Optimization And Research Of Several Unit Operations In Urine Source Separation System

Urine is the main excretion of human metabolism,it contains a lot of nutrients.Although it only accounts for 1%of treatment capacity of sewage treatment plants,it contributes about 80%of N,50%of P and 90%of K.Therefore,from concept of ecological sanitation and resource reuse,using urine source separation to collect urine separately can not only reduce nutrition load of sewage treatment plant,reduce treatment process of sewage treatment plant,but also reduce clean water for toilet flushing.It is also possible to reuse nutrients of urine after collection.At present,study of urine source separation has attracted attention of relevant experts at home and abroad,but finding a more economical,effective and pollution-free source for treatment of urine is still the focus of research at home and abroad.This study focuses on stabilization and further processing after urine collection,complements and optimizes existing urine processing systems.Urea accounts for 90-95%of total nitrogen in fresh urine and is a major target for urine treatment and recycling.However,urea is easy to be hydrolyzed by urease in the process of urine collection and storage,ammonia and carbamate produced will lead to pipeline clogging,resulting in ammonia nitrogen loss and bad odor,therefore,urease activity must be inhibited to prevent urea hydrolysis.By studying the effects of some common drugs in life and urine on enzyme activity,we found an economical and environmentally friendly method of urine stabilization,that is,while stabilizing urine,it can also recycle high-concentration drugs in hospital tail water.The results showed that inhibition rates of 1,2,4-benzenetriol,hydroquinone,catechol and disulfiram on urease activity were all above 97%,which could stabilize the urine for more than 31 days.The results of drug's inhibition of urease activity indicate that drug can effectively inhibit hydrolysis of urea,thereby affecting existing forms of nitrogen nutrients in urine.This work paves the way for more cost-effective stabilization of fresh urine and treatment of high-concentration drugs in hospital sewage up the road.At present,research on the treatment of nutrients in source-separated urine is also maturing.Ammonia stripping is widely used in wastewater pretreatment.This study,a stripping-hydrocyclone combined method is used to treat urine.By changing gas-liquid ratio,temperature and pH to determined optimal processing conditions.Considering cost and removal rate,the best parameters for removing NH3-N from urine using air stripping-hydrocyclone system are pH 10,gas-liquid ratio 1200,temperature 60?,removal rate is 93%after 3 h.And analyzed the life cycle effect of stripping-hydrocyclone system to obtain 1 g of NH4Cl under different gas-liquid ratio,pH and temperature,and found that increasing temperature can appropriately reduce impact of the whole process on environment.In addition,the recovery of urea in urine was studied by activated carbon adsorption method,and it was found that 0.8 mm spherical activated carbon had best adsorption effect on urea among the several kinds of activated carbon studied,11.8 mg/g.The kinetic and thermodynamic characteristics and adsorption effect after multiple adsorption and desorption,the results show that after five times of activated carbon regeneration and adsorption with clean water,its adsorption efficiency can still reach 80%or more.