Background technology
In recent years, because the continuous growth of population and developing rapidly of industrial or agricultural, the sewage that is rich in nutritive substance in a large number directly enters in the various water bodys without any processing, thereby causes the eutrophication process to be quickened.The eutrophication of lake and reservoir has become an outstanding environmental problem of China.
The comprehensive controlling way and the countermeasure of eutrophication in recent years can reduce: physical method, chemical process and biology/ecological method.For physics method and chemical method, the proposition of biology/ecological reestablishment is later, only is inchoate before nearly more than ten years, and aquatic plant purification technology especially wherein is just to begin in recent years to obtain to pay attention to.The great advantage of aquatic plant purification technology is can be by absorption, the adsorption of plant, and the nutritive substance in degraded, the conversion water body is removed away organic pollutant by the form of results plant materials then from the system of waters.Therefore, this method usually can reach the effect for the treatment of both principal and secondary aspect of disease.
The work that utilizes the aquatic plant purification technology to repair eutrophication water is carried out the several years, and existing both at home and abroad a few thing has been obtained effect preferably, but still has problems.Its key be how to select for use suitable purification plant and to results plant how to utilize.If it is improper to purify the plant selection, not only can not repair, and because the overgrowing of plant can cause secondary pollution on the contrary eutrophication water.Present existing purifying method is divided into two classes substantially: the one, and adopt aquatic macrophyte (water peanut, Herba Eichhorniae, macro etc.) to purify nitrogen-phosphorus wastewater, though decontamination effect improving is good, but because plant materials shape volume is big, root system is crisscross, be difficult in time remove with simple mechanical means, need to consume a large amount of manpowers, easily stir bed mud during removing, thereby have the secondary pollution problem; And multifilament, be of low nutritive value, palatability is poor, the danger of rich long-pending heavy metal is arranged, and is difficult to as animal-feed, can only be as the low compost of economic worth, biogas raw material, can not accomplish really that resource utilization recycles.
Another kind method is to adopt small-sized algae (chlorella, grid algae etc.) to purify nitrogen-phosphorus wastewater, but because the algae volume is too small, is difficult to reclaim fully, so still contains a large amount of algae in the water outlet, easily causes secondary pollution after entering natural water.Therefore,, not only to consider the soil removability of waterplant, also will consider that the resource utilization behind the aquatic plants growth is recycled problem simultaneously selecting waterplant to repair in the process of body eutrophication.The nutritive substance in the water body can be effectively removed in utilization, salvages easily again and can not cause secondary pollution to water body, and preferably the high waterplant of economically valuable is administered eutrophication water again, is the preferred option of repairing body eutrophication.
Summary of the invention
The objective of the invention is for overcoming above-mentioned the deficiencies in the prior art, and proposed a kind of method of the aquatic macrophyte treatment system purifying eutrophication water body that utilizes duckweed and raise together with.
Technical scheme of the present invention is: the key of waterplant treatment system be how to select for use suitable purification plant and to results plant how to utilize.Compare with waterplant Herba Eichhorniae, water peanut or small-sized algae commonly used, duckweed has equally not only that absorbed nitrogen, phosphorus ability are strong, fast growth, widespread characteristics, but also following advantage is arranged: 1) volume is moderate, easily reclaim, the mode that can take easily to add equipment for filtering water such as screen cloth on canoe is carried out mechanical harvest, save artificial, reach the unnecessary duckweed of timely results, the purpose of control overgrowing; 2) be of high nutritive value, low fiber, high protein, leaf yellow acid and lysine content are abundant, and heavy metal accumulation is low, security is good, and alternative corn soybean is as the animal-feeds (protein content of dry matter is up to more than 30%) such as high protein livestock and poultry, aquatic products of high-quality, safety; 3) duckweed can be used as medicine, and system makeup, the economic use value of its tool high added value are that other waterplant institute can not reach.Therefore, utilizing duckweed not only can carry out the degree of depth to organic pollutants such as the nitrogen in the sewage, phosphorus absorbs, purifies, duckweed after the results is recycling to a certain extent, realize recycling economy, thereby have better economic feasibility and wide application prospect, be suitable as very much the sewage purification first-selected waterplant kind that especially nitrogen-phosphorus wastewater purifies and resource utilization is recycled.The purpose of raising together with the Herba Eichhorniae water peanut in treatment system is the anti-portative power of increase system, adapting to the fluctuation of water quality, and plays and slows down the effect of stormy waves to the influence of duckweed.
Concrete technical scheme of the present invention is: a kind of method of utilizing waterplant to administer eutrophication water, it is characterized in that the aquatic macrophyte of in eutrophication water, putting duckweed in a suitable place to breed and raising together with, after absorption, absorption and the biochemical action purification by waterplant in the system of raising together with, the nitrogen in the water body, phosphorus composition and other pollution substance are removed; The aquatic macrophyte that duckweed is raised together with it is put the 70-90% that area accounts for the water surface in a suitable place to breed.
Wherein aquatic macrophyte is any one or two kinds in water peanut, the Herba Eichhorniae, puts area in a suitable place to breed and accounts for 10%~20% of the water surface; The area of putting in a suitable place to breed of duckweed accounts for 60%~70% of the water surface.The breeding density of raising together with duckweed in the system is 0.2~0.5kg/m
2, the breeding density of water peanut is 0.8~1.0kg/m
2, the breeding density of Herba Eichhorniae is 1.4~1.6kg/m
2
For the normal growth that guarantees plant and to the efficient removal of pollutent, duckweed was gathered in the crops once in per 3~15 days except that winter, harvest yield be in the treatment system its total biomass 10%~30%; The harvesting of per 5~10 days of the aquatic macrophyte of raising together with it once, the harvesting amount be in the treatment system its total biomass 20%~50%.Summer, two seasons of autumn can suitably increase results (harvesting) number of times.The suggestion of winter low temperature condition stops results (harvesting) waterplant, and takes suitable insulation measure, or before arriving in the winter time it is dragged for to the greatest extent, and reseeds cold-resistant submerged plant hornwort, utilizes its good nitrogen, phosphorus receptivity, keeps the stability of purification system.The duckweed of results can be used as livestock and poultry animal feed or other economic utilizations, also can be used for compost or produce biogas with other waterplant of raising together with.
Raise together with and establish aerating system in the system and the water in the treatment system is stirred, accelerate the degraded of pollutent, promote the absorption of plant, overcome the influence of the depth of water processing efficiency to nitrogen, phosphorus by little aeration mode intermittently.
The duckweed volume is moderate, easily reclaims, and can take the mode of additional screen cloth class equipment for filtering water on canoe to carry out mechanical harvest easily, saves manually, reaches the unnecessary duckweed of timely results, the purpose of control overgrowing.
The purpose of raising together with the Herba Eichhorniae water peanut in treatment system is the anti-portative power of increase system, adapting to the fluctuation of water quality, and plays and slows down the effect of stormy waves to the influence of duckweed.
This patent removes and is applicable to natural waters such as eutrophic lake, reservoir, river, also can be used as sanitary sewage, trade effluent, livestock and poultry, aquafarm waste water etc. through the tertiary treatment after carrying out a biological disposal upon in the conventional waste water disposal system, to remove nitrogen, phosphorus composition wherein.
Beneficial effect:
1, utilizing duckweed not only can carry out the degree of depth to organic pollutants such as the nitrogen in the sewage, phosphorus absorbs, purifies, duckweed after the results is recycling to a certain extent, realize recycling economy, thereby have better economic feasibility and wide application prospect, be suitable as very much the sewage purification first-selected waterplant kind that especially nitrogen-phosphorus wastewater purifies and resource utilization is recycled.Raising together with the Herba Eichhorniae water peanut in treatment system can increase the anti-portative power of system, adapting to the fluctuation of water quality, and plays and slows down the effect of stormy waves to the influence of duckweed.
2, this patent is simple to operate, and structure and operational and administrative expenses are low, and effect is obvious, can not cause secondary pollution, suits as novel process China's conventional waste water disposal system old technology to be undergone technological transformation.
Embodiment
Embodiment 1
This patent is to the treatment effect of pig farm, suburbs, Nanjing anaerobic digestion solution under the investigation meteorological conditions in winter (is example with Nanjing).The square synthetic glass container that it is 50cm that two length of sides are adopted in this experiment is as treatment unit, and one is used as experiment, and a usefulness compares.The pig farm anaerobic digestion solution is joined in the treatment unit, depth of water 40cm, in experimental installation, add healthy duckweed and water peanut, Herba Eichhorniae (taking from laboratory amplification culture water tank), the fresh weight dosage is respectively 75g, 25g and 40g, water surface fraction of coverage is respectively 60%, 10% and 10%, and breeding density is respectively 0.5kg/m
2, 1.0kg/m
2And 1.6kg/m
2, comparison device does not add waterplant, and two treatment unit were placed outdoor physical environment one month.Experimental result shows that experimental installation descends 54% than the comparison device chemical oxygen demand (COD), and total nitrogen descends 78%, and total phosphorus descends 75%.Although test conditions is low temperature, high ammonia nitrogen, the growth of test plant is not had a strong impact in the treatment unit, system's operational excellence.Since waterplant in the winter time cold condition down upgrowth situation and for the decontamination effect improving of waste water with respect to the whole year other meteorological conditions relatively poor, thereby the continuous operation of waterplant treatment system under annual weather condition that this experimental result can be based on duckweed provides feasibility study.
Embodiment 2
This patent is to the treatment effect of Nanjing eutrophication Black Warrior lake water under the investigation meteorological conditions in summer (is example with Nanjing).The square synthetic glass container that it is 50cm that two length of sides are adopted in this experiment is as treatment unit, and one is used as experiment, and a usefulness compares.Eutrophication Black Warrior lake water is joined in the treatment unit, and depth of water 40cm adds healthy duckweed (taking from laboratory amplification culture water tank) in experimental installation, and the fresh weight dosage is 40g, and water surface fraction of coverage is 80%, and breeding density is 0.2kg/m
2, comparison device does not add waterplant, and two treatment unit were placed outdoor physical environment one month, during per 3 days results a duckweed, harvest yield is 20% of total biomass.Experimental result shows that experimental installation descends 76% than the comparison device chemical oxygen demand (COD), and total nitrogen descends 88%, and total phosphorus descends 92%.Effect is obvious, and water body eutrophication degree reduces greatly.