T HE E C O L O GY OF W A S TE W A T ER T R E A T M E NT Η. A. H A W K ES Department of Biology College of Advanced Technology Birmingham PERGAMON PRESS OXFORD . LONDON - NEW YORK · PARIS 1963 P E R G A M ON PRESS L T D. Headington Hill Hall, Oxford 4 and 5 Fitzroy Square, London, W. i P E R G A M ON PRESS INC. 122 East 55th Street, New York 22, N.Y. G A U T H I E R - V I L L A RS ED. 5 5 Quai des Grands-Augustins, Paris, 6^ P E R G A M ON PRESS G.m.b.H. Kaiserstrasse 75, Frankfurt am Main Distributed in the Western Hemisphere by T HE M A C M I L L AN C O M P A NY · N EW Y O RK pursuant to a special arrangement with Pergamon Press Limited Copyright © 1963 PERGAMON PRESS LTD. Library of Congress Catalogue Card Number 62-16424 Made in Great Britain PREFACE THE treatment of waste waters, both domestic sewage and industrial effluents, usually depends, at some stage of the process, upon the activ­ ity of living organisms. Biological oxidation plants such as bacteria beds (unfortunately also termed "filters") and activated sludge plants are designed and operated by engineers and chemists who, in many cases, have little or no biological training. Such workers often find themselves in charge of the design, construction or operation of biolo­ gical oxidation plants and not fully equipped to create a suitable en­ vironment for, or control the activity of, the myriads of "workers" employed in the processes of purification. Furthermore, the invasion of the plant by trouble-causing organisms presents another biological problem. The aim of waste water treatment is the prevention of river pollution; in assessing the effect of a discharge on the receiving water, a knowledge of the biological as well as the chemical and physical effects is desirable. The treatment of waste waters in biological oxidation plants may be regarded as the environmental control of the activity of populations of the necessary organisms. Ecology, the theme of this book, is that branch of biological study which deals with the inter-relationships of populations and their environment. Any team working on waste water treatment problems, involving biological oxidation, should include a biologist. Even when this is the case the utmost co-operation is needed between the different professions involved, and without some under­ standing of the biology of the process, the non-biologist may have difficulty in appreciating the biologist's contribution. The aim of this book is to provide some understanding of the biological aspects of waste water treatment for the non-biologist employed in this field. The recommendation of a suitable introductory text book on biology for this purpose has been found difficult. Most "introductions to biology "would involve the reader in such studies as "the cranial nerves of the dogfish" or "the pollination mechanism of the sweet-pea" with viii PREFACE little or no reference to those groups of organisms he would find in his treatment plant nor to the biological principles involved. The many ramifications of ecology fringe on other branches of the biological sciences, such as taxonomy, physiology and biochemistry, and it is difficult to clearly limit the scope of the subject. The more advanced text books which deal with these subjects, some of which are referred to in the text, assume the reader has a basic biological training and furthermore because of the specialized nature of our subject it is neces­ sary to refer to several such books to cover the different aspects invol­ ved. In an attempt to meet this need the first chapter deals with those basic principles of biology considered necessary for an understanding of the following sections in which the dominant organisms present in different waste water treatment processes, are first enumerated and then the factors influencing their numbers and activity are considered, and finally the practical application of these factors to plant design and operation is discussed. Chapters 1 and 3 are based on a paper "Ecology of activated sludge and bacteria beds" which was presented by kind permission of Mr. M.R.Vincent Daviss, B. Sc., M.I.C.E., Engineer to the Birmingham Tame and Rea District Drainage Board, at the Second Symposium on the Treatment of Waste Waters, organized by Mr. P. C. G. Isaac, at the University of Durham, in September 1959, the proceedings of which were published as '''Waste Treat men f (Pergamon Press, Oxford 1960). Mr. Isaac suggested that the original paper could well be expanded to form a separate publication. The present book is the outcome of that suggestion which I gratefully acknowledge. The work is an attempt­ ed synthesis of the results of workers in many parts of the world. The synthesis of sometimes conflicting results and views has not been easy but it is hoped that a generally balanced view of our present state of knowledge has been presented. Again, the dangers of generalization and over-simplification of the theoretical aspects discussed in the dif­ ferent sections, is fully appreciated. However, it was considered that if each statement were qualified by a list of exceptions and if each topic were discussed in detail, the more important practical aspects would be obscured. Chapters 3, 6 and 7 contain the results of my own investigations on the ecology of bacteria beds. I wish to express my thanks to Dr. ECOLOGY OF WASTE WATER TREATMENT ix Ll. Lloyd, formerly of Leeds University, who first interested me in this subject and to him and to Dr. S. H. Jenkins, Board's Chemist, for their continued encouragement and interest in my work. To all who have assisted me and to many former colleagues on the Board's staff both in the laboratory, in the drawing offices and on the works who have influenced my thinking, I express my gratitude. Acknowledge­ ments are given individually in respect of the several diagrams which have been reproduced. I fully appreciate the inadequacy of discussing organisms the names of which do not create a visual impression in the mind of the reader. For this reason I have prepared the somewhat diagrammatic drawings representative of the range of organisms discussed, which do not form part of the common experience of the average person. Figures, 1.1-1.5 are intended for this purpose and not for use in identification, for which purpose much more detailed drawings are required. It is sincerely hoped that the following chapters will contribute to a fuller understanding by the non-biologist of the biological aspects of waste water treatment and thus enable a closer co-operation of engineer, chemist and biologist, in their joint task of creating more wholesome environments in our streams and rivers. Birmingham H. A. H. C H A P T ER 1 AN INTRODUCTION TO THE RELEVANT ASPECTS OF BIOLOGY OF the many branches of biology, we need concern ourselves chiefly with the naming and classification of organisms—Taxonomy, their activities or functioning—Physiology, and their inter-relationships with the environment—Ecology, T A X O N O MY To the non-biologist, the naming and classification of organisms is the most difficult aspect of biology and to many it is probably a deter­ rent to further study of the subject. A universal system of scientific nomenclature is essential for the interchange of information on organ­ isms and the specific identification of organisms is desirable. Never­ theless the identification of species in many groups is a task for the specialist on that group of organisms and is often outside the scope of the general biologist, let alone the chemist or engineer! With experience, however, it is possible to become acquainted with the more commonly occurring species in plants, the numbers of species being limited by the specialized nature of the habitat. The inability to name the species present in a plant should not, however, prevent one understanding the factors influencing their different activities in the process of treatment. It is usual to refer to organisms by two names, firstly the generic name denoting the genus and secondly the specific name by which it is distinguished from other species of the genus. In script it is conven­ tional to underline generic and specific names and in print they appear 1 2 ECOLOGY OF WASTE WATER TREATMENT in italics. Thus the common bacteria bed fly is Psychoda alternata and its less frequently occurring relative, Psychoda severini. In cases where specific identification is not possible it is usual to refer to the generic name only—Psjchoda sp. or Psjchoda spp. if referring to more than one species. Different species cannot interbreed to produce fertile offspring but may differ only in some small detail of structure. Such closely related species are grouped together into a genus, and similar genera into families and then through orders, classes, phyla into kingdoms, each grouping thus successively containing a greater diversity of organ­ isms. The classification of organisms is based on structure and is in no way ecological. Thus species of the same genus may occupy entirely different ecological niches, which they share with species from widely different genera. It would appear that in evolution the different species of a genus have radiated to fill different available niches. The riiany forms of Ufe inhabiting the earth today are considered to have been evolved from common stock and represent the more successful lines of evolution, many of the ancestral stock and less successful lines having died out. Although this selective elimination has left us with fairly well defined groups of organisms, making classification possible, the grouping is necessarily arbitrary and it is not surprising, therefore, that different classifications are found. Although not conventional, it is for our purpose convenient, to recognize three kingdoms of living organisms, plant, animal and a third kingdom which includes the fungi and bacteria. The major phyla in these kingdoms are given in Tab/e 1.1, the phyla of particular interest in our present study being indicated by capitals. Tab/e 1.2 shows the further division of these phyla with examples of the systematic position of some commonly occurring organisms. Structurally and functionally the basic unit of most organisms is the cell which is usually of microscopic size. This term was first applied to plant tissues where the cells are separated by a cellulose wall which is not found in animal tissues. Cells may be defined as unit masses of protoplasm contained within a limiting membrane and, in the case of plants, within a more rigid cell wall. Protoplasm may be regarded as a colloidal solution of proteins, lipoids and other substances which together possess the properties of life. The protoplasm of a cell is differentiated into cytoplasm, the outermost portion of which forms the limiting membrane—the cytoplasmic membrane, and a more RELEVANT ASPECTS OF BIOLOGY 3 TABLE 1.1. THE MAJOR PHYLA OF THE THREE KINGDOMS OF LIVING ORGANISMS [The phyla containing organisms of importance in waste water treatment are given in capitals] Kingdom Phylum PLANT THALLOPHYTA Primitive plants with little or no differentiation of thallus Bryophyta Mosses and Liverworts Pteridophyta Ferns and Horsetails Spermaphyta Seed-bearing plants FUNGI AND BA CTERIA FUNGI BACTERIA Viruses ANIMAL PROTOZOA — Non-cellular microscopic animals Porifera — Sponges Coelenterata — Simple animals having 2 layered body wall enclosing single body cavity e.g. Hydra, Jellyfishes PLATYHELMINTHES — Flatworms NEMATODA — Unsegmented roundworms ROTIFERA — Wheel animalcules Polyzoa — Moss animals ANNELIDA — True segmented worms ARTHROPODA — Animals with exo-skeleton and several many jointed limbs Mollusca — Snails, Limpets, Cockles and Mussels (Vertebrates) Chordata — Mostly possessing backbones ECOLOGY OF WASTE WATER TREATMENT TABLE 1.2. THE FURTHER DIVISION OF PHYLA INTO CLASSES ETC. SHOWING THE SYSTEMATIC POSITION OF SOME ORGANISMS OF IMPORTANCE IN WASTE WATE I TREATMENT Phylum SUB-PHYLUM CLASS SUB-CLASS Order THALLOPHYTA ALGAE CYANOPHYCEAE — Phormidium, Oscillator'ia (BLUE-GREEN ALGAE) BACILLARIACEAE — Single celled siliceous frustules, Cocconeis. (DIATOMS) CHLOROPHYCEAE — Contain the pigment chlorophyll. (GREEN ALGAE) Volvocales Unicellular or colonial. Chlamydomonas, Gonium. Chlorococcales — Unicellular or colonial, vegetative cells non-motile. Scemdesmus. Uloihrichales — Septate filaments, plates or tubes. Ulothrix, Enteromorphay Monostroma, Cladophorale s Filaments usually branched, cells multi­ nucleate Cladophora (Blanketweed) C hae tophorales Filaments with prostrate and projec­ ting systems. Stigeoclonium. Oedogoniale s Filamentous, ends of cells striated. Oedogonium. Conjugal e s Elaborate chloroplasts, no motile spores. Zygnemaceae — Filamentous. Spirogyra. Desmidiaceae — Mostly unicellular. Closterium. Siphonales — Filaments non-septate, Vaucheria. RHODOPHYCEAE — Elaboration of thallus. Batrachospermum. (RED ALGAE) BACTERIA BACTERIA — (Schizomycetes — fission-fungi) Euhacferiales: Mostly flagellate and unicellular. Spirillaceae: Markedly spiral; flagella polar. Spirillum. Pseudomonadaceae: Rod-shaped with long polar flagella. Nitrosomonas, Pseudomonas. Bacteriaceae: Non-sporing rod-shaped forms. Bacterium coliy Shigella, Salmonella. Chlamydobacteriaceae: Bacterium-like with mucous sheaths or stalks, and flagellated swarmers. Sphaerotilus, Bacillaceae : Rod-shaped with endospores. Bacillus Clostridium. Coccaceae : Radially symmetrical, usually non- motile. Staphylococcus. Actinomycetale s : Filaments with impermanent branches. Mycobacteriaceae: Short filaments. Mycobacterium. RELEVANT ASPECTS OF BIOLOGY 5 FUNGI PHYCOMYCETES — Non-septate filaments. Eeptomitus, Saprolegnia. FUNGI — Life cycle not fully known. Fusarium, Geotrichum. IMPERFECTI Sepedonium, PROTOZOA RHIZOPODA AMOEBINA — Move and ingest food by pseudopodia. ISuda — without shells. Amoeba. Τ es face a — with shells. Arcella, Difflugia. FLAGELLATA. (MASTIGOPHORA) — Move by whip-like flagella PHYTOMASTIGINA — Plant-like having pigments. Euglenoidina — spindle-shaped with 1 flagellum. Euglena. ZooMASTiGiNA —· Have no pigment and usually 2 or more flagella. Bodo. CiLioPHORA — Move by hair-like cilia. CiLiATA — Ciliated throughout life. Holofricha — Uniformly ciliated. Paramoecium. Heferofricha — Fine cilia with stouter cilia arranged in bands. Stentor. Hypofricha — Flattened ciliates having stiffer cilia ventfally as legs. Aspidisca, Sfy/onychia, Eup/ofcs. Perifrtcha — Bell-shaped bodies borne on stalks. VorticeUa, Opercularia, Carchesium, Episfylis. SucTORiA — Oniy ciliated in larval stage, have suctorial tentacles in adults. Acineta, Podophrya. PLATYHELMINTHES TuRBELLARiA — Free-living flat worms. Planaria, Dendrocoelum. TREMATODA — Parasitic, Flakes. Bi/harzia. CESTODA — Parasitic, Tapeworms. Taenia. NEMATODA — Free-living terrestrial or aquatic. Rhabdifis. Nemafoda. — Parasitic. Ascaris, Enferobius. ROTIFERA — Several orders, most important being Bdelloida — which are capable of swimming by ciliated discs and creep by looping movements as do leeches, forked tele­ scopic tail. Pbilodina, Kofifer. ANNELIDA OLIGOCHAETA — The earthworms and allies having chaetae or bristles. Τerricolae — mostly terrestrial. Lumbricidae — Large earthworms. Lumbricus, Eisenia.