Application of a Full-scale Constructed Wetland for Tertiary Treatment of Piggery Manure: Monitoring Results

摘要

Many industrialized regions in the world are faced with local overproductions of animal manure requiring processing in an economic sound manner. Intensive animal production in Flanders and the Netherlands has resulted in a considerable overproduction of animal manure. Spreading the excess manure over arable land has resulted in contamination and eutrophication of groundwater and surface waters. Over the last 4 years, research was conducted towards the potential of more economic constructed wetlands for the final treatment step. Although, initial results with laboratory flow field experiments were insufficient to reach stringent discharge criteria (Meers et al., Water Air Soil Pollut 160:15-26, 2005a), progressive optimisation of the tertiary treatment as well as of the preceding conditioning has resulted in a consistently performing pilot scale system (1,000 m~3 year~(-1) capacity) with effluent concentrations below the discharge criteria of 15 mg l~(-1) N, 2 mg l~(-1) P and 125 mg l~(-1) COD (chemical oxygen demand), at a cumulated cost (operational plus investment) of 3-4 E∪D m~(-3) of pre-treated pig manure. Construction of full-scale installations with annual capacity of 10,000-25,000 m~3 based on this pilot model are scheduled, with the first installation currently under way. The concept has the potential to provide a low cost, in situ treatment system allowing animal farmers to process excess animal manure themselves without the requirement of expensive ex situ treatment based on industrial scale membrane technology facilities. This paper presents the research findings of the first year of the pilot scale installation.