污泥发酵液主要成分对鸟粪石结晶法回收磷的影响

为了研究污泥发酵液中的主要无机离子和有机成分对鸟粪石结晶法回收磷的影响，选取钙和钾为典型无机离子，以与胞外聚合物（EPS）性质相似的海藻酸钠（SA）和腐殖酸的主要成分富里酸（FA）模拟污泥发酵液主要有机成分，利用小试流化床反应器进行连续流实验。结果表明，随着Ca2+浓度升高，除磷率先下降后上升，生成了无定形磷酸钙沉淀，当Ca2+浓度为100 mg·L-1时，鸟粪石纯度降至14.9%。实验浓度范围内，K+、SA与FA均使鸟粪石纯度降至90%以下，生成少量共沉淀物，但产物晶型仍以规则斜方晶为主，除磷率在80%以上。其中SA主要附着在鸟粪石表面，阻碍鸟粪石晶体的正常生长，随着SA浓度由0 mg·L-1升高到120 mg·L-1，产物纯度由96.0%降至77.3%，粉末状晶体增多，使产物平均粒径由0.80 mm降至0.56 mm。

Influence of major components in sludge fermentation liquid on phosphorus recovery using struvite crystallization

In order to investigate the influence of inorganic ions and organic components in sludge fermentation liquid on phosphorus recovery by struvite crystallization, the typical inorganic ions of calcium and potassium ones, and sodium alginate (SA) with the similar property to extracellular polymeric substances (EPS), as well as fulvic acid (FA), a main component of humic acid, were used to simulate the major organic component in sludge fermentation liquid. A bench-scale fluidized bed reactor was used to carry out the continuous flow experiment. The results indicated that the PO43--P removal efficiency first decreased and then increased as Ca2+ concentration increased, and amorphous calcium phosphate (ACP) was formed. When Ca2+ concentration was 100 mg·L-1, the struvite purity was as low as 14.9%. The presences of K+, SA and FA in the experimental concentration ranges reduce the struvite purity to less than 90% and generate a small amount of co-precipitates, but the products were mainly prismatic crystal and the PO43--P removal efficiency remained over 80%. The adsorption of SA on the struvite surface hindered the normal growth of struvite crystals. With the increase of SA concentration from 0 to 120 mg·L-1, the struvite purity decreased from 96.0% to 77.3%, and the average particle diameter of the product decreased from 0.80 mm to 0.56 mm due to the increase of powdery crystals.