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Waste Water Treatment System

Recycling of spent washing water from cleaning of electrostatic air filters
Electrostatic  Precipitation units  applied as tunnel air  filters  is cleaned at regular intervals  by means of water containing  small concentration of a special formulated  detergent.

Spent EP cleaning water contains impurities (mainly silt and carbon particles), which is to be removed to allow re-use as EP washing medium.

Water regeneration package described below is based on well proven technology, is mechanically simple and its operation may be fully automatic performed based on remote surveillance    

Primary cleaning cycle (Step 1):
Spent washing medium is collected in buffer reservoir, hereafter termed Dirty Water Tank.

Primary cleaning cycle should be carried out immediately after EP washing is finished  in order to avoid settling  of solids in Dirty Water Tank.

Procedure:

Spent water is pumped from Dirty Water tank at design capacity (2 m3/h)  to a special formulated dual medium filter, in which 99.5% of all impurities (particles) is retained.
Filtered water is  collected in Clean Water Tank.  This water  is fit for re-use as cleaning agent.

Filter regeneration: Backfludshing
Inpurities retained during primary cleaning cycle must be removed to aviod clogging of media filter. This is obtained  by pumping clean water from clean water tank through the filter in opposite direction of the normal filtration, by which retained inpurities is flushed out of the filter. Backflush stream is collected in a settling tank where particles is allowed to settle. Estimated settling period: 3 days Settled solids is then drained off by operating the sludge pump as concentrated slurry (approx 5% by weight) for external disposal.

Secondary  Cleaning cycle  (Step 2):
Water from primary cleaning cycle still contains soluble detergents, which may cause storage problems due to bacterial activity. To avoid this, a secondary cleaning process is employed.

Procedure,  Step 2
Water stored in Clean WaterTank is recycled through 2 patented electrolysis units, where DC current produces highly reactive oxidants, which kills bacteria, destroys unwanted organics, and supplies oxygen to the water, thus, avoiding storage problems.

To keep a stored  volume of 100 m3 in good condition,  water is recycled  through a electrolysis  unit where a DC current of 200 Amperes is supplied.Treated water from Step 2 is passed through the media  filters before return to Clean water tank, this prevents any biological activity in the filter medium and ensures stable long term performance of the media filters.

Secondary cleaning cycle may be performed   at intervals determined by experience, E.G.  twice a  month.

Important note, water recycling/re-use:
The combined  application of  Step 1 and Step 2 will remove  all suspended materials and prevent biological activity during storage.

Detergents consumed in the  EP cleaning cycle will form micelles with the impurities  washed off the electrostatic panels,  these micelles is then  removed in the primary cleaning cycle (Step 1).

Excessive (un-used) detergents will remain in the treated water and may be utilized in the next EP Cleaning sequence. The amount of detergent added at each EP cleaning cycle  must be adjusted in order to stabilize the active detergent concentration over longer terms.

Water quality monitoring   
A couple of parameters should be monitored (once a month) to  detect any accumulation of unwanted dissolved components:
 
--Ph value  and chloride content
Low ph and high Chloride concentration may lead to potential corrosion problems.

--Water hardness (Ca++, Mg++)  
affects efficiency of the EP washing process and causes potential scaling problems .

In general, Ca++ and Mg++ ions will consume anionic surfactants and  silicates, thus reducing the active cleaner concentration in the wash water.

Initial water used for EP cleaning should therefore be soft water with a low chloride content.

It is recommended to install in line monitoring of ph and conductivity in Clean Water tank, which  will provide adequate information on  water quality.

General flowsheet,  Water treatment system  (Blue: Step 2)


Advantages of the CTA Waste Water Threatment System:

Saves the environment, the water is recycled and is used over and over again

Removes 100% of all pollution from the water

Safe deposit of contaminated waste

2 patented electrolysis units remove 100% of all chemicals used during washing

Compact size to simplify installation

Less installation costs, all parts integrated in one easy-to-fit module



 
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