Bulletin of the World Health Organization : 1979; Volume 57, Number 4, Year 1979 57 (4), Pages 513-533: Arthropod-Borne Encephalitides in the Americas

By T. P. Monath

Book Id: WPLBN0000069398
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Reproduction Date: 2005

Title:	Bulletin of the World Health Organization : 1979; Volume 57, Number 4, Year 1979 57 (4), Pages 513-533: Arthropod-Borne Encephalitides in the Americas
Author:	T. P. Monath
Volume:
Language:	English
Subject:	Health., Public health, Wellness programs
Collections:	Medical Library Collection, World Health Collection
Historic Publication Date:
Publisher:	World Health Organization


Citation APA MLA Chicago P. Monat, B. T. (n.d.). Bulletin of the World Health Organization : 1979; Volume 57, Number 4, Year 1979 57 (4), Pages 513-533. Retrieved from http://gutenberg.cc/

Description
Medical Reference Publication

Excerpt
1. Introduction Waste stabilization ponds are Large, shallow, usually rectangular basins in which there is a continuous inflow and outflow of wastewater. The biological treatment that occurs in ponds is an entirely natural process achieved principally by bacteria and microalgae, and one that is unaided by man who merely allocates sufficient space for them to occur in a controlled manner. 1.1 TyIEes of pond There are three principal types of waste stabilization pond comnionly used in Mediterranean Europe and elsewhere: anaerobic ponds, facultative ponds and maturation ponds. Anaerobic ponds, as their name implies, are devoid of dissolved oxygen and contain no (or very few) algae. Facultative and maturation ponds have large algal populations, which play an essential role in waste stabilization; they are thus sometimes called photosynthetic or natural ponds. There are some variations of these types: for example, facultative ponds may be divided into primary and secondary facultative ponds, which receive raw and settled sewage respectively (the latter commonly being the effluent from anaerobic ponds); and maturation ponds are sometimes used to improve the bacteriological quality of the final effluent from conventional sewage treatment works, and are then often referred to as polishing ponds. Maturation ponds are also occasionally planted with floating or rooted macrophytcs, when they are known as macrophyte ponds, but this is not generally recommended for the reasons given in Annex 1. In addition, there is a fourth type of pond, high-rate algal ponds, which are primarily for the production of algal protein (rather than wastewater treatment). This type of pond, which is still largely experimental, is not recommerlded for general use at the present time for the reasons given in Annex 2. The three main types of pond are usually arranged in a series comprising either a primary facultative pond followed by one or more maturation ponds, or an anaerobic pond followed by a secondary facultative pond and one or more maturation ponds (Fig. 1). Such series of ponds are very advantageous, as they enable the different types of pond to perform their different functions in wastewater treatment and so produce an effluent of the desired quality. Anaerobic ponds are most advantageously used for the treatment of strong wastewaters (BODS > 300 mgll) and those containing a high concentration of suspended solids. They, and facultative ponds, are designed primarily for the removal of organic compounds, usually expressed in terms of their biochemical oxygen demand (BOD), whereas maturation ponds are designed mainly for the removal of excreted pathogens (for which faecal coliform bacteria are commonly used as indicator organisms) and plant nutrients (principally nitrogen and phosphorus salts), although, of course, some removal of BOD occurs in maturation ponds and pathogens and plant nutrients are removed to some extent in anaerobic and facultative ponds.

Table of Contents
CONTENTS Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . ii 1 . Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . .1 1.1 Typesofpond . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Waste stabilization in ponds . . . . . . . . . . . . . . . . 1 1.3 Advantages and disadvantages . . . . . . . . . . . . . . . 8 2 . Current pond usage in Mediterranean Europe . . . . . . .9 3 . Process design guidelines . . . . . . . . . . . . . . . . . . . .10 3.1 Effluent standards . . . . . . . . . . . . . . . . . . . . . 10 3.2 Number of ponds . . . . . . . . . . . . . . . . . . . . . . 12 3.3 Design parameters . . . . . . . . . . . . . . . . . . . . . 12 3.4 Anaerobic ponds . . . . . . . . . . . . . . . . . . . . . . 13 3.5 Facultative ponds . . . . . . . . . . . . . . . . . . . . . 14 3.6 Maturation ponds . . . . . . . . . . . . . . . . . . . . . . 16 3 . 7 Small communities . . . . . . . . . . . . . . . . . . . . .19 4 . Physical design guidelines. . . . . . . . . . . . . . . . . . 20 Pond location . . . . . . .20 Geotechnical considerations Hydraulic balance . . . . . Preliminary treatment . . . Pond geometry . . . . . . . Inlet and outlet structures Security . . . Operator facilities . . . . 5 . Operation and maintenance . . . . . . . . . . . . . . . . . . . . 5.1 Start-up procedures . . . . . . . . . . . . . . . . . . . . 5 . 2 Routine maintenance . . . . . . . . . . . . . . . . . . . . 5.3 Operator requirements . . . . . . . . . . . . . . . . . . . 6 . Monitoring and evaluation . . . . . . . . . . . . . . . . . . . 6.1 Effluent quality monitoring . . . . . . . . . . . . . . . . 6.2 Evaluation of pond performance . . . . . . . . . . . . . . . 7 . Reuse of pond effluents . . . . . . . . . . . . . . . . . . . . . 7.1 Effluent storage reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References Annex 1 . Macrophyte ponds . . . . . . . . . . . . . . . . . . . . . . Annex 2 . High-rate algal ponds . . . . . . . . . . . . . . . . . . . Annex 3 . Design examples . . . . . . . . . . . . . . . . . . . . . .