Advanced Treatment Of The Garlic-sliced Wastewater By Carrier ABR-SBR Process

The amount of garlic production is very high in China, ranking first in the world, which is representing the world's total output of 1/4. Most of enterprises mainly processed on garlic slice. Sliced-garlic process produced a large amount of wastewater in the process of soaking, washing and centrifuging. The wastewater becomes a kind of refractory wastewater, because of the higher concentration of COD and allicin having a strong bactericidal effect.In this paper, the wastewater is studied with anaerobic and aerobic treatment process, the main contents are:1. Using Carrier Anaerobic Baffled Reactor (ABR) to treat garlic-sliced wastewater, and explore the best operation conditions.2. Aerobic treatment process chooses Sequencing Batch Reactor (SBR), using SBR to treat garlic-sliced wastewater, and explore the best operation conditions.3. Exploring the feasibility and effectiveness of carrier ABR-SBR process treating garlic-sliced wastewater in the best conditions.4. Exploring the feasibility and effectiveness of constructed wetland treating effluent of carrier ABR-SBR process.In this paper, results showed that:1. The optimum HRT of Carrier ABR was 20 hours,7.8 kgCOD/(m3-d) of the optimum organic load rate. The average removal rate of COD and BOD was 92.5% and 87%, respectively. ABR improves BOD/COD ratio from 0.31~0.35 to 0.52-0.59, and increases the biodegradability of wastewater.2. In the carrier ABR process, the average removal rate of TN was 4.1%; the highest removel rate of TP was 1.5%, and sometimes even in the negative.3. The optimum running condition of SBR was at the Aeration time 6 hours and the OLR 1.0 kgCOD/(m3-d), respectively, with the COD removal rate of 86.1%. The average concentration of the effluent COD and BOD was 120.7 mg/L and 41.2 mg/L, respectively, but effluent water cant't still meet the (GB8987-1996) "integrated wastewater discharge standard" first grade discharge standard.4. In the SBR process, the average removal rate of TN and TP was 79.9% and 69.2%, the average effluent concentration was 14.2-16.1mg/L and 1.9-2.5mg/L, respectively.5. The carrier ABR-SBR process run at the best conditions, the average removal rate of COD and BOD was 98.9% and 99.3%, the average effluent concentration was 65.7-70.8mg/L and 13.1-17.lmg/L, respectively. Combination process on the average removal rate of TN is 84.1%, the average effluent concentration was 11.1-12.6 mg/L. Combination system for TP removal rate was at 82%, far higher than the traditional process of phosphorus removal (traditional activated sludge was 60 percent), but also can ensure effluent below 1.5 mg/L. All of the effluent concentration can meet the (GB8987-1996) "integrated wastewater discharge standard" first grade discharge standard.6,The best HRT of constructed wetland treating combined process was 3.5 d, the effluent COD concentration of the combined process was 39.0 mg/L-42.1 mg/L, the effluent BOD concentration was 7.4 mg/L-8.9 mg/L, the effluent TN concentration was 5.4mg/L-6.0 mg/L and the effluent TP concentration was 0.41mg/L-0.50 mg/L, the pollutants concentration can meet the (GB18918-2002) "Discharge standard of pollutants for municipal wastewater treatment plant" first grade A discharge standard. The effluents can be used as landscape water and so on, making water resources. Constructed wetland as a follow-up treatment for the combined process is feasible on technology.