ARKANSAS RECYCLING COALITION Alternative Sustainable Power September 19, 2017 Session A Walter B. Collins, P.E. Director of Operations & Facilities

So how exactly is wastewater (sewer) treatment… recycling So how exactly is wastewater (sewer) treatment… recycling and how on earth is it Alternative Sustainable Power..?? ?

So how exactly is wastewater (sewer treatment)… recycling So how exactly is wastewater (sewer treatment)… recycling and how on earth is it Alternative Sustainable Power..??

So how exactly is wastewater (sewer treatment)… recycling So how exactly is wastewater (sewer treatment)… recycling and how on earth is it Alternative Sustainable Power..?? There is Only One Water

This is clearly NOT a modern concept Pont de Gard Part of 50 km long aqueduct Stands 50 m high Spans 275 m across

This is clearly NOT a modern concept Housesteads Roman Fort: 124 A.D.

This is clearly NOT a modern concept

This is clearly NOT a modern concept 500 BC – Prosperous Chinese families had latrines in their houses 100 BC – Roman’s were building public toilets 124 AD – Housesteads Roman Fort (along Hadrian’s Wall) built with stone latrines 500 AD – Toilet paper developed in China (chopped mulberry bark and grasses) 700 AD – as China’s population grew, business opportunities developed for pay to use facilities – one stall mud huts Prior to 1958 – City of Little Rock had direct discharge into the Arkansas River (downstream of the city) 1972 – Clean Water Act mandated specific wastewater treatment standards

What is modern is our method of reclaiming this water:

What is modern is our method of reclaiming this water: We Grow Bugs…. Over 100,000 pounds

What is modern is our method of reclaiming this water:

What is modern is our method of reclaiming: One of Three WRF for Little Rock Average Daily 36 MGD reclaimed Wet Weather Capacity 145 MGD 5,500 Tons of Biosolids Non-biodegradable to landfill

What is modern is our method of reclaiming: 7.2 Million Gallons Anaerobic Digestion 95-100 deg F 15-20 day detention time 300,000 cubic feet biogas

What is modern is our method of reclaiming: 5,500 Tons of Soil Amendment Material 4N-3P-0.3K Nutrient Rating Water holding potential

Alternative Sustainable Power: Biogas Collectors Biogas (methane): 300,000 cf per day 650 BTU/cf <100 mg/L H2S

Alternative Sustainable Power:

Alternative Sustainable Power:

Alternative Sustainable Power: Gas line filters Pressure regulators for both systems

Alternative Sustainable Power: Tech-Jet gas mixing valves

Alternative Sustainable Power: GE Jenbacher JMS 320: 480 volts nominal 1060 kW*hr 20 Cylinder Dual fuel: biogas methane and/or natural gas

Alternative Sustainable Power: Original 1983 Eng/Get set: 18% gas to wire 545 kW*hr (3 units) Jenbacher Eng/Gen set: 38% gas to wire 6,050 MW annually

Alternative Sustainable Power: Paralleling Power Switchgear: Fiber optic comm with local substation SCADA Controlled to match plant demand Primary source of power Surplus power sold onto grid

Alternative Sustainable Power: Protective Sensors: 900 internal checks Engine timing (Lambda) changes to match biogas quality

Alternative Sustainable Energy: Heat Recovery Potential: Jacket water energy Lube oil energy

Alternative Sustainable Energy: Heat Recovery Potential: Jacket water energy Lube oil energy Exhaust gas energy

Alternative Sustainable Energy: Heat Recovery Potential: Roughly 2 million BTU/Hr Maintain digester temp: 95°F Savings of $650/day

Alternative Sustainable Energy: Supplemental Heat Potential: Roughly 6 million BTU/Hr Maintain digester temp: 95°F Complete Eng/Gen shutdown Dual fuel: biogas methane and/or natural gas

Alternative Sustainable Energy: Co-digestion of Industrial Wastes: 24,000 lbs of food grade waste Population equivalent: 120,000 High energy source Increases biogas production by 15%

In Summary: Combined Heat & Power: 300,000 cft biogas (650 btu/cf) Roughly 2 million BTU/Hr heat Approx 900 kWHr power Plant demand ~ 800 kWHr Parallel power production to grid 1 of 74 WRF (16,000 WRF) Power savings $1500/day Heat load savings $650/day

Thank You: Walter B. Collins, P.E. Director of Operations & Facilities Little Rock Water Reclamation Authority Walter.Collins@lrwu.com 501-688-1429