Effect of Digestate from Rubber Processing Effluent on Soil Properties

Abstract

Abstract. Anaerobic digestion of rubber processing effluent (RPE) was conducted at 1:1 Effluent to
Inoculums ratio to obtain biogas at a 40–day retention time. The physicochemical properties of the
RPE were determined before and after anaerobic digestion. Digestate obtained thereof was used as
soil amendment to investigate its bio-fertility potential. To study the effects, three kilograms (3Kg)
of soil samples were separately treated with 0, 200, 400, 600 of the digested RPE. The effluent applied
were thoroughly mixed with the soil, watered regularly and left for eight weeks for adequate
mineralisation and equilibration. The soil physicochemical properties were determined before and
after the amendment. The results from the amended soils showed that application of the digestate
enhanced soil quality (as soil organic carbon, N, P, K, Ca, Na and % base saturation were significantly
higher than in the control). However, the soil pH remained in the acidic region and the soil
exchangeable acidity reduced.