are Ha ha (I745 a.l in siae,

Ponds can be born as rhey are as Wei-diner ro iau by
grisviiy llnw horn one lo lhe olher. In lhe hrsi series oi
lselllingi ponds, she sludge {wiles an ANAEROEIC
condlrion ln ihe nexl series oi ponds, some sludge
passes over and beeornes anaerobic al ihe pond base,
while his suriaee waier in the pond idue io Wind or
algnel is AEROIHC (oxygeneprodueingi The iinal
series or ponds u lolally aerobic Thus, iroui inrahe so
oullee, we have ihelcrms

. ANAEROBIC. or meiiianeproducing idigesler

sl

- FACULATIVE, or parl melhane, pail oxygen.
producing.

- AEROHIC, oroxygen.produeing pon .

Ponds ai Wembee are only an average oi i rn (3 leer)
deep, Deeper, and lhe sludge breakdown and wind
aeralion eileeis are less.

One ihoiisand lownspeople and iheir associaied
induslries rlieieioie need as liirle os :70 merrea )qm
of seiilirig pond I m deep. We eould, in iaci, achieve
ride as long“ pond (or series n! ponds) 3 m wide x so
in long, or 3 sidebyoide ponds so in ionic and 3 m
wide, or any such combinaiion We can halve ihelengsh
by doubling lhe depih lo 2 in and per a pond 3 m x 45
in long, or lreble “m depih and condense ihc pond area
reaamdeepxsmWidexJam long -digesler pond.

Such a long and numw pond is easily made reiaiiy
anaerobic by lining wales seisls ind . weighied (am
over lhe iop iwliich can be oi plaszis, meial, bulyl
rubber, or hbreglassi. Nam ihai ior ihese deeper
digesier ponds we would need roiiriifrcirliyrgiiole lhe
sludge luélng pumped bioges io sii ill, Dthzrwlse n
senies and becomes Inldw! irigiire ml

sludge is "inlvc' only in coniaci wllh Lb: Sum—Ilquld
inpuis oi rhe sewer, lhus when we siir iip m: sludge.
lhe beiier we break down lire sewage to biogas,
Almlher icriiieall beneiil in sealed and agllared
digeslers is rhar no 5(llm iorins on lhe pond suriisse,
which can slow ihe breakdown process lurlher and
sausean acid condiiion,

oi lhe ioral dissolved solids (or innuenil enlenng
such a digesier, over a pe 'od iii 20 days and wllh a
lernperaiure or zs-wc i77-lb-rl, a very high
percenlage oi ihe mass is iransierred inio mellone, a
small proporuon is also passed on io oiher ponds, some
as living cells ibacieria or algae: As melhane forms, so
lhe oxygen demand oi the eilliieni ialls; aboiii a cubic
melre oi melharie generaied removes abour m lrg oi
solids, reducing biological oxygen demand loom w
lhal exienl

in lhe digesier, 9mm. oi worm eggs are desnoyed.
as are many harmiui bacieria liseiul energy is
generalzdi and can be used or rhai loeaiion ro run a
molor ior eieclri , or to compress gas ior cooking or
machinery lor bolii, as power demands vary> nus
more. borh supplies lhe heal ior lhe digesler process,
and also compresses lhe gas ior digcsier agiiaiion, and
ior energy supply

Whal happens n lhe digesrer2 lhe marsh gas

 

 

 

 

 

 

 

mu 1.:
ANALVSIS 0F RAW SEWAGE
ANALYSIS
souns
Tum dissoived Wlds hm (rosy
lsiiooioal oxygen demand we - 5m (non)
suspended sold: lsa . dzo
Velauialiouidd lea-5w
Tomi moaniccamon lib—add
Anionic siinoelame I o e a d
NUIRIEMTS
Nilma as N mos
Nilroro as N ii i e as
Ammomn as N g-g‘z
anic ll -
mi N s - 55.2
omiepliaiphale as F 1,5 —s.n
Yaw phosphorus I 5 .9,n
Wm
Cowl! 0.09 - n45
cniomiiim o 25 70.4
Cidmlllm 0 cl 5
lion l s - 3 3
Lead 0 3 e o 4
Mon-airy am:
Moi-i o l5
zirrs a l e mi
coloun
1:: PVC}: urinal loo -:loo
9" as 1 2.u inear nlllmll
01 in. low sonsp. inbol iiom 45‘ Bu '1. oiine
volume builds up as siiidg in sohlirio ponds

 

 

 

produced, hydrogen sulphide (Hps), combines wiih any
soluble iorrns 0! heavy melals iii produce sulphides,
mind are insoluble in waiec above pi-l 7. A hole lime
can also adueve or assisi mis resull.

Hussarny lound lhai ihe iollowing iesull owned in
anaerobic ponds (see original meial conlenl, Table mi:

- Copper is removed was, 0! which 737. was re
moved anaerobically.

. Cidnullnl is removed 705., all anaerobically,

- zincis removed mews removed anaerobically.

- Nickel is removed 555.47% ambically

- bead is removed 95%,90'1, anaembioally,

r Chmnuum is removed 37%, m. amembuafly.

- iron is removed 35%, mi anaerobically, ilip m we
oi iron was removed by lhe loculaliye pond prooas,
lrul some iron was plflly dissolved in lhe aerobic pond
sgsin, toyve “1:857- quoiedl

The resulrs are ihar solids, rnelals, and disease
organisms are very greally reduced by lhe hrsl
ianaeiobiei oeoirneni oi sewage. Whal, in (ad, happens
lo the sludge: il becomes meihane in an anaerobic
shallow pond, or a deeper agilaled pond, lhe more
sludge, lhe more aclive rhe pond nus. is sei/erryiiiaied
eooiiihriiirri ioridiiiori soon esialiishes where inpur
balames gas oiiipiil ii we remove ilie sludge, ihe
process slows down or stops This is a clear case oi

175