Biotreatment of industrial effluents CHAPTER 1 – introduction CHAPTER 2 – environmental disasters

Biotreatment of industrial effluents CHAPTER 1 – introduction CHAPTER 2 – environmental disasters Biotreatment of industrial effluents CHAPTER 1 – introduction CHAPTER 2 – environmental disasters Biotreatment of industrial effluents CHAPTER 1 – introduction CHAPTER 2 – environmental disasters Biotreatment of industrial effluents CHAPTER 1 – introduction CHAPTER 2 – environmental disasters Biotreatment of industrial effluents CHAPTER 1 – introduction CHAPTER 2 – environmental disasters

C H A P T E R 1

Introduction

Movement of Pollutants from the Source

A pollutant is defined as "a substance that occurs in the environment, at least in part as a result of h u m a n activities, and has a deleterious effect on the environment." The term pollutant is a broad term that refers to a wide range

of compounds, from a superabundance of nutrients giving rise to e n r i c h m e n t

of ecosystems to toxic compounds that may be carcinogenic, mutagenic, or teratogenic Pollutants can be divided into two major groups, namely, those that affect the physical environment and those that are directly toxic to organisms, including h u m a n beings The m o v e m e n t of pollutants and toxic compounds through the environment is called pollution (Fig 1-1) and is very similar to the m o v e m e n t of energy and nutrients w i t h i n the ecosystem or,

on a larger scale, through the biosphere

Rapid industrialization in the t w e n t i e t h century had led to the gener- ation of vast a m o u n t s of gas, liquid, and solid waste that were introduced into the environment w i t h o u t m u c h thought by the manufacturers of that waste This has affected the ecosystem and has caused health problems for the inhabitants residing near the factories As people became more aware

of the toxic effects of this waste, as they saw the destruction of the ecosys-

t e m due to the indiscriminate discharge of the pollutants, and as federal and local laws imposed more stringent discharge norms, efforts were made to treat these wastes so as to make t h e m innocuous before discharge into pub- lic systems Initially, the t r e a t m e n t procedures were based on physical and chemical methods, which proved to be inadequate and costly Biochemical methods, which have inherent advantages, are still in their early stages of development

Effluent Discharge Points to Keep in Mind

Several points related to the discharge of pollutants into public waterways

or land have to be kept in mind, such as: local laws on discharge limits,

2 Biotreatment of Industrial Effluents

FIGURE 1-1 Movement of pollutants VOC, volatile organic compound

the effect of the pollutants on the ecosystem (short- and long-term data may not be available), toxicity of the secondary metabolites, discharge

of secondary waste generated (such as sludge, inorganics, etc.), and the impact of modifying the existing microorganism population in the soil or water

Different Treatment Procedures and Factors

Affecting Technology Selection

The treatment of solid, liquid, and gaseous pollution can be carried out either

in situ (i.e., at the contaminated site) or ex situ (i.e., removing the polluted material, transporting it to another site or plant, treating it, and then bringing

it back to the site) Both approaches have several advantages and disadvan- tages The former is cost effective but could be slow and nonuniform The latter involves several steps and exposes the workers to the pollutants Physical, chemical, biological, and phytoremediation methods have been attempted to destroy pollutants The selection of the treatment technol- ogy (Fig 1-2) will depend on several factors, including cleanup time, maturity

of the technology, capital and operating costs, residual product toxicity after treatment, local discharge norms, reliability of the process, ease of facil- ity maintenance, company image, generation of volatile organic compounds (VOCs), and treatment of halogenated compounds or explosives

Introduction 3

Factors affecting process selection

method

-.,Jl Chemical

FIGURE 1-2 Selection of treatment technology

In situ physical and c h e m i c a l t r e a t m e n t t e c h n i q u e s include:

9 C h e m i c a l oxidation

9 Electrokinetic separation

9 P n e u m a t i c or explosive fracturing of the soil

9 Soil flushing using solvents, cosolvents, or surfactants

9 Vapor extraction

9 T h e r m a l t r e a t m e n t using electric resistance, injecting h o t air or steam, or

e l e c t r o m a g n e t i c h e a t i n g

9 C o n t a i n m e n t by creating physical barrier

~ Landfill

Ex situ physical and c h e m i c a l t r e a t m e n t t e c h n i q u e s include:

9 Extraction w i t h acid, alkali, solvent, or surfactants

9 M e c h a n i c a l separation such as magnetic, sieving, filtration, etc

9 Stripping using air or s t e a m

9 C h e m i c a l or t h e r m a l oxidation, reduction, or d e h a l o g e n a t i o n

9 Incineration

4 Biotreatment of Industrial Effluents

9 Absorption or adsorption of liquid or gaseous contaminants

9 Separation of liquid contaminants by distillation, ion exchange, crystal- lization, or membrane partition

An organic compound could be biodegraded by four different mechanisms, namely, (a) aerobic oxidation of an organic primary growth substrate (e.g., natural o~'ganic material, hydrocarbon fuels, chlorobenzenes, and the less oxidized chlorinated ethenes and ethanes); (b) anaerobic reduction, where the organic compound serves as the electron acceptor (e.g., highly oxidized chlorinated hydrocarbons, less chlorinated ethenes and ethanes such as trichloroethane); (c) coupled oxidation and reduction of an organic compound

by a fermentation pathway; and (d) cometabolism of an organic compound, which occurs when the degradation is catalyzed by an enzyme cofactor pro- duced by microorganisms for some other purpose The microbial processes involved in biodegradation are linked to the extraction of chemical energy for microbial growth, which comes from coupling the oxidation and the reduction reactions

Biological treatment technologies include:

9 Enhanced bioremediation (enhancement achieved by addition of nitrate, oxygen, or metabolites)

9 Bioventing

9 Bioaugmentation (organisms that have been specifically grown in the lab

on the contaminants)

9 Biopiles

9 Composting (windrow or static pile)

9 Land farming

9 Slurry phase bioreactors

9 Biosorption

Phytoremediation techniques include:

9 In situ phytoextraction/accumulation (removes toxins from the soil and concentrates them in the harvestable part of the plant)

9 In situ phytodegradation (plants and associated microbes degrade the pollutants)

9 In situ phytostabilization (the mobility of the pollutant is reduced through chemical modification or immobilization)

9 In situ phytovolatilization (volatilization of the pollutant into the atmo- sphere)

9 Enhanced rhizosphere biodegradation (plant roots absorb the pollutants) Cost of phytoremediation has been estimated to be $25 to $100 per ton of soil treatment and $0.60 to $6 per 1000 gallons for treatment of aqueous waste streams The cost of this remediation technique is estimated to be half that of any other treatment According to 1997 U.S Environmental

Introduction 5

Protection Agency estimates, the cost of using phytoremediation in the form

of an alternative cover (vegetative cap) ranges from $10,000 to $30,000 per acre, which is thought to be two- to fivefold less expensive than traditional capping (Macek et al., 2000)

Environmental Engineering An

Interdisciplinary Subject

Environmental engineering is an interdisciplinary subject encompassing microbiology, biotechnology, chemical engineering, chemistry, analytical chemistry, environmental chemistry, engineering design, and mechanical engineering Knowledge of atmospheric sciences, oceanography, geology, and civil engineering is also essential

Environmental engineering helps to maintain the quality of life through the betterment of the environment This means the development of suffi- cient clean water supplies; the prevention of air, soil, river, lake, ocean, and groundwater pollution; the maintenance of good air quality; and the reme- diation by natural means of land and water contaminated with hazardous chemicals The use of "natural means" is an important prerequisite, else we would be converting one type of pollution to another

Various Chapters in the Book and How They Are

Interrelated

The five most polluting industries in the United States (1987 data) are iron and steel, nonferrous metals, industrial chemicals, nonmetallic mineral products, and pulp and paper The polluting industries were classified on the basis of the comprehensive index of emissions per unit of output The index includes conventional air, water, and heavy metals pollutants (Mani and Wheeler, 1998) Table 1-1 compares the organic water pollution intensity

TABLE 1-1 Comparison of Organic Water Pollution Intensity

Index

Nonmetallic minerals 0.02

6 Biotreatment of Industrial Effluents

TABLE 1-2

Classification of Industries Based on Gaseous Pollution and Volatile Organic Compounds

High Iron Industrial Metals

chemicals Other chemicals Petrol refinery Petrol

Medium Industrial Iron Industrial

chemicals Metal chemicals

Other chemicals Paper and pulp Other chemicals

Petrol refinery Petrol refinery

Minerals Paper and pulp

Industrial chemicals Other chemicals Petrol refinery Petrol

Metals Paper and pulp

of various manufacturing sectors (Hettige et al., 1998) Table 1-2 groups the various manufacturing industries based on the intensity of gaseous pollution (Hettige et al., 1994; R6sner, 2003)

This book focuses on the biochemical treatment of gas, liquid, and solid effluents from a wide range of manufacturing industries such as dye, textile, paint, explosive, semiconductor, metal processing, pharmaceutical, organic chemical, petroleum, food and dairy, paper and pulp, pesticide, sugar and alcohol distillery, and polymer Also discussed is treatment of solid waste, including hospital and municipal waste; ground water decontami- nation, including fluoride removal; denitrification and biodesulfurization

of petroleum; and cyanide degradation Several biodegradation techniques described in the book are still in the research and laboratory stage; in such cases the physical and the chemical treatment techniques are being followed

by the relevant industries Although the industries chosen in the book appear

to be disjointed, they all are interconnected, as shown in Fig 1-3 For exam- ple, effluents produced by organic chemical, pharmaceutical, pesticide, and dye stuff industries all have several common characteristics Tannery, elec- trochemical, and semiconductor industries have metals in their effluents Dye chemicals are present in textile and tannery effluents Effluents from the food industry may have similar issues (Table 1-3 lists the effluent character- istics of various agriculture-based industries) The book also briefly compares the chemical and physical treatment procedures for these pollutants for the sake of completeness Both aerobic and anaerobic techniques and various types of reactors that have been used for treatment are also discussed in detail This book can be used as a ready reference for physical, chemical, and biochemical treatment of industrial pollutants as well as a source to understand the mechanism of biodegradation of a variety of contaminants

Introduction

8 Biotreatment of Industrial Effluents

TABLE 1-3

Comparison of Agricultural Industry Effluents

Effluent source COD (mg/L) BOD (mg/L)

Wool scouring effluent 45,000 17,500

COD, chemical oxygen demand; BOD, biological oxygen demand

Major Findings

A few broad conclusions can be listed based on the survey carried out by the authors:

9 The majority of the treatment procedures followed by industries is still based on physical and chemical methods

9 Biodegradation techniques are not yet broad based and have several unsolved problems

9 Most of the wastewater from the industries studied is very complex and cannot be treated by a single microorganism, so microbial colonies appear

to have good potential

9 Combined methods (physical, chemical, and biological or aerobic and anaerobic) show good potential

9 Biofilters are a cost-effective and ubiquitous reactor for treating VOCs and effluent gasses

9 Dynamic operation (as in sequential batch reactor) is able to achieve very high degradation rates compared with steady state operation

9 Membrane reactors have very good potential, but their cost factor makes

t h e m unpopular

9 White rot fungi (or any other extracellular organisms) are effective for general purpose degradation

9 Biosorption using dead surface-modified microorganisms is an effective technique for biodegradation and adsorption of metals from effluent streams

9 The majority of the biodegradation studies reported in the literature have been carried out with synthetic wastewater These findings and con- clusions have to be validated with real effluent, which may be more complex

I n t r o d u c t i o n 9

N e w Research Frontiers

A few of the areas that need focused study are:

9 Degradation pathways

9 Water-solvent interaction

9 Use of biosurfactants for enhanced degradation

9 D e v e l o p m e n t of microorganisms tolerant to toxic effluents

9 D e v e l o p m e n t of microorganisms tolerant to principal and secondary pollutants

9 Identification of bacterial consortiums

9 Transport of aromatic compounds through solid and liquid phases

9 Engineering of bacteria to do various ecological tasks

9 D e t e r m i n a t i o n of e n z y m e crystal structure

9 D e v e l o p m e n t of analytical tools

9 D e v e l o p m e n t of tools to follow the active organisms

9 Identification of n e w microorganisms from the e n v i r o n m e n t or from the

c o n t a m i n a t e d sites

9 Identification of novel supports

9 Long-term studies of the effects of pollutants on the ecology and the effects

of engineered organisms on the ecosphere

9 Wetland ecosystems

References

Hettige, H., P Martin, M Singh, and D Wheeler 1994 IPPS: The Industrial Pollution Projection System Policy Research Working Paper, p 1431

Hettige, H., M Mani, and D Wheeler 1998 Industrial Pollution in Economic Develop- ment: Kuznets Revisited World Bank Development Research Group Working Paper January

No 1876

Macek, T., M Mackova, and J Ka 2000 Exploitation of plants for the removal of organics in

environmental remediation Biotech Adv 18( 1 ):23-34

Mani, M and D Wheeler 1998 In Search of Pollution Havens? Dirty Industry in the World

Economy, 1960-95 J Environ Devel 15(9):4043

R6sner, A Pollution, Industrial Composition and Trade, Department of Economics Columbia University, USA, 2003 <http://www.columbia.edu/-~ar378/rosner_paper.pdf>

C H A P T E R 2

E n v i r o n m e n t a l .Dis asters

Environmental disasters occur because of natural or humanmade causes The latter could be due to the release of pollutants into the environment, either accidentally or because of negligence or insufficient knowledge about the material A flood that leads to human and material loss because of the building of a dam can also be considered a humanmade environmental dis- aster Sometimes it may be difficult to connect a disaster to the cause, but humankind has slowly started realizing that the subsystems in our ecosys- tem are intricately interconnected and every action can lead to a disaster at a later point in time Droughts, torrential floods, and other environmental dis- asters cost the world about $70 billion in 2002 (Reuters, 2002) In the United States, the number of incidents related to leakage or spills of chemicals and oil from pipelines, mobile units, storage tanks, railroads, and fixed manufac- turing units increased from 25,700 per year in 1991 to 32,200 per year in 2003 (National Response Center, U.S Coast Guard; http://www.nrc.uscg.mil/ nrchp.html) The present generation, which has benefited from past progress, has also inherited past environmental mistakes So it is the responsibility

of the current generation to ensure that future generations inherit only the benefits of the progress, that they do not inherit any past environmental mistakes, and that the mistakes of the past generations be corrected The United Nations Environment Programme (UNEP) and the U N Office for the Coordination of Humanitarian Affairs monitor environmen- tal occurrences (natural and humanmade) around the globe Several of their reports on humanmade disasters are listed in Table 2-1 Pollution abatement expenditures in the European community vary from 0.5 % of GDP in Greece and Spain to 1.6% of GDP in Germany The expenditure in the United Kingdom is about 1.2% of its GDP (1990 data, Ecotec Research and Con- sulting Co., 1993), whereas the cost of pollution control in Japan is on the order of 2% of its GDP

Various Disasters

This chapter briefly describes the various disasters that have occurred in the past few years and the problems caused by them The study of various

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