Lesson Notes By Weeks and Term - Junior Secondary School 3

SUBJECT: BASIC TECHNOLOGY   

CLASS:  JSS3

DATE:

TERM: 3RD TERM

Reference Materials:

1. EVANS, Introductory Technology For JSS, Book 3.
2. NERDC, Introductory Technology For JSS, Book 3.

Week 2

TOPIC: ENERGY SOURCES- BIOGAS PRODUCTION           

CONTENT:

• Introduction to biogas technology   
• Biogas 
• The production of biogas from waste       
• Biogas plant           

Introduction 

Cooking gas used as domestic fuel is a liquidified-petroleum gas (LPG) from oil refineries. This is main source of our cooking gas. However, it is possible to get cooking gas from other sources. One of such sources is biogas.

BIOGAS 

Biogas is produced from the fermentation of animal wastes by bacteria in an oxygen-free atmosphere. The wastes, which can be used to produce biogas, are human excretion, dungs (from cow, goat, sheep and pigs), poultry dropping, urban refuse, and agricultural wastes. The process of releasing gas fuel by bacterial digestion of wastes is scientifically referred to as biosynthesis. Hence, the gas released from the process is called biogas.  

Evaluation 

1. State main source cooking gas.
2. Briefly explain biogas 

The Production of Biogas from Wastes.

Biogas plant consists of two parts namely: 

1. The digester and 
2. The floating gas storage tank.

The digester contains the wastes to be digested. The waste is mixed properly into slurry, and then fed into the digester through the waste inlet. The waste is then left in the digester to ferment from a period ranging from 7-14 days. As a result of fermentation, biogas is released, and collected in the floating storage tank which floats in the digester.

As fermentation progresses, more gas is released and collected in the floating storage tank. The gas rises up in the digester as the gas pressure increases. The biogas flows out under its own pressure through the gas outlet. If such a digester is situated at the back of a kitchen, biogas is connected directly to the gas stove to be used as cooking gas.

Evaluation 

1. Explain the importance of bacteria in the biogas production
2. Briefly discuss activities in the following during biogas production (i)  the digester (ii) the floating gas storage tank.

Reading Assignment 

Read “RENEWABLE ENERGY –BIOGAS”

Reference Materials:

• EVANS, INTRODUCTORY TECHNOLOGY FOR JSS, BOOK 3, pages 190-191

Weekend Assignment 

1. Cooking gas used as domestic fuel is a (a) hydrogen gas (b) carbon dioxide gas (c) liquidified-petroleum gas (d) neon gas
2. Another source of cooking gas is ____ (a) biogas (b) chemgas (c) physogas (d) mathgas
3. Which of the following is not a waste used for biogas production (a) dung from cow (b) poultry dropping (c) urban refuse (d) oil spillage
4.  Biogas plant consists of two parts namely (a) the digester and the floating gas storage tank. (b) mixer (c) gas jar (d) porous pot
5. The waste is then left in the digester to ferment from a period ranging from (a) 7-14 days (b) 28- 35 days (c)14-21 days (d) 21-28 days

Theory 

1. Define biogas
2. Explain the operation of biogas plant