A Thermodynamic Analysis of a Primary Waste Stabilization Pond

Traditional design practice for waste stabilization ponds is based upon the premise that sufficient photosynthetic oxygen must be produced within the pond to satisfy oxygen requirements of the incoming waste flow. Thus, because algae production is proportional to pond surface area, surface organic loading rate is a principal design criterion (hydraulic detention time is the other) . That a possible adverse energy trade exists in the sequence of coupled reactions (aerobic waste degradation-photosynthesis) has been largely ignored. This work is focused on quantitatively articulating this energy trade, in terms of algae produced vis a vis waste degraded. This is done by: (1) defining the chemical reactions involved-both stoichiometrically and thermodynamically (the latter in terms of equilibrium conditions), (2) measuring terms in a daily mass balance model of an operating primary pond, and (3) evaluating the algae production potential for the pond studied, based upon available solar insolation. These results define respectively, (1) the calculated absolute lower limit of daily algae synthesis necessary for production of the stoichiometric oxygen to satisfy the daily influent BOD requirement, (2) a measured daily synthesis rate of algae to compare with the daily influent TOC (total organic carbon), under conditions of maximum sunshine in the annual cycle, and (3) the calculated absolute upper limit of daily algae synthesis, through the annual cycle, if all usable solar energy were utilized. Results, for a daily waste inflow of 415 kg Toe, showed: (1) 167 kg per day of algae TOC must be synthesized to provide the stoichiometric oxygen for 415 kg TOC waste, as glucose, (2) measured algae synthesis rate, in early July, was +12,600 kg TOC per day, and (3) algae production potential in early July was 44,000 kg algae TOC per day. The effluent flux was 110 kg TOC per day

Planning water reuse: development of reuse theory and the input-output model. Volume II, Application of the input-output water balance model

Submitted to Office of Water Research and Technology, U.S. Dept. of the Interior.September 1980.Includes bibliographical references.OWRT project no. 78-270450-145

Salt balance analysis

December 1983.Bibliography: page 79.Project no. A-051-COLO, agreement no. 14-34-0001-1106, 14-34-0001-2106; partially funded by the U.S. Dept. of the Interior, as authorized by the Water Research and Development Act of 1978

Salt transport in the river

December 1983.Based on Gomez-Ferrer's thesis (M.S.)--Colorado State University, 1981.Bibliography: pages [68]-71.Project no. A-051-COLO, agreement no. 14-34-0001-1106, 14-34-0001-2106; partially funded by the Office of Water Research and Technology, project no. 53-1690 and Colorado State University Experiment Station, project no. 15-3141

Salt transport in the lower South Platte River

CER81-82RVG-DWH35.Environmental Engineering Technical Report No. 82-3141-01.Project 15-1372-3141 Water Quality Problems of Colorado, Colorado State University Experiment Station.Project 53-1372-1690 Dissolved Solids Hazards in the South Platte River Basin, Colorado Water Resources Research Institute.Includes bibliographical references (pages 68-81).January 1982.This work demonstrates how river salinity may be characterized, in terms of both time and space variations. Fifteen years of daily and monthly salinity and flow data have been reduced to monthly, seasonal, and annual statistical characterizations for five river stations and three tributary stations for the lower South Platte River. From these characterizations distance profiles were plotted for flow, TDS, and salt mass flows. The distance profiles and measurements of diversion flows, tributary flows, and point source discharges were the basis for a reach by reach materials balance analysis for four reaches of the South Platte River between Henderson and Julesburg. Return flows and return salt mass flows were computed as residuals. The analysis showed that there is not a salt balance in the lower South Platte River. A net salt loss to the land of 380 tons per day occurs by irrigation. The analysis provided can be the basis for a more comprehensive materials balance model. But the results can be used to estimate the impact of new water resources developments upon the salinity regime of the lower South Platte River

Sorption Kinetics Part II: Modeling Longitudinal Concentration Profiles in a Packed Bed Reactor

A mass balance simulation model for sorption in a packed bed reactor was developed. All of the terms in the model, consisting of constants of the porous media, and functions, were evaluated by independent laboratory studies. The kinetic term was determined in Part I. Two numerical schemes (an explicit scheme and an implicit scheme respectively) with corresponding computer programs were developed and made operational. They were not tested against laboratory column results due to long times necessary on the computer and corresponding high costs. Laboratory testing consisted of measuring column profiles for six different packed columns at different flow rates and feed concentrations and for two sorbents, Dowex 50 resin and Filtrasorb 200 activated carbon. Further Kinetic studies were also conducted on the problem of whether sorbate delivery rate by bulk convection is rate controlling. This was termed “transport kinetics” and comprised a part of the simulations model

Sorption Kinetics Part I: A Laboratory Investigation of Six Proposed Rate Laws Using Batch Reactors

Six proposed rate equations for sorption kinetics have been investigated by laboratory batch experiments involving some 270 individual “runs” to determine sorption uptake with time for varying conditions of initial sorbate concentration, temperature, and sorbent species. The sorbate selected was rhodamine-B dye, used because it will sorb readily and is easily measured. Two sorbents, Dowex 50 resin, and Filtrasorb 200 activated carbon were used. Temperature conditions were 10, 20, 30, and 40°C, and concentrations ranged from .0008 to 400 micrograms per ml, rhodamine-B. Analysis of data was computer automated, requiring as input only test conditions, instrument readings, dilutions, and corresponding time. Output of the program for a “set” of data included three different kinds of plots, determination of Langmuir isotherm constants, carious statistical fits, and calculation of rate coefficients for each of the six proposed rate equations along with commensurate plots and statistical analyses. Results indicated that one rate equation in particular showed high R2 correlations with test data. Further analyses established the rate coefficient for this equation in terms of degree of sorbent saturation with sorbate, sorbate concentration in solutions, and temperature of solution

Analysis of Water Reuse Alternatives in an Integrated Urban and Agricultural Area

Intoduction The growing demands on our existing water supplies and the current problems of water shortage emphasize the need for a comprehensive approach to analysis and planning of water reuse. The primary focus, heretofore, has been on the treatment technology for achieving water reuse. The concept of reuse, however, should be broadened to consider a totally integrated urban and agricultural system. This necessitates a systems analysis where water reuse, together with all other water dispositions, is considered in the context of its contribution to the total water resources pool of a region. The components of the water resource system are shown in the matrix of Figure 1, including both sources of sources are indicated by row headings, and each origin of water is classified as : (1) primary or base supply, (2) secondary or effluent supply, or (3) supplementary or imported supply. Each row represents a different possible origin of supply. The system of water users is indicated by the column headings in Figure 1. They are grouped into the broad sectors of municipal, industrial, agriculture demands, or other uses. Both the sectors of water use, the columns, and the supply categories, the rows, can be specified to any degree of refinement desired. In the context of broad system planning, the matrix of water supply sources and demand sector requirements depicts all possible combinations for satisfying the aggregate system demand with the aggregate available supply. Thus, each element in the matrix represents a possible means of satisfying all or part of the demand requirements of a sector with all or part of the water from a given source. In the past water planning and management has been concerned mainly with the design and optimum operation of storage and distribution systems to regulate water allocation to each use sector in both time and space. This approach is generally adequate when water resource development is at a stage where the primary water supply is in large excess of demand requirements, and the entire demand can be satisfied by the primary supply vectors. However, in many areas the primary supply is no longer sufficient to meet the diversion requirement of all users. Thus, secondary and supplemental sources of water become important, and water demands must be met by recycle-reuse and sequential-reuse from secondary supply vectors or development of supplementary supplies. This means that all combinations in the matrix of Figure 1 need to be considered for comprehensive planning of water utilization. The purpose of this paper is to delineate the manner in which all system permutations can be explored and how the best alternatives can be selected. Specifically, the objectives are: 1. To formulate a conceptual framework for analyzing water reuse alternatives. 2. To present a model for analyzing alternatives of sequential-reuse and recycle-reuse in an integrated agricultural and urban environment. The function of the model is to determine the optimal allocations of water from each supply category to each use sector at minimum cost, which is the focus of this paper, or maximum net benefits. Quality constraints may necessitate treatment of water before reuse. Therefore, three possible levels of treatment are considered in the analysis: (a) conventional primary-secondary, (b) tertiary, (c) desalting. 3. To illustrate the application of the reuse model by application to a specific metropolitan area. Some questions to be answered are: 1. Which origins of primary and secondary water supply might best be allocated to which use sectors, considering quantity and quality constraints of minimum costs? 2. What should be the design capacities of waste water treatment facilities and when should they be phased into operation