Recent decades have witnessed the rapid development of industrialized marine culture in the world. At the same time, the pollutant discharge produced by marine culture has caused serious environmental problems at coastal regions.

To deal with the issue, a research group headed by Prof. Li Dapeng from the Qingdao-based CAS Institute of Oceanology has developed a cleaning device for cultivating wastewater by employing macroscopic algae as filling material. The feat has recently been granted a patent right for invention from the State Intellectual Property Office.

According to their design, the cultivating device comprises transparent glass boxes stacking with each other with volume shortened layer by layer from bottom to up. The back of a glass box employs sunlight as light source. The top of each box is equipped with an inlet pipe, and bottom with an outlet pipe, serving as the inlet pipe for the next box. The water outlet pipe of the bottom glass box is connected with main water outlet pipe, and the top glass box is connected with main water inlet pipe, while refrigerating pump and water pump are equipped in the pipeline between the main water outlet pipe and main water inlet pipe.

The invention is noted for a number of strong points. First, the glass boxes could be filled with large-size marine algae such as the sea asparagus, sea lettuce and pololithon cultured in high-density photo-biological reactors. Then, the seawater flow passes through cooling pumps so that its temperature might be regulated at will. Furthermore, at the pipework's outlet, the water quality can be sampled for a hydrologic analysis while substandard water might be re-pumped by the driving pumps into the top box in a circuit of recycled purification. The invention also features air pumps capable of pouring air directly into the seawater.

When the cultivating wastewater flows into the upper glass box from the main water inlet pipe and contacts with algae completely, the metabolism and photosynthetic oxygenation of the algae will be carried out thoroughly on the condition of using sunlight as light source and aerated by air pump. It can adsorb a large quantity of production factors such as C, N and P to enrich the nutriment stock, and the wastewater will be cleaned by the algae in the middle and bottom of the glass box, and at the same, the photosynthetic oxygenation will increase the dissolved oxygen in seawater to improve water quality.、

Based on the biological traits of the large-size seaweed, the invention is noted for its continuous, practical and semi-automated operation, equipped with a controllable system over the culturing conditions, featuring a higher efficiency in utilization of the light energy in a continuous or semi-continuous way.