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Semi soft packing

Semi soft packing consists of three parts:single packing,plastic casing and central rope.All parts are made of low density polyethylene with good acid,alkali and aging resistance.After melting and injection molding,the shape radiated from the central hole is formed,and the circular single piece is the main body of semi soft packing.The central rope passes through the central holes of each single piece in turn,and the single pieces are nested with plastic pipes to form the required length in series at a fixed distance.

Semi soft packing has special structure and hydraulic performance,with large porosity(more than 96%)and small flow resistance.When the water flows through the packing layer,it can produce obvious turbulent flow pattern,improve the contact efficiency of water and biofilm,and increase the ability to remove pollutants.The filler has certain rigidity and flexibility,and has strong ability to redistribute water and air.For the air supply of big bubbles in the air blast aeration,it has the function of multi-level and repeatedly cutting bubbles,thus improving the oxygen transfer rate.The specific surface area is large(up to 130m2/m3),which provides sufficient space for the growth of microorganisms.It has the characteristics of high mass transfer efficiency,energy saving,not easy to block,corrosion resistance and aging resistance.

Combined packing

The combination packing has the structure characteristics of soft and semi soft.The middle of the packing unit is a small semi soft packing,and the surrounding is connected with the softened fiber bundle.Most of these fillers are different in the structure of the central ring and the number of fiber bundles,mainly as follows:

1.Combined double ring packing

With the plastic ring as the skeleton,the middle is a small semi soft filler,the periphery is connected with the softened fiber bundle,and the vinylon wire is tight on the plastic ring.In the sewage,the tow is evenly dispersed,easy to hang and remove the membrane,and has good adaptability to the change of sewage concentration.

2.Combined porous ring packing

40 square holes are arranged around the plastic ring sheet,and 8 bundles of vinylon aldehyde wires are arranged around the square holes,which are radial.The fiber bundle is connected with 8 square holes,which is very firm.

The combination packing combines the advantages of soft packing easy to hang film,semi soft packing not easy to tangle and block,and overcomes the disadvantages of semi soft packing difficult to hang film,so it is widely used in contact oxidation process to treat various kinds of wastewater.

Elastic solid filler

The elastic solid filler is made of high molecular polymer and additives such as hydrophilic agent,stabilizer and adsorbent by special drawing.The surface of elastic wire has small burr to increase the specific surface area.During installation,600-1000 wires are inserted and pressed between two plastic circular plates to make the wires unfold evenly and radially,and the suspension packing is made according to different distance between the plates.The packing is made of all plastic material,which has a longer life than soft packing.When aeration,each wire vibrates continuously.Therefore,the gap of the packing is variable,not agglomerated,not blocked,and the biofilm is easy to be renewed.At present,it is widely used in the hydrolytic acidification section of the treatment process of refractory organics to improve the biodegradability of wastewater.

Suspended packing

The density of suspended packing is close to that of water,and it exists in the form of suspension in the aeration tank.The dosage(by volume)is about 20%~70%of the volume of the aeration tank.There are mainly the following suspended fillers used in the project:

1.Polyhedral hollow ball packing

In the middle part of the ball,there is a fixed ring along the whole circumference.There are 12 ball petals on the top and 12 on the bottom of the ring.The holes of the ball petals are mesh or not,and they are arranged radially along the central axis.

2.Built in floating ball packing

The packing consists of a mesh spherical shell and a built-in carrier.The shell is made of polymer by injection molding,and the spherical surface is in grid shape.The internal carrier materials include aldehyde vinylon wire and button vinylon flat wire.The former is to set a shaft rod in the shell,and there are two plastic buttons on the shaft rod,each button is fixed with 6 bundles of aldehyde vinylon wire,and the fiber wire can swing freely with the water flow;the latter is to pull the thin flat wire with polyethylene as the raw material,and then fill it into the shell in the shape of flake.The mesh pore size is moderate,which has certain mechanical strength and is not blocked by the falling biofilm.

Fillers used in biofilm

Biofilm process is a high efficiency wastewater treatment method,which has the characteristics of less sludge,no sludge bulking,better adaptability to the change of water quality and quantity of wastewater,and simple operation and management.Biofilm refers to all substances attached and fixed by certain media.In the process of biofilm attachment and fixation,a certain medium is needed to undertake and complete the fixation.This medium is called biofilm carrier,also known as carrier filler.Composite packing is the habitat of biofilm,the carrier of biofilm,and also has the function of intercepting suspended matter.