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reduction in bulk is more important than residual weight when the effect of incineration on the life of a sanitary landfill site is assessed. Tins and bottles, which come through the incineration process largely unchanged, make up a large proportion of the combustible weight and bulk of domestic refuse. If these items were segregated by the householder they could be hauled directly to a landfill site and thereby effect a considerable saving in incineration cost and the cost of residue hauling. However, the housewife finds the practice of segregating solid wastes into separate refuse containers (for example, garbage, combustible refuse and incombustible refuse) onerous and objects very vigorously to such a system. Therefore, the usual practice is to collect mixed refuse and haul the small incombustible items to the dump after they have passed through the incinerator.
Incineration, including burial of the residues, is a relatively expensive disposal method and costs about $5 per ton, as compared to $1 or $2 per ton for sanitary landfilling without incineration when conveniently located large tracts of cheap waste land are available for this purpose. When remote landfill sites must be utilized, transportation costs become an important fraction of the total disposal cost, and transfer of loads from 5-ton or 8-ton packer pickup trucks to 20-ton trailer trucks at intown locations becomes an economical procedure. The experience of Los Angeles shows that transfer operations increase handling costs by $1.25 per ton of refuse. Haulage costs are $12 per hour for an 8-ton truck ($1.50 per ton per hour) and $15 per hour for a 20ton trailer load ($0.75 per ton per hour).* Operating time has been found to be a more reliable guide to costs than the mileage covered, for per mile costs fluctuate widely, depending on local terrain and traffic conditions.
The small percentage of combustion products emitted to the atmosphere from waste incineration that is not carbon dioxide or water vapor consists of ' particulate matter (soot, smoke and gas-entrained solid residues), organic gases (hydrocarbons or aldehydes) and inorganic gases (sulfur dioxide, hydrogen chloride or oxides of nitrogen). These are all recognized as air pollutants. Under ideal operating conditions, a modern high-temperature municipalwaste incinerator totally destroys all organic matter, and the emissions that are of special interest because of their effect on the air environment will be inorganic - principally, particles of solid residue, oxides of sulfur and nitrogen and hydrogen chloride.
All particulate emissions, including smoke, can be eliminated or greatly reduced, even from old incinerators, by the use of dust collectors between the burning units and the discharge stack. Most incinerator dust collectors in current use are either dry cyclones or simple washers. Neither of these devices is capable of removing particles less than 10 H in diameter from the flue gases at high efficiency, and neither is in any nner effective for smoke
and soot. Washers have the added disadvantage of cooling the Aue gases and greatly increasing their density by the addition of water vapor so that they lose their buoyancy when released to the atmosphere and fail to become dispersed and diluted as they do when released in a hot, dry state. High-energy scrubbers, electrostatic precipitators and industrial cleanable cloth filters are the only kinds of collecting equipment capable of reducing particle emissions from incinerators to a low level consistant with modern concepts of acceptable control of air pollution. Of the 3, industrial cloth filters are preferred because they are capable of cleaning the fue gases to the point where no visible emission occurs (greater than 99.9 per cent efficiency), and the cost is no greater than for electrostatic precipitation or high energy scrubbing. At present no municipal incinerator in the United States is equipped with any of these devices except for 1 or 2 small-scale pilot test units. In Germany electrostatic precipitators are used on combination coal-burning and refuse-burning municipal central-station steam plants, but they would have been required, in any case, for burning coal.
The equipment and installation cost of first-class Hy-ash collection equipment for an incinerator suitable for a city of 100,000 to 200,000 population is presently about $500,000. When amortized over the life of the incinerator (twenty or more years) this is just a few pennies added to the tax rate. Therefore, it is difficult to understand why affluent suburban communities are eager to build multimillion dollar, campus-type schools containing swimming pools and other amenities of modern "education" while remaining content to build new incinerators that have been obsolete for twenty years. Unlike education and dogs, waste disposal fails, so far, to arouse aggressive interest among the citizenry, but perhaps a current concern for maintaining the quality of the environment will change this attitude.
Even with the best possible dust collectors to remove all incineration fly ash and complete de struction of all organic matter by high-temperature combustion, contamination of the air may still occur from inorganic gaseous compounds. Oxides of sulfur are formed from the buming of sulfur-containing substances such as protein in food wastes and vulcanized rubber. Most of the sulfur will be in the form of sulfur dioxide, but a small percentage will be converted to sulfur trioxide, and this fraction combines with water vapor in the flue gases to form submicron-sized sulfuric acid mist droplets. Hydro gen chloride is formed during the burning of chlorine-containing synthetic plastics, principally polyvinyl chlorides. The occurrence of hydrogen chloride is increasing with the greater use of plastic materials of all kinds but is not yet thought to be a serious problem of air pollution. Oxides of nitrogen. principally' nitric oxide and nitrogen dioxide, are formed by the fixation of nitrogen from the air in the high-temperature combustion
Hydrogen chloride and sulfur dioxide can be utilization of heat produced in incinerators for muscrabbed from the flue gases with water and chem- nicipal purposes will continue but there appears to al solutions, but this may produce water-pollution be little interest on the part of United States utility problems unless proper provisions are made for the companies in utilizing this form of fuel. There are treatment and disposal of the waste waters. In ad- many technical reasons why this attitude is unlikely dition, the cooling of the flue gases interferes with to change in the foreseeable future. effective atmospheric dispersion. No satisfactory Composting. The practice of solid waste comprocess is available for the removal of nitrogen ox- posting is well developed in certain European Kthes from the hot, dilute incinerator stack gases, and countries, especially in Holland, Germany and atmospheric dilution and dispersal are the only Switzerland. The microbiologic degradation of ormeans now available to prevent the buildup of ex- ganic substances before return to the soil is a well cessive concentrations in the vicinity of the ground. established agricultural process, and when animal Because higher flame temperatures favor the fixation manure is composted with plant refuse, the product of larger amounts of nitrogen, high-temperature has fertilizer value and contains valuable soil conmodem incinerators form more of these compounds. ditioners. Municipal refuse collections in the United In most communities emissions of these inorganic States, composed largely of paper and lacking the gases from municipal incinerators are not regarded rapidly degradable organic component lost to the * a serious problem when they constitute the sole garbage grinder, contain little compostable matter. ao contaminants from these operations and when Consequently, compost made from United States they are emitted at high temperature from tall refuse collections contains virtually no fertilizer stacks
value, and its only uses are for ground cover and There has been considerable interest in the soil conditioner for heavy soils. It has about the United States in 2 European practices: extracting same properties as peat moss. American farmers useful heat from the burning of refuse; and com- have shown no interest in this product, for it is posting of solid wastes.
difficult to apply to fields by automatic machinery Heat recotery The heat content of typical Ameri- and the cost of spreading or working it into the soil on municipal refuse collections is about 5000 Brit- exceeds the benefits that may be obtained. Although ish thermal units (B.T.U.) per pound. When it is several experimental composting plants have operrealized that coals of various grades contain 12,000 ated for brief periods in the United States, they Do 14.000 BT.U. per pound, it is apparent that, in have been uniformly unsuccessful in disposing of the negregate, municipal refuse, composed largely of their product to farmers. It has been proposed that paper products, is a substantial fuel resource. In processors use the fiber for a carrier and diluent of Egrupe coal and oil have been relatively expensive highly concentrated chemical fertilizers, but it does u compared to their cost in the United States, and not seem that that the market for this product (to be this has made recovery of the fuel value in refuse used on lawns and gardens) will support more than cure attractive to the European countries. Also, the a few composting plants. Large-scale utilization of extra manpower required to burn trash has been composted waste would require acceptance by less of a burden in the lower-wage European econ- large-scale farmers, who are generally to be found say In addition, most of the European power- quite remote from the urban centers where the enerating stations that make steam from refuse are waste originates. Perhaps it could be managed if
una ipally owned, and this seems to make the each householder were willing to accept a bag of construction of combined conventional fuel and composted waste in exchange for his weekly refuse terba se-buming central stations more attractive than accumulation. w the United States, where it is more usual for European farmers are also not very enthusiastic power-generating stations to be operated by private about compost from municipal refuse, but some utility companies or by regional governmental au- have been persuaded to accept it when the price is thorities that have no responsibility for refuse col- not much in excess of the cost of transporting it lection and disposal. There are exceptions, however. from the composting plant and the fertilizer value of The Boston Municipal Incinerator, completed a few the product has been raised by the addition of sewyear ago, produces steam for the adjacent Boston age sludge to the raw refuse. The heat generated by Cây Hospital. Although the incinerator must burn the microbiologic activity of composting is sufficient substantial quantities of supplementary fuel to meet to destroy disease-producing bacteria in the sludge te hospital's total requirements (in part, because after a few days, and the mixture is safe to put back the heat-release rate of the refuse has not been as on the soil after a few months of aging. Many Eurogreat a was estimated originally) some of the heat
peans see composting of municipal refuse primarily value to the refuse is being recovered. Many United as a means of disposing of sewage sludge, presently States incinerators utilize heat in the flue gases to a grave problem in central Europe. Many advocates prwide space heating and hot water for the incin- of composting in the United States, including Tutor plant, and a new incinerator on Long Island, manufacturers of composting machinery, have tended New York, is equipped to use waste heat to desali- to stress financial gains from selling the end product. mate sea water by distillation. It is likely that the This is probably a mistake because the income
from selling composted refuse is always likely development. One, utilizing an iron-melting cupola,
able commercially, but the cost will be high.
these were salvaged, and some joined the 25,000.-
automobile in the United States contains about 142
A newer way of handling stripped automobile
NONURBAN SOLID-WASTE PROBLEMS
all kinds and the severe disturbances to ground and
1. American Public Works Assixiation, Committee on Solid Wastes
Refuse Collection Practice. Third edition. Chicago: Public Admin-
istration Service. 1966. P. 27
Presented on September 12, 1966. before Public Works Congress
sponsored by American Public Works Assoxiation, Chicago, Illinois.
plosive hazards in buildings crected on landfills, Pub. Health Rep.
Panel. Restoring the Quality of Our Entrronment. The White House,
November, 1965. P. 17.
Science, Research, and Development, înted States House of Re-
Printing Office, 1966. P. 44
Committee on Pollution. Waste Management and Control: A report to the
tional Research Council, 1966. (Pub. No 1400.) P. 32.
Second edition. Chicago. Public Administration Service, 1966 P. 42.
tation for incineration. Presented at 1966 National Incinerator Con-
New York, May 2, 1966.
Copyright, 1966, by the Massachusetts Medical Society
Printed in the U. S. A.
Senator MUSKIE. The next witness is John C. Collins, director, division of environmental health and chief sanitary engineer for the Massachusetts Department of Public Health. It is a pleasure to welcome you, sir.
STATEMENT OF JOHN C. COLLINS, DIRECTOR AND CHIEF SANITARY ENGINEER, MASSACHUSETTS DEPARTMENT OF PUBLIC HEALTH
Mr. COLLINS. Delighted to be here, Senator.
Mr. COLLINS. No; but I am sure if we reach far enough back, there is a relation. [Laughter.]
Senator MUSKIE. Well, I associate Boston with family dynasties for some reason. [Laughter.]
Mr. Collins. My dynasty is from north of Boston.
Mr. Collins. I have a prepared statement here and, of course, I would be delighted, after, to answer any questions which I may be able to.
I would like to point out that my remarks will be directed primarily to Massachusetts and the problems that we have here in Massachusetts.
The Massachusetts Department of Public Health has been greatly concerned for a number of years with the solid waste problem. I imply by that that we have had a great deal of involvement over the years. The department places a very high priority on the need for recognition of and resolution of this so-called "third pollution.” The present insanitary management of solid waste disposal creates not only sources of environmental pollution and nuisance conditions but provides a continuing potential for disease transmission.
Within the State the activities of the department primarily center around two pieces of legislation. One is a permissive piece of legislation allowing for regional approaches, development of regional facilities by municipalities. It is interesting to point out here that this was enacted in 1965, but as of this date no regional disposal facility has been established.
The other piece of legislation provides more or less a concurrent authority. It provides for an assignment of a site for a disposal facility by the local board of health, but allows the department of public health to hold public hearings in the event of problems with the operation of the facility.
I think it is particularly interesting that over the last few years the department has found it necessary to modify the assignment in many communities and require the elimination of the open-burning dumps and require the operation of the disposal site as a sanitary landfill.
One hearing held under the provisions of this legislation concerned a privately owned and operated commercial solid waste disposal facility serving some 15 communities, thousands of business establishments, institutions and similar agencies and numerous private-commercial refuse collectors throughout the Metropolitan Boston area.