Standard Profile

The standard counterflow air stripper is designed for flows from 0–910 m³/hr (0–4000 gpm). It can remove volatile and semi-volatile organic compounds including, but not limited to, chlorinated hydrocarbons, BETX, MTBE and others. It has the lowest initial cost and operating cost of any air stripping design.

Depending on the quantity of organics stripped from the water, an integral air treatment system can be provided using our technology with vapor phase carbon, thermal/catalytic oxidizers, or other equipment for removal of the VOCs from the air.

Iron Oxidation – Aeration Systems

The iron aeration unit is designed to totally saturate the inlet water with oxygen. The discharge water is normally sent to a retention tank where final oxidation of the iron occurs.

Case Study No. 5 – pH Control in Copper Mining

High Temperature Agitated Slurry Copper Ore Mixtures

• Agitated heavy slurry mixtures are endured by the sensor by use of a strong break resistant thick-wall pH glass element (nearly unbreakable under ordinary mining slurries use)
• Build up on reference element is minimized by solid state reference system, which also allows for aggressive chemical and mechanical cleaning
• Retrofit sensor can connect to almost any existing pH Transmitter
• Advanced waterproofing assembly allows for continuous submersible installation with little or no solution intrusion onto cable from back of probe
• Unique sealing technology that is custom built and engineered for mining applications allows for continuous and aggressive dissolved ammonia gas exposure

The Problem
A mining company needed a pH sensor to monitor the extraction of the desired metals from a sulfide containing ore. The extraction involved the oxidation of the sulfides at high temperature and pressure by means of injected ammonia gas in a strong acid solution. Previously used sensors had lasted such a short period of time that the installation point of the measurement was changed so as to be farther away from the ammonia injection point. This lengthened the previous sensor's lifetime but reduced the accuracy and quality of the process control measurement resulting in lower product yields and efficiency.

The sensor required by the mining company needed to withstand (and be once again installed at) the high temperature process conditions at the ammonia injection point to provide good process control values. Initially the sensor would need to resist the dissolved sulfides in solution and later in the process the resulting mixtures of diluted strong acids. The sensor had to resist the temporarily liberated hydrogen sulfides at excess dissolved ammonia gas at high temperature and pressure. The heavy slurry solution was agitated, which can result in the breakage of the pH element. The constant build-up of the slurry on the reference and pH element caused inaccurate pH readings and required frequent cleaning and calibration. These cleanings slowed or stopped the extraction process. Previous sensors rarely lasted long enough to have cable corrosion appear to diminish sensor performance.

The Solution
The solution to this very tough measurement application was the combination of a high temperature, sulfide, acid and slurry/viscous material resistant pH element with a high temperature, dissolved ammonia gas, acid and sulfide resistant solid state triple junction reference system. A chemically and thermally resistant immersion ULTEM sensor body housing was employed. The high performance waterproofing style "C" assembly was implemented to offer maximum resistance against cable corrosion even during deep and continuous submersion installation (shown below) under aggressive conditions. The lifetime in this application was increased over five-fold and the required pH calibrations were nearly reduced to one-third of the previous frequency.

The pH Sensor Used:
Model: PNCTJHR 6031/6131/6631-3000JYC-25 pH Sensor - with Waterproofing Option "C"
Description: ¾"- 1" MNPT Immersion ULTEM Bodied Low Impedance, High Temperature, Sulfide, Dissolved Gas and Hysteresis Resistant pH Sensor with Triple Junction reference system; Integrated 3000 Balco Temperature Element and Stainless Steel Solution Ground; 25 feet cable to connect directly to Johnson Yokogawa pH Analyzer/Transmitter – with Waterproofing Option "C" (Shown Below)

Case Study No. 9 – pH Control in Nickel Mining

High Temperature Agitated Slurry Nickel Ore Mixtures & Solvent Extractions (SX)

• Agitated heavy slurry mixtures are endured by the sensor by use of a strong break resistant thick-wall
• pH glass element (nearly unbreakable in most mining slurries)
• Build up on reference element is minimized by solid state reference system, which also allows for aggressive chemical and mechanical cleaning
• Retrofit sensor can connect to almost any existing pH Transmitter
• Advanced waterproofing assembly allows for continuous submersible installation with little or no solution intrusion onto cable from back of probe
• Unique sealing technology that is custom built and engineered for mining applications allows for continuous and aggressive dissolved ammonia gas exposure
• Unique organic solvent & hydrocarbon resistant reference systems and sealing technology allow for continuous submersed sensor use with little degradation

The Problems
A nickel mining company wanted to perform pH measurement for sulfide removal by ammonia injection (leaching) and solvent extraction (SX) portions of their nickel extraction operations. The high temperature, heavy agitated slurry mixtures with the presence of dissolved hydrogen sulfide and ammonia gas is quite similar to that which is described in far greater detail in ASTI's case study # 5 problem section. The solvent extraction process utilizes significant amounts of kerosene, other hydrocarbons and solvents. These extraction agents in combination with the complex slurry ore mixture present a corrosive and aggressive process media for measurement. Previously used sensors required frequent cleaning and recalibration due to organic coating on the sensors. The need for frequent maintenance accelerated the previously used sensor's demise because the frequent removal from the process resulted in performance degradation due to repeated temperature cycling.

The Solutions
The solution to the leaching application is similar to that described in ASTI's case study # 5 solution section, except that the higher process temperatures and heavier slurry mixture necessitated the use of a thicker walled twist-lock style body from a PEEK material of construction (see further details in pH sensor used for leaching on next page of case study). In addition, a more elaborate cable isolation was required of the waterproofing assembly (Style "B" shown below) due to the deeper submersion installation. The solution to measuring pH in solvent extraction mining processes was the combination of an organic solvent, acid, sulfide and dissolved gas resistant solid state reference system and thick wall, acid, organic and dissolved gas resistant engineered pH element. The proper temperature compensation and preamplifier electronics were integrated into the sensor to allow the retrofit pH sensor to install directly onto the existing explosion proof Rosemount pH transmitter. The maintenance requirements and lifetime of the sensor exceeded the previously used models over three fold, saving operator time and reducing sensor consumption. Hydrocarbon resistant waterproofing style "E" was required to ready the sensor for submersible service.

The pH Sensor Used in Leaching:
Model: PNCTJHRGR 8141/8441/8641-3081-30 pH Sensor - with Waterproofing Option "B"
Description: 1" MNPT Twist Lock (with Tines) PEEK Bodied High Temperature, Sulfide, Dissolved Gas and Hysteresis Resistant pH Sensor with Triple Junction reference system; Integrated 100 Ohm Platinum Temperature Element; 30 feet cable to connect directly to Rosemount 3081 pH Analyzer/Transmitter – with Waterproofing Option "B" (Shown Below)

The pH Sensor Used in Solvent Extraction (SX):
Model: PNCLTS 8431/8631-2081-25 pH Sensor - with Waterproofing Option "E"
Description: 1" MNPT Twist Lock (with Tines) PEEK Bodied High Temperature, Sulfide, Dissolved Gas, Solvent and Organic Media and Hysteresis Resistant pH Sensor with Triple Junction reference system; Integrated 100 Ohm Platinum Temperature Element; 30 feet cable to connect directly to Rosemount 3081 pH Analyzer/Transmitter – with Waterproofing Option "E" Waterproofing Engineering for Solvent Extraction SX Environments (Shown Below)

Choosing the Correct pH/ORP Sensor
1. Choose a sensor body type that suits the physical parameters of the installation (refer to the Configurations Portion of pH/ORP and Ion Selective webpages).
2. Choose a sensor that suits the process application, temperature, chemistry, and physical parameters of the installation (refer to Sensor Selection Guides and call factory or local sales agent for support)
3. Choose a sensor housing material that is compatible with the process chemistry, temperature & pressure (refer to Chemical Resistance Charts as posted under the Technical Documents portion of the website).
4. Select suitable temperature compensation element, solution ground & integrated preamplifier based upon the mating pH/ORP Instrument (refer to Electrochemical Instrumentation Page & ask for factory support).
5. Specify the required cable length based upon installation location (refer to Part Numbering Guide).

* Subject to application qualification and review by an approved ASTI sales agent and/or factory. Performance guarantee is posted on the ASTI online application questionnaire page.
** See list of supported pH/ORP/ISE Instruments webpages as posted on the ASTI website.
*** Completion of Application Questionnaire form is required. Other restrictions may apply.

The Greenspan AQUALAB Water Quality Analyzers are a Cost-Effective Solution to all your Water Quality Monitoring Needs. It is configurable analyser allowing you to select the appropriate chemistry package for your application from wastewater to environmental monitoring.

AQUALAB can be configured to perform any selection of physical parameters (pH, electrical conductivity, dissolved oxygen, turbidity, temperature and oxidation reduction potential - ORP) and nutrient parameters (total reactive phosphorus, nitrate, ammonia and ammonium).

The analysers are designed to meet the analysis requirements of the user and the harsh environment of remote locations. AQUALAB offers multiple physical and chemical parameters housed in an environment controlled enclosure. Analysis parameters are housed in chemistry modules within the analysers, the configurations of the chemistry modules and analysers are:

Module Parameter

• Physicals - Electrical Conductivity, pH, Dissolved Oxygen, Oxygen Reduction Potential, Temperature, Turbidity

On board standards and dynamic calibration in association with standard laboratory methodologies ensures that AQUALAB will provide accurate and laboratory comparable data. The functionality of the AQUALAB allows for unattended operation with a minimum of field visits and the advantage that data review, system monitoring and diagnostics can all be performed via your desktop PC.