Effects of aeration cycles and hydraulic retention time on the sequencing batch treatment of flushed swine manure

摘要

A pilot plant with the capacity to treat up to 1.5 m(3)/day of flushed swine manure was monitored under four different operational conditions for 7 months. The system consists of a Sequencing Batch Reactor (SBR) which was operated with 35 days solids retention time (SRT). Two hydraulic retention times (HRTs) (five day and ten day) were used with different aeration schemes, giving four different operational conditions. The ten day HRT had a short aeration cycle (1 hr on - 1 hr off) and a long cycle (4-6 hr on -4 hr off). The five day HRT used the short cycle (1 hr on - 1 hr off) and a medium cycle (2 hr on - 2 hr off). Concentration reductions varied with hydraulic retention time and aeration scheme used. Higher removals were observed when the SBR was operated with 10 days HRT and short aerating/non-aerating periods (aeration 1 hour on, 1 hour off) than with other conditions. The chemical oxygen demand (COD), volatile solids, and total nitrogen removals (93, 75, 95, respectively) were highest when the HRT was 10 d and the aeration cycle was short. The five day HRT enables a 50 reduction in reactor volume while still providing substantial removal of COD, volatile solids, and total nitrogen (86, 71, 81, respectively). About 25 of the influent volume was removed as biosolids. References: 48