Lignin rich solid residues after saccharification during the production of ethanol from lignocellulosic substrates are major concern during past times. These solid residues left after the saccharification of Coir pith and Bit fiber waste are pyrolysed at 350 oC to yield biochar, which has been characterized and its potential for removal of Malachite Green, a dye present in the effluents from coir product manufacturing units are studied. FTIR and XRD spectra revealed the diverse functional groups present on the surface of biochar. SEM images showed the porous structure of the biochar. A maximum dye removal efficiency of 99.5% was achieved using Coir Pith Biochar (1 %) within 24 hours of treatment at a dye concentration of 100 mg/l. The removal efficiency was 99.4 % using Bit Fiber Biochar (0.8 %) in the same treatment period. The efficiency of removal was enhanced on adjusting the pH to 4 at which the dye removal of 99.6 % and 99.7 % was achieved using Bit fiber biochar and Coir pith biochar respectively. The residence time was significantly reduced to 2 and 4 hours respectively for bit fiber and coir pith biochar at pH 4 and hence the produced biochars are cost effective adsorbents for removal of dyeing effluents in wastewater. The adsorption fits into pseudo-second order kinetics and is well described by langmuir isotherm model. This would also facilitate the sustainable use of spent solid substrates left after lignocellulosic ethanol production in a more economical way.

This work investigates the possibility of using constructed wetland system for the management of municipal wastewaters with reuse strategies for the irrigation of landscapes in Ouled Djellal city of Biskra, Algeria. The design of this system was based on the characteristics (volume and physico-chemical properties) of wastewaters and the urban plan of the studied city. Results showed that studied effluent is easily biodegradable with COD/BOD5 of  1.84 (< 3), BOD5 (325 - 365 mg/L), COD (620-644 mg/L) and TSS (120-250mg/l). The peak of raw wastewater flow was found to be 32.4 m3 /h, which was used for the calculation of drip network for the landscape irrigation. The selected variant for the configuration of the CW system is HF-VF-HF, which occupies an area of 11.580 m2 and will reduce significantly the water pollution. The treated wastewater will be reused for the irrigation of landscapes via the dimensioned drip network. Results of this study showed that the proposed design for the system (treatment and reuse) would be effective in reducing pollution in the urban environment by ensuring possibility of the reuse of the treated water for irrigation. This gives also a great opportunity for using this strategy in small neighborhoods in other cities.