广西封闭式海水养殖尾水污染排放特征及防治对策研究

A study on the characteristics of pollution discharge and prevention countermeasures of closed mariculture tailwater in Guangxi

关键词:  封闭式海水养殖  尾水  排放特征  防治对策

Key words:  closed mariculture  tailwater  emission characteristics  prevention countermeasures

摘要:

于2021年对广西沿海主要海水养殖区的池塘养殖、工厂化和育苗场三种封闭式养殖方式的养殖尾水进行了大范围监测,共布设102个站位次,对比分析不同养殖方式、养殖类型尾水中主要污染物pH、SS、COD、TN、DIN、TP和DIP的浓度特征,采用广西地方标准《海水养殖尾水排放标准》一级标准、内梅罗综合指数(P)、营养状态质量指数(NQI)等开展尾水污染状况的综合评价。结果表明,三种养殖方式的尾水主要污染物平均浓度和超标率大小均呈现池塘＞育苗场＞工厂化,池塘养殖各类型中尾水主要污染物平均浓度和超标率大小呈现单养虾＞混养＞单养鱼＞单养蟹。养殖尾水的P值、NQI 值处于重度污染和富营养化等级的养殖点位比例分别为57.8%、66.7%,池塘养殖中单养虾的重度污染和富营养化等级占比最高,工厂化无重污染等级且富营养比例最低。封闭式海水养殖尾水的排污强度与各养殖场的养殖方式、养殖品种、养殖密度、养殖技术和尾水治理设施有关,养殖尾水治理应针对不同养殖方式和类型的污染特点进行分类防治,重点关注高密度、排水率高的高位池及小棚式池塘养殖。

Abstract:

We monitored the tailwater of three sealed mariculture types, including pond, factory, and nursery, in 2021 with total of 102 records. The concentration characteristics of the main pollutants pH, SS, COD, TN, DIN, TP and DIP in the tailwater of different periods were comparative analyzed. The Guangxi local standard "Discharge standard of tailwater for mariculture" level 1 standard, Nemerow index (P), and Nutrient Quality index (NQI) were used to carry out a comprehensive evaluation of the pollution status of the tailwater. The results showed that the average concentration and exceeding rate of the main pollutants in the tail water of the three types of aquaculture were pond > nursery > factory, and the average concentration and exceeding rate of the main pollutants in the tailwater of each type of pond aquaculture showed that mono-culture of shrimp > mix-culture > mono-culture of fish > mono-culture of crab.The proportion of aquaculture sites where the P and NQI indexes of the culture tail water were in the heavy pollution and eutrophication classes was 57.8% and 66.7%, respectively, and the proportion of heavy pollution and eutrophication classes of monoculture shrimp was the highest in pond culture, and the proportion of factory was the lowest with no heavy pollution class and eutrophication. The discharge intensity of closed mariculture tailwater is related to the culture mode, culture species, culture density, culture technology and tailwater management facilities of each farm. The management of aquaculture tailwater should be categorized and prevented according to the pollution characteristics of different culture modes and types, with a focus on high-density, high-drainage-rate high ponds and small-shed-type pond culture.