The effect of loess addition on the settling ability of activated sludge.

In this research, loess addition was investigated as a possible means of controlling the bulking sludge generated from a sequencing batch reactor (SBR) system treating a synthetic wastewater. The specific objective was to investigate whether loess changed the morphology of the sludge (i.e.

Kinetic study of adsorption of arsenic onto New Zealand Ironsand (NZIS).

New Zealand Ironsand (NZIS), an iron-rich sand ubiquitous to the coast of the North Island of New Zealand was examined for the removal of arsenic (both As (III) and As (V)) by adsorption. Batch experiments were performed to evaluate the adsorption kinetics at three different pH conditions (3.0, 7.

Biodegradation of industrial-strength 2,4-dichlorophenoxyacetic acid wastewaters in the presence of glucose in aerobic and anaerobic sequencing batch reactors.

This research explored the biodegradability of 2,4-dichlorophenoxyacetic acid (2,4-D) in two laboratory-scale sequencing batch reactors (SBRs) that operated under aerobic and anaerobic conditions. The potential limit of 2,4-D degradation was investigated at a hydraulic retention time of 48 h, using glucose as a supplemental substrate and increasing feed concentrations of 2,4-D; namely 100 to 700 mg/L (i.e.

Effects of hydraulic and solids retention times on productivity and settleability of microbial (microalgal-bacterial) biomass grown on primary treated wastewater as a biofuel feedstock.

High biomass productivity and efficient harvesting are currently recognized challenges in microbial biofuel applications. To produce naturally settleable biomass, combined growth of native microalgae and bacteria was facilitated in laboratory sequencing batch reactors (SBRs) using primary treated wastewater from the Christchurch Wastewater Treatment Plant (CWTP) in New Zealand. SBRs were operated under a simulated, local, summer climate (i.

Two-phase anaerobic digestion of the organic fraction of municipal solid waste: estimation of methane production.

Energy generation from methane (CH(4)) is one of the primary targets of the anaerobic digestion process. Consequently, the focus of this study was to investigate the effect on CH(4) production of total solids (TS) loading (measured as % TS) and hydraulic residence time (HRT) during the treatment of the organic fraction of municipal solid waste (OFMSW). Laboratory-scale, two-phase anaerobic digestion systems were employed with each system consisting of an acidogenic reactor and a methanogenic reactor linked in series.

Removal of arsenic from water using the adsorbent: New Zealand iron-sand.

Adsorption is a technology used to remove arsenic from water contaminated at levels above drinking water standards. In this study, New Zealand Iron-Sand (NZIS), a naturally-available adsorbent was investigated for its efficiency in removing both As (III) and As (V). Several batch tests were conducted with different concentrations of arsenic at different pH conditions.

Effect of mixture ratio, solids concentration and hydraulic retention time on the anaerobic digestion of the organic fraction of municipal solid waste.

This paper describes how the degradation of the organic fraction of municipal solid waste (OFMSW) is affected through codigestion with varying amounts of return activated sludge (RAS). Solid waste that had its inorganic fraction selectively removed was mixed with RAS in ratios of 100% OFMSW, 50% OFMSW/50% RAS, and 25% OFMSW/75% RAS. The total solids (TS) concentration was held at 8% and three anaerobic digester systems treating the mixtures were held (for the first run) at a total hydraulic retention time (HRT) of 28 days.

The use of naturally generated volatile fatty acids for herbicide removal via denitrification.

This research focuses on the removal of 2, 4-D via denitrification, with a particular emphasis on the effect of adding naturally generated volatile fatty acids (VFAs) as a carbon source. These VFAs had been produced from an acid-phase anaerobic digester (mean VFA concentration of 3153 +/- 801 mg/L [as acetic acid]). The first step involved developing 2, 4-D degrading bacteria in a sequencing batch reactor (SBR) fed with both sewage and 2, 4-D (30-100 mg/L).

The effect of arsenite on denitrification using volatile fatty acids (VFAs) as a carbon source.

A lab-scale sequencing batch reactor (SBR) was operated at a solids retention time (SRT) of 20 +/- 2.5 days to develop a consortium of denitrifying bacteria with a mean specific denitrification rate of 0.11 g nitrate (NO(3)(-)-N)/g volatile suspended solids (VSS)/day.

Effect of a starch-rich industrial wastewater on the acid-phase anaerobic digestion process.

This research investigated the effect of varying the starch-rich, industrial-wastewater component of mixtures with municipal wastewater fed to an anaerobic digester. A laboratory-scale, completely-mixed anaerobic digester was operated at an HRT of 30 h, an SRT of 10 d, and an ambient temperature of 21.5 +/- 1.