Lagoon System Math - Division of Water Quality
Lagoon System Math - Division of Water Quality
Lagoon System Math - Division of Water Quality
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<strong>Lagoon</strong> <strong>System</strong> <strong>Math</strong> - Practice ProblemsAnswer KeyThe <strong>Division</strong> <strong>of</strong><strong>Water</strong> <strong>Quality</strong>makes no claim as the accuracy <strong>of</strong>any answers provided herein.
WB Chapter 13 • WASTE TREATMENT PONDS 223PRACTICE PROBLEMS 13.1~ BOD Loading1. Calculate the BOD loading (lbs/day) on a pondifthe influent flow is 390,000 gpd witha BOD <strong>of</strong> 245 mg/L.Lom,~ = C6 . ~y
224 WB Chapter 13 • WASTE TREATMENI' PONDS4. The BOD concentration <strong>of</strong> the influent wastewater to a waste treatment pond is 190mg/L. Ifthe flow to the pond is 125 gpni. how maliY pounds <strong>of</strong>BOD are applied to thepond daily?
WB Chapter 13 •WASTE TREATMENI' PONDS 225PRACTICE PROBLEMS 13.2: Organic Loading Rate1. A 7.S-acre pond receives a flow <strong>of</strong> 200,000 gpd. H the influent flow has a BODcontent <strong>of</strong> 190 mg/L. what is the organic loading rate in lbslday/ac on the pond?\-ex.--d.. :Lo-J ,.,J,. =
226 WB Chapter 13 • WASTE TREATMENI' PONDS4. The maximum desired organic loading rate for a IS-acre pond is 20 lbs BOD/day/ac.If the influent flow to the pond has a BOD concentration <strong>of</strong> 187 mg/L, what is themaximum desirable MOD flow to the pond? (Round to the nearest hundredth.)0... rc,,", '= IS 0
WB Chopur 13· WASTE TREATMENT PONDS 227PRACTICE PROBLEMS 13.3: BOD Removal Efficlency1. The BOD entering a waste treatment pond is 2JJ7 mg/L.lfthe BOD in the pondeffluent is 39 mg/L, what is the BOD removal efficiency <strong>of</strong> the pond?,"'-ov+~ q \(, 1r:::. ..... V~/ ..:: ,..... • 100%e ~\ LIOI"'I(..'/ -::ANS IL. \00= 10'- 1I"2.. """'::;1 '
228 WB Chapter 13· WASTE TREATMENt PONDS4. The BOD entering a waste treatment pond is 140 mg/L. Ifthe BOD in the pondeffluent is 56 mg/L, what is the BOD removal efficiency <strong>of</strong> the pond?'Ir\ _O'J+ %. \00II-->I l.-l 0 ""C-} I L - S v WI '" I L ~/__....L. ..J~_. '00 701L.l0 VY\:1'L(,0 %ANS (PC) %\.
WB Chllpter 13· WASTETREATMENr PONDS 229PRACTICE PROBLEMS 13.4: Hydraulic Loading Rate1. A 20-acre pond receives a flow <strong>of</strong> 3.3 acre-feet/day. What is the hydraulic loading rateon the pond in inJday?QI ,,""CC\ ::;l.-O CI.(...rcFlow ~.6=c..c... ~ /c:I..""jHLQ -=\-\LR.::~\ovJc..... .... c· c....>. o~'_'21cJ" I""Lo Co. '""~ I'"\-\LQ. =- o .l-=t ''-. {'... L.O cJ..", I~/ ANSHLI'l ::: "2-,0 '''"l~I2. A IS-acre pond receives a flow <strong>of</strong> Sacre-feet/day. What is the hydraulic loading rateon the pond in inJday1= \S VI c.. t'" c::1= loUJ = S.Cle.· ~ ( dGA Io..f"Cc.•.\4LR =~\ovJ._--CAr~C--\..,....I-+L..R.:S c..c..' ?/c/'.· /I 5Go
230 WB Chapter 13· WASI'ETREATMENI' PONDS4. A waste treatment pond receives a flow <strong>of</strong> 1,680,000 gpd. If the surface area <strong>of</strong> thepond is 14 acres. what is the hydraulic loading in inJday'?o."'CC
WB ChDpter 13. WASTE TREATMENl' PONDS 231PRACTICE PROBLEMS 13.5: Population Loading and Population Equivalent1. A 4-acre wastewater pond serves a population <strong>of</strong> 1320 people. What is the populationloading on the pond?O.f'"'Cv =pl- =\>0"" •pL =2. A wastewater pond serves a population <strong>of</strong> 5460 people. Ifthe pond covers 18.5 acres,what is the population loading on the pond?o..r
232 WB Chapter 13 • WASTE TREATMENT PONDS4. A 250.000-gpd wastewater flow has a BOD content <strong>of</strong> 2160 mg/L. Using an average<strong>of</strong>0.2 Ibs BOD/day/person. what is the population equivalent <strong>of</strong> this flow?'2... e,oI 000 :;, 1..,1."'" C;:S. ~L.l ("l.' v O I'VI:JI t-) ) '- ',000,000 oj .
WB Chapter 13· WASTE TREATMENT PONDS 233PRACTICE PROBLEMS 13.6: Detention Time1. A waste treatment pond has a total volume <strong>of</strong> 17 ac-ft. If the flow to the pond i$ 0.42ac-ft/day. what is the detention time <strong>of</strong> the pond (days)?DT ::,-=+ r. c. \.1o .w. L " ... \.! ) _A'J /ANS 40. S d" l
·234 WB Chapter 13· WASTETREATMENf PONDS4. A waste treatment pond has an average length <strong>of</strong> 680 it, an average width <strong>of</strong> 420 ft,and a water depth <strong>of</strong> 4 ft If the flow to the pond is 0.47 ac-ftlday what is the detentiontime for the pond?~~C-' ~ • 1..4-20 ~u "3" S (.40