Dual Stand Pipes In Tanks.

[mellow1]

I'm getting ready to built a Recirculating Aquaculture System. I'm working on the plans, and have visited and talked with Tilapia who has a great set up. I was wondering if any of you, who have built tanks, have used a system where you have 2 Stand Pipes in the tank. One for recirculating the water, the other to flush the heavy effluent out of the system completely, and therefore never letting it get to the filtering system. I have seen documents where they have a Dual Stand Pipe System, but it was a large diameter stand pipe with a smaller one inside of it. Complicated and looked like a lot of trouble to make. I'm thinking of a second Stand Pipe which directly flushes out of the system,leaving the other one to recirculate the water, and take the smaller suspended particles to be dealt with by the filtering system. It seem if this is done, it will greatly ease the load to be filtered, and I would be able to get a much better water quality. I will be building circular tanks.

[IsaanAussie]

I'm getting ready to built a Recirculating Aquaculture System. I'm working on the plans, and have visited and talked with Tilapia who has a great set up. I was wondering if any of you, who have built tanks, have used a system where you have 2 Stand Pipes in the tank. One for recirculating the water, the other to flush the heavy effluent out of the system completely, and therefore never letting it get to the filtering system. I have seen documents where they have a Dual Stand Pipe System, but it was a large diameter stand pipe with a smaller one inside of it. Complicated and looked like a lot of trouble to make. I'm thinking of a second Stand Pipe which directly flushes out of the system,leaving the other one to recirculate the water, and take the smaller suspended particles to be dealt with by the filtering system. It seem if this is done, it will greatly ease the load to be filtered, and I would be able to get a much better water quality. I will be building circular tanks.

Hi Mellow,

Can't help with the stand pipes but suggest a low cost alternate I have used before in a circular tank. It involved using a vertical baffle grease pit in the base of the tank prior to the pump. This caught most of the heavy sediments and was cleaned out by hand. Any sludge on the bottom was sweep into the pit. The water was then pumped onto pads of coconut fibre in a seperate tank to filter more of the large particles. These pads could be lifted out and washed or replaced. In my case a stack of two coco-filters was sufficient to clean the water. This filter was deep enough and large enough to allow fine sediment to settle with the clean water been drawn from behind a final vertical baffle at the far end of this settling tank.

In future I would add a few valves and use the pump to sump out the grease pit to waste to avoid having to remove the cover in the tank base to clean it out so often.

More recently I made up a pebble filter onto which the water from the tank was cascaded. The water was then drawn from the bottom of that box through a set of vertical baffles (up and over, down and under, etc..) and into the pump box. Periodically the pebbles can be removed and cleaned. A drain cock in base of both pebble and baffle boxes allowed muck to be drained out.

[mellow1]

I'm getting ready to built a Recirculating Aquaculture System. I'm working on the plans, and have visited and talked with Tilapia who has a great set up. I was wondering if any of you, who have built tanks, have used a system where you have 2 Stand Pipes in the tank. One for recirculating the water, the other to flush the heavy effluent out of the system completely, and therefore never letting it get to the filtering system. I have seen documents where they have a Dual Stand Pipe System, but it was a large diameter stand pipe with a smaller one inside of it. Complicated and looked like a lot of trouble to make. I'm thinking of a second Stand Pipe which directly flushes out of the system,leaving the other one to recirculate the water, and take the smaller suspended particles to be dealt with by the filtering system. It seem if this is done, it will greatly ease the load to be filtered, and I would be able to get a much better water quality. I will be building circular tanks.

Hi Mellow,

Can't help with the stand pipes but suggest a low cost alternate I have used before in a circular tank. It involved using a vertical baffle grease pit in the base of the tank prior to the pump. This caught most of the heavy sediments and was cleaned out by hand. Any sludge on the bottom was sweep into the pit. The water was then pumped onto pads of coconut fibre in a seperate tank to filter more of the large particles. These pads could be lifted out and washed or replaced. In my case a stack of two coco-filters was sufficient to clean the water. This filter was deep enough and large enough to allow fine sediment to settle with the clean water been drawn from behind a final vertical baffle at the far end of this settling tank.

In future I would add a few valves and use the pump to sump out the grease pit to waste to avoid having to remove the cover in the tank base to clean it out so often.

More recently I made up a pebble filter onto which the water from the tank was cascaded. The water was then drawn from the bottom of that box through a set of vertical baffles (up and over, down and under, etc..) and into the pump box. Periodically the pebbles can be removed and cleaned. A drain cock in base of both pebble and baffle boxes allowed muck to be drained out.

Thanks for your reply IsaanAussie. My system will also have a Settling Tank. I'm just thinking of eliminating as much of the heavy sediments as possible and as quickly as possible by flushing most of them directly out of the system, before they even get into the Settling Tank. Just thinking that it may slow the water swirling in the tank, but don't know. The coconut husk ( or only fiber?) idea sounds great for the suspended particles. I will have a cement ditch which will run from the settling tank to the pumps, which feed the biofilter, I will try out a few of these filters in there. How long do they last? Is the filter made just out of the fibers or is it sections of the of the coconut? I suppose putting them in slotted plastic containers(basket) would make a filter? More info would be great, maybe a couple of pictures.. Always looking to cut down on labor.

They have small inexpensive mud pumps, you could use to clean out your sediment with. You have an interesting set up would be nice to see it. I'm in Isaan also, but have no clue where Wat Phia Rong Wua is.

[IsaanAussie]

The coconut husk ( or only fiber?) idea sounds great for the suspended particles. I will have a cement ditch which will run from the settling tank to the pumps, which feed the biofilter, I will try out a few of these filters in there. How long do they last? Is the filter made just out of the fibers or is it sections of the of the coconut? I suppose putting them in slotted plastic containers(basket) would make a filter? More info would be great, maybe a couple of pictures.. Always looking to cut down on labor.

They have small inexpensive mud pumps, you could use to clean out your sediment with. You have an interesting set up would be nice to see it. I'm in Isaan also, but have no clue where Wat Phia Rong Wua is.

Mellow,

Wat Phia is actually on the southern border of Suphan Buri. We are moving to Sisaket soon.

The coconut filter unit was in Indonesia a few years back now, and the pebble filter was in Nonthaburi. I may have a non-digital picture or two of the latter and will have a look around.

The fibres in the coconut filter were an assortment and they were bundled together with sticks and wire into a mat about two inches thick which was trimmed to fit the tank. I have no idea where my gardener got them from but they lasted for over a year and were lifted out and washed out with a hose periodically.

Here you might try roof thatching panels which you can buy for about 3 baht each. As the material is tied onto a stick of bamboo you could use that to suspend them across the flow. They should give you plenty of surface area to catch suspended solids assuming that the rate of fllow is not too quick.

[mellow1]

^ Really a good idea those coconut fibers, will use them for sure, and give it a try. Plenty of coconuts around here. Good to have pictures from a tried and successfull project. Thanks.

[IsaanAussie]

^ Really a good idea those coconut fibers, will use them for sure, and give it a try. Plenty of coconuts around here. Good to have pictures from a tried and successfull project. Thanks.

Mellow,

A word of caution on impeding the water flow with the coco filter. My thought was, to be effective as a filter the finer the fibres the better (more fibres - more surface area), but the ones we used had some quite large sticks and was open in areas. You have to strike a balance in the density and use fibrous materials to which the proverbial <deleted> will stick as well as the finer stuff that appears more to block the particles.

Isaanaussie

[mellow1]

^ Thanks for the advise. Will select the finer fibers when making filter pads. I am also thinking of making a Vortex filter for water coming out of settling tank. Check out this link:

http://www.koiphen.com/forums/showthread.php?t=51997