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Arsenic Treatment – Hopi Case Study. RCAP National Conference New Orleans, LA April 26, 2018. Second Mesa, Hopi. 7,000 residents 12 villages 1.5 Million Acres Arid - 8.5” of precipitation annually. Hopi Reservation in NE Arizona. Spring water for irrigation and ceremonies.
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Arsenic Treatment – Hopi Case Study RCAP National Conference New Orleans, LA April 26, 2018
7,000 residents • 12 villages • 1.5 Million Acres • Arid - 8.5” of precipitation annually Hopi Reservation in NE Arizona
Drinking Water • Deep groundwater (500’+) • Each village has its own system and operator • Not all households have running water
Arsenic Treatment Systems • 5 villages, 2 schools + 1 hotel affected • Only 4 treatment systems in place: • Only 3 are functioning • 3 different types • 2 exceeded MCL within the past 18 months • HAMP (Hopi Arsenic Mitigation Project) pipeline project by 2023??
Case Study #1 – Second Mesa Day School • K – 6 School • 376 students + staff • Arsenic = 18 ppb
RCAC Assistance – Second Mesa Day School • Installed in 2013 • Out of compliance by 2016 • New operator never trained on system • Overly complicated system
RCAC Assistance – Second Mesa Day School • Summer 2017 • Replaced pH probe + filters • Switched to manual control on CO2 • Re-calibrated CaCl2 • Back in Compliance by Q3 2017!
Case Study # 2 – BIA Keams Canyon • CWS serving 861 people • BIA housing & offices (funding) • Arsenic = 30 ppb
Package Plant + External Contractor • Installed in 2013 • Package plant (Adege) • Managed by External Contractor • Still in compliance
Comparison • Package plant vs. Piecemeal design • Specialized contractor vs. in-house operator (learning curve) • Annual Recurring Costs: • Contractor = $60/capita/year • In-house = $45/capita/year • Compliance!
Challenges with Arsenic Treatment • pH Control!! – media charge is pH dependent • Arsenic may be released with high pH • pH alarm / shut-off is necessary • High costs of filter media • >$25/capita/year on filter media • Complex • High-level operator or specialized contractor
Rural Community Assistance Partnership, Inc. WesternRural CommunityAssistance Corporation916/447-2854www.rcac.org MidwestMidwest Assistance Program952/758-4334www.map-inc.org SouthernCommunities Unlimited479/443-2700www.crg.org NortheastRCAP Solutions800/488-1969www.rcapsolutions.org Great LakesWSOS Community Action Commission800/775-9767www.glrcap.org SoutheastSoutheast Rural Community Assistance Project866/928-3731www.southeastrcap.org 800/321-7227 www.rcap.org