| As the sewage treatment plant nitrification system is more vulnerable to high temperature,low temperature,high ammonia nitrogen and other factors,so enrichment of nitrification sludge helps to cope with the sudden collapse of the nitrification system is necessary.And high temperature is one of the factors that seriously affect the nitrification system.Especially when the temperature of inlet water is high in summer,and the temperature of wastewater in chemical industry and petroleum industry is very high,it will impact the nitrification system of sewage treatment plant.Therefore,it is necessary to study nitrification sludge high temperature characteristics.In this experiment,membrane bioreactor(MBR)was used to enrich the nitrification sludge.The culture medium is composed of waste water,ammonia nitrogen stock solution and alkalinity adjusting liquid.Enrichment was carried out by increasing the volume load of ammonia nitrogen step by step and studied the effects of temperature,demand oxygen,ammonia nitrogen load and other factors on the enrichment of nitrifying sludge.The production of nitrifying bacteria was calculated by the kinetic equation of activated sludge reaction,and the cost and benefit of nitrifying sludge enrichment were calculated.Finally,the reactor was operated under the condition of 1.5 kg N/(m3·d)ammonia load,the nitrification activity was 62.5 mg/(L·h)and the concentration of nitrifying bacteria was 1.29 g.After stabilizing the front of the reactor,it was adjusted to produce 64.5 g nitrifiers/d of nitrified sludge at SRT = 20 days.In order to enrich the nitrifying sludge that can be adapted to the high temperature environment,10L of nitrifying sludge was extracted from the medium temperature enrichment device and enriched culture was carried out at 30 ?,35 ?,40 ? and 45 ? respectively.In this experiment,the nitrification process of nitrification sludge was severely inhibited at 45 ?.However,the ability of nitrification sludge to degrade ammonia nitrogen was still good at 40 ?,and could basically maintain above 90%.Finally,the reactor resulted in a stable nitrification system at 40 ?.Through high?throughput sequencing analysis,it was found that nitrosomonas in nitrifying sludge at high temperature was higher than in common biochemical pool activated sludge,accounting for about 3%.The highest concentrations of acinetobacter and pseudomonas in the entire colonies of nitrifying sludge were 22%and 18%,respectively.In order to study the enhancement of the nitrification system collapse in the wastewater treatment plant by enrichment of nitrifying sludge and high-temperature nitrifying sludge respectively,a nitrification enhancement test was carried out.First,the number of dosing from the comparison of mesophilic nitrification sludge and high temperature nitrification sludge on the deterioration of the nitrification reactor biofortification,After adding 1%nitrifying sludge each,it was found that neither mesophilic enrichment nitrifying sludge nor high temperature enriching nitrifying sludge had a complete strengthening effect on the deteriorating reactor.Then the dosage of nitrifying sludge was increased,the results showed that the ability of nitrification system to remove ammonia nitrogen was increased by 40 mg/(L d)when the dosage of mesophilic nitrification sludge was 10%.However,the dosage of high-temperature nitrification sludge was 5%,the ability of nitrification system to remove ammonia nitrogen was increased by 30 mg/(L d).After adding 10%high-temperature nitrification sludge,the ability of nitrification system to remove ammonia nitrogen was improved by 40 mg/(L·d).In general,the greater the dosage of enriched nitrification sludge,the less the difference between the intensification effect of medium?temperature enriched sludge and high?temperature enriched sludge,and the addition of medium-temperature sludge for strengthening is more economical. |
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