Experimental Study of Al-Modified Zeolite with Oxygen Nanobubbles in Repairing Black and Odorous Sediments in River Channels

Abstract

As an extreme phenomenon of water pollution, black and odorous water not only causes ecological damage, but also severely restricts urban development. At present, the in-situ remediation technology of black and odorous sediment from river channels is still undeveloped, and there are many bottlenecks in the key technologies of black and odorous sediment pollution control and ecological restoration. In this study, three experimental tanks are used to explore the effects of Al-modified zeolite with oxygen nanobubbles on repairing black and odorous sediment from Shichuan river. Which one of the tanks plants Typha orientalis and Canna indica L. (TC), the other plants the same plants and adds Al-modified zeolite with oxygen nanobubbles (TC+AMZON), and the last used as comparison test is not processed (CS). The results show that Nitrogen(N) and phosphorus(P) in the sediment are released violently to the surrounding water. However, TC+AMZON can effectively inhibit the release of P. The amount of soluble reactive phosphorus (SRP) of pore water in the sediment released reaches the maximum at 40 d, and it is 122.97% and 74.32% bigger in TC and CS than that in TC+AMZON. The amount of total phosphorus (TP) of pore water in the sediment released reaches the maximum at 70 d, and it is 260.14% and 218.23% bigger in TC and CS than that in TC+AMZON, respectively. (2) TC+AMZON can significantly increase the dissolved oxygen (DO) and oxidation-reduction potential(ORP) of pore water in the sediment in the early stage of the test. On the 0 d, the DO content in TC+AMZON reaches 10.6 mg/L, and it is 112.0% and 178.95% bigger than that in TC and CS, respectively. The change laws of ORP in the sediment is consistent with that of DO. (3) TC+AMZON can significantly improve the transparency and reduce the content of chlorophylla of the upper water, and can slightly reduce the N and P content of the upper water. The transparency of the upper water in TC+AMZON is increased by 130.76% and 58.73% compared with TC and CS, and the content of chlorophylla is decreased by 55.6% and 50.0% compared with TC and CS.