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At least 595 records · Page 33Linked to original sources
PubMed2005

Olive oil mill wastewater purification by combination of coagulation- flocculation and biological treatments.

In order to define an efficient pre-treatment of Olive Oil Mill Wastewater (OOMW) to overcome major obstacles to biological treatment, various organic and mineral coagulants have been tested. In particular, the application of quicklime until a pH around 12 - 12.4 was reached, allowed the reduction of almost 37% of the initial COD, and approximately 88% and 71% of the colour and phenolic content of the waste. Hence, further biological treatments with an adapted aerobic consortium (AC) and a white rot fungus (WRF) strain were improved. The WRF Coriolopsis polyzona was more efficient than AC to reduce colour and polyphenols when the waste was prior diluted or pre-treated; however, it was less effective in COD removal. The combined treatment: lime - AC of OOMW having initial COD of 102 g l(-1) led to the elimination of about 77, 91 and 63%, of the COD, phenols and colour, respectively. Interestingly, the opposite combination AC - lime permitted better COD, phenols and colour reduction to respectively, 21, 11 and 11% of the initial values. This latter condition is technically recommended since only one step separation was needed and no pH correction was necessary before undergoing aerobic treatment. Moreover, the process would produce a sludge potentially rich in organic matter, and consequently, useful as an agricultural amendment or/and as an additive in animal nutrition.

Basidiomycota↗
PubMed2004

An algal removal using a combination of flocculation and flotation processes.

The paper describes certain facets of the removal of the algae (Scenedesmus quadricauda) from water, using a froth flotation separation method, in conjunction with two types of surfactants, (cetyltrimethylammonium bromide) CTAB and (sodium dodecylsulfate) SDS. A 90% algal removal efficiency was achieved when 100 mg l(-1) of CTAB was used whereas for the SDS solutions, the same concentration gave, by comparison, a very poor algal removal efficiency. An addition of 1 mg l(-1) of a commercial cationic polyelectrolyte, which was the optimal concentration as was evident from the zeta potential and the particle size distribution measurements, prior to the SDS addition resulted in a formation of algal flocs and consequently a substantial improvement in the extent of the algal removal. A 50 mg l(-1) solution of SDS was found to be the optimal concentration to completely remove these algal flocs from water. The amount of water removed along with the algal flocs, produced using 1 mg l(-1) of the commercial polyelectrolyte and subsequently removed using SDS, was comparatively lower than that removed with the algal cells when CTAB was used as the 'collector'. It was generally found, in this study, that an addition of the polyelectrolyte improved the removal efficiencies and the rate of separation and also decreased the amount of the associated water removed along with the algal sludge.

Cetrimonium↗
PubMed2005

Laboratory and pilot-scale phosphate and ammonium removal by controlled struvite precipitation following coagulation and flocculation of swine wastewater.

To reduce the suspended solids load to a trickling filter installation, raw swine effluent was pre-treated with ferric chloride and a cationically charged polyacrylamide coagulant resulting in unexpected struvite accumulation downstream of this post-separation process. Using this pre-treated swine manure, struvite precipitation studies were carried out as a function of pH at laboratory and pilot batch and continuously operated scales. An optimal reaction time of 30 min was established for struvite precipitation in the pre-treated swine wastewater at pH 8.5, minimizing the co-precipitation of interfering minerals. Ferric chloride addition resulted in magnesium solubilization, such that no external additional source of magnesium was required for struvite formation. Aeration alone did not result in significant pH increases, so base addition was required for pH adjustment. X-ray diffraction revealed that the only crystalline phase produced was struvite. Removal of phosphate and ammonium attained 98% and 17% respectively in laboratory scale experiments. At the pilot-scale, removal attained 99% and 15% of phosphate and ammonium in both batch and continuously HRT = 1h) operated reactors.

Animals↗