| Potato starch production wastewater is rich in plant nutrients such as nitrogen,phosphorus and potassium,and direct discharge or simple treatment will lead to environmental pollution and waste of resources.At present,some farmers use this type of wastewater directly for farmland irrigation,because it contains a large amount of oxygen-consuming organic matter,which leads to changes in soil physical and chemical indicators,which weakens farmland fertility,causes seedling burning,and reduces crop yield.Therefore,in view of the above problems,this study uses potato starch production wastewater degradation bacteria to degrade macromolecular organic matter in wastewater into small molecule nutrients that can be directly used by plants,shorten the process of field ripening after wastewater irrigation,which is expected to solve the negative problems caused by direct irrigation of wastewater.The results of wastewater fertilizer efficiency test showed that potato starch production wastewater had fertilizer function,and the suitable dilution ratio of wastewater irrigation was conducive to the accumulation of soil organic matter,available phosphorus,and available nitrogen,which helped the growth of seedling stems and leaves in the short term,but long-term used of wastewater irrigation,the soil was prone to acidification,and it affected the development of plant roots.The results of single bacterial degradation experiments showed that Acinetobacter and Bacillus could well degrade soluble proteins in potato starch production wastewater,shorten the ripening time of wastewater,and degraded wastewater by Acinetobacter and Bacillus for 48 hours to make the content of ammonia nitrogen in wastewater reach 174.16 and138.18 mg/L,respectively,and the content of ammonia nitrogen could reach 8 times and 6times that of ammonia nitrogen in raw water,respectively,greatly increasing the concentration of soluble nitrogen in wastewater;at the same time,the soluble phosphorus concentration in wastewater could be maintained at 19.52 and 13.14 mg/L,respectively;the biomass of bacteria in 48 hours fermentation wastewater were 1.56×10~9and 1.68×10~9cfu/m L,respectively,which met the national standard of liquid bacterial fertilizer(≥2.00×10~8 cfu/m L);the results showed that Acinetobacter was more suitable for low temperature,acidic environment and high concentration starch wastewater;Bacillus was more suitable for high temperature,neutral environment,low concentration starch wastewater.The experiments of mixed bacteria fermentation showed that the ammonia nitrogen production effect of mixed bacteria was significantly better than that of single bacteria fermentation,which could accelerate the degradation rate of soluble protein,the concentration of soluble phosphorus and ammonia and nitrogen fluctuated less,the overall fermentation effect was more stable,the p H and temperature ecological amplitude were widened,the problems of single bacteria fermentation were improved to different degrees,and the degradation rate of soluble protein could be improved in a short time,thus reducing the risk of irrigating farmland with potato starch production wastewater.The experimental results of bacterial fertilizer planting showed that watering bacterial fertilizer could improve the root development of plants,and the growth was significantly better than that of the control group;at the same time,the contents of soil organic matter,available phosphorus,available potassium and available nitrogen were significantly increased,which could be increased by 29.55%,94.79%,356.37%and 16.92%,respectively;it could increase the abundance of soil microbial dominant species,and soil bacteria,actinomycetes and fungi could be increased by 0.90,0.41 and 0.59 times,respectively;it could improve the acidification phenomenon of soil to a certain extent.Overall,it was beneficial to the improvement of soil quality and promoted the improvement of soil fertility. |
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