Research On The Treatment Of Molasses Wastewater Using Anaerobic Baffled Reactor (ABR)

In order to achieve efficient processing for molasses wastewater of high concentration, the experiment was divided two periods using an ABR with four compartments and effective volume of 28.75 L. The first period, it summed up the operation characteristics of ABR in the start-up period and the influence to this system when infulent COD had a raise, through a phased approach to influent COD.The second period analyzed the infulence to the system when OLR had a change through a synchronous regulation of COD/HRT.After inoculated with a mixture of aerobic and anaerobic activated sludge, when the ABR system started up with a HRT of 24 h, influent pH ranged 7.0~8.2 under temperature 35℃, the influent COD concentration increased gradually from 570 mg·L-1 to about 5000 mg·L-1,the system reached stability amonge 93 days. At this point the COD removal rate reached 30% on average. Although the COD removal rate is not high, all indicators achieved a relatively stable scope under this conditions and four compartments all started to appear phase separation phenomenon. The flora can adapt to current environmental conditions and their growth was in good condition.Then influent COD concentration increased further to 6000 mg·L-1, and after running some time , trace metallic element was puted into ABR until the 151st day. At this time the COD removal rate reached 61%, the organic removal ability of ABR system was improved.To enhance performance of ABR further, this period could be divided four phases for COD/HRT synchronous regulation, they were HRT 24 h, COD 4000 mg·L-1, OLR 4 kg·m-3·d-1; HRT 36 h, COD 6000 mg·L-1, 4 kg·m-3·d-1; HRT 36 h, COD 8000 mg·L-1, OLR 5.4 kg·m-3·d-1; HRT 48 h, COD 8000 mg·L-1, OLR 4 kg·m-3·d-1. The results indicated that the regulation of influent COD concentration and HRT with the OLR ranged from 4 to 5.4 kg·m-3·d-1 could make all kinds of function flora that participated the anaerobic digestion process distribute more orderly in this ABR system, then the pollutant removal efficiency and the stability of the reactor were improved effectively. A COD removal rate above 90% had been achieved in the ABR under OLR 4 kg·m-3·d-1(HRT 48 h,COD 8000 mg·L-1), and at this phase methane content in every compartment reached 31%, 36%, 51% and 59%, on the contrary the CO2/H2 and acetic acid content decreased. Based on the analysis of flora activity in each compartment and biological observation, it was known that each kind of flora that participated in the anaerobic digestiong process had formed a phase separation characteristic in each phase of ABR, established a biological basic for an efficient and steady running of the system.