Ghazani Mostafa Tizghadam, Taghdisian Alireza
1Faculty of Civil, water and Environmental Engineering, Shahid Beheshti University, Tehran, Iran.
Environmental Engineering, Tehran, Iran.
J Biol Eng. 2019 Jul 29;13:64. doi: 10.1186/s13036-019-0192-1. eCollection 2019.
Significant rise in concentration of saline wastewater entering the treatment plants has been resulting in many problems in the biological treatment processes. On the other hand, the specific conditions of physicochemical treatment methods for saline and hyper saline wastewater have limited their application on a large-scale. Over the past few decades, Sequencing Batch Reactor (SBR) process has been widely used as an efficient, well-designed and practical approach for treatment of domestic and industrial wastewater due to its cost-effectiveness and simplicity. SBR Performance can enhance by providing simultaneous suspended and attached growth of microorganisms which act as a hybrid growth. In this study, a lab-scale Hybrid Sequencing Batch Reactor (HSBR) with 6.4 l working volume was used to examine the effect of salinity (NaCl), increased from 0 to 6.7% (g NaCl/ L wastewater), on the biological treatment. Therefore, COD, MLSS, MLVSS and SVI parameters have been measured over a period of 7 months of operation. The operational parameters namely pH, dissolved oxygen (DO) and temperature were 7.5-8.5, 1.5-6.8 mg /L and 20-25 °C respectively during whole experiment. Influent COD of synthetic wastewater was maintained at 650 ± 25 mg/L. The HSBR Cycle time including, influent feeding, React, Settling and effluent discharge were 1/20/1/1 h respectively. Results indicated that by increasing salt concentration from 0 to 67.7 g NaCl/L, the COD removal efficiency reduced from 94.22 to 53.69%. Moreover, as the NaCl concentration increased, MLSS rose up to 69%, while MLVSS almost stayed constant and SVI dropped by 83%. The results indicated that the simultaneous use of suspended and attached growth of microorganisms and gradual increasing of salt content of wastewater could lead to greater biomass concentration and ultimately improvement in the degradation of organic matter. Besides, settling performance and its velocity were noticeably improved by increasing salinity.
进入处理厂的含盐废水浓度显著上升，给生物处理过程带来了诸多问题。另一方面，含盐和高含盐废水的物理化学处理方法的特定条件限制了它们的大规模应用。在过去几十年中，序批式反应器（SBR）工艺因其成本效益高和操作简单，已被广泛用作处理生活污水和工业废水的一种高效、设计良好且实用的方法。通过提供微生物的同步悬浮生长和附着生长（即混合生长），SBR的性能可以得到提高。在本研究中，使用了一个工作体积为6.4升的实验室规模的混合序批式反应器（HSBR），来研究盐度（NaCl）从0增加到6.7%（克NaCl/升废水）对生物处理的影响。因此，在7个月的运行期间对化学需氧量（COD）、混合液悬浮固体（MLSS）、混合液挥发性悬浮固体（MLVSS）和污泥体积指数（SVI）参数进行了测量。在整个实验过程中，操作参数即pH值、溶解氧（DO）和温度分别为7.5 - 8.5、1.5 - 6.8毫克/升和20 - 25℃。合成废水的进水COD保持在650±25毫克/升。HSBR的循环时间包括进水、反应、沉淀和出水排放分别为1/20/1/1小时。结果表明，将盐浓度从0增加到67.7克NaCl/升时，COD去除效率从94.22%降至53.69%。此外，随着NaCl浓度的增加，MLSS上升了69%，而MLVSS几乎保持不变，SVI下降了83%。结果表明，同时使用微生物的悬浮生长和附着生长以及逐渐增加废水的盐含量可以导致更高的生物量浓度，并最终改善有机物的降解。此外，通过增加盐度，沉淀性能及其速度得到了显著改善。
