- Model BT125 125 - Duplex Batch pH Adjustment System

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batchTREAT - Model BT125 125 - Duplex Batch pH Adjustment System

The system featured here is a BT125 from our batchTREAT family of pH adjustment systems. This system consists of two identical batch pH adjustment systems on a common skid. Each system is independent and autonomous. Capable of treating peak flows of over 200 gpm and an average flow of 125 gpm and featuring redundancy of critical components. One side of the system can be 'of line' for service while the other remains running. This system is equipped with a first stage influent equalization pre-treatment system (not shown) and bulk caustic assist and bulk acid assist. The bulk chemical assist option allows concentrated acids and alkaline effluent streams to be neutralized in an expeditious manner.

System Performance Specifications:

This pH Neutralization system is an example of our venerable batchTREAT BT125 duplex batch pH adjustment system that is capable of handling flows in excess of 200GPM. Although actual throughput is a function of water chemistry. This system is comprised of two identical treatment systems offering redundancy of all critical components. Each unit operates autonomously, this means that one system can be totally shut down while the other continues to function normally. Bulk Reagent Assist is used on this system to improve treatment times when treating highly acidic or caustic material.

Influent Characteristics: Flow 50-250 GPM, 125 GPM Nominal Flow. Influent pH 0-14 pH units. Temperature 32-140 F. High solids loading.

Effluent Characteristics: Flow, batch discharges @ 260GPM. Nominal discharge flow 9,000 GPH. Note: Actual throughput is a function of water chemistry and can be significantly less with highly acidic or highly alkaline concentrations. pH, Nominal discharge range is 6.70 - 8.40 pH units. (Actual discharge limit is field programmable.)

Effluent Monitoring: As mandated by the local controlling authority the effluent quality must be continuously monitored. A two pen recorder is to be used to monitor effluent flow rate and pH. The recorder is to be equipped with a flow totalizer. Any effluent pH deviations will trigger an alarm and system discharge will be halted.

Utilities, Weight, Dimensions:

The system is supplied as a completely fabricated 'turnkey' package. Therefore all devices are wired and plumbed upon shipping. There is a single electrical connection point for incoming power, no further terminations are required. The disconnect on the MCP provides OSHA Lock Out / Tag Out and NFPA 79 compliance. Likewise for air, only one termination point is provided and required and a valve is supplied for OSHA LOTO.. The actual air flow requirements are quite low.

Electrical: 480VAC, 3phase, 60hz, 30 amp. Disconnect not required, provided on MCP.

Air: Less than 2 SCFM @ 80 PSIG. No special requirements for air quality.

Dimensions: 8' x 16' x 8'(h). Access to the front of the skid and the both sides is required for ease of service.

Weight: Approx. 3,400 lbs. dry. (not inc. shipping crate).


Skid: A steel skid is provided for supporting the entire system. The skid features a welded 6' Steel 'C' channel frame, a 1/4' steel deck plate, and a 1-1/2' box tube frame. Pipe and conduit supports are provided by heavy duty kindorf rails. The entire skid is bead blasted, primed, and coated with a 2 part epoxy finish for corrosion resistance. The skid color is normally OSHA Safety Blue unless otherwise specified.

Containment Pan: A Polypropylene (PP) containment / drip pan is provided for insulating the steel skid from leaking or spilled corrosive fluids and for containment of leaks. A floor drain is provided for draining the containment pan to a sump. The pan is fabricated from 1/2' PP and features 6' high walls.

Treatment Tank: The treatment tanks are custom fabricated PP tanks with 3/4' walls, and 3/4' base and cover, with a volume of 950 gallons (nominal 800 gals.) each. The tanks are supplied with a 2' gasketed lip for sealing the cover. A reinforcement rib around the perimeter of the tanks provides additional wall support. This ribs are fabricated from 4' Steel 'C' channel and are epoxy coated and encapsulated in PP. The tanks are designed for fluids with a s.g. of up to 1.9 with a safety factor of 2:1. Destructive burst testing has shown that tanks of this construction often have an ultimate load safety factor exceeding 3:1. If positive ventilation is used the tank is rated to +/- 20' w.c. The tank top is reinforced and gasketed. The top will support all mounted equipment and the weight of one 200lb. man without significant deflection.

Reagent Storage Tanks: Rotationally molded PE tanks with a fluid rating of 1.9 s.g. Tank volumes are 105 gallons each. One tank is provided for acid storage and one for caustic storage. The tanks are supplied with custom fabricated gasketed covers.

Piping: All recirculation, transfer and discharge lines are fabricated from solvent welded CPVC SCH 80 pipe. Threaded fittings are not used unless absolutely necessary. All reagent delivery lines are flexible PE tube double contained within a clear flexible PVC hose, clamped at each end to seal leaks.

Valves: All ball valves are true union field serviceable valves. All diaphragm valves are flange mounted. Elastomers are EPDM and Teflon except on concentrated acid lines where the elastomers are Viton and / or Teflon.

Electrical: All enclosures are NEMA 4X, where metallic enclosures are used they are provided with epoxy or polyester finishes for corrosion resistance. All conduit is plastic coated where possible. Low voltage 24VDC is used throughout to minimize service personnel exposure to high voltage. All systems are NFPA 79 compliant and UL508 listed.

Process Description:

The system is designed as a duplex batch treatment system designed to accept batches ranging in volume from 200 to 1,900 gallons. In order to allow for continuous flow to the system a first stage equalization stage (not shown in the picture) is used. A continuous output bubbler level sensor is used in both treatment tanks as well as in the equalization tank. A Programmable Logic Controller (PLC) within the Main Control Panel (MCP) monitors the equalization tank level. When the level rises above the 40% full mark a pair of transfer pumps are started. If the treatment tank is empty the equalization system automatically transfers a batch of up to 1,900 gallons (if it is available) to the treatment tanks. Once the treatment tanks fill to the high level the transfer from the equalization tank stops. The treatment tanks then treat the tank contents using 'Optimized Batch Treatment' technology developed by Digital Analysis. For additional information on 'Optimization Technology' contact us and request our technical brief on this subject. Once the treatment tanks contents are within the acceptable discharge range and meet all discharge criteria then discharge commences. When the treatment tanks descends to the 10% full level transfer from the first stage equalization resumes and the process repeats. Each system operates independently of one another. One tank can be filling while the other is treating and discharging. Or, both can be filling at the same time. One system can be shut down completely for service while the other continues to run.

Bulk Reagent Assist.

In a well designed system one of the primary factors limiting system throughput will be treatment chemical delivery rate. This is due to the tremendous turndown ratio that the chemical delivery device (i.e. metering pump, control valve, etc.) must be capable of. Most valves are capable of a turndown ratio of 10:1, while metering pumps are usually capable of 100:1. A pH adjustment system capable of efficiently handling concentrated discharges of acidic or alkaline effluents demand a chemical delivery ratio of 10,000:1. This simply is not possible with any one device. Our answer to this is utilizing a second pump at each point bulk chemical delivery is required. This bulk assist pump is controlled with a logarithmically responding algorithm (to emulate a pH titration curve) similar to the metering pumps control. The bulk assist pumps typically have an output that is 10 to 20 times greater than the metering pump. The bulk pump is used in conjunction with the metering pump. Treatment times for concentrated batches can be dramatically reduced thereby increasing system throughput.


A system of this design architecture is very versatile in that it can handle large flows when the influent chemistry is mild and can handle very concentrated effluent streams and accidental spills. This system is normally used in applications that can see widely varying flows and widely varying influent chemistries. For flows from 1GPM up to 60 GPM our prepackaged pHASE line of equipment usually perform just fine. For higher flows, or effluent streams with the potential of high volume, highly concentrated discharges then a custom fabricated system as depicted here is required. Flows up to 200 GPM can be handled with skidded systems such as this unit.

Additional Information:

For specific equipment information contact us directly. We can provide the specifying engineer with a formatted specification package that thoroughly describes any of our systems for bidding purposes. This includes detailed drawings, and detailed equipment specifications.

Digital Analysis Corp.
Digital Analysis Corp.
PO Box 95, 716 Visions Drive
Skaneateles ,  NY 13152


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