Activated sludge wastewater treatment processes are difficult to be controlled because of their complex and nonlinear behavior; however, the control of the dissolved oxygen and nitrogen levels in the reactors plays an important role in the operation of the facility. For this reason a new approach is proposed in this work. The paper describes the theory and applications of a nonlinear control te...

The emissions of nitrous oxide (N(2)O) and nitric oxide (NO) from biological nitrogen removal (BNR) operations via nitrification and denitrification is gaining increased prominence. While many factors relevant to the operation of denitrifying reactors can influence N(2)O and NO emissions from them, the role of different organic carbon sources on these emissions has not been systematically addre...

This paper presents the plant-wide model Biological Nutrient Removal Model No. 2 (BNRM2). Since nitrite was not considered in the BNRM1, and this previous model also failed to accurately simulate the anaerobic digestion because precipitation processes were not considered, an extension of BNRM1 has been developed. This extension comprises all the components and processes required to simulate nit...

BACKGROUND In Iran, re-refinery industry has been developed many years ago based on the acid-clay treatment. Acidic sludge with high concentration of total petroleum hydrocarbon (TPH) is the final products of some facilities. In this study removal of TPH by aerated in-vessel composting was investigated. METHODS In order to microorganisms seeding and nutrient providing, urban immature compost ...

The primary driver for a successful biological nutrient removal is the availability of suitable carbon source, mainly in the form of volatile fatty acids (VFA). Several methods have been examined to increase the amount of VFAs in wastewater. This study investigates the mechanism of mechanical disintegration of thickened surplus activated sludge by a deflaker technology for the production of org...

An anaerobic-anoxic/oxic (AA/O) five-tank biological process called five-step continuous flow activated sludge process (FSCFASP) was developed to force the oscillation of organic matter and nutrient concentrations in process reactors. The run scheme and schematic diagram of FSCFASP was described. The run cycle was divided into two symmetrical half cycles with eight periods during each cycle. Th...

Centralized wastewater treatment plants remove nutrients prior to discharge. Recently, technologies have become available manage at different scales (individual buildings, neighborhoods/communities, or large centralized plants). Nutrient-recovery applied upstream of the plant may affect both flow rates and nutrient fluxes reaching plant. This study evaluates how introduction such affects effici...

The use of algae to treat wastewater has been under investigation for decades. Laboratory experiments were performed to study the growth rate and nitrate and phosphate uptake of free and immobilized cells of saline tolerant, nitrogen fixing cyanobacterium Gloeocapsa gelatinosa. The immobilization was carried out in calcium alginate matrix. The immobilized cells were found to be highly effective...

Organic products generated from waste activated sludge hydrolysis and fermentation process could be used as supplementary carbon source for enhanced biological nutrient removal. However, accompanied with organics production, large amount of ammonia nitrogen (NH4+-N) and soluble orthophosphorus (SOP) released, which would be negative to the reutilization of sludge carbon source. In this study, b...

this laboratory study simultaneously was conducted to evaluate the resistance to heavy metals, silver, cadmium and a number of commonly used antibiotics. sampling was done in 2014 of the two silver workshops in isfahan, and the inlet of phase 2 of shahin shahr wastewater treatment plant, isfahan. to isolate resistant bacteria to metal silver and cadmium and review multiple resistance to other m...