Alan L. Horton Alan L. Horton Wastewater Treatment PlantWastewater Treatment Plant

A Tour of the PlantA Tour of the Plant

Prepared by MSWDPrepared by MSWDUpdated July 2009Updated July 2009

Benefits to CommunityBenefits to CommunitySewer and wastewater treatment vs. individual septic tanksSewer and wastewater treatment vs. individual septic tanks

• • Sewer system and wastewater treatment protect our precious Sewer system and wastewater treatment protect our precious groundwater from potential contamination by septic tanks. groundwater from potential contamination by septic tanks.

• “• “Septic systems are second greatest threat to groundwater Septic systems are second greatest threat to groundwater quality quality

(as viewed by State water quality agencies).” (as viewed by State water quality agencies).” - from EPA’s “- from EPA’s “Decentralized Wastewater Treatment Systems: A Program StrategyDecentralized Wastewater Treatment Systems: A Program Strategy””

• • Sewers collect wastewater and convey it to the plant, Sewers collect wastewater and convey it to the plant, where it where it

is treated.is treated.

• • Treated water is percolated back into the ground.Treated water is percolated back into the ground.

Overview of Treatment ProcessOverview of Treatment Process

Sewage flows to plant for treatment.Sewage flows to plant for treatment.

The sewage is aerated, mixed and The sewage is aerated, mixed and concentrated. Naturally occurring concentrated. Naturally occurring microorganisms digest the waste.microorganisms digest the waste.

Secondary effluent is percolated Secondary effluent is percolated back into the ground.back into the ground.

Solids are dewatered and hauled away Solids are dewatered and hauled away to landfills, compost sites or applied to landfills, compost sites or applied

directly to the land as fertilizer.directly to the land as fertilizer.

Through The PlantThrough The Plant

Step

By

Step

Pump StationPump Station

Receives and lifts Receives and lifts the raw sewage into the raw sewage into the treatment the treatment process.process.

Currently designed to Currently designed to handle 2 MGD flow.handle 2 MGD flow.

Employs two 33.5 HP Employs two 33.5 HP and two 12 HP pumps and two 12 HP pumps

Channel GrinderChannel Grinder

Rotating screens Rotating screens channel debris into channel debris into two cutter stacks.two cutter stacks.

Debris may be organic Debris may be organic or inorganic waste.or inorganic waste.

Cutter stacks chew up Cutter stacks chew up large floating debris.large floating debris.

Vortex Grit RemovalVortex Grit Removal Grit has no use in the Grit has no use in the biological process and biological process and must be removed. Grit must be removed. Grit includes sand, gravel includes sand, gravel and other heavy, and other heavy, inorganic materials.inorganic materials.

Rotating paddles create Rotating paddles create a vortex causing the a vortex causing the grit to drop to the grit to drop to the bottom.bottom.

Grit drops into a sump Grit drops into a sump and is pumped to the and is pumped to the grit classifiers for grit classifiers for dewatering and disposal.dewatering and disposal.

Grit ClassifiersGrit Classifiers Grit Classifiers Grit Classifiers separate water from separate water from the grit, then drop the grit, then drop the solids into a the solids into a dumpster.dumpster.

The dumpster is The dumpster is hauled hauled to a landfill to a landfill weekly.weekly.

Aeration BasinsAeration Basins

After grit removal, After grit removal, the head works the head works splitter box delivers splitter box delivers the influent to the the influent to the relevant aeration relevant aeration basins.basins.

The sewage is mixed The sewage is mixed and aerated in the and aerated in the aeration basins. aeration basins.

Oxygen is required Oxygen is required for aerobic bacteria for aerobic bacteria to digest the waste.to digest the waste.

AeratorsAerators

Our 2 largest Our 2 largest aeration basins aeration basins hold 750,000 hold 750,000 gallons each.gallons each.

Our largest two-Our largest two-speed aerators run speed aerators run at 56 to 75 HP.at 56 to 75 HP.Aerator Driver

ClarifiersClarifiers

The clarifiers separate The clarifiers separate the solids from the the solids from the water. The settled water. The settled solids are returned to solids are returned to the head works to the head works to undergo further undergo further treatment.treatment.

Solids are routinely Solids are routinely removed for disposal.removed for disposal.

Our 2 largest clarifiers Our 2 largest clarifiers are 55 ft. in diameter are 55 ft. in diameter and 14 ft. deep.and 14 ft. deep.

Percolation PondsPercolation Ponds

Effluent from the Effluent from the secondary secondary clarifiers gravity clarifiers gravity flow to the flow to the percolation ponds.percolation ponds.

Here it percolates Here it percolates through a natural through a natural filtering process filtering process before returning to before returning to the water table.the water table.

Percolation PondsPercolation Ponds

The effluent is also The effluent is also used on-site for used on-site for equipment wash downs equipment wash downs and landscape and landscape irrigation. irrigation.

Reclaiming this water Reclaiming this water for golf course and for golf course and other irrigation uses other irrigation uses would require further would require further treatment. treatment.

Belt Filter PressBelt Filter Press

Sludge is dewatered Sludge is dewatered on a “belt filter on a “belt filter press,” which press,” which squeezes the water squeezes the water out of the sludge. out of the sludge.

The dewatered The dewatered solids are loaded solids are loaded into a trailer.into a trailer.

The trailers are The trailers are covered & hauled covered & hauled away when filled.away when filled.

The liquid filtrate The liquid filtrate is returned to the is returned to the treatment process treatment process head works.head works.

Controls & Electric SupplyControls & Electric Supply

The Treatment plant The Treatment plant controls are managed controls are managed in the electrical in the electrical room.room.

Uninterrupted power Uninterrupted power is assured by a is assured by a standby generator.standby generator.

Standby GeneratorStandby Generator

This 1502 HP diesel This 1502 HP diesel engine provides engine provides backup electricity.backup electricity.

Engine weighs over Engine weighs over 21,000 lbs.21,000 lbs.

Alan L. Horton Wastewater Alan L. Horton Wastewater Treatment Plant - HistoryTreatment Plant - History

Expansion 4 in October 2002 increased capacity Expansion 4 in October 2002 increased capacity from 1 million gallons per day (MGD) to 2 MGD.from 1 million gallons per day (MGD) to 2 MGD.

Expansion potential to 5 MGD.Expansion potential to 5 MGD.

Achieved without additional bond debt.Achieved without additional bond debt.

Expansion 5 is in the final design stage Expansion 5 is in the final design stage and is expected to be completed in 2010, and is expected to be completed in 2010, at a cost of approximately $10-14 at a cost of approximately $10-14 million. million.

A permanent belt press dewatering system A permanent belt press dewatering system is included in the expansion plans.is included in the expansion plans.

Expansion 5 will increase plant capacity Expansion 5 will increase plant capacity to 3MGDto 3MGD

Alan L. Horton Wastewater Alan L. Horton Wastewater Treatment Plant - On the HorizonTreatment Plant - On the Horizon

Alan L. Horton Wastewater Alan L. Horton Wastewater Treatment Plant - IndustryTreatment Plant - Industry

HWTP has won numerous prestigious industry awards:HWTP has won numerous prestigious industry awards:

• 2008 Plant of the Year (less than 5MGD category)2008 Plant of the Year (less than 5MGD category)

• 2008 Collection System of the Year (0-249 miles 2008 Collection System of the Year (0-249 miles category)category)

• 2007 Operator of the Year (Chris Jacobson, Operator)2007 Operator of the Year (Chris Jacobson, Operator)

• 2006 Plant of the Year (less than 5MGD category)2006 Plant of the Year (less than 5MGD category)

• 2006 Collections System of the Year (0-249 miles 2006 Collections System of the Year (0-249 miles category)category)

• 2006 Supervisor of the Year (Wayne Robertson, Chief 2006 Supervisor of the Year (Wayne Robertson, Chief Plant Operator)Plant Operator)

• 2006 Collection System Person of the Year (Lee Boyer, 2006 Collection System Person of the Year (Lee Boyer, Lead Operator)Lead Operator)

The awards were presented by the Colorado River The awards were presented by the Colorado River Basin Section (CORBS) of the California Water Basin Section (CORBS) of the California Water Environment Association (CWEA). Environment Association (CWEA).

Alan L. Horton Wastewater Alan L. Horton Wastewater Treatment Plant - CommunityTreatment Plant - Community

MSWD partners with community and education groups, such as MSWD partners with community and education groups, such as this middle school Earth Sciences class which toured the this middle school Earth Sciences class which toured the plant plant during a school field trip organized by the Desert Hot during a school field trip organized by the Desert Hot Springs Groundwater Guardian team.Springs Groundwater Guardian team.

MSWD participates in local school and community science fairs MSWD participates in local school and community science fairs and career days events, highlighting the broad range of and career days events, highlighting the broad range of careers available in the water industry and encouraging young careers available in the water industry and encouraging young people to take an interest in environmental sciences.people to take an interest in environmental sciences.