Browse Forums Eco Living Re: Need advice on our rainwater collection and storage syst 2Oct 17, 2012 8:11 pm I would tend to discharge all roofs to tank 1. Each tank would be linked to the next at mid height ( With the outlet turned down by 150mm) This will mean that any heavier than water particles will sink to the bottom of tank 1 and any lighter than water particles will float on the top of tank 2. I'd then put two overflows in the first tank. The lower one which takes water, and sediment from the bottom. And a higher level one that allows the floating particles to float off. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Need advice on our rainwater collection and storage syst 3Oct 17, 2012 9:34 pm jnk40 Intending to connect all 4 tanks via the bottom outlets into one line of BlueLine pipe then off to the Grundfos CMB 3-4 pump housed inside the garage. This way I can draw from any tank and use tanks 1 and 3 for settling. Are you sure that's enough flow and pressure, especially being the only pump, and also don't forget garden watering, as well as losses due to length of pipe. Personally, for my garden, I'm using the CMB5-4, with 1.5" inlet, and 1" outlet; cheaper prices can be had if you look around, as I got the 5-4 for $810 delivered mid this year. The CMB series seems to be nosier than the old CH series (which I also have off another tank). Re: Need advice on our rainwater collection and storage syst 4Oct 17, 2012 10:13 pm Hi jnk40, Good questions and great diagrams. Showing your location on your profile really helps too. I won't have time to answer this in detail until next week as I am exhibiting interstate...but I will. I like bashworth's pointers. A couple of quickies for now. Who told you that you will only need two 100 mm downpipes on the house and plumbed at the diagram's indicated position? RAINHEADS. Compulsory (and a necessity) for wet systems in your area. You are also required to have mosquito proof mesh on the wet pipe's outlet. HEAD LOSS AT HOUSE. This will depend on how the rainheads are plumbed. It is possible to plumb them to the gutter and this would be essential if feasible for your situation. The minimum head required is recognised as 300 mm but flow rates must also be calculated and compared to your roof harvest area and rainfall intensity during storms. The problem with the 'available' head is that the proposed 100 mm wet pipe will be above the height of the tank and you must measure the head from the top of that pipe, not from the tank's inlet. I will look into this next week but I can already see that the best solution would be to run wet into a lower inlet to get more head. That would also allow you to do away with the vertical riser plus you can use a low cost but effective DIY sediment trap. OVERFLOWS. I am currently doing research with another inventor on a new balance/mitigation system that will balance the cleaner water at very high flow rates between tanks prior to water reaching the overflow. The first tank should also have an anaerobic zone vacuum system as bashworth has already suggested. WATERBOY. These are very good and you could even make your own. If tank one was a dedicated settling tank, a Waterboy would be best fitted on a small low plumbed settling line from this tank. I would also have one on the outlet feeding the pump. I am no expert with pumps but I always hear good reports about the Grundfos. The secret is not to have restrictive pipework. Also, never use a 12 mm garden hose. At 20 lpm, a 12 mm hose has 8 times more friction loss than an 18 mm hose. Also, have you thought about having another small but tall tank supplied by a balance line located with the pump? I will also suggest you tank outlet options next week. Do you know how long the proposed dry pipes from the garage will be? Re first flush, will you be using water for gardening etc? 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Need advice on our rainwater collection and storage syst 5Oct 18, 2012 11:17 am Many thanks for the replies and information. bashworth I would tend to discharge all roofs to tank 1. Each tank would be linked to the next at mid height (With the outlet turned down by 150mm) This will mean that any heavier than water particles will sink to the bottom of tank 1 and any lighter than water particles will float on the top of tank 2. PHL Are you sure that's enough flow and pressure, especially being the only pump, and also don't forget garden watering, as well as losses due to length of pipe. SaveH2O Who told you that you will only need two 100 mm downpipes on the house and plumbed at the diagram's indicated position? SaveH2O RAINHEADS. Compulsory (and a necessity) for wet systems in your area. You are also required to have mosquito proof mesh on the wet pipe's outlet. SaveH2O HEAD LOSS AT HOUSE. This will depend on how the rainheads are plumbed. It is possible to plumb them to the gutter and this would be essential if feasible for your situation. The minimum head required is recognised as 300 mm but flow rates must also be calculated and compared to your roof harvest area and rainfall intensity during storms. The problem with the 'available' head is that the proposed 100 mm wet pipe will be above the height of the tank and you must measure the head from the top of that pipe, not from the tank's inlet. I will look into this next week but I can already see that the best solution would be to run wet into a lower inlet to get more head. That would also allow you to do away with the vertical riser plus you can use a low cost but effective DIY sediment trap. Although, would running wet into a lower inlet mean a rigid connection? SaveH2O OVERFLOWS. I am currently doing research with another inventor on a new balance/mitigation system that will balance the cleaner water at very high flow rates between tanks prior to water reaching the overflow. The first tank should also have an anaerobic zone vacuum system as bashworth has already suggested. I've seen the tankvac system, smart idea. SaveH2O WATERBOY. These are very good and you could even make your own. If tank one was a dedicated settling tank, a Waterboy would be best fitted on a small low plumbed settling line from this tank. I would also have one on the outlet feeding the pump. SaveH2O I am no expert with pumps but I always hear good reports about the Grundfos. The secret is not to have restrictive pipework. Also, never use a 12 mm garden hose. At 20 lpm, a 12 mm hose has 8 times more friction loss than an 18 mm hose. Also, have you thought about having another small but tall tank supplied by a balance line located with the pump? Sounds like a smart idea re the tall tank with balance line at the pump. I intended housing the pump in the garage out of the weather. It'd be about a 3 meter run max from the common Blueline joining the tanks across to the pump, but, this would involve two elbows to send it underground 1.5 meters across to the garage and up and through the wall to the pump. Ain't gonna work is it? SaveH2O Do you know how long the proposed dry pipes from the garage will be? SaveH2O Re first flush, will you be using water for gardening etc? Many thanks for your valued help here. John Re: Need advice on our rainwater collection and storage syst 7Oct 18, 2012 4:23 pm jnk40 Many thanks for the replies and information. bashworth I would tend to discharge all roofs to tank 1. Each tank would be linked to the next at mid height (With the outlet turned down by 150mm) This will mean that any heavier than water particles will sink to the bottom of tank 1 and any lighter than water particles will float on the top of tank 2. No flexible fittings instead of just a horizontal pipe into the tank you put a 90 degree elbow bend facing downward and 150mm of pipe. What this means is 1. That when all the tanks are more than 1/2 full you will be taking water from the middle of tank 1 Below the floating particles but above the silt in the bottom. 2. If you are really down on water and have to take water from tank number 1 the water will drop below the outlet.......But when it rains again the water won't start to spill into tank No 2 until after the outlet pipe is submerged so you will always be protected against floating particles. This should cost less than $10 rather than the $100+ for a waterboy and give the same benefit The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Need advice on our rainwater collection and storage syst 8Oct 18, 2012 5:05 pm Thanks bw, understand the principle now but still can't picture it. Bit slow on the uptake here. Try not to fall off the chair laughing but is this what you mean? And, did you mean - "No, flexible fittings instead of just a horizontal pipe..." or "No flexible fittngs. Instead of just a horizontal pipe into the tank you put..." John Re: Need advice on our rainwater collection and storage syst 9Oct 18, 2012 6:31 pm Hi Have a look at the picture at http://www.anewhouse.com.au/wp-content/ ... outlet.jpg (I haven't figured out how to post an image on homeone) Brian The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Need advice on our rainwater collection and storage syst 10Oct 18, 2012 10:36 pm Ah, got it now. Here's the pic from that link for others benefit I post images by uploadng them first to free sites like Photobucket or Imageshack etc. This produces a link for the photo which you then copy and paste between the brackets produced after clicking the 'Img' button in the top menu when posting on homeone. A bit of messing around but does the job. John Re: Need advice on our rainwater collection and storage syst 11Oct 19, 2012 10:22 am Thanks for the hints on drawings and pictures. Just another thought about the diagram in the post above Taking water from the bottom of Tank 1 for gardening and for rural Fire fighting purposes will help remove dirty water from the base of that tank. The water will be fine for gardening as long as you don't need to put in through fine nozzles or drippers in which case you will need a filter. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Need advice on our rainwater collection and storage syst 12Oct 19, 2012 12:01 pm Thanks Brian, top idea. Would it be best to add an additional outlet at the base of tank 1 for this purpose? See gravity fed tap in diagram. John Draft of plumbing so far Re: Need advice on our rainwater collection and storage syst 13Oct 19, 2012 1:40 pm Looks good The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Need advice on our rainwater collection and storage syst 15Oct 24, 2012 2:49 am HOUSE ROOF CATCHMENT AREA, GUTTER SLOPE & TWO DOWNPIPES The minimum slope for an eaves gutter is 1:500 (2 mm per metre). Water flows slowly along a gutter with the minimum slope and having a more adequate slope would naturally require a greater height variance between the gutter's high and low points. Having the 16 m gutters with two downpipes at each end would mean that the gutters high points (that determines the gutter slope) would be in the middle (at the third post) and 8 metres from both downpipes. This requires a minimum 16 mm height difference between the high and low points (the downpipes location) but more than this would be needed in QLD for good drainage. The other thing is that the roof pitch is subject to a multiplier to determine a factored (greater) roof area to allow for more wind driven rain falling on one side of the roof. In other words, your house roof has to be calculated as a greater area than the 235 sq m plan area. This in turn determines the required gutter cross sectional area and downpipe size. Eaves gutters are required to be designed to handle a 1:20 Average Recurrence Interval (ARI) and the Gympie 1:20 ARI is 230 mm hr. The calculations are based on a 5 minute intensity, i.e. an average of 3.83 mm per minute for 5 minutes. If the roof was flat (no multiplier), each of your house gutters would be required to drain a minimum of 450 litres per minute (117.5 sq m of roof X 3.83 mm of rain per minute). Add the multiplier and each downpipe has to be factored to drain more than this, i.e. during wind driven rain, more rain will fall on one side of the roof than the other. This also affects the wet system pipes. For your area's 1:20 ARI of 230 mm/hr, a 100 mm downpipe fitted to a gutter with a cross section area of 8,000 sq mm is not regulated to drain more than about 36 sq m of (factored) roof area. Your straight gutters are a roof drainage best case scenario but you will need more than 2 downpipes 16 metres apart to prevent gutter overflows. EDITED 18/05/2014. Text tidy up. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Need advice on our rainwater collection and storage syst 16Oct 24, 2012 8:36 am AVAILABLE HEAD: I cannot recommend that you have water with the house roof slope factored flow rates diverting through two 100 mm wet system pipes with perhaps less than a 300 mm head to a tank's top inlet with your length of wet system pipe. This is assuming that the roof drainage is properly drained (no gutter overflows) to the horizontal pipes. Sooner or later, you will have a storm that exceeds a 1:20 ARI but the likely available head will struggle with flows less than those generated by a 1:20 ARI. The tanks you have chosen have a good height of flat surface on the bottom wall. There are a few options to safeguard against an insufficient head causing problems during heavy rain and the easiest way is to fit two 50 mm inlet valves about 150 mm above the bottom of tank 4. A 50 mm pipe would branch off each 100 mm wet system pipe and connect to a 50 mm inlet and the two 100 mm wet system pipes would still be fitted with vertical risers to two other tanks, probably tanks 2 & 3. The low restriction inlets will operate with priority flow due to their greater minimum head plus provide low restriction flushing flow paths, ensuring that only clean water is retained in the wet system between rain events. Water will only divert up the vertical risers during times of medium or heavier rainfall and/or when tank 4 is nearly full. It is best to fit a flap valve rather than fixed mosquito proof mesh at the top of the vertical riser. The tank that the garage also diverts to will need a higher overflow capacity TankVac to manage the higher inflow during a storm when the tank is full. The Tankvac overflow system vacuums sediment from across the tank's floor by inducing a syphon. It generates this by restricting the initial discharge of water so that the external overflow pipe is purged of air before it starts operating at high velocity (9 litres per second through an 80 mm DWV overflow pipe). The vacuum break is inside the tank and the vacuum breaks once the top of the overflow pipe inside the tank is exposed, preventing the tank from syphoning dry. TANKS: I always recommend having a settling tank system. The above scenario allows tank 1 to supply the house with decanted water transferred from tanks 2 & 3. Dry system pipes from the garage will need vertical supports and this will be ugly. I would merge the pipes at the garage into a single 100 mm wet system pipe with a vertical riser to eliminate the ugly pipe arches. I would also fit a first flush diverter at the garage and a sediment trap at the base of the vertical riser. Balance lines between the tanks would be fitted 100 mm or so above the bottom of the tank at the valve's lowest point. A device like a Waterboy could be fitted internally to low plumbed balance line outlets between tanks 3 & 4 but the balance lines between 3-2 and 2-1 would not need a Waterboy as the water will be clean but fitting one between tanks 1-2 would provide the very best of the decanted water. The balance lines only need to be LDPE 25 mm poly pipe connecting to 1" valves. I would also fit a DIY sediment trap to both 100 mm horizontal pipe. For a 100 mm DWV pipe, you buy and fit the following... (copied from another thread on this forum) One 100 mm 45 degree plain junction F+F. Fit this with the branch on the underside. Connect one 100 mm 45 degree plain bend M+F to the branch. Connect one 100 - 50 mm level invert taper to the elbow. Connect one 50 - 40 mm level invert taper to the larger taper. Once fitted, you connect the taper to 40 mm DWV pipe. There are then a couple of fitting options for draining the 40 mm pipe and by using the smaller pipe, the water can be regularly part flushed with less wastage. The higher velocity discharge through the small pipe also self cleans that pipe. Most of the debris will simply drop down into the elbow and will substantially reduce the amount of sediment in the tank and greatly improve water quality. There are several ways that the sediment trap can be made from off the shelf parts. Don't use the leaf catcher. EDITED on 18/05/2014. Reason: Explanation tidy up. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Need advice on our rainwater collection and storage syst 17Oct 24, 2012 3:07 pm Following this thread with interest as I am at the same point of making water tank connection decisions. I understand the reasonings behind having a wet system enter the tank at a low point (to reduce the disturbance of the settled crud in the bottom of the tank, aerate the anaerobic zone and to increase the available head) however this means the wet system is fully charged at all times once the water level reaches the inlet height. Granted this makes flushing the system easier as the head in the tank assists with the flushing power. @SaveH20 - Is there an upper limit of tank size before the water pressure exceeds the burst pressure (of joints more likely) of 100mm DWV? I am looking at a single 200KL Rhino tank due to available space and budget restrictions. ie 2x100KL wont fit and are $7000 more than the single 200KL tank. The two issues I have with a low point connected wet system is a) failure of the joints in the 100mm DWV sections. If my 200KL tank is full and the pipe burst or joint failed, I will have 150KL+ worth of flooding! plus the loss of all that precious water. b) the lack of ability to place a first flush device into a fully charged wet system. In my opinion a wet system must have a first flush device fitted just prior to the tank inlet. In times of low/nil flow, the water in underground 100mm components could be very stagnant. However I am unable to envisage how you could do that and still have a fully charged system under tank pressure. Regards RiH Re: Need advice on our rainwater collection and storage syst 18Oct 24, 2012 6:22 pm Awesome, SaveH2O! I'm no buff when it comes to the Australian Standards, but surely it ought to also mention the area the gutters "service"? I mean, 100 square meters fed into 10 meters of gutter is quite different than 12.5 square meters fed into 10 meters of gutter. With that said, I will make a compromise on my own build: I'll have square downpipes to match the house, knowing full well they're not as effective as round downpipes. They'll be big, though - I'm thinking 200x300 mm, so two or three of them should be alright for a total catchment area of 130-140 square meters (the roof is almost flat, angled backwarks, so it will run to the back of the house into a single, integrated (hidden) gutter). Re: Need advice on our rainwater collection and storage syst 19Oct 24, 2012 7:33 pm Crikey, a lot to digest there. It's a steep learning curve for me and is certainly a crash course in rain harvesting. Thanks SaveH20, your time in freely giving advice on here is commendable. I'll do some study on the above and reply again with some questions. One thing I haven't been able to get my head around is using the low inlets in the side of the tank. If the tank is even say half full (12,000 litres) wouldn't the pressure of that volume of water prevent any water entering from the wet system? The other thing I'm wondering about is what type of fitting should be used for a low inlet especially considering the Camel tanks have a corrugated side wall profile. I'll check with Camel but they're don't seem to like discussing anything 'out of the box'. Will also check with them re warranty in regards to cutting holes in the sidewall. John P.S. The house kit company has now agreed to supply 3x 100mm downpipes for each of the two awning gutters. Re: Need advice on our rainwater collection and storage syst 20Oct 24, 2012 10:22 pm Great work there SaveH20 (AKA...). I have read your description of the low tank inlet and sediment trap elsewhere and plan to include it in our current build. I had the same query as Rocks regarding pressure/vulnerability of joints and seals and pipes including risk of damage to the inflow pipe leading to backwards loss of water from the tank. Once you know the basics, the rest is easy. Read my post in the thread linked below. viewtopic.php?p=1919271#p1919271 2 19880 There is a whole lot more to know than just the answers you seek but they are a good start. Overflow outlets have a mosquito proof mesh. These… 3 8656 Grate, thank you! RexChan if thats the reason i could sleep well without thinking about additional cost. But 1st i'll need to read about NRV cleaning/replaing stuff. I… 7 31468 |