Spray Distribution Systems

1
Spray Distribution Systems

• Bruce J. Lesikar
• Texas Cooperative Extension

2
Spray Distribution Systems

• Four main components
• Wastewater treatment system
• Disinfection system
• Pump tank
• Spray Heads

3
Spray Distribution System
4
Spray Distribution
5
Wastewater Treatment

• An advanced process that purifies wastewater by
  removing solids and organic matter.
• Secondary quality effluent is required for
  surface application

6
Water Quality

• BOD TSS (30 day average) ? 20 mg/l
• 7 day average ? 30
  mg/l
• Daily Maximum ? 45 mg/l
• Single Grab ? 65
  mg/l
• PH
  ? 6.0-9.0

7
Water Quality, CBOD (1996)

• 30 day average ? 15 mg/l
• 7 day average ? 25
  mg/l
• Daily Maximum ? 40 mg/l
• Single Grab ? 60
  mg/l
• PH ?
  6.0-9.0

8
Spray Heads

• Impact spray heads placed in the landscape to
  distribute the water uniformly on the ground
  surface.
• Can have some of the heads providing an
  overlapping area to cover a square area. Cannot
  double count the overlapped area.
• Less than 40 psi pressure
• Low angle nozzles (15 degree trajectory or less)

9
Disinfection system

• Removes pathogens (disease-causing organisms)
  from the wastewater.
• Chlorination is the most common Disinfection
  method.
• Ultraviolet light and ozone are two additional
  methods.

10
Tablet Chlorination

• Tablet chlorinators generally have four
  components
• Chlorine Tablets.
• A tube that holds the tablets.
• A contact device, which puts the chlorine tablets
  into contact with the wastewater.
• A storage reservoir, usually a pump tank where
  the water is stored before it is distributed.

11
Tablet Chlorination System
12
Tablet Chlorinator
13
Bottom Tablets Dissolving
14
Removing Old Tablets
15
Pump Tank / Spray System
16
Spray Distribution Pump Tank

• Night Dosing Systems distribute water between
  midnight and 500 am
• Night Dosing Systems - minimum dosing volume of
  one day flow
• Alarm volume of 1/3 daily flow for a system with
  less than 1000 gallons of daily flow
• On-demand systems minimum dosing volume of ½
  daily flow.

17
Spray Separation Distances

• Property Lines - 20 feet from property for
  on-demand systems, 10 feet for night spray.
• Clear area around spray head 10 feet in the
  direction of spray from the head.
• No vertical separation for groundwater and
  restrictive horizons

18
Spray Distribution Maintenance Testing

• Every four months.
• Commercial sites (one BOD5 and TSS Grab Sample
  per year). Not exceed 65 mg/l for single grab.
• Pathogens Total Chlorine residual 0.1 mg/l,
  Fecal coliforms 200 MPN/100 ml or 200 CFU /100 ml

19
OM Spray Dispersal System

• Check pumps and controls within the tanks at
  least every six months.
• Respond to alarms signaled on a system.
• Response time depends on system reserve volume
  above the alarm-on level and simplex or duplex
  system.
• Maintain vegetation on the dispersal field,
  mowing will control vegetative growth.
• Walk the fields to check for ponded effluent.
• Repair broken lines and irrigation heads
• Clean in-line pump filters and field screens
• Pump the dosing tank when solids accumulate in
  the bottom of the tank.

20
Color Coding Standard

• Reclaimed water standard Purple Color
• All new distribution piping - Piping, Fittings,
  Spray Head Tops, Valve Box Covers
• Effective Date June 13, 2002

21
Full Utilization of Space
22
Separation Distances
23
Spray Head Protection
24
Spray Head Distribution