Well washing process modelling

The study of the influence of technical and technological factors on the efficiency of well flushing was car-ried out under experimental conditions. The analysis of existing experimental installations is performed with the help of which it is possible to assess the influence of technical and technological factors on the process of well flushing. The laboratory facility for modeling the well flushing process was designed using similarity criteria ob-tained in accordance with the basic provisions of the theory of dimensions. The developed installation allows you to model and study the influence of many factors on the well flushing process due to its compact overall dimen-sions and ease of conducting experiments, namely: the eccentric placement of the drill string; the type of flushing fluid (rheological properties); the size of the rock fraction; the frequency of pulsations to create a pulsating char-acter of the fluid movement; rotation of the drill string; longitudinal movement of the drill string. The main factors of influence and the range of their changes on the efficiency of sludge transportation are determined on the basis of previous studies. An experiment plan is constructed to study the significance of factors on the quality of sludge removal from the well bore using the «Taguchi» plan. Data processing was performed in the software «Mathcad Prime». Variations in factors lead to an improvement in the quality of well flushing, by reducing the area of sludge settling in the wellbore. The flow rate of the washing liquid has the most positive effect on the removal of sludge. The size of the rock fraction and the longitudinal movement of the drill string has the least impact. Pulsa-tion of the washing liquid has a significant impact on the quality of sludge removal, which is a significant and interesting factor from the point of view of further scientific research.

Investigation of anaerobic side-stream phosphorus recovery and its effect on the performance of mainstream EBPR subjected to low-consumption

In this study, phosphate-rich supernatant at the end of anaerobic phase was extracted by a certain side-stream ratio for chemical precipitation to investigate the optimal conditions for phosphorus recovery. The effect of side-stream reaction on the performance of the mainstream enhanced biological phosphorus removal (EBPR) system was also explored. The experiment was carried out in a sequencing batch reactor (SBR) operated in an alternating anaerobic/aerobic mode with dissolved oxygen controlled at 1.0 mg · L−1. The results showed that the optimum magnesium source,temperature, stirring speed and reaction equilibrium time for side-stream phosphorus recovery were: MgCl2 · 6H2O, 25 °C, 150 rpm and 20 min, respectively. It was also observed that the average phosphorus removal efficiency of the mainstream system maintained as high as 90.7% during the side-stream extraction period despite insufficient time for phosphate uptake under limited dissolved oxygen condition and phosphate deprivation of polyphosphate-accumulating organisms (PAOs). Besides, the sludge settling performance of the mainstream EBPR system decreased with no sludge loss. Afterwards, phosphorus removal and sludge settling performance were restored with dismissing side-stream phosphorus recovery. This study suggested that side-stream extraction of anaerobic supernatant from a mainstream EBPR subjected to low dissolved oxygen conditions for chemical phosphorus recovery was feasible and environmentally friendly.

Improvements on activated sludge settling and flocculation using biomass-based fly ash as activator

Biomass-based fly ash and wastewater are undesired products of the pulping industry. Recently, the use of biomass-based fly ash as an adsorbent (i.e., a valued material) for constituents of wastewater effluents was reported. In this work, the settling performance and properties of activated sludge were studied in the presence of fly ash. Upon mixing, fly ash increased the zeta potential of the sludge from −31 mV to −28 mV, which was due to the release of cationic ions from fly ash in the sludge suspension. The sludge settling and its flocculation affinity were improved through the complexation of flocs and released cation ions from fly ash. The relationships between the protein/polysaccharide (PN/PS) ratio and the content of extracellular polymeric substances (EPS) as well as the ratio and the properties of the sludge flocs were determined. A correlation between the total loosely bound-EPS (LB-EPS) content and the effluent suspended solids (ESS) (Pearson’s coefficient, rp = 0.83) was observed. The performance of sludge flocculation and settling were much more closely correlated with LB-EPS than with tightly bound EPS (TB-EPS). Scanning electron microscopy (SEM) analysis of sludge flocs before and after EPS extraction showed that the sludge flocs contained a large number of microorganisms, mainly Bacillus and Cocci. The amount of LB-EPS had an adverse influence on bioflocculation, effluent clarification and sludge settling affinity. The sludge properties had a moderate relationship with the PN/PS ratio of LB-EPS. Also, no correlation could be established between the ratio and the TB-EPS content.

Perencanaan Instalasi Pengolahan Air Limbah Mal X Kota Bandung

<p>Waste Water Treatment Plant (WWTP) in the shopping center is planned to cater for its constantly changing concept. The centre was to initially provide electronic services, however, it is currently providing food and beverage services. The changes will affect the amount of wastewater and the characteristics produced. Wastewater discharge is calculated from 80% of the 83.73m of clean water needed per day. The concentration of the wastewater characteristics obtained for parameters BOD, COD, TSS, oil and fat were 182.67 mg/l, 328.50 mg/l, 255.92 mg/l, 47.93 mg/l respectively. The selection of the processing alternatives is based on the descriptive method which uses a series of selected alternative unit screens, grease traps, equalization tanks, activated sludge, settling tanks and chlorination. The dimensions of the processing unit are calculated based on the selected alternatives. And the land requirements needed to build a WWTP at X Mall amounts to 80m²</p>

Use of floating seals to exclude oxygen penetration in non-aerated selectors

It is widely assumed that non-aerated selectors are very efficient in nutrient removal, and especially anaerobic basins may largely contribute to good sludge settleability as well. However, based on results measured in full-scale, this paper draws attention to the fact that with decreasing availability of readily biodegradable carbon source (rbCOD) being experienced worldwide, oxygen penetration into non-aerated basins through the uncovered surface may no longer be considered negligible. When the oxygen mass transfer is significant compared to the available influent rbCOD, non-aerated selectors should be regarded as basins with low dissolved oxygen (low DO) concentrations that may underperform with respect to nutrient removal and favor the growth of filaments, especially during low-loaded conditions. In order to fully exclude oxygen penetration, floating seals have been developed and applied at the North-Budapest Wastewater Treatment Plant in Hungary. Comparative full-scale studies showed prevention of significant amounts of influent rbCOD loss (up to 60 mg/L) through the application of this new technology. This amount of saved, non-oxidised but fermented carbon source could be accordingly used for enhancing biological P-removal. Due to the elimination of microaerophilic conditions, the undesirable growth of filamentous bacteria could also be avoided, leading to significantly better activated sludge settling.

Treatment of Phosphoric Acid Sludge for Rare Earths Recovery I

A total of nine polymers were first tested. Correlations between molecular weight and sludge settling rate were identified for three types of polymers with a general trend of higher molecular weight giving a faster settling rate. Among the non-ionic polymers, the medium molecular weight polymer produced the best results (1831.88 ppm). Among the cationic flocculants, the lowest molecular weight polymer resulted in more REEs distribution (2478.81 ppm). It was concluded that the super high molecular weight of anionic flocculants works best for treating phosphoric acid sludge which resulted in REE concentration of 2568.69 ppm. Five co-polymers with different anionic ratio were tested as well. A higher anionic ratio resulted in faster settlement. It was found that the higher was the anionic ratio of the flocculant, the higher was REE concentration in the final solids and the highest anionic ratio polymer resulted in 2999.64 ppm of REE. This trend was attributed to zeta potential change due to addition of the polymer.