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 5

TOPIC: SANITAION

CONTENT 

• Sanitation  
• Non-Network  Disposal System 
• Other Non-Network 
• Aqua Privy 

Introduction 

Sanitation can be defined as the equipment and system that keeps places clean, especially by removing human wastes.

The success of any sanitation programme does not depend on the provision of sanitary facilities rather upon collective responsibility through individual discipline for the good of all. Therefore, the importance of good sanitation to the health and general well-being of people cannot be over-emphasized 

Poor Sanitation has been linked to the spread of diseases such as cholera, diarrhea, and typhoid e.t.c. Pathogens are disease-producing organisms e.g. mosquito, housefly and tsetse fly. 

The design of a sanitary system should have the following factors in focus:

Health factors 

1. Fresh excreta should not be handle nor exposed to flies 
2. Soil surface and ground water should not be contaminated 

Cost factors

1. The construction cost should not be exorbitant 
2. Local materials and expertise should be employed for the purpose of construction and maintenance.

The basic objectives of any sanitary system are to reduce the BOD (Biochemical Oxygen Demand) and achieve the reduction and control of pathogens. Biochemical Oxygen Demand is a measure of organic pollution. It is usually expressed milligrams/litres of solution  

Non-Network Disposal System 

The common latrines, the aqua privy system, the septic tank system are referred to as the non-network systems.

The different types of latrine are the bucket latrine, pit latrine and incineration latrine.

Bucket latrine 

The success of the bucket latrine depends critically on organization.

The bucket latrine is an example of what is called a removal method. It involves storing human waste in containers from where night-soil men evacuate them. The bucket consists of four main elements, namely:

1. The defecation area- The latrine and the container to hold the excreta.
2. The removal of excreta to some other container or the replacement of a full container by an empty one 
3. Transportation system for moving excreta to some depot.
4. Treatment processes, disposal and/or utilization.

The evacuated waste can be disposal of in any of the following ways:

• Burying underground 
• Depositing into water
• Burning 
• Composting with refuse
• Sending to digester for biogas production 

Problem with bucket latrine is the need for the night-soil men to regularly and carefully remove the buckets to ensure that there is no spillage, which leaves the area very unsightly and full of odour.

Pit latrine 

The pit latrine consists of the pit, the floor slab or the squatting plate and the superstructure. It is recommended that the floor slab be constructed with concrete reinforced with steel bars. The pit latrines can be made more popular by providing vents as well as water seals.

In the construction of pit latrine the following factors should be considered at the design stage:

1. Cost 
2. Reliability and comfort 
3. Fly control  
4. Superstructure which must be supported properly so that it is not blown away in any storm.

A pit latrine should be deep as possible to ensure long life. It will dark and thereby prevent breeding of flies and also reduce odour. It is supported particularly in areas where the soil is weak or where the ground water is likely to rise above the bottom of the pit latrine.  In such cases, pit latrines should be lined.1:3:6 concrete mix is recommended for the base. The concrete floor should reinforced and inter locked in between. It should also be vented, as vented latrines have been shown to be odourless and to have less number of flies, due to air circulation.

Aqua Privy 

The aqua privy is a device whereby faeces are stored in a water-tight pit, floor slab, and soak away pit. It is not as expensive as the septic tank, while having many advantages over the ordinary pit latrine.

In aqua privy, excreta are deposited directly into a tank rather being flushed along a pipe network as in the case of a septic tank system. For septic tank system, digestion of excreta by anaerobic bacteria takes place in the tank. Faeces enter the tank from the above the squatting plate through a vertical drop pipe, with an optimum  diameter of 15cm, whose tip should be at least 10cm deep in the water. 

Advantages over pit latrine

1. The water seal makes aqua privy to eliminate odour 
2. The water seal makes aqua privy  to eliminate flies
3. It takes longer period to fill  ( since the bacteria digest the faeces more efficiently in the water medium)
4. It requires a small amount of water for daily maintenance 

Advantages over septic tank

1. It is easier to construct 
2. it is less expensive 
3. It requires less operation 

Cautions 

The water level in the tank must be maintained by topping it up daily with about 14 litres of water. This quantity of water can be used initially to wash the floor and wall of the inlet drop pipe into the tank every morning.

Other Non-Network 

1. Chemical Toilet: A chemical toilet as the name implies consists of a container, which holds a strong solution of bactericidal liquid (liquid capable of killing bacteria) such as sodium hydroxide and formaldehyde. The chemical toilet is ideal for people I boats, buses and trains.
2. Incineration Latrine:  In incineration latrine, excreta are deposited in latrine equipped with an incineration for immediate combustion. The ashes have to be removed. One of the drawbacks of this method is the need to provide fuel energy.
3. The Composting: In this method, excreta, garbage, and paper are put into a container, which is resistant to corrosion. Air is admitted and provision is made for gases to escape. The contents of the container are turned regularly, as they are subjected to biological destruction. Humus is product; water vapour, carbon dioxide and other gases are allowed to escape. 

Reading Assignment 

Read “SANITATION”

Reference Materials:

• EVANS, INTRODUCTORY TECHNOLOGY FOR JSS, BOOK 3, pages 206-214

Weekend Assignment 

1. _________can be defined as the equipment and system that keeps places clean, especially by removing human wastes.(a) Sanitation (b) latrine (c) aqua privy (d) soak away
2. The common examples of latrines include the following except (a) pit (b) bucket (c) incineration (d)  sewage 
3. Latrines, the aqua privy system, the septic tank system are referred to as the ______ (a) non-network systems. (b) network systems (c) revolutionary system (d) non-revolutionary systems
4. A device whereby faeces are stored in water-tight tank with constant water level is called __ (a) Sanitation (b) latrine (c) aqua privy (d) soak away
5. The objective of any sanitary system are as follows except (a) to reduce the BOD (b) to reduce the activities of pathogens (c) to control micro-organism (d) to increase government revenue 

Theory 

1. Define sanitation. State 3 types of latrines
2. Draw and explain the operation of Aqua privy toilet.