Ammonia Control for Landfill Leachate NC SWANA ANNUAL CONFERENCE Asheville, NC April 6, 2017

Agenda SWANA Leachate Survey Ammonia Nitrogen Background Effluent Limits Conventional Treatment Physical Treatment Biological Treatment Innovative Treatment

Q1: How is leachate presently managed at your landfill? Answered: 184 Skipped: 0

Q1: How is leachate presently managed at your landfill? Answered: 184 Skipped: 0

Q2: If discharged to POTW, how is it conveyed? Answered: 117 Skipped: 67

Q2: If discharged to POTW, how is it conveyed? Answered: 117 Skipped: 67

Q3: If discharged to POTW, what discharge limits must the leachate meet? Answered: 106 Skipped: 78

Q3: If discharged to POTW, what discharge limits must the leachate meet? Answered: 106 Skipped: 78

Q4: If pre-treated or treated on site, what discharge limits must the leachate meet? Answered: 54 Skipped: 130

Q4: If pre-treated or treated on site, what discharge limits must the leachate meet? Answered: 54 Skipped: 130

Why Control Ammonia? Why removal ammonia? – A nutrient, can promote algae growth/algae blooms – Can exert oxygen demand in receiving waterways – Free or un-ionized fraction is toxic to aquatic life Ammonia in Landfills Ranges from 100 to 2,000 mg/L • In certain cases, effluent ammonia limits based on limiting oxygen demand in receiver, • More often, limits set based on toxicity to aquatic life • “Free” ammonia fraction is toxic: NH4+ NH3 +H+ – Chronic toxicity limit ~ 0.02 mg/L (after mixing in receiver) – Acute toxicity limit ~ 0.1 mg/L (at end of pipe) • Impacted by pH and temperature • At pH 7.5, 15oC, about 1% of TAN is NH3-N – So to achieve 0.1 NH3, need to be below TAN of 10 mg/L

Ammonia in Landfill Leachate – Physical Chemical Breakpoint Chlorination Air stripping Ion exchange Chemical Precipitation – Struvite Transmembrane Chemical Sorption

Breakpoint Chlorination Sodium hypochlorite/chlorine gas oxidizes ammonia

Air Stripping Simple Air Stripping Closed Loop Air Stripping Pros: pH Adjust, Air Discharged to Atmosphere Cons: Removal Efficiency Limited by Operating Temperature Closed Loop Air Stripping Pros: No Air Emissions by Scrubbing, Conservation of Energy Cons: Higher Initial Cost and Operations, Disposal of Concentrated Ammonia Sulfate Thermal Destruction Air Stripping Pros: Oxidizer Controls Ammonia Release, No Concentrated Ammonia Sulfate Disposal Cons: Higher Initial Costs and Operating Costs

Air Stripping NH3 +H2O= NH4+ +OH- Controlled by pH and temperature High volumes air required Temp >150 deg F and pH 10 removes 80% ammonia – higher temp/pH = greater removal Scaling/foaming Advantages Disadvantages Possible recovery of ammonia for resale Potentially very high capital and O&M costs Most efficient at higher ammonia concentrations Scaling and corrosion are issues  Possibly cost effective with high ammonia levels and partial treatment sites Large quantities of acids and caustic chemicals required  High Efficiencies reported – 85% to 99.5% Chloride levels would be raised and may pose a discharge issue   High labor costs have been reported Air pollution control may be an issue

Selective Ion Exchange Naturally occurring zeolites or manufactured products clinoptilitie or polyermic exchangers - Dowex 50w-x8 or Purolite MN500 10-20 mg/g NH4+ Use as a polishing after biological treatment? Regenerant management – Treat or dispose as solids? Volumes of high strength regenerant require treatment – biological? Advantages Disadvantages Acts as a polishing step to remove residual ammonia Untried at full scale in leachate treatment systems   Requires installation of Ion Exchange Columns, pumping systems, regenerant chemical storage, regenerant flow processing by air stripping or electro-oxidation, biotreatment or possible sale of concentrated ammonia in regenerant.

Chemical Precipitation Precipitation of NH4+-N by forming magnesium ammonium phosphate (MAP) Advantages Disadvantages Installed ahead of SBR, may reduce ammonia and COD concentrations to be further treated Large quantities of additional chemicals to be added   Requires installation of chemical storage, feed systems, rapid mix, and clarification stage Untried at full scale in leachate treatment systems

Biological Treatment Technologies conventional activated sludge, sequencing batch reactors, membrane bioreactors, aerobic lagoons, trickling filters constructed wetlands. Uptake of ammonia during biological growth (heterotrophs vs. autotrophs)

Biological Nitrification • Ammonia Reduction by Nitrification is a two- step reaction: NH4+ +1.5 O2 +AOB = NO2 +2H++H20 NO2 +0.5O2 + NOB = NO3- – Nitrifiers do not use organic carbon as basis for growth (CO2) – Nitrification releases acid, use up alkalinity – 4.57 g O2 consumed per g ammonia oxidized to nitrate (supply more! – keep DO 3-5 mg/L) – Acid formed, consumes alkalinity, 7.14 g alkalinity per g NO3 – Nitrite intermediate almost never “stable”, nitrite oxidizers grow faster than ammonia oxidizers at typical leachate temperatures

Keys to Biological Nitrification Alkalinity – Alkalinity is the carbon source for nitrifier growth – Do not want to go below 50 mg/L as CaCO3, or pH – For 1,000 mg/L ammonia nitrified, require 200 mg/L alkalinity • 7.14 x 1000 +50 ~ 7,200 mg/L (can gain back with denitrification) pH – Optimal pH for nitrification between 7 - 8.5 – pH below 6 can lead to inhibition Low Oxygen – Nitrifiers are strict aerobes, inhibited at very low DO levels (Filamentous/foaming issues) – As long as DO > 2 mg/L, little impact on nitrifier growth rate Inhibitions Organic acids/metals/SRT Temperature Free ammonia toxicity

Biological Nitrogen Removal - Denitrification Denitrification is defined as growth of bacteria when nitrate is used as the terminal electron acceptor: Organic C + NO3 > Biomass +CO2 + N2 Different from aerobic growth in that nitrate is used instead of DO Majority of heterotrophic bacteria in WW treatment can use both oxygen and nitrate If oxygen is present, it will be used before nitrate Oxygen inhibits denitrification – why would bugs try harder? Reduces oxygens demand (energy!)/ returns alkalinity/ stable pH

Biological Nitrification Advantages Disadvantages Most commonly used technology Potentially costly capital Operators usually familiar with the processes High Energy Costs from oxygen demand Can be effective with close operation Susceptible to upsets Detailed process controls needed Sludge production to be managed

Innovative Ammonia Control Short-Cut Ammonia Removal Direct Ammonia Removal – deammonification Anammox (Anaerobic Ammonia Oxidation) Addition of Fixed Media (IFAS?) Transmembrane Chemical Sorption Aerobic Granular Sludge Electro-Oxidation

Short Cut Ammonia Removal Deammonification/Anammox Grows the anammox bacteria in gravity-separated granules. Hydroclone or high-rate clarifier settles granules, flushes out bacteria , keeps sludge age required for existing bacteria DEMON Oxidation of some ammonium to nitrite. Partial nitrification by Nitrosomonas; Reduction of nitrite where ammonium is used as electron donor. Some nitrite is oxidized to nitrate. This reaction carried out by anammox bacteria =deammonification. MBBR (three suppliers) DeAmmon® process from Purac/Läckeby AB ANITA™ Mox from AnoxKaldness/Veolia Terra-N® process from Clariant/Süd-Chemie AG Savings Energy Sludge Reduction CO2 emissions

Process Overview - Anammox Advantages Disadvantages 60% savings in aeration energy Very low growth rate (1/10th of nitrifiers) No methanol feed -100% savings in supplemental carbon Inhibited by oxygen Successful European experience Hard to start up Difficult to maintain

IFAS Media Addition Addition can upgrade existing processes Use in SBR or Aeration Basins Increases MLSS 3,000 mg/L – doubles? Can simultaneous nitrify and denitrify, reduce or eliminate methanol as carbon source

IFAS Addition to Activated Sludge/SBR Advantages Disadvantages Increase ammonia removal and throughput, well established technology Potentially costly capital Less sensitive to upsets or process variations Second aeration source under modules Can be installed simply and quickly Reduced sludge production

Transmembrane Chemical Sorption Raise pH and drive ammonia across membrane – Reject sold as fertilizer? 95% removal Liqui-cell Process by Membrana

Transmembrane Chemical Sorption Acid solution removes ammonia gas from flow Then sulfuric acid reacts to form ammonium sulfate Ammonium sulfate can be sold as fertilizer Untried with Leachate Advantages Disadvantages Compact module design with Single step In-line processing Untried at full scale in leachate treatment systems Lab data – 95% ammonia removal Manage concentrated stream with other technologies  No air emissions Adjust pH with high chemical cost, then neutralize Possible cost recovery from fertilizer sale What to do if can’t sell fertilizer?

Electro Oxidation – One Step Direct electro-oxidation of ammonia (XOGEN Technology) Low power Releases nitrogen and hydrogen gas Capture & use? Modules in containers placed at end of existing process

Electro Oxidation – Two Step A two step process, first, use ion exchange to concentrate the ammonium by electrodialysis. Then, treat the concentrated ammonium stream with electro- oxidation (Enpar and Saltworks). Capture ionic fluid – expensive Planned to use solar power ?

Electro-Oxidation Technology Advantages Disadvantages Ammonia Electrolysis-efficient for removal of ammonia from leachate by direct conversion to nitrogen Untried at full scale in leachate treatment systems Lab data – 95% ammonia removal to 1 mg/L Two step system more complicated, expensive ionic fluid Generate hydrogen – use in CHP? pH adjustment may be needed Short detention time ~ 80 mg/L per minute Air emissions considerations for Hydrogen – blending with large volumes air for LEL Easy to operate – On/Off startup Two Step has higher capital and O&M cost and more complex operation No nitrous or nitric oxides produced Long term operations unknown

Aerobic Granular Activated Sludge - Sequencing

Aerobic Granular Activated Sludge Advantages Disadvantages Enhanced settling One Supplier – Aqua-Aerobics Reduced footprint – 75% possible Long Startup or haul granules from others (Europe/ WI?) Energy savings 0.5 mg/L DO Untried with Leachate Simultaneous nitrification Denitrification – Save methanol use

Summary Ammonia and nitrogen control becoming more frequent Many ways to remove ammonia from leachate Existing and Innovative technologies to consider Costs depend on process, concentrations, effluent limits Possible reuse or disposal of rejects CAPEX versus OPEX Recommend bench and pilot scale tests Look beyond costs – space needed, utilities, ease of operation, speed of implementation needed Part of Base Process or consider “bolt-on” technology. Lots to consider!!

Ammonia Control for Landfill Leachate Questions? Ammonia Control for Landfill Leachate Contact: Ivan Cooper, PE, BCEE Civil & Environmental Consultants, Inc. 1900 Center Park Drive Charlotte, NC 29217 Tel: 980-237-0373 icooper@cecinc.com