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Project properties |
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| Title | Evaluating environmental and crop contamination risks of sub-surface irrigation with treated wastewater |
| Group | Soil Physics and Land Management group |
| Project type | thesis |
| Credits | 24-39 |
| Supervisor(s) | George Bier, Darrell Tang |
| Examiner(s) | Sjoerd van der Zee |
| Contact info | george.bier@wur.nl , darrell.tang@wur.nl |
| Begin date | 2021/05/25 |
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| Description | Sub-surface irrigation (SSI) of crops may be done with water of marginal quality, such as the effluent of wastewater treatment plants (WWTP), in order to conserve freshwater. Such water contains contaminants that WWTPs are unable to fully treat. However, much of the contaminants are organic contaminants (e.g. sewage, pharmaceuticals) that biodegrade in the soil. The idea of SSI is thus to inject effluent beneath the water table to increase the hydraulic head and maintain shallower groundwater levels during dryer periods, so that crops have access to water without being exposed to effluent, while contaminants in the effluent layer biodegrade over time. The pipes used for SSI function as drains during wetter periods, which prevents waterlogging of crops and allows some contaminants to be removed. Nevertheless, there is a risk that some contaminants will spread and be taken up by plants, or be discharged into adjacent rivers and canals. We will evaluate this risk using simulations with models such as MODFLOW, and relate the findings to data obtained from our experimental maize farm. Factors that we may consider include regional groundwater flow, rainfall, adsorption, and biodegradation. |
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