Some characteristics of organic soils irrigated with municipal wastewater

Abstract

Soil irrigation with wastewater (WW) gives the opportunity to solve the problems of its disposal, final purification or reuse. Many studies have examined mineral soils upon continued WW application. The aim of this paper was to examine the properties of organic soils 3 years after WW application was discontinued. Peat-muck soil planted with Populus spp. or Salix spp., and mineral-muck soil under grasses were irrigated for 4 years with municipal WW at a low (comparable with intensive NPK fertilization) and high WW rate (600 and 1200 mm yearly, respectively). Soils were analysed for organic matter (OM), pH, bulk density (BD), water holding capacity (WHC), P 2 O 5 , Fe 2 O 3 , Al 2 O 3 , MnO, Zn, Pb, Cu, Cr, magnetic susceptibility (MS) and dehydrogenase and catalase activities. The results were compared with control soils which have never received WW. The study showed that only P 2 O 5 , MnO and catalase activity (CA) were significantly affected by former WW application. On average, P 2 O 5 increased by 30 per cent, whereas MnO decreased by 35 per cent with no differences between the two WW rates. CA decreased by 18 per cent at the high WW rate. Most of tested characteristics were determined by soil type. The peat-muck soil showed higher OM, WHC, P 2 O 5 , MnO, Pb and CA than mineral-muck soil and lower BD, MS, Fe 2 O 3 , Al 2 O 3 and Cr. Soil depth influenced Fe 2 O 3 , MnO, Zn, MS and enzyme activities, while basic soil properties (OM, pH, BD, WHC and P 2 O 5 ) were not changed by soil depth. Heavy metals (Zn, Cr, Cu and Pb) were below upper permissible limits.

Effects of Different Land-Use Systems on Soil Aggregates: A Case Study of the Loess Plateau (Northern China)

“…The tendency of the increase in BD, Clm, and Clw is an indication of the effects of tillage and the higher application of inorganic fertilizer than Clw and other land-uses (Table 3). The results are in line with the findings of [27][28][29][30][31], which revealed that the BD of the soil surface layers could be reduced with no tillage compared to conventional tillage; and this study showed that the BD in the soil surface layers of AAO, GL, CAO, and SGL were slightly lower compared to Clm and Clw.…”

“…This is perhaps due to slightly higher WSA, GMD, and MWD in AAO and GL compared to the other types of land use. Similarly, according to the AAO and GL soil data, a slightly lower BD, higher WSA, MWD, GMD, and SOC in AAO and GL is due to less soil disturbance and higher SOM [27,29,31,37,40,[56][57][58]. …”

Impact of wastewater application on magnetic susceptibility in Terric Histosol soil

“…At this location, soil was classified as a peatmuck (Terric Histosol), according to the FAO classification. The basic soil properties were as follows: organic matter (OM) content 30.3-47.9%; pH 7.80-9.13 (in CaCl 2 ); bulk density 0.307-0.627 mg m -3 (Brzezińska et al, 2011). The experimental area was divided into two plots of 1 hectare area.…”

Measurement of activated sludge particle diameters using laser diffraction method / Pomiary średnicy cząstek osadu czynnego za pomocą metody dyfrakcji laserowej

“…The species composition of an active sludge organisms may also inform about possible malfunction of wastewater treatment plant biological part [3,5,14,15]. A safe use of dewatered sewage sludge, for example for agricultural application or recultivation of degraded areas, also depends on presence of heavy metals [16][17][18] and pathogenic organisms [19][20][21].…”

“…The species composition of an active sludge organisms may also inform about possible malfunction of wastewater treatment plant biological part [3,5,14,15]. A safe use of dewatered sewage sludge, for example for agricultural application or recultivation of degraded areas, also depends on presence of heavy metals [16][17][18] and pathogenic organisms [19][20][21].Particle diameter measurements can be conducted in many ways, and the most basic and the first to be applied were the microscope observation methods [11,12,22,23]. Neis and Tiehm used, among others, the membrane filtration method.…”