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HomeMy WebLinkAbout08.a.1) (Handout) Plant Optimization for Ammonia Removal EvaluationItem No. 8.a.1) Plant Optimization for Ammonia Removal Evaluation Element 1: Plant Optimization (near term w /existing facilities) II Primary Baffle Study II Samantha Engelage, P.E. Assistant Engineer Treatment Plant Planning September 5, 2013 Central Contra Costa Sanitary District Nutrient Facility Plan & Site Characterizationli Element 2: utrient Visioning Plan (long term w /new facilities) Total Nitrification Study (2010 HDR) BioWin Configuration I ' Plant Optimization for Cutting -Edge Tact Ammonia Removal Evaluation Cyanide Study Nitrification Rate Tests vanide Removal Options Element 3: Site characterization (contaminated soil disposaittreatment for new facliftiesl ,�21_1 k Aandmi� Objectives • Evaluate modifications to existing: — Secondary treatment facilities that would enable ammonia removal in the near -term with low capital investments — Plant -wide facilities that would increase ammonia removal capacity I Current Secondary Configuration N RAS flan North S-dary CW im II 11 11 11 Ex= Ge&e (C) N I 1 ------------- Pmtarry Effluent (FE) 1 Eietirg Get. II 1 tGpe 11 _ to IB 1 1 1C ID 417 2C 2B 2A li i� :•IOm Gate it �1 A L + PAS hom SOC FA 3 1.0. ecoMery Clarlh.n LEGEND 1* Pmnary E"'u.nt F.W ;�Prinnry EttWOnI Figure 7 CURRENT CONFIGURATION CENTRAL CONTRA COSTA SANITARY DISTRICT Evaluation Summary n.N�.,w c.Myv.Nn wnaaer. FIR- 6 mu�.ns. vw�+mwwn..w�A S..pr an. us.�w INO A 60NM11C CEN7RALCONN OSTAS AMiANY 067WCi Secondary Reconfiqurations Description ',Near Definition Term Ammonia Removal Approach Plug -Flow Activated Sludge Scenarios Minimal horizontal mixing of water, 100% of the flow 7 treated via suspended growth, conventional biological ammonia removal (e.g. nitrification). Step -Feed Activated Sludge Plug -flow activated sludge with multiple feed points to equalize the food -to- microorganism ratio and decrease peak oxygen demand; 100% of the flow treated via suspended growth, conventional biological ammonia removal (e.g. nitrification). Plug -Flow Activated Sludge, Split 2 parallel treatment streams (BOD and NH4); portion of Treatment the flow treated via plug -flow activated sludge; effluent of 2 streams are blended prior to discharge for overall reduction in ammonia Step -Feed Activated Sludge, Split 2 parallel treatment streams (BOD and NHJ; portion of Treatment the flow treated via step -feed activated sludge; effluent of 2 streams are blended prior to discharge for overall reduction In ammonia Upstream Improvements Results Bioaugmentation Sidestream biological ammonia removal on a high- strength stream; used to seed the mainstream process with ammonia removing rSidestream microorganisms. 2^d Removal Remove screenings (i.e. rags, plastics, eta) from the wastewater combined with performance improvement options); and stream prior to primary treatment; Increases secondary treatment required blower upgrades to meet peak aeration capacity within the same footprint by removing inert solids earlier In Step -Feed Activated Sludge 161 Operational Complexity the process. V Near Term Preferred Ammonia Removal Approach Chemically Enhanced Primary Treatment Addition of coagulation chemicals upstream of primary treatment for Scenario Step-Feed Activated Sludge, Split Treatment is enhanced primary settling; increases secondary treatment capacity within the same footprint by removing more solids earlier in the 1° Not applicable as CCCSD does not digest sludge Screenings Removal process. Preferred Performance Improvement Option Chendcaliy Enhanced Primary Treatment Ammonia Recycle Reduction Reduce ammonia in the centrate recycle stream by limiting the nitrification, Incinerator clinkers, UV fouling, eta) retention time of the sludge blending tank; decreases the ammonia 1" Loss of sludge storage capacity & operational flexibility Primary Effluent Ammonia Load Equalization load to the secondary treatment process. Loss of wet weather capacity Equalized Peak Wet Weather Reduction Primary Effluent Ammonia Load Equalization Diumai flow equalization to even out daily peak loads to the Sludge Re- aeration 2ti Compliance risk when combined with Scenario 1; not secondary treatment process. appicabe to preferred ammenla removal a roach Equalized Peak Wet Weather Reduction Increased peak wet weather bypassing to avoid biomass washout and allow for higher biomass Inventory without Increased footprint. Sludge Re- aeration Temporarily operate secondary process in step -feed operation during peak wet weather events to allow for higher biomass inventory without increased footprint. Evaluation Results Plug -Flow Activated Sludge 2^d Compliance risk (unstable nitrification even when combined with performance improvement options); and required blower upgrades to meet peak aeration demands Step -Feed Activated Sludge 161 Operational Complexity Plug -Flow Activated Sludge, Split Treatment V Near Term Preferred Ammonia Removal Approach Scenario Step-Feed Activated Sludge, Split Treatment is Operational Complexity Sidestream Bicaugmentation 1° Not applicable as CCCSD does not digest sludge Screenings Removal 3" Preferred Performance Improvement Option Chendcaliy Enhanced Primary Treatment 2n0 Cost prohibitive, operationally complex (e.g. unstable nitrification, Incinerator clinkers, UV fouling, eta) Ammonia Recycle Reduction 1" Loss of sludge storage capacity & operational flexibility Primary Effluent Ammonia Load Equalization 1" Loss of wet weather capacity Equalized Peak Wet Weather Reduction to Loss of wet weather capacity Sludge Re- aeration 2ti Compliance risk when combined with Scenario 1; not appicabe to preferred ammenla removal a roach Plug -Flow AS, Split Treatment /N1 P0.51rom North /� 4\ s—MOry ct miery New Gate ,:Pen) Q/ �T '. '. r r E>t•e4rg)Gate ,w OemoaM ti i ; m p �a� �y� Reroute ! , 1 - Pump Rr15 Over Gaze 01 PAS Pipirg i r i - LLLL _LLLL_J a 0 Pmgfflut(PE) `00 E clim Gate '6 lop n9 � `^ - B�D Remc val 1Y 44 R mo I al ~9 S(�� d 2 days S T -: 7 da s,, t Oo 01* = 10- 8'pmg FJ i = 20111 o N rth Clanfiers So ith Clari!ers z. Exiclirp Gaze t FWS .,y South x Sonoary CWrifien LEGENG Flgura 10 Ridogicat Se:xtor puwerazea) SCENARIO 3 F Pr.mary Etmwm roeee SPLIT TREATMENT, PLUG FLOW' [ P, _'V Emuom CENTRAL CONTRA COSTA SANITARY MSTRICT Screenings Removal • Description: - Screenings = rags, plastics, non - biodegradable material, etc. - Currently 3/4" screens, ground screenings reintroduced to main wastewater stream - 2011 RMC Report recommended 3/8" screens with removal at Headworks • Benefits: - Increase solids capacity of existing facilities - Predicted annual NH4 removal increased by -7% - Reduce O &M issues (e.g. clogging, UV transmittance) - Currently in Capital Improvements Plan ($7.35M) Limit Comparison . Allowable .. .... Recommended .... Average Monthly` 65 27 15 (mg/L NH,-N) Average Monthly 5,500 3,888 — (kg /day NH3 N) Maximum Daily 84 29 20 (mg/L NH3 -N) 'Calendar month "Based on current NPDES permit limits ­2011 data " "Based on model simulations for 2030 flows and loads for both Plug -Flow Activated Sludge, Split Treatment and Screenings Removal aP_ Cost Estimates "Association for the Advancement of Cost Engineering International, Recommended Practices & Standards (T) Conclusions • Interim ammonia limits: > 15 m /L monthly average > 20 mg /L max. daily 4 use Plug -Flow AS, M� Split Treatment & ,r Screenings Removal Next Steps Field verification of assumptions and limiting parameters — Redundancy /complications of running 2 systems — Modeling predictions — Clarifier capacities (North vs. South) — Site - specific nitrification rate (bench vs. full - scale) 4.� .r 4V ti b�yi�. Questions? � v 1. �/