During the operation of urban wastewater treatment plants, operational managers can directly sense the normality of the incoming water, the proper functioning of various structures, and the stability of the treatment effects through the observation of sensory indicators. An experienced operator can often make rough judgments based on these observations, allowing for quick adjustments to operational states. The main sensory indicators include the following aspects.
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The city's wastewater treatment plant typically has fresh incoming water with a fecal yellow color. If the incoming water is black and has an especially strong odor, the wastewater is likely aged and may have been sitting in the pipes for too long. The mixed liquid in the aeration pond should have a chocolate-like color.
Color can also serve as a health indicator for sludge. A healthy aerobic active sludge should be a chocolate-brown color. Dark black sludge typically indicates insufficient aeration and the sludge is in an anaerobic state.(The state of corruption.)Abnormal colors in the aeration pond may also indicate the presence of certain colored substances.(For example, chemical dye wastewater)Enter the processing facility.
2Scent
The wastewater intake, besides the normal fecal odor, occasionally emits a smell of rotten eggs near the collection wells, caused by a small amount of chemical gases produced due to the decomposition of wastewater within the pipes. The smell can also indicate whether the wastewater treatment plant is operating normally.
Wastewater treatment plants should not produce讨厌odors. Samples of well-mixed liquid collected from the aeration pond should have a slight musty smell. Once the sludge odor turns to a putrid smell, the sludge appears very dark in color, and emits an egg-like stench. If there are any other pungent, intolerable odors, it indicates the presence of industrial wastewater.
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Foams are divided into two types: chemical foam and biological foam. Chemical foam is formed by detergents in wastewater under the stirring and blowing action during aeration. During the early stages of activated sludge cultivation, there is a significant amount of chemical foam, which sometimes piles up into towering white foam mountains several meters high on the surface of the aeration tank.
During routine operations, if white, foamy waves are observed in the aeration tank, the discharge of excess sludge should be reduced. Dark, thick foam indicates aged sludge and an increase in excess sludge discharge is recommended. Brown biological foam can accumulate high in the aeration tank and be carried away with the flow into the secondary sedimentation tank. This could be due to a Kanoa bacterium-induced biological foam, usually caused by a high content of oils and fats in the influent water, such as hotel wastewater.
4Bubble
Bubbles appearing in the secondary sedimentation tank indicate that the sludge retention time is too long; the sludge return rate should be increased. If the sludge layer in the sedimentation tank is too thick, the bottom sludge will be in an anaerobic state.
These gases escape from the water surface in the form of bubbles. As the bubbles rise, they carry the flocs along with them, which then exit along with the effluent from the sedimentation pond, thereby causing a decline in the quality of the outflow water.
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Water temperature has a significant impact on the efficiency of aeration pond treatment. The water temperature in a wastewater treatment plant gradually changes with the seasons, with almost no variation within a day. If a significant change is observed within a single day, it should be checked whether industrial cooling water has entered. When the temperature in the aeration pond falls below...8At the moment,BOD5The removal rate is often below80%。
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Monitoring the flow state in the aeration pond can determine short-circuit conditions. A short-circuit refers to wastewater flowing directly from the inlet to the outlet, resulting in an effective retention time below the design value and reducing the treatment effectiveness.
Occasionally, the short-circuiting of wastewater flow can be identified by observing the movement of foam, suspended solids, and floating debris in the pond. Installing appropriate baffles can address this issue.
7Exposure volume size
Monitor the uniformity of aeration in the aeration pond, whether the aeration quantity fully stirs up sludge, and if there are any dead corners. In mechanical aeration, observe the size of the foam, as it indicates whether the immersion depth of the aeration pump is appropriate.
Low dissolved oxygen concentration in the aeration pond indicates that the blade immersion depth is not suitable. Attention should be paid to observing the blade immersion depth to achieve optimal aeration efficiency.
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The treated effluent from a normal wastewater treatment plant is highly transparent, with very few suspended particles, a slightly yellow hue, and no odor. During the summer, there is often a large amount of Daphnia in the secondary sedimentation tank.(Commonly known as fish worm)At this moment, water is flowing out.BOD5Perhaps3~5mg/LLeft and right.
Experienced operations managers can roughly assess the water quality with the naked eye. If the water clarity suddenly declines and contains a higher amount of suspended solids, it is crucial to immediately check if the sludge discharge is timely, whether the sludge discharge pipe is blocked, or if the peak flow is impacting the secondary sedimentation tank too heavily.
9Sediment Observation
Firstly, observe whether the activated sludge in the effluent well of the secondary sedimentation tank is continuously flowing out with a certain concentration. If wastewater is found during the sludge discharge, adjustments should be made to the opening degree of the gate valve and the control of the sludge discharge time. For the sludge thickening tank, monitor to ensure there is no large amount of sludge carried out with the overflow water.
10Observation of various traffic types
Fully utilize the relationship between measuring equipment and water levels or flow rates, firmly grasp the sizes and changes of incoming water, returning water, sediment discharge, and air pressure during the observation period.
11Touch Inspection
Touch is a critical means of inspecting the operation of a wastewater treatment plant. If the surface temperatures of the pumps, fans, and motors feel abnormally hot, they should be subjected to further inspection to prevent major accidents.
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