Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, 90014 University of Oulu, Finland.
J Environ Sci (China). 2013 Apr 1;25(4):659-69. doi: 10.1016/s1001-0742(12)60111-9.
The drainage of peatland areas for peat extraction, agriculture or bioenergy requires affordable, simple and reliable treatment methods that can purify waters rich in particulates and dissolved organic carbon. This work focused on the optimisation of chemical purification process for the direct dosage of solid metal salt coagulants. It investigated process requirements of solid coagulants and the influence of water quality, temperature and process parameters on their performance. This is the first attempt to provide information on specific process requirements of solid coagulants. Three solid inorganic coagulants were evaluated: aluminium sulphate, ferric sulphate and ferric aluminium sulphate. Pre-dissolved aluminium and ferric sulphate were also tested with the objective of identifying the effects of in-line coagulant dissolution on purification performance. It was determined that the pre-dissolution of the coagulants had a significant effect on coagulant performance and process requirements. Highest purification levels achieved by solid coagulants, even at 30% higher dosages, were generally lower (5%-30%) than those achieved by pre-dissolved coagulants. Furthermore, the mixing requirements of coagulants pre-dissolved prior to addition differed substantially from those of solid coagulants. The pH of the water samples being purified had a major influence on coagulant dosage and purification efficiency. Ferric sulphate (70 mg/L) was found to be the best performing solid coagulant achieving the following load removals: suspended solids (59%-88%), total organic carbon (56%-62%), total phosphorus (87%-90%), phosphate phosphorus (85%-92%) and total nitrogen (33%-44%). The results show that the use of solid coagulants is a viable option for the treatment of peatland-derived runoff water if solid coagulant-specific process requirements, such as mixing and settling time, are considered.
为了进行泥炭开采、农业或生物能源开发而排干泥炭地需要负担得起、简单且可靠的处理方法，这些方法能够净化富含颗粒物和溶解有机碳的水。本研究专注于优化直接投加固体金属盐混凝剂的化学净化工艺。研究了固体混凝剂的工艺要求以及水质、温度和工艺参数对其性能的影响。这是首次尝试提供有关固体混凝剂具体工艺要求的信息。评估了三种固体无机混凝剂：硫酸铝、硫酸铁和聚合硫酸铁。还测试了预溶解的硫酸铝和硫酸铁，目的是确定在线混凝剂溶解对净化性能的影响。结果表明，混凝剂的预溶解对混凝剂性能和工艺要求有重大影响。即使投加量增加 30%，固体混凝剂所能达到的最高净化水平（5%-30%）通常也低于预溶解混凝剂的水平。此外，预溶解混凝剂的添加混合要求与固体混凝剂有很大不同。待净化水样的 pH 值对混凝剂投加量和净化效率有重大影响。硫酸铁（70mg/L）是表现最佳的固体混凝剂，可实现以下去除率：悬浮物（59%-88%）、总有机碳（56%-62%）、总磷（87%-90%）、正磷酸盐（85%-92%）和总氮（33%-44%）。结果表明，如果考虑固体混凝剂的特定工艺要求，例如混合和沉降时间，那么固体混凝剂是处理泥炭地径流水的可行选择。
