Efficient Purification And Recycling Of Mixed Food Wastewater Based On Microalgae Cultivation

In recent years,the application of microalgae in wastewater treatment has attracted extensive attention.There are a lot of organic matter,nitrogen,phosphorus and other nutrient elements in the wastewater,which can be used as potential microalgae culture medium.In addition,the use of microalgae can not only purify wastewater,but also accumulate a large amount of value-added biomass,environmental and economic benefits are significant.Among all kinds of wastewater,food industry wastewater has the advantages of high content of organic components,low toxicity and less harmful components.Therefore,the microalgal biomass cultivated from food wastewater has more added value.Considering the actual process,there are many different kinds of food waste water and characteristics of each different,this article tries to two different kinds of acid,alkali,organic matter content of different wastewater mixed microalgae cultivating thinking,in two typical food wastewater(soybean products wastewater and dairy wastewater)as the representative,to explore the mixed mode micro algae ability difference and the influence mechanism of purifying the wastewater,and compared the differences in culture,with a single food wastewater economically feasible for industrial applications of micro algae purification path.In this thesis,the purification ability of chlorete to single soybean products wastewater,single dairy products wastewater and mixed food wastewater was investigated.The results show that mixing the two in different proportions can significantly improve the harsh environment of a single wastewater,and generally improve the growth rate and purification capacity of chlorete.When the two are mixed in 1:1 ratio,biomass yield can reach the maximum value(2.20?4.27 g/L),which is 2?6times of the biomass of other mixed ratios.Meanwhile,the removal rates of total nitrogen,ammonia nitrogen,total phosphorus and COD in mixed wastewater were72.75%,65.97%,94.3% and 62.75%,respectively.In the later products,the contents of pigment,polysaccharide,carbohydrate oil and protein were 70.83 mg/L,117.00 mg/L,271.57 mg/L,337.45 mg/L and 2.03 g/L,respectively.In addition,in order to further improve the purification ability of chlococcus against mixed wastewater,this thesis also established a culture mode of "regular partial harvesting + supplementary algae seeds",which enhanced biomass yield,water quality purification effect and accumulation of value-added biological macromolecules.The results showed that the cumulative biomass under the new model increased by 0.60?1.08 g/L,and the contents of pigment,polysaccharide,carbohydrate and oil in the value-added products increased by 13.00?21.20 mg/L,26.65?72.24 mg/L,78.87?240.38 mg/L,and 192.50?276.91 mg/L,respectively.The experiment of microalgae culture in mixed wastewater showed that,in actual production,there was a potential synergy between mixing wastewater from food industry with different acidity,alkalinity and organic matter content and using microalgae to purify wastewater,which could improve resource recovery potential while purifying water quality.