During the operation of wastewater treatment systems, the size, shape and compactness of activated sludge flocs, as well as the proportion and growth status of zoogloeal bacteria and filamentous bacteria, can well reflect the operating condition of wastewater treatment. The structure of sludge flocs can be regarded as a barometer of system health. I. Normal Sludge Flocs — Sign of Stable Operation Characteristics of Healthy Sludge • Large floc particles with clear edges, compact and closed structure • Excellent adsorption and sedimentation performance • Flocs are framed by zoogloeal bacteria, with a small amount of filamentous bacteria interspersed; the quantity of filamentous bacteria is far less than zoogloeal bacteria • No free bacteria observed Microfauna in Normal Biological Phase In well-operated wastewater treatment facilities, the microfauna in activated sludge present typical features: • Dominated by sessile ciliates such as Vorticella, Opercularia and Epistylis • Aspidisca crawling on floc particles can be seen • A small number of free-swimming ciliates appear occasionally • Rotifers grow actively Judgment Conclusion The above biological phases indicate good sludge sedimentation and flocculation performance. Complete mud-water separation can be achieved rapidly in the secondary sedimentation tank with excellent effluent quality. It is necessary to strengthen operation management and maintain the current operating conditions continuously. II. Abnormal Sludge Flocs — Require Timely Intervention Characteristics of Abnormal Sludge • Loose floc structure and shrunk floc particle size • Poor settleability, impairing mud-water separation When abnormal floc structure occurs, a sharp increase of the following microorganisms is usually observed: • Free-swimming ciliates: Colpidium, Colpoda, Paramecium, Prorodon, Monas, etc. • Sarcodina: Amoeba, Vahlkampfia, etc. III. Two Major Causes and Countermeasures of Abnormal Flocs Cause 1: Too Low Sludge Loading Under low sludge loading conditions, the extracellular polysaccharide matrix of zoogloeal bacteria will be consumed as nutrients to sustain microbial metabolism, resulting in loose floc structure and reduced floc size. Countermeasures: Increase sludge loading by reducing sludge return flow, dosing nutrients, and shortening sludge retention time. Cause 2: Too High Sludge Loading Excessively high sludge loading provides abundant nutrients in sewage, stimulating massive growth of free bacteria. Flocculated zoogloeal bacteria tend to deflocculate into individual free bacteria to increase specific surface area with the surrounding environment, which also leads to loose sludge structure and smaller flocs. In addition, deflocculated and fine sludge particles are easily ingested by microfauna, causing their massive reproduction due to sufficient food supply. Countermeasures: Reduce sludge loading by cutting down influent flow and sludge discharge volume. IV. Quick Reference Comparison Chart 表格 Observation Index Normal State Abnormal State Floc Size Large Shrunken Floc Structure Compact and closed Loose Edge Definition Clear Blurred Ratio of Filamentous Bacteria to Zoogloeal Bacteria Filamentous bacteria far fewer than zoogloeal bacteria Imbalanced proportion Free Bacteria Absent Massive presence Dominant Microfauna Sessile ciliates, rotifers Free-swimming ciliates, Sarcodina Settling Performance Good, complete mud-water separation Poor, difficult mud-water separation Effluent Quality Clear and transparent Turbid Core Principle to Remember Changes in floc structure directly reflect excessively high or low sludge loading, serving as one of the most intuitive and rapid judgment bases in daily operation and management. Activated Sludge Biological Phase Observation Series · Part 2The next chapter will interpret the distress signals in microbial activity status. 在文章中加入一些关于絮体结构的图片 推荐一些污水处理相关的英文文章 污水处理相关的英文术语有哪些？
