Karami Samira, Farzadkia Mahdi, Kermani Majid, Kalantary Roshanak Rezaei, Pasalari Hasan
Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran.
Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
Sci Rep. 2024 Apr 23;14(1):9308. doi: 10.1038/s41598-024-58821-1.
Over the recent years, ever-increasing population growth and higher wastewater production has been a challenge for decentralized wastewater treatment plants (WWTPs). In addition, sludge treatment due to high cost for equipment and place make authorities to find a sustainable approach in both of economical and technical perspectives. One of the proposed solutions is transferring the sludge produced from decentralized WWTP to centralized WWTP. However, the appropriate proportional ratio of raw sludge to raw sewage is a challenge, otherwise, it make anaerobic conditions and sewage rotting along the sewer network based on permissible limit of dihydrogen sulfide (HS) gas (5 ppm). In the present study, seven reactors with different ratios of sludge to raw sewage (0, 15, 20, 25, 50, 75, 100) were used to stimulate the feasibility of transferring Shahrake Gharb WWTP sludge along the wastewater transfer pipe to the centralized sewage treatment south Tehran WWTP plant in Tehran, Iran. The septic situation and HS emission of different reactors within 7 h (Time to reach the compound in the south treatment plant) was analyzed by gas meter. The results indicated that the optimum ratio of sludge to raw sewage was 15% without HS production during 7 h. In addition, due to the high volume of sludge produced by the Shahrake Gharb WWTP, the optimal ratio of lime to total solids (TS) in sludge (gr/gr) (0.6) increased the sludge loading rate from 15 to 30% without any HS emission during the stimulation study period. Therefore, the lime stabilization and transfer of sludge from a decentralized WWTP to a centralized WWTP is a feasible way to manage the sludge and enhance the treatment capacity in local WWTP.
近年来，人口增长不断加快以及废水产量不断增加，给分散式污水处理厂带来了挑战。此外，由于设备和场地成本高昂，污泥处理促使当局从经济和技术角度寻找可持续的方法。提出的解决方案之一是将分散式污水处理厂产生的污泥转移到集中式污水处理厂。然而，原污泥与原污水的合适比例是一个挑战，否则，根据硫化氢（HS）气体的允许限值（5 ppm），会导致厌氧条件以及污水在下水道网络中腐烂。在本研究中，使用了七个污泥与原污水比例不同（0、15、20、25、50、75、100）的反应器，来模拟将伊朗德黑兰Shahrake Gharb污水处理厂的污泥沿着废水输送管道转移到德黑兰南部集中式污水处理厂的可行性。通过气体计量仪分析了不同反应器在7小时内（到达南部处理厂中该化合物的时间）的腐败情况和HS排放。结果表明，污泥与原污水的最佳比例为15%，在7小时内无HS产生。此外，由于Shahrake Gharb污水处理厂产生的污泥量很大，在模拟研究期间，污泥中石灰与总固体（TS）的最佳比例（克/克）（0.6）将污泥负荷率从15%提高到了30%，且无任何HS排放。因此，将分散式污水处理厂的污泥进行石灰稳定化处理并转移到集中式污水处理厂，是管理污泥并提高当地污水处理厂处理能力的可行方法。
