Wastewater from sewage treatment plants often contains organic materials that are decomposed by microorganisms, which use oxygen in the process. (The amount of oxygen consumed by these organisms in breaking down the waste is known as the biochemical oxygen demand or BOD. A discussion of BOD and how to monitor it is included at the end of this section.) Other sources of oxygen-consuming waste include storm water runoff from farmland or urban streets, feedlots, and failing septic systems.

GDO-F07L5-34

MODEL : GDO-F07L5-34

Technical feature:

• Galvanic oxygen electrode with stable performance and reliable measuremente
• Stable zero point and small drift of the electrode
• Quick response of electrode (reaching up to T90%<2min / at 25℃)
• With the measurement range 60ppb to saturation 20ppm and the compression resistance of 3bar
• With the temperature range of 0~60℃ (suitable for steam sterilization);
• With the flow rate of 0.02m/sec

GDO-F07L5-34 溶 氧 电 极

[典 型 应 用] 广泛应用于水质处理、水文监测、废水处理、游泳池、鱼塘和化肥、化工、生物等领域的含氧量监测

[测 量 原 理] GDO-F07L5-34型氧电极是一种隔膜式极谱（clark）型传感器。由传导性电解质连接的一个阴极和一个阳极组成。 这些化学反应产生与所测量溶液中O2的分压成正比的电流。

[特 点] – 反应灵敏，稳定性好
– 无需要更换膜及电解液M/
– 适用于各种恶劣水质，膜不易损坏、抗污染

[技 术 参 数] – 测量原理：电流测量/极谱法
– 检测极限： ﹤60ppb含氧量
– 响应时间：25℃时含氧量下降90%﹤2min
- 残余电流：无氧介质中残留的室温信号﹤满度的2%
- 温度范围：测量时0～60℃
- 压力范围：0～3bar
- 电极信号：25℃时20～80nA（按客户要求定制）
- 温度补偿：热敏电阻阻值按客户要求定制
- 电极尺寸：直径33mm,长度160mm（3/4″螺纹接口），可按客户要求定制
- 电极材质：PPS
-透气膜：钢筛网增强的聚四氟乙烯及聚矽氧烷膜。

D25G-F07L5-34

Oxygen is measured in its dissolved form as dissolved oxygen (DO). If more oxygen is consumed than is produced, dissolved oxygen levels decline and some sensitive animals may move away, weaken, or die.

DO levels fluctuate seasonally and over a 24-hour period. They vary with water temperature and altitude. Cold water holds more oxygen than warm water and water holds less oxygen at higher altitudes. Thermal discharges, such as water used to cool machinery in a manufacturing plant or a power plant, raise the temperature of water and lower its oxygen content. Aquatic animals are most vulnerable to lowered DO levels in the early morning on hot summer days when stream flows are low, water temperatures are high, and aquatic plants have not been producing oxygen since sunset.

MODEL : GDO-F07L5-34

Technical feature:

• Galvanic oxygen electrode with stable performance and reliable measuremente
• Stable zero point and small drift of the electrode
• Quick response of electrode (reaching up to T90%<2min / at 25℃)
• With the measurement range 60ppb to saturation 20ppm and the compression resistance of 3bar
• With the temperature range of 0~60℃ (suitable for steam sterilization);
• With the flow rate of 0.02m/sec

[技 术 参 数] – 测量原理：电流测量/极谱法
– 检测极限： ﹤60ppb含氧量
– 响应时间：25℃时含氧量下降90%﹤2min
- 残余电流：无氧介质中残留的室温信号﹤满度的2%
- 温度范围：测量时0～60℃
- 压力范围：0～3bar
- 电极信号：25℃时20～80nA（按客户要求定制）
- 温度补偿：热敏电阻阻值按客户要求定制
- 电极尺寸：直径33mm,长度160mm（3/4″螺纹接口），可按客户要求定制
- 电极材质：PPS
-透气膜：钢筛网增强的聚四氟乙烯及聚矽氧烷膜。

D120G-F07L5-135

DO is measured either in milligrams per liter (mg/L) or “percent saturation.” Milligrams per liter is the amount of oxygen in a liter of water. Percent saturation is the amount of oxygen in a liter of water relative to the total amount of oxygen that the water can hold at that temperature.

In contrast to lakes, where DO levels are most likely to vary vertically in the water column, the DO in rivers and streams changes more horizontally along the course of the waterway. This is especially true in smaller, shallower streams. In larger, deeper rivers, some vertical stratification of dissolved oxygen might occur. The DO levels in and below riffle areas, waterfalls, or dam spillways are typically higher than those in pools and slower-moving stretches. If you wanted to measure the effect of a dam, it would be important to sample for DO behind the dam, immediately below the spillway, and upstream of the dam. Since DO levels are critical to fish, a good place to sample is in the pools that fish tend to favor or in the spawning areas they use.

An hourly time profile of DO levels at a sampling site is a valuable set of data because it shows the change in DO levels from the low point just before sunrise to the high point sometime in the midday. However, this might not be practical for a volunteer monitoring program. It is important to note the time of your DO sampling to help judge when in the daily cycle the data were collected.

MODEL : GDO-F07L5-34

Technical feature:

• Galvanic oxygen electrode with stable performance and reliable measuremente
• Stable zero point and small drift of the electrode
• Quick response of electrode (reaching up to T90%<2min / at 25℃)
• With the measurement range 60ppb to saturation 20ppm and the compression resistance of 3bar
• With the temperature range of 0~60℃ (suitable for steam sterilization);
• With the flow rate of 0.02m/sec

D120G-F07L5-135 溶 氧 电 极
[典 型 应 用] 广泛应用于水质处理、水文监测、废水处理、游泳池、鱼塘和化肥、化工、生物等领域的含氧量监测
[测 量 原 理] D120G-F07L5-135型氧电极是一种隔膜式极谱（clark）型传感器。由传导性电解质连接的一个阴极和一个阳极组成。
这些化学反应产生与所测量溶液中O2的分压成正比的电流。

[特 点] – 反应灵敏，稳定性好
- 无需要更换膜及电解液
- 适用于各种恶劣水质，膜不易损坏、抗污染

[技 术 参 数] – 测量原理：电流测量/极谱法
- 检测极限： ﹤60ppb含氧量
- 响应时间：25℃时含氧量下降90%﹤2min
- 残余电流：无氧介质中残留的室温信号﹤满度的2% - 温度范围：测量时0～60℃ - 压力范围：0～3bar - 电极信号：25℃时20～80nA（按客户要求定制） - 温度补偿：热敏电阻阻值按客户要求定制 - 电极尺寸：直径12mm,长度120mm（PG13.5螺纹接口），可按客户要求定制 - 电极材质：316L不锈钢壳体，POM膜帽 - 透气膜：钢筛网增强的聚四氟乙烯及聚矽氧烷膜。