Powdered ALLODUST/ALLOCHAR augmented Single Batch Aerobic Reactor (SiBAR) for high concentration phosphorous removal from agricultural wastewater

Abstract

Phosphates enter the surface waters from agricultural sources has been regarded as an important cause of eutrophication. Excess of phosphate concentration can cause severe health problems such as kidney damage and osteoporosis. The adsorption is one of the most popular removal methods used for treating wastewaters containing agricultural nutrients. The challenge is the time that phosphorous concentration is very high in agricultural related industries and is higher than the adsorption capacity of the system. This research investigated the treatment of agricultural wastewater by developing and adding two novel media (ALLODUST, ALLOCHAR) to a Single Batch Aerobic Reactor (SiBAR). ALLODUST and ALLOCHAR consisted of allophanic soil mineral material sourced from either a Horotiu soil (Allophanic soil) or a Craigieburn soil (Allophanic Brown soil). Central Composite Design (CCD) and Response Surface Methodology (RSM) were hired to design the experiment and model the nature of the response surface of the novel media in the experimental design and to analyze the optimum operational conditions. The SiBAR design was optimized for three ranges of P contamination: 1-50 mg L⁻¹ (low range); 51-175 (mid-range); and 176-300 (high range). The ALLODUST novel media demonstrated a higher P adsorption capacity compared to the ALLOCHAR media and Allophane compound itself. The ALLODUST adsorbent dosage of 3 g L⁻¹ was the optimum: being able to remove 100% of P up to 50 mg L⁻¹ in 30 minutes with the lowest aeration rate (1.5 L min⁻¹) and remove 76% of P up to 300 mg L⁻¹ in 450 minutes with the highest aeration rate (7.5 L min⁻¹).