OBTAINING BIOGAS AND COMPOST FROM ORGANIC WASTE WITH ANAEROBIC DIGESTION

OBTAINING BIOGAS AND COMPOST

FROM ORGANIC WASTE WITH

ANAEROBIC DIGESTIONÇAĞATAY KIRIŞ

WHAT IS ORGANIC WASTE

Organic waste is a type of waste which can be broken down, in a reasonable

amount of time, into its base compounds by micro-organisms and other living

things, regardless of what those compounds may be.

WHAT IS ORGANIC WASTE

http://www.greencoastrubbish.com/getting-serious-about-organic-waste-reduction/

Plastics, metals, rubbers, glass,

baby wipes, pet wastes can not

be treated as organic because

they can’t be broken down to

their base compounds by

microorganisms.

WHAT IS ANAEROBIC DIGESTION

Anaerobic digestion is a process where microorganisms break down organic

materials in the absence of oxygen. There, compost and biogas are produced.

Biogas includes 65-70% methane and 30-35% carbon dioxide. This biogas can

be used instead of the natural gas.

By producing renewable energy, anaerobic digestion offers the opportunity for

farmers, waste handling companies and industries with large volumes of

organic waste to cut their energy bills while, at the same time, reducing their

carbon footprint.

THE ADVANTAGES AND DISADVANTAGES

OF ANAEROBIC DIGESTION

ADVANTAGES

Less energy is needed

Production of methane is a source

of energy

Lower reactor volume would be

enough because of the high

concentration of the active

biomass

Reducing the overall emissions

DISADVANTAGES

Takes long time for digestion

Heating is a need for digestion

Aerobic treatment may be needed

in some cases additionally

There can be some issues like

lower output quality or odor

problem

High maintenance costs

Çalışkan, Y. (2013). Organik Madde İçeren Katı Atıkların Enerji Üretimi Amacıyla Anaerobik Kompostlaştırılması. Kocaeli: Gebze

Yüksek Teknolojİ Enstitüsü.

PROJECT AREA

Project will be made for an elderly house.

456 people live there.

The number of the employers is 100.

So, 556 people live there in total.

People in there, eat three times a day.

There is a kitchen and a restaurant for obtaining organic waste.

There is enough space for an anaerobic digester.

COLLECTING THE ORGANIC WASTE

Collecting the organic waste is the first step of this

project. The organic waste should be collected in

properly.

For this purpose, there will be new trash cans next to

the others for organic waste.

The organic waste will be collected every they to

prevent odor and bacteria.

Leaflets will be distributed.

https://www.co.ramsey.mn.us/NR/rdonlyres/C8066C32-2765-425D-9381-F639629BBB14/34408/organics_container.jpg

PARTS OF ANAEROBIC DIGESTER

Anaerobic digester consist of

A tank,

Termometer,

Gasometer,

Leachete collection tank,

Pump,

Liquid income - Gas output valves

Lines.



PARTS OF ANAEROBIC DIGESTER

Thermometer is used for measuring the temperature of the mixture.

Leachate collection tank is placed to collect the leachate and send it again to

the tank with the help of the pump.

The liquid income valve is used for controlling the incoming leachate.

The biogas, leaves the system under the control of the gas output valve.

Gasometer is used for measuring the amount of the biogas.



THE AMOUNT OF WASTE

According to Ministry of Environment and Urban Planning, in Turkey every

person produces 1.28 kg solid waste per day. 0.77 kg of it, is municipal waste

and 0.4352 kg of it, is organic waste.

Daily organic waste production:

0.4352(kg/per,day)x556(per)≅242(kg/day)

242(kg/day)/2=121(kg/day) for AD

Annual organic waste production

121(kg/day)x365(day/yr)= 44165 kg/yr

LOSSES OF THE ANAEROBIC DIGESTER

The losses of anaerobic digestion process can be listed as;

Sand – 7%

Inerts – 14.5%

Light Fraction – 17.5%

Evaporation – 9%

Other losses – 7%

These are variable values and can change with the components of the mixture

THE AMOUNT OF PRODUCTS

According to Istanbul Metropolitan Municipality Waste Management

Directorate;

Anaerobic digester can produce biogas as 12% of the organic waste and

compost as 33% of the organic waste.

If the calculations are made reffering to this literature;

44165 kg/year x 12% ≅ 5300 kg of biogas per year

44165 kg/year x 33% ≅ 14575 kg compost per year can be obtained.

http://www.ibb.gov.tr/sites/atikyonetimi/Documents/kompost.swf

EFFICIENCY

𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 =𝑃𝑟𝑜𝑑𝑢𝑐𝑡 𝑂𝑢𝑡𝑝𝑢𝑡

𝑀𝑎𝑡𝑒𝑟𝑖𝑎𝑙 𝐼𝑛𝑝𝑢𝑡

The weight of the obtained biogas is 5300 kg/yr

The weight of the obtained compost is 14575 kg/yr

Total material input is 44165 kg/yr

After the calculations we obtain;

𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 =5300+14575

44165𝑥100 = 45%

CAPACITY OF THE DIGESTER

For a plant which has a processing capacity of 5730 tons/yr, the installed

capacity is 430 𝑚3.*

If we take this example and use it in our project,

We assume the production value as 50 tons annually.

50𝑥430

5730= 3.75𝑚3

And we obtain a tank which has a diameter of 2.20 m and height of 1.00 m

𝑉 = 𝜋𝑟2ℎ = 𝜋𝑥1.12𝑥1.0 = 3.8𝑚3

*Bilgili, V., Yaldız, O., & Bilgili, A. (2011). Kompost ve Biyogaz Tesisi Fizibilite Raporu. Şanlıurfa: Harran University.

COST OF THE AD SYSTEM

Alternative 1

IECOG OK300NA

Compact system

No installation needed

Generating electricity 42 kWh/day

Fast composting

2mx1.2mx1.6m=3.84𝑚3

Total weight 1300 kg

Price = 7500 $

Higher maintenance cost

www.iecog.com


Alternative 2

2 Sets of PUXIN 2𝑚3 Portable AD

Easy to install

Biogas pump can be charged

with the solar charger of the

system

Generating electricty 3 kwh/day

per set

Total weight of 120 kg per set

Total price 2000 $ x 2 = 4000 $

Service life ≅ 10 years

www.puxintech.com


Alternative 3

PUXIN 4𝑚3 Under-Earth Type AD

Better efficiency

Better looking

Generating electricty 5kWh per day

Harder to install

Very long service life ≅ 30 years

Price 4000 $

www.puxintech.com


Biogas Appliances

Item Name Price (USD)

1 Room heater 12

2 Biogas stove douber burner 30

3Built-in Biogas stove douber

burner50

www.puxintech.com


Biogas Appliances

Item Name Price (USD)

4 Biogas lamp with fire maker 6.5

5 Biogas rice cooker 3L 35

6 Biogas water heater 60

www.puxintech.com

BARRIERS

High maintenance cost

Changing the gas lines with new ones

If aerobic treatment is needed, there will be a odor and bacteria problem.

Alternative 2 and 3 takes too much time for digestion.

It is hard to change the habits of the old people.

Alternative 1 has comsumes too much energy (37.5 kWh) than Alternative 2

(3kWh) and Alternative 3(5kwh).

You have to dig the Earth for repairing the alternative 3.

If the trash cans can not get cleaned everyday, there can be a health

problem.

Thank YouÇAĞATAY KIRIŞ