我国的工业化处于高速发展阶段。在此阶段，环境治理，特别是水环境治理尤为重要。河道中的水质状况会直接影响到人们的生存环境和生活质量。由于我国城市水环境污染严重，城市河道中的水体多被有机污染物和氮、磷等污染物污染，黑臭水体已是我国各城市河道普遍存在的现象。城市黑臭河道的治理将是今后重点解决的环境问题。

一、城市河道黑臭的形成

“黑臭”被认为是一种水体中有机污染物厌气分解的生物化学现象，是水体有机物污染的极端现象。由于水体中有机污染物、氮磷富含量过多，造成水体缺氧，有机物腐败。长时间接触，对城市居民的健康及城市生态安全构成了极为严重的威胁。大量的有机物进入水体后，破坏了水体自身所可以降解及净化的系统，在经过分解、腐败的过程后产生腐殖质等发臭物质沉积在河道底部，挥发性，刺激性气体，如硫化氢、甲烷等逸出水面。排放进入水体的重金属铁、锰等污染物与水中的硫形成了硫化物，形成大量带电胶体的黑色悬浮颗粒。导致河流黑臭的因素：有机物，底泥，水温，DO等。

二、城市河道黑臭治理技术

1、人工曝气

水体富营养化、腐殖质的大量增多造成水体供氧和耗氧不平衡是造成水体黑臭的主要原因之一。人工曝气复氧是治理河道黑臭的有效措施。我国在2000年开始应用曝气复氧技术。人工曝气复氧技术主要是通过向黑臭河道进行增氧，以此来增加水体中DO的含量，强化水体自净的功能，促进水体生态系统的恢复。根据实际治理环境因素的不同，人工曝气复氧一般可以分为三类：鼓风扩散曝气、水面转刷曝气、船载移动曝气。

2、底泥疏浚

底泥是河道中污染物的源头，底泥疏浚可以永久性地将河道、湖泊底泥去除，所以底泥疏浚是被广泛应用的治理河道黑臭的技术方法。底泥疏浚主要方法有：干床清挖、抓斗挖泥船和水力冲挖等方式。通过以上方法来增加港口河道等航道的疏通，增加通航水深；达到贮水，排涝泄洪，调整水系，改善水流条件；去除湖泊河道和河流表层沉积物中的污染物，改善水体，提高水体泄洪和自净功能。

3、强化絮凝

强化絮凝是城市河道黑臭治理的一种化学方法，通过使用化学药剂，铁盐、铝盐同氧化剂，如双氧水及沉淀剂石灰石等作用，去除黑臭河道中悬浮物质以及溶解性氮、磷，降低水的色度，主要用于感官视觉上的改善，多用于黑臭河道治理的部分环节。通过化学絮凝的作用，短时间内大幅度改善水质，并不过多用于实际工程应用中。

4、生物治理与生态修复

生物生态方法可以从根本上，长久有效地改善河道水体水质，是国内外近几年发展十分迅速的一种方法。自然水体的自净以及修复主要是通过水体中微生物的作用，对水中污染物，富营养化的氮、磷进行吸收以及转化。重新构筑水体微生物系统，是解决城市河道黑臭的有效途径。生物生态方法主要包括微生物强化技术、生物膜技术、植物精华技术以及生物生态净化技术。

三、沉水式鼓风机的应用案例

四、沉水风机的优势

沉水式鼓风机是罗茨鼓风机的升级版，在污水处理和河道治理中占有一定的优势：

①较低的能源损耗：

沉水式鼓风机由于沉入水中，减少轴承座的散热孔，相对的也减低压力耗损，提高整机效率。

运转中之鼓风机，因放在水中，故声音在空气与水之界面被折射入水中，而不传入空气中，同时水与槽壁亦同样折射回去而达到灭音之效果。

③不须制作机房：

沉水式罗茨鼓风机因置于水中，固不需要另制作机房，同时鼓风机置放于水槽中，不占用空间，所以能有效利用空间。

④寿命延长及超长保养周期：

由于风机沉于水中，故散热效果佳，降低内部易损件的损耗，得以延长使用寿命，保养周期为2年。

城市河道黑臭治理，是一个亟待解决的问题。城市河道是水污染的源头，随着城市人口的增多，城市河道黑臭治理已迫在眉睫。

China's industrialization is in the stage of rapid development. In this stage, environmental management, especially water environmental management is particularly important. Water quality in the river will directly affect people's living environment and quality of life. Due to the serious pollution of urban water environment in China, the water bodies in urban river courses are mostly polluted by organic pollutants, nitrogen, phosphorus and other pollutants. The management of urban black and smelly river will be the key environmental problem to be solved in the future.

I. the formation of black and smelly urban river courses

"Black odor" is considered as a biochemical phenomenon of anaerobic decomposition of organic pollutants in water and an extreme phenomenon of organic pollution in water. Due to the excessive content of organic pollutants, nitrogen and phosphorus in the water, water anoxia, organic corruption. Long-term exposure poses a serious threat to the health of urban residents and urban ecological security. After a large amount of organic matter enters the water body, it destroys the degradation and purification system of the water body itself. After the process of decomposition and corruption, smelly substances such as humus are deposited at the bottom of the river. Volatile and irritating gases, such as hydrogen sulfide and methane, escape from the water surface. The heavy metal iron, manganese and other pollutants discharged into the water form sulfide with sulfur in the water, forming a large number of charged colloidal black suspended particles. Causes of black and smelly river: organic matter, sediment, water temperature, DO, etc.

Two, urban river black and smelly control technology

1. Artificial aeration

One of the main causes of black and smelly water is the imbalance of oxygen supply and consumption caused by eutrophication and a large amount of humus. Artificial aeration reoxygenation is an effective measure to control black and smelly river. In 2000, aerated reoxygenation technology was applied in China. Artificial aeration reoxygenation technology is mainly used to increase the content of DO in water body, strengthen the function of water body self-purification and promote the restoration of water body ecosystem by adding oxygen to the black and smelly river. According to the actual treatment of environmental factors, artificial aeration reoxygenation can be generally divided into three categories: air diffusion aeration, water surface to brush aeration, ship borne mobile aeration.

2. Dredge the bottom mud

Sediment dredging is the source of pollutants in river courses. Sediment dredging can permanently remove sediment from river courses and lakes. Therefore, sediment dredging is a widely used technical method to control black and smelly river courses. The main dredging methods include dry bed cleaning, grab dredger and hydraulic flushing. Through the above methods to increase the dredging of port channels and other channels, increase the navigable depth; To reach water storage, drainage flood discharge, adjust the water system, improve the flow conditions; Remove pollutants from the surface sediments of lakes and rivers, improve water bodies, and improve flood discharge and self-purification functions of water bodies.

3. Strengthen flocculation

Enhanced flocculation is a chemical method of urban river black smelly governance, through the use of chemicals, iron and aluminium salt with oxidant, such as hydrogen peroxide and precipitant limestone, remove suspended material in the black smelly river and soluble nitrogen, phosphorus, decrease chroma of the water, mainly used for the improvement of the visual senses, multi-purpose at black smelly river management part of the link. Through the action of chemical flocculation, water quality can be improved greatly in a short time.

4. Biological governance and ecological restoration

Biological ecological method can improve river water quality fundamentally and effectively for a long time. The self-purification and restoration of natural water bodies are mainly the absorption and transformation of water pollutants, eutrophicated nitrogen and phosphorus through the action of microorganisms in water bodies. Reconstructing water microbial system is an effective way to solve the problem of black and smelly urban watercourses. Biological ecological methods mainly include microbial enhancement technology, biofilm technology, plant essence technology and biological ecological purification technology.

Application case of submerged blower

Four, the advantages of submerged water fan

Submersible blower is an upgraded version of roots blower, which has certain advantages in sewage treatment and river treatment:

(1) lower energy consumption:

The submerged blower can reduce the heat dissipation hole of the bearing seat, reduce the pressure loss and improve the efficiency of the whole machine.

When the blower is in operation, the sound is refracted into the water at the interface between air and water, but not into the air.

(3) do not need to make room:

Submerged roots blower in water, solid do not need another production room, at the same time the blower placed in the tank, do not take up space, so can effectively use the space.

(4) life extension and ultra-long maintenance cycle:

Because the fan is immersed in water, it has a good heat dissipation effect, reduces the loss of internal wearing parts, and thus prolongs the service life and the maintenance cycle is 2 years.

It is an urgent problem to control the black and foul smell in urban watercourses. Urban river courses are the source of water pollution. With the increase of urban population, it is urgent to control the black and smelly urban river courses.