The City of Tatooine approached you to develop a design for a small water treatment plant to meet the drinking water demand of its growing population of 75,000 people. The City grows on an average of 2% per annum with a major industrial customer (industry to be selected for each group is given at the end of the Assignment sheet). The City’s residents are highly critical of their current water quality which is sourced from a nearby lake. The main concerns are:
• Cloudy water
• Poor taste and smell at times of the year
• Occasional gastroenteritis experienced by the children and the elderly
• Visiting tourists consider the water quality as pathetic.
The following information is provided as guidance to design the water treatment plant. You are encouraged to source other relevant information and provide reference for each of the assumptions made. The plant design should take into account the capital and ongoing operational costs for the City to be able to sustain increased expenditure over the next 25 years.
Develop a table for the water quality parameters of surface water (rivers and lakes), and groundwater. A sample table is given below:
Water quality parameters of different source waters
Parameter River water Lake/reservoir water Ground water
Total organic carbon
A typical water quality of the source water is provided in the table below. Identify the possible source of the water. What other water quality information that you would like to have for the design of the water treatment plant?
Comment on each of the raw water parameter’s significance in relation to the selection of appropriate water treatment process.
Sketch a flow diagram of a treatment process to produce an acceptable quality of water all year around. Indicate the chemicals used, expected dosages required and detention times. Give reasons for each of your statements.
Water treatment system among other process will contain the following and you are required to design only one of them and demonstrate strong understanding of the principles involved in the design of each unit process.
• Coagulation, Flocculation and Sedimentation Group (I), (IV) and (VII)
• Filtration, backwashing and Disinfection Group (II) and (V)
• Sludge handling and disposal options Group (III) and (VI)
You are also expected to implement the practical issues discussed in the lecture series into your designs.
I Coal mining
II Meat processing
III Automobile manufacturing
IV Garments industry
VI Building materials
VII Multi-media (Printing/Electronic)
Determine the size of the industry by assuming a suitable proportion of work force from the population.
(a) Determine the average per capita consumption of water including the industrial demand and other demands.
(b) No lengthy writing is required for the design problem other than stating all your assumptions
(c) Show all your calculations neatly ( need not be typed)
(d) Summarise your design in a suitable table format and provide justifications for selection of each unit process
(e) Provide a hydraulic profile, schematic and layout of the site of your treatment plant, clearly labelling each component of the process.
(f) Convince the City Engineer that your design is the best that will provide safe uninterrupted water supply at affordable costs to its customers for the next 25 years through a one page summary assuming that the summary is going to appear in the local newspaper.