Final Report-dont Delete

8/17/2019 Final Report-dont Delete

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SEMINAR REPORT

ON

AERATED LAGOON

- PRESENTED BY -

MR. VIRAT V. RAJPUT

Roll No: - CE15ME06

DEPARTMENT OF TECHNOLOGY

UNIVERSITY OF PUNE

G!"#$%$&!'( P)!"-*1100+

DEPARTMENT OF TECHNOLOGY UNIVERSITY OF PUNE

G!"#$%$&!'( P)!"-*1100+.

CERTIFICATE1


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This is to certify that the Project Report entitled

“Aerated lagoons”is submitted by

r! "#RAT "! RA$P%T&

Roll No' ( )E1*E+,

Pursuin- .M.Tech (Civil & Environmental Technology)/

GUIDE HEAD OF

DEPARTMENT

DR. ASHO, MORE

Contents

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1 Introduction2 Special details3 Aerated lagoon design parameters4 Characteristics of Aerated Lagoons 5 Introduction to Facultative lagoons6 Characteristics of Facultative lagoons7 Operation and maintenance8 Limitations

1 INTRODUCTION

$ /)ll LAGOONS "-


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La-oons are deep 2aste stabili3ation ponds (li4e bodies of 2ater or

basins desi-ned to recei5e& hold& and treat 2aste2ater for a

predetermined period of time by arti6cial means of aeration!

#n the la-oon& 2aste2ater is treated throu-h a combination of

physical& biolo-ical& and chemical processes!

TYPES OF LAGOONS

Anaerobic Lagoon - These lagoons are typically 6 to 30 feet deep. They have no

aerobic zones, which may cause the production of odors. The detention time can vary

from 20 - 0 days. These systems have typically been used to treat high strength

wastewater. The low-rate anaerobic process stabilizes organic matter, converting it to

carbon dio!ide and methane. "f sulfur is present, hydrogen sulfide, an odorous

compound, may be produced. #articulate matter that does not get degraded will settle to

the bottom.

Facultative Lagoon - These lagoons have both an aerobic zone and an anaerobic zone.

They are typically $ to % feet deep, with a retention time around 2 days. &lgae thrive

in the top layer of the lagoon and supply o!ygen via photosynthesis. &eration in the top

layer can also come from surface mi!ing due to wind. &s depth increases the lagoon

gradually becomes anaerobic, with a sludge layer at the bottom. 'iodegradable organic

matter is stabilized by both the anaerobic an aerobic processes, releasing methane and

carbon dio!ide. (ince the top layer contains o!ygen, reduced compounds )e.g. *2(+ can

be o!idized before leaving, preventing the release of odors. These lagoons are also

nown as stabilization ponds.

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Aerobic Lagoon - These lagoons are designed to be completely aerobic, stabilizing

organic matter at a higher rate than the other lagoons. The mechanism for providing

o!ygen can vary greatly. "f algal photosynthesis is the only source of o!ygen, the

lagoon should allow light penetration through the entire water column. The depth

should not e!ceed feet, and the detention time should be around 0 to $0 days.

Partial-mix Aerate Lagoon - These lagoons are supplied with o!ygen by floating

surface aerators or submerged diffusers. The depth of these lagoons can be from 6 to 20

feet, with a detention time of to 20 days. The combination of a greater depth and

shorter detention time maes the land reuirement much less than the other lagoons.

*owever, the introduction of aeration devices increases the operation and maintenance

costs.

!om"letel# $ixe Aerate Lagoon% - These lagoons are used throughout developed

world, and can produce e!cellent effluent uality. They are designed and operated to

e!clude algae by completely mi!ing the solids, and therefore blocing all light. &lgae

can cause the effluent to e!ceed the total suspended solids )T((+ limit.

*


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2. SPECIAL DETAILS

D!/" 3o4 H&&o!

A pond site should be located as far as practicable from habitationor any area that may be built up 2ithin a reasonable future period&ta4in- into consideration site speci6cs such as topo-raphy&pre5ailin- 2inds& and forests! 8u9er 3ones bet2een the la-oon andresidences or similar land use should be at least ++ feet toresidential property lines& and 1+++ feet to e:istin- residencestructures!

P"&l&!7 &!'#

#f practical& ponds should be located so that local pre5ailin- 2inds 2illbe in the direction of uninhabited areas! Preference should be -i5ento sites that 2ill permit an unobstructed 2ind s2eep across thelen-th of the ponds in the direction of the local pre5ailin- 2inds!

Sur&ace Runo&&

Location of ponds in 2atersheds recei5in- si-ni6cant amounts of runo9

2ater is discoura-ed unless ade;uate pro5isions are made to di5ert storm2ater around the ponds and protect pond emban4ments from erosion!

" Tl"

The e9ect of the -round 2ater location on pond performance andconstruction must be considered!

Go)!' " Po"/&o!

Ground


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be re;uired and should be desi-ned 2ith proper consideration to 2atermo5ement throu-h the soil as appropriate!

An appro5ed system of -round 2ater monitorin- 2ells or lysimeters may bere;uired around the perimeter of the pond site to facilitate -round 2atermonitorin-! The use of 2ells and>or lysimeters 2ill be determined on a case(

by(case basis dependin- on pro:imity of 2ater supply and ma:imum -round2ater le5els! This determination 2ill be at the site appro5al phase!

A routine -round 2ater samplin- pro-ram shall be initiated prior to anddurin- the pond operation& if re;uired!

Floo'8"#

Pond sites shall not be constructed in areas subject to 0*(year ?oodin-& or

the ponds and other facilities shall be protected by di4es from the 0*(year?ood!

Po!' S$9"

The shape of all cells should be such that there are no narro2 or elon-atedportions! Round& s;uare& or rectan-ular ponds should ha5e a len-th to2idth ratio near 1'1 for complete mi: ponds! Rectan-ular ponds 2ith alen-th not e:ceedin- three times the 2idth are considered most desirable

for complete mi: aerated la-oons! @o2e5er& stabili3ation ponds should berectan-ular 2ith a len-th e:ceedin- three times the 2idth& or be baed toensure full utili3ation of the basin! No islands& peninsulas& or co5es arepermitted! Di4es should be rounded at corners to minimi3e accumulationsof ?oatin- materials! )ommon di4e construction should be considered2hene5er possible to minimi3e the len-th of e:terior di4es!

R"/&/)l&o!

Recirculation of la-oon euent may be considered! Recirculation systemsshould be desi-ned for +!* to 0!+ times the a5era-e in?uent 2aste2ater?o2 and include ?o2 measurement and control!

Flo8 M"#)"4"!

The desi-n shall include pro5isions to measure& total& and record the2aste2ater ?o2s!

B


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L""l G)7"#

Pond le5el -au-es should be located on outfall structures or be attached tostationary structures for each pond!

Po!' D"8"&!7

All ponds shall ha5e emer-ency dra2do2n pipin- to allo2 completedrainin- for maintenance!

Cucient pumps and appurtenances should be a5ailable to facilitatedrainin- of indi5idual ponds in cases 2here multiple pond systems areconstructed at the same ele5ation or for use if recirculation is desired!

Co!ol B)&l'&!7

A control buildin- for laboratory and maintenance e;uipment should bepro5ided!

G"!"l S&" R")&"4"!#

The pond area shall be enclosed 2ith an ade;uate fence to 4eep outli5estoc4 and discoura-e trespassin-& and be located so that tra5el alon-the top of the di4e by maintenance 5ehicles is not obstructed! A 5ehicleaccess -ate of 2idth sucient to accommodate mo2in- e;uipment and

maintenance 5ehicles should be pro5ided! All access -ates shall bepro5ided 2ith loc4s! )yclone(type fences& * to , feet hi-h 2ith strands ofbarbed 2ire& are desirable& 2ith appropriate 2arnin- si-ns re;uired!

Po&o! 3o Sl)'7" A//)4)l&o!

#n?uent solids& bacteria& and al-ae that settle out in the la-oons 2ill notcompletely decompose and a slud-e blan4et 2ill form! This can be aproblem if the desi-n does not include pro5isions for remo5al and disposal

of accumulated slud-e& particularly in the cases of anaerobic stabili3ationponds and aerated la-oons! The desi-n should include an estimate of therate of slud-e accumulation& fre;uency of slud-e remo5al& methods ofslud-e remo5al& and ultimate slud-e handlin- and disposal! Abandonin-and cappin- of the la-oon is an acceptable solution! @o2e5er& the desi-nlife shall be stated in the report!


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;. A""' L7oo!# D"#&7! P4""#

D"9$

Depth should be based on the type of aeration e;uipment used& heat lossconsiderations& and cost& but should be no less than B feet! #n choosin- adepth& aerator erosion protection and allo2ances for ice co5er and solids

accumulation should be considered!

I!


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the 6nal aerated cell must be free of turbulence to allo2 settlin- ofsuspended solids!

A"&o! E)&94"!

A minimum of t2o mechanical aerators or blo2ers shall be used to pro5idethe horsepo2er re;uired! At least three anchor points should be pro5idedfor each aerator! Access to aerators should be pro5ided for routinemaintenance 2hich does not a9ect mi:in- in the la-oon! Timers 2ill bere;uired!

1+


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*. CHARACTERISTICS OF AEROBIC LAGOONS

1! Dissol5ed o:y-en is present throu-hout much of the depth of aerobicla-oons!

0! They tend to be much shallo2er than other la-oons!

! They are better suited for 2arm& sunny climates& 2here they are lessli4ely to free3e!

7! @RT to 1+ days

*! CC concentration bet2een ,+ to ++m->l

,! The 8OD remo5al is of order of B* to *H

B! O:y-enation re;uirement is of order of !B to 1! 4- per 4- of 8ODremo5ed!

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'. FA!ULTATIVE AERO(I! LA)OONS

Three types of zones are present

• Aerobic *one-organisms decompose the waste present in wastewater in presence of

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• Anaerobic *one-organisms present in this zone carry out the process of decomposition

in absence of o!ygen i.e. they use the combined form of the o!ygen that is present in the

organic matter.

• Facultative *one-organisms in this zone ad5ust according to the zonal change and ad5ust

themselves according to the conditions.

*T )+Y,RAULI! RETENTION TI$E+ is higher than aerobic lagoons because time

reuires for the solids to settle and for many pathogens viruses to either die off or settle out.

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6. CHARACTERISTICS OF FACULTATIVE LAGOONS

CC concentration is ran-in- from + to 1*+ m->l

Detention time ran-es from B to 1+ days!

8OD remo5al are of order B* to F+H

O:y-enation re;uirement is about ! 4- per 4- of 8OD


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+. OPERATION AND MAINTENANCE-


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+.1 Fo ""' l7oo!

• Any earthen structures used as impoundments must be

periodically inspected! #f left unchec4ed& rodent dama-e can causese5ere 2ea4enin- of la-oon emban4ments!

• #n submer-ed di9used aeration& the routine application of @)l -as

in the system is used to dissol5e accumulated material on the

di9user units!

• The use of submer-ed perforated tubin- for di9used aeration

re;uires maintenance and cleanin- on a routine basis to maintain

desi-n aeration rates!

+.2 Fo F/)l&" L7oo!

• ost facultati5e la-oons are desi-ned to operate by -ra5ity

?o2! The system is not maintenance intensi5e and po2er

costs are minimal because pumps and other electrically

operated de5ices may not be re;uired!

•

Earthen structures used as impoundments must beinspected for rodent dama-e!


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=. L&4&&o!# 3o o$ o3 $" l7oo!#:

There are certain limitations of both of the types of la-oons 2hich

are discussed belo2(

Fo "o&/ ""' l7oo!

• Aerated la-oons may e:perience ice formation on the 2ater

surface durin- cold 2eather periods

• Reduced rates of biolo-ical acti5ity also occur durin- cold

2eather

• Iormation of ice on Iloatin- Aerators!

Fo 3/)l&" l7oo!#

• The inability of the process to meet a + m->L limit for TCC due to

the presence of al-ae in the euent!

• Odors may be a problem in the sprin- and fall durin- periods of

e:cessi5e al-al blooms and unfa5orable 2eather conditions!

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