Abstract: Laxmital pond in Jhansi city is heavily polluted due to unrestricted
discharge of domestic sewage and supported growth of some aquatic macrophytes.
Macrophytes growing in wastewater ponds assimilate nutrients and thus
harvesting and vermicomposting of macrophytes, recycle nutrients from the
wastewater. Hence, the present investigation explored possibility to recycle
mixture of macrophytes biomass (MMB) from sewage pond. The recycling potential of MMB in cattle dung (CD) as bulking was determined on the basis of five
different amendment ratios: 0% (T_1), 25% (T_2), 50% (T_3),
75% (T_4) and 100 (T_5),
in the laboratory condition employing Eisenia foetida for 120 days. Worm growth
and reproduction was significantly decreased with increasing percentage of MMB
as compared to control. Worm failed to reproduce in MMB without CD (T_5), but
grew steadily and reproduced well up to 25% MMB + CD (T_2). Physicochemical
analysis of vermicompost recorded a clear trend in reduction of pH (5.0-17.1%),
total organic carbon (TOC) (29.2-71.1%) and carbon:nitrogen C:N) ratio
(48.3-88.4%), whereas increase in total Kjeldhal nitrogen TKN) (36.9-148%),
total phosphorus TP) (53.7-120.2%) and ash (26.2-262.6%) than their respective
initial values. Similarly, vermicomposting also caused significant reduction in
total heavy metal (Zn, Cu, Pb and Cd) contents. The percentage of total N, P
and K contents, examined in plant available forms were relatively high in T2
than other treatments. The results suggested that WH from domestic sewage up to
25% MMB (plus CD) is appropriate to recycle and vermicompost produced is useful
for sustainable agriculture.
Keywords: Macrophyte mixture, cow dung, earthworm biomass, heavy metals, available nutrients
