NOVELTY - Surface aerobic biocomposting molasses-based distillery wastewater, i.e. spentwash, comprises preprocessing solid feed mixture comprising pressmud, recycled compost and dried sugarcane residue; creating windrow from the solid feed mixture; adding microbial culture; applying spentwash for first 5 weeks; reducing spentwash application on sixth week; turning and mixing the windrow on seventh and eighth weeks; curing for the last 2 weeks; post-processing compost product comprising nutrients-rich organic compost manure; and recycling the compost product back to input solid feed mixture.    USE - Method for surface aerobic biocomposting molasses-based distillery wastewater to produce nutrient-rich organic compost manure (claimed) for application to agricultural land.    ADVANTAGE - The process is environment-friendly and less energy intensive; has low cost; leads to complete utilization of distillery wastewater and facilitates weight and volume reduction of wastewater, resulting to zero liquid discharge; and produces good quality organic compost manure. The compost manure is stable and free from pathogens and plant seeds.    DETAILED DESCRIPTION - Surface aerobic biocomposting molasses-based distillery wastewater, i.e. spentwash, comprises:    (A) preparing solid feed mixture by mixing pressmud with recycled compost and dried sugarcane residue;    (B) preprocessing solid feed mixture involving proportioning, drying, mixing all ingredients, and conditioning pressmud;    (C) creating windrow of desired size and shape from the solid feed mixture on compost yard;    (D) adding microbial culture to the mixture;    (E) applying spentwash over the windrow initially for first 5 weeks;    (F) reducing spentwash application on sixth week;    (G) turning and mixing the windrow on seventh and eighth weeks;    (H) curing the windrow for the last 2 weeks;    (I) obtaining nutrients (nitrogen, phosphorus and potassium)-rich organic compost manure in high yield as compost product from the liquid spentwash effluent;    (J) post-processing compost product involving aging, segregating and separating coarse dried sugarcane residue; and    (K) recycling the compost product back to input solid feed mixture to vary or improve feed substrate properties like moisture content, bulk weight (density), porosity, free air space, biodegradable volatile solid (BVS) content and solid loading rate.    The spentwash is applied using pipe and valve arrangements through calibrated greater than or equal to 1000 L high-density polyethylene mounted on a tractor trolley and/or directly through piping grid network provided on the compost yard.