manure processing to reusable water using constructed wetlands meers e., michels e., march 8, 2011
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Manure processing to reusable water using constructed wetlands
Meers E., Michels E., March 8, 2011
Presentation outline
I. General introductionmanure excesses & manure treatment
II. Treatment to dischargeable water using constructed wetlands as a tertiairy step
II. Project overviewre-use of treated effluents as secondary water resource
I. General Introduction
Exceedance over EU Nitrate directive% in 2003-2004% in 2004-2005% in 2005-2006
Manure excess on soil balance
The Flanders situation
Intensive industrial farmingresults in localized nutrient (N,P)excesses at a regional level.
Similar situations in US (NC),France (Bretagne), Netherlands,Germany (Nord Westfalen), Italy,
Animal manure
Solid fraction
Liquid fraction
Physical separation Composting
Soil enhancer
Nutrient reduction by biological treatment
Manure processing
Fertilizer
Spreading over land
Animal manure
Solid fraction
Liquid fraction
Physical separation Composting
Soil enhancer
Nutrient reduction by biological treatment
Dischargeablewater
Constructed wetlands
Manure processing
Fertilizer
Spreading over land
Cascade of plant- & microbial based processes
Constructed wetlands
Rich diversity of plant species and substrates
Constructed wetlands
Constructed wetlands
“Intelligent design”: control in function of crucial monitoring parameters, feed forward & feedback loops
Cost per m3
‣Constructed wetlands were designed as an alternative for spreading manure
‧Surface: – In general: 1 m² / 1 m³ manure per year (~ 1 ha for 10.000 pigs)
– In practice: > 1 m² / 1 m³ manure
‧Cost (current systems): – 3,5-4,5 €/m³ (incl. operational and investment cost, period 10 year)
– After depreciation (10 years): 2,5-3,0 €/m³
‧Various additional break-throughs pending with impact on :
capacity (m3/m2.j) and hence cost per m3
II. Treatment to dischargeable water
Constructed wetlands
< 15 mg/l total nitrogen
< 2 mg/l totaal phosphor
< 125 mg/l COD
300 mg/l total nitrogen
250 mg/l total phosphor
3000 mg/l COD
Liquid fraction after biology Effluent Constructed Wetlands
Constructed wetlands
VLAREM standard
N content
environmental quality standard
III. Project overview: water re-use
Animal manure
Liquid fraction
Physical separation
Nutrient reduction by biological treatment
Dischargeablewater
Constructed wetlands
Water scarcity & water re-use
‣sufficient water supply is one of the most important environmental and economical challenges in agriculture in the near future
‣use of purified water on the farm is scarce
‣is reuse of end effluent of constructed wetlands an option?
Project
5 different CW locations, monthly sampling
physico-chemical parameters (non-limitative list)SS EC pH Ptot ortho-P NTU hardnessNtot NO2 NO3 NH4 BOD COD CaMg K Na F Cl SO4 AlCd Cu Fe Mn Ni Pb ZnCo Cr
bacteriological parametersC. perfringens Enterococci total Coliforms Salmonella E. coli colony count
(37°C)colony count (22°C) spores sulfite red. Clostridia
reuse options (high & low grade)drinking water live stock cleaning waterirrigation cooling water
ICH – 0,5 ha
PI – 1 ha
LA – 0,5 ha
GI – 3 ha
WVL– 3 ha
Wetland areaPrim. & Sec. Manure treatment
Pig farm
Results- compared to pig drinking water
Overall excellent results
Problem parameters
Location
Ex. Other spore elements: mainly below DL
Total nitrogen
VLAREM (15 mg/l)
No criteria for drinking or irrigation water
Nto
t m
g/l
Location
NitrateN
tot
mg
/l
Location
NO
3 m
g/l
Drinking water (taste)
pig: 100 mg/l
≠appl. Irrigation, process-, cooling- & cleaning water : -
algal bloom, leaching
Total phosphorus
VLAREM (2 mg/l)
No criterium for drinking water
essential element, non toxic, eutrofication pipes
Intensive agri- & horticulture: 15 mg/l
algal bloom storage
Process-, cooling- & cleaning water: -
eutroficationLocation
P (
mg
/l)
Total colony count (37°C)
Time
Cfu
/ml
Criterium drinking waterpig: 100.000 cfu/ml
Hardness
Location
Ha
rdn
ess
(D
°H)
Drinking water
pig: 20 D°H
≠appl. irrigation
21,5 D°H
Risk clogging
Cool- & cleaning water
salt deposit upon heating, ex. cooling greenhouse
Iron content
Variability in location
Drinking water pig: 0,5 mg/l
taste, smell, clogging
Irrigation: 0,5-15 mg/l
+: grassland, vegetables, green house farming, cultivation trees
-: open-air culture, intensive agri- & horticulture, substrate culture
Rust deposit
Ground water in Western Flanders: up to 4 mg/l
Iron removal necessary
-:
Location
Fe
(m
g/l)
Spores sulfite reducing Clostridia
Time
Cfu
/ 1
00
ml
Criterium drinking waterpig: 0 cfu/ 100 ml
Conclusions
‣preliminary results indicate that effluent quality scores better than initially anticipated, both for the bacteriological as well as the physicochemical parameters.
‣even for high grade applications constraints for reuse were limited to parameters which are easy to address using simple polishing steps.
‣we expect that reuse of constructed wetland effluent in various applications will have important economical and environmental benefits.
On site polishing
Future perspectives
Biodiversity
Biomass for energy
Algae production
Aquaculture
Contact
‣even for high grade applications constraints for reuse were limited to parameters which are easy to address using simple polishing steps.
‣we expect that reuse of constructed wetland effluent in various applications will have important economical and environmental benefits.
Prof. dr. ir. Erik Meers
(e-mail): erik.meers@UGent.be
dr. ir. Evi Michels
(e-mail): evi.michels@UGent.be
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