Design of Water Treatment Plant

Explore physical pollutants in water, focusing on suspended solids, turbidity, color, taste and odor, temperature, and conductivity, and explain their sources, impacts, and measurement in water treatment.

Investigate chemical pollutants in water, including total dissolved solids, dissolved inorganic and organic substances, metals, pH and alkalinity, and how they affect taste, color, odor, and corrosion.

Identify biological pollutants in water, including pathogens such as bacteria, viruses, protozoa, helminths, and algae, and use coliform indicators like total coliform, fecal coliform, and E. coli to test contamination.

Explain groundwater and surface water treatment processes, including aeration, softening, filtration, disinfection, and storage, and show how backwash, sludge disposal, and residual disinfection support a safe distribution system.

Explore water treatment plant design, including pre-sedimentation, primary clarifier, coagulation and flocculation with a flocculator, secondary clarifier, filtration, disinfection, storage, and settling tank types.

Explain the theory of sedimentation by analyzing horizontal and vertical velocities, maintaining low horizontal velocity with weirs, and calculating the overflow rate and retention time for settling tanks.

Outline the design criteria for settling tanks, including depth and detention time ranges for discrete and flocculating particles, and overflow, velocity, and weir limits.

Design a long rectangular primary settling tank for a 15,000 m3 per day plant using an overflow rate of 30 m per day, with two tanks and weir arrangements.

Design a circular sedimentation tank for discrete particles with a 25 m diameter, 2.8 m settling depth, 1374 m^3 volume, yielding 2.2 h retention time and 5.94 weir overflow rate.

Design a long rectangular settling tank for flocculating particles using two tanks with a 3:1 length to width ratio, width 11.2 m and length 34 m, depth 3.5 m.

Evaluate the design of circular settling tanks for flocculating particles, including two-tank configuration, settling zone volume, retention time, inlet/outlet considerations, and weir overflow rate.

Design a 50,000 m3/day water treatment plant focusing on primary sedimentation, with five rectangular tanks, each 12 m wide, 36 m long, and 3 m deep (1296 m3 per tank).

Design uses long rectangular primary sedimentation tanks with L/W equals 3 and L/h equals 12 to achieve a 3.11 h retention time. Three additional weirs ensure overflow criteria are met.

Design circular primary sedimentation tanks to meet retention-time and flow targets, selecting three tanks with a 30 m diameter and four-meter total depth.

The coagulation tank lecture covers rapid mixing with back-mix or flat blade impellers, emphasizing mixing time and velocity gradient, detention time, and H/D range using alum.

Design coagulation tank 2 with two back-mix impeller tanks, 17.36 m³/min, 1 min retention, 3 m depth, diameter 2.7–3 m, and 25 mg/L alum dosage.

Designs a three-basin flocculation tank with slow mixing to protect flocs, decreasing G values across compartments, and optimizing detention time for effective coagulation.

Calculates power requirements for a three-compartment flocculation tank by applying G values, viscosity, and paddle geometry to derive per-compartment power and paddle width.

Compute paddle rotational speeds across three flocculation tank compartments, deriving paddle velocity, power, and actual speed, and set the first compartment at the highest rpm to prevent floc breakage.

Design a secondary settling tank by evaluating long rectangular and circular options with a five-hour retention time and 50,000 m3/d flow to determine volume, surface area, and tank counts.

Design a long rectangular secondary settling tank, verify l/w and l/h ratios, retention time, and weir overflow rate; plan seven tanks with inlet and outlet zones.

Design of secondary settling tanks evaluates circular tanks from one to five units to meet five-hour retention, yielding five tanks with 27.5 m diameter and 3.5 m depth.

Designs rapid sand filtration tanks for a water treatment plant, detailing a sand and gravel filter bed, backwash cycles, and valve operations to maintain effluent quality.

Design underdrain system beneath the filter by calculating laterals, manifolds, perforations, and lengths to optimize bed layout and water flow.

Design a multi-bed filter with 1 m media depth (60 cm sand, 40 cm gravel) and 0.5 mm sand (U = 1.6); plan backwashing 30 minutes at 14 m head.

Explore chlorine-based disinfection and storage tank design for a 50,000 m3/d water plant, covering HOCl/OCl- chemistry, residuals, dosing, detention time, tank dimensions, and baffle mixing.