Mineralization of nitrogen in biosolids applied to soil | |
| Author | Suppakiet Sripanomtanakorn |
| Call Number | AIT Diss. no. EV-02-02 |
| Subject(s) | Sewage sludge--Thailand--Bangkok Soils--Nitrogen content--Thailand--Bangkok |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | In Thailand and other tropical regions, limited information exists on the effects of biosolids on crop N utilization and plant available nitrogen (PAN). This study investigated the mineralization of N in biosolids applied to soil by using an incubation-leaching technique. Field experiments with sunflower (Helianthus annuus) and tomato (Lycopersicon esculentum) crop were conducted to quantify the PAN of the applied biosolids, and to evaluate the N uptake rates of these crops grown in heavy clay soil in central Thailand. The results from the 16-week incubation study showed the potentially mineralizable N to be 39-107 mg N kg·1 and 105-202 mg N kg·1 in the anaerobically digested sludge and septic tank sludge samples, respectively. A modified first-order kinetic model based on two available N pools having different mineralization rate constants was found to adequately describe the cumulative N mineralization rates with time for both biosolids types. A significant difference in the potentially mineralizable N was observed when the same biosolids was applied to different soil types and a positive relationship between the total N content of the soils and the potentially mineralizable N in the biosolids was observed. The field experimental results indicated the feasibility of applying these biosolids to grow crops in the tropics. The applications of the anaerobically digested sludge and the septic tank sludge resulted in the yields of sunflower seeds and tomato fruits and plant N uptakes comparable to or better than those applied with only the chemical fertilizer and the control without any sludge application. The estimated PAN of the anaerobically digested sludge was about 27-43% of the sludge organic N during the growing season. Due to the unstabilized characteristics of the septic tank sludge, its PAN varied from 15-58%. An increased application rate of the septic tank sludge incorporated into this heavy clay soil under the cropping system resulted in a decreased N mineralization rate, probably due to the organic N immobilization in the soil-sludge systems. In addition, the high organic C content and high C/N ratio of the septic tank sludge could enhance the occurrence of potential denitrification loss from the sludge N applied, resulting in the reduction of crop yield and N uptake of crops. |
| Year | 2002 |
| Type | Dissertation |
| 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) | Chongrak Polprasert; |
| Examination Committee(s) | Annachhatre, Ajit P.;Shivakoti, Ganesh P.;Bernuth, Robert Von; |
| Scholarship Donor(s) | -; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology |