CN115367884A

CN115367884A - River-entering front buffering system for small watershed non-point source pollution prevention and control

Info

Publication number: CN115367884A
Application number: CN202210969364.5A
Authority: CN
Inventors: 汪涛; 黄美玉; 周明华; 董志新
Original assignee: Institute of Mountain Hazards and Environment IMHE of CAS
Current assignee: Institute of Mountain Hazards and Environment IMHE of CAS
Priority date: 2022-08-12
Filing date: 2022-08-12
Publication date: 2022-11-22

Abstract

The invention discloses a buffering system before entering a river for preventing and controlling small watershed non-point source pollution, which comprises: the blocking system is used for not only blocking the escape of aquatic animals, but also blocking the escape of aquatic plants due to growth and paving the channel; the aquatic animal-plant combined system is characterized in that the aquatic plants are watery plants selected from watery foxtail algae, and the aquatic animals are selected from herbivorous fishes such as grass carps and the like and are used for absorbing nitrogen and phosphorus nutrients in runoff. The method can effectively eliminate and reduce the river load of nitrogen and phosphorus pollution of river basin non-point source, can be used for biological invasion control of the watermifoil and has certain economic benefit. The method provided by the invention intervenes through active manual measures, fully utilizes the water quality purification capacity of the watermifoil, solves the problem of malignant growth of watermifoil, and reduces the load of nitrogen and phosphorus entering a river in a small watershed.

Description

River-entering front buffering system for small watershed non-point source pollution prevention and control

Technical Field

The invention belongs to the technical field of environmental engineering, and particularly relates to a buffering system used before entering a river for preventing and treating small watershed non-point source pollution.

Background

The second national pollution source census publication shows that in 2017, the Chemical Oxygen Demand (COD), total Nitrogen (TN), and Total Phosphorus (TP) in agricultural source water pollutants account for 49.8%,46.5%, and 67.2% of the total national emissions, respectively. The agricultural source pollution is mainly non-point source pollution and has the following characteristics: the pollution point is far away and has strong concealment, the pollutant concentration is low but the total amount is large, the pollution process is uncertain and has strong randomness, the treatment process is complex and takes effect slowly. Therefore, agricultural non-point source pollution becomes an urgent problem to be solved in the ecological environment treatment process of China.

Agricultural non-point source pollution refers to pollution caused by pollutants entering a receiving water body from a non-specific region under the action of rainfall or runoff in rural life and agricultural production activities. Because the main internal driving force is hydraulic action, the migration path is mainly surface runoff, farmland drainage and underground leakage, and the corresponding pollutants are mainly soluble pesticides and nutrient salts (nitrogen, phosphorus and the like). The pollution state presents the spatial distribution characteristics of non-point sources, has obvious seasonal variation rules, and is closely related to human activities, particularly agricultural production and life.

The method utilizes ecological restoration technologies such as the pulchrous myriophyllum artificial wetland and the like to treat cultivation wastewater, domestic sewage and the like. In addition, the watery algae powder can still exert high-efficiency pollutant removal capability in the natural watery channel, and particularly aims at nutrient salts, soluble pesticides and the like contained in farmland runoff inflowing from two sides of the watery channel. Research has proved that the watery foxtail algae powder can absorb the pesticide used in agricultural activities and transform into harmless substances in vivo, so that the pesticide residue in the river can be almost ignored. However, the watery foxtail algae can occupy the whole river channel by virtue of asexual propagation and faster regeneration rate, and particularly in the area where the water surface of a shallow stream is less than 20m and the water depth is not more than 1.5m, the watery channel is blocked, so that the invasion hazards of organisms such as flood discharge, aquatic organism growth and the like are influenced. Therefore, a technical system for avoiding the social service functions of river channel flood drainage and the like threatened by the excessive growth of the watermifoil by adopting proper prevention and control measures when the water purification advantages are utilized is lacked at present.

Disclosure of Invention

In order to solve the problem of waterpollution control of watery algae, the invention provides a buffering system used for non-point source pollution control in a small watershed before entering a river, which adopts the following technical scheme:

a buffering system used for preventing and controlling small watershed non-point source pollution before entering a river comprises an aquatic plant system, an aquatic animal system and a tail end intercepting system;

the aquatic plant system comprises ulexia glauca, absorbs and assimilates soluble nitrogen and phosphorus pollutants in the rapid growth process, filters particle suspended matters by means of closely staggered stalks and root systems, and provides a colonizing place for microorganisms to construct a biofilm;

the aquatic animal system mainly comprises grass carps and is used for controlling the growth state of the aquatic plant system;

the terminal intercepting system comprises a blocking net for intercepting the aquatic plant system in a near-shore water body and culturing fish in the terminal intercepting system;

the river-entering front buffer system is distributed along with farmlands according to the current situation of a river channel and is built along the bank of the river.

Further, the aquatic plant system also comprises riparian associated vegetation.

Further, the aquatic animal system also comprises bighead carp and silver carp which are mixed to be cultured.

Further, the aquatic plant system and the aquatic animal system construct a complete food net feedback loop.

Furthermore, the blocking net is a fishing net and is fixed through a wood pile, a thick iron wire or a nylon rope.

Compared with the prior art, the invention has the following advantages:

(1) The main growth distribution area of the watermifoil is fully utilized, the watermifoil is rooted on the river bank and crawls to the center of river water, so that pollutants carried when farmland runoff on two sides flows into a river channel are effectively reduced, and the non-point source pollution treatment effect is guaranteed.

(2) The method realizes the efficient utilization of the watermifoil and the watermifoil, not only can recover and recycle nitrogen and phosphorus nutrients, improve the utilization efficiency of farmland on nitrogen, phosphorus and other fertilizers, but also realizes economic benefit and ecological benefit by using dual measures of a food chain and a physical fence of a consumer.

(3) The invention has strong operability and is beneficial to manual management and technical implementation. The three-dimensional ecological buffer system can be constructed according to the current situation of the river channel and the surrounding landscape, is mainly suitable for river reach in which the watery foxtail pulchrum grows excessively and forms dominant communities. And the later-stage system is simple to maintain, and the overall economic benefit is high.

Drawings

Fig. 1 is a conceptual diagram of the overall structure of a buffering system before entering a river for small watershed non-point source pollution control of the invention.

Fig. 2 is a layout diagram of a three-dimensional buffering system for agricultural runoff into a river according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. In particular, the embodiments described herein are merely illustrative and are not intended to be limiting.

As shown in fig. 1, the buffering system before entering the river for the small watershed non-point source pollution control of the invention mainly comprises three layers of systems: the system comprises an aquatic plant system, an aquatic animal system and a tail end intercepting system, wherein the aquatic plant system, the aquatic animal system and the tail end intercepting system are mutually fused, are distributed along with farmlands according to the current situation of a river channel and are constructed along the bank of the river. The invention makes full use of the growth distribution of watercourse sillagopus viridis, in the migration process of nitrogen and phosphorus along with agricultural runoff, the self-purification function of the plants is utilized, the removal effect is achieved, the resource utilization of nitrogen and phosphorus pollution is enhanced, and the agricultural production efficiency is improved.

The aquatic plant system mainly realizes interception and purification of nitrogen and phosphorus of farmland runoff seeds by using Pinus-Green watermifoil. The pulverous myriophyllum can absorb soluble nitrogen, phosphorus and other pollutants in the rapid growth process, and can filter particle suspended matters in the path flow by means of closely staggered stems and roots, and meanwhile, a colonized place is provided for microorganisms to construct a biomembrane, so that the activity of the microorganisms is improved, and various pollutants carried by agricultural runoff are efficiently removed.

The aquatic animal system mainly uses grass carp, and can also mixedly culture bighead carp and silver carp to achieve the effect of controlling excessive growth of watermifoil. And a complete food net feedback cycle is constructed, and the fast-growing plants such as the watermifoil are controlled in a stable growth state by using fishes to prevent the excessive growth from threatening the safety of the ecological environment in the area.

The tail end intercepting system intercepts the watery foxtail algae powder in the near-shore water body in a blocking net mode, and the watery foxtail algae powder is prevented from covering the whole water surface. The watery foxtail algae powder is limited in the coastal water area by physical measures, and meanwhile, fish is cultured in the blocking net area, so that the construction of the aquatic animal system is met, and the management of the aquatic animal system and the aquatic plants and the realization of later economic value are facilitated. On one hand, the water body is ensured to be fully exchanged, and the watery plant powder myriophyllum elatinoides is limited to occupy the whole river channel, on the other hand, the watery animals can be enclosed to harvest economic benefits, and meanwhile, the watery plants can also be subjected to harmless and recycling treatment.

Furthermore, the aquatic plant system mainly uses watery myriophyllum and the riverbank is associated with local herbs.

Further, the tail end intercepting system is composed of a fishing net far away from the river bank end.

As shown in fig. 2, by means of the current situation that the watercourse is distributed on two sides of the watercourse, pollutants such as nitrogen, phosphorus and the like carried when farmland runoff is converged into the watercourse are consumed. As shown in the plan view and the A-A section view of figure 2, the outer side barrier net is used for limiting watery myriophyllum into the coastal water area, preventing the watery myriophyllum from rapidly growing and covering the whole water surface and ensuring the water flow of the riverway to be smooth. The wooden piles, the thick iron wires, the nylon ropes and the like are used for fixing the block nets, and fries such as grass carps, bighead carps, silver carps and the like are thrown into the block nets for constructing a complete feedback cycle of an ecological system and controlling the biomass of the watermifoil within a proper range. Detail a in fig. 2 shows details of the net being bi-directionally secured by nylon rope to facilitate control of the position of the net from the bank.

In conclusion, the invention has better applicability for intercepting the pollutants flowing into the river in the agricultural and rural fields, scientific and reasonable structural mode and low management and operation cost, and can effectively block the runoff loss of nitrogen and phosphorus and reduce the load of the river. In the area where the pulchrous foxtail algae forms the dominant community, the ecological purification effect and the biological invasion prevention and control can be considered, and the popularization and application values are high.

Claims

1. A buffering system before entering a river for small watershed non-point source pollution prevention and control is characterized in that: comprises an aquatic plant system, an aquatic animal system and a terminal interception system;

the aquatic animal system comprises a grass carp for controlling the growth state of the aquatic plant system;

2. The pre-river buffer system for small watershed non-point source pollution control according to claim 1, characterized in that: the aquatic plant system also includes riparian associated vegetation.

3. The pre-river buffer system for small watershed non-point source pollution control according to claim 1, characterized in that: the aquatic animal system also comprises a polyculture bighead carp and a polyculture silver carp.

4. The pre-river buffer system for small watershed non-point source pollution control according to claim 1, characterized in that: the aquatic plant system and the aquatic animal system construct a complete food net feedback loop.

5. The pre-river buffer system for small watershed non-point source pollution control as claimed in claim 1, wherein: the blocking net is a fishing net and is fixed through a wood pile, a thick iron wire or a nylon rope.