CONSTRUCTION WASTE CAN OFFER AN EFFECTIVE SUBSTITUTE FOR RIVER SAND

     Secondary sand recycled from construction waste can offer an effective substitute for the diminishing river sand resources in the state, a paper presented at a national seminar on" Mining of River Sand and its impact on the environment' held at the center of water Resources Development and management (CWRDM) Kozhikodu.
     Authored by D Padmalal  scientist at the center for Earth Science Studies ( CESS), the paper on " construction Grade Sand- Sources and strategies' suggested that a variety of waste materials such as concrete and stone masonry could be recycled as secondary aggregates for construction. Concrete and ricks may be crushed and graded. In the U.S recycled secondary aggregate contributes about one percent of the total aggregate demand in the country. Recycling of concrete rubble not only avoids the problem associated with the disposal of demolition wastes, it also reduces the environmental impact of new aggregate generation the paper pointed out. the effective conservation measures and optimal utilization of the limited river sand resources were imperative for the state to tide over the crisis caused by the acute scarcity of sand.He suggested the use of river sand only for construction and not for land filling or reclamation.  The paper proposed the evolution of new building technologies with reduced sand requirement and alternatives to concrete and cement-sand mixture.It also recommended stiff penalty for over exploitation of river sand.
      He advocated separation of sand aggregate management from river management and appropriate legislation for aggregate management in the state. There is an urgent need to stregthen multi-disciolinary studies on river sand auditing in all rivers in Kerala to estimate the quantity of sand that could be mined from river channels. Steps to enforce the Kerala River Bank protection and Regulation of Removal of sand Act 2001 was another major proposal.
    The paper also underlined the importance of creating public awarness of river sand mining, the state of environment of rivers, the fiite charactor of river sand and the immediate need for control measures. Dredging for marine sand is practised in many countries like the Netherlands, Great Britian, Denmark, Germany,Belgium, Japan,Persian Gulf and France" He however,pointed out that offshore mining should be based on a resource survey, techno-economic feasibility and  to environmental impact assessment. A new approach that ensured regulated use of river sand, cost effective alternatives and steps to conserve river sand were required to reduce the gap between demand and supply inthe construction industry on the one hand and environmental protection on the other.

Prof.John Kurakar