School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
The topic of the paper is the biotechnological sealing of sand using calcium- or iron-based biogrouts. These processes are modeling the sealing of sand during construction of aquaculture pond in the arid desert. The experiments showed that it is possible to conduct biosealing of sand using microbially induced calcium carbonate precipitation performed by the spraying of dead but urease-active bacteria. The sealing was also effective due to ferric hydroxide precipitation in sand after percolation of ferrous-containing solution produced from iron ore and cellulose by the community of acidogenic and iron-reducing bacteria. These treatments of sand can decrease its hydraulic conductivity from the level of 10−4 m/s to the level of 10−8 m/s, which is an acceptable level for the aquaculture ponds. The cost of this sealing, especially when the local sources of calcium chloride brain or low grade iron (hydr)oxides of iron ore are applied, could be several times lower than any other known methods of the sand sealing, and could be used in aquaculture practice for the construction of fish, prawns, or algae ponds in sand of the arid deserts.