Wastewater treatment

This is a system improvement and energy savings program for a Sewage Treatment Plant treating wastewater coming from a shopping mall operation. Wastewater from shopping mall is considered domestic wastewater, which needs a big volume of water, and produced big amount of wastewater. Generators of wastewater such as in this case, from shopping mall, is mandated to be responsible for the collection, treatment of wastewater, and the ultimate disposal of the treated wastewater, as well as the separated solids, in a manner that is safe, and within the new effluent regulations as provided under DENR Administrative Order No. 2016-08. Under this new effluent regulations which only takes effect on June 2016, shopping mall is now mandated to meet stringent parameters to comply, particularly on Nitrate, Phosphate, Ammonia and Surfactants. To comply the new general effluent regulations, there were innovative solutions and energy programs implemented, resulting of savings in water and energy.

In the Philippines, DENR has mandated the regulation of oil and grease, COD, and TSS for automotive parts manufacturers. Wastewaters from industries have varying pollution strength that requires efficient treatment systems of combined physical, biological, and chemical processes. However, these methods tend to be labor intensive and costly. Constructed wetlands have become a popular treatment method for industrial wastewater because of its simplicity requiring less technical expertise compared to other technologies. In this study, four vertical subsurface flow constructed wetlands composed of cylindrical drums with diameter of 30 cm and height of 90 cm were designed to treat industrial wastewater in parallel experiments. The four constructed wetland units had various set-ups (with & without Canna X Generalis, with & without zeolite, with & without air vent) to determine the effect of the treatment efficiency. Water quality samples were collected from each unit, and were analyzed for pH, ORP, TSS, COD, aluminum, oil and grease. The findings show that the constructed wetland with zeolite and air vents demonstrated higher removal efficiency in comparison to a constructed wetlands without these features. The removal efficiencies registered 93.35% and 90.67% for COD and TSS, respectively.

Water is very precious and inevitable for every living objects including human beings. Huge quantity of waste water is generated by us every day and there are various methods to regenerate safe and pure drinking water from these waste waters. Researchers all over the world are continuously trying to develop low cost filtration system using various adsorbents. Agricultural waste products are being used as adsorbents and gaining momentum because of various attractive factors such as easy availability, low cost, non-toxic nature etc. In the present investigation, date pit (date stone) powder is used an adsorbent to remove Pb (II). The analysis revealed that date pit powder can be successfully used in a column filtration set-up to remove Pb (II) ions from the waste water streams with high efficiency.

Natural treatment systems are gaining preference as a wastewater treatment option since it is a form of ecosystem-based adaptation to climate change. The study investigated the performance of a laboratory scale horizontal, subsurface flow constructed wetland (SSFCW) planted with cogon grass (Imperata cylindrica) in reducing the pollutant concentration of slaughterhouse wastewater in Zamboanga City, Philippines. Results showed that the mean efficiency of BOD5 removal at seven (7) and 14 days detention time were 94.49 percent and 89.31 percent, respectively; while the average TSS removal efficiency were 97.8 percent and 99.9 percent, respectively. Statistical analysis of the BOD5 removal efficiencies revealed significant difference; which means that higher BOD5 removal is achieved at seven (7) days detention time. Analysis of the TSS removal efficiencies likewise revealed a significant difference, proving that longer detention time results in higher suspended solids removal. Therefore horizontal, SSFCW planted with cogon grass can be used to treat slaughterhouse wastewater at seven (7) days detention time. A pilot study is recommended to validate laboratory-scale finding. Future reseach should also investigate the performance of horizontal, SSFCW using other wastewater sources, different parameters, other endemic hydrophytic grasses, and to consider meteorological and climatological factors.

In this study, the applicability of a hybrid chemical/membrane process for the treatment of the boiler blow-down (BBD) water from steam assisted gravity drainage (SAGD) operation was explored. For the chemical pre-treatment prior to the membrane filtration, another waste stream of SAGD, i.e., ion exchanger regeneration wastewater (IERW), was used as a coagulant to reduce the concentration of organic matter and silica. The proposed method involved the direct use of the NF process for the purification of BBD water, followed by an integrated IERW conditioning and nanofiltration (NF) to purify the concentrated retentate. This process could operate with a zero-liquid discharge (ZLD) configuration and it was found to be an efficient method in terms of water recovery and water product quality.

In this study, fly ash zeolites (FAZ) of Na-X type were synthesized by alkaline atmospheric aging. FAZ with a specific surface value of 280 m2/g was tested for removal of contaminants from waters in comparison to unconverted FA. The adsorption efficiency of FAZ toward methylene blue from water solutions is over 60 % for the studied concentration levels. The removal efficiency of FAZ toward Cd2+-ions reaches 98 % and it is not affected by the pH from 3.0 to 7.0. The obtained results reveal that FAZ are suitable adsorbents in water remediation systems.

Preparation of activated carbon from agricultural bio-products is a promising way to produce useful adsorbents for Hg removal. In this study Aegina pistachio shells were used as raw materials and the activation was carried out by impregnation with ZnCl2 and heating at 750oC under N2 atmosphere. Three different levels of impregnation ratios (IR) were used for the chemical activation procedure, i.e. IR 1.0, 1.5 and 2.0 grams of ZnCl2 per gram of raw material. Further sulfurization treatment of the chemically activated carbons was also examined as a means to improve the adsorption capacity of activated carbons toward Hg. Overall six different types of activated carbons were produced and characterized regarding their physicochemical properties and their capacity to adsorb mercury. The specific surface area was determined by the BET method. The amount of acidic and basic function groups was determined with Boehm method and the surface chemical characteristics of activated carbons were investigated using the FT-IR spectroscopic method. Preliminary Hg adsorption experiments indicated that the sulfur modified carbons were much more efficient for the removal of Hg from aqueous streams compared to simple chemically activated carbons.

The continuous increase of water needs in sea site settlements, created the need to collect rain waters in order to use them, after their treatment to achieve the necessary quality improvement. To realize that we need at first to mark the water sources in the neighboring area of the serviced district, in order to collect the necessary water quantities, for the covering of the existing necessities. One part of the sustained pollution is removed from the water treatment installations but the rest remains in the natural medium. Further treatment includes the abstraction of pollutants by natural mechanisms, like biodegradation, photolyse, votalisation, adsorption, degradation, fixation from vegetables. Further water treatment will include addition of rain water coming from roofs and other waters from country side areas, when enough water quantities are available. The water will be treated with conventional methοds, in order to succeed the foreseen quality and finally get transferred to ZONES of REGECTION WITH SUITABLE VEFETATION (ZRV) for the elimination of micropollutants, as well as other pollutant traces.

Aerobic degradation of effluents contains tetramethylammonium hydroxide molecules (TMAH), coming from an electronic industry, was studied at laboratory and pilot scale. At the first, the preliminary experiments were conducted using a lab scale reactor inoculated with activated sludge coming from urban wastewater treatment. Several batches have been performed on real effluent, in which TMAH concentration was about 1800 mg/L. The results showed that after acclimation, the microorganisms removed 99% of TMAH in seven days. Kinetic studies have provided the following kinetic parameters able to describe the trends of TMAH, ammonium ions and biomass concentration as a function of time in the reactor: KS = 0.8 g/L; µmax = 0.042 h-1. Then, in a second phase the experiments were conducted at pilot scale using a pilot plant realized within Life Bitmpas project (LIFE15 ENV/IT/000332). The plant has three biological reactors of 1 m3 and it is possible to feed up to 25 L/h of TMAH effluent. The experiments were conducted in a continuous mode and the results showed that in 8 days the total degradation of TMAH was 99%; moreover, from kinetic study have been determined the following kinetic parameters: Ks = 0. 83 g/L and µmax = 0.0074 h-1.

Packaging paper wastewaters, stemming mainly from the dyeing sector of the production process (where printing inks are utilized), are characterized by large concentrations of organic matter, deep, strong color and almost zero biodegradability factor. These attributes, in combination with the presence of some toxic compounds (heavy metals, VOCs etc.) make further treatment necessary, before releasing the wastewater to the environment.
The present study deals with the treatment of these effluents using Electrocoagulation (EC). During the EC process, metallic species are electrochemically dissolved in the wastewater solution, resulting in coagulation, flocculation and subsequent separation of the pollutants via flotation or sedimentation. The efficiency of this method was evaluated, by examining the organic matter removal and decolorization of the wastewater under a wide range of operating parameters (current density, initial pH and electrode material). Moreover, the physical and chemical phenomena taking place during the process, as well its environmental footprint were investigated.
It was observed that this process is efficient under most of the operating conditions used, as the chemical oxygen demand removal ranged between 65 and 85 % and all the experiments managed high color removal, ranging between 98 - 100%. Additionally, secondary pollution was minimized, as concentrations of soluble metallic species remained below the regulated limits.

The aim of presented research is to use biochar produced from waste biomass for removal of veterinary antibiotic tiamulin from model wastewater. Produced biochar was activated using different chemical methods (KOH treatment under various conditions). It was characterised using BET method for the determination of the pore size distribution and pore volume fraction as well as SEM microscopy. Results indicated importance of biochar activation to achieve applicable adsorption characteristics. In 180 minutes of batch experiment up to 78% of tiamulin was removed. Kinetic parameters were also determined by Lagergren model while for determination of adsorption isotherm Freundlich model fitted obtained data. It was concluded, that adsorption characteristics of produced and activated biochar are comparable to those of commercially available activated carbons and thus its feasibility for removal of tiamulin from model wastewater was confirmed.