MINUTES SAFETY/SERVICE STANDBY COMMITTEE -
[Cached Version]
Published on: 12/17/2002
Last Visited: 1/7/2003
Others attending: Council Members Gershman, Christensen; Todd Feland, director of Public Works, Candi Stjern, Al Grasser, Mark Walker, Beecher Vaillancourt, Steve Burian (AE sub consultant to Black & Veatch), and Scott Carr, Black & Veatch.
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Scott Carr, Black & Veatch, reviewed their draft report on biosolids management plan prepared for the City of Grand Forks.
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Mr. Carr stated the definitions of sludge which is by-product from the wastewater treatment process and biosolids is sludge that has been treated to where they can be beneficially used as a fertilizer or soil amendment.He stated they noticed is the component of sludge that is generated as a result of flows and loads from industries (RDO and Simplot) actually comprise about 75% of the sludge that is going to be generated at the future facility.He stated that RDO and Simplot each have their own wastewater treatment process (much like the City's) and as part of those processes they generate sludge, and the sludge comes through the sewer to the wastewater treatment plant; they then asked does it make sense to take the sludge from the industrial plants and handle that separately, not total wastewater discharge because for Simplot the sludge comes back, RDO has some additional treatment on it so not creating as much sludge, but there's a potential for actually handling those sludges at the industrial plants and the advantage of that is that industrial sludges has no domestic or no human wastewater component in it, all food wastewater product and does not require as much treatment to be of beneficial use, and looked at it over a 20-year period at two options (one option being separating it out and providing facilities at the industries for handling those sludges separately and over a 20-year period looking at a savings of roughly 9 million to
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handle those separately.The other advantages without that sludge coming through the plant would be a little bit easier for wastewater treatment superintendent to manage the wastewater treatment process.He stated their next step was to establish the alternatives they were going to evaluate - 5 alternatives and each one had a separate component where the industrial sludges were being handled at the industries providing facilities at the industries and the industries providing the manpower and those costs were included in all the alternatives.He stated their goal was to identify the 5 best options that would meet the City's long term needs.
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Mr. Carr stated it would be basically serve as a nitrogen fertilizer material and probably 5% nitrogen content that would be primary value to farmers and would be looking at row crops (corn, beans, etc.), that AE looked at the region and the land characteristics, looking at more than 10 miles out from the plant to find suitable land, there is a relatively high water table close into the plant that would cause problems for laying application but once get beyond that there is quite a bit of acreage available for it and would be working with the local farmers to arrange time periods for laying application.He stated that nationwide that is probably predominant method - about 40% of material is land applied with Class B type material.Another large portion of material is used thermal drying dry product used as a fertilizer also.He stated the City would have to meet under federal regulations that regulate metals and City shouldn't have a problem with that and stabilize for the package control - it has been treated to reduce the containments to a suitable level.
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Mr. Carr stated the city would have to track the Class B products where it goes and how much has been applied on the site and EPA requires reasonable
level of monitoring and record keeping; with Class A treatment that product you could use in
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your home garden, front yard.Kerian asked if Class B material could be used as cover in the landfill; Mr. Carr stated they talked to the State initially about that because their under-standing is that you need some soil augmentation at the landfill and thought it might be great to blend in with the soil out there to further extend its use but feedback from the State is No - they would not allow that because its not considered an inert material because there's still some bulk and solids, that they went out about a month ago and talked to the State about this program and the same people were there and were very receptive and the manager of the solid waste program stated we don't have enough dirt and need augmentation and were willing to work with the City and do some trials and it may be a possibility.
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Mr. Carr stated with thermal drying, not lose much nitrogen with that, but com-posting does, but quite a few utilities charge for the heat dry product but receive benefit for Class B product. (some places charge nominal rate and charge transportation of material and wanted to establish a value for it because it is a valuable product).
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Mr. Carr and Mr. Burian also reviewed updated treatment option, ramifications if lagoons are closed and next steps.
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Mr. Carr stated what are the implications if don't do all the facilities at the industries but if let that come through, the tanks the effluent from the plants as well as the sludge, and have selected Alt.2 and with that they are taking one tank out of production so out of the wastewater treatment process - look at baseloading the wastewater treatment plant at some flow, current flow averaging somewhere between 7 and 8 mgd and the plant designed for an average of 10mgd with a peak up to 35mgd and said look at baseloading the plant at some 10 minus x and bypass everything above that to the lagoons and take advantage of that existing treatment pass to the lagoons -
Mr. Carr stated the main issue with EPA is this sludge going to the lagoons, when they first talked with the State they seemed to buy off on this concept, the issue here is when send sludge to the lagoons is this microbubble flotation sludge, no digestion, is going to one of the big primary ponds for 3 years and if you keep doing that, EPA classifies that at a surface disposal site (sludge monofield, landfill) and requires extensive site monitoring and City has deter-
mined that you don't want to have to pay a surface disposal site.In this concept the sludge would be going to the lagoons with the effluent wastewater so won't be separate and some benefit with the sludge going to the lagoons for further treatment of that effluent - this is where EPA and the State have permit compliance, certain limits you have to meet and this concept will meet your permit requirements.
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Mr. Carr stated another option would be that there are a lot of contractors out there and that's their business and they go out and dredge lagoons and could dewater the material and deliver it to an air-drying pad where could be air dried to be used.
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Kerian asked if there was a difference in where industrial and where residential - Mr. Carr stated it will be as it is right now, and rather than going through lagoons will come through the new wastewater plant, only difference is that taking one of the basin and using it as a digester and peak flow, going to bypass and there would be no separation of the industrial versus the domestic, no way to do that short of putting in new pipelines from the industries and not looking at that.
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Mr. Carr stated it is all coming into the sewer, whether human or industrial wastewater, through the wastewater plant, and the activated sludge it is generating is under federal regulation and is wastewater sludge and has a domestic component to it and has to be managed under federal regulations - 503 is the number of the regulation.
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Mr. Carr stated they met with the State Health Department a month ago and presented the concept to them, they were very supportive of it; since then just made a phone call with them and EPA and EPA was very supportive of it and indicated that at least until they saw something and not commit to anything until they have it in writing in front of them - and over the phone stated sounds like no problems taking the sludge and the effluent to the lagoons and wouldn't classify those as surface disposal facilities down the road, they may not even require dredging.
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Mr.Carr stated in their memo going to have to stipulate and lot depends on how the plant performs, modeling it based on no operations data.
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Mr. Carr stated what the next steps are - going to do further evaluation for this memo to help document that concept, following that once everybody approves the City and initiates design for the dewatering facilities so that three-year period window and meet that requirement and monitoring the wastewater treatment plant as operations start up - and as the City starts thinking down the road and start looking at CIP requirements and start looking at disinfection facilities as well as outfall requirements and that's long range plan of action.He stated that concludes their presentation and have included in the back schematics of the additional alternatives they are evaluating.
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