大薸对奶厅废水主要污染物的去除效果研究

Removal effect of Pistia stratiotes on major pollutants in milking parlor wastewater

为探索低成本高效率的奶厅废水处理新技术,本研究以大薸(Pistia stratiotes)为研究对象,选择某奶牛养殖场奶厅废水原水、厌氧处理后和好氧处理后的废水开展室内试验,重点研究大薸对奶厅废水中主要胁迫盐分的耐受浓度阈值,以及大薸对奶厅废水中基础养分(TN、TP、COD等)和阴离子盐(SO_(4)^(2-)、Cl^(-)等)的去除效果。结果表明:当奶厅废水的电导率未超过2193~2527μS·cm^(-1)时,大薸对奶厅废水中的盐分具有耐受性。但当奶厅废水中两种主要阴离子盐SO_(4)^(2-)和Cl^(-)含量分别超过5 mmol·L^(-1)和15~25 mmol·L^(-1)时,大薸抗氧化酶活性受到抑制。在净化三类奶厅废水的过程中,大薸对水体COD的削减作用最为明显,减少了65.51%~86.75%,TN、NH_(4)^(+)-N和TP含量分别降低了69.46%~87.52%、64.00%~96.59%和30.73%~66.02%,而SO_(4)^(2-)和Cl^(-)分别被大薸吸收了16.37%~18.04%和22.02%~35.83%。此外,大薸处理时间为23 d时,对奶厅废水原水和厌氧处理后的废水中多种污染物的去除效果最好。奶厅废水经厌氧处理后,大薸对多种污染物的削减作用更为明显,对水体中TN、NH_(4)^(+)-N、TOC、SO_(4)^(2-)和Cl^(-)的去除效果较原水分别提升了9.60%、42.83%、40.94%、2.00%和13.81%。研究表明,大薸对奶厅废水中盐分具有耐受性,且奶厅废水经厌氧处理后大薸可以更为有效地降低其中主要污染物含量。

To explore a novel method of milking parlor wastewater treatment with lower cost and more efficient purification effect,the present study conducted an indoor experiment using Pistia stratiotes for the purification of raw milking parlor wastewater or wastewater treated anaerobically or aerobically.The study focused on the tolerance concentration threshold of Pistia stratiotes to major salts in milking parlor wastewater as well as its removal effect on basic nutrients,such as total nitrogen(TN)and total phosphorus(TP),chemical oxygen demand(COD),and anionic salts,such as SO_(4)^(2-)or Cl^(-),in wastewater following purification.Pistia stratiotes was tolerant of major salts in milking parlor wastewater when the electrical conductivity of raw wastewater was below 2193-2527μS·cm^(-1).However,the activities oantioxidant enzymes in Pistia stratiotes were inhibited when the SO_(4)^(2-)and Cl^(-)levels exceeded 5 mmol·L^(-1)and 15~25 mmol·L^(-1),respectively.During purification of the three types of milking parlor wastewater,Pistia stratiotes produced the strongest reducing effect on COD,resulting in 65.51%-86.75%less of the substance in wastewater.TN,NH_(4)^(+)-N,and TP decreased by 69.46%-87.52%,64.00%-96.59%,and 30.73%-66.02%,respectively,while SO_(4)^(2-)and Cl^(-)levels decreased by 16.37%-18.04%and 22.02%-35.83%,respectively.Additionally,Pistia stratiotes produced the best removal effects on many pollutants in raw and anaerobically treated wastewater for 23 days.Specifically,the removal effect of Pistia stratiotes on TN,NH_(4)^(+)-N,total organic carbon,SO_(4)^(2-),and Cl^(-)was improved by respectively 9.60%,42.83%,40.94%,2.00%,and 13.81%in anaerobically treated wastewater compared with that in raw wastewater.Therefore,Pistia stratiotes is tolerant of major salts in milking parlor wastewater,and plant purification can effectively reduce primary pollutants levels in this type of wastewater following anaerobic treatment.