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Waste sorts were conducted during each of the four quarters (or seasons) of 1996 at the City of Columbia Sanitary Landfill. A detailed physical sampling protocol was outlined. Weight fractions of 32 waste components were quantified from all geographic areas that contribute to the Columbia Sanitary Landfill using a two-way stratification method, which accounted for variations in geographical regions and seasons. Comparisons of solid waste generated between locations and seasons were conducted at the 80% confidence level. The composition of the entire waste stream was 41% paper, 21% organic, 16% plastic, 6% metal, 3% glass and 13% other waste. Paper was the largest composition and glass was the smallest composition for all geographical regions. The result of this study was also compared with a 1987 Columbia, Missouri study conducted by EIERA (1987), with studies conducted in other states such as Minnesota, Wisconsin, Oregon and with national study conducted by the USEPA (USEPA 530-R-96-001, PB96-152 160. US Environmental Protection Agency, Office of Solid Waste, Washington, DC). The results of studies from other states are different from this study due to different local conditions, different methodologies and a different scope. There was a small (5%) increase in per capita weight from 1987 to 1996. The total per capita weight in the present study was 60% greater than the national per capita weight reported by the USEPA (1996) due to that the USEPA report excluded industrial, construction and certain commercial waste. The total per capita weight agrees with the national per capita weight for municipal waste reported by Tchobanoglous (1993), which included industrial, construction and commercial sources. The geographical and seasonal effects on the waste composition are evaluated and discussed. Statistical analysis indicates that waste characteristics are different among geographical regions and seasons. The potential for waste recovery and reduction is also discussed.

That water quality changes are related primarily to the oxidation of iron metal was indicated by results of an experiment with a simulated pipe loop system using tap water. A variety of aquatic microorganisms was observed and identified in the pipe loop system, among them the organisms that constitute the microbiotic cycles of carbon, nitrogen, sulfur, and iron transformation. With microbial growth, cast iron test specimens exhibited localized corrosion.

Because of an increasing need to balance health risks for pathogen control and disinfection by-product (DBP) formation in water supplies, utilities are forced to closely examine and optimize their disinfection practices. The authors provide a simple mechanistic model to predict total trihalomethane (TTHM) and the sum of nine haloacetic acids (HAA9) formation based on chlorine demand. To evaluate this modeling approach, eight Missouri surface waters (raw and alum-treated) were used in DBP formation and chlorine decay kinetic studies. A parallel first-order reaction model was used to fit the chlorine decay data, and the model coefficients were used to predict THM and HAA formation.Yield coefficients for TTHMs and HAA9 were obtained from fitting the DBP kinetic data. On average, the TTHM and HAA9 yield coefficients for all raw surface waters tested were about 40 µg TTHM/mg Cl 2 and 25 µg HAA9/mg Cl 2 consumed, respectively. In waters subjected to alum coagulation, the average TTHM and HAA9 yield coefficients were 30 µg TTHM/mg Cl 2 and 17 µg HAA9/mg Cl 2 consumed, respectively. The DBP predictive model introduced in this study provided a simple, reliable basis to evaluate treatment options by focusing on chlorine demand. This model can be readily calibrated to local conditions.