Excreta & Sewage Management/DisposalDR A ADENIRAN MBBS, MPH, FMCPH

CONSULTANT PUBLIC HEALTH PHYSICIANLAGOS STATE UNIVERSITY (COLLEGE OF MEDICINE)NIGERIA

Learning Objectives

Describe a sewage and other related terms

Describe diseases associated with in proper sewage diaposal

Describe the different methods of sewage disposal

Describe features of a sanitary sewage disposal

3Rural

15% without access to safe excreta disposal facility

75% use pit latrines60% discharge waste water directly to the

environmentPoor drainage aboundNo organised way of dealing with solid

waste by most residents

What is Sewage

Collective name for liguid or wet refuse consisting of excreta (faeces & urine), effluent from bath, kitchen, laundry, rain run off waste water

The pipes through which sewage flows are known as sewers and the network of pipes is known as sewerage

Excreta contains a variety of pathogens bacteria, viruses, protozoa, fungi and helminthes

Feacal Borne Diseases Examples Typhoid Para Typhoid Hepatitis A Dysenteries Diarhoeas Cholera poliomyelithis Helminthic & Parasitic Diseases: e.g

Ascariasis, Trichuriasis, etc

Sanitary Latrines Prevent the contact of faeces with 5 agents of

disease transmission- water, fingers, flies, soil and food

Features No faecal contamination of ground or surface

water No soil pollution No faecal contact with flies and rodents Free from odour and unsightly appearance

Method of Sewage Disposal1. Non water carriage systema. Pit latrine ( common in rural areas, little water, consist of the

pit, floor and superstructure, pit deep as 2.4m, floor should be slab, safe and strong

There are many modifications of pit latrine aimed at improving the sanitary features of this method of disposal. Eg VIP (Ventilated Improved Pit) latrine= minimize flies and odourb. Bucket latrine (water independent, bad method of sewage disposal, cheap to start but difficult to operate

2. Water Carriage Systema. Septic Tank & Soak away Pit (ST&SP) Method: Ideal

where there is water, consist of water closet, inspection chamber and the short pipe (sewer) which leads to the septic tank. The night soil discharges from the house through the sewer to the septic tank where it stays and anaerobic action takes place and from where a clear effluent leaves to the soak away pit and then absorbed by the surrounding soil. The sludge in the septic tank is removed when the tank is filled

b. Aqua Privy: Consist of water tight tank, faeces are stored in the tank which is kept at a constant water level. A soak away is also provided for the effluent from the aqua privy tank

Other Methods Chemical Toilet: consist of corrosive resistant container of

about 400 – 500 lit of bactericidal liquid e.g strong solution of sodium hydroxide or formaldehyde

Composting: Biological destruction process where excreta and refuse are mixed in a corrosive resistant container. The content is turned until decomposition is achieved. Humus is produced and CO2 and other gases are allowed to escape

Trench Latrine Consist of swallow trenches. Suitable for temporary sites such as camp, picnic etc, excavated soil from the trenches are left close to the latrine so that each user can use it to cover their feaces

questions