The reasons for the breaking up of the sludge by the manufacturer of the broken emulsion

Source: http://www.cngzet.com release date: 2015-10-20

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Introduction

In the process of treating wastewater by activated sludge process, there are many reasons that can lead to the inhibition of the activity of activated sludge, which result in the change of the nature of microorganism and the removal rate of organic substrate. Excess growth of some microorganisms can form foam or scum, runtime mechanical stress force, coerced bubble will reduce float float away the proportion of activated sludge, which not only increased the effluent suspended solids, and reduce the activity and quantity of activated sludge in bioreactor systems. On the basis of reading a large number of domestic and foreign literature, the reasons for the inhibition of the activity of activated sludge and the reasons for the rise, the method and the control technology are discussed in this paper.

One, the main factors that cause the activated sludge floating:

1, water quality

(1) surfactant and excess grease compounds

This type of material can affect the stability and permeability of the cell membrane, so that some of the essential components of the cell loss and lead to microbial growth arrest and death. When the aeration tank in the water with a great deal of this kind of material, will produce a large number of foam, these bubbles easily agglomeration in zoogloea, the proportion of activated sludge reduce float. In addition, when in water containing oil is too high, after aeration and mixing, the oil will agglomeration in zoogloea surface, hypoxic cell death, resulted in decrease of specific gravity and buoyancy.

(2) PH shocks

Too high or too low pH will affect the activated sludge microbial extracellular enzymes and exist in cytoplasm and cell wall enzyme catalysis, and microorganisms on nutrient absorption. When the continuous flow aeration tank in pH < 4.0 or pH > 11.0, in most cases in activated sludge microbial activity inhibited, or loss of activity, and even death, so that the floating sludge.

(3) the effect of salt content

The influence of alkalinity on the activated sludge can not be eliminated by the adjustment of PH. The alkaline water PH, although neutralizing the alkaline substances, but produced a salt. The osmotic pressure of salt solution is also different, and osmotic pressure is one of the important factors that affect the survival of microorganisms. If the solution of the microorganism is in a sudden change, it will lead to the death of microbial cells.

(4) water temperature

The microorganism suitable for the active sludge is suitable for the temperature range of 15 to 35, and more than 45 of the activated sludge can cause most of the microorganisms in the activated sludge to float up (except for a long period of domestication or special microorganisms). In addition, the SBR process determination of temperature effects on intracellular enzyme activity test also found that temperature in 20, 30, 40 DEG C, the enzyme activity of better than 50 DEG C, enzyme activity decreased significantly.

(5) the toxic substrate

The substrates of the aerobic activated sludge microorganism are mainly including: high content of COD, organic compounds (phenol and its derivatives, alcohols, aldehydes and some organic acids), sulfides, heavy metals, etc..

High substrate concentrations can form stable compounds in the center of cell enzyme activities, which can not be close to the substrate, and can not be degraded, and even cause cell death.

After entering the cell, the heavy metal ions are mainly associated with the -SH binding to the enzyme or protein, which causes the inactivation or denaturation. Trace amounts of heavy metal ions can also accumulate in the cell eventually to the toxic effects of microorganisms (micro action).

The most common halide is iodine and chlorine, iodine is not reversible with the bacterial protein (or) the enzyme tyrosine to generate two iodine tyrosine, so that the bacteria inactivation. Chlorine and hydration of hypochlorite, the decomposition of strong oxidizing agent. And the organic matter in the waste water, the manufacturer of the organic matter of the broken emulsion can be tamed and can degrade the organic poison.

2, process operation

(1) excessive aeration

Microorganisms in the starvation state caused by their oxidation into the aging period, the pool of DO rise; or due to poor sludge activity, aeration impeller line speed is too high, oxygen too much, in short, DO rise, the short term sludge activity is good, because the fast metabolism, organic matter decomposition is fast, but time a long time, the sludge was beaten and light and broken (but no air bubbles), like the fog covered with the flow of the surface, with the flow of water. This kind of sludge color is light, the activity difference, the oxygen consumption rate is decreased, the sludge volume and the sludge index increase, the treatment effect is obviously decreased.

(2) the rise of sludge caused by hypoxia

The sludge is gray, and if the oxygen is too long, it is black and often with small bubbles.

(3) the rise of sludge caused by denitrification

When the content of organic ammonia in wastewater is high or ammonia nitrogen is high, it can be oxidized to NO3- by nitrate and nitrite under suitable conditions, such as the two sedimentation tank or the residence time is too long, the NO3- generated by N2 reduction can be activated by activated sludge, which makes the activated sludge float up.

(4) the return flow is too large to cause the sludge to float.

Back to the sudden flow rate increase will make gas and water separation is not complete, the bubbles in the aeration tank to the floating region precipitation, the sludge is granular, the same color, turned direction is from the wall of the diversion area straight to the settling zone wall into turbulent flip.

(5) two sludge floating in the bottom of the sink

If the two sink the pond sediment produced by fermentation, CO2 and H2 also agglomerated in activated sludge, the sludge reduced the proportion of floating. Sludge produced by the decay of H2S, CH4 after the surface, the first is a small bubble escape surface, followed by a black sludge floating.

2, the excessive growth of activated sludge filamentous bacteria and the control of sludge floating

(1) temperature and load

The optimal growth conditions of the strains were 12----15, and the sludge was negative.