Journal of Environmental Engineering

A deterministic Linear Programming Model is presented for development of acid rain abatement strategies in eastern North America. Pollutant $\left({\mathrm{SO}}_2\right)$ sources are categorized as either controllable or noncontrolled, (i.e., area sources). The model determines the least‐cost set of ${\mathrm{SO}}_2$ removal levels at each of the 235 largest point sources in eastern North America, such that stipulated maximum wet sulfate deposition rates are not exceeded at 20 predetermined sensitive receptor locations. Emphasis is placed on the model's flexibility with respect to input data requirements and its ability to conveniently and efficiently accommodate varying constraint formulations. Model applications are presented which involve five different constraint formulations.

Land treatment is a managed treatment and ultimate disposal process that involves the controlled application of a municipal or industrial waste to a soil or soil‐vegetation system. This technology is based upon scientific and engineering principles and field experience. This paper describes the limiting constituent concept that is the basis of successful design and operation of land treatment systems, identifies how the concept can help determine pretreatment, monitoring, and feasibility decisions, and uses four case studies to illustrate the applicability of the technology to industrial wastes and to sludges.

Heavy metals analysis was performed on the sediments from various south Louisiana waterways. Objectives of the study were to determine vertical heavy metal distributions, to evaluate a proposed statistical method used to make qualitative assessments of cultural contamination based on trace metalconservative metal relationships, and to attempt to determine heavy metal contamination in sampled sediments. Cores were obtained from three distinct areas in south Louisiana. Area 1 consisted of waterways located in heavily industrialized areas. Area 2 sample consisted of a 110 m deep core obtained just off the present Mississippi River delta. Area 3 samples were obtained from a shallow urban lake. The vertical metal concentration distribution of the deep core revealed very consistent concentrations for metals throughout the entire depth. The relative atomic variation (RAV) method, used to reduce the grain size effects on heavy metal accumulations in sediments by correlating element pairs, was evaluated. The evaluation of the method in this study uncovered serious limitations. Metal contamination was determined by comparing both absolute concentrations and trace metal‐conservative metal concentration ratio values to their respective deep core background values.

A method for the optimal expansion of water distribution systems subjected to a single loading pattern is developed. The method optimally decides the pumping heads at new source nodes, if any, and also optimally selects the links which need strengthening to improve the delivery capability of the existing system. The method is iterative and converges rapidly to a local but fairly good optimal solution. Optimization of an entirely new distribution system is a particular characteristic of this general approach. Examples of the method are given, including its application to the expansion of the New York City water supply tunnel system. The possible extension of the method to time‐varying demand patterns is also described.

Recently, a high‐volume horizontal elutriator with a flared inlet was developed to monitor inhalable particulates in the ambient air. Preliminary results of a study to evaluate the performance of the horizontal elutriator under nonstill air conditions are presented. Collection efficiency data were obtained for monodisperse aerosols with particle sizes of 4.0, 9.25, 20.0, and 30.7 μm aerodynamic diam. Experimental results indicate that the device does not meet the established performance criteria. The main cause of nonperformance is probably a combination of exterior turbulent propagation into the initial part of the elutriator, nonisokinetic sampling conditions and particle diffusion.

Implementation of water conservation programs can result in significant savings to water utilities. Engineers and planners working with utilities need to be able to predict the reduction in water requirements (i.e., effectiveness of water conservation) that will result from implementation of water conservation measures. A procedure that was developed to help predict water conservation effectiveness for typical conditions is presented.

For the design of sewers nomograms are available in the literature for various flow equations. These nomograms can be used only for the condition when the depth of flow is full diameter of the sewer. The sewers are invariably designed to flow only for partial depths. For design of sewers involving determination of velocities and discharges under partial flow conditions another graph, depicting the relationship between ratios of depths of flow and ratios of discharge and velocity when flowing partially and those when flowing full, is required in conjunction with the above nomograms. The conventional method for solving a problem under partial flow conditions of a sewer involves six steps consisting of arithmetical calculations and reference to more than one chart or graph. The time and effort required for a designer are thus considerable. A nomogram is developed to eliminate all the tedious procedures involved in the conventional method. The required parameters can be directly read on the nomogram with reasonable accuracies for flows between 0.25 and 0.75 diameters.

In the conventional method of calculating the fractional removal of flocculent particles, it is assumed that the average settling velocity for different particle sizes in the lower depths in settling basins is the same as in the upper depths. This assumption is not quite correct, because the particles continuously flocculate or shear during the entire settling depth, and hence the average settling velocity changes both with depth and time. In the modified method, a different approach for calculating the fractional removal of particles is proposed to overcome the deficiency in the conventional method. Instead of considering a vertical constant time line, a horizontal constant depth line for that particular time is used. This approach is more reasonable because the settling velocities of different flocculating particles are all averaged over the same depth.