目前，国内外对河流富营养化治理与维护的方法大致可以归类为物理法、化学法、生物-生态法等。

一、物理法

1、截污

　　截污是河流治理的一条有效的途径。目前国内受污染河流，无不源于外来污染物远远超出湖泊自身的净化能力而导致水质恶化、生态破坏，而截污则基本能够解决河流的污染之源，防止水体进一步恶化。截污作为一项有效的措施被广泛认可。

但是，河流截污工程浩大，涉及面广，包括大量管网铺设、污水厂建设、人员动迁、河流周边生态修复、工厂企业排污控制等，其巨额的工程投资、漫长的工期与复杂的工程实施，使众多的河流主管部门在一定时期内无力承担，而进展缓慢，因而当前的截污工作更多的体现为相关主管部门量力而行的治河措施之一，通常会结合其他的治理方法实施。

2、清淤

　　由于常年自然沉积，河流底部聚积了大量淤泥,富含可观的营养盐类,其释放也可能形成河流富营养化和水华暴发。将底泥从河体中移出,可减少积累在表层底泥中的营养盐，减少潜在性内部污染源，是减少内源污染的直接有效措施。在工程施工时,要密闭机械工作面,对淤泥要安全处置,防止二次污染。但是，清淤后水质只能暂时性地得到改善，随着污染的输入，河流很快又淤积回去，而且工程量大，投资费用高。

河流清淤的成功范例还鲜有报道,目前日本等发达国家,对是否清淤及清淤厚度正进行细致而周密的论证。

3、曝气复氧

污染严重的河流水体由于耗氧量大于水体的自然复氧量，溶解氧很低，甚至处于缺氧(或厌氧)状态。向处于缺氧(或厌氧)状态的河道进行人工充氧（此过程称为河道曝气复氧），可以增强河流的自净能力、改善水质，改善或恢复河流的生态环境。因此，向处于缺氧(或厌氧)状态的河流中进行曝气复氧可以补充河流中过量消耗的溶解氧、增强水体的自净能力，有助于加快黑臭、感官性差等状态的河流恢复到正常的水生态系统。

由于河流曝气复氧工程的良好效果和相对较低的投资与运行成本费用，成为一些发达国家如美国、德国、英国、葡萄牙、澳大利亚及中等发达国家与地区如韩国、中国香港在中小型污染水体乃至港湾和河流水体污染治理中经常采用的方法。

4、换水冲稀

通过工程手段引水稀释受污染水体,短时间内降低水体的污染负荷,改善水生动物、水生植物的生存环境,提高河流的自净能力。但是换水冲稀后污染的总量没有减少，实际是污染物转嫁，如果外来污染持续存在，很快会恢复到原来的污染水平，且浪费了优质的水资源。

通过引水稀释,可使得河流中优势菌种由绿藻转化为大型水生植物,大大改善了河水的水质。但引水稀释导致交换水体的生态体系发生变化,也会产生一定的负面影响。

　二、化学法

1、投加混凝剂

在河流中直接投加“混凝剂”见效快，但是药剂量难以掌握，污染物沉积在河底破坏水底生物环境，且存在污染二次释放的可能性。

2、施用除藻剂

可去除藻类和水中的氮，但是无法除去水体中的磷；化学杀藻剂的生物毒性对鱼类等其它生物的生长危害很大。

化学方法就是针对河流的污染特征投加相应的化学药剂,强制去除污染物质。美国某河流通过投加铝盐,使河中磷由原来的65μg/L下降到30μg/L, 河流水质明显改善。该方法操作简单,但费用较高,易造成二次污染。

三、生物－生态修复技术

当前,国内外的自然水体生态修复技术包括水生植物技术、生物增效技术、微生物制剂技术、人工浮岛技术等。其中，前两种主要是水生植被恢复技术和生物增效技术技术一般作为河流治理的主要技术，应用较为成熟，人工浮岛技术一般作为辅助技术使用。

　　生态修复措施具有原位净化水质,同时也可以恢复水体中的水生生态结构、运行成本低、增加水体自净能力的特点。在自然未受污染水体中,生态系统十分复杂。在水体底质中、颗粒物的表面、驳岸表面上有大量的细菌,这些细菌是水体中有机物质的主要分解者。在水体中的原生动物又以菌类为食。原生动物的捕食能够加速生物膜的更新。衰老的细菌被捕食后,为新的细菌的生长提供了生长空间,使细菌的整体处于较活跃的状态。同时原生动物又是后生动物的食物而底栖生物,如螺蛳,和部分鱼类又以轮虫等后生动物为食。水体中生长的植物在为水体提供氧气的同时也为细菌和微小动物的生长提供了附着空间水体底质和植物组成的复杂环境又为各种生物提供了不同的栖息地。整体的生态系统本身有着一定方向的物质流和能量流,在系统内部,生物之间相互促进或约束,保持着整体的功能和活力。

自然界水体的自净功能主要是依靠水体中的生态系统来完成的,这种自净能力非常巨大,在没有人类干涉的情况下可以分解天然水体中的所有的有机物质,可以自动调节水体中的养分平衡。在一定程度范围内,水体中的有机物质和无机盐类的增加可以提高水体中生物的密度,同时系统内部的物质流和能量流也会相应增加,净化水体中的污染物的能力也会提高。但是一旦超过系统的承载能力,水体生态系统的某些环节就会遭到破坏或丧失功能,而生态系统功能的丧失又会反作用于水体的自净能力。水体的自净能力的减弱又加速了生态系统的崩溃。在恶性的循环之中,水体逐渐丧失了自净的能力。

恢复水体本身的生态结构可以恢复水体的自净能力,通过水体的自净功能达到水体的自我净化,并达到水体和水体内生态系统良性协调发展。在已经发生水质恶化的水体中,完全依靠水体自发的修复作用和简单的物理修复方式很难迅速恢复水体中的生态结构。而在人工参与的条件下,系统而全面的恢复水体的生态结构可以达到水体生态系统良性协调发展的目的。

1、水生植物技术

水生植物是河流生态系统的重要组成部分，具有显著的环境生态功能，利用水生生物法种植水生植物，通过植物的生长转移水体系统中的污染负荷，其发达的根系为微生物提供生长繁殖场所，以分解水中污染物以供植物吸收，具有一定的吸收净化、澄清水质、抑制藻类的功能。

人为创造一定的条件，利用适合相应河流水环境的水生植物及其共生的微环境,构建适合水体特征的水生植物群落,能有效降低悬浮物浓度，提高水体透明度及溶解氧，为其他生物提供良好的生存环境,改善水生生态系统的生物多样性。

2、生物增效技术

生物增效技术将微生物通过一定的技术手段(如利用载体材料、包埋物质或合理控制水力条件等)，使微生物固着生长，提高生物反应器内的微生物数量，从而利于反应后的固液分离，利于除氮和去除高浓度有机物，以及难以生物降解的物质，提高系统的处理能力和适应性生物增效技术立足于恢复、强化微生物群落来净化水体。微生物群落是水生态系统的基础生物组分，既是水体的“清道夫”，降解污染物，给其他的水生生物营造健康的水环境，也是生物链的重要环节，维系正常的物质循环。

微生物（菌类、藻类、原后生动物等）是水体自然净化的主力军，河流受到污染水质变坏，也是因污染量过大超出微生物的消化能力。水质的下降导致部分生物种（包括微生物）丧失了生存环境而逐步消亡，而水生生物结构的改变反过来也助长了水环境恶化的趋势，如此恶性循环导致水生态系统的退化。生物增效技术正是通过营造微生物的生长空间，数百、数万倍放大微生物量，使水体自然的净化能力得到大大加强，放大对污染的消化能力，切断恶性循环。不仅可体现到水质的明显改善，也是促进水生态系统的良性发展循环。

生物增效技术以培育、发展土著微生物为首要目标，这些微生物因适合于原本的水环境而具备高度的活力和持续发展的能力，既不存在因投加微生物菌可能产生的生物入侵，或因微生物死亡需反复投加，也不存在化学药剂的生物危害；因依靠微生物自发的营养消耗净化水体，而不需机械清理而产生的巨大能耗或复杂运营管理要求。

生物增效技术依靠微生物的能力自然净化水体，并紧密结合水生态系统的改善及相互促进发展，因而是一项长期、生态的河流治理措施。

目前，国内外应用比较成熟的生物增效技术为生物巢增效技术，该技术以生物巢为核心，同步净化水质与建立水体生态系统的生态性水体治理维护系统。生物巢是一种新型、高效的生态载体，它融合了材料学、微生物学及水体生态学等学科，采用食品级原材料，通过专利编织技术，将其制成高比表面积、高负荷的，是目前国内外比较先进、比较有效的以生态修复的方法从根本上解决水体净化问题的环保产品。

3、微生物制剂技术

选育高效菌株制成为微生物复合制剂处理污染水体。其过程以酶促反应为基础，通过生物体内产生的具有催化功能的特殊蛋白质作为催化剂,净化污水、分解淤泥、消除恶臭。

微生物制剂技术主要优点是能迅速提高污染介质中的微生物浓度，并可望在短期内提高污染物的生物降解速率，另外生物反应通常条件温和，投资省、费用少、消耗低，而且效果好、过程稳定、操作简便。其缺点是要保持良好的水体改善效果,需根据水体变化情况,不断投加,可作为水体生态修复过程中的辅助措施。微生物制剂技术适合封闭缓流水体，在藻类大量爆发前使用，可弥补微生物制剂通常见效时间较长的缺点。

4、人工浮岛技术

　　生态浮床技术治理水环境与生态修复的原理是通过植物在生长过程中对水体中氮、磷等植物必需元素的吸收利用，及其植物根系和浮床基质等对水体中悬浮物的吸附作用，富集水体中的有害物质，与此同时，植物根系释出大量能降解有机物的分泌物，从而加速有机污染物的分解，随着部分水质指标的改善，尤其是溶解氧的大幅度增加，为好氧微生物的大量繁殖创造了条件，再通过微生物对有机污染物、营养物质的进一步分解，使水质得到进一步改善，最终通过收获植物体的形式，将氮、磷等营养物质以及吸附积累在植物体内和根系表面的污染物搬离水体，使水体中的污染物大幅度减少，水质得到改善，从而为高等水生生物的生存、繁衍创造生态环境条件，为最终修复水生态系统提供可能。

　　人工浮岛中的植物种植方式有漂浮生长、聚苯乙烯泡沫板固定生长、编制袋填充人工基质种植、以毛竹作为漂浮物种植等几种种植方式。直接漂浮种植的植物植株不能挺立；聚苯乙烯泡沫板固定生长的植株可以有较好的分散度,但是泡沫板容易破碎,在改进泡沫板机械性能以后才可以直接用于工程实施之中,也能够在一定程度减少造成景观污染的可能；编制袋填充人工基质种植可以较好的固定植物,植物在基质中可以直立生长,根系可以在很大程度上在基质内充分分布,也可以在水体内有一定的分布,但是基质的存在限制了植物根系与水体的有效接触面积;其他的固定方式也具有使植株根系能够在水体中伸展的特点,可以为水体中微生物的生长提供载体。

人工浮岛中的基质填料也可以为微生物的生长提供载体,增加了有效载体面积。基质填料增加了单位体积内填充物的密度,能够减少水体在植株根系的空间网状结构中交换和流通。人工浮岛,采取植物漂浮生长的方式,可以使该技术适用于不同深度的水体,水位的变化不会对人工浮岛产生影响。

比较好的方案：

目前，生物－生态技术是目前国内外河流治理的主要技术，应用较为广泛和成熟。

建立河道的水生态系统是长期维持水质的根本，本方案主要采用生物巢增效技术对河流进行治理及生态修复，辅以生态浮床和曝气技术（提高水体的溶解氧浓度）。

另外，在治理初期为迅速改善水底的黑臭状况，采用投加环境微生物强化处理。经过一段时间的治理后，水体水质和透明度都得到改善，投加底栖生物（螺类、贝类）和耐污能力较强的鱼类，并搭配种植水生植物，强化水体的自净能力和生态链的完整性。

At present, the treatment and maintenance methods of river eutrophication at home and abroad can be roughly classified into physical method, chemical method, bio-ecological method and so on.

Physical method

1, the sewage

Pollution interception is an effective way to harness rivers. At present, all polluted rivers in China are caused by foreign pollutants far beyond the purification capacity of lakes, which leads to the deterioration of water quality and ecological destruction. Pollution control is widely recognized as an effective measure.

But the river sewage engineering, wide range, including a large number of pipe laying, sewage plant construction, personnel movements, surrounding the river ecological restoration, factories and enterprises pollution control, etc., the large engineering investment, long construction period and complicated project, make the department in charge of many rivers in a certain period of time cannot afford, but progress is slow, and the current sewage work more reflect one river management measures for the relevant department in charge of our strengths, often combined with other management methods.

2, desilting

Due to perennial natural deposition, a large amount of silt has accumulated in the bottom of the river, which is rich in considerable nutrient salts. The removal of sediment from river body can reduce nutrient salts accumulated in surface sediment and potential internal pollution sources, which is a direct and effective measure to reduce endogenous pollution. In the construction of the project, to close the mechanical working face, the silt to safe disposal, to prevent secondary pollution. However, the water quality can only be temporarily improved after dredging. With the input of pollution, the river quickly silted up again, and the project was large and the investment cost was high.

The successful example of river desilting is rarely reported. At present, developed countries such as Japan are carrying out detailed and thorough demonstration on whether the desilting is done and the thickness of the desilting.

3, aeration reoxygenation

River water with serious pollution is in anoxic (or anaerobic) state because the oxygen consumption is higher than the natural reoxygenation. Artificial oxygenation (a process called river aeration reoxygenation) to a river in anoxic (or anaerobic) state can enhance the river's self-purification ability, improve water quality, and improve or restore the river's ecological environment. Therefore, aeration reoxygenation in a river in anoxic (or anaerobic) state can supplement the excess dissolved oxygen in the river, enhance the self-purification ability of the water body, and help to speed up the restoration of the river to the normal water ecosystem in the state of black and smelly, poor sense sense, etc.

Because of river aeration reoxygenation engineering good effects and relatively low investment and operation cost, as some developed countries such as America, Germany, England, Portugal, Australia and moderately developed countries and regions such as South Korea, Hong Kong, China, in small and medium pollution water and harbor and river water pollution control in the frequently used methods.

4. Change water to flush dilute

By means of engineering, water is diverted to dilute the polluted water body, so as to reduce the pollution load of water body in a short time, improve the living environment of aquatic animals and aquatic plants, and improve the self-purification ability of rivers. However, the total amount of pollution did not decrease after the water was changed and diluted. In fact, it was the transfer of pollutants. If the external pollution persisted, it would soon return to the original pollution level and waste high-quality water resources.

Through water dilution, the dominant bacteria in the river can be transformed from green algae to large aquatic plants, which greatly improves the water quality of the river. However, dilution of diversion water will lead to changes in the ecological system of exchange water body, which will also have a certain negative impact.

2. Chemical method

1. Add coagulant

The direct addition of "coagulant" in the river has a quick effect, but the drug dose is difficult to grasp, the pollutant deposition on the river bottom damages the bottom biological environment, and there is the possibility of secondary release of pollution.

2. Apply algae remover

Remove algae and nitrogen from water, but not phosphorus; The biological toxicity of chemical algicide is harmful to the growth of fish and other organisms.

The chemical method is to add the corresponding chemical agents according to the pollution characteristics of the river and remove the pollution substances forcibly. By adding aluminum salt to a river in the United States, the phosphorus in the river dropped from 65 mug /L to 30 mug /L. This method is simple to operate, but high cost, easy to cause secondary pollution.

Bio-ecological restoration technology

At present, the natural water body ecological restoration technology at home and abroad includes aquatic plant technology, biological enhancement technology, microbial preparation technology, artificial floating island technology and so on. Among them, the first two are mainly aquatic vegetation restoration technology and biological efficiency enhancement technology, which are generally used as the main technology of river management and are relatively mature in application. Artificial floating island technology is generally used as auxiliary technology.

Ecological restoration measures have the characteristics of in-situ purification of water quality, restoration of aquatic ecological structure in water bodies, low operating cost and increase of self-purification ability of water bodies. In natural unpolluted water, ecosystems are complex. There are a lot of bacteria in the bottom of water, on the surface of particulate matter and on the surface of revetment. Protozoa in water also feed on fungi. Protozoan predation can accelerate the renewal of biofilm. After the aging bacteria are preyed on, the growth space is provided for the growth of new bacteria, making the whole bacteria in a more active state. At the same time, protozoa are the food for metazoan animals, while benthic creatures such as spiral lions and some fish feed on metazoan animals such as rotifers. The plants growing in water not only provide oxygen for the water, but also provide adhesion space for the growth of bacteria and micro-animals. The complex environment composed of water bottom and plants also provides different habitats for various organisms. The whole ecosystem itself has a certain direction of material flow and energy flow, in the system, between organisms promote or restrict each other, maintain the overall function and vitality.

The self-purification function of natural water body mainly depends on the ecosystem in the water body. This self-purification ability is very great. Without human intervention, all organic substances in the natural water body can be decomposed, and the nutrient balance in the water body can be automatically adjusted. To a certain extent, the increase of organic substances and inorganic salts in the water can improve the density of organisms in the water, meanwhile, the material flow and energy flow in the system will also increase correspondingly, and the ability of purifying pollutants in the water will also be improved. However, once the carrying capacity of the system is exceeded, some links of the water ecosystem will be destroyed or lose its function, and the loss of the function of the ecosystem will react on the self-purification ability of the water body. The weakening of the self-purification ability of water also accelerates the collapse of the ecosystem. In a vicious cycle, water gradually loses its ability to purify itself.

The restoration of the ecological structure of the water body can restore the self-purification ability of the water body, achieve self-purification of the water body through the self-purification function of the water body, and achieve the sound and coordinated development of the water body and the aquatic ecosystem. In water bodies where water quality has deteriorated, it is difficult to quickly restore the ecological structure of water bodies by relying entirely on spontaneous restoration and simple physical restoration. Under the condition of artificial participation, a systematic and comprehensive restoration of the ecological structure of the water body can achieve the benign and coordinated development of the water body ecosystem.

1. Aquatic plant technology

Aquatic plants is an important part of the river ecosystem, and has significant environmental ecological function, using the method of aquatic organisms grow aquatic plants, plant growth through transfer of water pollution loads in the system and its developed root system for microbial growth breeding sites, to break down the water for plants absorb pollutants, has certain absorption purification, clarify the function of the water quality, inhibit the algae.

Artificially create certain conditions, the use of suitable for river water environment of aquatic plants and its corresponding symbiotic environment, to construct water characteristics of aquatic plant community, can effectively reduce the concentration of suspended solids, improve the water transparency and dissolved oxygen, to provide a good living environment to other creatures, to improve the biodiversity of the aquatic ecosystem.

2. Biosynergy technology

Biological technology will increase microbial through certain technical means (such as the use of carrier materials, embedding material or reasonable control hydraulic conditions, etc.), make the growth of microbial fixation, improve the microbial number inside the bioreactor, thus conducive to the solid-liquid separation after reaction, nitrogen removal and remove high concentrations of organic matter, and is hard to biodegradable materials, improve system capacity and adaptability of biological synergistic technology based on the recovery, strengthen the microbial communities to purify the water. Microbial community is the basic biological component of water ecosystem, which is not only the "scavenger" of water body, degrading pollutants, creating a healthy water environment for other aquatic organisms, but also an important link of biological chain, maintaining normal material circulation.

Microorganisms (fungi, algae, protozoan animals, etc.) are the main force in the natural purification of water bodies. The polluted water quality of rivers is deteriorated, which is also due to the pollution that exceeds the digestibility of microorganisms. The decline of water quality leads to the gradual extinction of some biological species (including microorganisms) without living environment, and the change of aquatic biological structure in turn also contributes to the trend of water environment deterioration, such a vicious circle leads to the degradation of water ecosystem. By creating the space for the growth of microorganisms, the biosynergy technology amplifies the microbial biomass by hundreds or tens of thousands of times, greatly enhancing the natural purification capacity of water bodies, amplifying the digestion capacity of pollution, and cutting off the vicious circle. It can not only reflect the obvious improvement of water quality, but also promote the benign development cycle of water ecosystem.

Indigenous microbial biological synergistic technology in training and development as the priority, these microbes due to water environment suitable for the originally with the height of the vitality and the ability of sustainable development, there is neither may be produced by adding the microbial biological invasion, or because of microbial death to repeated dosing, and no chemical biological hazards; Water purification is based on the spontaneous nutrient consumption of microorganisms without the huge energy consumption or complex operation management requirements caused by mechanical cleaning.

Biosynergy technology relies on the ability of microorganisms to purify water body naturally, and closely combines the improvement of water ecosystem and mutual promotion of development. Therefore, it is a long-term and ecological river management measure.

At present, the most mature biological efficiency enhancement technology at home and abroad is biological nest efficiency enhancement technology, which takes biological nest as the core, synchronously purifies water quality and establishes ecological water body management and maintenance system of water body ecosystem. Biological nest is a new and highly efficient ecological carrier, it is a blend of subjects such as material science, microbiology and water ecology, USES the food grade raw material, through the patent weaving technology, the high specific surface area, high load, is the most advanced at home and abroad, the most effective method for ecological restoration of fundamentally solve the problem of water body purification environmental protection product.

3. Microbial preparation technology

The strains with high efficiency were selected and made into microbial compound preparation to treat polluted water. The process is based on the enzymatic reaction and USES the special protein with catalytic function produced by the organism as the catalyst to purify sewage, decompose silt and eliminate odor.

The main advantage of microbial preparation technology is that it can rapidly increase the concentration of microorganisms in the contaminated media and is expected to improve the biodegradation rate of pollutants in a short time. Its disadvantage is that in order to maintain a good water improvement effect, continuous addition is needed according to the change of water body, which can be used as an auxiliary measure in the process of water body ecological restoration. Microbiological preparation technology is suitable for closing slow-flow water body and can be used before algae bloom, which can make up for the disadvantage that microbiological preparation usually takes longer to take effect.

4. Artificial floating island technology

Ecological floating bed technology is the principle of management of water environment and ecological restoration through the plant in the process of growth of water absorption of nitrogen, phosphorus and other plant essential elements in use, and its roots and floating bed matrix on the adsorption of suspended solids in water, the concentration of harmful substances in water body, at the same time, plant roots can release a large number of secretion of the degradation of organic matter, so as to accelerate the decomposition of organic pollutants, as the improvement of some water quality indicators, especially the increase of dissolved oxygen, create conditions for aerobic microbial multiply, again through the microbes to further decomposition of organic pollutants and nutrients, improve water quality further, Ultimately through the harvest plant form, accumulation of nitrogen, phosphorus and other nutrients and adsorbed on the surface of the plants and root, pollutants move out water, make the pollutants in water are greatly reduced, the water quality improved, so that higher survival and reproduction of aquatic creatures in the ecological environment conditions, provide may eventually repair water ecosystem.

The planting methods of artificial floating island include floating growth, fixed growth of polystyrene foam board, artificial matrix filled with woven bag, and bamboo as floating object. Plants planted directly floating cannot stand upright; Plants with fixed growth of polystyrene foam board can have good dispersion, but the foam board is easy to break. After improving the mechanical properties of the foam board, it can be directly used in the implementation of projects, and can also reduce the possibility of causing landscape pollution to a certain extent. Artificial matrix filled with woven bag can be used for planting plants. Plants can grow upright in the matrix, and roots can be fully distributed in the matrix to a large extent, or in water bodies to a certain extent. However, the existence of matrix limits the effective contact area between plant roots and water bodies. Other fixation methods also have the characteristics of allowing the plant root system to stretch in the water, which can provide support for the growth of microorganisms in the water.

The matrix filler in the artificial floating island can also provide the carrier for the growth of microorganisms and increase the effective carrier area. Matrix fillers increase the density of fillers per unit volume and reduce the exchange and circulation of water in the spatial network of plant roots. Artificial floating islands adopt the way of plant floating and growing, which can make the technology applicable to water bodies of different depths. The change of water level will not affect the artificial floating islands.

Best solution:

At present, bio-ecological technology is the main technology of river management at home and abroad.

The establishment of river water ecosystem is the foundation of long-term maintenance of water quality. This plan mainly adopts biological nest enhancement technology for river management and ecological restoration, supplemented by ecological floating bed and aeration technology (improve dissolved oxygen concentration of water body).

In addition, in the early stage of treatment, environmental microorganisms were added to improve the black and smelly condition of the water bottom. After a period of treatment, water quality and transparency are improved. Benthic organisms (snails and shellfish) and fish with strong pollution resistance are added, and aquatic plants are planted to enhance the self-purification ability of water body and the integrity of the ecological chain.