Envi Eng

Question 1

Total Solids Eqn

Answer 1

TDS + TSS
(Dissolved+Suspended)

Question 2

TDS is obtained via?

Answer 2

Evaporation (container)

Question 3

TSS is obtained via?

Answer 3

Ignition (Filter paper)

Question 4

ThOD eqn

Answer 4

Stoich conversion of sample to O2 / Volume

Question 5

air at STP

Answer 5

P= 1atm
T= 20C
V= 22.4 L

Question 6

BOD5

Answer 6

(DOi - DOf)/P ; P= Vww/Vtotal

Question 7

Seeded BOD

Answer 7

BOD5 = ([DOi-DOf]-[BOi-BOf][1-P])/P

Question 8

Ultimate BOD wrt to BOD

Answer 8

Ln = Lo-BODn

BODt= Lo(1-e^-kt)

Question 9

Ultimate BOD

Answer 9

Lt = Lo-e^-kt

Question 10

Rate constant at diff temps

Answer 10

Deg = 1.056 (T = 20-30)
1.135 (T<20)
1.047 (T>30)

Question 11

Rate Constant Formula

Answer 11

Kt = k20 (deg)^(T-20)

Question 12

DO with heat

Answer 12

([DOw][Qw]+[DOr][Qr])/(Qw+Qr)

Question 13

LO with heat

Answer 13

([LOw][Qw]+[LOr][Qr])/(Qw+Qr)

Question 14

Streeter-Phelps Eqn

Answer 14

([kdLo]/[kr-kd]) (e^-kdt-e^-krt)+(Doe^-krt)

Question 15

Deoxygenation const.

Answer 15

kd = (k)+ (V/H) (n)

Question 16

reaeration const

Answer 16

kr = 3.9 (v^0.5/h^1.5)

Question 17

n (bed coefficient) values

Answer 17

n = 0.1, stagnant
0.6, rapid

Question 18

critical time (1/tc)

Answer 18

(1/[kr-kd])(ln [kr/kd][1-[D{kr-kd}]/[kdLo])

Question 19

Critical distance (Xc)

Answer 19

Xc = (v) x(tc)

Question 20

Dmaximum requires?

Answer 20

time as critical time (tc)

Question 21

Initial Deficit

Answer 21

D = Dsaturated - DO

Question 22

Hardness of water

Answer 22

Soft (<17.61 mg/L CaCo3)
Slightly Hard ( 17.61-60 mg/L CaCo3)
Moderately Hard (60-120 mg/L CaCo3)
Hard ( 120-180 mg/L CaCo3)
Very Hard ( >180 mg/L CaCo3)