Assessment of Phytotoxicity in the Compost Derived Through Different Techniques from Municipal Solid Waste and Industrial Solids

Co-composting of municipal solid waste with that of industrial solids is gaining importance nowadays due to the possibility of the disposal of both the waste simultaneously in an eco-friendly manner as soil-enhancer for nutrient hungry soils. This study focuses on the suitability of co-composting organic part of municipal solid waste (OPMSW) generated from Coimbatore city with industrial solids from pulp and paper (P), sugar (S) and dairy (D) industries in three different proportions, i.e. 3:1, 6:1 and 9:1 designated as 1, 2 and 3, respectively, and subjecting to three different composting techniques like windrow composting (W), vermicomposting (V) and twin process (Windrow + Vermicomposting, WV). The phytotoxicity of the finished compost in each case, i.e. from nine different combinations for each industrial solid, has been analysed in terms of germination index (GI) and vigour index (VI using Lycopersicum esculentum (Tomato plant—test species recommended by USEPA/FD). In the group P–P3, WV showed highest GI (62) and VI (764); in group S–S3, WV showed highest GI (55) and VI (703); and in group D–D2, WV showed highest GI (57) and VI (743) than their corresponding counterparts. This shows that the twin process (WV) to be an ideal method for treatment of OPMSW with the sludge from various industries due to its short duration of processing (40 days) and better quality of the final compost than their counterparts with respect to phytotoxicity.