类芬顿调理污泥用于微生物电解池产氢与磷回收的研究

为提高微生物电解池(MEC)利用剩余污泥产氢气和磷回收的效率,采用Fe~(3+)、原儿茶酸(PCA)和H_2O_2体系预调理污泥,探究中性PCA/Fe~(3+)/H_2O_2体系的试剂投加量对污泥液相总磷含量和溶解性化学需氧量(SCOD)的影响.在单因素试验的基础上,通过表面响应法(RSM)优化得到Fe~(3+)和H_2O_2投加量分别为12.96 mmol·L~(-1)和0.45 mol·L~(-1),液相总磷含量和SCOD含量实际值分别为(60.14±0.08) mg·L~(-1)和(3357.67±66.37) mg·L~(-1),模拟效果显著.与未处理的剩余污泥MEC反应器出水相比,经过调理后的剩余污泥MEC反应器出水中的总化学需氧量(TCOD)、多糖和蛋白质的去除率分别提高了30.03%、50.16%和97.31%,氢气转化率提升了1.31倍,有效提升了MEC产氢效率.通过鸟粪石结晶回收MEC污泥上清液中的磷,发现在初始pH值为10、Mg~(2+)浓度为0.056 mol·L~(-1)和NH~+_4浓度为0.08 mol·L~(-1)时效果最佳.鸟粪石晶体质量浓度最高可达7.6 g·L~(-1),晶体纯度最大为88.30%,上清液中77.55%的磷以鸟粪石的形式得到回收.在本研究最优化条件下进行中性PCA/Fe~(3+)/H_2O_2体系调理剩余污泥微生物电解池产氢与磷回收全过程中产出经济价值达到2.36元.实验研究最终表明,经过Fe~(3+)/PCA/H_2O_2体系调理污泥可促进污泥中磷的释放和MEC处理污泥的产氢效率,为探究污泥资源化提供了新的研究思路.

Study on Fenton-like conditioning of sludge for hydrogen production and phosphorus recovery in microbial electrolysis cells

In order to improve the efficiency of hydrogen production and phosphorus recovery from excess sludge in microbial electrolysis cell (MEC), sludge was pretreated with Fe³⁺, protocatechuic acid (PCA) and H₂O₂. The effects of reagent dosage of PCA/Fe³⁺/H₂O₂ under neutral condition on the total phosphorus content and dissolved chemical oxygen demand (SCOD) in sludge liquid phase were investigated by single factor test. The dosages of Fe³⁺ and H₂O₂ were optimized by surface response method (RSM), with optimized values of 12.96 mmol·L^-1 and 0.45 mol·L^-1 respectively. The actual values of total phosphorus and SCOD in liquid phase were (60.14 ±0.08) mg·L^-1 and (3357.67±66.37) mg·L^-1, respectively, achieving obvious improvement with the optimized simulated parameters. Compared with the untreated effluent from the residual sludge MEC reactor, the removal rates of total chemical oxygen demand (TCOD), polysaccharide and protein in the sludge treated by MEC were increased by 30.03%, 50.16% and 97.31%, respectively. The hydrogen conversion rate was increased by 1.31 times, and the hydrogen production efficiency of MEC was also improved. Phosphorus in the supernatant of MEC sludge was reclaimed by ectopic recovery of struvite crystals under optimum pH value of 10, Mg²⁺ concentration of 0.056 mol·L^-1 and NH₄⁺ concentration of 0.08 mol·L^-1. The mass of struvite crystal was up to 7.6 g·L^-1 and the highest crystal purity was 88.30%, and 77.55% of the phosphorus in the supernatant was recovered in the form of struvite. The economic value of hydrogen and phosphorus recovered from excess sludge with the proposed system reached 2.36 yuan. The experimental results show that the Fe³⁺/PCA/H₂O₂ system can improve phosphorus release from sludge and hydrogen production efficiency in an MEC system,which provides a new research strategy for sludge recycling.