Beirut Arab University

Faculty of Engineering

Department of Civil and Environmental Engineering

Environmental Engineering

CVLE-354

Advanced Wastewater Treatment

Phoshorus Removal from Wastewater

Submitted by: Name ID# Seat#

Walid Soboh 201303257 B111

Amin Nofal 201301692 A44

Mohammad Hussein 201301133 B65

Husein Al-Moued 201301720 B22

Mohammed Al-Madad 201300546 A7

Submitted date: 21/4/2015.

Submitted to: Dr. Maher Kahil .

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Abstract

The motivation behind this report is to give an outline of distinctive strategies for phosphorus expulsion from city wastewater. Center is given to substance precipitation and improved organic phosphorus evacuation albeit additionally different routines are examined, in particular, nearby treatment routines and biological and regular treatment frameworks.

The essential evacuation instruments, methodology plans and treatment results are depicted. In the report, a recorded foundation is likewise given of phosphorus evacuation systems and patterns in exploration and procedure outline. Critical variables for procedure outline is thus additionally treatment necessities for different parts in the wastewater and associations with slime taking care of. The requirement for better assessment techniques for distinctive phosphorus evacuation methodologies is brought up.

Phosphorus may turn into a restricting substance later on and phosphorus spillage from stores may be a diffusive phosphorus source. This has prompted an expanded enthusiasm for phosphorus recuperation and reuse. Three primary courses are quickly examined: Change of the nature of the slime from the treatment plants, creation of distinctive items from the slop, and source partition of human squanders from dark water

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Table of Contents

*Cover page ……………………………………………………………………………………….. page1

*Abstract ………………………………………………….…………………………………………page2

*Table of Contents ………………………………………………………………………………page3

*Introduction ……..……………………………………………………………………………….page4

*Description of the Problem of the Phosphorus Removal from Wastewater

Phosphorus expulsion from wastewater …………………………………….…………page5 Phosphorus in wastewater…………………………………………………….…………page5 Phosphorus evacuation form…………………………………………………………….page6 Phosphate precipitation …………………………………………………………….pages6&7 Methods………………………………………………...…………………………………..page7 Figure(1)……………………………………………………………………………………page8

*Current Status in Lebanon ………………………………………..……………………….page9

*Conclusion …………………………………………………………………………..………..page10

*References …………………………………………………………………………….…….…page11

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I. Introduction:

Surface waters contain certain level of phosphorus in different mixes, which is an imperative constituent of living creatures. In common conditions the phosphorus fixation in water is adjusted i.e. available mass of this constituent is near to the prerequisites of the environmental framework. At the point when the information of phosphorus to water is higher than it can be acclimatized by a populace of living life forms the issue of abundance phosphorus substance happens.

The abundance substance of phosphorus in accepting waters prompts broad green growth development (eutrophication). The sensation of eutrophication generally diminishes the water quality and subsequently it may increment altogether the expense of water treatment at treatment plants for surface water. The heap of phosphorus released to accepting waters originates from different gatherings of wellsprings of which the primary sources are rural utilization of composts, local and mechanical wastewater, and barometrical testimony. Lessening of overflow from farming utilization of area and environmental statements are complex issues better understood by sparing and specialized means instead of in fact.

The subject of this presentation is the evacuation of phosphorus from wastewater on the grounds that in created areas the real phosphorus include on accepting waters originates from metropolitan wastewater various compendia, survey papers and conditions of-expressions on phosphorus evacuation in, different perspectives have been distributed before (Nesbitt 1966, Convey 1970, Jenkins et al. 1971, Hultman 1980, Marshal 1990, Sedlak 1991, Randall et al. 1992, Barker and Dold 1996#degaard 1993, Henze et al. 1995) and on substance precipitation (Hahn 1987, Hultman and Balmer 1988, Henze et al 1995). A few Nordic theses give a decent review on diverse parts of phosphorus. Evacuation (Aspegren 1995, Bratteb 1983, Carlsson 1996, Hanaeus 1991, Hellstrom Johansson 1994, Lee 1996, Lie 1996, Nilsson 1990 and Nyberg et al 19, 1996).

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II. Description of the Problem of the Phosphorus Removal From Wastewater :

1. Phosphorous expulsion from wastewater

Controlling phosphorous released from civil and modern wastewater treatment plants is a key calculate avoiding eutrophication of surface waters. Phosphorous is one of the real supplements contributing in the expanded eutrophication of lakes and regular waters. Its vicinity causes numerous water quality issues including expanded sanitization expenses, diminished recreational and preservation estimation of an impoundments, loss of animals and the conceivable deadly impact of algal poisons on drinking water.

Phosphate evacuation is at present attained to a great extent by substance precipitation, which is extravagant and causes an increment of slop volume by up to an option is the natural phosphate evacuation (BPR 40%).

2. Phosphorus in wastewater

Civil wastewaters may contain from 5 to 20 mg/l of aggregate phosphorous, of which 1-5 mg/l is natural and the rest in inorganic. The individual commitment have a tendency to increment, on the grounds that phosphorous is one of the fundamental constituent of manufactured cleansers. The individual phosphorous commitment changes somewhere around 0.65 and 4.80 g/occupant every day with a normal of around 2.18 g. The standard manifestations of phosphorous found in fluid arrangements include:

Orthophosphates: accessible for organic digestion system without further breakdown

Polyphosphates: atoms with 2 or more phosphorous particles, oxygen and now and again hydrogen molecules join in a complex particle. Normally polyphosphates experience hydrolysis and return to the orthophosphate shapes. This procedure is generally moderate.

Typically auxiliary treatment can just evacuate 1-2 mg/l, so an extensive abundance of phosphorous is released in the last emanating, creating eutrophication in surface waters.

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New enactment obliges a most extreme centralization of P releases into touchy water of 2 mg/l.

3. Phosphorous evacuation forms

The expulsion of phosphorous from wastewater includes the fuse of phosphate into TSS and the consequent expulsion from these solids. Phosphorous can be joined into either organic solids (e.g. micro creatures) or concoction hastens.

4. Phosphate Precipitation

Concoction precipitation is utilized to evacuate the inorganic manifestations of phosphate by the expansion of a coagulant and a blending of wastewater and coagulant. The multivalent metal particles most regularly utilized are calcium, aluminum and iron.

Calcium: It is typically included the type of lime Ca(OH)2. It responds with the regular alkalinity in the wastewater to deliver calcium carbonate, which is essentially in charge of improving SS evacuation.

Ca (HCO3)2 + Ca (OH) 2 à 2CaCO3 ↓+ 2H2O

As the pH estimation of the wastewater increments past around 10, abundance calcium particles will then respond with the phosphate, to accelerate in hydroxyl apatite:

10 Ca2+ + 6 PO43- + 2 OH- ↔ Ca10(PO4)*6(OH)2 ↓

Since the response is between the lime and the alkalinity of the wastewater, the amount needed will be, all in all, free of the measure of phosphate present. It will depend principally on the alkalinity of the wastewater. The lime measurements needed can be approximated at 1.5 times the alkalinity as CaCO3. Balance may be obliged to diminish pH before ensuing treatment or transfer. Recarbonation with carbon dioxide (CO2) is utilized to bring down the pH esteem.

Aluminum and Iron:

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Alum or hydrated aluminum sulfate is broadly utilized hastening phosphates and aluminum phosphates (AlPO4). The fundamental response is:

Al3+ + HnPO43-n ↔ AlPO4 + Hn+

This response is misleadingly straightforward and must be considered in light of the numerous contending responses and their related harmony constants and the impacts of alkalinity, pH, follow components found in wastewater. The dose rate needed is a component of the phosphorous evacuation needed. The productivity of coagulation falls as the convergence of phosphorous abatements. By and by, a 80-90% evacuation rate is attained to at coagulant measurements rates somewhere around 50 and 200 mg/l. Doses are for the most part settled on the premise of seat scale tests and once in a while by full-scale tests, particularly if polymers are utilized. Aluminum coagulants can unfavorably influence the microbial populace in initiated muck, particularly protozoa and rotifers, at measurement rates higher than 150 mg/l. However this does not influence much either BOD or TSS evacuation, as the elucidation capacity of protozoa and rotifers is generally remunerated by the upgraded evacuation of SS by concoction precipitation.

Ferric chloride or sulfate and ferrous sulfate likewise know as copperas, are all generally utilized for phosphorous evacuation, despite the fact that the real responses are not completely caught on. The fundamental response is:

Fe3+ + HnPO43-n ↔ FePO4 + Hn

Ferric particles consolidate to frame ferric phosphate. They respond gradually with the regular alkalinity thus a coagulant help, for example, lime, and is regularly add to bring the pH up keeping in mind the end goal to improve the coagulation.

5. Methods

a. The primary phosphate evacuation methodologies are (see picture beneath): b. Treatment of crude/essential wastewater c. Treatment of last emanating of organic plants (post precipitation)d. Treatment contemporary to the optional biologic response (co-precipitation).

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III. Current Status in Lebanon : Organic phosphorus evacuation depends on phosphorus uptake by oxygen consuming heterotrophs equipped for putting away orthophosphate in abundance of their natural development prerequisites. The treatment procedure intended to advance the development of these organic entities, known as phosphate-aggregating life forms (PAOs) in blended alcohol (WEF and ASCE/EWRI, 2006). Under anaerobic conditions, PAOs change over promptly accessible natural matter [e.g., unstable unsaturated fats (VFAs)] to carbon mixes called polyhydroxyalkanoates (PHAs). PAOs use vitality produced through the breakdown of polyphosphate atoms to make PHAs. This breakdown brings about the arrival of phosphorus (WEF and ASCE/EWRI, 2006). Under ensuing high-impact conditions in the treatment process, PAOs utilize the put away PHAs as vitality to take up the phosphorus that was discharged in the anaerobic zone, and in addition any extra phosphate display in the wastewater. Notwithstanding diminishing the phosphate focus, the methodology recharges the polyphosphate pool in the arrival ooze so that the procedure can be rehashed (Jeyanayagam, 2005).

Phosphorus can likewise be expelled from wastewater through substance precipitation. Synthetic precipitation basically utilizes aluminum and iron coagulants or lime to frame concoction flocks with phosphorus. These flocks are then settled out to expel phosphorus from the wastewater (Viessman and Sledge, 1998). In any case, contrasted with organic evacuation of phosphorus, synthetic courses of action have higher working expenses, create more muck, and result in included chemicals in slime (Metcalf and Vortex, 2003). At the point when Total Phasphate levels near to 0.1 mg/L are required, a mix of natural and compound courses of action may be less exorbitant than either prepare without anyone else's input.

Zahle wastewater treatment plant was composed utilizing this innovation to accomplish organic phosphorus evacuation, where the principle playing point of this methodology is the huge lessening of reagent utilization. As the natural phosphorus evacuation proficiency depends specifically on surplus biomass generation, essential sedimentation is not gave upstream of the anaerobic tanks. Without essential sedimentation, enacted slop needs to treat higher contamination loads. Subsequently, natural muck creation is expanded. By this implies, a greater amount of phosphorus is commonly removed from the standard. Besides, everything of promptly biodegradable (dissolvable) substrate gave by crude water is accessible at the gulf of anaerobic zone, which additionally could altogether, enhances Bio- DeP effectiveness.

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IV. Conclusion:

Phosphorus should be eliminated from wastewater since large concentration generate an eutrophication effect and rapidly deteriorating water quality. Limnologists begin to warn about the eutrophication burden of daystar compounds at the end of the 1950's due to the increased employment of phosphate containing detergents.

Main sources of phosphorus compounds in sewage come from human excreta and detergents. A minor part of phosphorus in municipal wastewater is due to food additives, corrosion inhibitors, and industrial sources.

Application of chemical precipitation for phosphorus removal started around 1960 and chemical precipitation with the use of aluminum and iron salts and lime was the chosen technology.

Chemical precipitation is today a well established technology for phosphorus removal from municipal wastewaters.

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References

Journal Articles

Arvin E. (1985) Biological removal of phosphorus from wastewater. CRC CriticalReview in Environmental Control vol.15, (1), pp. 25-64.

Brattebø H. (1983) Phosphorus removal from wastewater by fixed-bed adsorption ongranular activated alumina. Division of Hydraulic & Sanitary Engineering, TheUniversity of Trondheim, the Norwegian Institute of Technology (Doctorate thesis).

Books

Bundgaard E. and Tholander B. (1978) Simultaneous precipitation of phosphorus,BOD removal, nitrification and denitrification in full scale practice Progress WaterTech. vol.10, (1/2), pp.163-171.

Comeau Y., Rabionowitz B., Hall K.J. and Oldham W.K. (1987) Phosphate releaseand uptake in enhanced biological phosphorus removal from wastewater. Journal ofWater Poll. Contr. Fed. vol.59, (7) pp.707-715.

Websites

http://www.epa.gov/region10/pdf/tmdl/awt_report.pdf

http://www.desware.net/sample-chapters/d13/e6-144-10.pdf

http://www.sciencedaily.com/releases/2012/08/120815112243.htm

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