Hydraulic conductivity in soils irrigated with wastewaters of differing strengths: Field and laboratory studies

Soil Research ◽  
1999 ◽  
Vol 37 (2) ◽  
pp. 391 ◽  
Author(s):  
G. P. Sparling ◽  
J. C. Williamson ◽  
G. N. Magesan ◽  
L. A. Schipper ◽  
A. Rh. Lloyd-Jones
Keyword(s):  
Hydraulic Conductivity ◽  
Microbial Biomass ◽  
Oxygen Demand ◽  
Field Trials ◽  
Treated Wastewater ◽  
Unsaturated Hydraulic Conductivity ◽  
Soil Irrigation ◽  
Microbial C ◽  
Soil Pores ◽  
Allophanic Soil

Application of wastewater can decrease the hydraulic conductivity of soils, and so reduce future loading rates. A possible mechanism for this decrease is blockage of soil pores by microbial growth and extracellular carbohydrate production. Our objective was to determine whether wastewater characteristics that increased microbial biomass and carbohydrate also decreased soil hydraulic conductivity. In field trials, irrigation of secondary-treated wastewater for 7 years onto a sandy soil increased carbohydrate, but had no effect on microbial C or unsaturated hydraulic conductivity, relative to non-irrigated soil. Irrigation of tertiary-treated wastewater for 5 years onto an allophanic soil had no significant effect on these soil characteristics. Effects on soil properties of wastewater with differing carbon : nitrogen (C : N) ratio were examined in the laboratory on repacked cores of the allophanic soil over 14 weeks. Unsaturated hydraulic conductivity decreased significantly in cores irrigated with the high C: N wastewater. These cores also exhibited an increase in soil carbohydrate content, microbial biomass, and respiration relative to cores irrigated with water. This study has demonstrated that the land treatment of industrial wastewaters of high C: N ratio and high biochemical oxygen demand could be problematic, even on freely draining soils.

Changes in soil properties after application of dairy factory effluent to New Zealand volcanic ash and pumice soils

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 505 ◽  
Author(s):  
Graham P. Sparling ◽  
Louis A. Schipper ◽  
John M. Russell
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Management Practices ◽  
Pasture Production ◽  
Total N ◽  
Organic C ◽  
Unsaturated Hydraulic Conductivity ◽  
Microbial C ◽  
Dairy Factory Effluent ◽  
Changes In Soil Properties

In field studies, we assessed the effects of irrigation with dairy factory effluent on the surface (0–10 cm) properties of 3 rhyolytic tephra soils. Horotiu and Te Kowhai soils had been irrigated for 22 years and Taupo soil for 2 years. Soil properties measured were: total organic C, total N, pH, bulk density, unsaturated hydraulic conductivity, moisture release characteristics, readily and totally available water, particle density, microbial C, soil respiration, mineralisable N, denitrification enzyme activity, and nitrification potential. Matched, non-irrigated areas were sampled for comparison. Average annual loadings (kg/ha) of C, N, and P since 1990 were 1120 kg N, 560 kg P, and 36 300 kg C onto Horotiu soil, and 760 kg N, 380 kg P, and 25 200 kg C onto the Te Kowhai soil. These post-1990 loadings were, on average, 23% less than pre-1990 values. Irrigation for 22 years onto the Horotiu and Te Kowhai soils caused no change, or a slight decrease, in total C and N in the topsoil, but microbial C and mineralisable N contents were more than doubled, and N cycling activity much increased. Soil pH was increased by up to 1.8 units. Unsaturated hydraulic conductivity was increased from 8.5 to 49.8 mm/h on the Horotiu soil, and from 6.5 to 29.0 mm/h on the Te Kowhai soil. Irrigation increased the volumetric water content between 10 and 100 kPa. Most of the changes in soil properties suggest current application rates and pasture production can be maintained or increased. The high loading and mineralisation of N in the irrigated soils raises concerns about potential leaching of nitrate; current management practices are targeted towards minimising N loadings from effluent.

DECOLOURIZATION AND COD REMOVAL OF WASEWATER FROM ETHANOL PRODUCTION PROCESS FROM MOLASSES BY COAGULANTION USING INORGANIC ALUM

2010 ◽  
Vol 13 (3) ◽  
pp. 92-102
Author(s):  
Trung Duc Le
Keyword(s):  
Ethanol Production ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Treatment Processes ◽  
Physico Chemical ◽  
Biological Methods ◽  
Treatment Step ◽  
Main Material

The industrial production of ethanol by fermentation using molasses as main material that generates large quantity of wastewater. This wastewater contains high levels of colour and chemical oxygen demand (COD), that may causes serious environmental pollution. Most available treatment processes in Vietnam rely on biological methods, which often fail to treat waste water up to discharge standard. As always, it was reported that quality of treated wastewater could not meet Vietnameses discharge standard. So, it is necessary to improve the treatment efficiency of whole technological process and therefore, supplemental physico-chemical treatment step before biodegradation stage should be the appropriate choice. This study was carried out to assess the effect of coagulation process on decolourization and COD removal in molasses-based ethanol production wastewater using inorganic coaglutant under laboratory conditions. The experimental results showed that the reductions of COD and colour with the utilization of Al2(SO4)3 at pH 9.5 were 83% and 70%, respectively. Mixture FeSO4 – Al2(SO4)3 at pH 8.5 reduced 82% of colour and 70% of COD. With the addition of Polyacrylamide (PAM), the reduction efficiencies of colour, COD and turbidity by FeSO4 – Al2(SO4)3 were 87%, 73.1% and 94.1% correspondingly. It was indicated that PAM significantly reduced the turbidity of wastewater, however it virtually did not increase the efficiencies of colour and COD reduction. Furthermore, the coagulation processes using PAM usually produces a mount of sludge which is hard to be deposited.

scholarly journals Efficiency and Technological Reliability of Contaminant Removal in Household WWTPs with Activated Sludge

2021 ◽  
Vol 11 (4) ◽  
pp. 1889 ◽  
Author(s):  
Agnieszka Micek ◽  
Krzysztof Jóźwiakowski ◽  
Michał Marzec ◽  
Agnieszka Listosz ◽  
Tadeusz Grabowski
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Treated Wastewater ◽  
Contaminant Removal ◽  
Nitrogen And Phosphorus ◽  
Wastewater Samples ◽  
Polish Law

The results of research on the efficiency and technological reliability of domestic wastewater purification in two household wastewater treatment plants (WWTPs) with activated sludge are presented in this paper. The studied facilities were located in the territory of the Roztocze National Park (Poland). The mean wastewater flow rate in the WWTPs was 1.0 and 1.6 m3/day. In 2017–2019, 20 series of analyses were done, and 40 wastewater samples were taken. On the basis of the received results, the efficiency of basic pollutant removal was determined. The technological reliability of the tested facilities was specified using the Weibull method. The average removal efficiencies for the biochemical oxygen demand in 5 days (BOD5) and chemical oxygen demand (COD) were 66–83% and 62–65%, respectively. Much lower effects were obtained for total suspended solids (TSS) and amounted to 17–48%, while the efficiency of total phosphorus (TP) and total nitrogen (TN) removal did not exceed 34%. The analyzed systems were characterized by the reliability of TSS, BOD5, and COD removal at the level of 76–96%. However, the reliability of TN and TP elimination was less than 5%. Thus, in the case of biogenic compounds, the analyzed systems did not guarantee that the quality of treated wastewater would meet the requirements of the Polish law during any period of operation. This disqualifies the discussed technological solution in terms of its wide application in protected areas and near lakes, where the requirements for nitrogen and phosphorus removal are high.

scholarly journals Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

2015 ◽  
Vol 63 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Karsten Schacht ◽  
Bernd Marschner
Keyword(s):  
Hydraulic Conductivity ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Treated Wastewater ◽  
Soil Aggregate Stability ◽  
Irrigation Effects ◽  
Physical And Chemical ◽  
The Impact

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.

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