Lecture 3 EU2: Potable Water Storage

Potable Water Storage

• _____

• _____

• _____

• Underground Water Reservoir

• Water Tank - ground level

• Elevated Water tank

Underground Water Reservoir

• mostly rectangular prism shape

• Has an inflow and outflow

• Sump Pit - makes pumping water out the reservoir easier

  • if may maintenance iddrain yung

    water para linisan.

  • After lagay sa sump pit,

    tsaka lalagyan ng submersible pump para

    maubos yung tubig

• Pataas - mababa pressure (upper part yung inflow)

• Pababa - mataas pressure (Lower part yung outflow)

• May sensor para hindi magoverflow, matic

  magsasara yung valve

Ground Level Water Tank

• Cylinder shaped.

• Mas madaling linisin compared sa ibang potable water storage

• Ginagamit si cylinder type, like sa Clark

  Water, sa Prime Water sa Orani, sa

  Waltermart sa Balanga

• Inflow sa taas fini-fill up. May sensor uli to

  avoid overflow

• Outflow, sa baba pa rin kasi triangular pa rin

  yung presure

• Sump pit uli sa baba, may slope

• Madalang yung general cleaning ng mga

  water tank kasi matagal yung process. 6hr

  disinfection, 24 hours waiting. If ganon

  katagal mawawalan ng service, malaki

  mawawalang money.

Elevated Water Tank

• Cylinder shaped though may legs.

• Sa Bakal gawa, back then concrete is the leading material

• Pressure Diagram is Triangular pa rin

Why use Water Tanks/Reservoir?

• _____

• _____

• _____

• _____

• lessen operation cost in pumps

• pressure maintenance The Larger the tank, the more stable pressure to the system

• Emergency storage during power outage, unexpected shutdowns

• Lessen energy consumption (peak energy usage)

Underground Reservoir - Pros

• Least susceptible to temperature

• Aesthetics

Underground Reservoir - Cons

• Land Availability

• Construction Duration

Ground Level Tank - Pros

• Seismic Considerations

• Easy to Construct

• Cheapest out of the three potable water storage

Ground Level Tank - Cons

• Aesthetics

• susceptible to temperature

Elevated Water Tank - Pros

• Land Availability

• Can construct at any terrain

Elevated Water Tank - Cons

• Expensive

• Aesthetic

• Susceptible to Temperature

Water Quality Problems

• _____

• _____

• _____

• Chemical Problems

• Microbiological Problems

• Physical Problems

Loss Of Disinfectant Residual

• The Loss of Dissinfectant residual is a chemical process resulting in the decrease of the secondary disinfectant generally either free chlorine or total chlorine

• It is probably the most common water-quality concern and is a function of time and rate of disinfectant decay (loss)

• The rate of loss can be affected by

  • microbiological activity,

  • temperature,

  • nitrification

  • exposure to ultraviolet light (sun)

  • amount and type of disinfectant demanding compounds present such as organic and inorganic compounds/

Chemical Problems

Formation of Disinfection by Products (DBP)

• Disinfection by-products (DBP) are formed when the disinfectant used reacts chemically with the organic material in the treated water.

Chemical Problems

Development of Taete and Odor

• Happens particularly on new water tanks

• The Sources of tastes and odors in the distribution system, including emission from construction materials, external contaminants, biological activity, disinfectant residuals, and DBP

Chemical Problems

Microbiological Problems

Bacterial Regrowth

• Bacterial and regrowth and biofilms are typically more of a problem in piping systems in a storage facilities because of the greater surface-area-to water volume ratio when compared to storage facilities.

Worms and Insect

• It is possible for worms or insects to enter the distribution system through finished water-storage facilities, cross connection, dead-ends, or from stirred-up sediment in the bottom of distribution mains

Microbiological Problems

Sediment Build up

• Particulates may be introduced in the distribution system if the water treatment facility is not working properly.

• Sediment frequently accumulates in the storage tanks where the velocities are minimal

Physical Problems

Entry of Contaminants

• Open reservoirs or storage facilities potentially are subject to contamination from bird droppings and other animal extrement that have the potential to transmit the disease-causing organisms to the finished water.

Physical Problems