Help with flout design for dosing to PCDI

if your dosing to pressure compensating drippers, you will need at least 10m head at the drippers, so you need to take into account headloss in the delivery line from the flout to the manifold.

I found a guideline document produced by "Rissey plastic" (who I believe may have invented the flout) on basic flout design and this recommends a 3" min size line from flout to manifold to ensure the line remains fully charged under drawdown.

For LPED dosing I always ensure the dose volume is at least 2x the in-system volume of the delivery line+ manifold + drip lines to ensure the system can fully charge. For a PCDI system dosed by flout I'd probably increase that as once the head drops below 10m the emmitters flowrate will also reduce.

Simon

assume wastewater production is 1200 l/d, I get:

delivery line 55 l
inlet/outlet manifolds 51 l
dripper pipes 51 l
--------------
tot sys vol 157 l

240 dose vol so
-no times sys vol goes into dose vole: 1.5 (ideally want at least 2x)
-no doses/day: 5.0 (preferably >=5)

total flowrate: 20.4 l/min
pump run time: 11.7 min
total daily pump run time: 59 min

NB the Alpha conc precast flout chamber has a dose vol of 400l.

Think Devan plastics also do a flout chamber of similar vol

if use 400 l dose vol:
-no times sys vol goes into dose vole: 2.6 (better)
-no doses/day: 3.0 (not as good!)

its always hard to balance the no time the dose vol goes into the system vol against the no doses per day, so I usually compromise on doses/day to ensure I have at least 2x in system volume so I know the system is getting fully charged.

Changing your emmitter flowrate does not affect above two calcs, it only affect total flowrate and pump run time (flowrate from 20.4 l/min to 31.1l/min and runtime from 11.7 to 7.7 assuming same spacing).

Logically thinking, the higher the emmitter flowrate, the larger the orifice, so the lesser chance of blockage.

I hadnt noticed that the UNIRAM would operated down to 5m head!

Looks like your on the right track.

NB might be worth talking to the Netafrm NZ rep to confirm the UNIRAM type is the best one to use with effluent as the emmitters are designed for irrigation with clean water