Strategies for sustainable phosphorus management and struvite recovery from digested sludge | |
| Author | Kalimuthu, Prashalini |
| Call Number | AIT Thesis no.EV-16-16 |
| Subject(s) | Phosphorus Phosphatic fertilizers Sludge disposal Sludge conditioning |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-16-16 |
| Abstract | Possibility of recovering phosphate as struvite from the digested sludge of the wastewater treatment plant is investigated in this research through supplementation by vegetable extracts. Experiments were conducted at laboratory scale by mixing digested sludge from piggery abattoir and vegetable extracts such as Spinach, Peas, Mushroom and Morning glory. Characterization studies brought out that pea extract was most suited for supplementation due to its high phosphorus content. It was found that phosphate recovery increased with the increase in the Mg concentration up to 16 moles/litre. For the substrates collected from the pig abattoir, a highest recovery of inorganic phosphate of 91% with MgCl2 addition at a molar ratio of Mg:NH4:PO4= 13:0.57:1 was obtained. Digested sludge with peas extract under acidic conditions showed phosphorus recovery rate greater than 100% due to conversion of organic phosphate into orthophosphate. 31% of phosphate recovery and 38% of ammonia recovery was obtained from the digested sludge and pea extract mix under water soluble conditions at a molar ratio Mg:NH4:PO4 = 0.02:1.23:1. Increasing ammonia molar ratio improved the quality of struvite crystals. Addition of chemical magnesium to the digested sludge peas extract mix sample increased the recovery of phosphate to 58% at a molar ratio of Mg:NH4:PO4=3.1:1.84:1 under acidic conditions and 30% underwater soluble conditions which is lower as compared to the recovery obtained by addition of MgCl2. |
| Year | 2016 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Annachhatre, Ajit P.; |
| Examination Committee(s) | Visvanathan, C. ;Soni, Peeyush; |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2016 |