Water Environment Federation (WEF) Discussion Forums / WEF Discussion Forums / Collection Systems

RE: concrete sewer repair

Dvant — Mon, 05 May 2008 18:11:31 GMT

Slip-lining works well and sure beats digging, most of the time. I like fold and form over CCIP but that may be because the Fold and Form contractor was better to work with.

Mark

concrete sewer repair

robmen01 — Sat, 03 May 2008 12:37:31 GMT

Could you share your experience with no destructive technologies to repair concrete sewer pipes?

We are looking for options, once replace 30 miles of concrete lines is quite expensive.

I will appreciate your help.

R.Mendez

RE: Detention Basin Liners

Jeff Naumann — Thu, 01 May 2008 15:34:53 GMT

underground storage using 36" storm pipe. it is purely storm water but eventually discharges into a combined sewer system a couple miles down stream (contamination from surcharge would not be an issue). in addition to underground pipe storage, a basin was proposed on top of it with a landfill type waterproof liner. there is a catch basin and two access manholes within the limits of the proposed liner. i guess my question is what kind of problems arise if the liner is not properly constructed to be watertight around the edges and open structures. if additional water seeps in due to poor construction, that additional water through the ground would not be so much an issue or would it? as the basin is deeper than 1.5' we require waterproof liners, but i would like to question that requirement may be overkill as the risk for contamination is low. the risk of debris getting underground is low (it is in an urban residential area).

I guess I'm having a bit of trouble visualizing the exact scheme that is proposed. Why would someone design "storage" within buried piping, and have an open pond for storage of the same water directly above it? Or, am I misunderstanding what is proposed?

In any event, I guess I would expect that any "storm water" would likely have some debris in it, which would eventually need to be removed. Using a plastic liner would make using heavy mechanized equipment infeasible. If substantial sediment needs to be removed, you would want to use heavy equipment Why not just design and build a single pond with whatever liner would be capable of supporting whatever equipment needed for cleaning?

Detention Basin Liners

utoots — Wed, 23 Apr 2008 13:20:49 GMT

A project I am reviewing is proposing a detention basin with additional storage in large pipes underground. The detention basin discharges to storm sewer. What are some of the issues that would need to be addressed regarding how the waterproof liner for the detention basin is constructed? There appears to be two manholes for access and an inlet structure within the basin. How does additional groundwater around the manholes (if construction does not address the watertightness on the surface around the manholes) or at the construction limits of the basin?

RE: Detention Basin Liners

utoots — Fri, 25 Apr 2008 10:24:33 GMT

RE: Detention Basin Liners

Jeff Naumann — Thu, 24 Apr 2008 18:53:48 GMT

Is this only storm water? If so, what is the chance that debris will be a part of the stream? Having an underground basin with significant debris (sand, rocks, plastics, paper, couches, dead animals, etc) will not be a pleasant experience for the crews that have to maintain the system.

I'm confused in your statement about "groundwater, manholes, and construction limits."

RE: Odor control with activated carbon

Jeff Naumann — Thu, 24 Apr 2008 18:48:06 GMT

I am looking to purchase activated carbon to help with some of the odor at several lift stations. Does anyone have a reccomendation on this matter?

Have you determined what the odor substances are? How large are the stations? Are they fairly large? There are possibly other ways to control odors, depending upon what the odors are, such as alkaline scrubbers, chemical addition (iron salts, bioxide, etc.).

Are you sure that AC will be effective?

Odor control with activated carbon

01809325 — Tue, 22 Apr 2008 17:18:33 GMT

I am looking to purchase activated carbon to help with some of the odor at several lift stations. Does anyone have a reccomendation on this matter?

RE: Stormwater Management

Sabir — Tue, 22 Apr 2008 23:32:41 GMT

I think it is the most recomended practice to dispose off pet's waste in most of the storm water management procedures i.e. either to flush it down the toilet and/or put it in the household trash after securely wrapping it.

Be aware of the Animal Control Ordinance that governs pet waste clean up – "...waste left by a dog on any property other than the owner's must be cleaned up by the pet owner. If the law is violated, you could be subject to prosecution."

Stormwater Management

wausau — Tue, 22 Apr 2008 11:10:00 GMT

How do you go about dealing with pet waste in your Stormwater Management Program? Would flushing it through the Sanitary System be of concern to anyone as one option?

RE: Casing for watermain construction vs. sewer replacement

Dvant — Mon, 14 Apr 2008 19:01:45 GMT

If it meets your requirements, sleeving the water line with SDR 35 would be cheap.

Mark

Casing for watermain construction vs. sewer replacement

01811158 — Wed, 02 Apr 2008 11:03:20 GMT

I am reviewing a watermain construction plan showing a 12" casing for proposed water-main crossing under four segments of storm and sanitary sewers. What are the trade-offs (cost and difficulty) between a 12" casing (50' long) and a replacement for four sewer segments? I have no information regarding what the service areas are of existing sewers.

RE: Cellinite BioTabs

Rehtis — Mon, 14 Apr 2008 12:55:00 GMT

Yes, I have heard of Cellinite Biotabs and used it to get rid of odour. However, the company's website is www.biotabs.net, not the aquapuck company listed on the blog. I think they are just a distributor of Cellinite Biotabs or something like that. www.biotabs.net is the original company that developed and patented the product. Works really well!

Cellinite BioTabs

CHelgestad — Fri, 03 Nov 2006 08:16:34 GMT

Hey Group,

Anyone try these Cellinite BioTabs? We have a lift station with a small grease problem. I'm looking for a low cost solution. Liquid citrus based degreaser is just too expensive and only softens up the grease, doesn't keep it suspended (not that I'd really want the problem moved down stream).

Thanks, Chris

RE: Casing for watermain construction vs. sewer replacement

Jeff Naumann — Wed, 02 Apr 2008 15:19:02 GMT

Do you mean that the water main is to be "encased?" If so, it's probably "encased" in concrete, which is used to protect the water main from damage that might incur from a break in the piping that would be above it. Normally, you don't want to install a water service pipe "below" a potential contaminating source, such as a sewer line. Plus, a failure of one of the sewers could cause erosion of the soil around those pipes, which could cause stress to the water main. In other words, it would be considered good engineering practice to encase the water main located below a sewer line (or, several sewer lines). If concrete encasement is not to be used, I would guess that other material, such as an outer pipe casement could be used.

I can't imagine that replacing four other pipes would be cheaper than just installing the encasement around the water main. Also, why would the sewer pipes be "replaced?" I am assuming that they are gravity lines, so that routing them other than where they are would be needlessly complicating the issue.

RE: Terra Cotta Sewer Pipe

TerryF — Tue, 01 Apr 2008 17:15:14 GMT

I would start with the old system knowing that there is going to be some work required. This will mean that charges will have to reflect the need for work. However the old system means that you are not up for a major cash slug up front(depends how you are financing it) but you need to make sure that your old system is valued according to its real condition .

Regards

TerryF

Terra Cotta Sewer Pipe

Perkins — Fri, 28 Mar 2008 17:24:20 GMT

I contract with a small town that is working on forming a sewer district. They are considering buying an existing sewer system that was built in the 70's with a terra cotta collection system. Some of the pipe that I have seen looks almost new, but in other places it is pitting and looks like it's starting to thin. There has also been trouble with roots. It's all above the ground water table and our soil is coarse to fine sand. Is there still useable life in this system, or should we start out new on our own? Thanks

RE: larger to smaller pipe connections, construction of force main costs and design alternatives

Jeff Naumann — Tue, 01 Apr 2008 16:43:29 GMT

The lateral is actually within stadium (which is city-owned) property and no, there is no waste upstream from the stadium. It will be handling domestic waste from several service connections from the stadium. I was not clear with the 15" self-cleansing velocity requirement, I meant they wanted to meet the minimum slope requirement for the 15" (0.15%) versus an 8" (0.4%) so that's how they justified connecting to a smaller sewer. I was just wondering what problems (capacity, larger pipe becoming septic, etc.) can arise from connecting a 15" pipe to an 8" pipe and is this good engineering judgment? Existing service connections upstream from where the lateral leaves the property line, it appears, inhibit the allowance for a steeper slope. Would it be more feasible to run a force-main to meet grade?

As long as the 15" pipe system is designed to flow properly, and not allow the settling of solids, it should be fine. Keep in mind that the stadium is used only intermittently so that continuous (or, near-continuous) flushing is not available. I assume that the 8" pipe is at a higher slope, so that it's capacity is actually more than the 15" pipe under typical conditions of flow.

Another reason to NOT install a pump station is the intermittent nature of the system, which would leave some volume of sewage standing in the wet well in between stadium events. This would lead to settling of solids and odors.

larger to smaller pipe connections, construction of force main costs and design alternatives

01811158 — Mon, 31 Mar 2008 10:32:48 GMT

I am relatively new to collection systems design so bear with me.

I am currently reviewing a utility plan proposing a lateral through a development with existing intermediate sewers connecting to it. As it leaves the property line, the design shows a connection from a 15" PVC to an 8" VCP sewer. They justified using the larger diameter sewer to meet its self-cleansing (2.0 ft/s) requirements for 15" sewer and because of the difficulty to meet slope requirements upstream for smaller pipes. Is this good engineering judgment and what kind of capacity or other types of problems can arise from this? Would it be costly to propose a pump station and use a force main to meet these requirements?

RE: larger to smaller pipe connections, construction of force main costs and design alternatives

01811158 — Tue, 01 Apr 2008 12:52:55 GMT

RE: Terra Cotta Sewer Pipe

Jeff Naumann — Tue, 01 Apr 2008 08:32:05 GMT

How about contacting qualified contractors that are capable of doing either option to get a better idea of comparable costs.

I would think that taking on the existing sewers would be cheaper than installing a whole new system.

RE: larger to smaller pipe connections, construction of force main costs and design alternatives

Jeff Naumann — Tue, 01 Apr 2008 08:27:02 GMT

I am having trouble understanding and visualizing the scenario that you are describing. Are you saying that the proposal is for a 15" collection system in the new development that connects to an existing 8" vcp system? And, is there no waste flow "upstream" of the new development?

At any rate, I would expect that the velocity of flow in the 15" pipe would be slower than for a comparable 8" pipe, given the same slope. So, I can't see how increasing the pipe diameter would increase the "self-cleaning" capability of the system. The 2 ft/second flow velocity is commonly used as a minimum in gravity waste piping in order to keep solids in suspension. The trade-off between a force main/pumping station versus a gravity system would be a double-edged sword in that with a gravity system there is the potential for clogging that would require occasional cleaning, while the force main and pump station obviously would be expensive, and would also require maintenance along with the power coast to operate it. It may also require occasional cleaning.

RE: larger to smaller pipe connections, construction of force main costs and design alternatives

Dvant — Mon, 31 Mar 2008 16:43:12 GMT

No, they just don't want to put in a liftstation.

RE: Terra Cotta Sewer Pipe

Dvant — Fri, 28 Mar 2008 18:50:44 GMT

So what are our choices?

Buy an old system that needs to be sliplined or put in a new sewer system. digging a new system 60-100 dollars a foot, cost of old system plus 30 dollars a foot for every place that needs lining.

RE: Infiltration & Inflow

Kimberly Davis — Thu, 27 Mar 2008 14:38:43 GMT

WEF's website "Science and Technology Resources" has a "Private Property Virtual Library" with a wealth of material on laterals. WERF is also doing some excellent work for its members.

I am especially interested in large non-municipal facilities such as military bases, with onsite pipes possibly over 8", but considered laterals! Great potential for unregulated I/I.

Infiltration & Inflow

01262250 — Thu, 15 Mar 2007 16:50:52 GMT

Private laterals contribute well over 50% to our I & I problem. Does anyone know what communities have agreed to be responsible for repair and replacement of private sewer laterals? For those that are, how do they fund this program?

RE: Infiltration

Jeff Naumann — Tue, 04 Mar 2008 18:22:09 GMT

What is the near term and long term outlook for repairing/replacing manholes, manhole chimneys, collection systems?

What is the preferred method for rebuilding manhole chimneys?

What is the forecast for "infiltration watertight" storm sewers?

I'm not very clear on what you are asking. Are you asking in a "business sense," where you want to know whether there are opportunities for providing this kind of work? Or, are you trying to find out HOW TO do the work?

In any event, deteriorating collection systems need to be repaired at risk of further damage to the point of catastrophic failure. How they are repaired will depend somewhat on what they are made of (concrete, brick, fiberglass, steel, etc.). I would assume that most are concrete or brick, or a combination of the two. The actual collector piping could also be cast iron, ductile iron, clay, or plastic.

Perhaps someone with actual experience can jump in.

Infiltration

johnsonhw — Mon, 03 Mar 2008 13:33:28 GMT

What is the near term and long term outlook for repairing/replacing manholes, manhole chimneys, collection systems?

What is the preferred method for rebuilding manhole chimneys?

What is the forecast for "infiltration watertight" storm sewers?

Info on Camera/Jetter Combo

mfox — Wed, 27 Feb 2008 09:23:21 GMT

Does anyone use a 747-FR2000TV jetter/camera combo and if so could you tell me how you like it? Is it user freindly. Any concerns or challenges with operation. Does the camera feature work pretty well?

RE: odor and corrosion control in sewers

Chad — Sun, 24 Feb 2008 12:03:28 GMT

I am trying to make sure we are not over applying the use bioxide just to make sure that we do not experieince any odors

odor and corrosion control in sewers

01736347 — Mon, 04 Feb 2008 20:49:55 GMT

We have odor control dosing stations at numerous pump stations sites. Does anybody know where the balance is between providing odor control and corrosion in the collection system. I am pondering whether if there is a balance point between dosing for odor and dosing for corrsoion prevention, ie. which one is the limiting condition? Any help would be appreciated. Thanks

RE: Ejector pump station - Carnoustie

George R — Sun, 17 Feb 2008 16:27:29 GMT

Jerry,

Thanks for your sensible advice. I will get in touch with S & L as you suggest.

I did manage to get a simple layout of the Smith & Loveless sewage lift station from the US Patent Office.

Many thanks

George R

Ejector pump station - Carnoustie

George R — Sat, 09 Feb 2008 09:52:09 GMT

I'm looking for any drawings that might exist to help me modify an old Smith and Loveless sewage lift station.

The plan is to change the wet well dry well station to a submersible station to eliminate the need for confined space entry. However, I do not have any record drawings and wondered since there must be many of these around whether anyone has a set of typical drawings.

This pump station is probably around 40-50 years old and has already had the ejectors replaced with dry well submersibles.

The name plate shows it was made under licence by Air Products Ltd who were based in Wrexham Wales.

RE: odor and corrosion control in sewers

D Shulmister — Sun, 17 Feb 2008 11:11:13 GMT

I think if you treat for odor control, you probably have solved most or all of the corrosion potential. H2S converts to sulfuric acid. If there isn't enough H2S to create odors, you have solved the corrosion issue.

RE: Flow Equalization Basin

01679057 — Mon, 11 Feb 2008 17:55:52 GMT

Thanks to all who answered, good points were made such as odor problems,but since this will be a temporary containment area for wet weather flows the majority of this flow i'm going to presume will be just that "rain water".My plan is to use our plant effluent to basically wash everything down the drain so to speak. I believe some type of screen mechanism and sump hole that could be vactored out would also help in odor control,since it is going to be at the existing treatment plant I don't think there will be any more obnoxious odors added that are not already common in the area. Although there is numerous repair measures that can be taken to rehab the collection system, after a SSES was conducted no smoking gun was found its just a little bit here there and everywhere,I/I that is. So with the plan to proceed with a EQ, can somebody give me some insight on how to proceed with the structure ie. a liner concrete or some other new technology? Its looking like about 6to8 MG size ,we do have plenty of area to work with. The ability to keep it "fresh" is a concern also-any ideas on how ie. diffused air from PD blowers? floating aerators like on a lagoon ? air induction pumps? Does any one out there actually have one that they are so proud of they would be willing to show it off ? Thanks for your help!

Flow Equalization Basin

mss — Tue, 24 Apr 2007 17:11:56 GMT

We are looking to construct a 6 to 10 mgd flow equalization basin in order to handle wet weather flows at our plant. We are wanting any information on performance, pros & cons of a flow equalization, issues such as odor, aeration, concrete lined or earthen, etc.

RE: Ejector pump station - Carnoustie

Jerry — Sun, 10 Feb 2008 11:15:31 GMT

I went directly to Smith and Loveless via the internet and they had, suprisingly, an old print that I needed.

RE: odor and corrosion control in sewers

John Sansalone — Sat, 09 Feb 2008 14:07:41 GMT

I don't know if it will address your question about corrosion, but there was a lengthy thread on bioxide a couple of months ago. You may want to check out the other subject areas (e.g., O & M). May find some useful info. and opinions there.

RE: Oil & Grease Programs

01724846 — Thu, 07 Feb 2008 15:32:38 GMT

I have found Cary, NC’s to be one of the best – Surf around this link: http://www.townofcary.org/grease/ - it is very thorough.

Kimberly Davis

Oil & Grease Programs

Wisler — Fri, 24 Aug 2007 09:28:05 GMT

Our County is considering developing a FOG program, and I am trying to get an idea of the staffing needs. If anyone could share details of their FOG program, particularly the number of FTE's and program scope, I would really appreciate it.

I can be reached at dwisler@arlingtonva.us

Dennis Wisler