Preparation Of Bioflocculant Using Digested Piggery Wastewater As Substrate

Microbial flocculant is a kind of secondary metabolite produced by microbe, it isefficient, safe, and can be degraded in the natural conditions, more and more arousedpeople’s wide attention, but the high cost of production has restricted the scaleapplication of microbial lfocculants, so looking for some cheap substrate which canreplace carbon source, nitrogen source of culture medium, reduced the cost of culturemedium. It has an important significance for the large-scale production of biologicallfocculating.Piggery wastewater including pig urine, pig manure, and rinse water. It have highconcentration of organic matter （COD4.0?10.0g/L）, and high ammonia nitrogen andtotal nitrogen content （0.3?5.0g/L ammonia nitrogen）,total nitrogen （0.6?2.3g/L）.It isdifficult to treat as a kind of organic wastewater, but piggery wastewater can providenitrogen source for the growth of microbe. This study chooses Rhodococcuserythropolis as flocculant producing microorganisms, using piggery wastewater byanaerobic treatment as substrate. Through studying the effects of carbon source,nitrogen source, phosphorus source and initial pH value on bioflocculant production,this research investigated the production of bioflocculant by Rhodococcuserythropolis using the piggery wastewater by anaerobic treatment as substrate.Meanwhile, through studying the effect of variety factors on the lfocculation rate aswell as the degree by orthogonal experiment, the optimized medium was ensured.Then harvested and identified the microbial flocculant in the fermented liquid. At last,through qualitative and quantitative determination of microbial flocculant about thedosage, pH，Ca²⁺，and other metal ions to ifnd influence on microbial lfocculants. Thiscan provide theoretical for microbial lfocculant scale and industrial application.By measuring the composition in the piggery wastewater by anaerobic treatmentfound that anaerobic digestive juices contains abundant nitrogen source, carbonsource is relatively. It can be used for Rhodococcus erythropolis as the cheap mediumby join a certain amount of carbon source, and phosphate in the piggery wastewater byanaerobic treatment. When the composition of the piggery wastewater medium is asfollows: piggery wastewater1.0L，sucrose10g/L, KH₂PO₄2.0g/L, K2HPO45.0g/L,NaCl1.0g/L, MgSO₄0.2g/L. And after72hrs of cultivation under the condition of30。C，120r/min and the medium pH of8.0，the flocculating rate can reach92.57%. This is concluded that the piggery wastewater can be used as an effective andlow-cost substrate on bioflocculant production by adding the right amount of sucroseand phosphate.MBF produced by Rhodococcus erythropolis mainly exist in the fermented liquid,belonged to extracellular flocculant. The main ingredient of the MBF is proteins andnucleic acids. The dosing quantity of MBF is2ml/100ml in the actual treatment ofkaolin suspensions. The MBF is better than inorganic lfocculant at the effect andspeed about the flocculate.