The following sludge reduction alternatives were tested in wastewater biological reactors: oxic-settling-anaerobic (OSA-process); ultrasonic disintegration (UD); chlorination (CH); 3,3',4',5tetrachlorosalicylanilide (TCS); and folic acid (FA). Compared to the control system, UD reduced 55% of the sludge production, and greater substrate and nutrient removal efficiency was achieved. CH worsened ...

Maintaining growth through intensification in the New Zealand dairy industry is a challenge for various reasons, in particular sustainably managing the large volumes of effluent. Dairy farm effluents have traditionally been treated using two-pond systems that are effective in the removal of carbon and suspended solids, however limited in their ability to remove nutrients. In the past these nutr...

The aim of this study was to compare how conventional stem harvesting (CH) and whole-tree harvesting (WTH) in the first, and in some cases also in the second, thinning affect the needle nutrient status of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) stands in Finland. A series of 12 long-term field experiments was studied. The experiments were established during ...

We study chemostat models in which multiple species compete for two or more limiting nutrients. First we consider the case where the nutrient flow and species removal rates and input nutrient concentrations are all given positive constants. In that case, we use Brouwer degree theory to give conditions guaranteeing that the models admit globally asymptotically stable componentwise positive equil...

The aim of the study was to investigate the nutrient removal rate of three wastewater protozoan isolates (Aspidisca, Trachelophyllum and Peranema). The study was carried out in a laboratory-scale batch reactor for a period of 120 h. in a four batch study. Aliquot samples were withdrawn from the reactor every 24 h. for the analysis of phosphate, nitrate, nitrite, ammonia, chemical oxygen demand,...

Two batch experiments were conducted during the months of June-July (summer) and September-October (fall) to determine the effect of Electrical Conductivity (EC) on nutrient and COD removal & uptake efficiency and growth of duckweed (Lemna minor) at leachate with various EC levels (500-3,000 μS cm -1 ) under the natural climatic conditions of Islamabad, Pakistan. Maximum removal rates (mg m -2 ...

Microbial electrolysis cells (MECs) can be used to simultaneously convert wastewater organics to hydrogen and precipitate struvite, but scale formation at the cathode surface can block catalytic active sites and limit extended operation. To promote bulk phase struvite precipitation and minimize cathode scaling, a two-chamber MEC was designed with a fluidized bed to produce suspended particles a...

Floating Treatment Wetland (FTW) systems are purpose-built devices designed to replicate the water treatment processes that occur in and around naturally occurring floating vegetated islands. FTWs can be used to improve the water quality of water storage ponds by contributing to water treatment processes through adhesion, filtration, nutrient uptake (direct use by plants), and sequestration. Th...

Water reclamation and reuse is being actively promoted in Australia. In Queensland, surface-flow constructed wetlands with a diversity of macrophyte types offer the greatest potential for effluent polishing. Constructed wetlands in subtropical climates in coastal regions and arid climates in inland western regions are conducive to high macrophyte growth rates and nutrient removal, in particular...