elevation +35.70m) to the water treatment plant located in the high hill area (the location of the treatment cluster is at the elevation of +65.50m). Raw water pipeline design with working capacity 400 m3day. The treatment plan works 2024h, so the raw water pipe works 2024h with 1 mode.

4 Construction works

Scale of construction work of water supply system in Thanh Thach commune,Tuyen Hoa district, capacity 400 m3/day

4.1 Inlet construction work

The inlet and pumping station level I (raw water pumping station), capacity

20 m3/h, located in Gianh river, the foothill area, 60m from the construction site ofthe water plant Building elevation +35.70m; pit structure by M250 reinforcedconcrete Install 02 submersible pumps operating alternately 20/24 hours,supplying water to the treatment cluster at the water plant area

4.2 Raw water pipeline:

a) Design plan:

The raw water pipeline is responsible for transporting water from the dam tothe treatment plan Design 01 raw water pipeline from the foothill (at elevation+35.70m) to the water treatment plant located in the high hill area (the location ofthe treatment cluster is at the elevation of +65.50m) Raw water pipeline designwith working capacity 400 m3/day The treatment plan works 20/24h, so the rawwater pipe works 20/24h with 1 mode

b) Hydraulic calculation of raw water pipeline:

- Water plant capacity: 400 m3/day

- Operating time t=20h

- Flow of pump: 20m3/h=0.005556 m3/s

- Hazen Williams coefficient: C=140Unit loss: i=6.824*(v/C)^1.852*D^(-1.167)=0.0193

1000i=19.3m/kmRaw water pipe length: 60m

 Loss along the pipeline: Hdd=19.3*0.06=1.158m

 Local loss: Hcb=v2/2g*C=1.5m

Residual pressure at treatment system: 6m

Level difference: 40m

 Required pump head: 48.658m Choose Hđ=50m

4.3 Cluster of Mixing tank, cylindrical vortex reaction tank, vertical settling, rapid filtration:

The treatment system with a capacity of 400m3/day includes:

4.2.1 Static mixer

The requirement is that the static mixing has enough strength to mixchemicals, ensuring that the chemicals are evenly dissolved in the raw water beforebeing distributed to the filter settling cluster, avoiding the uneven mixing ofchemicals leading to effective low processing, wasted chemical consumption.Static mixer equipment is designed with the following parameters:

- Dimension DxH: 150x1000 mm;

- Material: Inox SUS 304;

- Connection by flange BS4504 DN80;

- Hydraulic loss: 0.06 meters of water;

- Mixing intensity is 460 gradient (make sure the mixing intensity is in therange of 200-1000 gradient);

4.2.2 Lamella settling tank

Lamella settling tank has an operating capacity of 20m3/h

According to article 6.66 and formula (6-9) TCVN 33-2006, the horizontalarea of the settling tank is calculated according to the following formula:

- q: Flow of water in m3/h q = 20 m3/h

- a: Surface load of the settling tank for less turbid water is taken from 3-3.5

m3/m2.h; for medium turbid water taken from 3.6-4.5 m3/m2.h and for more turbidwater from 4.6-5.5 m3/m2.h

Choose a tank diameter of 2.4m

The settling tank height includes the sludge reservoir height, the suspendedsediment height, the lamellar sediment height, the safety water layer height and thevortex reaction height The height of the settling tank is 6.4m

- Dimension of settling tank: DxH=2.400x6.400mm

- Material: SS400 steel with 3 layers of epoxy coating

- Accompany with:

+ Lamella settling plate, water collection trough

+ Railing, galvanized steel SS400 working floor

4.2.3 Self-cleaning Gravity Filter

Design capacity of treatment system: 20 m3/h

The required filter tank area is: V = 20/8 = 2.5 m2

Choose a fast filter tank filtration speed v = 8 m/h The filter sand layerthickness is 0.6-1mm

To increase structural durability and conform to technology, choose a roundcylindrical tank

The required diameter of the tank is: V = 3.14 * D2/4 => D = 1.78m

The thickness of the filter material layer is 1-1.2m (according to section 7.8

"Book of water treatment for domestic and industrial use" - Trinh Xuan Lai)

Choose h = 1 m

The volume of filter media layer is: V = 1*1.8*1.8*3.14/4 = 2.54 m3

Volume of sludge container Vsludge = 38% Vfilter = 0.96 m3

The height of the filter is: H = 0.45 + 1+ 1.05+2.0 = 4.5 m

In which:

- Height of the bottom of the filter floor: 0.45 meter

- Height of filter sand layer: 1 meter

- Safe water layer height Backwash water tank: 1.05+2= 3.05 meter

- Dimensions of open backwash gravity filter tank with siphon: DxH =1,800x4,500 mm

- Material: SS400 steel with 3 layers of epoxy coating

- Accompany with:

+ Filter cap, filter sand

+ Railing, galvanized steel SS400 working floor

 Calculation of the filtering process

Backwash tank volume Vbackwash= 2 x (1.8x1.8x3.14/4)= 5.1 (m3)

Filter media size: 1-2 mm, heterogeneity factor is 1.5 mm

Rinse the filter with water stored on the backwash tank When washing thefilter, there is water on the surface washing water intensity is 6-8 m3/m2.h(according to section 7.8 "Book of water treatment for domestic and industrial use"

- Trinh Xuan Lai) Washing time 5 minutes

The volume of water to be washed and filtered is: Vwash= 2.54 *6*5*60/1000

= 4.57 (m3)

From the above we have Vbackwash ≤Vwash

So the device meets the filter washing process

- The filter settling system is protected in SS400 steel structure, 3-layer epoxycoating

- Output water after treatment meets QCVN 01:2009/BYT National TechnicalRegulation on drinking water quality and QCVN 02:2009/BYT National TechnicalRegulation on domestic water quality

4.4 Chemical house, combined with operator shift:

The chemical house is a place to dosing and mixing chemicals in the process

of settling, filtering and disinfecting water The items in the chemical houseinclude:

a) Chemical coagulant PAC

- PAC mixing tank: 01 plastic tank, tank capacity: Wh = 0.5 (m3)

- SUS 304 stainless steel stirrer: 01 set

- Mixing device: stirring motor Power N = 0.75 kW

+ Select the number of rotations of the propeller: 30 rpm

+ Propeller length is taken as: 0.45 x d = 0.45 x 0.8 = 0.36 (m)

- Dosing device: Dosing pump

+ Flow of pump: 28 l/h

+ Head pressure: H=30m

+ Power 14W

b) Chemical flocculation: polymer

- Polymer mixing tank: 01 plastic tank, tank capacity: Wh = 0.5 (m3)

- SUS 304 stainless steel stirrer: 01 set

- Mixing device: stirring motor Power N = 0.75 kW

+ Select the number of rotations of the propeller: 30 rpm

+ Propeller length is taken as: 0.45 x d = 0.45 x 0.8 = 0.36 (m)

- Dosing device: Dosing pump

+ Flow of pump: 28 l/h

+ Head pressure: H=30m

+ Power 14W

- Chemical warehouse

+ Chemical reserve is about 3.00 tons/15 days

+ Warehouse floor area: 1.98m2

b) Chlorine disinfection:

Disinfect water with liquid chlorine Expected chlorine dosage is 1-3g/m3 of

water; On days when the water supply system is in normal operation, the dose of1g/m3 is used When there is an epidemic or when cleaning pipes, use the dose of2g/m3.

The capacity of chlorination is calculated by the formula: P = Q * CLmax =

20 * 2 = 40 g/h

Q: Treatment water flow, Q= 20 m3/h;

CLmax: The largest amount of chlorine added to the water, CLmax = 2g/m3.Amount of chlorine used for 1 day: M = 400*2/1000 = 0.8 kg/day

With the amount of Active Chlorine needed in one hour: 33.33g/h

Disinfectant chlorine injection system includes:

- The metering pump has Q = 28 l/h 3Bar pressure; P=14W Including 02machines: 01 active machine and 01 standby machine

- 500ml composite tank

- Stirring motor

- SUS 304 stainless steel stirrer: 01 set

The chemical house is built at the windward end to store chemicals and installequipment for mixing and dosing chemicals

The chemical house has a water supply, electricity supply and ventilationsystem The size of the chemical house is 7.8m*11.4m, 3.6m high Reinforcedconcrete floor frame, brick wall with only XM grade 75 mortar The roof floor ispoured with reinforced concrete, tiled with heat-resistant bricks and covered withXika waterproofing layer Finished ceramic tile floor Arrange water supply anddrainage systems, daily-life electricity supply, synchronous lighting

In the chemical house, 01 room is arranged and there is a separate toilet area

to place control cabinets and staff on duty

4.5 Clean water tank:

a) Calculation of tank capacity:

The capacity of the clean water tank is determined according to the workingmode of the raw water pipeline of the level 2 pump

Raw water pipe works of raw water pipes 24/24 hours a day with a regime of4.17% Qday

Level 2 pump is fitted with a frequency converter, so the mode is controlledaccording to the water demand of the water supply network

Graph of water demand for the corresponding water supply network K hour = 1.8

Calculation table of tank capacity

Tank inletflow

(%Q)

Tankoutletflow(%Q)

Waterflow intank (%Q)

- Storage tank capacity:

Wstorage tank = (Qday max ) x (19.57% + 4% backup) = (520 )*23.57% = 122 m3

- Water reserve capacity for the treatment plan of the tank and other factors:

Wtreatment plant = 20 m3.

Total storage tank capacity calculated:

Wtank = Wstorage tank+ Wtreatment plant = 122 + 20 = 142 m3

Design tank capacity 150 m3

b) Design plan of storage tank:

The tank is designed with the size of 10.0 m x 6.0 m, the height of 3.0 m.The tank is placed semi-submersible, designed with reinforced concrete- M250with 250mm thick wall, 250mm thick M250 crushed stone BT bottom, 150mmthick reinforced concrete-M250 lid, a layer of soil 30cm thick on the top of thetank strip, planting insulation grass

4.6 Sludge drying bed.

The water and sludge from the settling tank and filter tank before beingdischarged into the water source are taken to the sludge drying bed The sludge iskept in the sludge drying bed, the water is discharged into the water source,overflows and self-infiltrates into the soil after being treated satisfactorily Thesludge drying bed is designed with 1 compartment

- Basic size of each compartment: LxB = 6.6x15.00m

- Surrounding wall structure: 300 thick stone masonry, brick wall, concreteslab bottom

4.7 Power supply for Treatment plant:

- 11 BC (18:21)-2006 Regulation on electrical equipment

- TCVN 4086-95 Electrical safety in construction

- System of international standards: (IBC, IEC, BS, EIA, IEE, NEC, )

4.7.2 Calculation of required load

a - Lighting calculation formula:

E = (lux)

In which : E : The illuminance of the lamp.

 : The luminous flux of the lamp.

S : Area of use.

With average illuminance on the plane from 100-300 (lux)

b - Formula for calculating power and wire cross-section:

Calculating capacity according to the number of equipment installations andrated power:

n: Number of devices that are the same.

P đm : Rated power of the device.

c Formula for calculating current consumption:

* Single phase voltage:

* 3 phases voltage:

In which :

P tt : Power Consumption (W).

I tt : Amperage (A).

cos  : Power factor.

d The formula for selecting the conductor cross-sectional area is according to the expression:

* Select the cross-section according to the allowable line I cp :

- In case the electrical circuits are not buried underground:

In which:

I TT : Calculated current.

I cp : Permissible long-term current for wire or cable cross-section.

K 4 : The adjustment factor represents the effect of the installation (K 4 =1).

placed side by side (K 5 =0.7).

4.7.3 Power supply plan.

a Power supply source.

The power supply for the building is sourced from the general electricitygrid of the area to supply for the works

three-installed in floor electrical cabinets, room electrical cabinets, area electricalcabinets The general distribution electrical cabinets, floor electrical cabinets arearranged with measuring devices.

In working areas, function rooms, etc., sockets are arranged to serve stationary electrical loads, wall sockets are installed 0.4m from the floor

non-In the living quarters, sockets are installed underground at a height of 0.4mabove the floor, sockets are located in positions suitable to the interior of thebuilding

Electrical cabinets and boxes are installed 1.3m from the finished floor Thewall switch is 1.25m from the finished floor; wall sockets are 0.4m from thefinished floor, in the bathroom, wall sockets are 1.2m from the finished floor

In the working rooms, electrical cabinets are installed including separateprotective circuit-breakers for each type of load such as lighting protection circuit-breakers, sockets, kettles, air conditioners, specialized medical equipment

Protection includes two types: timed overload protection and instantaneoustripping short circuit protection

- ATMs must have an adjustment range from 0.6-1In

- ATMs must have instant cut off button

- Full set of terminals, insulating plates separating the phases on both sides.The floating or sinking electrical wires are protected by plastic pipes or steelpipes, the connecting and intersecting wires must use junction boxes and conduitboxes

To control the pump at the raw water pumping station, install a water levelsensor at the 150m3 tank, combined with a switch relay 02 pumps at the raw waterpumping station are controlled alternately through the pump control cabinet

4.7.4 Lightning protection system and safe grounding:

a Design basis

Based on current lightning protection standards as follows:

- 20 TCN 46-84 lightning protection standards of the Ministry ofConstruction

- NF C17-102/1995 French national safety lightning protection standard

- UNE 21186 Spanish national lightning safety standard.

- TCXDVN 46: 2007 lightning protection standards for construction works

in Vietnam

b Electrical safety grounding system:

- Similar to the lightning protection grounding system, but because therequirements of the electrical safety grounding system are higher than that of thelightning protection grounding system, Rnđ ≤ 4Ω complies with the current TCVN

4756 electrical safety grounding standards of Vietnam

- All protective wires of the electrical system are linked together andconnected to the safety grounding system including (wire "E" from sockets, metalcovers of electrical cabinets, electrical equipment ) The connection of the entiresystem by copper conductors or flat copper bars with cross-sections compatiblewith the cross-section of phase conductors

c Direct lightning protection system with active lightning rods

Early Streamer Emission device:

Products are designed and manufactured by reputable companies andaccording to EU standards This is an Early Streamer Emission device consisting

of 3 main parts:

* Lightning arrester

* Lightning conductor copper cable

* Lightning protection grounding system & electrical safety groundingsystem

* Specifications of active lightning rods

- Use direct lightning protection system installation

- Radius of protection: Rp = 51 Meters according to NFC Standard 17-102

- Technology: active lightning rods - Early Streamer Emission (ESE)

- Mounting column height: 5 meters

- Material: Stainless steel

- Connection: Coupling

- Use temperature: Ambient temperature

4.8 Leveling, drainage, gates, fences, yards, treatment plant roads, service roads:

a) Leveling the treatment plant:

The factory building land area (20x45)m is leveled with 03 elevations+66.50m; +65.50m; +64.50m in accordance with the current natural terrainelevation The ground leveling is compacted K=0.95

Main leveling work:

- Clear weeds, dig organically in the embankment

- Filling with organic materials, backfilling with ground leveling

- Dig the soil, fill the excess soil around, reinforce the base of the talus, andtransport it within the construction site

b) Drainage treatment plant:

To ensure drainage, prevent erosion and landslides in the treatment planarea, an M400 open ditch system is organized around the site, focusing on thecorridor around the sludge drying bed Surface water of the area is collected to thesump with reinforced concrete, 1x2 stone, M200 on a concrete foundation linedwith stone 2x4, M100 10cm thick Water from the sump drains out by the pipesection D315, the outlet is reinforced with masonry

Drainage volume

1 Drainage ditch M400 (soil

c) Gate, fence, internal road yard of treatment plant:

+ The fence is designed with barbed wire, 127m long, 1.6m high fence posts;

- Internal road yard:

+ Internal road: Used to travel within the treatment area more convenient andclean

+ Structure: Compacted ground level K=0.95; main road surface is 3.0mwide; 30.0m long; road mold is poured BT M200 stone 1x2 200mm thick

- Service road:

+ Building a public service road connecting the water treatment plant with theexisting concrete road in the cemetery with a length of 154.6m The existingroadbed structure is K95 compaction, the graded soil layer of the hill K98 is 30cmthick, the gravel layer is 5cm thick

+ Clearing grade 2 forests, building roads serving the construction of rawwater pumping stations connecting from service roads with an area of 328m2

4.9 Clean water supply pipeline:

a Network design solution:

The supply of water for daily life, production and services to areas under theproject scope requires quality assurance, durability and economy, and must complywith regulations of related industries: Construction, traffic… Clean water pipes arearranged along both sides of the main roads to ensure water supply for households

Therefore, the design of the pipeline network ensures the followingrequirements:

- The location of the pipe is located in the technical corridor of the road

- The height from the existing ground to the top of the pipe is calculated anddesigned according to the normative standards and is not too deep so that theconstruction investment cost is not high