طرق ازالة الفينول/السيانيد/كبريتيد الهيدروجين/النيتروجين من مياه الصرف الصناعى مقدمة من المهندسة/نورا عبد الغفار

TECHNO LAB ELBAHAA GP

Answers Of Questions About Removal Of Contaminated Items

By : Eng . Noura Abd EL-Ghaffar Awad
Introduced To : Dr.Bahaa Badr EL-Din










1) THE TYPE OF FLOCULLANTS WILL USED WITH YOUR PROCESS TO REMOVAL THE CONTAMINATED ITEMS :

Answer :

A - In case of phenol :
1- formaldehyde in addition to acidification of wastewater.(1)
The method : By reaction of the phenol with formaldehyde in an alkaline environment at 50° to 100° C. to form those phenolformaldehyde condensates which, by subsequent acidification of the waste water, precipitate in filterable, granular and no longer sticky form and can be separated.
Strong acid is used in acidification as : Hydrochloric acid, sulfuric acid or phosphoric acid, or an organic acid such as formic acid.
-pH during the treatment should be at least 11.Sufficient alkali metal hydroxide is expediently added to the water to be treated so that 1 mole of alkali metal hydroxide is present per mole of phenolic hydroxyl groups.As a rule, sodium hydroxide is used on cost ground.

2-(HRP ) horseradish peroxide and H2O2 (2).
As a function of time , phenol and H2O2 reacts with an approximately one-to-one stoichiometry, the phenol is almost completely precipitated within 10 min.The reaction is inhibited at higher concentrations of H2O2.The removal effieciency increase with an increase in the concentrations of H2O2.The removal efficiency increases with an increase in the concentration of HRP, but an increase in the time of treatment can not be used to offset the reduction in removal efficiency at low concentrations of the enzyme. One molecule of HRP is needed to remove approximately 1100 molecules of phenol when the reaction is conducted at pH 8.0 and at ambient temperature.
Note : The enzyme that is used is an oxidoreductase enzyme.

3-Bentonite.(3)
By dispersing it to the contaminated water and then adding a small cationic surfactant so as to result in flocs which are agglomerates of organobentonite and bound organic pollutants.The flocs are then removed from the solution by sedimentation.
Experimental results indicate that BTMA- bentonite displays a high affinity for phenol, under appropriate operating conditions, 90% phenol removal and nearly 100 % recovery could be achieved by the adsorption flocculation process using BTMA-bentonite.





B-In case of Nitrogen compounds : (4)
1-Alum and lime.
At high pH with an optimum pH of
2- Anionic polyacrylamide with the coagulants used: ferric sulphate, aluminium sulphate and polyaluminium chloride. (5)
The optimum speed and stirring time for the flocculation stage were ascertained along with the optimum pH and coagulant. Chemical oxygen demand (COD), biochemical oxygen demand at 5 days (BOD5) and total suspended solids (TSS) were recorded at the beginning and end of each experiment in order to monitor the process. Once the optimal conditions had been established, several parameters were measured in order to assess the coagulation–flocculation process: particle number and size, sludge volume,nitrogen compunds .Anionic polyacrylamide, when added with ferric sulphate or polyaluminium chloride led to a significant increase in the settling speed.
3- Composite bioflocculant and polymeric aluminum ferric chloride grey powder, formulated with polyglutamic acid and Ca . (6)
pH is 7, temperature is 25 ºC, stirring speed of mixing is 350 r/min, stirring time of mixing is 50 s, stirring speed of reaction is 80 r/min, and stirring time of reaction is 4 min.
4-Inorganic macromolecular compounds as represented by aluminum-iron series coagulant and synthesized organic macromolecular flocculants as represented by acrylamide polymer.
5 -Polyaluminium chloride (PAC) and polyferric sulphate (PFS) .
6- Aluminum salt and/or cationic polymer.(7)
To assess dissolved organic nitrogen (DON) removal. Coagulation with aluminum sulfate removed equal or slightly lower amounts of DON as compared to dissolved organic carbon (DOC).
C-In case of cyanide :
1-Aqueous high calcium lime slurry.(8)
The aqueous high calcium lime slurry and the portion of recycled sludge are mixed for a time to obtain a uniform mix. A solution containing iron values is added to the uniform mix. Iron cyanide compounds and a portion of the complex organic compounds are precipitated. The precipitate is flocculated and is passed to a settling tank wherein the precipitate settles out to form a high density sludge.

2- Iron, chrome, and nickel (9)
Once these complexes have formed it may be possible to break them by adding excess bleach and increasing the reaction time. This method belongs to alkaline chlorination.
3-Iron salts (III) (FeCI}; Fe2(S 04)})
Reactions of compJexing and precipitation of cyanides with iron cations (III) or (II) depending on the pH value have been compiled.



D-In case of Hydrogen Sulfide
1-Ferric Chloride Solution (10)
Reacts with dissolved sulfides in water by the following summary reaction:

(1) 2FeCl 3 + 3H2S ‡ S_ + 2FeS_ + 6HCl
Dosage Ratio - ppm FeCl 3 to ppm H2S (in solution)
Applying a dosage beyond that dose required for initial H2S removal, Ferric Chloride then reacts to form Ferric Hydroxide which is a coagulant/ flocculant. The result is enhanced settling of both the generated sulfide removal solids and other wastewater particulates in the stream. The Ferric Hydroxide formed then resides in the sludge to react with H2S that may form later on in the process. This is described in the following reaction.
2) 2Fe(OH) 3 + 3H 2S ‡ S_ + 2FeS_ + 6H2 O
OR
FeCl 2 + H2S ‡ FeS_ + 2HCl
Dosage ratio ppm FeCl2 to ppm H 2S (in solution) - 3.7:1.0
2- By use of hydrogen peroxide alone (as in the report)
The process occurs through two mechanisms:

(I) Direct oxidation of H2S to elemental sulfur
(II) Prevention of H2S formation by supplying dissolved oxygen.




















2)FROM YOUR CHOOSING PROCESS,WE NOTICE ALL OF ITS ARE IN DYE PRODUCTION LINE NOT IN THE WASTE WATER TREATMENT PLANT,SO HOW CAN WE USED YOUR SUGGETED PROCESS INSIDE THE WASTE WATER TREATMENT PLANT AND AT ANY STAGES OF TREATMENT?
Answer :

We can use same methods in any wastewater plant in any stage but it only will differs in the design of the process depending on the stage during the process (it needs adding an instrument in every stage like pump,compressor,tank …etc and this means doubling of cost) , amount of the pollutants ,conditions of the stage (e.g pH,temperature….etc) and the type of the industry itself.
In case of wastewater plants then we can make recycle for the purified water to the process but if the treatment is during any stage the recycle will be complicates limiting by how clean water we want for the process depending on the type of industry and in same time it needs more pipelines and tanks and other needed instruments so the cost will doubled.
We can also add tanks for tanking the materials that will be used during the treatment if the process will occure during the stages.

3)YOU SUGGESTED MANY PROCESS FOR REMOVAL OF CONTAMINATED ITEMS,SO WHAT THE MAIN PROCESS CAN USED FOR REMOVAL ALL OF CONTAMINATED IN ONE OR TWO STEPS

Answer :
1-Flocculation (precipitation and coagulation)
2-Solvent Extraction (liquid-liquid extraction or gas liquid extraction)



4)YOU WRITE THE ADVANTAGE AND THE DISADVANTAGES OF YOUR SUGGESTING PROCESS BUT NOT CLEAR YOUR CHOIECE FOR THE BEST PROCESS,AND SAID WHY?

Answer :
A - In case of phenol : ELMs is the best solution or by using a flocculant(as in answer of question 1)
B-In case of Nitrogen compounds : By using Break-Point Chlorination or using a flocculant (as mentioned before in answer of question 1)
C-In case of cyanide :By using alkaline chlorination or precipitation technology (flocculation as mentioned before in answer of question 1 )
D-In case of Hydrogen Sulfide :By using of iron salt( Ferric Chloride Solution Flocculant) alone or hydrogen peroxide alone.
As we noticed that the flocculation is the best one for the all contaminated chemicals as it’s so simple with the least cost and there is no need for adding of constructions.

5)PLZ,MENTIONED THE CHEMICALS USED FOR WASTE WATER TREATMENT UNIT FROMM DYES/PRINTING FACTORY

Answer :
1-Aqueous sodium hydroxide OR (HRP ) horseradish peroxide and H2O2 (In removal of phenol.)
2-Chlorine OR Alum and lime ( In removal of nitrogen compounds.)
3- By using of iron salt (Ferric Chloride Solution ) alone OR hydrogen peroxide alone.(In removal of hydrogen sulfides.)
4- Bleaching material , oxidation medium , alkali medium and chlorine OR Iron salts (III) (FeCI}; Fe2(S 04)}). (In removal of cyanide .)






References

1-http://www.freepatentsonline.com/4857207.pdf
2-http://www.springerlink.com/content/41162jl758545023/fulltext.pdf?page=1
3- http://cmbi.bjmu.edu.cn/ChinaPaper/details.asp?PubMedID=11902767
4-http://www.gfredlee.com/Nutrients/MalhotraNutrRemAlum.pdf
5- http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V74-4DNPTY3-4&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1151105431&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=6d738b24437ebd03a333d360f5af5590
6- http://www.ccsenet.org/journal/index.php/mas/article/viewFile/2394/2236
7- http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V73-4M1TST6-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1151110431&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=52f590a6219eea5677a42b3cbb5b50e6
8-http://www.freepatentsonline.com/3847807.html
9- http://ip.thomsonreuters.com/dwpi_greencodes/
10- http://www.californiawatertechnologies.com/pdf/OdorBulletin.pdf