Reuse of Agricultural Wastes and Increase of Income of Farmers

By Yang Xiongnian

Department of Science and Education, MOA

Outline

1. Agricultural wastes and impact of the wastes on environment

2. Reuse of the wastes and increase of incomes and save expenses of farmers

3. Considerations for and focal points of work in the next stage

I. Agricultural Wastes and Impact of the Wastes on Environment

Agricultural Wastes

• Agricultural waste is a general

designation of wastes produced in

agricultural production, poultries and

livestock cultivation and agro-product

processing.

• Dejections of poultries and livestock

– Straws of crops

Dejections of Poultries and Livestock

• Dejections of poultries and livestock include

excrement and urine of poultries and livestock and

mixtures of the two and grass bedding.

• At present, China has 2.6 billion tons of total

amount of dejection of poultries and livestock

which is agricultural wastes of largest amount.

Environmental impact

• Water body pollution. High-concentration sewage

produced in livestock and poultries cultivation is

discharged into rivers and lakes which gives rise to

high eutrophication due to high nitrogen and

phosphor contents.

• Air pollution. Dejections of livestock and poultries

generate large amount of harmful foul gases by the

action of micro-organisms which have great impact

on air quality around the cultivation farm.

Straws of crops

• Straws of crops refer to inedible leaves and stalks left

over after harvesting crops such as paddy, wheat and

corn in the process of agricultural production.

• In 2009, China had about 687 million-ton straws of

crops.

Environmental Impact

• Health hazard: harmful substances such as sulfur

dioxide, silicon dioxide and inhalable particles are

emitted into the air in burning straws.

• Impact on traffic: The smog as a result of straw burning

gives rise to decrease in air visibility which has adverse

impact on road traffic and aviation safety.

II. Reuse Wastes and Increase Incomes and Save Expenses of the Farmers

Dejections of Livestock and Poultries

• Methane utilization

• Fertilizer utilization

Methane Utilization

Period Funds Invested

The Ninth Five-Year Plan

RMB 55.41 million yuan

The Tenth Five-Year Plan

RMB 3.534 billion yuan

The Eleventh Five-Year Plan

RMB 21.2 billion yuan

Historical Development of Household Methane

0

500

1000

1500

2000

2500

3000

3500

4000

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

2009

Increase Incomes and Save Expenses of the Farmers

• Methane as an energy resource:

Due to substitution of methane for firewood, coal and

liquefied petroleum gas, RMB 488 yuan of expense is

saved for a household, and a total amount of RMB

19.52 billion yuan of expense is saved in the event of

40 million biogas users.

Increase Incomes and Save Expenses of the Farmers

• Biogas as fertilizer:

Substitution of biogas tank slag for fertilizer and pesticide contributes to over 20% of decrease in fertilizer consumption. And RMB 520.2 yuan of expenses for a household and RMB 20.8 billion yuan of expenses for 40 million households will be saved as calculated based on total nitrogen, total phosphorus and total potassium contents in the biogas fertilizer.

Promote Industrial Development and Increase Incomes of the

Farmers

The “Four in One” Energy Ecological Mode in the North

The “ Pig-Biogas-Fruit ” Energy Ecological Mode in the South

The “Five in One” Energy Ecological Mode in the Northwest

The “Four in One” Energy Ecological Mode in the

North

• A farmer needs to build a sunlight greenhouse in the

courtyard, a underground biogas tank in one end of the

greenhouse, and a pigsty as well as a toilet on the biogas

tank. The farmer may plant vegetables or fruits in the

greenhouse.

• With biogas a link, crop farming and livestock breeding

are combined, beneficial ecologic cycle is established,

and incomes of the farmers are increased.

Plastic green

house

Carbon

dioxide

oxyge

n

Organic

fertilizer

biogas manure

s

The “Pig-Biogas-Fruit” Energy Ecological Mode in the South

• The farmers need to make use of nearby conditions such

as highland, water, and courtyard, build livestock and

poultry houses, biogas tanks, and orchards, and integrate

the construction of biogas tanks with that of livestock

and poultry houses and toilets, which will make up of a

courtyard economic system linking breeding, biogas, and

planting. This mode aims at establishing beneficial

ecological cycles and increase the peasants’ income.

Residues

biogas

Swine manure

digester

The “Five in One” Energy Ecological Mode in the Northwest

• Methane tank, toilet, solar energy warm sty, water cellar and garden irrigation facilities make up an integral system.

• With the methane tank as a link, fertilizers for

agricultural production and energy resource for domestic

use are combined, and a beneficial ecological cycle in

which livestock farming promotes methane generation,

methane promotes fruit output and fruit promotes

livestock farming is established which contributes to

increase of incomes of the farmers.

Schematic Diagram of the “Five in One” Energy Ecological Mode in

the Northwest

Fertilizer Utilization

• In 2008, there are 3,021 organic

fertilizers plants with total production

capacity of 24.88 million tons in China.

Straws of crops

• Straws of crops

• Fertilizer

• Feedstuff

• Base material

• Industrial raw material

• Fuel

Proportion of Use for the Purposes

燃料

18.7%

饲料 30.7%

肥料 14.8%

基料 2.1%

工业原料 2.4%

未利用 31.3%

Not utilized Fuel

Industrial raw material

Feedstuff Base

Fertilizer

Comprehensive Utilization of Straws-for Fertilizer

Straws have contents of high organic substances, nitrogen, phosphor and

potassium and microelements. There are over 3 million tons of nitrogen, over 7

million tons of phosphor and over 7 million tons of potassium in the 678 million

tons of straws in a year, which are equivalent to 1/4 of fertilizer consumption in

the country and are importance sources of organic fertilizers for agricultural

production.

25

秸秆粉碎覆盖还田 铧式犁翻埋还田

Benefits Analysis

• In 2009, straws from 358 million mu

farmland were returned to the

farmland after treatment by machines,

and about 102 million tons of straws

were utilized.

Comprehensive Utilization of Straws-for Livestock Raising

4-ton straw have nutritive value equivalent to nutritive value of 1-ton cereal.

27

Straw Silage Technology

Benefits Analysis

• Livestock raising using straws promotes

development of herbivore breeding and

contributes to reduction of foodstuff

consumption and cost of livestock raising.

• In 2009, our country had 211 million tons of

feedstuff made of straws.

Comprehensive Utilization of Straws-for Base for Edible Fungus

There are rich nutrients such as carbon, nitrogen and

minerals in straws which are suitable for materials for

cultivating edible fungus.

29

Benefits Analysis

• Utilization of straws for culture mediums for

edible fungus makes contribution to reduction

of wood use and production period and

allows higher conversion efficiency.

• We have about 18 million tons of total output

of edible fungus and utilize about 15 million

tons of straws.

Comprehensive Utilization of Straws-for Industrial Raw Material

Straw fiber as a natural

cellulose can be for raw

materials for paper pulp, heat

insulating material, packing

material, light-weight sheets

and basketry.

About 16 million tons of

straws are used as industrial

material.

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Comprehensive Utilization of Straws-for Fuel

Straw methane

Straw solidifying

Decomposition gasification of straws

32

Technology of Methane Generation with Straw

• To 2009, there were 159 projects for

centralized supply of methane gas

generated from straws in the rural

areas of our country.

System of Centralized Supply of

Methane Gas from Straws (Decheng District in Shandong)

Straw Solidifying

• Lignin is used as an adhesive for extruding agricultural

wastes such as loose straws into blocks or particles to

improve energy source intensity and combustion

characteristics.

• To the end of 2009, there were 259 solidifying treatment

places with annual output of molded fuel of 720,000

tons.

Different Molded Fuels Made of Straw by Means of Solidification

Technology of Straws Thermal Decomposition Gasification

• Centralized methane supply system using straw

gasification technology is a new technology for

utilizing biomass energy development in China since

the 1990s.

• To the end of 2009, there were 888 stations for

thermal decomposition and gasification of straws in

our country.

Centralized Supply of Methane Generated by Means of Thermal

Decomposition and Gasification of Straw

Benefits Analysis

• Income increase and expenditures saving

– About RMB 900 yuan of expense will be

saved for a household when energy

generated from straws is used to substitute

for coal.

III. Considerations for and Focal Points of Work in Next Stage

Guide on Development

• Adhering to the scientific outlook on development and

the general tenors of the Third Plenum (Plenary Session)

of the Seventeenth Communist Party of China Central

Committee, sticking to the idea of cyclic economy

characterized by “less waste, waste reuse and re-use”,

aiming at building a new-type resource-saving and

environment-friendly rural area, all efforts are made in

methane gas and comprehensive utilization of straws in

rural area to promote reuse of wastes such as dejections

of livestock and poultries as well as straws to turn wastes

into things of value, convert harm into benefit, and

increase incomes of the farmers.

Technical Innovations

• Methane canning ：

• Cellulosic ethanol

• ……

Increase Investment

• The planning for comprehensive

utilization of methane and straws in

rural area affiliated to the Twelfth

Five-Year Plan is to be worked out,

and investment is to be increased.

Thanks!