Construction method for ecological filtration bank used for purifying agricultural runoff pollution

Abstract

The invention discloses a construction method for an ecological filtration bank used for purifying agricultural runoff pollution. According to the construction method, a novel filtration bank is constructed in an area which is located between farmland and a river and is 15 to 20 meters away from the river; i.e., herbaceous plants and shrubs with well-developed roots, great amount of growth and good absorption effects on nitrogen and phosphorus are planted in the selected area; meanwhile, water distribution ditches and water distribution grooves are arranged at the front end of the selected area, a percolating filter is constructed at the rear end of the selected area, and water collecting pipes are laid at the bottom of the percolating filter. Agricultural runoff water can be introduced to the water distribution ditches and the water distribution grooves through drainage ditches of the farmland and other naturally-formed drainage ditches at first, then is adsorbed, intercepted and absorbed by the herbaceous plants and the shrubs on the filtration bank, undergoes multilayer percolation and purification under the action of different filling materials in the percolating filter and is finally discharged into the river. The filtration bank provided by the invention has the advantages of low cost for capital construction, no need for maintenance and a better purifying effect on total phosphorus, total nitrogen, nitrate and ammonia-nitrogen in agricultural runoff pollution compared with purifying effects of traditional vegetation buffer strands; moreover, the plants planted on the ecological filtration bank exert beautifying and ornamental effects.

Description

technical field [0001] The invention relates to a construction method of an ecological filter bank for purifying farmland runoff pollution, and belongs to the technical field of environmental pollution control. Background technique [0002] In recent years, with the implementation of watershed point source pollution control projects, the contribution rate of non-point source nitrogen and phosphorus into the lake pollution load has exceeded 50%, becoming the main pollution source affecting water quality, among which the loss of nitrogen and phosphorus from farmland surface runoff plays a very important role effect. The loss of nitrogen and phosphorus in farmland surface runoff is the main cause of eutrophication in surface water, and a series of environmental and economic problems caused by it have attracted widespread attention at home and abroad. In the past 20 years, although my country has accumulated some experience in the impact of farmland nitrogen and phosphorus migr...

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Problems solved by technology

[0004] At present, a multi-layer infiltration system is also used to improve the water quality of the river. Although the multi-layer infiltration system can significantly enhance the infiltration of runoff and play a good role in purifying the infiltration runoff, it is mostly a single form of independent application. It is rarely used in the prevention and control of farmland runoff pollution

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