Chemical changes and leachate mass balance of municipal solid waste bottom ash submitted to weathering

A study on the chemical stability of municipal solid waste (MSW) bottom ash submitted to weathering was carried out in order to identify and quantify the physico-chemical maturation mechanisms in a large heap (375 tonnes) over a period of about 18 months. The mineralogy and chemical composition of MSW bottom ash were analysed on fresh and maturated material. Calcite is the predominant newly formed mineral during bottom ash maturation, combined with aluminium hydroxides and various sulphates. Lead and zinc are trapped primarily by newly formed carbonates. Monitoring of the pore water and the outlet leachates revealed a marked contrast in the physico-chemical conditions within the heap and at the outlet. The salinity of the fluids peaked at around 16 g/l within the first few weeks and then progressively decreased to fluctuate between 5 and 8 g/l. Due to the high pH of the pore water, the average concentrations of heavy metals in the heap are high: 42.7, 9.6 and 0.8 mg/l for Cu, Pb and Zn. At the heap outlet, however, the leachates are buffered by carbonate precipitation due to equilibration with atmospheric CO2. Copper complexed as a chloride at the outlet remains at a relatively high concentration (10.2 mg/l), whereas Pb and Zn concentrations are below the limit of detection (<25 microg/l). A mass balance carried out over the 18 months of monitoring indicated that 86% of remobilized material within the heap is evacuated from the system. Within the heap, carbonation trapped 43 and 54% of the calcium and bicarbonate flux. The copper, lead and zinc flux at the heap outlet represent only 34, 18 and 19% of the actual remobilized mass of heavy metals.     

Detection and enumeration of colonic mucosal cells in amniotic fluid using a colon epithelial-specific monoclonal antibody

Since its introduction, prenatal diagnosis of chromosomal and metabolic disorder by mid-trimester amniocentesis has relied upon the use of a mixture of fetal cells obtained from amniotic fluid. Little knowledge has been gained in the sorting of these cells for diagnosis of tissue-specific disorders. In an attempt to determine the contribution of fetal colonic mucosal cells to the overall amniocyte population, we used the colonic epithelial-specific monoclonal antibody (MC-Ab) 7E₁₂H₁₂, IgM isotype. Specimens of the small intestine, colon, buccal mucosa, kidney, urinary bladder, and umbilical cord were obtained from electively aborted normal fetuses of 12–28 weeks' gestation. All of these specimens were examined with 7E₁₂H₁₂ by the immunoperoxidase technique. The MC-Ab reacted with the colonic epithelial cells but not with any of the other tissues. In addition, 40 amniotic fluid samples obtained from women between 16 and 18 weeks of gestation, who underwent amniocentesis because of advanced maternal age, were tested using a fluorescent activated cell sorter. Among the amniotic fluid specimens examined, 18·4 ± 10·3 percent cells reacted with 7E₁₂H₁₂. Double immunofluorescence studies revealed that all Mc-Ab-stained cells contained secretory component, confirming that they were epithelial in origin. All fetuses whose amniotic fluid was analysed had normal karyotypes and amniotic fluid alpha-fetoprctein levels that were also normal. This study demonstrates that cell-specific Mc-Ab can be used to detect colon cells in the amniotic fluid and that colon cells contribute significant numbers in the mixture of amniotic fluid cells. This technique could be helpful in the prenatal diagnosis of disorders in which the flow of amniotic fluid through the fetal intestine is impaired, such as cystic fibrosis, imperforate anus, Hirschsprung aganglionic megacolon, and intestinal atresia.     

Plants Pollute Air

A recently developed photometer utilizes near-forward scattered light to count and size aerosol particles in the diameter range 0.3-17 μ. The particles are drawn through a 1-cu mm illuminated volume without entering the body of the optical chamber. Hence, purging is almost instantaneous, and number concentrations below 1,000,000/cu ft give less than 3% coincidences. The scattered light pulse from each particle is detected by a photomultiplier tube. The resultant voltage pulses are amplified, measured by a series of ten discriminator circuits, and stored in a series of ten 5-decade electronic counters. At the end of a chosen period ranging from 1/3 to 30 min, a digital printer prints the number of particles at each diameter. At the end of the printout, the procedure automatically recycles. The instrument provides ten size classifications, each successively having a width ratio of 1.5 to 1. Greater precision is seldom practical since most aerosols contain particles of different refractive index, color, and shape, all of which affect the intensity of the scattered light. Calibration is accomplished with aerosols of uniform size such as spray-dried polystyrene and other latex suspensions, supplemented by calculations based on the Mie theory of light scattering.     

Glass Fibers and Their Use as Filter Media

Typical air quality effect levels of photochemical oxidants on specific plant substrates are illustrated. These include ambient oxidant exposure data measured as “total oxidant” as well as laboratory exposures to individual pure oxidants, ozone, or PAN compounds, since these oxidants are identified in photochemical smog. New terms, “PaNs” and “PAN-type” oxidant, have been proffered for purposes of clarification of the terminology. PAN-type oxidant more precisely defines the phytotoxicant complex causing silvering or bronzing of the lower leaf surfaces in lieu of the older term “oxidant.” Due to the recognition of several oxidizing phytotoxicants in recent years, it is recommended that the term oxidant be reserved for use as a generic term. A tabular classification of the oxidizing phytotoxicants found in community photochemical smog and the specific syndromes produced is provided.     

Black Liquor Oxidation as a Method for Reducing Air Pollution from Sulfate Pulping

This paper will discuss the sources of odorous air pollutants from sulfate pulping operations. One of the major sources is the recovery furnace. Odors from this source can be reduced considerably by oxidation of the black liquor prior to evaporation and burning. The procedure has been used with considerable success in the northwestern and northeastern parts of the United States. Unfortunately, the majority of sulfate pulp production occurs in areas where southern pine is the basic raw material. For several reasons the black liquor resulting from southern pine operations presents problems when the usual oxidation procedures are used. Although not as effective as normal black liquor oxidation strong black liquor can be oxidized without too much difficulty. Various procedures for oxidation of black liquor will be discussed. Results of stack sampling in U. S. pulp mills with and without the oxidation unit in operation will be reported.