A simple method for analysis of the performance of aerated wastewater lagoons

Abstract

An aerated wastewater stabilization lagoon, or any subsection of the overall lagoon, should function as an oxidation reactor, a clarifier, and a sludge digester. A relatively simple set of calculations can be used to evaluate these three functions for zones within a lagoon system. Only SBOD, TSS, and NH4-N or PO4-P measurements are needed to support the analysis. The evaluation should be limited to bacterially dominated zones of a lagoon system, i.e. lack of significant algal influence.

The effects of nutrient limitation (nitrogen and phosphorus) on BOD removal from post-coagulated Pinus radiata sulfite pulp and paper mill wastewater in a baffled aerated stabilisation basin–laboratory pilot scale study

“…Note;*increasing occurred in simulation A, while simulation B had sufficient P. These findings are similar when compared with those results fromBryant (1995).…”

“…To investigate the recycling of N and P between the sediment and microbial growth the method of Bryant (1995) was used. Bryant (1995) developed a component mass balance for N and P in an ASB that was limited to bacterially dominated growth and had insignificant algal growth.…”

“…Bryant (1995) developed a component mass balance for N and P in an ASB that was limited to bacterially dominated growth and had insignificant algal growth. The mass balances, using a common formula of the chemical composition for bacterial biomass (C 5 H 7 O 2 NP 0.5 ), account for reactions, settling, and digestion efficiencies within a lagoon system.…”

“…According to Metcalf & Eddy (2003), concentrations of nitrite found in wastewaters often exceed 1 mg/L, while for nitrate the typical range for treated effluent is 15 to 20 mg/L as N. Low concentrations of NO x in treated effluent can be a limiting factor for growth of algae and development of algal blooms (Metcalf & Eddy 2003), and hence this is an operational target in treating wastewater prior to discharge. Bryant (1995) presented a method to assess the performance of ASB simulations, based on assumed nutrient feedback and biomass growth yields, which involves the estimation of the SBOD concentration. The method was applied in this study to give an insight into the possible removal mechanisms that occurred within the simulations.…”

“…In ASBs, sources of nutrient are an important consideration, which may derive from particular waste stream inputs and/or from the sludge within the basins. Bryant (1995) and Slade et al (1999) identified the important role of benthic feedback in ASBs, which acts as a mechanism for nutrient recycle.…”