Do Wet-Dry Ratio and Fe-Mn System Affect Oxidation-Reduction Potential Nonlinearly in the Subsurface Wastewater Infiltration Systems?

Abstract

To understand characteristics of on-line oxidation-reduction potential (ORP) in a subsurface wastewater infiltration system (SWIS) under different intermittent influent conditions, ORP among five matrix depths at wet-dry ratios (Rwds) of 2:1, 1:1 and 1:2 with a hydraulic load of 0.10 m3·(m2·d)−1 were monitored. Results showed that the optimal Rwd for the SWIS was 1:1. In that case, ORP at 40 and 65 cm depths changed significantly, by 529 mV and 261 mV, respectively, from the inflow period to the dry period, which was conducive to the recovery of the oxidation environment. It was concluded that ORP varied nonlinearly in strongly aerobic and hypoxic environment. Wastewater was fed into the SWIS at 80 cm and dissolved oxygen diffused at the initial period of one cycle. As a consequence, ORP at 65 cm increased with water content increasing. However, ORP at 40 and 95 cm displayed inverse trends. Moreover, results showed that ORP decreased with Fe2+ and Mn2+ increasing under aerobic conditions (p < 0.05) because Fe2+ and Mn2+ moved with wastewater flow. Effluent met reuse requirements and no clogging was found in the SWIS during the operation.

Removal of Pollutants by Different Constructed Rapid Infiltration and Change in Surface Characteristics of Fillers

“…3 that the influent SS was 3.19-32.43 mg/L, exceeding the irrigation water quality standard of edible vegetables, melons and herbaceous fruits; the effluent SS of CRI1 was 0.76-3.43 mg/L, with an average SS removal rate of 69.93%; the effluent SS of CRI2 was 1.25-4.52 mg/L, with an average SS removal rate of 64.53%; the effluent SS of CRI3 was 0.03-3.67 mg/L, with an average SS removal rate of 66.21%. The average SS removal rate of the three groups of CRI was: CRI1>CRI3>CRI2, which may be because the influent water was the domestic sewage treated by ABR, the concentration of organic matter in the influent was lower, and the effective height of CRI3 was high (1.2 m), the microorganisms on the bottom filler got less nutrients, because of the lack of nutrients, some microorganisms were in the period of internal respiration or even decay, which leaded to the falling off of biofilm on the bottom filler, thus increasing the SS concentration in the effluent [19]; the effective height of CRI2 was the same as that of CRI3 (1.2 m), mechanical ventilation increased the dissolved oxygen in CRI2, resulting in more removal of organic matter by microorganisms on the upper filler, and less nutrients could got by microorganisms on the bottom filler, so the biofilm on the bottom filler dropped more and the removal rate of SS was the lowest.…”

Influence of shungite treatment methods on its absorption properties and on water treatment quality for beverages production

“…In modern conditions of production and consumption of different types of beverages (alcoholic and nonalcoholic), not only their chemical composition but also the physical indicators of beverages, which directly influence the processes of ensuring human life, are of particular importance [33]. One such indicator is the water oxidation-reduction potential [34]. This indicator of water characterizes the degree of activity of electrons in redox reactions indicates the biological activity and antioxidant property of water [35].…”

“…Regulatory documents that set requirements for the quality of drinking water and prepared value of the water oxidation-reduction potential is not regulated. In natural water, without its additional technological treatment, the value of the water oxidation-reduction potential varies widely from − 400 mV to +700 mV [33,34]. However, during water treatment the water oxidation-reduction potential increases to +200 -+400 mV [33,34].…”

“…In natural water, without its additional technological treatment, the value of the water oxidation-reduction potential varies widely from − 400 mV to +700 mV [33,34]. However, during water treatment the water oxidation-reduction potential increases to +200 -+400 mV [33,34]. In order to achieve a positive technological effect with the maximum preservation of natural properties and physicochemical characteristics of water, the influence of shungite treated in various ways the water oxidation-reduction potential was investigated ( Figure 6).…”