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solids by the autothermophilic aerobic digestion (ATAD) process. An ATAD system would be installed in close proximity to the existing solids handling building (two 23’x23’x28’ tanks assumed). Solids wasted from the clarifiers would be thickened using the existing SOMAT screw presses (assumed able to handle design capacity of existing facility), preheated (with spiral heat exchanger), and delivered to one of the ATAD tanks. Stabilized biosolids would then be removed from one of the ATAD tanks, cooled, and delivered to the quick dry filter beds for dewatering. When the desired dryness is reached, the solids could be removed and stockpiled at the existing solids holding area or the remaining sand drying beds for pickup and use throughout Prescott Valley as a soil conditioner/fertilizer for parks, offices, and private residences.

Belt Filter Presses/On-Site Solids Storage/Contract Hauling & Beneficial Reuse In this approach two two-meter belt filter presses would be installed interior of a building in close proximity to the existing solids dewatering building. Two presses will be required to dewater (during a 5 day per week 8 hour per day operation – based on 71,250 gal/day wasted & 160 gal/min feed rate to press) the amount of waste sludge produced at this studies design flows and loads. The dewatered sludge (15%-20%) would be stockpiled and maintained on-site for 90 days on an impervious asphalt pad measuring 200’

x 500 ‘ (this evaluation assumes the purchase of 2.5 acres of

evaluation).

Class

B

biosolids

produced

in

this

scenario

would

land – cost included in financial be removed by a contactor and

beneficially reused outside of Prescott Valley.

Belt Filter Presses/Agitated Air Drying and Curing In this approach two two-meter belt filter presses would be installed interior of a building in close proximity to the existing solids dewatering building. Two presses will be required to dewater (during a 5 day per week 8 hour per day operation – based on 71,250 gal/day wasted & 160 gal/min feed rate to press) the amount of waste sludge produced at this studies design flows and loads. The dewatered sludge (15%-20%) would be applied to an impervious asphalt pad measuring 400’ x 500’ (this evaluation assumes the purchase of 5 acres of land – cost included in financial evaluation) to allow for additional drying and curing. Agitation of the windrows and augmentation of the 15%-20% solids with dryer (65%) stabilized solids would be necessary to expedite the stabilization process. This size pad would allow for a greater than 5 month storage

capacity, allowing throughout Prescott

the biosolds to meet Class A standards. valley as a soil conditioner/fertilizer for parks,

The biosolids could then be offices, and private residences.

used

Belt

Filter

Presses/Autothermophilic

Aerobic

Digestion

In this approach two two-meter belt filter

presses would be installed interior of a building in close proximity to the existing solids dewatering

building. Two presses would be required even though the ATAD volume to be handled by more than 50%. This is due to the fact necessary in case of a mechanical failure of the other press. The

system will reduce the solids that a standby press would be ATAD system would also be

installed in close proximity to the existing Solids wasted from the clarifiers would

solids handling building (two 23’x23’x28’ tanks assumed). be thickened using the existing SOMAT screw presses

(assumed able to handle design capacity of existing and delivered to one of the ATAD tanks. Stabilized

facility), preheated (with spiral heat exchanger), biosolids would then be removed from one of the

ATAD

tanks,

cooled,

and

delivered

to

the

belt

filter

press

for

dewatering.

The

solids

could

then

be

removed and stockpiled at throughout Prescott Valley

the existing solids holding area of the sand drying beds for pickup and as a soil conditioner/fertilizer for parks, offices, and private residences.

use

Biosolids Enrichment and Recycling

In this approach a biosoldis enrichment

plant

would

be

constructed

at

the

WWTP

site.

The

facility

would

include

and one

recycling (BER) belt filter press,

chemical reaction tanks and bulk storage, one rotary drum (as proposed by vendor). The system would be computer

dryer, and necessary conveyance systems monitored. The system would produce a

potentially marketable fertilizer pellet. The final product by adjusting chemical feeds to

operator would have the reaction tanks.

the

ability

to

vary

the

makeup

of

the

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