Solid Waste Management and Recycling

THEO C. DAVIES, MOSES M. IKIARA, ANNE M. KARANJAAND

CHRISTINE FUREDY^1

CHAPTER 12

URBAN ORGANIC SOLID WASTE:PRACTICES IN NAIROBI

12.1. INTRODUCTION

Organic waste technically refers to waste containing carbon, including paper, plastics,

wood, food wastes and yard wastes. In practice, in municipal solid waste management

the term is often used in a more restricted sense to mean material that is more directly

derived from plant or animal sources, and which can generally be decomposed by

microorganisms. There are three main sources of organic wastes: (a) from rural gener-

ation; (b) from separate sources in urban areas, that is, source-separated organics (e.g.

green market wastes, canning industry wastes); and (c) from mixed municipal waste

(largely organic but significantly contaminated by post-consumer inorganics). Human

excreta are not included in urban organic solid waste for purposes of this study.

The organic portion of the municipal solid waste load generated in Nairobi constitutes

over 60 percent of the total (Karingi, 1997) and includes green waste, meat, bone and

fish remains from markets, hotels, schools, hospitals and other institutions, kitchen

wastes, farmyard manure, crop residues and yard trimmings, slaughterhouse remains

and a fraction that finds its way into dumpsites. An indeterminate proportion of these

wastes is separated and diverted to composting or fed to livestock, but the amount of

raw organic waste that is spread on farms is shown to be insignificant. Composting

and the use of raw materials like poultry waste and cow dung as manure as well as food

waste from hotels, markets and other institutions, as animal feed, continue to gain

importance as waste reuse activities that are helping to reduce the organic waste load

requiring disposal in Nairobi.

The biodegradable nature of these wastes, if combined with mixed municipal waste

that is improperly managed, poses health risks as they provide breeding grounds for

for disease-linked micro-organisms, insects and rodents. The stench emanating from

rotten organics in heaps of unmanaged solid wastes inconveniences many, while spon-

1. The authors acknowledge the help of the following research assistants for field surveys, under the
   supervision of Prof. Theo Davies and Dr. Erwin Koster: Kennedy Ogoro; Kevin Khisa; Harrison
   Kwach; Peter Omondi; Charles Wambugu; Alexander Mugo; Bernard Mwangi and Leah Oyake. Data
   analyses were carried out by Domisiano Mwabu, with Moses Ikiara, Theo Davis and Anne Karanja.

241

I. Baud et al. (eds.), Solid Waste Management and Recycling, 241-256.
© 2004 Kluwer Academic Publishers. Printed in the Netherlands.