No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Wastewater treatment alternatives for municipalities along a stream system
Canadian Journal of Civil Engineering
Abstract
Since 1978, the government of the province of Quebec has undertaken an important water pollution control program. Under this program, new wastewater treatment plants are to be constructed in many municipalities of the Yamaska watershed (Quebec) by 1990. From an engineering point of view, one of the major issues in planning the construction of these treatment facilities is the selection of the wastewater treatment alternatives to be implemented at each municipality of the watershed. Using case studies from the Yamaska watershed, the present study illustrates the role and importance of three factors for the analysis and the selection of wastewater treatment alternatives. These factors are (1) the standards, as related to the receiving stream, (2) the discharge point interactions through the receiving stream system, and (3) the various possibilities for joint or separate treatment of municipal and industrial wastewater. Examples are given of the economical implications that may result from these factors. While each factor was dealt with separately for the purpose of this study, it is clear that they are strongly related and that they interact. As a result, the selection of wastewater treatment alternatives is fundamentally a system-based problem rather than a case-by-case problem. Key words: wastewater treatment alternatives, treatment process, standards, receiving stream, stream system, joint treatment, separate treatment, wastewater treatment costs, decision analysis, systems analysis, Yamaska River, urban wastewater, industrial wastewater, economical implication.
... Cost functions are linear, although the authors show, for the cases tested, that the error due to linearization is minor. PINEAU et al. (1985) andLÖWGREN et al. (1989) performed a comparative analysis between local and central solutions, confronting different technologies. However, their aim is more to gain insights into the structure of the problem, than to actually optimize a regional system. ...
The problem of the optimization of regional wastewater systems may be generally formulated as follows: to define the transport and treatment system in a region or water basin, which assure compliance with given pollution control criteria, with minimum cost. In addition, one may try to satisfy other objectives, such as minimum environmental impact, better effluent reuse or adequate phasing. From the optimization point of view, the two main problems that render the solution difficult are the dimensionality and the concavity of cost functions. The matter has been dealt with by many authors, who have produced varied techniques to try to solve this problem. This paper begins with a brief review of the work of those authors who have produced models specifically designed to study the problem. Then, solution strategies are discussed concerning three major items: definition of the objective function and constraints, optimization method and practical applicability of the models. The paper concludes with the discussion of topics for future research.
Injections of NO3 and PO4 were made during September 1975 into Little Lost Man Creek, a small pristine stream in Redwood National Park, California. Chloride, a conservative constituent, was added in a known ratio to the nutrients. Nutrient loss at a downstream point was calculated using concentration of added Cl as a reference. Nitrate nitrogen (NO3-N), added for 4 h, reached 920 μg/1 (above 5 μg/1 background) just below the injection point, but increased only to 405 μg/1 at 310 m downstream. The concentration decrease was attributed to dispersion and to uptake by stream biota. Percent of NO3-N lost decreased with increasing concentration of NO3-N. Phosphate phosphorus (PO4-P) was added a week after the NO3-N for 3 h, causing a concentration increase of 296 μg/1 (above 13 μg/1 background) just below the injection point, of 161 μg/1 at 90 m downstream, and of 98 μg/1 at 310 m. Percent loss of PO4-P at downstream sites increased with increasing PO4-P concentration and also for a short period after peak concentration occurred, but then decreased as PO4-P concentration continued decreasing. Differences in stream response to added NO3-N and PO4-P are attributed to differing rates of reaction with biota and differing degrees of interaction with abiotic stream solids.
1.1. An examination of river survey data showed standing crop of Cladophora to be correlated with phosphorus concentration. In general, river water containing less than 1·0 mg l−1 total inorganic P produced only modest growths of Cladophora.2.2. Culture experiments with supplemented river water confirmed the importance of phosphorus by showing that growth of Cladophora in waters upstream of sewage discharges, could be increased to downstream levels by addition of phosphorus.3.3. Growth experiments in synthetic media containing levels of phosphorus from 1 to 7 mg l−1 indicated no significant growth increase above 1 mg P l−1 but a significant reduction below 1 mg P l−1.4.4. In natural water, the maximum level of phosphorus for growth was found to vary, being 2·5 mg P l−1 at 3·2 mg N l−1 NO3 and 0·95 mg P l−1 at 5·25 mg N l−1 NO3.5.5. A 3 × 4 factorial experiment utilizing synthetic media, confirmed an interaction between nitrogen and phosphorus. The highest level of NO3 (7·7 mg N l−1) enhanced growth at the lowest phosphorus level (0.5 mg P l−1) but at higher levels of phosphorus growth was reduced.6.6. The importance of such interactions is discussed briefly in connection with eutrophication and nutrient stripping.
During recent years the activities for removal of phosphorus from sewage effluents have increased to a very high degree of intensity in those countries, where the phosphorus is one of the major factors contributing to man-made eutrification. The most successful approach to achieve this has been the erection and operation of plants for chemical treatment of the sewage. There already are many plants operating e.g. last year in Sweden ⋍110, Finland ⋍45, Switzerland ⋍40. The discussion will be limited to chemical and physical operations in plants of this kind.Primary precipitation, secondary precipitation, simultaneous precipitation, pre-precipitation, post-precipitation and some techniques used for a single house or a small group of houses in rural and resort areas are considered. Particular design features, choice of chemicals, performance data, investment costs and operational costs are presented.It is shown, that the removal of phosphorus, including the detergent phosphates, can be carried out efficiently and to very reasonable costs. A decrease in the phosphate content of the detergents does not give a proportional cost reduction in the treatment plant. Not only phosphorus but also BOD, suspended solids, bacteria, viruses, intestinal worm eggs and heavy metals are substantially reduced in the effluent water.Some consideration is given to the sludge problem and the relationship between detergent composition and the performance of a treatment plant.
Wastewater engineering-treatment, disposal and reuse. McGraw-Hill series in Water resources and environmental engineering
- Metcalf And Eddy Inc
METCALF AND EDDY INC. 1979. Wastewater engineering-treatment, disposal and reuse. McGraw-Hill series in Water resources and environmental engineering. 2nd ed. McGraw-Hill.
Assai-nissement urbain Factors affecting growth of rooted aquatics in a river
- Ministere De L 'environnement Du Quebec
- Meq
- Montrtal
- Qut
- W H Peltier
MINISTERE DE L'ENVIRONNEMENT DU QUEBEC. 1984. Assai-nissement urbain. MEQ, Montrtal, Qut. PELTIER, W. H., and WELCH, E. B. 1969. Factors affecting growth of rooted aquatics in a river. Weed Science, 17(4), pp. 412-416.
Computer program documentation for the stream quality model QUAL-11. Prepared for the United Stations Environ-mental Protection Agency, Systems Development Branch, by WRE Synthesis of waste treatment system by implicit enumeration
- A L Monser
- J R Evenson
ROESNER, A. L., MONSER, J. R., and EVENSON, D. E. 1977. Computer program documentation for the stream quality model QUAL-11. Prepared for the United Stations Environ-mental Protection Agency, Systems Development Branch, by WRE, Walnut Creek, CA. ROSSMAN, L. A. 1980. Synthesis of waste treatment system by implicit enumeration. Journal of the Water Pollution Control Federation, 52( I), pp. 148-160.
Downloaded from www.nrcresearchpress.com by University of P.E.I
- Can J Civ
- Eng
Can. J. Civ. Eng. Downloaded from www.nrcresearchpress.com by University of P.E.I. on 11/15/14 For personal use only.