Treatment of agricultural drainage water via downflow hanging sponge system for reuse in agriculture

2013 ◽  
Vol 13 (2) ◽  
pp. 403-412 ◽  
Author(s):  
Amr Fleifle ◽  
Ahmed Tawfik ◽  
Oliver C. Saavedra ◽  
Mohamed Elzeir

Treatment of agricultural drainage water (ADW) in a down-flow hanging sponge (DHS) reactor has been investigated for a period of 1 y. The reactor was operated at different hydraulic retention times (HRTs) of 5.26, 2.63, and 1.5 h and corresponding organic loading rates (OLRs) of 2.01, 1.86, and 4.43 kg COD/m3 d, respectively. The results obtained indicated that, decreasing the HRT from 5.26 to 1.5 h negatively affected the chemical oxygen demand (COD) removal. Average COD percentage removal values dropped from 89.3 ± 5.4 to 72.2 ± 16% respectively. Total suspended solids (TSS) concentrations were reduced by 85.5 ± 8.3, 90.4 ± 2.1, and 91.4 ± 4.9 at HRTs of 5.26, 2.63, and 1.5 h, respectively. However, the nitrification efficiency was slightly decreased from 85.2 ± 17.4 to 82 ± 11.4% by decreasing the HRT from 5.26 to 1.5 h and increasing the OLR from 2.01 to 4.43 kg COD/m3 d, respectively. Likewise, reducing the HRT from 5.26 to 1.5 h exerted a slight negative effect on the removal of the total phosphorus (TP). Based on these results it is recommended to operate such a system at a HRT of 2.63 h and OLR not exceeding 2.0 kg COD/m3 d for providing an effluent quality complying with the standards regulating the use of treated wastewater for agricultural purposes.

1987 ◽  
Vol 19 (12) ◽  
pp. 265-271
Author(s):  
P. R. Thomas ◽  
H. O. Phelps

The investigation was based on two facultative stabilization ponds initially designed to operate in parallel, and now receive wastewater in excess of their capacities from a fast expanding housing estate in the Caribbean Island of Trinidad. Because of the deterioration of the effluent quality relative to acceptable standards, an attempt was made to upgrade the ponds using water hyacinths at the early stages. However, from the results, it was clear that the introduction of water hyacinths in the test pond did not lead to any substantial improvement in the effluent because of the high loading on the pond. Therefore the ponds were modified to operate in series with surface aerators installed in the first pond. Initially, the effluent quality was monitored in terms of total suspended solids, volatile suspended solids, biochemical oxygen demand, faecal coliform bacteria, pH and dissolved oxygen with aeration in the first pond and no aquatic plants in the second pond. Although there was a significant improvement in the effluent quality, the values remained above the standards. As a result, water hyacinths were introduced in the second pond and the effluent quality monitored together with aeration in the first pond. The effluent quality improved with total suspended solids and biochemical oxygen demand values both as low as 10 mg/l in certain months, but additional treatment was needed to reduce faecal conforms.


2021 ◽  
Vol 9 (6) ◽  
pp. 1331
Author(s):  
Arnaud Jéglot ◽  
Sebastian Reinhold Sørensen ◽  
Kirk M. Schnorr ◽  
Finn Plauborg ◽  
Lars Elsgaard

Denitrifying woodchip bioreactors (WBR), which aim to reduce nitrate (NO3−) pollution from agricultural drainage water, are less efficient when cold temperatures slow down the microbial transformation processes. Conducting bioaugmentation could potentially increase the NO3− removal efficiency during these specific periods. First, it is necessary to investigate denitrifying microbial populations in these facilities and understand their temperature responses. We hypothesized that seasonal changes and subsequent adaptations of microbial populations would allow for enrichment of cold-adapted denitrifying bacterial populations with potential use for bioaugmentation. Woodchip material was sampled from an operating WBR during spring, fall, and winter and used for enrichments of denitrifiers that were characterized by studies of metagenomics and temperature dependence of NO3− depletion. The successful enrichment of psychrotolerant denitrifiers was supported by the differences in temperature response, with the apparent domination of the phylum Proteobacteria and the genus Pseudomonas. The enrichments were found to have different microbiomes’ composition and they mainly differed with native woodchip microbiomes by a lower abundance of the genus Flavobacterium. Overall, the performance and composition of the enriched denitrifying population from the WBR microbiome indicated a potential for efficient NO3− removal at cold temperatures that could be stimulated by the addition of selected cold-adapted denitrifying bacteria.


2013 ◽  
Vol 69 (2) ◽  
pp. 269-277 ◽  
Author(s):  
C. Da Ros ◽  
C. Cavinato ◽  
F. Cecchi ◽  
D. Bolzonella

In this study the anaerobic co-digestion of wine lees together with waste activated sludge in mesophilic and thermophilic conditions was tested at pilot scale. Three organic loading rates (OLRs 2.8, 3.3 and 4.5 kgCOD/m3d) and hydraulic retention times (HRTs 21, 19 and 16 days) were applied to the reactors, in order to evaluate the best operational conditions for the maximization of the biogas yields. The addition of lee to sludge determined a higher biogas production: the best yield obtained was 0.40 Nm3biogas/kgCODfed. Because of the high presence of soluble chemical oxygen demand (COD) and polyphenols in wine lees, the best results in terms of yields and process stability were obtained when applying the lowest of the three organic loading rates tested together with mesophilic conditions.


Author(s):  
G. M. Chescheir ◽  
R. W. Skaggs ◽  
J. W. Gilliam ◽  
R. G. Broadhead

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