Aquatic weeds and their utilization 3097.1 Objectives, benefits, and limitations
7.1.1 Objectives
The main purposes of using aquatic weeds in waste recovery and recycling are
for waste stabilization and nutrient removal, and conversion of the harvested
weeds into productive uses. Aquatic weeds provide a medium for bacteria to be
attached and grow at their roots and stems, to stabilize the waste. The presence
of weeds in the aquatic medium and subsequent harvesting enable the nutrient
removal from the wastewater. Even though stabilization of waste is a slow
process in aquatic systems, the removal efficiency is high and can produce an
effluent superior or comparable to that of any other treatment systems. The
productive uses of aquatic weeds are given below.
7.1.2 Benefits
Aquatic weeds can be used, directly or after processing, as soil additives, mulch,
fertilizer, green manure, pulp and fibre for paper making, animal feed, and
human food, organic malts for biogas production and for composting. If
properly designed, the operation and maintenance of the aquatic weed system
does not require highly skilled manpower.
7.1.3 Limitations
Land requirement
Waste treatment with aquatic weeds requires large area of land at reasonably
low cost. This will become one of the major limitations in urban areas, but in
rural areas this will not be a problem.
Pathogen destruction
The reliability of an aquatic system with regard to pathogen destruction is low
because the inactivation mechanism is natural die-off during long detention
time, and some of the aquatic plants will provide suitable condition for the
survival of pathogenic microorganisms.
End uses
Most of the end use of aquatic weeds are for agricultural and livestock rearing
purposes. So the aquatic weed systems are suitable for rural areas.