Manure processing to reusable water using constructed wetlands Meers E., Michels E., March 8, 2011

Presentation outline I. General introduction manure excesses & manure treatment II. Treatment to dischargeable water using constructed wetlands as a tertiairy step II. Project overview re-use of treated effluents as secondary water resource

I. General Introduction

Exceedance over EU Nitrate directive % in % in % in Manure excess on soil balance The Flanders situation Intensive industrial farming results 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 Dischargeable water 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

“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 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 Dischargeable water 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) SSECpH P tot ortho-PNTUhardness N tot NO 2 NO 3 NH 4 BODCODCa MgKNaFClSO 4 Al CdCuFeMnNiPb Zn CoCr  bacteriological parameters C. perfringensEnterococci total Coliforms SalmonellaE. coli colony count (37°C) colony count (22°C) spores sulfite red. Clostridia  reuse options (high & low grade) drinking water live stockcleaning water irrigationcooling water

ICH – 0,5 ha PI – 1 ha LA – 0,5 ha GI – 3 ha WVL– 3 ha Wetland area Prim. & 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 Ntot mg/l Location

Nitrate Ntot mg/l Location NO3 mg/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: -  eutrofication Location P (mg/l)

Total colony count (37°C) Time Cfu/ml Criterium drinking water pig: cfu/ml

Hardness Location Hardness (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 (mg/l)

Spores sulfite reducing Clostridia Time Cfu / 100 ml Criterium drinking water pig: 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 ( ): dr. ir. Evi Michels ( ):