Prevent and control water pollution is an important part of ecological environment protection. Water environment monitoring and pollution source tracing is the basic measure. In the past, it was very difficult to realize this purpose via manual methods to accurately prevent pollution.Pollution source tracing is the pain spot of the industry too. Nowadays, technology had developed and there are many advanced equipment being used to detect water pollution sources. They include underwater optical camera, underwater imaging sonar, side scan sonar, water quality sampling (by analyzing water temperature, pH value, dissolved oxygen, turbidity, COD), etc.Location：River in some Industry ZoneEnvironment：Quite complicated. Water qulity is bad and smell pungent stinky. First of all, the locan Environment Protection Department is urgent to find out the polution source, then they can make out resoving method. So that they are able to realize the sustainable development of ecological environment.Difficulties：
1）Surveying the whole 9km river, 6km of which is along the Industry Zone area. The current is very slow. Most of the river bank is hard and some is soft. River is narrow and two side is shallow full of seaweed. It is not convenient to dirve traditional motor boat. So unmanned surface vehicle is a good choice.
2）In order to locate the hidden pipeline quickly and accurately, it is quite important to select the right equipment to be installed on the USV. They could not be too heavy and should be low power consumption. Furthermore, the water is turbid and visibility is poor. So the optical camera equipment cannot be used. While water quality sampling can only analysis the pollution situation of the water nearby, but can not accurately find the location of hidden pipe. Under this kind of environmental condition, only the side scan sonar is able to meet the requirements of the project.
According to the on-site environment and customer demand, USV integrated with side scan sonar is the best solution to check and locate the hidden pipe, which flow out sewage. The Environmental Protection Department decided to conduct a hidden pipe inspection test via a small unmanned surface vehicle carrying Hydro-Tech ES900 series sonar.1) The USV selected is a small inflatable boat. It has many feature of light weight, easy for transportation, big payload, long durability and stable driving attitude.2) The side scan sonar used comes from Hydro-Tech ES900, which is perfect for second development and integraion into all kinds of small unmanned platforms, including USV, ROV etc. Since is has many good advantages of clear image, manual automatic identification, strong anti-interference ability, easy operation and simple structure and friedly compatibility and so on.
Hydro-Tech ES900 is very easy to install. Below the quick installation through mountin brack.After adjust the transducer angle and connect all the cables, the engineers start to scan and survey the two river banks. Control the USV to drive at the uniform speed along the river with 5-10m distance between the bank. Scan the left bank first, then turn around and scan the right bank. When met any suspected area or special terrain, scan carefully and repeatedly if need. At the same time adjust the sonar angle according to the river current flow direction.Scanning Result & AnalysisAfter the scanning & survey, it is obvious that there are many hidden pipes in water. With the coordinate information of the suspected hidden pipe, the Environmental Protection Department accurately found out these sewage pipes, then arrange special person to double check locally and confirmed that it was these hidden pipes caused the odor emitted by the river. Finally the factories owing these hidden pipes was ordered to rectify and destroy these sewage pipes the industrial zone.From this test, we proved that Hydro-Tech ES900 is not only a sharp tool to detect hidden pipes, but also capable of accurately drawing any small target in water, including shipwrecks, underwater steps, grooves, embankments and culverts, etc. Hydro-Tech ES900 perfectly solves the client's problems. It can produce clear image and has strong anti-interference ability. The more important is its high stability which greatly ensure scanning data accuracy and finish the hidden pipe detection task successfully.The operating engineers on the shore can monitor the working state of the USV through remote communication technology. The underwater side scan sonar realizes the accurate detecting and positioning of the underwater hidden pipe through the real-time scanning sonar image, so that the hidden pipe has nowhere to hide. At the same time, it also makes the troubleshooting work safer and more efficient. 