Design a surface flow CWs to treat domestic wastewater for an residential area

Our topic: • Design a surface flow CWs to treat domestic wastewater of a residential area of 1000 people Assume that 1 person consume 150 lit water/day and wastewater amount is 80% of wa

Group 11

Đặng Minh Sơn Nguyễn Quang Văn Nguyễn Thanh Tùng

Vũ Thị Thu Trang

Our topic:

• Design a surface flow CWs to treat domestic

wastewater of a residential area of 1000 people

(Assume that 1 person consume 150 lit water/day and wastewater amount is 80% of water supply)

 We choose to use horizontal surface flow CW for this design

I Introduction

Wastewater treatment by wetland

• First made by Seidel (1955) at the

Max Planck Institute in Plon,

Germany

• Applied and developed countries

in Europe, America, Australia

in the years from 1970 to 2000

• Vietnam : that method was done

at universities, research institutes

in recent years and got some

initial encouraging result

 Most domestic wastewater in the residential urban, suburban and rural Vietnam are not handled properly.

 Wastewater from toilets only preliminary treatment, unsatisfactory discharge into the evironment has been mixed with waste water from the kitchen, bathroom, laundry cause pollution, the spread of diseases

Free water surface (FWS)

• These systems typically consist of basins or

channels, with some sort of subsurface barrier

toprevent seepage, soil or another suitable medium

to support the emergent vegetation, and water at a relatively shallow depth flowing through the unit

The shallow water depth, low flow velocity, and

presence of the plant stalks and litter regulate water flow and, especially in long, narrow channels

minimize short circuiting.

1 Domestic wastewater compositions

2 CWs calculation

3 Vegetation and Soil

II Designing

Domestic wastewater contains BOD, SS, NH4+, Nitrogen, Phosphorus, Microorganisms….

Compositions Unit Amount

Table1: Typically polluted concentration and compositions

1 Domestic wastewater compositions

• Wastewater treating is in order to remove

contaminants before discharging to the culverts

or recycling

• Water quality after treatment must satisfy the

National technical regulation on domestic

wastewater – QCVN 14:2008/BTNMT

Compositions Unit Amount

(influence) Co

Amount (effluence) Ce

Parameter Unit Concentration C

3 Total suspended solid (TSS) mg/l 50 100

4 Total dissolved solid (TDS) mg/l 500 1000

A: for domestic supply purpose

B: not for domestic supply purpose

• Problem requirement: Design a surface flow CWs to treat domestic wastewater of a

residential area of 1000 people (Assume

that 1 person consume 150 lit water/day

and wastewater amount is 80% of water

supply)

2 CWs calculation

dn s A v

A T

K

Ae Co

Ce

75 1 ) (

7 0

Av = specific surface area for microbial activity, m 2 /m 3

As = wetland treatment area, m2

d = design depth of system, m

n = porosity of system (as a decimal fraction)

Q = average hydraulic loading on the system, m 3 /day

K T = temperature-dependent rate constant KT (in day-1) at water temperature T ( o C)

BOD5 Removal in FWS Wetlands

dn s A v

A T K

Ae Co

Ce

75 1 ) ( 7 0





 A sample calculation for the

above coefficients equation

yields the following results:

 Q = average hydraulic loading

on the system, m 3 /day:

Q = 1,000people x 150L/person/ day x 80% =120,000L/day

=120m 3 /day

 As ranges from 320.67 m 2 to 478.36m 2

120

75.06.07

.1510

2.97

52

Assume, length : width = 3 : 1

 The length is about 32m ~ 38m

 The width is about 10m ~ 13m

• Soil Permeability for Free Water

Surface Systems

• The most desirable soil

permeability is 10 -6 to 10 -7 m/s

(0.14-0.014 in/hr) Sandy clays

and silty clay loams can be

suitable when compacted

• Canna Hybrid: Strong growth

III Result

-Organic loading: < 112kg BOD5-Hydraulic loading: 0.7-5.0 cm/day -Detention time: 5-15 days

20-30 cm

For 1000 people:

• In terms of social topics will contribute to improving

the health of communities through clean water and create a good view from the technology underground leach plant

• In terms of biodiversity conservation: Thread has

created a good view and contribute to increase

biodiversity in areas with abundant types of crops in the leach

Conclusion

• In terms of economic and biodiversity: This type of

model wastewater by biological treatment principle does not need to use energy saving will be very

effective and economical when applied in practice

than other methods In addition, the leach plant can

be used as feed for livestock Treated water can

circulate to bathe using pigs, barn wash or irrigate

crops are good

THANK YOU FOR LISTENING

Nguyenloankhoamoitruong@gmail.com