DECENTRALIZED APPROACHES TO
RURAL WASTEWATER TREATMENT
IN CHINA:
CHINA SITUATION AND
CHALLENGE

Dr. Meixue Cheng Guo
Dr. Xuesong
North Center for Rural Wastewater Treatment Technology Research
Ministry of Housing and Urban-Rural Development, China
Nov. 20,2013

Domestic wastewater treatment coverage in
population by on
on--site and off
off--site systems

Domestic wastewater treatment rate
in urban from 1991 to 2011
90Do
omestic wastewateer treatment rate inn urban %80
city70County60

504030201001991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011YearsXinjiang
X

Ningxia

Qinghai
QGansuShanxiXizangYunnanGuizhouG

SSichuanChoongqing

HainanGuangxi
GGuangdong

Hunan

Hubei

Henan

Shandong

Jiangxi

FujianAnhui

ZZhejiang

JiangsuShhanghai

Heilo
ongjiang

Jilin

LLiaoningNeimmengguShanxi

Hebei

TianjinBeijing

Treatment rate %Domestic wastewater treatment rate
in urban in 2011 year
1009080706050County40City3020100

Domestic wastewater treatment rate
in 2011year
100908070town
townshipTreatment rate %village
6050403020100

Water Pollution Situations
Good water ratio：percentage of sections meet Class I-III standards

80
80

100
100

水质良好率
水质良好率

污水处理率
污水处理率

8080

污水处理
污
理率，%
Sewagetreatmeent ratio,%,%%
污水处理
污
理率，%

Goo
od良好率
waterratio, %率，%良好率率，%

100
100

60
60

60
60

40
40

40
40

20
20

20
2000
1998
1998

00
2002
2002

2006
2006

2010
2010

2014
2014

Construction of MWTPs contributes to the improvement ofwater quality. But it is not enough.

Pollution loads

town

village

T&V

city

SV(108m3/a)

3.6

5.6

9.2

33.0

COD(106t/a)

2.6

5.4

8.0

8.6

N(106t/a)

0.5

1.1

1.6

0.97

P(106t/a)

0.04

0.07

0.11

SV: sewage volume

Support systems at national/local level bygovernment for promotion of onon--site domestic
wastewater treatment

Guides

东北
华北
西北华南
西南中南

不同区域农村生活污水处理技术指南
不同区域农村生活污水处理技术指南Technical code and specification

Introduction of several popular on
on--sitetreatment technologies in China

Rural wastewater(7% spray drain, and wastewater treatment)

Decentralized technologies
 Reduce the effect on theenvironment and public health Increase the ultimate reuse ofwastewater Overcome the problem associatewith site conditions and flexible inmanagement
Cost

Needs for decentralized wastewater systems

1. Satisfy the demand of public healthand various water quality goals;
2. Economic suitability of processing
technologies;
3 Operation simple and easy routine
3.
management..
management

Types of decentralized wastewater systems• Primary treatment– Septic tank

• SecondarySdttreatment---treatment
tt----Biological
Bi l i l technologies
Biologicalt h l i– Biofilm– Anaerobic digesters• EcoEco--technologies– Constructed wetlands– Leach trenches• Community Systems

Case study: Septic tankeffluent
Influent•Inexpensive
Inexpensive•Simple to maintainthe firsttank

the secondtankthe thirdtank• Sludge
Sl d may cause an odord problembl• Not effective in removing nitrate andphosphorus and pathogenic organics• Potential pollution source ofgroundwater

Case study: Anaerobic Treatment

Water
recycling tankFertilizer tank

Anaerobictank• Low cost
• Energy use• Low removal rate
• Maintenance is necessary

Case study: Activated sludge

1m³,2m³,5m³,10m³,15m³/day• Flexible for decentralize wastewater treatment• Automatic control• Expensive for single family• management is relative complex

Case study: Constructed wetland
Plant

Water distribution

Effluent
Waterbody

GrassWetland
Water‐proof
Waterproof• constructed cost
• flexible land use
Small-scale decentralized
Smallsystem• LowL
removall rate

0.2--5m3/d0.2• Management

Case study: Leach Trenches
AA’

Ф75mm

Ф110mm覆盖层覆层细滤层碎石(Ф10‐30))
碎石(砾石(Ф5-10)
砾石(5 0)精虑层

PVC 管粗虑层• Constucted and operation simple• Low cost
• pollution of groundwater• Poor quality of effluent

Case study: anaerobic tank+ ladder ecoeco-filter
7
HRT:10--20min
HRT:106518

HRT:10--20min
HRT:10293

10

HRT:20--30 min
HRT:20

4
11
HRT:30--60min
HRT:301215 m3•d-1• Energy save

Unit：mg/L
item

COD

Influent

400

Effluent

60

BOD5NH4+-NN

TNTP

SS

150

2540

4200

20820

120

• Amonium and phosprous
removal• OdorCase study: Anearobic+ drop aeration + constructedwetland

高位
水箱

DN40

跌水挡
板

DN100

排管道外

DN200
DN40潜污泵厌氧池 tank
Anaerobic

DN100

回流

触氧
化池Oxic接人
工湿地 wetland
Constructed

Case study: BioBio- rotation + vegetable tank
3～10t/d
10t/d，，COD concentration is 100～100～100mg/L• Suitable in south area
• Vegetable management complex

Case study: Cluster system

W t
Wasterwater

Discharge

ScreenBiofilter• Cluster system• Highg qualityqy of effluent

Constructed wetland••

60m3/d/d，，for 900 persons
floor area: 250m2

Decentralized wastewater systems
For COD removal

Aeration process
For nitrogen removal

Bio+Eco TreatmentChallenges in promoting onon-sitewastewater treatment

Situation•••

Lack of knowledge of decentralized systems
Lack of longlong-term operation data
Management needed– systems are a costcost-effective and longlong--term option
for meeting public health and water quality goals– Who is responsible? Typically homeowner for
onsite，onsite，Inadequate methods of needs assessment

Developing for decentralized system in China

Appropriate technology

Economic
Aff d bl
Affordable•Investment•Population density•Technology efficiency•Operation and maintenance•Residuals management

EnvironmentallyS
Sustainablei bl

Social Acceptable•Environmental protection•Public health protection•Resources conservation•Government policy and regulation•Water reuse•Human settlement•Nutrient recycling•Planning

May A. Massoud,2009

Developing for decentralized system in China•Policy
P li•Specifications
S ifi ti
•R&D of technologies•LongLong--term evaluation•Operator training

Thanks for your attention!