LEMNA BIOLOGICAL TREATMENT PROCESS LEMTEC TM TECHNOLOGIES, INC.

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1 LEMNA TECHNOLOGIES, INC. I n n o v a t i v e W a s t e w a t e r T r e a t m e n t S o l u t i o n s LEMTEC TM BIOLOGICAL TREATMENT PROCESS

2 LEMNA For more than 20 years, Lemna has been the world leader in high-performance lagoonbased wastewater treatment technologies. With more than 300 installed systems, Lemna's expertise encompasses all aspects of project development, from conceptual design to final commissioning and ongoing customer support. Headquartered in Minneapolis, Minnesota, Lemna designs and supplies systems for municipal and industrial applications. Whether supplying a floating cover to control odor and algae, or a complete wastewater treatment system to meet strict limits, Lemna devises a solution to meet each customer's needs.

3 THE SOLUTION IS SIMPLE... LEMTEC BIOLOGICAL TREATMENT PROCESS The LemTec Biological Treatment Process (LBTP) is a simple and affordable lagoon-based treatment system for industrial and municipal wastewater. The process is low maintenance, operator-friendly and easily expandable. Compared to traditional activated sludge plants, the LBTP offers the same high effluent quality at much lower capital and operating costs. The LemTec Biological Treatment Process (LBTP) treats wastewater as it flows through a series of aerated lagoons that are divided by baffles to reduce short-circuiting. Because our engineers customdesign each treatment plant, the process parameters can vary from site to site. These variations include the number of cells in each lagoon, their detention times and the exact combination of complete and partial mix aeration. In colder climates, each cell is covered by a LemTec Modular Cover, which enhances system kinetics, retains heat, controls odors, and prevents algae growth. In warmer climates, it may be necessary to cover only the final settling cell in order to promote digestion of sludge and prevent algae growth. Additional technologies including the Lemna Polishing Reactor, and the Lemna Phosphorus Removal System may also be used in a LemTec Biological Treatment Facility for enhanced nutrient removal....for NEW CONSTRUCTION OR RETROFIT OF EXISTING LAGOONS

4 THE LEMTEC TM ADVANTAGE Low Cost Low Capital Cost: Reduced footprint and simple equipment Low Operational Cost: No sophisticated systems or equipment Low Maintenance Cost: No daily sludge handling needed Lemna Polishing Reactor Ease of Operation No complex operating parameters to monitor or adjust No complicated sludge handling No highly skilled operators needed for efficient operation LemTec TM Biological Treatment Process Facultative Upgrade

5 THE LEMTEC TM ADVANTAGE Covered System Advantages Accelerated treatment kinetics through heat retention Ability to nitrify and reduce Ammonia Nitrogen year-round Algae prevention by blocking sunlight Evaporation control Odor control LemTec TM Modular Cover Flexibility and Expandability Allows for hydraulic flow variations and temperature fluctuations Adapts easily to surges in organic loading Easy expansion for increased flow or to meet stricter effluent limits without major capital outlays LemTec TM Biological Treatment Process New Construction

6 THE LEMTEC BIOLOGICAL TREATMENT PROCESS TM INFLUENT PRETREATMENT COMPLETE MIX CELL #1 PARTIAL MIX CELL #2 PHOSPHORUS REMOVAL EFFLUENT SETTLING CELL #3 LPR Cell 2: Partial Mix Cell Sufficient aeration and mixing to keep solids in suspension Typical detention time of 4-6 days Soluble BOD typically reduced by 40% in this cell Cell 1: Complete Mix Cell Aggressive aeration Fine bubble diffusers and floating mechanical mixers Typical detention time of 4-6 days Soluble BOD typically reduced by 80% in this cell Cell 3: Settling Cell Quiescent anaerobic zone settles out TSS and promotes digestion of sludge over years of storage Typical detention time of 4 days Volume of sludge greatly reduced compared to typical lagoon systems

7 LEMNA PHOSPHORUS REMOVAL SYSTEM INFLUENT PRE- TREATMENT AERATION PHOSPHORUS REMOVAL SETTLING LPR EFFLUENT The Lemna Phosphorus Removal System is a low-maintenance technology that transforms soluble phosphorus to a particulate form, which is then removed through flocculation and sedimentation. This automatic chemical feed process consistently meets effluent phosphorus (P) limits of 1 mg/l without the use of mechanical clarification or tertiary filtration. The Lemna Phosphorus System mixing chamber is located in an enclosed building between the aeration cells and the settling cell in an LBTP system. Can Meet Limits as Low as: Phosphorus < 1 mg/l Lemna engineers carefully analyze phosphorus concentrations, TSS, ph, and alkalinity to establish the correct chemical type to be used. The system is designed with sufficient chemical storage capacity to allow operators to take advantage of bulk chemical pricing and to alleviate day-to-day chemical handling. The automatic feed controls are pre-engineered to dispense chemicals according to pre-set levels. Lemna Phosphorus System Benefits Proven technology with predictable results Self-operating enclosed system, easily added to any existing system Promotes settling of TSS through flocculation Optimal integration with LemTec settling cell Automated process requires little operator oversight

8 LEMNA POLISHING REACTOR INFLUENT PRE- TREATMENT AERATION PHOSPHORUS REMOVAL SETTLING LPR EFFLUENT The Lemna Polishing Reactor (LPR) reduces Ammonia Nitrogen (NH 3 -N) and BOD in new or existing wastewater treatment facilities. The LPR is an optional component of a LBTP system and can be easily added for enhanced nutrient polishing as limits become stricter. The LPR is located prior to the effluent discharge where BOD and TSS are low, allowing bacteria to function at peak efficiency. The LPR offers a simple solution for complex wastewater treatment problems using Lemna s patented, operator-friendly technology. Can Meet Limits as Low as: BOD < 10 mg/l NH 3 -N < 2 mg/l Lemna Polishing Reactor Design Submerged, attached-growth media modules Large surface area for bacterial film growth Efficient conversion of ammonia to nitrates and nitrites Even distribution of air through coarse bubble diffusers Open-air concrete tank allows for short detention time

9 LBTP RETROFIT DESIGNS LBTP systems can be easily adapted to existing aerobic lagoons and facultative ponds. A LBTP upgrade can improve efficiency, meet stricter limits or accommodate higher flows. The LemTec TM system's versatility provides solutions at low capital cost by enhancing the treatment capabilities of an existing facility without additional heavy construction. Facultative Lagoon Upgrades Case Study: Ashdown, Arkansas The existing system was a 94,000 square foot facultative lagoon with a detention time of 102 days. As is the case with many facultative processes, algae growth in the Ashdown pond caused high TSS levels, which had to be reduced to meet new mandated limits. Lemna separated the last portion of the lagoon with a baffle and covered this area with a LemTec TM Modular Cover to create a discrete settling zone. The cover improves solids clarification by preventing wind action on the water surface in order to create a quiescent zone for solids to settle. In addition, the cover prevents the growth of algae by blocking sunlight. Lemna also added an aeration system of surface aspirators to the facultative cell, lowering the overall BOD loading in the system. Tertiary treatment was added with the inclusion of a Lemna Polishing Reactor at the effluent end for subsequent BOD removal. Ashdown s LBTP retrofit has provided improved results while maintaining the low energy costs and low maintenance requirements of a conventional facultative system. Upgrade to Meet New Limits: BOD 10 TSS 15

10 LBTP RETROFIT DESIGNS Aerated Lagoon Upgrades Case Study: Elk Lake, Pennsylvania The existing system was a 16,704 square foot circular lagoon divided into 4 cells. Due to much sludge accumulation and low water temperatures, the system was not achieving efficient results and couldn t meet new EPA limits for Ammonia Nitrogen removal. Before After Lemna de-sludged the lagoon and installed supplemental aeration equipment and a LemTec Modular Cover for enhanced treatment. The LemTec Cover lowered TSS levels and provided heat retention, which resulted in lower total Ammonia Nitrogen. The new aeration system helped to reduce total BOD and TSS. WINTER AMMONIA NITROGEN RESULTS Upgrade to Meet New Limits: BOD 25 TSS 30 NH 3 Winter 13.5 NH 3 Summer 4.5 NH MG/L After Cover Installed: 2004 After Aeration Installed: 2005 January February March MONTH

11 LEMNA TECHNOLOGIES, INC PARK AVENUE MINNEAPOLIS, MINNESOTA, U.S.A PHONE: (612) FAX: (612)