【作者】 张航；

【导师】 杨岳平；

【作者基本信息】 浙江大学 ， 环境工程， 2020， 硕士

【摘要】 我国生活饮用水面临着水源易受污染、二次污染等问题,伴随着人们对身体健康和生活品质需求的不断提高,饮用水水质不足以完全满足居民对水质的要求。我国居民饮用水的水质差别较大,针对不同类别的水质需采用不同的深度处理技术,通过调整工艺或参数使处理效果最优化。本论文在对国内外权威饮用水标准进行对比研究的基础上,选择了10项常见水质指标作为后续调研和深度处理试验的研究指标。通过对我国典型城市生活饮用水水质进行调研,对所选水质指标浓度进行测定,总结我国不同地区水质特征,为后续深度处理试验提供指标浓度参考。单级活性炭吸附试验:通过试验研究,优化操作条件,确定滤速为23.4 m/h。在此基础上,单级活性炭吸附效率试验设定指标进水初始浓度为国标限值的0.3倍、0.7倍、1倍、1.3倍、1.7倍。六价铬的去除率为51.98～62.19%,最低出水浓度比国标限值降低了30～60%;镉离子的去除率为20.96～58.88%,最低出水浓度比国标限值降低了20～55%;铅离子的去除率为33.41～78.34%,最低出水浓度比国标限值降低了45～75%;三氯甲烷的去除率为59.70～83.57%,最低出水浓度比国标限值降低了35～75%;六六六、滴滴涕的去除率都在97～100%。纳滤深度处理试验:通过试验研究,优化操作条件,确定进水流量为3 L/min、操作压力为0.5MPa及纳滤膜型号。在此基础上纳滤去除试验设定指标进水初始浓度为国标限值的0.3倍、0.7倍、1倍、1.3倍、1.7倍。硝酸盐氮的去除率为43.28～56.06%,最低出水浓度比国标限值降低了15～55%;六价铬的去除率为64.71～87.50%,最低出水浓度比国标限值降低了75～85%;铅离子的去除率为62.50～91.23%,最低出水浓度比国标限值降低了75～80%;镉离子的去除率为56.25～83.95%,最低出水浓度比国标限值降低了45～50%;三氯甲烷的去除率为71.03～84.96%,最低出水浓度比国标限值降低了55～85%;六六六的去除率为71.94～84.37%,最低出水浓度比国标限值降低了75～80%;滴滴涕的去除率为61.76～75.41%,最低出水浓度比国标限值降低了55～80%;对于总硬度及钙镁离子,处理后能稳定保持在标准限值范围内。饮用水深度处理工艺组合:1)PP棉-颗粒活性炭-颗粒活性炭-压缩活性炭-超滤膜组合工艺分别处理含有重金属、有机物、重金属和有机物复合类型的饮用水,含有重金属的饮用水后续出水中出现镉离子达不到浓度限值0.003 mg/L的情况;六价铬最高去除率可达到76%,随着时间增加去除效果逐渐降低,但始终在推荐浓度限值0.05 mg/L以下;铅离子最高去除率可达到61%,随着时间增加去除效果逐渐降低,但始终在推荐浓度限值0.01 mg/L以下。含有有机物的饮用水后续出水中三氯甲烷最高去除率可达到67.4%,随着时间增加去除效果逐渐降低,但始终在推荐浓度限值0.06 mg/L以下;六六六、滴滴涕最高去除率接近100%,后续出水浓度始终在推荐浓度限值以下。对于复合类型饮用水,活性炭组合工艺去除浓度在1.7倍国标限值附近的重金属效果相比较差。2)PP棉-颗粒活性炭-纳滤膜(NF1)-超滤膜组合工艺分别处理硝酸盐氮超标、高硬度的饮用水、含有重金属和有机物的高硬度复合类型饮用水。出水中的硝酸盐氮浓度均低于10 mg/L,硝酸盐氮的去除率并未随着纳滤运行时间降低,始终保持在29%～51%范围内,处理后比标准限值低30～50%。对于高硬度饮用水,出水中硬度及钙镁离子能达到建议浓度范围,但其去除率会随着工艺的运行时间降低。对于复合类型饮用水,出水中六价铬的去除率保持在10%～34%范围内,铅、镉的浓度超过试验指标的浓度限值,对重金属处理效果不佳;三氯甲烷、六六六、滴滴涕的去除率分别保持在26.9%～64%、25%～100%、15%～84%范围内,分别比对应标准限值低30～60%、25%、15%～80%。两种工艺组合相比,含有纳滤的工艺组合更适合去除硝酸盐氮、降低水的硬度。对于含有多种指标的复合类型饮用水,需采用反渗透工艺,进一步脱盐和提高毒理性指标去除率。根据上述试研究结果,设计一款以纳滤工艺为主的家用净水器,并进行成本核算。更多还原

【Abstract】 In our country,drinking water is facing few issues including source vulnerable in pollution,secondary pollution.The drinking water quality is not satisfied with residential demand anymore,along with raising living needs in body health and life quality.The drinking water quality has a large difference across the country,different advanced water treatment techniques with modified methods and parameters are required in specific to different types of water in ensuring to achieve the best outcome.Based on a comparative study of authoritative drinking water standards at home and abroad,this paper selects 10 common water quality indicators as research indicators for follow-up investigation and advanced treatment tests.Through the investigation of the drinking water quality of typical cities in our country,the concentration of selected water quality indicators was measured,and the characteristics of water quality in different regions of our country were summarized to provide concentration references for subsequent advanced treatment tests.Single-stage activated carbon adsorption test: Through experimental research,the operating conditions are optimized and the filtration rate is determined to be 23.4m/h.On this basis,the single-stage activated carbon adsorption efficiency test sets the initial concentration of the influent water to be 0.3 times,0.7 times,1 time,1.3 times,and 1.7 times the national standard limit.The removal rate of hexavalent chromium is51.98～62.19%,and the minimum effluent concentration is 30～60% lower than the national standard limit;the removal rate of cadmium ions is 20.96～58.88%,and the minimum effluent concentration is 20～55% lower than the national standard limit.The removal rate of lead ions is 33.41～78.34%,and the minimum effluent concentration is45～75% lower than the national standard limit;the removal rate of chloroform is59.70～83.57%,and the minimum effluent concentration is 35～75% lower than the national standard limit;The removal rate of BHC and Dichlorodiphenyltrichloroethane is 97～100%.Nanofiltration advanced treatment test: Through experimental research and optimization of operating conditions,it is determined that the inlet water flow rate is 3L/min,the operating pressure is 0.5MPa and the nanofiltration membrane model.On this basis,the single-stage activated carbon adsorption efficiency test sets the initial concentration of the influent water to be 0.3 times,0.7 times,1 time,1.3 times,and 1.7times the national standard limit.The removal rate of nitrate nitrogen is 43.28～56.06%,the minimum effluent concentration is 15～55% lower than the national standard limit;the removal rate of hexavalent chromium is 64.71～87.50%,and the minimum effluent concentration is 75～85% lower than the national standard limit;the removal rate of lead ions is 62.50～91.23%,the minimum effluent concentration is 75～80% lower than the national standard limit;the removal rate of cadmium ions is 56.25～83.95%,and the minimum effluent concentration is 45～50% lower than the national standard limit;The removal rate of chloroform is 71.03～84.96%,the minimum effluent concentration is55～85% lower than the national standard limit;the removal rate of BHC is71.94～84.37%,and the minimum effluent concentration is 75～80% lower than the national standard limit;the removal rate of Dichlorodiphenyltrichloroethane is61.76～75.41%,and the minimum effluent concentration is 55～80% lower than the national standard limit;for the total hardness and calcium and magnesium ions,it can be stably maintained within the standard limit after treatment.Combination of advanced drinking water treatment process: 1)PP cotton-granular activated carbon-granular activated carbon-compressed activated carbon-ultrafiltration membrane combined process respectively treats drinking water containing heavy metals,organics,heavy metals and organic compounds,and in the subsequent effluent of drinking water containing heavy metals Cadmium ions do not reach the concentration limit of 0.003 mg/L;the maximum removal rate of hexavalent chromium can reach 76%,and the removal effect gradually decreases with the increase of time,but it is always below the recommended concentration limit of 0.05 mg/L;The highest ion removal rate can reach 61%,and the removal effect gradually decreases with time going,but it is always below the recommended concentration limit of 0.01 mg/L.The maximum removal rate of trichloromethane in the subsequent effluent of drinking water containing organic matter can reach 67.4%,and the removal effect gradually decreases with time going,but it is always below the recommended concentration limit of 0.06mg/L;the maximum removal rate of BHC and Dichlorodiphenyltrichloroethane is close to 100%,the subsequent effluent concentration is always below the recommended concentration limit.For composite drinking water,the combined activated carbon process has a relatively poor effect on removing heavy metals whose concentration is around 1.7 times the national standard limit.2)PP cotton-granular activated carbonnanofiltration membrane(NF1)-ultrafiltration membrane combined process separately treats drinking water with excessive nitrate nitrogen,high hardness,and high hardness composite drinking water containing heavy metals and organics.The concentration of nitrate nitrogen in the effluent is less than 10 mg/L,and the removal rate of nitrate nitrogen has not decreased with the running time of nanofiltration,and has always remained within the range of 29%～51%,which is 30%～50% lower than the standard limit after treatment.For high-hardness drinking water,the hardness and calcium and magnesium ions in the effluent can reach the recommended concentration range,but the removal rate will decrease with the running time of the process.For composite drinking water,the removal rate of hexavalent chromium in the effluent is maintained within the range of 10% to 34%,and the concentration of lead and cadmium exceeds the concentration limit of the test index,which is not effective in treating heavy metals.The removal rates of chloroform,BHC and Dichlorodiphenyltrichloroethane were maintained within the ranges of 26.9%～64%,25%～100%,15%～84%,respectively,which were 30～60%,25% and 15%～80% lower than the corresponding standard limits.Compared with the two process combinations,the process combination containing nanofiltration is more suitable for removing nitrate nitrogen and reducing water hardness.For composite drinking water containing multiple indicators,reverse osmosis technology is required to further desalinate and improve the removal rate of toxicological indicators.Based on the above-mentioned trial research results,a household water purifier based on nanofiltration technology was designed and cost accounting was performed.更多还原