Process & Equipment – ECM’s

1. Process & Equipment – ECM’s

2. Common Energy Conservation Measures ECM’s • Screening – very low energy use, look at control strategy • Influent pumping – maximize wet well level • Grit – Optimize blower use if aerated; change sheaves to reduce power use; pump only 15 minutes per hour • Primary – Remove as many solids as possible as it reduces load on aeration; sludge and scum pumping largest user in primary; optimize pumping • Secondary – blower use high – use inlet vanes, vari-speed blowers, fine bubble diffusers; DO control; optimize DO level; timers; speed control; control header pressure

3. Common ECM’s • RAS pumping can be significant since it is 40 to 100% of total forward flow. Time cycles • WAS pumping only 1 to 3% of influent flow, but may have a high head • Disinfection – low use, but high use of energy to produce hypochloriteor UV • Filtration – most energy use in backwashing, esp if air scour; if demand billing, may be able to backwash at off-peak power rates

4. Common ECM’s • Sludge Thickening – Gravity thickening, rotary drums, and belt thickeners are low energy consumers • Sludge stabilization – aerobic digestion is a high energy user, using a blower to introduce air. Anaerobic digestion is a producer of energy. It only requires mixing. Mix intermittently; interim operation of heater recirculation pumps; mix/recirculate off-peak hours • Sludge dewatering – belt presses use low energy; centrifuges are high energy consumers, however produce a drier cake; filter presses use moderate energy and produce a drier cake

5. Common ECM’s Pumps • Vary RAS pumping with sludge blanket levels • Run RAS in on/off mode, esp. with nightly low flows(CAUTION) • If have multiple pumps give more run time to most efficient pumps • If several large pumps consider having a smaller pump to handle lower flow periods • Increase wet well level or reduce pumping head • Add VFDs • Timers for on/off operation • Reduce recycle flows (filter wash, foam sprays etc.) • Flush lines periodically • Trim impellers

6. Common ECM’s • Activated Sludge Systems • D.O. Control • ON/OFF Timer • Diffuser Cleaning & “Bumping the Diffusers • Convert from Course Bubble to Fine Bubble • Lower D.O. setpoint • Adjust air drop valves • D.O. sensor location • Reduce number of aeration basins • Reduce pounds of solids • Look for boils or unusual bubble pattern • Replace or clean fine bubble diffusers

7. Common ECM’s • Blower Systems • Repair leaks • Perform O & M – Clean Filters, bearing lubrication • Blower intake use outside air vs room air • Clean and check D.O. sensors periodically • Reduce air header pressure if possible • Adjustable speed blowers • New Blower technology – Turbo Blowers • Reduce air flow where possible • Two blowers ON can one handle demand

9. Common ECM’s • Mechanical Mixing Systems • Confirm Submergence depth • Perform O & M – Check for accumulations • Reduce the number of mixers if possible • Consider not mixing pumped recycle zone

10. Other Systems • Ventilation & Odor Control - Reduce air flow to minimum needed to control odor and ensure required air changes per hour • Can the system only be run seasonal when odors are the worst • Can ventilation be run on/off cycles • Ultraviolet System – keep lamps clean and remove scaling • Replace lamps with high output lamps • Lighting – Turn off unneeded lights • Use occupancy sensors • Switch bulbs (T5,LED) • Laboratory- Turn off muffle furnace and unused equipment

11. Building HVAC Systems • Can area heater /air conditioning only be used only when people are working the area • Clean air filters • Have units tuned for maximum efficiency • Use automatic thermostats • Use timers or occupancy sensors • Can heat from blower room be directed to other area • Can boiler heat be directed elsewhere

12. Plant Process Control Systems

13. Plant Process Control Systems