071472-20090218-Appendix-L-XCG-Report-July-21-2008

3-1358-04-02/M_3-07087419 Sudbury WWTP Class EA VF 01/14/09

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DATE: July 21, 2008 XCG FILE NO.3-1358-04-02

TO: Dennis Consulting

CC:

FROM: Susan Hansler

RE: Conceptual Level Design for MBBR Option

1. INTRODUCTION The Moving Bed Biological Reactor (MBBR) option for the expanded Sudbury WWTP is being reviewed to determine if nitrification can be accommodated at the plant (spatially) in conjunction with a biosolids facility, if required. The objective of this memorandum is to prepare a conceptual level design for the MBBR option for the expanded Sudbury WWTP. This evaluation was based on a future average day flow (ADF) of 102, 375 m3/d, and a peak flow through secondary treatment of 204,750 m3/d, as per the October 1992 ESR prepared by Dennis Consultants Limited.

As part of the Class EA process, several feasible secondary treatment options for the expanded Sudbury WWTP will be evaluated, including the MBBR option. The preferred secondary treatment process will be selected based on the evaluation and documented in the ESR.

2. MOVING BED BIOLOGICAL REACTOR (MBBR) The MBBR process consists of an aeration basin filled with suspended media and a secondary clarifier. The process, which is patented by Kaldnes, is based on the biofilm principle, and combines the advantages of the suspended growth and fixed film systems.

The core of the process is the suspended media, or biofilm carrier elements, which are made of polyethylene with a density slightly below that of water. The elements are designed to provide a large protected surface area for biofilm growth. This process allows for operation at a higher biomass inventory per m3 of reactor volume than would be achievable with a conventional activated sludge process (ASP), without additional solids loading on the secondary clarifiers. This results in a reduction in the footprint size of the facility relative to a conventional ASP system.

Up to 67 percent of the reactor volume can be filled with bulk carrier elements, corresponding to an effective biofilm area per unit of aeration tank volume of up to 333 m2/m3. Only approximately 10 percent of the usable tank volume is displaced by the carrier elements due to their high surface area per unit volume. The biofilm carrier elements are kept suspended in the water by air from the aeration system and/or mechanical mixers. Sieve assemblies are used to retain the biofilm carrier elements in the reactor. The continuous movement of the carrier elements, air knife systems, and other means are used to prevent clogging of the sieves.

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Conceptual Level Design for MBBR Option MEMORANDUM


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The biomass in a MBBR process is resilient against factors such as temporary limitation of nutrients, toxicity spikes, pH changes, and temperature changes. These factors may reduce the biological capacity of the biofilm system temporarily, but will not significantly affect the biomass in the reactor. The process will adjust itself to normal performance in a very short time after the shock. Since the biomass is attached to media, which is kept in the reactor using a sieve, the suspended/attached growth process is less susceptible to solids washout during peak wet weather flows than conventional ASPs.

Excess layers of biofilm fall from the carrier elements and are passed in the MBBR effluent to the secondary clarifiers. The concentration of the MBBR effluent is typically about 300 mg/L, which is considerably less than a conventional ASP. This results in a considerably reduced solids loading rate on the secondary clarifiers. However, the solids from the MBBR process typically do not settle as well as from a conventional ASP process. As such, the secondary clarifiers for an MBBR process are typically similar to a conventional ASP system. No RAS pumping is required with the MBBR process.

A significant disadvantage of the MBBR process is the high operating costs associated with the aeration process. The MBBR process generally uses coarse bubble diffusers which have very poor oxygen transfer efficiencies relative to the fine bubble diffuser systems commonly used in conventional ASP systems. Fine bubble diffusers are not used in the MBBR system because they tend to cause the media to float to the water surface. Furthermore, the manufacturer recommends a minimum dissolved oxygen concentration of 3 to 4 mg/L to maintain the aerobic conditions in the biofilm. As such, there would be a high energy requirement and power cost.

The MBBR process has been extensively tested under different conditions in pilot and full-scale plants since 1989. By 1999, 108 full-scale plants of different kinds and sizes were in operation or under construction in 16 countries. This process was developed in Norway and has been operated historically under similar climatic conditions as in Ontario. The process has demonstrated its ability to achieve nitrification under the extreme Norwegian climate. There are no full-scale applications of the MBBR process in Ontario. A moving bed biofilm process was successfully tested at the Waterdown STP (Jones et al., 1999), although Kaldnes media was not used in that case. The MBBR process with Kaldnes media has been tested at demonstration scale at the City of Toronto’s Highland Creek WWTP and has been piloted at the Brockville WWTP. It also included in a comparative evaluation of MBBR process configurations on-going at the Region of Peel’s Lakeview WWTP.

Phosphorus removal can be accomplished by alum addition before the secondary clarifier. Precipitation at this point of addition is typically more efficient than pre-precipitation and may result in some chemical cost savings. The TP, BOD5 and TSS removal efficiencies of the MBBR process would be similar to a conventional ASP. The MBBR can be configured to meet strict nitrification requirements by adding additional media to the reactors.



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2.1 Conceptual Design The conceptual level design for the MBBR process was provided by John Meunier Inc. (JMI), and is included as Appendix A. The effluent limits for the expanded WWTP have not yet been established by the MOE. For the purposes of this assessment, it was assumed that the plant would be required to nitrify in future. Projected loadings to the plant were based on historical 2005 to 2007 data. As part of the Class EA process, design flows and loadings will be reviewed, including the contribution from internal recycle streams. After the effluent limits have been established by the MOE, and the design flows and loadings determined, the MBBR conceptual design should be reviewed by JMI to confirm that the design provided is still appropriate.

For the Sudbury WWTP, the MBBR process would require the conversion of the four (4) existing aeration tanks to the MBBR process. One (1) additional aeration tanks would be required, for a total of five (5) aeration tanks. To achieve BOD reduction and nitrification, each aeration tank would be divided into three cells. The first two cells would be used for BOD removal and the third cell for nitrification. Each cell would be filled 62% with media. It should be noted that this design will limit the ability for future expansion (only 4% more of media can be added). There would no longer be a requirement for Return Activated Sludge (RAS) pumps. Sludge accumulated in the secondary clarifiers would be pumped directly to the sludge thickeners.

Table 1 presents the preliminary conceptual level design for the MBBR option for the expanded Sudbury WWTP.

Table 1 Conceptual Design for MBBR Parameter Value

Average Day Flow 102,375 m3/d

BOD Loading 14,742 kg/d (1)

TKN Loading 1,945 kg/d (2)

Number of Existing Tanks 4

Volume Per Tank 3,427 m3

Number of Additional Tanks Reqd 1

Total Volume of Tanks 17,135 m3

Media Fill in Aeration Tank (% v/v) 62 percent

Notes:

1. Based on average BOD concentration of 144 mg/L (2005 to 2007 data)

2. Based on average TKN concentration of 19 mg/L (2005 to 2007 data)

The additional secondary clarification for the expanded Sudbury WWTP was estimated based on literature values for an MBBR process. According to Metcalf and Eddy (2003), typical design surface overflow rate (SOR) values for an MBBR process range between 12 to 19.2 m3/m2/d (assumed on an average day flow basis). For one additional secondary clarifier, the SOR would be 16.5 m3/m2/d, on an average day basis, which is in the mid-range of typical values. One (1) new secondary clarifier, same size of the existing would be



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required for the expanded plant. Table 2 presents the additional secondary clarifiers required for the MBBR option.

Table 2 Secondary Clarifier Tank Requirements Parameter Value

Number of Existing Clarifier (1) 6

Number of New Clarifiers 1

Total Number of Secondary Clarifiers 7

Total Clarifier Surface Area 6,174 m2

Peak Design Flow 204,750 m3/d

Average Surface Overflow Rate 16.5 m3/m2/d

Peak Surface Overflow Rate 33 m3/m2/d

Notes:

(1) each clarifier has a surface area of 882 m2

Conceptual Level Design for MBBR Option APPENDIX


APPENDIX A CORRESPONDENCE WITH JMI REGARDING

MBBR PRELIMINARY CONCEPTUAL DESIGN

Hansler, Susan

From: Elliott, Wayne [[email protected]]Sent: August 21, 2008 9:58 AMTo: Hansler, SusanSubject: Fw: Sudbury MBBR Tankage

Page 1 of 7Fw: Sudbury MBBR Tankage

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Susan Please see Robert's comments below. Let me know if you require additional information or clarifications. Wayne Elliott Technical Representative John Meunier Inc. 2000 Argentia Rd, Plaza IV, Suite 430 Missisauga, ON , L5N 1W1 Tel. 905-286-4846 Fax. 905-286-0488 Cell: 519-525-2446 [email protected] www.johnmeunier.com This e-mail message and any attachments to it are intended only for the named recipients and may contain confidential information. If you are not one of the intended recipients, please do not duplicate or forward this e-mail message and immediately delete it from your computer. ----- Original Message ----- From: Lafond, Robert To: Elliott, Wayne Sent: Thu Aug 21 09:43:37 2008 Subject: RE: Sudbury MBBR Tankage Hello Wayne Effectively it could be possible to go with five trains of 3 MBBR reactors. The two first MBBR reactors for BOD removal would be 18,3 m W x 14,3 m long by 4,6 m SWD. The third reactor for nitrification will have 18,3 m W x11,9 m long by 4,6 m SWD. In this case an dditionnal train of MBBR would be required ( train #5). The media fill percentage would be around 62%. This design will not allow a lot of safety for the future ( only 4% more of media). Five trains of 18,3 m by 41,15 by 4,6 m SWD for a total biological volume of 17 190 m3. If you need more explanations, please call me. Regards Robert Lafond, ing. Chargé d'ingénierie Senior Project Manager John Meunier Inc. 4105 Sartelon Saint-Laurent (Québec) Canada H4S 2B3

Tel. (514) 334-7230 ext. 3313 Téléc./ Fax. (514) 334-5070 [email protected] www.johnmeunier.com ISO 9001 : 2000 This e-mail message and any attachments to it are intended only for the named recipients and may contain confidential information. If you are not one of the intended recipients, please do not duplicate or forward this e-mail message and immediately delete it from your computer. / Ce courriel et tous documents attachés sont destinés uniquement aux destinataires et peuvent contenir des informations confidentielles. Si vous n'êtes pas un des destinataires ou si vous recevez ce message par erreur, prière de ne pas le copier ni le transmettre à autrui et de l'effacer immédiatement de votre ordinateur. ----- Original Message ----- From: Lafond, Robert To: Elliott, Wayne Cc: Scott, Christian Sent: Wed Aug 20 16:37:31 2008 Subject: RE: Sudbury MBBR Tankage Hello Wayne I will give you my comments for tomorrow morning. Robert -----Message d'origine----- De : Elliott, Wayne Envoyé : 20 août 2008 15:48 À : Lafond, Robert Cc : Scott, Christian Objet : Fw: Sudbury MBBR Tankage Robert Please see the question from Susan Hansler at the beginning of this email string. Could you please provide your comments. Wayne Elliott Technical Representative John Meunier Inc. 2000 Argentia Rd, Plaza IV, Suite 430 Missisauga, ON , L5N 1W1 Tel. 905-286-4846 Fax. 905-286-0488 Cell: 519-525-2446 [email protected] www.johnmeunier.com This e-mail message and any attachments to it are intended only for the named recipients and may contain confidential information. If you are not one of the intended recipients, please do not duplicate or forward this e-mail message and immediately delete it from your computer. ----- Original Message ----- From: Hansler, Susan <[email protected]>


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To: Elliott, Wayne Sent: Wed Aug 20 15:41:44 2008 Subject: RE: Sudbury MBBR Tankage HI Wayne, I’m just following up to see if you’ve heard anything back from your Montreal office regarding my question for Sudbury? Susan ________________________________ From: Elliott, Wayne [mailto:[email protected]] Sent: August 13, 2008 10:08 AM To: Hansler, Susan Subject: RE: Sudbury MBBR Tankage Susan Robert Lafond, the Engineer in our Montreal office that is working on the Sudbury MBBR proposal is on vacation, returning next Monday. Hopefully your request for information can wait for his return, He is best suited to provide comment. Regards, Wayne Elliott, C.E.T. Technical Representative John Meunier Inc. Meadowvale Corporate Centre, 2000 Argentia Road, Plaza IV, Suite 430, Mississauga, ON L5N 1W1 Phone: 905-286-4846 ext.#2107 Fax: 905-286-0488 Cell: 519-525-2446 Email: [email protected] <mailto:[email protected]> www.johnmeunier.com <http://www.johnmeunier.com> ISO 9001 : 2000 A Veolia Water Solutions & Technologies Company Confidentiality note: This message and any attachments to it are intended only for the named recipients and may contain


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confidential information. If you are not one of the intended recipients, please do not duplicate or forward this e-mail message and immediately delete it from your computer. ________________________________ From: Hansler, Susan [mailto:[email protected]] Sent: August 12, 2008 10:37 AM To: Elliott, Wayne Subject: RE: Sudbury MBBR Tankage Hi Wayne, Sorry for the delay since your original proposal, but can you please clarify something for me. The proposal indicates that an additional cell would be provided at the end of each of the 4 existing tanks for an additional volume of 5,714 m3. As an option, it was indicated that the existing tanks could be converted into a 3 cell configuration, and construct a fifth (5th) tank identical to the other four (4), in order to provide the necessary volume. This will be the most likely layout due to the site constraints. The volume of each of the existing tanks is 3,427 m3, which is less than the additional volume required for the first configuration (5,714 m3). Can you please confirm that this is correct – would you add more media for this scenario to make up for the difference in tank volume? Thanks Susan ________________________________ From: Elliott, Wayne [mailto:[email protected]] Sent: July 18, 2008 1:20 PM To: Hansler, Susan Subject: RE: Sudbury MBBR Tankage Susan Sorry for the slip. It is nitrification. Wayne


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________________________________ From: Hansler, Susan [mailto:[email protected]] Sent: July 18, 2008 1:18 PM To: Elliott, Wayne Subject: RE: Sudbury MBBR Tankage Thanks Wayne, Is the third tank for nitrification or denitrification? ________________________________ From: Elliott, Wayne [mailto:[email protected]] Sent: July 18, 2008 1:11 PM To: Hansler, Susan Subject: Sudbury MBBR Tankage Susan JMI Engineering has a the chance to consider your request to evaluate the tankage requirements to install MBBR at the Sudbury (Kelley Lake) WPCP, providing complete nitrification. The plant would see a capacity expansion from the current ADF of 68,250 m3/day to an ADF of 102,375 m3/day. The new MDF would be 204,750 m3/day. Here is the proposal: 1. the four (4) existing aeration tanks would be used for BOD removal only. Each tank would be divided into two (2) cells. Each cell would be filled 55% with media. The tanks are broken into two (2) cells in order to prevent migration of the media to one end of the tank. 2. one (1) additional tank would need be constructed at the end of EACH existing aeration tank for denitrification. These tanks would each have a dimension of 18.3m wide X 17.1m long X 4.6m deep. Each tank would be filled 55% with media. It may be possible to increase the depth of these tanks, if the Consultant so wishes, in order to reduce the footprint requirement. 3. the total additional aeration tank volume would be 5,714 m3. In summary, each train would consist of MBBR #1 (BOD), MBBR #2 (BOD) and MBBR #3 (NH3-N) tanks. Engineering is still contemplating the effect that the retrofit of the MBBR into the existing process would have on the secondary clarification requirements. The TSS in the effluent from the MBBR is in the 150 - 300 mg/l range, as opposed to 3,000 - 5,000 mg/l TSS from the existing activated sludge plant. We will let you know as soon as this has been determined. There would no longer be a requirement for Return Activated Sludge (RAS) pumps. Sludge accumulated in the secondary clarifiers would be pumped directly to the sludge thickeners.


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If it is anticipated that the new ADF will not be reached for a period of time, it would be possible to convert the existing aeration tanks to MBBR now without constructing the additional tankage requirement. The tanks could be split into two (2) cells, and populated with media below the maximum allowable amount. As flows increased, additional media could be added, until the maximum allowable fill percentage was reached. The City then would construct the additional tankage required to meet the new ADF of 102,375 m3/day. In the above noted message, it is stated that a third cell would be added to the end of each existing aeration cell. It may also be possible to convert each of the existing trains into a three (3) cell configuration, and construct a fifth (5th) tank identical to the other four (4), in order to provide the necessary volume. This would be a decision of the Owner and Consultant as to which direction would be best to build any expansion. The overall footprint would remain the same. Please let me know if you have any questions, or require any clarifications regarding this message. Regards, Wayne Elliott, C.E.T. Technical Representative John Meunier Inc. Meadowvale Corporate Centre, 2000 Argentia Road, Plaza IV, Suite 430, Mississauga, ON L5N 1W1 Phone: 905-286-4846 ext.#2107 Fax: 905-286-0488 Cell: 519-525-2446 Email: [email protected] <mailto:[email protected]> www.johnmeunier.com <http://www.johnmeunier.com> ISO 9001 : 2000 A Veolia Water Solutions & Technologies Company Confidentiality note: This message and any attachments to it are intended only for the named recipients and may contain confidential information. If you are not one of the intended recipients, please do not duplicate or forward this e-mail message and immediately delete it from your computer. ************************************************************************* This e-mail message and any attachments to it are intended only for the named recipients and may contain confidential information. If you are not one of the intended recipients, please do not duplicate or forward this e-mail message and immediately delete it from your computer. If you received this email in error, please notify [email protected] ************************************************************************* ************************************************************************* This e-mail message and any attachments to it are intended only for the named recipients and may contain confidential information. If you are not one of the intended recipients, please do not duplicate or forward this e-mail message and immediately delete it from your computer. If you received this email in error, please notify [email protected] ************************************************************************* ************************************************************************* This e-mail message and any attachments to it are intended only for the


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named recipients and may contain confidential information. If you are not one of the intended recipients, please do not duplicate or forward this e-mail message and immediately delete it from your computer. If you received this email in error, please notify [email protected] ************************************************************************* ************************************************************************* This e-mail message and any attachments to it are intended only for the named recipients and may contain confidential information. If you are not one of the intended recipients, please do not duplicate or forward this e-mail message and immediately delete it from your computer. If you received this email in error, please notify [email protected] *************************************************************************


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071472-20090218-Appendix-L-XCG-Report-July-21-2008

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