1887

n Journal of the South African Institution of Civil Engineers - Applying constrained optimization to water supply and demand management : technical paper

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Abstract

A planning and forecasting model for the Umgeni system uses constrained optimization to indicate resource availability and the consequent reduction required in the demand. The constrained optimization equations are developed to include general operating strategy, such as when to use inter-basin transfers or water from lower quality resources that cost more to treat and deliver. Constraints and boundaries are set out and the method of solving the problem of spillage from the reservoirs is explained. Results are quoted showing the improvement of optimization over simulation using both generated and actual data. An alternative approach is to control the demand by price. It is possible to develop a general constrained optimization model to ascertain the feasibility of such actions. The objective function for this second constrained optimization model is described. Cost functions are developed encompassing different aspects of effluent quality using surrogates. General equations of industrial use are indicated. In an area where water is scarce extreme measures may be adopted. All this results in the initial demand being reduced. However, safeguards are needed because the cost of failure of the system to industry is high. Alternative uses of the second model are suggested.

'n Beplannings- en voorspellingsmodel vir die Umgenistelsel maak gebruik van begrensde optimisasie om bronbeskikbaarheid, en die gevolglike vermindering in aanvraag, aan te dui. Die begrensde optimisasievergelykings word ontwikkel, om algemene operasionele strategie in te sluit, soos wanneer om van inter-opvanggebiedoordrag of van water van laer gehalte-voorsieningsbronne gebruik te maak, wat 'n verhoogde koste vir behandeling en aflewering tot gevolg het. Newevoorwaardes en grense word uiteengesit en die metode om die probleem van oorvloei van die reservoirs op te los, word verduidelik. Resultate, wat 'n verbetering van optimisasie in vergelyking met simulasie toon en wat gebruik maak van kunsmatige en werklike data, word aangehaal. 'n Alternatiewe benadering is om die aanvraag deur middel van prys te beheer. Dit is moontlik om 'n algemene begrensde optimisasiemodel te ontwikkel om die wenslikheid van sulke matreels vas te stel. Die objektiewe funksie van hierdie tweede begrensde optimisasiemodel word beskryf. Kostefunksies, wat die verskillende aspekte van afvloeikwaliteit insluit, word ontwikkel deur van surrogate gebruik te maak. Algemene vergelykings vir industriele gebruik word aangedui. In 'n gebied waar water skaars is, kan uiterste maatreels aangeneem word. Dit alles het 'n vermindering in die aanvanklike aanvraag tot gevolg. Beveiliging is egter benodig vanwee die koste wat dit vir die nywerheid meebring indien die stelsel sou faal. Alternatiewe gebruike van die tweede model word voorgestel.

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/content/civileng1/35/4/EJC26719
1993-01-01
2016-12-05
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