Modification of agricultural waste/by-products for enhanced phosphate removal and recovery: Potential and obstacles

Effect of Substrate, Feeding Mode and Number of Stages on the Performance of Hybrid Constructed Wetland Systems

“…Thus, it can be concluded that the capacity of these reactors to remove dissolved phosphate-P was nil. Similarly to other forest and agricultural waste/by-products, the low efficiency of the palm mulch in the removal of the negatively charged phosphate ions can be attributed to the abundant availability of negatively charged functional groups (e.g., -OH, -COOH) and the absence of positively charged functional groups (e.g., -NH 2 ) on its surface [20]. Nevertheless, far from being a disadvantage the modest efficiency of CWs in the removal of N and P can be regarded as a way to decrease the demand for expensive inorganic fertilizers in agriculture [39].…”

“…This practice can have several environmental and economic advantages compared with mineral substrates (gravel and sand) by: (i) providing a viable solution to reduce waste materials in a cheap and eco-friendly way, (ii) adding economic value to the waste, (iii) reducing the impact of CWs construction as a renewable, locally abundant material would be used. Additionally, these materials offer an interesting advantage, which is their capacity to work as low cost bio-sorbents [19,20]. Ribé et al [21] observed that pine bark was able to efficiently remove heavy metals from landfill leachates.…”

Adsorption of phosphate from aqueous solutions and sewage using zirconium loaded okara (ZLO): Fixed-bed column study

“…Thus, there is a need to perform continuous adsorption studies. The proper use of agricultural by-products as phosphorus adsorbents usually requires modification (e.g., metal loading, quaternization, thermal treatment) (Nguyen et al, 2014a). Metal loading provides the bio-materials with positively charged metal ions, which are suitable for retention of negatively charged anions, such as phosphate (Mallampati and Valiyaveettil, 2013).…”

Struvite as alternative nutrient source for cultivation of microalgae Chlorella vulgaris

“…One viable source of phosphates is municipal wastewater. Struvite is a waste product at low cost with a chemical formula of NH 4 MgPO 4 6H 2 O, which could be formed by adding magnesium to wastewaters containing ammonia and phosphate [2][3][4][5]. A practical example presented in Nepal showed an affordable installation which precipitated urine as struvite using nylon filters and low dosage of magnesium [6].…”