Electrokinetic phosphorus recovery from packed beds of sewage sludge ash: yield and energy demand

Abstract

The static lifetime of primary phosphate stocks is estimated as one century. Thus, the exploitation of secondary phosphorus sources becomes increasingly important. This study focussed on the feasibility of an electrokinetic phosphorus recovery from sewage sludge ash (P-content *5 wt%). Packed bed experiments were conducted under varied electric conditions with and without acid pre-treatment and employing porous and ion exchange materials as electrode wells. Maximum values of phosphate concentration obtained in all experiments were around 2.5 g L -1 . Galvanostatic conditions were superior to potentiostatic conditions and acid pre-treatment is preferable over packed bed saturation with water. Ion-exchange membranes improved the product quality but increased the energy demand. Phosphorus recovery below 1% of the initial contents shows that the recovery setup must be improved in view of a marketable application.

Recovery of phosphorus from incinerated sewage sludge ash by combined two-step extraction and selective precipitation

“…Organic solvent extraction is not sufficiently efficient and also requires an additional step for P extraction from the solvent and solvent recovery before a phosphoric acid product can be obtained [10,23]. The removal of metal ions by direct current was found to be limited by high energy consumption and low efficiency [31,32]. Hence, it is necessary to find new methods which can effectively extract P with high purity through a simple process route.…”

Comparison of two different electrodialytic cells for separation of phosphorus and heavy metals from sewage sludge ash

“…These methods include acid and base treatment (Oliver and Carey, 1976;Levlin et al, 2003;Donatello et al, 2010;Ottosen et al, 2013), thermo (chemical) treatments (Adam et al, 2009) and electrodialytic remediation (Sturm et al, 2010). Electrodialysis (ED) is a treatment method mostly applied for remediation of heavy metal polluted soils, industrial effluents and more recently stirred suspensions such as harbor sediments (Kirkelund et al, 2009) and suspensions of dried sewage sludge and bio-ash (Ottosen et al, 2007).…”

“…Phosphorus recovery from secondary resources using ED has not been studied as extensively and requires further improvement. Sturm et al (2010) applied ED remediation on packed beds of sewage sludge ash in an attempt to recover P, but recovery rates remained below 1%.…”

Solar Cell-Combined Sediment Microbial Fuel Cell for Preserving Sediment and Water Environments

“…More detailed information concerning the decreasing pH and increasing ORP in sediments by electricity generation can be also found in the reports by Touch et al [10], Choi ta al. [15], and Sturm et al [16]. As such, the effective distance can be examined based on the decrease in pH and the increase of ORP.…”