SuSanA - Forum Kunena Site Syndication http://forum.susana.org/ Wed, 22 Feb 2017 12:57:13 +0000 Kunena 1.6 http://forum.susana.org/components/com_kunena/template/default/images/icons/rss.png SuSanA - Forum http://forum.susana.org/ en-gb Re: Emptying of sludge - How can we know the consistency of the fecal sludge during the emptying if it can be pumped or not? - by: ddiba http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20516 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20516
In the case of Kampala-Uganda, vacuum truck operators usually have an idea of what sludge consistency to expect in particular areas but what I have seen them do a lot also is to pour water in pits so as to make the sludge more workable before pumping it out.

Regards,
Daniel]]>
Faecal sludge transport (including emptying of pits and septic tanks) Mon, 20 Feb 2017 10:10:48 +0000
Re: Emptying of sludge - How can we know the consistency of the fecal sludge during the emptying if it can be pumped or not? - by: kevintayler http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20509 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20509
First, I would say that, in addition to septic tanks, many leach pits are pumpeable. Experience in Indonesia shows that there is sometimes a need to mix some water with the pit contents before pumping it and it is possible that some hard consolidated sludge remains in the bottom of pits (and septic tanks) that have not been pumped for some time. The research from e Thekwini in South Africa shows that some dry pit latrines contain faecal sludge that cannot be pumped but there are other places in Africa, for instance Dakar, where septage has a high water content and certainly can be pumped.

Perhaps the best way to make a quick initial assessment is to assess what is already happening. Do vacuum tankers operate and if so what does the material that they discharge look like - is it thick or thin? Of course, there is always the possibility that they are only taking the top layer from the sludge in the tank/pit but observation of existing practice and talking to tanker operators and manual emptiers will give an idea of the existing situation]]>
Faecal sludge transport (including emptying of pits and septic tanks) Sun, 19 Feb 2017 20:42:05 +0000
Re: Emptying of sludge - How can we know the consistency of the fecal sludge during the emptying if it can be pumped or not? - by: JKMakowka http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20503 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20503 Faecal sludge transport (including emptying of pits and septic tanks) Sun, 19 Feb 2017 06:23:43 +0000 Re: Emptying of sludge - How can we know the consistency of the fecal sludge during the emptying if it can be pumped or not? - by: goeco http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20500 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20500
In my view would be nice to have input from participants representing innovations taking place in this area... there are a range of these described in this forum, some funded by benefactors who I'm sure would like to see information flow.

cheers
Dean]]>
Faecal sludge transport (including emptying of pits and septic tanks) Sat, 18 Feb 2017 22:08:51 +0000
Re: Emptying of sludge - How can we know the consistency of the fecal sludge during the emptying if it can be pumped or not? - by: JKMakowka http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20499 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20499 For septic tanks there is usually enough liquid to pump the majority of the sludge, but it might require some manual mixing and trying to break up the often consolidated sludge bottom.

Other on-site systems like pit latrines you can rarely pump, except maybe by adding quite a lot of water and mixing before pumping.]]>
Faecal sludge transport (including emptying of pits and septic tanks) Sat, 18 Feb 2017 06:02:05 +0000
Emptying of sludge - How can we know the consistency of the fecal sludge during the emptying if it can be pumped or not? - by: andriamanjakagael http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20482 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/20482-emptying-of-sludge-how-can-we-know-the-consistency-of-the-fecal-sludge-during-the-emptying-if-it-can-be-pumped-or-not#20482 I have a subject which I'd like have your opinion: ''How can we know the consistency of the fecal sludge during the emptying if it can be pumped or not?''
Thanks]]>
Faecal sludge transport (including emptying of pits and septic tanks) Fri, 17 Feb 2017 08:51:35 +0000
Re: Solutions for pit desludging and sludge management in low income urban settlements in Malawi (Mzuzu University) - and policy issues - by: rochelleholm http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/6138-solutions-for-pit-desludging-and-sludge-management-in-low-income-urban-settlements-in-malawi-mzuzu-university-and-policy-issues?limit=12&start=12#20352 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/6138-solutions-for-pit-desludging-and-sludge-management-in-low-income-urban-settlements-in-malawi-mzuzu-university-and-policy-issues?limit=12&start=12#20352
Pit Latrine Fecal Sludge Resistance Using a Dynamic Cone Penetrometer in Low Income Areas in Mzuzu City, Malawi
by: Charles F. C. Chirwa, Ralph P. Hall, Leigh-Anne H. Krometis, Eric A. Vance, Adam Edwards, Ting Guan and Rochelle H. Holm
Int. J. Environ. Res. Public Health 2017, 14(2), 87; doi:10.3390/ijerph14020087

Abstract
Pit latrines can provide improved household sanitation, but without effective and inexpensive emptying options, they are often abandoned once full and may pose a public health threat. Emptying techniques can be difficult, as the sludge contents of each pit latrine are different. The design of effective emptying techniques (e.g., pumps) is limited by a lack of data characterizing typical in situ latrine sludge resistance. This investigation aimed to better understand the community education and technical engineering needs necessary to improve pit latrine management. In low income areas within Mzuzu city, Malawi, 300 pit latrines from three distinct areas were assessed using a dynamic cone penetrometer to quantify fecal sludge strength, and household members were surveyed to determine their knowledge of desludging procedures and practices likely to impact fecal sludge characteristics. The results demonstrate that there is a significant difference in sludge strength between lined and unlined pits within a defined area, though sludge hardened with depth, regardless of the pit type or region. There was only limited association between cone penetration depth and household survey data. To promote the adoption of pit emptying, it is recommended that households be provided with information that supports pit emptying, such as latrine construction designs, local pit emptying options, and cost. This study indicates that the use of a penetrometer test in the field prior to pit latrine emptying may facilitate the selection of appropriate pit emptying technology.

To help you access the full article which is open access, please visit www.mdpi.com/1660-4601/14/2/87 .]]>
Faecal sludge transport (including emptying of pits and septic tanks) Sun, 05 Feb 2017 10:01:40 +0000
Re: Time taken for faecal sludge tankers to discharge? - by: kevintayler http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20199 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20199
Thanks for this. I am currently in Dehradun, India and had a chance to observe a tanker discharging into a sewer on Friday. The tanker capacity was 4000 litres and the outlet was 100mm but they connected a 75m hose to the outlet and dropped the hose into the sewer. That would have increased the head at the end of the pipe but on the other hand there would have been friction in the pipe. The tanker took about 3 minutes and 30 seconds to empty the tanker (assuming it was full which may not have been the case). That equates to about 20 litres per second which is in line with theoretical calculations using orifice theory (albeit ignoring the effect of the hose). The Brazilian experience, along with many of the others referred to in this thread, is that discharge rates are less than this. I think that the overall conclusion is that, whatever the theory says, there is no substitute for recording actual discharge rates - thicker sludges may well take longer to discharge.

One point Christoph is that you do not mention the size of the outlet, I would guess 100mm but it would be good to confirm

Regards to all
Kevin]]>
Faecal sludge transport (including emptying of pits and septic tanks) Mon, 23 Jan 2017 03:52:50 +0000
Re: Vacuum truck, vacuum tanker - what is it? Simple definition for lay people reading on Wikipedia? - by: JKMakowka http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/19578-vacuum-truck-vacuum-tanker-what-is-it-simple-definition-for-lay-people-reading-on-wikipedia#20197 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/19578-vacuum-truck-vacuum-tanker-what-is-it-simple-definition-for-lay-people-reading-on-wikipedia#20197 christoph wrote:

“There are two different ways to mount the pump: either directly on the truck with the vacuum drive powered by the truck motor, or on the trailer with an independent motor. The more complicated trailer mounted version allows the utilisation of both the negative pressure suction side of the pump as well as the positive pressure side to pump sludge over longer distances or lift it higher into the tank.”

The observation is not correct. It is possible to pressure the suction side of the pump as well when powered with the truck motor. Actually I hardly know Vaccum tanker with a pump on a trailer I would say that is less than 5% of the cases.


Yes it is quite uncommon, as with a air vacuum pump it is difficult to build a setup that can also push. Of course technically you can have the same on the truck (for quicker emptying for example), but that wouldn't really increase the possible lift more than maybe a meter difference between the motor and the top of the tank, no? So practically speaking the text in the wiki (which I wrote) is correct, as the point of having it on a trailer would be to move the pump closer to the septic-tank and thus reduce the length and hight-difference of the suction hose. Or am I misunderstanding what you meant?

christoph wrote:

“Due to the inherent suction limitations of all suction pumps, that can only lift a liquid through atmospheric pressure, a theoretical maximum water lift of approximately 10.3 m (33.9 feet) can be reached.[4]“

That is not correct. It should be.

The typical maximum lift depends on the equipment (vaccum pump) and the material to be transported. The mixture of water/sludge and air (to be controlled by the operator) reduces the density of water/sludge and a theoretical water lift above the clean water lift limit is possible. In practical operation lift differences of over 15 m will seldom be possible. This limits as well the length of the hose. Only in limited cases a hose larger than 50 m will be used.


Can you explain that a bit better? Am I guessing right that the higher density of the sludge solids is not so significant, so that by adding air into the mix the overall density of the sludge/air mix can be brought down significantly below that of pure water?
I always thought adding air was only a way of offset other losses, not actually to increase the overall lift above the theoretical limit of water.
Edit: I changed the text a bit to explain this better. However I also don't have a good source for this.]]>
Faecal sludge transport (including emptying of pits and septic tanks) Sun, 22 Jan 2017 21:33:50 +0000
Re: Vacuum truck, vacuum tanker - what is it? Simple definition for lay people reading on Wikipedia? - by: christoph http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/19578-vacuum-truck-vacuum-tanker-what-is-it-simple-definition-for-lay-people-reading-on-wikipedia#20196 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/19578-vacuum-truck-vacuum-tanker-what-is-it-simple-definition-for-lay-people-reading-on-wikipedia#20196 I don´t have the references on hand, therefore I did not change anything in Wikipedia. I try to put some aspects here from the page so that you can use or discard them without changing Wikipedia

General

A vacuum truck or vacuum tanker is a type of tank truck that has a vaccum pump and a vaccum tank, designed to pneumatically succion liquids, sludges (such as fecal sludge) or slurries or sand/water mixture without the contact of any mechanical equipment. They are mainly used to transport sanitary waste (human excreta mixed with water, e.g. from on-site septic tanks) as well as for some industrial liquids or slurries and equipped with a high pressure pump they are used to clean out sewers from sand.
The material has to be transported to a treatment or disposal site.

In the text

Pumps:
“There are two different ways to mount the pump: either directly on the truck with the vacuum drive powered by the truck motor, or on the trailer with an independent motor. The more complicated trailer mounted version allows the utilisation of both the negative pressure suction side of the pump as well as the positive pressure side to pump sludge over longer distances or lift it higher into the tank.”

The observation is not correct. It is possible to pressure the suction side of the pump as well when powered with the truck motor. Actually I hardly know Vaccum tanker with a pump on a trailer I would say that is less than 5% of the cases.

Suction lines… Better .. suction hoses?

“Due to the inherent suction limitations of all suction pumps, that can only lift a liquid through atmospheric pressure, a theoretical maximum water lift of approximately 10.3 m (33.9 feet) can be reached.[4]“

That is not correct. It should be.

The typical maximum lift depends on the equipment (vaccum pump) and the material to be transported. The mixture of water/sludge and air (to be controlled by the operator) reduces the density of water/sludge and a theoretical water lift above the clean water lift limit is possible. In practical operation lift differences of over 15 m will seldom be possible. This limits as well the length of the hose. Only in limited cases a hose larger than 50 m will be used.

I hope that helps a bit.
Regards
Christoph]]>
Faecal sludge transport (including emptying of pits and septic tanks) Sun, 22 Jan 2017 17:17:46 +0000
Re: Time taken for faecal sludge tankers to discharge? - by: christoph http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20194 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20194 just some quick comments.
Background: We (Rotária do Brasil) operate 3 tankers and we are part of an association for sludge emptying with 26 tankers in southern Brazil. We operate at one treatment plant.

• The regular discharge time for a tanker of 8 – 9 m³ is about 15 min.. quite similar to the practical numbers mentioned here.

• What is “pressure out”? Normally a tanker empties by gravity, that is better for the equipment and uses less gas. If needed there is the possibility to pressure up the vaccum tank in order to “pressure out” the liquid quicker or if you have to empty against a small difference in level. But that procedure is not very well accepted as it is “stressfull” for the equipment, so it is done only in special situations.

Hope that complements the picture.

Regards
Christoph]]>
Faecal sludge transport (including emptying of pits and septic tanks) Sun, 22 Jan 2017 15:50:38 +0000
Re: Time taken for faecal sludge tankers to discharge? - by: Reetu http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20152 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20152
Just wanted to add, unloading was made by the gravity flow as there is no control valve at the outlet.

Kind regards
Reetu]]>
Faecal sludge transport (including emptying of pits and septic tanks) Wed, 18 Jan 2017 09:31:59 +0000
Re: Vacuum truck, vacuum tanker - what is it? Simple definition for lay people? - by: JKMakowka http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/19578-vacuum-truck-vacuum-tanker-what-is-it-simple-definition-for-lay-people-reading-on-wikipedia#20151 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/19578-vacuum-truck-vacuum-tanker-what-is-it-simple-definition-for-lay-people-reading-on-wikipedia#20151 muench wrote:

Could you please help me by telling me what I should write there for:
  • Maybe a sentence on the maximum typical lift (and related maximum length of suction hose) could be included as that seems to be a practical question that comes up now and then?
  • The pump capability (height and distance limits) would certainly be good information to include



I made some small additions and changes to the article, however I came to realize that explaining the above in the detail necessary (type of pump, strength of vacuum, type & size of suction hoses used etc.) would probably be outside of the scope of this article.]]>
Faecal sludge transport (including emptying of pits and septic tanks) Wed, 18 Jan 2017 09:14:14 +0000
Re: Time taken for faecal sludge tankers to discharge? - by: kevintayler http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20150 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20150
Your information is useful. It confirms what has become clear from other people's information that it takes longer to discharge than suggested by theoretical calculations based on orifice theory. This may be partly due to the point already made by Shaji that the operators do not always open the valve fully to avoid splashing. I think it means that I will remove the theoretical graph from the book, give some typical discharge times based on information received from you and other people and emphasise the need to design inlet facilities using recorded discharge times

Thanks again
Kevin]]>
Faecal sludge transport (including emptying of pits and septic tanks) Wed, 18 Jan 2017 07:13:46 +0000
Re: Time taken for faecal sludge tankers to discharge? - by: Reetu http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20149 http://forum.susana.org/component/kunena/99-faecal-sludge-transport-including-emptying-of-pits-and-septic-tanks/18932-time-taken-for-faecal-sludge-tankers-to-discharge?limit=12&start=24#20149 This is late now but just wanted to share unloading time in context of Nepal.
We, Environment and Public Heath Organization (ENPHO), had done questionnaire survey with the sludge emptier of Kathamndu valley, capital city of Nepal, and also recorded the time of unloading by ourselves. According to them and from our experience, it takes 7 to 10 minutes to unload 4000 liters of fecal sludge(FS)from 6 inches diameter outlet hose depending upon the proportion of solid and liquid matter in it.

Looking forward for your publication.

Reetu]]>
Faecal sludge transport (including emptying of pits and septic tanks) Wed, 18 Jan 2017 04:33:58 +0000